U.S. patent application number 12/623637 was filed with the patent office on 2010-04-22 for check valve and pump including check valve.
This patent application is currently assigned to SEIKO EPSON CORPORATION. Invention is credited to Kazuo Kawasumi, Takeshi SETO, Kunihiko TAKAGI.
Application Number | 20100096027 12/623637 |
Document ID | / |
Family ID | 34467797 |
Filed Date | 2010-04-22 |
United States Patent
Application |
20100096027 |
Kind Code |
A1 |
SETO; Takeshi ; et
al. |
April 22, 2010 |
CHECK VALVE AND PUMP INCLUDING CHECK VALVE
Abstract
A check valve includes a tubular valve seat frame, a valve seat
that is fixedly secured to the inside of the valve seat frame and
has a communication hole through which a working fluid flows, and a
valve body that is on the working fluid outflow side of the valve
seat for opening and closing the valve seat. The valve seat frame,
the valve seat, and the valve body are put into one unit so that
the check valve has a simple structure and a good assembly
property, and can be manufactured at low cost. The check valve is
included, whereby a small, durable, and high-performance pump can
be provided.
Inventors: |
SETO; Takeshi; (Chofu,
JP) ; TAKAGI; Kunihiko; (Okaya, JP) ;
Kawasumi; Kazuo; (Chino Shi, JP) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Assignee: |
SEIKO EPSON CORPORATION
Tokyo
JP
|
Family ID: |
34467797 |
Appl. No.: |
12/623637 |
Filed: |
November 23, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10968865 |
Oct 19, 2004 |
7654283 |
|
|
12623637 |
|
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|
Current U.S.
Class: |
137/527 |
Current CPC
Class: |
F04B 53/1037 20130101;
F16K 15/16 20130101; Y10T 137/7891 20150401; F16K 15/147 20130101;
F04B 43/04 20130101; F04B 53/1047 20130101; Y10T 137/7898 20150401;
Y10T 137/7504 20150401; Y10T 137/7856 20150401 |
Class at
Publication: |
137/527 |
International
Class: |
F16K 15/03 20060101
F16K015/03 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 21, 2003 |
JP |
2003-360758 |
Nov 11, 2003 |
JP |
2003-381279 |
Claims
1. A check valve comprising: a tubular valve seat frame and a valve
seat being fixedly secured to the inside of said valve seat frame
and having a communication hole through which working fluid flows;
and a valve body being on the working fluid outflow side of said
valve seat for opening and closing said valve seat, wherein said
valve seat frame, said valve seat, and said valve body are put into
one unit; wherein said valve body is placed in a recess part
provided on said valve seat frame so that it can move in a
thickness direction, and wherein a ring-like fixing member for said
valve body to support the communication hole so as to be able to
open and close the communication hole is provided on the recess
part periphery of said valve seat frame.
2. The check valve as claimed in claim 1 wherein said valve seat is
formed of a material having higher hardness than that of said valve
seat frame and that of said valve body.
3. The check valve as claimed in claim 1 wherein said valve body is
made up of a fixing part on the periphery and an opening-closing
part of the communication hole of said valve seat and is provided
on the side of said valve seat where working fluid flows out and
the fixing part is fixedly secured to said valve seat frame.
4. A check valve comprising: a tubular valve seat frame and a valve
seat being fixedly secured to the inside of said valve seat frame
and having a communication hole through which working fluid flows;
and a valve body being on the working fluid outflow side of said
valve seat for opening and closing said valve seat, wherein said
valve seat frame, said valve seat, and said valve body are put into
one unit, and wherein said valve body is made up of a fixing part
on the periphery, an opening-closing part roughly at the center,
and a plurality of blade parts for concatenating the
opening-closing part and the fixing part.
5. The check valve as claimed in claim 4 wherein said valve seat is
formed of a material having higher hardness than that of said valve
seat frame and that of said valve body.
6. The check valve as claimed in claim 4 wherein said valve body is
made up of a fixing part on the periphery and an opening-closing
part of the communication hole of said valve seat and is provided
on the side of said valve seat where working fluid flows out and
the fixing part is fixedly secured to said valve seat frame.
Description
[0001] This application is a divisional of U.S. patent application
Ser. No. 10/968,865 filed on Oct. 19, 2004. This application claims
the benefit of Japanese Patent Application No. JP2003-360758 filed
Oct. 21, 2003 and JP2003-381279 filed Nov. 11, 2003. The
disclosures of the above applications are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a check valve that can be
built in a pump as a unit of a valve seat, a valve body, and a
valve sheet frame and a pump including the check valve.
DESCRIPTION OF THE BACKGROUND ART
[0003] Hitherto, a pump for allowing a working fluid to flow has
included a check valve as a resistance element in a fluid flow
pass. Particularly, there are check valves adopted for a small
motor for changing the volume of a pump chamber by a piston or a
diaphragm for allowing a working fluid to flow.
[0004] As the first related art, a structure of a check valve made
up of a pump suction and discharge unit having a suction port and a
discharge port of working fluid, a pump valve seat unit having a
suction side check valve and a discharge side check valve, and a
pump actuator unit with the pump valve seat unit fixed via an O
ring as a sealant between the pump suction and discharge unit and
the pump actuator unit and a pump including the check valve is
known as a structure for controlling working fluid when the working
fluid is sucked into a pump chamber, and discharging the working
fluid into the outside of the pump chamber (JP-A-10-220357).
[0005] As the second related art, a check valve including a valve
seat, a ball on the suction side of a working fluid for opening and
closing the valve seat, a stopper with an opening for limiting the
movement amount of the ball, and a joint member for assembling the
valve seat and the stopper into one piece is known as a check valve
in a fluid flow pass for sucking the working fluid into a pump
chamber and allowing the working fluid to circulate only in one
direction in discharging the working fluid into the outside of the
pump chamber. Further, the check valve is pressed against and fixed
to a pump case by a press member. A pump including a pair of the
check valves on the suction side and the discharge side of the
working fluid is also known (JP-A-2000-2350).
[0006] Further, as the third related art, a check valve made up of
a valve seat formed in a pump housing, a ball for opening and
closing the valve seat, a ball stopper for limiting the movement
amount of the ball, and a coil spring for pressing the ball against
the valve seat and a pump including the check valve are known
(JP-A-2001-173816).
[0007] However, in the invention described in JP-A-10-220357, when
the pump valve seat unit includes the suction side check valve and
the discharge side check valve, the size in the plane direction
increases. Since the pump valve seat unit is sandwiched between the
pump suction and discharge unit, and the pump actuator unit via the
O ring and is fixed, the pump performance may become unstable
because the pump chamber space area is not constant.
[0008] Further, the sealing property of the O ring can degrade with
the use of the O ring for a long term. Also, it is inconvenient to
replace the O ring at regular time intervals and the inconvenient
to consider the chemical resistance depending on the type of
working fluid and change the material of the O ring.
[0009] The pump valve seat unit is molded of a synthetic resin and
the suction side check valve has a structure wherein a separation
section of a suction section and a discharge section of fluid
floats above the pump chamber. Thus, when the actuator is driven,
the pump valve seat unit becomes deformed and a predetermined
pressure in the pump chamber cannot be provided. The valve seat
also wears as working fluid flows and a flaw can easily occur
because of cavitation, etc., which causes insufficient
durability.
[0010] In the invention described in JP-A-2000-2350, the ball is
included in the space provided between the valve seat and the
stopper, and moves in the space, to thereby open and close the
valve seat. However, the gap between the ball guide wall of the
stopper and the ball is small, and movement of the ball is hindered
because of contact resistance. Since there is rapid change in the
opening width on the seating face of a working fluid outflow
section of the valve seat, a vortex may occur which inhibits the
smooth flow of the working fluid.
[0011] Since the ball is molded of cemented carbide or ceramics,
and the weight per unit volume is larger than that of a general
working fluid, the ball is hard to move when opening and closing
the valve seat. Thus, the check valve is unsuitable for a small
pump for making the working fluid flow out at a high frequency
using a diaphragm, for example.
[0012] Further, in the invention described in JP-A-2001-173816, the
check valve has a structure wherein the ball is pressed against the
valve seat side by a coil spring at all times and the valve seat is
opened with the pressure of the working fluid, and is closed by the
elastic force of the coil spring. Thus, the inflow pressure into a
fluid inflow path requires a considerable size for the elastic
force of the coil spring and the weight of the ball, and it is
difficult to adopt the check valve as a small check valve for
opening and closing the valve seat based on the inertance value
difference between the inlet flow pass and the outlet flow pass of
working fluid, for example.
[0013] In such a pump, a coil spring is included in the flow pass
of the working fluid in the check valve and thus the flow of the
working fluid is inhibited by the coil spring. Further, the fluid
flow pass is curved rapidly from the check valve and thus the flow
resistance of the working fluid increases.
[0014] It is therefore an object of the invention to provide a
check valve which has a simple structure and a good assembly
property that can be provided at low cost. It is also an object of
the present invention to provide a small, durabile, and
high-performance pump including the check valve.
SUMMARY OF THE INVENTION
[0015] A check valve of the invention includes a tubular valve seat
frame, a valve seat that is fixedly secured to the inside of the
valve seat frame and that has a communication hole through which a
working fluid flows, and a valve body that is on the working fluid
outflow side of the valve seat for opening and closing the valve
seat, wherein the valve seat frame, the valve seat, and the valve
body are put into one unit.
[0016] According to the invention, the check valve is made up of at
least the three parts of the valve seat, the valve seat frame, and
the valve body and thus has a simple structure with a small number
of components. As such, the check valve can be manufactured at low
cost. Since the check valve is put into a unit, performance
management can be conducted in a single unit. When the check valve
is built in a pump, stable performance of the check valve can be
provided without adjusting or inspecting the check valve. The check
valve can be built in the pump without touching the valve body or
the communication hole of the valve seat so that a good assembly
property is provided and predetermined performance can be provided
without causing damage to or deforming the check valve during
assembly.
[0017] The need for providing an O ring as a sealing member on the
periphery of the check valve as in the related art described above
is eliminated. The sealing property of the O ring can be degraded
with the use of the O ring for a long term and the inconvenience of
the need for replacing the O ring at regular time intervals is
involved. However, the structure of the present invention
eliminates the inconvenience of the need for replacing the O ring
at regular time intervals, and the inconvenience of considering the
chemical resistance depending on the type of working fluid and
changing the material of the O ring are eliminated.
[0018] Further, the invention is characterized in that the valve
seat is formed of a material having higher hardness than that of
the valve seat frame, and that of the valve body.
[0019] For example, hard metal of cemented carbide, etc., or
ceramics can be adopted as the material of the valve seat. As the
ceramics, polycrystalline sinter material such as Al.sub.2O.sub.3
is representative, but single-crystal material can also be
adopted.
[0020] According to the invention, since materials have high
hardness, shock or cavitation caused by opening and closing the
valve body can be prevented from causing wear in, or damage to, the
valve seat.
[0021] Further, wear caused by the flow of the working fluid can be
prevented. Consequently, good performance can be maintained over a
long term.
[0022] The invention is characterized in that the valve body is
made up of a fixing part and an opening-closing part, and is
provided on the side of the valve seat where the working fluid
flows out and the fixing part is fixedly secured to the valve seat
frame.
[0023] For example, welding, adhesion, brazing, etc., can be
adopted as means for fixedly securing the valve body.
[0024] In such a structure, the flow resistance of the working
fluid is small and a smooth flow can be conducted as compared with
the structure wherein the valve body is provided on the side where
the working fluid flows into the valve seat. Since the fixing part
of the valve body is fixedly secured to the valve seat frame, and
the valve body does not move, the communication hole of the valve
seat can be opened and closed reliably.
[0025] The invention is characterized in that the working fluid
outflow side end face of the valve seat and an end face of the
valve seat frame are roughly at the same height, and that the
fixing part is fixedly secured to the top face of the valve seat
frame.
[0026] In doing so, the end face positions of the valve seat and
the valve seat frame are set roughly the same, so that the
opening-closing part and the fixing part of the valve body are
formed of a flat plate or plate-like member, and the shape and
dimensions of each part are easily managed. Thus, the cost can be
reduced and predetermined performance can be ensured.
[0027] The valve body is made up of a fixing part on the periphery,
an opening-closing part of the communication hole of the valve
seat, and a support part for concatenating the opening-closing part
and the fixing part. The valve body is placed in a tubular
projection provided on the periphery of the valve seat frame, and
the fixing part is fixedly secured by deforming the projection.
[0028] According to the above structure, the projection of the
valve seat frame is deformed. that is it is crimped fully or
partially (the member is deformed and fixed), whereby the fixing
part of the valve body is fixed to the valve seat frame so that the
valve body can be fixed in a small space reliably. The outer
peripheral part of the fixing part of the valve body is also fixed,
whereby the valve body can be fixed without deforming the
opening-closing part or the support part. The valve body is simply
placed in the projection of the valve seat frame, whereby the
position in the plane direction is regulated so that the
opening-closing part can open and close the working fluid
communication hole of the valve seat reliably without using any
special jig.
[0029] The invention is also characterized in that the valve body
is placed in a projection provided on the periphery of the valve
seat frame and a ring-like fixing member is press-fitted into the
projection of the valve seat frame, whereby the valve body is
sandwiched between the valve seat frame and the fixing member.
[0030] In doing so, the fixing part provided on the periphery is
sandwiched between the valve seat frame and the fixing member in
the thickness direction and is fixed so that the valve body can be
fixed without producing internal stress in the valve body and thus
can be fixed without deforming the support part or the
opening-closing part.
[0031] The invention is also characterized in that a tubular
projection is provided on the periphery of a fixing part of the
valve body and is placed in a projection of the valve seat frame
and a ring-like fixing member is press-fitted into the projection
of the valve body, whereby the valve body is sandwiched between the
valve seat frame and the fixing member.
[0032] According to the structure, the fixing member is
press-fitted into the projection provided on the valve body,
whereby the projection of the valve body is sandwiched between the
projection of the valve seat frame and the fixing member so that
the advantages similar to those described above can be provided. In
addition, the valve body is provided with the projection on the
periphery, whereby even if a thin plate of about 20 .mu.m, for
example, is used, the outer peripheral portion is reinforced so
that it is hard to bend and is less deformed during handling.
[0033] Since the valve body can be manufactured by press working,
etc., the step for providing the projection is not required and the
cost is not increased either.
[0034] The invention is also characterized in that a tubular
projection provided on the periphery of a fixing part of the valve
body is press-fitted into a radial gap between the valve seat and
the valve seat frame, and is sandwiched therebetween.
[0035] According to such a structure, the valve seat is inserted
into the projection of the valve body and the valve body and the
valve seat are press-fitted into the ring of the valve seat frame,
whereby the valve body, the valve seat, and the valve seat frame
can be one piece without using the fixing member. Since the valve
seat frame need not be provided with the projection as described
above, the structure can be made still simpler.
[0036] The invention is also characterized in that the valve body
is placed in a recess part provided on the valve seat frame so that
it can move in a thickness direction, and that a ring-like fixing
member for the valve body to support the communication hole so as
to be able to open and close the communication hole is provided on
the recess part periphery of the valve seat frame.
[0037] In doing so, the valve body is regulated at the position in
the plane direction by the recess part provided in the valve seat
frame and the range of motion in the thickness direction is also
regulated by the fixing member. Thus, the diameter and the depth of
the recess part can be set appropriately for regulating so that the
communication hole of the valve body can be opened and closed
properly. Here, the fixing member can be fixed to the recess part
periphery of the valve seat frame by face joint means of adhesion,
welding, etc. It can also be fixed as a new recess part of a larger
diameter than the recess part of the valve seat frame is provided
so that the ring-like fixing member can be press-fitted into the
recess part.
[0038] The invention is also characterized in that the valve body
is made up of a fixing part on the periphery, an opening-closing
part roughly at the center, and a plurality of blade parts for
concatenating the opening-closing part and the fixing part.
[0039] The valve body of the structure is formed roughly like a
propeller having blade parts, for example As the blade part shape,
the astern plane is provided in the valve seat direction and the
ahead plane is provided in its opposite direction.
[0040] As such, a plurality of blade parts are provided. When the
working fluid flows out, the working fluid can flow out from the
space between the blade parts in a small resistance state along the
astern plane of the moderate curved face of the blade part. When
the communication hole is closed, the working fluid presses the
ahead plane, whereby the communication hole can be closed by the
opening-closing part, and the communication hole can be opened and
closed following small motion of the diaphragm.
[0041] The invention is also characterized in that the valve seat
is formed with a plurality of communication holes, and that
opening-closing parts of the valve body are provided in a
one-to-one correspondence with the communication holes.
[0042] The plurality of communication holes can be provided in a
circle, in a line, or in parallel.
[0043] According to the present invention, the valve seat is formed
with a plurality of communication holes for the working fluid, and
the opening-closing parts of the valve body for opening and closing
the communication holes are provided separately, but the check
valve can be formed without increasing the number of components
because the fixing part on the outer periphery is formed in one
piece. For example, if the amplitude of the diaphragm is about 10
.mu.m in a diaphragm type pump, the operation range of the
opening-closing part of the valve body is about 20 .mu.m. Thus, to
increase the flow amount of working fluid, a plurality of
communication holes can be provided for increasing the flow
amount.
[0044] Although one opening-closing part can also open and close
the plurality of communication holes, it is considered that it is
impossible to open and close all the communication holes in a
uniform manner because of the slight deformation or dimensional
variation of the opening-closing part. As separate opening-closing
parts are provided in a one-to-one correspondence with the
communication holes, all the communication holes can be opened and
closed reliably.
[0045] The invention is also characterized in that the working
fluid communication hole of the valve seat is opened like an
ellipse.
[0046] In such a structure, the opening area can be set large and
the flow amount of working fluid can be increased.
[0047] Preferably, an inlet and an outlet of the communication hole
of the valve seat are smoothly rounded to decrease fluid resistance
of the working fluid.
[0048] Further, the invention is also characterized in that the
pass between an inlet and an outlet of the communication hole is
formed smoothly as a continuous, roughly circular arc.
[0049] In doing so, the communication hole of the valve seat has a
small diameter as compared to the outside of the inlet. As such,
when the working fluid flows into the communication hole or flows
through the inside of the communication hole, the flow resistance
is increased.
[0050] Therefore, according to the invention, the inlet and the
outlet are smoothly rounded, whereby the inflow resistance when
working fluid flows into the communication hole can be decreased
and the flow resistance caused by a vortex occurring when working
fluid flows out can be decreased.
[0051] Further, the inside of the communication hole is also formed
to have a shape like a roughly circular arc that is smoothly
continuous to the inlet and the outlet so that the flow resistance
in the communication hole can be decreased.
[0052] The invention is also characterized in that the face of the
valve seat on the side into which the working fluid flows is formed
like a funnel as a slope or a roughly circular arc continuous to
the inlet.
[0053] If such a shape is adopted, the resistance when the working
fluid flows into the communication hole of the valve seat can be
decreased.
[0054] More preferably, the funnel shape of a roughly circular arc
is made such that a midpoint on the cross section of the inner face
slightly swells rather than a letter U of the inner face shape.
[0055] Preferably, the face of the valve body in contact with the
outlet periphery of the communication hole is formed like a dome or
a cone.
[0056] In the structure, if the valve body comes in contact with
the periphery of the communication hole of the valve seat on a
plane, the shape of the valve body is simple and the valve body can
be easily manufactured. And if the opening-closing part is shaped
like a dome or a cone, contact with the valve seat becomes linear
contact pressure is increased, and leakage of the working fluid can
be prevented.
[0057] The check valve of the invention is characterized in that
the valve body for opening and closing the valve seat is a ball.
The check valve further includes a ball support member for
supporting the ball and is formed with a communication hole for the
working fluid. The valve seat frame, the valve seat, the ball, and
the ball support member are also put into a unit.
[0058] Preferably, the ball is a sphere.
[0059] According to the invention, the check valve comprises the
valve seat, the valve seat frame, the ball, and the ball support
member. Thus, the number of components is small, and each component
has a simple shape so that the check valve can be manufactured
easily, shape management is easy to conduct, and the check valve
can be manufactured at low cost. Since the check valve is put into
a unit, performance management can be conducted in a single unit as
the check valve and, for example, when the check valve is built in
a pump, stable performance of the check valve can be provided
without adjusting or inspecting the check valve. Further, the check
valve can be built in the pump, etc., without touching the ball or
the communication hole of the valve seat so that predetermined
performance can be provided without causing damage to or deforming
the check valve during assembly.
[0060] Since the valve seat is opened and closed by the ball, when
the valve seat is open, working fluid flows on the surface of the
ball and thus the flow resistance is small. For example, as
compared to a case where a plate-like valve is used, when the ball
leaves the valve seat for opening the communication hole, even if
the move distance is the same, the flow cross-sectional area
becomes large so that the flow amount can be increased. When the
valve seat is hermetically sealed, the valve seat and the ball come
in line contact with each other, the contract pressure increases,
and the valve seat can be hermetically sealed reliably.
[0061] The invention is also characterized in that the ball support
member is made up of a support part on the periphery, a
communication hole roughly at the center where working fluid flows,
a ball support part for supporting the ball, and an arm-like joint
part for joining the support part and the ball support part.
[0062] In the invention, the ball support part for supporting the
ball is configured as described above so that it can be formed
easily of a metal plate material by means of pressing, etc., for
example. The center of the ball from the communication hole of the
ball support member, and further the peripheral part from the
opening between the joint parts, are pushed up by the working
fluid, and the ball presses the communication hole of the valve
seat for hermetically sealing the communication hole. Thus, the
ball easily moves by the pressure of the working fluid, and the
communication hole of the valve seat can be hermetically sealed
reliably.
[0063] When the ball leaves the valve seat and the valve seat is
opened, the ball is regulated at the position and is supported by
the ball support part of the ball support member so that the ball
can be supported at the appropriate position with a small space and
in a simple shape.
[0064] Further, since the ball rotates at the moving time, the
contact position of the ball with the valve seat changes each time
and thus the contact position with the valve seat changes, so that
wear at the same position can also be prevented.
[0065] The invention is also characterized in that a claw part for
supporting the ball is projected to the ball support part.
[0066] In the above structure, the ball is supported by three
radially projected claw parts, provided in the ball support part so
that the position of the ball can be regulated reliably. The claw
parts support the ball in a range smaller than the diameter of the
ball and thus do not hinder flow of the working fluid.
[0067] Preferably, when the valve seat is opened or closed, the
ball and the ball support member move at the same time or
separately, whereby the valve seat is opened or closed.
[0068] In doing so, the ball and the ball support member, and the
ball support member and the valve seat frame, are supported, but
not fixed. Therefore, as only the ball moves, the communication
hole of the valve seat can be opened and closed; the ball can be
pushed up by the ball support member for hermetically sealing the
communication hole; and the ball and the ball support member can
move together for opening the communication hole. Because of the
structure wherein not only the ball, but also the ball support
member can move, the ball support member can also receive positive
pressure of the pump chamber and press the ball so that the
hermetic sealing force of the communication hole can be
enhanced.
[0069] Preferably, the ball support part of the ball support member
is provided with an elastic part for pressing the ball against the
valve seat.
[0070] As described above, the ball opens and closes the
communication hole and since the ball support part is provided with
the elastic part, the ball can be pressed against the communication
hole by the elastic force for hermetically sealing the
communication hole reliably. More preferably, the elastic force of
the elastic part is set to a magnitude such that the ball can be
opened by the negative pressure of the pump chamber when the
communication hole is opened.
[0071] If the ball is brought into contact with the communication
hole of the valve seat at all times by the elastic part, when the
pump is stopped, the working fluid can be prevented from flowing
out.
[0072] The check valve of the invention is also characterized in
that on the periphery of an outer periphery support part of the
ball support member, a tubular side guide part is provided along
the inner face of a hole made in the valve seat frame.
[0073] In the above structure, as compared to a case where the ball
support member is formed like a plate, the ball support member is
provided with the tubular side guide part, and the side guide part
moves along the inner face of the hole of the valve seat frame so
that a smooth move is made without being inclined in the
cross-sectional direction, and the communication hole can be opened
and closed reliably. If such a side guide part is provided, the
space of the check valve need not be increased.
[0074] The invention is also characterized in that an average value
of the density of the ball and a density of the working fluid are
roughly the same.
[0075] The ball for opening and closing the communication hole
moves with a change in the pressure of the working fluid. Since the
average value of the density of the ball and the density of the
working fluid are made roughly the same, the ball is in a floating
state or in a state close to the floating state of the working
fluid if driving of the pump is stopped. Thus, if the pump is
driven, the ball moves due to a slight pressure change of the
working fluid so that if the drive source of the pump is driven at
a high frequency, like a piezoelectric element, the ball moves in
synchronization with the drive frequency and can open and close the
valve seat.
[0076] Further, the invention is characterized in that the ball is
hollow.
[0077] Considering durability, a metal such as an iron-based alloy,
a stainless alloy, a copper-based alloy, or an aluminum alloy, or
glass, ceramics, a synthetic resin, etc., can be adopted as the
material of the ball.
[0078] If the ball is formed of any of the above materials, the
weight per unit volume of the ball is large and the ball will be
hard to move if a slight pressure change of the working fluid is
made. If the ball is made hollow, however, the weight per unit
volume of the ball can be decreased, and the thickness of the outer
shell of the ball can be adjusted according to the material of the
ball and the material of the working fluid, whereby the weight per
unit volume of the ball can be set to roughly the same as the
weight per unit volume of the working fluid pushed away by the ball
as described above. As such, the advantages as described above can
be provided.
[0079] Further, the invention is characterized in that the ball has
a surface formed with a coating.
[0080] As the coating, a hard anodic oxide coating of cemented
carbide, nickel, chromium, ceramics, etc., can be adopted. As means
for coating the ball, a wet plating such as an electroplated
coating or a chemical plating or a dry plating such as vacuum
evaporation, sputtering, or ion plating can be adopted. A
rubber-based soft material can also be adopted.
[0081] In such a structure, the ball for opening and closing the
communication hole is formed on the outer shell with the coating.
Thus, even if the material of the ball is limited for ease of
manufacturing, if any hard anodic oxide coating described above is
selected, the hardness of the surface can be made high and thus the
ball is less worn or is less damaged by the shock of opening and
closing the communication hole although the ball is used for a long
term. If the ball is made hollow as described above, the hard
anodic oxide coating can prevent the ball from becoming
deformed.
[0082] If a soft coating is selected, the sealing property of the
valve seat can be more enhanced.
[0083] The invention is characterized in that on the outside of the
communication hole of the valve seat, an inlet and an outlet for
allowing the working fluid to flow are smoothly formed continuously
as a roughly circular arc, and that the outlet has an opening
formed as a circular arc of a larger diameter than the diameter of
the ball.
[0084] Thus, the communication hole has an inlet and an outlet made
continuous as a smooth circular arc so that the fluid resistance
when the working fluid flows through the valve seat can be
decreased. Particularly, the outlet is opened and closed by the
ball and thus when the outlet is formed on the outside of the
opening with a larger circular arc than the diameter of the ball,
even when the ball is brought slightly away from the valve seat,
the cross-sectional area of the opening where the working fluid
flows out can be wide so that the outflow amount of the working
fluid can be increased. This also provides the effect of bringing
the ball away from the valve seat.
[0085] The ball moves to the communication hole along the surface
of the circular arc provided on the outside of the opening of the
outlet and hermetically seals the communication hole. Thus, if the
ball moves and the plane direction position of the ball varies
slightly, the ball can hermetically seal the communication hole
more reliably.
[0086] Further, the invention is characterized in that the ball
support member is fixedly secured to the valve seat frame.
[0087] If the ball support member is fixedly secured to the valve
seat frame, the ball opens and closes the communication hole
solely. But if the ball is regulated at a position in the plane
direction by the ball support part of the ball support member, the
position of the ball relative to the communication hole of the
valve seat can be regulated more precisely.
[0088] Because of the above structure, wherein only the ball moves,
a check valve of a simple structure can be provided as compared to
a structure wherein the ball support member moves.
[0089] The invention is also characterized in that on the side of
the valve seat frame between the valve seat and the ball support
member, a hole that is pierced from the inside to the outside is
made.
[0090] It should be noted that although the valve seat, the valve
seat frame, the ball, and the ball support member are put into a
unit as described above, the through hole is made in the side of
the valve seat frame so that the position and motion of the ball
can be checked through the hole in the single unit of the check
valve.
[0091] If the check valve is clogged with the working fluid, the
check valve can also be removed from the pump for allowing, for
example, a cleaning fluid, etc., to flow through the hole for
cleaning the inside of the check valve.
[0092] A pump of the invention includes a pump chamber whose volume
can be changed by a piston or a diaphragm; an inlet flow pass for
allowing the working fluid to flow into the pump chamber; and an
outlet flow pass for allowing the working fluid to flow out from
the pump chamber. The pump further includes an actuator for driving
the diaphragm and a cabinet for supporting the actuator. A pump of
the present invention is also characterized in that a check valve
as described in any of the above embodiments can be included
between the inlet flow pass and the pump chamber.
[0093] The pump includes the check valve as described above and
thus has advantages in that it is small, has a simple structure,
can be manufactured at low cost, allows the working fluid to flow
smoothly, and is durable. Particularly, the advantages described
above are noticeable in a small pump wherein the inertance of the
outlet flow passage is larger than that of the inlet flow pass, and
the pressure applied to the valve seat is large. The check value of
the present invention is particularly effective for a small pump of
a diaphragm type, etc., and the pump can be used for a cooling
device of an electronic machine such as a projector, a water jet
knife, a fluid actuator, a power source of a piston of a
microhydraulic press, etc. It should be noted, however, that the
present invention is not limited to the above uses.
BRIEF DESCRIPTION OF THE DRAWINGS
[0094] FIG. 1 is a sectional view showing a pump according to a
first embodiment of the invention;
[0095] FIG. 2 is a sectional view showing a check valve according
to the first embodiment of the invention;
[0096] FIG. 3 is a plan view showing a valve body according to the
first embodiment of the invention;
[0097] FIG. 4 is a plan view showing another valve body according
to the first embodiment of the invention;
[0098] FIG. 5 is a plan view showing another valve body according
to the first embodiment of the invention;
[0099] FIG. 6 is a plan view showing another valve body according
to the first embodiment of the invention;
[0100] FIG. 7 is a sectional view showing a valve seat according to
the first embodiment of the invention;
[0101] FIG. 8 is a sectional view showing another valve seat
according to the first embodiment of the invention;
[0102] FIG. 9 is a graph showing the relationship between pressure
in a pump chamber and displacement of a diaphragm according to the
first embodiment of the invention;
[0103] FIG. 10 is a graph showing the relationship between the
waveforms of the flow amounts in an inlet flow pass and an outlet
flow pass according to the first embodiment of the invention;
[0104] FIG. 11 is a sectional view showing a check valve according
to a second embodiment of the invention;
[0105] FIG. 12 is a sectional view showing a check valve according
to a third embodiment of the invention;
[0106] FIG. 13 is a sectional view showing a check valve according
to a fourth embodiment of the invention;
[0107] FIG. 14 is a perspective view showing a valve body according
to the fourth embodiment of the invention;
[0108] FIG. 15 is a sectional view showing a check valve according
to a fifth embodiment of the invention;
[0109] FIG. 16 is a sectional view showing a check valve according
to a sixth embodiment of the invention;
[0110] FIG. 17 is a sectional view showing a modification of the
check valve according to the sixth embodiment of the invention;
[0111] FIG. 18 is a plan view showing a valve body according to the
sixth embodiment of the invention;
[0112] FIG. 19 is a plan view showing another valve body according
to the sixth embodiment of the invention;
[0113] FIG. 20 is a plan view showing another valve body according
to the sixth embodiment of the invention;
[0114] FIG. 21 is a side view showing another valve body according
to the sixth embodiment of the invention;
[0115] FIG. 22 is a sectional view showing a check valve according
to a seventh embodiment of the invention;
[0116] FIG. 23 is a plan view showing a valve body according to the
seventh embodiment of the invention;
[0117] FIG. 24 is a sectional view showing a check valve according
to an eighth embodiment of the invention;
[0118] FIG. 25 is a plan view showing the check valve according to
the eighth embodiment of the invention;
[0119] FIG. 26 is a plan view showing a valve body according to a
ninth embodiment of the invention;
[0120] FIG. 27 is a plan view showing another valve body according
to the ninth embodiment of the invention;
[0121] FIG. 28 is a sectional view showing a check valve according
to a tenth embodiment of the invention;
[0122] FIG. 29 is a plan view showing a ball support member of the
check valve according to the tenth embodiment of the invention;
[0123] FIG. 30 is a sectional view showing a modification of the
ball support member of the check valve according to the tenth
embodiment of the invention;
[0124] FIG. 31 is a sectional view showing a valve seat of the
check valve according to the tenth embodiment of the invention;
[0125] FIG. 32 is a sectional view showing a ball of the check
valve according to the tenth embodiment of the invention;
[0126] FIG. 33 is a sectional view showing a ball of a check valve
according to an eleventh embodiment of the invention;
[0127] FIG. 34 is a sectional view showing a check valve according
to a twelfth embodiment of the invention;
[0128] FIG. 35 is a plan view showing a ball support member of the
check valve according to the twelfth embodiment of the
invention;
[0129] FIG. 36 is a sectional view showing a check valve according
to a thirteenth embodiment of the invention;
[0130] FIG. 37 is a plan view showing a ball support member of the
check valve according to the thirteenth embodiment of the
invention;
[0131] FIG. 38 is a plan view showing a ball support member of a
check valve according to a fourteenth embodiment of the
invention;
[0132] FIG. 39 is a sectional view showing the ball support member
of the check valve according to the fourteenth embodiment of the
invention;
[0133] FIG. 40 is a sectional view showing a check valve according
to a fifteenth embodiment of the invention; and
[0134] FIG. 41 is a sectional view showing a check valve according
to another embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
[0135] Check valves and pumps including the check valves according
to the invention will be discussed. Embodiments described below are
only exemplary and the invention is not limited to the specific
embodiments.
[0136] To begin with, a first embodiment of the invention will be
discussed. FIGS. 1 to 10 show a check valve of the first embodiment
and a pump 10 including the check valve.
[0137] FIG. 1 is a longitudinal sectional view of the pump in which
the check valve of the first embodiment is placed. In FIG. 1, the
pump 10 includes a pump chamber unit 100 and an actuator unit
200.
[0138] The pump chamber unit 100 is made up of a pump chamber body
101 including an inlet flow pass 111 into which a working fluid is
made to flow in and an outlet flow pass 117 from which the working
fluid is made flow out, a diaphragm 150, and an elastic film 151
that may be used as pulsating flow absorption means for preventing
a pulsating flow of the working fluid.
[0139] The pump chamber body 101 has an outside shape roughly like
a cylinder in plan view. An inlet connection pipe 110 formed with
the inlet flow pass 111 projects from one side of the pump chamber
body 101, and the inlet flow pass 111 communicates with an elastic
wall chamber 112. The tip of the inlet flow pass 111 is connected
to external piping of a tube, etc., (not shown) for supplying the
working fluid. On the opposite side to the inlet connection pipe
110, an outlet connection pipe 116 formed with the outlet flow pass
117 projects. The outlet flow pass 117 has an inner end part
communicating with a pump chamber 119 and an opposite end as a
discharge port for the working fluid that is connected to an
external piping (not shown).
[0140] The elastic wall chamber 112 with which the inlet flow pass
111 communicates is formed as a cylindrical recess roughly at the
center of the pump chamber body 101. An elastic film 151 is
hermetically fixed to an opening periphery upper face 121 in an
upper portion in the figure, and an opening 113 on the pump chamber
119 side has a diameter that is set to be smaller than the inner
diameter of the elastic wall chamber 112. A check valve 50 is
placed between the opening 113 and the pump chamber 119. The check
valve 50, as a fluid resistance element, may be opened to allow the
working fluid to flow from the inlet flow pass 111 to the outlet
flow pass 117, or may be closed.
[0141] In a pump that is driven at a higher frequency than a
smaller pump that is driven at about 5 kHz, the elastic film 151
and the elastic wall chamber 112 are preferably provided, but are
not necessarily required.
[0142] A thin recess is formed on the opposite side to the elastic
wall chamber 112 with the check valve 50 between. The space
hermetically sealed by the diaphragm 150 is the pump chamber
119.
[0143] The pump chamber body 101 is preferably formed by metal
injection molding. It can also be molded using precision casting,
etc. Preferably, stainless steel, a titanium alloy, etc., is
adopted as a material because of its chemical resistance, rust
prevention, and structural strength, but an iron-based alloy or a
copper-based alloy can also be adopted.
[0144] The check valve 50 is a unit made up of a valve seat 60, a
valve seat frame 70, and a valve body 80 as can be seen with
reference to FIG. 2. The check valve 50 is pressed into an inner
wall 114 of the opening 113 and is closely fixed.
[0145] The diaphragm 150 is a disk-like, thin plate made of
stainless steel, etc., that has a thickness of about 20 .mu.m, and
has an outer peripheral portion closely fixed to the periphery of
the pump chamber 119 by means of adhesion, welding, brazing,
etc.
[0146] An upper plate 140 that is an elastic film protection member
is placed on the top face of the elastic film 151 and has an outer
peripheral portion screwed into and fixed to the pump chamber body
101 together with the elastic film 151 with a fixing screw 155.
Only one fixing screw 155 is shown in FIG. 1, but three or four
fixing screws 155 are included in the plane direction in balance.
When the working fluid pulsates, the elastic film 151 bends in the
cross-sectional direction to absorb the pulsation, but a recess, in
the range out of contact if the elastic film 151 bends, is formed
on the face side of the upper plate 140 that comes into contact
with the elastic film 151. A hole 103 for releasing air that is
hermetically sealed by the upper plate 140 and the elastic film 151
is made at the center in the plane direction.
[0147] The pump chamber body 101 is formed with a tubular part 122
projected to the outer periphery on the opposite side to the
elastic wall chamber 112 with the check valve 50 between. The
tubular part 122 has an end face that is provided with a female
screw for fixing the actuator unit 200. The diaphragm 150 for
hermetically sealing the actuator unit 200 side of the pump chamber
119 is closely fixed to the opening of the pump chamber 119 inside
the tubular part 122. The corner of the wall of the pump chamber
119 that comes into contact with the diaphragm 150 is smoothly
rounded.
[0148] A cabinet 201 of the actuator unit 200 is inserted into the
inside of the tubular part 122.
[0149] The cabinet 201 is shaped like a tube with one side closed
and an opposite side opened, and is formed with a tubular part 202
and a flange part 203 projecting in the outer direction from the
outer periphery of the tubular part. The tubular part 202 is
pressed into the inside of the tubular part 122 of the pump chamber
body 101 and is detachable.
[0150] The tubular part 202 has an end part pressing the diaphragm
150, but has an inner diameter that is sized so as not to come in
contact with an upper bed 401. The corner of the tubular part 202
that comes into contact with the diaphragm 150 is preferably
smooth. The inner diameter coming in contact with the diaphragm 150
is roughly the same as the inner diameter of the part of the pump
chamber body 101 coming in contact with the diaphragm 150.
[0151] The cabinet 201 (actuator unit 200) and the pump chamber
unit 100 are fixed by fixing screws 205 between the insertion hole
of each fixing screw 205 provided in the flange part 203 and the
female screw provided in the tubular part 122 of the pump chamber
body, and are put into one piece with sufficient strength for
allowing the pump 10 to be used.
[0152] An actuator 301 is provided inside the tubular part 202 of
the cabinet 201.
[0153] The actuator 301 is a piezoelectric element for conducting
stretching vibrations in the length direction, and has one end face
to which the upper bed 401 is fixedly secured and an opposite end
part fixedly secured to a bottom 209 of the cabinet 201.
[0154] The upper bed 401 is a disk formed of a material of a small
specific gravity such as an aluminum alloy, and the opposite face
to the adhesion face of the actuator 301 is brought into intimate
contact with the diaphragm 150. When a bias voltage is applied to
the actuator 301 from an external control circuit (not shown), the
actuator 301 conducts stretching vibrations; when the actuator 301
stretches, it presses and bends the diaphragm 150 for decreasing
the volume of the pump chamber 119. When the actuator 301
contracts, it restores the diaphragm 150 to the former state for
increasing the volume of the pump chamber 119.
[0155] The upper bed 401 can be omitted if the end area and shape
of the actuator is set appropriately.
[0156] In a side of the tubular part 202 of the cabinet 201, a
through hole 204 is made from the inside to the outside. A lead
wire for applying a bias voltage to the actuator 301 is preferably
inserted into the through hole 204, although not shown.
[0157] Here, the relation of inertance of the flow pass in the pump
of the invention will be discussed. If a pressure fluctuation
absorption element such as a soft part exists in the flow pass, the
flow pass to the pressure fluctuation absorption element may be
used to calculate the inertance. Thus, the inertance of the inlet
flow pass is the inertance of the flow pass from the elastic film
151 of the pressure fluctuation absorption element to the check
valve 50. On the other hand, the inertance of the outlet flow pass
is the inertance of the outlet flow pass 117. In a comparison
between the two types of inertance, the inertance of the outlet
flow pass is by far larger than that of the inlet flow pass.
[0158] Next, the check valve 50 according to the first embodiment
of the invention will be discussed.
[0159] FIG. 2 shows the cross-sectional shape of the check valve 50
of the first embodiment. In FIG. 2, the check valve 50 is formed of
the valve seat 60, the valve seat frame 70, and the valve body 80.
The valve seat 60 is a disk-like member having a communication hole
61 for the working fluid made at the center. An inlet 62 and an
outlet 63 for the working fluid of the communication hole 61 are
rounded smoothly. The inlet side is rounded to decrease the inflow
resistance of the working fluid and the outlet side is rounded to
decrease a vortex occurring when working fluid flows out.
[0160] A slope 64 is provided at the outer peripheral corner on the
outflow side of the valve seat 60 for setting the contact area with
the valve body 80 to a proper size, and for facilitating the press
fitting into the valve seat frame 70.
[0161] The valve seat 60 is formed of a material having higher
hardness than that of the valve seat frame 70 and the valve body
80. Preferably, a cemented carbide or a ceramic (Al.sub.2O.sub.3,
etc.,) is adopted as the material of the valve seat 60.
[0162] The valve seat frame 70 is formed like a ring having a
through hole 71 made at the center into which the valve seat 60 may
be press-fitted. The working fluid inflow side of the through hole
71 is formed to have a shape that is smoothly rounded from roughly
the same position as the height of a top face 65 in the figure of
the valve seat 60, and is continuous to a slope 72 that is wider
than the through hole 71 in the upper part. A tubular projection 74
is formed in the outer peripheral portion of the face on the
opposite side to the slope 72. The valve body 80 is placed in the
projection 74 and is fixedly secured to a bottom 73 of the
projection 74 by means of welding, adhesion, etc. The material of
the valve seat frame 70 is not limited, but a copper-based alloy is
preferably used.
[0163] The end face leading to the outlet 63 of the valve seat 60
and the bottom 73 of the valve seat frame 70 are the same height,
and the valve body 80 is joined to the valve seat 60 and the bottom
73 at the same height.
[0164] The valve seat 60, the valve seat frame 70, and the valve
body 80 are put into a unit as described above and are press-fitted
into the inner wall 114 of the opening of the pump chamber body
101.
[0165] When an opening-closing part 81 presses the valve seat 60
(indicated by the chain double-dashed line in the figure), the
valve body 80 hermetically seals the communication hole 61; when
the opening-closing part 81 is brought away from the valve seat 60
(indicated by the solid line in the figure), the valve body 80
opens the communication hole 61.
[0166] FIG. 3 is a plan view of the valve body 80 of the first
embodiment. In FIG. 3, the valve body 80 is a thin disk formed with
a slit 82 that is shaped roughly like a letter U at the center, and
includes a support part 84 for concatenating the opening-closing
part 81 and a peripheral fixing part 83.
[0167] The support part 84 and the opening-closing part 81 are
formed thinner than the fixing part 83 (although not shown) for
enhancing the fixing strength of the fixing part 83, and enabling
easy opening and closing of the support part 84 and the
opening-closing part 81 following stretch and contraction of the
diaphragm 150.
[0168] Stainless steel, etc., is preferably adopted as the material
of the valve body 80.
[0169] Various shapes can be adopted for the valve body 80 in
addition to that shown in FIG. 3, and modifications of the valve
body 80 will be discussed with reference to FIGS. 4 to 6.
[0170] FIG. 4 is a plan view showing one of the modifications of
the valve body 80 of the first embodiment. In FIG. 4, a valve body
80 is formed with a slit 82 that is shaped roughly like a horseshoe
at the center, and includes a support part 84 for concatenating an
opening-closing part 81 and a peripheral fixing part 83. The
support part 84 is constricted narrower than the opening-closing
part 81. As the width is thinned, the elastic force is adjusted and
opening and closing of the opening-closing part 81 are
facilitated.
[0171] FIG. 5 is a plan view showing another modification of the
valve body 80 of the first embodiment. In FIG. 5, a valve body 80
is formed with an opening-closing part 81 at the center and an
outer peripheral ring-like fixing part 83. The opening-closing part
81 is concatenated by three support parts 84 that extend radially.
The support parts 84 bend in the thickness direction following the
above-described diaphragm 150, thereby opening and closing the
communication hole 1.
[0172] A further modification of the valve body 80 described with
reference to FIG. 5 will be discussed with reference to FIG. 6.
[0173] FIG. 6 is a plan view showing a modification of the valve
body 80. The embodiment shown in FIG. 6 differs from the valve body
80 described with FIG. 5 only in that a curve is contained at a
midpoint of each support part 84 that concatenates an
opening-closing part 81 and a fixing part 83. Each support part 84
contains the curve part so that the move distance in the thickness
direction of the opening-closing part 81 is large, and the elastic
coefficient of each support part 84 is small for easy bending.
[0174] Next, modification of the valve seat 60 shown in the first
embodiment (see FIG. 2) will be discussed with reference to FIGS. 7
and 8.
[0175] FIGS. 7 and 8 are sectional views showing the shape of the
valve seat 60. In FIG. 7, the valve seat 60 is a disk-like member
having a communication hole 61 for the working fluid made at the
center, and an inlet 62 and an outlet 63 for the working fluid of
the communication hole 61 are smoothly rounded (indicated by
numerals 67 and 68 in the figure). The inlet side is rounded to
decrease the inflow resistance of the working fluid, and the outlet
side is rounded to decrease a vortex occurring when the working
fluid flows out.
[0176] The communication hole 61 concatenating the round parts 67
and 68 of the inlet 62 and the outlet 63 is formed with a shape
including smooth circular arcs so that the center in the
cross-sectional direction becomes narrow for decreasing the fluid
resistance when the working fluid rapidly flows into the narrow
communication hole 61 from the opening 113 of the pump chamber body
101 (see FIG. 1).
[0177] In the peripheral portion of the outlet 63, a slope 64 is
formed from a flat portion 66 to the outer peripheral portion. The
area of the flat portion 66 is set to a size such that the
opening-closing part 81 of the valve body 80 is brought into
contact with the flat portion 66, and such that the working fluid
easily flows out at the opening time. If the heights surrounding
the outlet are uniform, no flat portion 66 may be provided.
[0178] FIG. 8 is a sectional view of a valve seat showing a
modification of the valve seat 60 described with reference to FIG.
7. In FIG. 8, a valve seat 60 has a top face 65 (see FIG. 7) which
is not a plane, and is formed with an introduction part 69 of the
working fluid concatenated as continuous circular arcs from an
inlet 62 to the outer periphery. The introduction part 69 is shaped
like a funnel for introducing the working fluid from the opening
113 of the pump chamber body 101 into a communication hole 61 with
the fluid resistance lessened.
[0179] The introduction part 69 may be formed as a linear slope.
Any of the shapes can be selected appropriately from the
relationship between the diameter of the opening 113 and the
communication hole 61.
[0180] Subsequently, the drive operation of the pump 10 of the
invention will be discussed.
[0181] FIG. 9 is a graph showing the relationship between pressure
in the pump chamber 119 and displacement of the diaphragm 150. A
description is given also with reference to FIG. 1. First, a bias
voltage is supplied to the actuator 301, whereby the diaphragm 150
vibrates and the volume of the pump chamber 119 changes
continuously. Waveforms of pressure (atmospheric pressure) in the
pump chamber 119 are indicated as gage pressure and displacement of
the diaphragm 150 (.mu.m) in a state in which the discharge flow
amount of the working fluid is large as the pump is operated with
the load pressure of the pump 10 set to 1.5 atmospheres are shown.
In the displacement waveform of the diaphragm 150, the area in
which the inclination of the waveform is positive is the process in
which the actuator 301 stretches for decreasing the volume of the
pump chamber 119. On the other hand, the area in which the
inclination of the waveform is negative is a process in which the
actuator 301 contracts for increasing the volume of the pump
chamber 119.
[0182] When the volume decreasing process of the pump chamber 119
starts, the pressure in the pump chamber 119 starts to rise. Before
the volume decreasing process terminates, the pressure attains the
maximum value and starts to decrease for reasons described later.
Further, when the volume decreasing process of the pump chamber 119
starts, the pressure continues to decrease and a vacuum state
occurs in the pump chamber 119 and the pressure becomes a constant
value of -1 atmosphere, as gage pressure.
[0183] FIG. 10 is a graph of the relationship between the waveforms
of the flow amounts in the inlet flow pass 111 and the outlet flow
pass 117. The flow amount in the forward direction (load direction)
when the pump 10 is operated is in the positive direction on the
graph.
[0184] When the pressure in the pump chamber 119 starts to rise and
exceeds the load pressure, the flow amount in the outlet flow pass
117 starts to increase. The working fluid in the pump chamber 119
starts to flow out from the outlet flow pass 117 and the pressure
in the pump chamber 119 starts to decrease at the point at which
the outflow amount exceeds the volume decrease amount of the pump
chamber 119 caused by displacement of the diaphragm 150. When the
pressure in the pump chamber 119 decreases and falls below the load
pressure, the flow amount in the outlet flow pass 117 starts to
decrease. The flow amount change rate is almost equal to the value
resulting from dividing the pressure difference between the
pressure in the pump chamber 119 and the load pressure by the
inertance value of the outlet flow pass 117.
[0185] On the other hand, in the inlet flow pass 111, when the
pressure in the pump chamber 119 decreases lower than the
atmospheric pressure, the pressure difference causes the check
valve 50 to be opened, which increases the flow amount. When the
pressure in the pump chamber 119 increases higher than the
atmospheric pressure, the flow amount starts to decrease. The flow
amount change rate is almost equal to the value resulting from
dividing the pressure difference between the pressure in the pump
chamber 119 and the pressure before the inlet flow pass by the
inertance value of the inlet flow pass 111, in a similar manner to
that described above, for the time period over which the check
valve 50 is opened. Backward flow is prevented by the backflow
prevention function of the check valve 50.
[0186] In the first embodiment, the check valve 50 is made up of
the valve seat 60, the valve seat frame 70, and the valve body 80.
Thus, the check valve 50 has a simple structure with a small number
of components so that the check valve 50 can be manufactured at low
cost. Since the check valve 50 is put into a unit, performance
management can be conducted in a single unit. When the check valve
50 is built in the pump 10, stable performance can be provided
without again adjusting or inspecting the check valve 50. The check
valve 50 can be built in the pump 10 without touching the valve
body 80 or the communication hole 61 of the valve seat 60 so that
predetermined performance can be provided without causing damage to
or deforming the check valve 50 at the assembling time.
[0187] An O ring, etc., as a sealing member need not be provided on
the periphery of the check valve 50. As such, the inconvenience of
replacing the O ring at regular time intervals as the sealing
property of the O ring degrades after use of the O ring for a long
term, and the inconvenience of considering the chemical resistance
depending on the type of the working fluid and the material of the
O ring are eliminated.
[0188] In the first embodiment, the valve body 80 is placed on the
side of the valve seat 60 where the working fluid flows out, and is
fixedly secured to the valve seat frame 70. In this manner, the
valve body 80 causes less flow resistance of the working fluid and
a smooth flow can be conducted as compared with a structure wherein
the valve body 80 is placed on the side where the working fluid
flows into the valve seat 60.
[0189] The fixing part 83 of the valve body 80 fixed to the valve
seat frame 70 has an area where the structural strength is larger
than that in any other portion. The support part 84 is formed to
have a shape that has elasticity which enables vibration, and the
opening-closing part 81 is formed to have a shape and thickness
that easily comes into contact with the valve seat 60. Accordingly,
the valve body 80 is formed in one piece while having different
functions so that the valve body 80 can be easily manufactured, and
the shapes and dimensions of the parts can be easily managed. Thus,
the cost can be reduced and predetermined performance can be
ensured.
[0190] Since the communication hole 61 of the valve seat 60 has a
small diameter as compared to the opening 113 of the pump chamber
body 101, when the working fluid flows into or through the
communication hole 61, the flow resistance increases. Therefore, as
the inlet 62 and the outlet 63 are rounded smoothly, the inflow
resistance when the working fluid flows in can be decreased, and
the flow resistance caused by a vortex occurring when the working
fluid flows out can be decreased.
[0191] Further, the inside of the communication hole 61 is also
formed like a smoothly continuous circular arc to the inlet 62 and
the outlet 63, whereby the flow resistance in the communication
hole 61 can be decreased.
[0192] Further, in the first embodiment, the working fluid
introduction part 69 of the valve seat 60 is formed like a funnel
having a slope or a roughly circular arc that is continuous to the
inlet 62 so that any resistance that occurs when the working fluid
flows into the communication hole 61 of the valve seat 60 can be
decreased.
[0193] In the first embodiment, the valve seat 60 is formed of a
material having a higher hardness as compared to that of the valve
seat frame 70 and the valve body 80. For example, the valve seat 60
may be formed of materials such as a hard metal of cemented
carbide, or a ceramic so that shock or cavitation caused by opening
and closing the valve body 80 can be prevented from causing wear
in, or damage to, the valve seat 60. Further, wear caused by the
flow of the working fluid can be prevented. Consequently, good
performance can be maintained over a long term.
[0194] Since the pump of the invention is vibrated at a high
frequency by the actuator 301 and the check valve 50 is small, the
pressure per unit area becomes high. As such, a pump including the
check valve 50 described above is excellent in durability, is
small, and has a simple structure that can be provided at low
cost.
[0195] In the description of the first embodiment, as the means for
changing the volume of the pump chamber 119, a diaphragm 150 is
taken as an example. However, the check valve of the invention can
also be used in a pump that includes a piston rather than a
diaphragm, and still provide similar advantages.
[0196] FIG. 11 is a sectional view showing a check valve 50 of the
second embodiment of the invention. In the second embodiment, the
fixed structure of the valve body 80 to the valve seat frame 70
described in the first embodiment (see FIG. 2) is changed, and only
this difference will be discussed. Functional members identical
with those of the first embodiment are denoted by the same
reference numerals in FIG. 11.
[0197] In FIG. 11, a valve seat 60 is press-fitted into a valve
seat frame 70. A tubular projection 74 is formed in the outer
peripheral portion on the side of the valve seat frame 70 where
working fluid flows out, and the height of the projection 74 is set
higher than the thickness of a valve body 80. The projection 74 is
crimped, with a fixing part 83 of the valve body 80 between (in the
figure, the shape indicated by the chain double-dashed line is
deformed to the shape indicated by numeral 74A), to a state in
which the valve body 80 is placed inside the projection 74, whereby
the valve body 80 is fixed. The projection 74 may be crimped fully
or partially.
[0198] Thus, the check valve 50 is put into a unit and is
press-fitted into an inner wall 114 of an opening of a pump chamber
body 101.
[0199] Therefore, in the second embodiment, the projection 74 of
the valve seat frame 70 is crimped fully or partially, whereby the
fixing part 83 of the valve body 80 is fixed to the valve seat
frame 70. As such, the valve body 80 can be fixed in a small space
reliably. The outer peripheral part of the fixing part 83 of the
valve body 80 is fixed, whereby the valve body 80 can be fixed
without deforming an opening-closing part 81 or a support part 84
(see FIG. 3) of the valve body 80.
[0200] The valve body 80 is simply placed in the projection 74 of
the valve seat frame 70, whereby the position in the plane
direction is regulated, so that the opening-closing part 81 can
hermetically seal a communication hole 61 for the working fluid of
the valve seat 60 reliably without using any special jig. FIG. 12
is a sectional view showing a check valve 50 of the third
embodiment of the invention. In the third embodiment, the fixing
structures of the valve bodies 80 to the valve seat frames 70 are
changed, and only this difference will be discussed. Functional
members identical with those of the first or second embodiments are
denoted by the same reference numerals in FIG. 12. In the figure, a
valve seat 60 is press-fitted into a valve seat frame 70. A tubular
projection 74 is formed in the outer peripheral portion on the side
of the valve seat frame 70 where the working fluid flows out. With
a valve body 80 placed inside the projection 74, a ring-like fixing
member 90 is press-fitted into the inside of the projection 74, and
a fixing part 83 of the valve body 80 is pressed and fixed between
a bottom 73 of the valve seat frame 70 and the fixing member
90.
[0201] The inner diameter of the fixing member 90 is set to a size
in a range that does not hinder the driving of an opening-closing
part 81 of the valve body 80. The side of a pump chamber 119 (see
FIG. 1) is chambered.
[0202] Thus, the check valve 50 is put into a unit and is
press-fitted into an inner wall 114 of an opening of the pump
chamber body 101 and is fixed.
[0203] Therefore, in the third embodiment, the valve body 80 is
fixed as the fixing part 83 provided on the periphery is sandwiched
between the valve seat frame 70 and the fixing member 90 so that
the valve body 80 can be fixed without producing an internal
stress. Thus, the valve body 80 can be fixed without deforming the
support part 84 or the opening-closing part 81.
[0204] FIGS. 13 and 14 show a check valve 50 and a valve body 80,
respectively, according to the fourth embodiment of the
invention.
[0205] FIG. 13 is a sectional view showing a check valve 50 of the
fourth embodiment, and FIG. 14 is a schematic perspective view
showing the valve body 80 of the fourth embodiment. The fourth
embodiment differs from the second or third embodiment only in the
fixing structure of the valve bodies 80 to a valve seat frames 70
and, therefore, only this difference will be discussed (see also
FIGS. 11 and 12).
[0206] In FIG. 13, a valve seat 60 is press-fitted into the valve
seat frame 70. A tubular projection 74 is formed in the outer
peripheral portion on the side of the valve seat frame 70 where
working fluid flows out, a tubular projection 85 is formed on the
outer periphery of a fixing part 83 of the valve bodies 80 (see
FIG. 14), and a ring-like fixing member 90 is press-fitted into the
inside of the projection 85, whereby the projection 85 of the valve
body is pressed and fixed between the projection 74 of the valve
seat frame 70 and the fixing member 90.
[0207] The inner diameter of the fixing member 90 is set to a size
in a range that does not hinder the driving of an opening-closing
part 81 of the valve body 80, and the side of a pump chamber 119
(see FIG. 1) is chambered.
[0208] The projection 85 of the valve body 80, the projection 74 of
the valve seat frame 70, and the fixing member 90 are set so as to
become almost the same height in a state in which they are
assembled.
[0209] Thus, the check valve 50 is put into a unit and is
press-fitted into an inner wall 114 of an opening of the pump
chamber body 101 and is fixed.
[0210] In FIG. 14, the valve body 80 will be discussed in detail.
The valve body 80 is formed like a vessel provided with the tubular
projection 85 in the outer peripheral portion, and is provided with
the opening-closing part 81 shaped roughly like a letter U as
described in the first embodiment (see FIG. 3).
[0211] The modified shape described in the first embodiment (see
FIG. 5, FIG. 6) can also be adopted as the shape of the
opening-closing part 81, a support part 84 of the valve body 80.
FIG. 15 is a sectional view showing a check valve 50 of the fifth
embodiment of the invention. The fifth embodiment differs from the
fourth embodiment (see FIG. 13) only in the fixing structure of the
valve body 80 and, therefore, only this difference will be
discussed. Functional members identical with those of the fourth
embodiment are denoted by the same reference numerals in FIG.
15.
[0212] In FIG. 15, the difference between the diameter of the outer
periphery of a valve seat 60 and the inner diameter of a valve seat
frame 70 is set a little smaller than the thickness of the valve
body 80. The valve body 80 is provided with a projection 85 in an
outer peripheral portion like the valve body 80 described in the
fourth embodiment (see FIGS. 13 and 14), but the projection 85 has
an outer diameter set a little larger than the inner diameter of
the valve seat frame 70, and has a height almost the same as the
thickness of the valve seat 60.
[0213] The check valve 50 is put into a unit as the valve seat 60
is first inserted into the projection 85 of the valve body 80, and
then is press-fitted into the valve seat frame 70. Alternatively,
the valve body 80 can also be inserted into the valve seat frame 70
before the valve seat 60 is press-fitted.
[0214] Thus, the check valve 50 is put into a unit and is
press-fitted into an inner wall 114 of an opening of a pump chamber
body 101 and is fixed.
[0215] Therefore, in each of the fourth and fifth embodiments, the
valve body 80 is provided with the projection 85 on the periphery,
whereby even if a thin plate of about 20 .mu.m, for example, is
used, it is reinforced as the projection 85 is provided in the
outer peripheral portion. As such, the valve body 80 is hard to
bend and is less deformed during handling.
[0216] Since the valve bodies can be manufactured by press working,
etc., the working step for providing the projection is not required
and the cost is not increased either.
[0217] In the fifth embodiment, the valve body 80 can be fixed
between the valve seat frame 70 and the valve seat and, thus, no
fixing member is required and the valve seat frame 70 need not be
provided with the projection 74. As such, the structure is simple
and the cost can also be reduced.
[0218] The modified shape described in the first embodiment (see
FIGS. 4 to 6) can also be adopted as the shape of the
opening-closing part 81, and the support part 84 of the valve body
80.
[0219] Next, a check valve 50 of a sixth embodiment of the
invention will be discussed with reference to FIGS. 16 to 21. FIGS.
16 and 17 show the check valve 50 of the sixth embodiment and a
modification thereof, and FIGS. 18 to 21 show valve bodies 80
adopted for the check valve 50.
[0220] In FIG. 16, a valve seat frame 70 is formed with a recess
part 75 so that a flat portion 66 of the top face of a valve seat
60 and the bottom face become roughly the same face on the side
where the working fluid flows out. The recess part 75 has a depth
to ensure a stroke in the cross-sectional direction required for
the valve body 80 to open and close a communication hole 61 (in the
figure, the range in which the valve body 80 moves from the
position indicated by the solid line to the position indicated by
the chain double-dashed line). A ring-like fixing member 90 is
fixedly secured to the lowest face of the valve seat frame 70 in
the figure. The inner diameter of a hole made in the fixing member
90 is set smaller than the outer dimension of the valve body 80 and
the diameter of the outer periphery is set smaller than the outer
dimension of the valve seat frame 70.
[0221] The valve body 80 is placed in the space formed by the
fixing member 90 and the recess part 75.
[0222] The valve body 80 moves in the cross-sectional direction for
opening or closing the communication hole 61 following motion of
the above-described diaphragm 150 (see FIG. 1).
[0223] FIG. 17 shows a modification of the retention structure of
the valve body 80. In FIG. 17, the valve seat frame 70 is provided
with an additional recess part 76 of a larger diameter than the
diameter of the recess part 75 below the recess part 75 in the
figure into which the valve body 80 is inserted, and the ring-like
fixing member 90 is press-fitted into the recess part 76. The valve
body 80 is placed in the space between the fixing member 90 and the
valve seat 60. The valve body 80 can move in the cross-sectional
direction in the figure as described above (also see FIG. 16).
[0224] FIGS. 18 to 21 show valve bodies 80 adopted for the sixth
embodiment. In FIG. 18, the valve body 80 is made up of a roughly
circular opening-closing part 81 at the center, a ring-like fixing
part 83 on the periphery, and three support parts 84 extending
radially for joining the opening-closing part 81 and the fixing
part 83. The size of the opening-closing part 81 is a size required
for hermetically sealing the communication hole 61 and needs to be
smaller to allow the working fluid to easily flow out when the
opening-closing part 81 is opened. Preferably, each of the support
parts 84 is set narrowly in a range in which the strength of the
valve body 80 can be ensured.
[0225] The opening-closing part 81, the support parts 84, and the
fixing part 83 of the valve body 80 are formed in the same
plane.
[0226] FIG. 19 shows another modification of the valve body 80. The
modification in FIG. 19 differs from the shape of the valve body
shown in FIG. 18 only in that support part 84 is formed as radiant
circular arcs, like a windmill.
[0227] FIG. 20 is a plan view of another modification of the valve
body 80 of the sixth embodiment, and FIG. 21 is a side view of the
valve body 80 visually recognized from the arrow direction in FIG.
20. In FIG. 20, a support part is implemented as a blade part 86
shaped like a propeller. The blade part 86 joins an opening-closing
part 81 and a fixing part 83. The shape of visually recognizing the
plane is a fan, and the cross-sectional shape is shown in FIG.
21.
[0228] In the valve body 80, the fixing part 83 is regulated at the
position in the cross-sectional direction by the recess part 75 of
the valve seat frame 70 and the fixing member 90, and the blade
part 86 is set in the range in which it does not come in contact
with the fixing member 90 or the valve seat 60.
[0229] In FIG. 21, the blade part 86 is bent like a bowl in cross
section and can be assumed to be a propeller having an astern plane
87 as the plane in the direction of the valve seat 60 and an ahead
plane 88 as an opposite side (see FIGS. 16 and 17). Therefore, when
pressure is imposed on the ahead plane 88, the valve body 80 is
pressed strongly against the valve seat 60, closing the
communication hole 61; when pressure is imposed on the astern plane
87, the valve body 80 is pressed in the direction away from the
valve seat 60, opening the communication hole 61, and working fluid
flows out smoothly along the moderate face of the astern plane
87.
[0230] In FIG. 21, the astern plane 87 of the blade part 86 is
projected above the top faces of the opening-closing part 81 and
the fixing part 83, but the shape can also be set so as not to
project from the opening-closing part 81 or the fixing part 83.
[0231] Therefore, in the sixth embodiment, the valve body 80 is not
fixed and can easily follow the stretch and contraction of the
diaphragm 150. When the valve body 80 is opened, the open area
where working fluid flows out becomes large, so that the outflow
amount can be increased.
[0232] The valve body 80 is regulated at the position in the plane
direction by the recess part 75 provided in the valve seat frame
70. The range of motion in the cross-sectional direction is also
regulated by the fixing member 90. In this manner, the diameter and
the depth of the recess part 75 are set appropriately, whereby the
move distance of the valve body 80 can be regulated properly.
[0233] If the valve body 80 is formed like a propeller (see FIGS.
20 and 21), when the working fluid flows out, the working fluid can
flow out from the space between the blades of the blade part 86 in
a small resistance state along the astern plane 87 of the moderate
curved face of the blade part 86 and when the communication hole is
closed by the diaphragm 150 as described above, working fluid
presses the ahead plane 88 shaped like a moderate bowl, whereby the
communication hole 61 can be closed efficiently, so that the
communication hole 61 can be opened and closed efficiently
following small motion of the diaphragm.
[0234] Although the valve body 80 according to the sixth embodiment
can be provided by molding a metal plate by pressing, etc., if
injection molding of a synthetic resin, etc., is performed, the
shape of the blade part 86 can be molded to a shape more similar to
a propeller and the efficiency of advance and backing can be
enhanced.
[0235] Next, a seventh embodiment of the invention will be
discussed with FIGS. 22 and 23. FIG. 22 is a sectional view of a
check valve 50 of the seventh embodiment, and FIG. 22 is a plan
view of a valve body 80 of the seventh embodiment. In FIG. 22,
three working fluid communication holes 61 are made in a valve seat
60. Each of the communication holes 61 are formed like a
cross-sectional shape similar to that in the embodiment described
above. The communication holes 61 are placed so as to form a
triangle in plan view. Although the shape of the valve body 80 is
described later (with reference to FIG. 23), the valve body 80 is
fixed with the positions of the opening-closing parts 81 matched
with the positions of the communication holes 61 in a projection 74
provided in a valve seat frame 70. As the fixing structure, any of
the fixing structures shown in the first to fifth embodiments
described above can also be adopted.
[0236] In FIG. 23, in the valve body 80, support parts 84 are
extended from the opening-closing parts 81 provided at the same
positions as the communication holes 61 of the valve seat 60, and
are made continuous to a fixing part 83. Each of the support parts
84 is set long in a range in which an elastic force required for
the opening and closing of the communication hole 61 can be
provided, and is also formed to have a shape that prevents torsion,
etc., from occurring at the time of bending.
[0237] The communication holes 61 are placed as a triangle in plan
view in FIG. 23, but may be placed in a line. Further, the number
of the communication holes is not limited.
[0238] The support part 84 may be extended radially from the center
of the valve body 80 and can be appropriately selected and set from
the layout of the communication holes 61, the size of the valve
body 80, and the elastic force of the support part 84. Therefore,
in the seventh embodiment, the valve seat 60 is provided with a
plurality of working fluid communication holes 61. Further, the
opening-closing parts 81 of the valve body 80 for opening and
closing the communication holes 61 are provided in a one-to-one
correspondence with the communication holes so that the check valve
50 can be formed without increasing the number of components. If
the amplitude of the diaphragm is about 10 .mu.m in a diaphragm
type pump, as described in the first embodiment, the operation
range of the opening-closing part 81 of the valve body 80 is about
20 .mu.m. Thus, to increase the flow amount of the working fluid, a
large number of communication holes 61 can be provided for
increasing the flow amount.
[0239] Although one opening-closing part 81 can also open and close
the plurality of communication holes 61, it is impossible to open
and close all the communication holes in a uniform manner because
of slight deformation or dimensional variations of the
opening-closing part 81. As the separate opening-closing parts 81
are provided in a one-to-one correspondence with the communication
holes, all the communication holes 61 can be opened and closed
reliably.
[0240] FIGS. 24 and 25 show a check valve 50 of the eighth
embodiment of the invention. FIG. 24 is a sectional view of the
check valve 50 of the eighth embodiment, and FIG. 25 is a plan view
that visually recognizes a valve body 80 from the arrow direction
in FIG. 24. In FIGS. 24 and 25, a valve seat 60 is press-fitted
into a through hole 71 made in a valve seat frame 70. A valve seat
shaft 91 provided with a projection shaft 92 having a smaller
diameter than the through hole 71 of the valve seat 60 is
press-fitted into the valve seat frame 70 from the inlet side of
working fluid.
[0241] The valve seat shaft 91 is formed as a ring-like fixing part
93, and a projection shaft 92 at the center is joined by three
support parts 94 (see FIG. 25). The height of the projection shaft
92 is set so as to become the same as a flat portion 66 of the top
face of the valve seat 60 when the valve seat shaft 91 is
press-fitted into the valve seat frame 70. As the valve seat 60 and
the valve seat shaft 91 are combined, the valve seat 60 is formed
with a ring-like communication hole 61 of working fluid. The valve
body 80 opens and closes the communication hole 61.
[0242] In FIG. 25, the valve body 80 is made up of a fixing part 83
on the outer periphery, an opening-closing part 81 at the center,
and support parts 84 for joining the opening-closing part and the
fixing part, and the opening-closing part 81 has an area covering
the ring-like communication hole 61 described above. Preferably,
the opening-closing part 81 or the contact area between the valve
seat shaft 91 and the opening-closing part 81 is smaller and in a
range in which the communication hole 61 can be hermetically sealed
reliably. Preferably, the center part of the opening-closing part
81 is punched for preventing extra contact, for example.
[0243] To fix the valve body 80 to the valve seat frame 70, any of
the structures in the embodiments described above can be
adopted.
[0244] Although not shown, the area of a communication hole 95 in
the valve seat shaft 91 is made larger than the area of the
communication hole 61 made in the valve seat 60 to allow a
sufficient amount of the working fluid to flow into the
communication hole 61. The check valve 50, in one unit, is
press-fitted into an inner wall 114 of an opening of a pump chamber
119.
[0245] Therefore, in the eighth embodiment, the communication hole
61 is opened like a ring, so that the flow amount of the working
fluid can be increased.
[0246] For a diaphragm type pump 10 using a piezoelectric element
as the actuator as described in the first embodiment (with
reference to FIG. 1), the amplitude of the diaphragm is small and
thus the fluid resistance can be reduced and the pump efficiency
can be enhanced by providing a plurality of small communication
holes, or by providing a ring-like communication hole rather than
by providing a large communication hole in the valve seat 60.
[0247] As the ring-like communication hole, the valve seat 60 can
be formed with a ring-like communication hole split like the valve
seat shaft 91. In this case, the valve seat shaft 91 becomes
unnecessary. However, when a hard material such as cemented carbide
or ceramics, etc., is selected for the valve seat 60, if the valve
seat shaft 91 shown in the eighth embodiment is used, the ring-like
communication hole 61 can be formed easily.
[0248] FIGS. 26 and 27 show valve bodies 80 according to the ninth
embodiment of the invention. The ninth embodiment provides
modifications of the joint relationship between the opening-closing
part 81 of the valve body 80 and the communication hole 61 shown in
the first to eighth embodiments. In FIG. 26, an opening-closing
part 81 of a valve body 80 is formed with a projection 89 shaped
like a dome. The projection 89 comes in contact with an outlet 63
of a communication hole 61 of a valve seat 60 for hermetically
sealing the outlet 63.
[0249] As shown in FIG. 27, the opening-closing part 81 of the
valve body 80 can be provided with a projection 89 shaped roughly
like a cone. The dome type or cone type can be selected based on
conditions such as the size of the communication hole 61, obtained
pressing force, etc.
[0250] Therefore, to adopt the valve body shape as in the ninth
embodiment, in the valve body 80, if the opening-closing part 81 is
shaped like a dome or a cone, contact with the outlet 63 becomes
linear contact, contact pressure is increased, and leakage of the
working fluid can be prevented. When the opening-closing part 81 is
opened, the distance between the valve seat 60 and a support part
84 continuous to the projection 89 of the opening-closing part
becomes large as compared with the case where contact is made on a
plane, and working fluid can also flow out easily.
[0251] In the first to ninth embodiments, the best modes of the
fixing structure of the valve seat frame 70 and the valve body 80,
the structure of the valve body 80, the structure of the valve seat
60, etc., are shown, but it should be understood that an optimum
combination thereof can be selected as desired depending on the
size of the pump 10, the target performance, etc.
[0252] In the seventh embodiment, the valve body 80 includes the
plurality of opening-closing parts 81 in a one-to-one
correspondence with the plurality of communication holes 61 of the
valve seat 60, but can also include a plurality of valve bodies in
a one-to-one correspondence with the communication holes 61.
[0253] Further, in the first to ninth embodiments, the valve seat
60, the valve seat frame 70, and the valve body 80 are put into one
unit, but the valve seat 60 and the valve body 80 can be directly
fixed to the valve seat 60 so that they are put into one unit
depending on selection of the size and material of the valve body
80.
[0254] Subsequently, a tenth embodiment of the invention will be
discussed based on the accompanying drawings. The tenth embodiment
is characterized in that a ball is adopted while the valve body of
the check valve shown in each of the first to ninth embodiments is
formed of a plate member, and is the same as the embodiments
described above in the basic configuration, the drive principle,
etc., of the pump 10 and therefore the basic configuration, the
drive principle, etc., will not be discussed again. Functional
members and components of the check valve identical with those
previously described in the above embodiments are denoted by the
same reference numerals.
[0255] FIG. 28 shows the cross-sectional shape of a check valve 50
according to the tenth embodiment. In FIG. 28, the check valve 50
is made up of a valve seat frame 70, a valve seat 60, a ball 130,
and a ball support member 160.
[0256] The valve seat 60 is a ring-like member having a
communication hole 61 for working fluid made at the center, and an
inlet 62 and an outlet 63 for the working fluid of the
communication hole 61 are rounded smoothly. The inlet side is
rounded to decrease the inflow resistance of the working fluid and
the outlet side is rounded to decrease a vortex occurring when the
working fluid flows out.
[0257] The inlet 62 is provided with a slope 69 shaped roughly like
a circular arc, and this portion is formed like a funnel for
introducing the working fluid smoothly into the communication hole
61.
[0258] The outer peripheral surface of the valve seat 60 on the
outflow side thereof is chambered for facilitating press-fitting
into the valve seat frame 70.
[0259] Cemented carbide or ceramics (Al.sub.2O.sub.3, etc.,) is
adopted as the material of the valve seat 60 as in the first
embodiment. The valve seat 60 is press-fitted into a hole 71 of the
valve seat frame 70.
[0260] The valve seat frame 70 is formed like a ring having the
hole 71 made at the center into which the valve seat 60 is
press-fitted, and the working fluid inflow side of the hole 71 is
formed as a shape rounded smoothly from roughly the same position
as the height of a top face 65 in the figure, of the valve seat 60
and continuous to a slope 72 opened wider than the hole 71 in the
upper part.
[0261] Further, a hole 77 that is pierced from the inside of the
valve seat frame 70 to the outside is made at roughly the same
position as the ball 130 in the cross-sectional direction of a
tubular part of the valve seat frame 70. The hole 77 is set to a
size required for inspecting the state of the ball 130 in the check
valve 50.
[0262] On the opposite side to the slope 72, a tubular projection
74 is formed toward the inside in the inner peripheral part of the
hole 71. The ball support member 160 is placed on the projection
74.
[0263] Thus, the valve seat frame 70, the valve seat 60, the ball
130, and the ball support member 160 are put into a unit and are
press-fitted into an inner wall 114 of a pump chamber body 101.
[0264] The ball support member 160, which is described later (with
reference to FIG. 28), is formed with three claw parts 161 at the
center. The ball 130 is included in the claw parts 161. The ball
130 is spherical, has a gap in which it can move between the outlet
63 of the valve seat 60 and the claw parts 161, hermetically seals
the outlet 63 for blocking outflow of working fluid (indicated by
the chain double-dashed line in the figure), and opens the outlet
63 for allowing the working fluid to flow (indicated by the solid
line).
[0265] FIG. 29 is a plan view of the ball support member 160 of the
tenth embodiment. In FIG. 29, the ball support member 160 is formed
like a ring whose outer periphery is a little smaller than the hole
71 of the valve seat 70 described above, and is larger than the
inner diameter of the projection 74 (see also FIG. 28). A ball
support part 162 shaped roughly like a ring is provided at the
center of the ball support member 160, a communication hole 163 of
working fluid is made in the center of the ball support part 162,
and the ball support part 162 and an outer periphery support part
164 on the outer periphery are joined by three support parts 165.
From the ball support part 162, the claw parts 161 are projected
radially each between the contiguous support parts 165 and are bent
up upward in the cross section (see FIG. 28). The claw parts 161
are bent up to such a shape supporting the hemisphere of the ball
130 and the ball 130 does not largely move in the plane
direction.
[0266] Preferably, the claw part 161 has dimensions to the range
below the center of the ball 130 as shown in FIG. 28 to decrease
the outflow resistance of the working fluid.
[0267] Therefore, in FIGS. 28 and 29, when the communication hole
61 is hermetically sealed, the ball 130 is pushed up by the working
fluid made to flow from the communication hole 163 of the ball
support member 160 and the opening between the support parts 165
and presses the outlet 63 of the valve seat 60 (indicated by the
chain double-dashed line in FIG. 28). The ball support member 160
is also pushed up by the working fluid and presses the ball 130
against the outlet 63. When the communication hole 61 is opened,
the ball support member 160 moves to a position where movement is
regulated by the projection 74 of the valve seat frame 70 and the
ball 130 also moves to the positions of the claw parts 161, which
opens the communication hole 61 that allows the working fluid to
flow out from the opening between the support parts 165 and the
communication hole 163.
[0268] Next, a modification of the ball support member 160 of the
tenth embodiment will be discussed with FIG. 30 (also see FIGS. 28
and 29).
[0269] FIG. 30 shows, in cross section, the ball support member
160. In FIG. 30, the ball support member 160 is formed with a
tubular side guide part 166 that is projected toward the valve seat
60 on the periphery of the outer periphery support part 164.
[0270] The diameter of the outer periphery of the side guide part
166 is set a little smaller than the diameter of the inner
periphery of the hole 71 of the valve seat frame 70 and can move in
the direction of the valve seat 60 along the wall of the hole 71.
The shape of the claw parts 161, etc., other than the side guide
part 166 is formed as the same shape as the ball support member 160
shown in FIG. 29.
[0271] Although the material of the ball support member 160 is not
limited, stainless steel can be adopted considering the structural
strength and corrosion resistance and an aluminum alloy, a
synthetic resin, etc., can be adopted taking weight reduction into
consideration. To adopt an aluminum alloy, preferably the surface
is subjected to oxidation resistance treatment such as anodizing,
etc. To adopt a synthetic resin, etc., injection molding can be
conducted and thus the positional relationship between the claw
parts 161 and the support parts 165 can be selected as desired.
FIG. 31 shows the cross section of the valve seat 60 of the tenth
embodiment. In FIG. 31, the valve seat 60 has the working fluid
communication hole 61 made at the center, and as described above,
the inlet 62 and the outlet 63 of the communication hole 61 are
rounded smoothly and the inlet 62 is provided with the slope 69
continuous as a circular arc like a funnel so that working fluid is
easily introduced into the communication hole 61. The outlet 63 is
formed with a dent 63A having a circular arc of a larger diameter
than the diameter of the ball 130 and a smoothly continuous shape
is formed from the communication hole 61 to the dent 63A.
[0272] In FIG. 31, when the ball 130 moves from a position where
the communication hole 61 is hermetically closed (130A) to a
position 130B where the communication hole 61 is opened, the
average distance from the dent 63A of the valve seat 60 to the ball
130 becomes large if the movement distance of the ball 130 in the
vertical direction is the same, as compared to a case where the
dent 63A does not exist (not shown). This means that as the flow
cross-sectional area of the working fluid increases, the fluid
resistance decreases.
[0273] Subsequently, the ball 130 according to the tenth embodiment
will be discussed with FIG. 32. FIG. 32 is a sectional view of the
ball 130 of the tenth embodiment for opening and closing the valve
seat 60. In FIG. 32, the ball 130 is spherical and is made up of an
outer shell 131 and a hollow part 132. A metal material such as an
iron-based alloy, a stainless alloy, a copper-based alloy, or an
aluminum alloy or a non-metallic material such as glass, ceramics,
or a synthetic resin can be adopted for the ball 130. The center
part is hollow to lessen the average value of a density of the ball
130. Accordingly, in the working fluid, the weight per unit volume
of the ball 130 is roughly the same as the weight per unit volume
of the working fluid pushed away by the ball 130.
[0274] Assuming that the working fluid is water having a specific
gravity of 1 and the material of the ball 130 is an iron-based
alloy having a specific gravity of 7.9, the thickness of the outer
shell 131 becomes about 4.5% of the radius of the ball 130. The
thickness of the outer shell 131 is calculated by the specific
gravities of the working fluid and the ball material. Therefore, if
the material of the ball 130 is glass having a specific gravity of
4, the thickness of the outer shell 131 may be made about 8.9% of
the radius of the ball.
[0275] If a synthetic resin, etc., having a specific gravity of 1
is adopted, the ball 130 does not require the hollow part 132.
Further, if the working fluid has a large specific gravity or the
drive capability (pressure) of the pump described above is
sufficiently large, the hollow part is not required either.
[0276] Therefore, in the tenth embodiment, the check valve 50 is
made up of the four parts of the valve seat 60, the valve seat
frame 70, the ball 130, and the ball support member 160. Thus, the
number of components is small, and each component has a simple
shape so that the check valve 50 can be manufactured easily, shape
management is also easy to conduct, and the check valve 50 can be
manufactured at low cost. Since the check valve 50 is put into a
unit, performance management can be conducted in a single unit as
the check valve 50 and when the check valve 50 is built in the pump
10, stable performance of the check valve 50 can be provided
without again adjusting or inspecting the check valve 50.
Consequently, a pump having stable performance can be provided. The
check valve 50 can be built in the pump 10 without touching the
ball 130 or the communication hole 61 of the valve seat 60 so that
predetermined performance can be provided without causing damage to
or deforming the check valve 50 during assembly.
[0277] Since the valve seat 60 is opened and closed by the ball
130, when the valve seat 60 is open, working fluid flows on the
surface of the ball and thus the flow resistance is small. When the
valve seat 60 is hermetically sealed, the valve seat 60 and the
ball 130 come in line contact with each other, the contract
pressure increases, and the valve seat 60 can be hermetically
sealed reliably.
[0278] Since the ball support member 160 supporting the ball 130
has the shape as shown in FIGS. 29 and 30, it can be easily formed
of a metal plate material by working means of pressing, etc., for
example. The center of the ball 130 from the communication hole 163
of the ball support member 160 and, further, the peripheral part
from the opening between the support parts 165 are pushed up by
working fluid and the ball 130 presses the valve seat 60 for
hermetically sealing the communication hole 61. Thus, the ball 130
easily moves as the pressure of the working fluid changes, and the
communication hole 61 of the valve seat 60 can be hermetically
sealed reliably.
[0279] Further, the ball 130 is supported by the three projected
claw parts 161 provided in the ball support member 160, and the
claw parts 161 support the ball 130 in the range smaller than the
diameter of the ball 130 so that the claw parts can support the
ball 130 in a state in which the flow of the working fluid is less
hindered and can support the ball 130 more reliably.
[0280] The ball 130 and the ball support member 160, and the ball
support member 160 and the valve seat frame 70, are supported, but
not fixed. Therefore, as only the ball 130 moves, the communication
hole 61 of the valve seat 60 can be opened and closed; the ball 130
can be pushed up by the ball support member 160 for hermetically
sealing the communication hole 61; and the ball 130 and the ball
support member 160 can move together for opening the communication
hole 61. Because of the structure wherein not only the ball 130,
but also the ball support member 160 can move, the ball support
member 160 can receive positive pressure of the pump chamber and
press the ball 130, for example, so that the hermetic sealing force
of the communication hole 61 can be enhanced.
[0281] In the ball support member 160 shown in FIG. 30, the tubular
side guide part 166 is provided on the periphery of the outer
periphery support part 164, so that the ball support member 160
moves along the inner wall of the hole 71 and thus is not inclined
and can move smoothly for opening and closing the communication
hole 61 reliably as compared with the case where the side guide
part 166 does not exist. Although the side guide part 166 is
provided, it is not necessary to increase the space of the check
valve 50.
[0282] Since the average value of the density of the ball 130 and
the density of working fluid are made roughly the same, the ball
130 is in a floating state or a state close to the floating state
in the working fluid, for example, if driving of the pump 10 is
stopped. Thus, if the pump 10 is driven, the ball 130 moves due to
a slight pressure change of the working fluid, so that if an
actuator 301 of the pump 10 is driven at a high frequency like a
piezoelectric element, the ball moves in synchronization with the
driving and can open and close the valve seat 60.
[0283] In the tenth embodiment, the ball 130 is hollow and thus the
average value of the density can be decreased and the thickness of
the outer shell 131 of the ball 130 is adjusted according to the
material of the ball 130 and the material of the working fluid,
whereby the weight per unit volume of the ball 130 can be set to
roughly the same as the weight per unit volume of the working fluid
pushed away by the ball 130 as described above. Thus, the ball can
moves due to slight pressure change of the working fluid as
described above, so that as with the pump 10 of the embodiment, the
ball easily moves in synchronization with driving the actuator and
can open and close the valve seat 60 at high speed and
reliably.
[0284] Further, the communication hole 61 of the valve seat 60 has
the inlet 62 and the outlet 63 where the working fluid flows are
formed smoothly and continuously as roughly circular arcs c, and
the outlet 63 is formed on the outside of the opening with the dent
63A having a circular arc of a larger diameter than the diameter of
the ball 130 so that the flow resistance when the working fluid
flows through the valve seat 60 can be decreased. Particularly, the
outlet 63 is opened and closed by the ball 130 and thus when the
outlet 63 is formed on the outside of the opening with the dent 63A
having a circular arc larger than the diameter of the ball, even
when the ball 130 is brought slightly away from the valve seat 60,
the cross-sectional area of the opening where the working fluid
flows out can be provided widely, so that the outflow amount of the
working fluid can be increased. This also provides the effect of
promoting a bringing of the ball 130 away from the valve seat
60.
[0285] The ball 130 moves to the outlet 63 along the dent 63A and
hermetically seals the communication hole 61. Thus, if the ball 130
moves with the plane direction position of the ball 130 varying
slightly, the ball is guided into the surface of the dent 63A and
can hermetically seal the communication hole 61 more reliably.
[0286] Subsequently, an eleventh embodiment according to the
invention will be discussed based on the accompanying drawing. The
eleventh embodiment is characterized in that it differs from the
tenth embodiment in the form of a ball. Functional parts identical
with those previously described in the tenth embodiment are denoted
by the same reference numerals in the description to follow.
[0287] FIG. 33 shows a cross section of a ball 130 according to a
eleventh embodiment of the invention. The ball 130 shows another
embodiment of the ball 130 placed in the check valve 50 described
(with reference to FIG. 28) in the tenth embodiment. In FIG. 33,
the ball 130 is a sphere provided with a hollow part 132, and an
outer shell 131 is formed on the surface with a coating 133. As the
coating, a hard anodic oxide coating of cemented carbide, a metal
such as nickel or chromium, and ceramics, etc., can be adopted. As
means for coating, a wet plating such as an electroplated coating
or a chemical plating or a dry plating such as vacuum evaporation,
sputtering, or ion plating can be adopted. The means chosen for
plating can be selected in conformance with the material of the
ball 130.
[0288] A rubber-based soft material can also be adopted as the
coating.
[0289] Preferably, the average value of the density of the ball 130
and the mass of working fluid are made roughly the same, as
described above and therefore the thickness of the coating 133 is
set conforming to the material of the ball 130 and the thickness of
the outer shell 131; preferably the thickness of the coating is set
to 5 .mu.m or more to ensure the structural strength.
[0290] The coating 133 can be formed of one layer or can be formed
of multiple layers using a plurality of different materials in
combination. For example, a soft coating can also be put on the
upper layer of a hard anodic oxide coating.
[0291] Therefore, in the eleventh embodiment, the ball 130 for
opening and closing a communication hole 61 is formed on the outer
shell surface with the coating 133. Thus, even if the material of
the ball 130 is limited from standpoint of ease of manufacturing,
if a hard anodic oxide coating is selected, the hardness of the
surface is high and thus the ball is less worn or is less damaged
by the shock of opening and closing the communication hole 61 even
if the ball is used for a long term.
[0292] If the ball 130 is made hollow as described above, the
coating can prevent the ball 130 from becoming deformed.
[0293] Further, if a rubber-based soft coating is selected, the
sealing property of the valve seat 50 can be enhanced.
[0294] Subsequently, a twelfth embodiment of the invention will be
discussed with FIGS. 34 and 35. The twelfth embodiment differs from
the tenth embodiment (see FIG. 28) in the ball support structure of
check valve 50 and therefore this difference will be discussed in
detail. Functional members and parts identical with those in the
tenth embodiment are denoted by the same reference numerals in the
description to follow.
[0295] FIG. 34 is a sectional view showing a check valve 50
according to the twelfth embodiment. In FIG. 34, a valve seat 60 is
press-fitted into a hole 71 of a valve seat frame 70, a ball
support member 160 is placed in a projection 74 provided on the
valve seat frame 70, and a ball 130 is provided between the valve
seat 60 and the ball support member 160. That is, they are put into
a unit. The check valve 50 is press-fitted into an inner wall 114
of an opening of a pump chamber body 101.
[0296] FIG. 35 is a plan view of the ball support member 160
according to the twelfth embodiment. In FIG. 35, the ball support
member 160 is made up of an outer periphery support part 164, a
ball support part 162 for supporting the ball 130, and three
support parts 165 for joining the outer periphery support part 164
and the ball support part 162. A communication hole 163 where the
working fluid flows is made in the center of the ball support part
162. The ball 130 moves between the ball support part 162 and the
valve seat 60 and opens and closes a working fluid communication
hole 61 of the valve seat 60.
[0297] In FIG. 34, to open the valve seat 60, the ball 130 is
regulated at a position in the plane direction with a part of the
ball inserted into the communication hole 163 of the ball support
member 160. The ball support member 160 exists at the position
abutting the projection 74 of the valve seat frame 70. This state
is indicated by the solid line in the figure. When the ball 130
hermetically seals the communication hole 61, the ball 130 presses
an outlet 63 of the valve seat 60. The ball 130 and the ball
support member 160 at the time are indicated by the chain
double-dashed line in the figure.
[0298] The distance between the ball support member 160 and the
valve seat 60 is set to a distance in engagement with the
communication hole 163 regardless of the state in which the ball
130 opens or closes the valve seat 60, so that the ball 130 does
not deviate from between the communication hole 163 and the outlet
63.
[0299] Therefore, the check valve 50 in the twelfth embodiment does
not include the claw parts 161 of the ball support member 160
(described with reference to FIGS. 29 and 30) in the tenth
embodiment and thus can be formed easily of a metal plate material
by working means of pressing, etc. Since no claw parts 161 are
included, the communication hole 163 made in the ball support
member 160 can be made large and the area of the ball 130 pushed up
by working fluid becomes wide, so that the ball 130 easily moves
and the communication hole 61 of the valve seat can be hermetically
sealed reliably.
[0300] When the ball 130 is brought away from the valve seat 60 and
the valve seat 60 is opened, the ball 130 is regulated at the
position and is supported in a state in which it is inserted into
the communication hole 163, so that the ball can be supported at
the appropriate position with a small space and moreover in a
simple shape. FIGS. 36 and 37 are a sectional view of a check valve
50 of the thirteenth embodiment and a plan view of a ball support
member 160 respectively. The thirteenth embodiment differs from the
twelfth embodiment only in that the ball support member 160 is
provided with an elastic part 167 for pressing a ball 130 and
therefore only this difference will be discussed. In FIGS. 36 and
37, the ball support member 160 is formed with the elastic part 167
projecting like a tongue in a communication hole 163 at the center.
Other shapes are the same as those of the ball support member 160
in the twelfth embodiment (with reference to FIG. 35).
[0301] In FIG. 36, the ball 130 is pressed against an outlet 63 of
the valve seat 60 by the elastic force of the elastic part 167 of
the ball support member 160 and hermetically seals the valve seat
60 (indicated by the chain double-dashed line in the figure). At
the time, the ball pressing force of the elastic part 167 may be a
force to such an extent that the ball 130 comes in contact with the
outlet 63, and the most of the valve seat pressing force of the
ball 130 is the pressing force of working fluid. At the time, it is
considered that the ball support member 160 is also pushed up by
the working fluid. That is, the ball support member 160 moves to
the position where the ball 130 and a corner of the inner wall of
the communication hole 163 come in contact with each other. At this
time, the elastic part 167 is bent in the outside direction of the
check valve 50.
[0302] The ball 130 presses down the elastic part 167 and is
brought away from the valve seat 60 for opening the outlet 63. When
the outlet 63 is opened, the elastic force of the elastic part 167
is set to a size to such an extent that the ball can be opened by
negative pressure in the pump chamber 119.
[0303] Therefore, according to the thirteenth embodiment, the ball
130 opens and closes the outlet 63 of the valve seat 60, and the
ball support member 160 is provided with the elastic part 167.
Thus, the ball 130 can be pressed against the outlet 63 by the
pressing force provided by adding the elastic force and the working
fluid pressure for hermetically sealing the outlet 63 reliably. If
the ball 130 is brought into contact with the outlet 63 of the
valve seat 60 at all times by the elastic part 167, when a pump 10
is stopped, working fluid can be prevented from flowing out.
[0304] FIGS. 38 and 39 are a plan view and a sectional view showing
a ball support member 180 of the fourteenth embodiment according to
the invention. The fourteenth embodiment is characterized in that
the ball support member is formed of a wire while the ball support
member 160 in each of the tenth to thirteenth embodiments is a
plate-like member. In FIGS. 38 and 39, the ball support member 180
is formed of a wire that is circular or rectangular in cross
section, has a ball support part 182 wound at the center, and is
formed at both ends with support parts 185 extended and wound
symmetrically with respect to a point with the ball support part
182 as the center. The support parts 185 and the top face of the
ball support part 182 are at the same height. The center formed by
ball support part 182 is a communication hole 183 of working fluid
and has roughly the same size as the communication hole 163 of the
ball support member 160 described (with reference to FIG. 35) in
the twelfth embodiment.
[0305] The ball support member 180 thus formed is placed in a valve
seat frame 70 like the ball support member 160 shown (with
reference to FIG. 34) in the twelfth embodiment, although not shown
here. This means that the ball support member is placed with the
support parts 185 at both ends engaged in and supported on a
projection 74 of the valve seat frame 70.
[0306] A material with large structural strength such as stainless
steel or a piano wire is adopted for the ball support member 180 of
the embodiment. If SPRON material (SPRON is a trademark of Seiko
Instrument Kabushikikaisha. The main component is an alloy of Co,
Ni, and Cr) used with a hair spring of a clock, etc., generally
called a constant modulus material is adopted, the ball support
member 180 using a finer wire can be provided.
[0307] Therefore, according to the fourteenth embodiment, similar
advantages to those of the twelfth embodiment described above can
be provided and in addition, since the ball support member 180 is
formed of a fine wire, the fluid resistance of working fluid can be
substantially decreased particularly when the working fluid flows
out from a valve seat 60. If the ball support member 180 is formed
of a wire circular in cross section, the fluid resistance can be
still more decreased.
[0308] The ball support member 180 can be easily manufactured by
means of wire forming, etc., and large facilities are not required.
Thus, the ball support member 180 is also effective for cost
reduction.
[0309] FIG. 40 is a sectional view showing a check valve of the
fifteenth embodiment. The fifteenth embodiment is characterized in
that a ball support member 160 is fixedly secured to a valve seat
frame 70. In FIG. 40, the ball support member 160 has the same
shape as the ball support member 160 (shown in FIG. 29) in the
tenth embodiment, and the outer diameter of an outer periphery
support part 164 is formed larger than the inner diameter of a
valve seat placement hole 71 of a valve seat frame 70.
[0310] A ring-like projection 74 for regulating the position of the
ball support member 160 is provided at the working fluid outflow
end of the valve seat frame 70, the ball support member 160 is
placed inside the projection 74, and the valve seat frame 70 and
the ball support member 160 are fixedly secured by securing means
of welding, adhesion, etc.
[0311] Therefore, according to the fifteenth embodiment, the ball
130 opens and closes a communication hole 61 solely, but the ball
support member 160 is fixedly secured to the valve seat frame 70,
and the ball 130 is regulated at a position in the plane direction
by claw parts 161 of the ball support member 160, so that the
position of the ball relative to the communication hole of the
valve seat can be regulated more precisely.
[0312] Because of the structure wherein only the ball 130 moves, a
check valve of a simple structure can be provided as compared to
the structure wherein the ball support member 160 moves.
[0313] The invention is not limited to the embodiments described
above and modifications, improvements, etc., in the range in which
the object of the invention can be accomplished are contained in
the invention.
[0314] For example, in the tenth to thirteenth embodiments
described above, the check valve 50 as a unit of the valve seat 60,
the valve seat frame 70, the ball 130, and the ball support member
160 is built in the pump chamber body 101, but the valve seat 60,
the ball 130, and the ball support member 160 can be directly built
in without using the valve seat frame 70.
[0315] FIG. 41 is a sectional view of a check valve 50 using no
valve seat frame 70. A pump chamber body 101 is formed with a hole
communicating with a pump chamber 119 from an opening 113 (also see
FIG. 1), a projection 102 shaped like a ring is formed on the
inside of an inner wall 114 of the hole, and the outer periphery
support part 164 of the ball support member 160 previously
described with FIG. 29 or 30 is supported on the projection 102. A
ball 130 is placed inside claw parts 161 of the ball support member
160, and a valve seat 60 is press-fitted into an inner wall 114 of
the pump chamber 101 to form the check valve 50.
[0316] In such a structure, the advantage of putting the check
value 50 into one unit as in the embodiment described above cannot
be provided, but a similar advantage to that of the embodiment
described above can be provided for opening and closing the valve
seat 60. The structure can also be made simpler.
[0317] The ball support member 160 shown (with reference to FIG.
35) in the twelfth embodiment or the ball support member 160 shown
(with reference to FIG. 37) in the thirteenth embodiment can be
adopted for the structure of fixedly securing the ball support
member 160 and the valve seat frame 70 (with reference to FIG. 40)
as in the fifteenth embodiment.
[0318] Further, in the tenth to thirteenth embodiments described
above, the ball 130 and the ball support member 160 are separated,
but the ball 130 and the ball support member 160 shown in the
twelfth embodiment can also be fixed in one piece by means of
adhesion, etc., so that the ball 130 and the ball support member
160 move together for opening and closing the valve seat 60, for
example.
[0319] In the eleventh embodiment described above, the ball 130 is
a hollow sphere, but a porous material such as a styrol-based
porous synthetic resin or porous ceramics can also be adopted. To
adopt a porous material, a watertight coating is formed on the
surface.
[0320] To use such a porous material, the weight of the ball 130
can be reduced and the ball 130 need not necessarily be made
hollow.
* * * * *