U.S. patent application number 11/526366 was filed with the patent office on 2007-03-29 for diaphragm pump.
This patent application is currently assigned to ALPS ELECTRIC CO., LTD.. Invention is credited to Jiro Nakajima, Satoshi Yamada.
Application Number | 20070071615 11/526366 |
Document ID | / |
Family ID | 37894214 |
Filed Date | 2007-03-29 |
United States Patent
Application |
20070071615 |
Kind Code |
A1 |
Nakajima; Jiro ; et
al. |
March 29, 2007 |
Diaphragm pump
Abstract
A diaphragm pump is provided. The diaphragm includes an upper
housing, a diaphragm, and a lower housing. Recessed parts are
formed in the surfaces of the upper and lower housings that face
the diaphragm to define an upper pump chamber and a lower pump
chamber above and below the diaphragm. A suction port and a
discharge port are formed in the lower housing to communicate with
the lower pump chamber. Branch channels are formed in the lower
housing and the upper housing to communicate the suction port and
the discharge port with the upper pump chamber. Suction-side check
valves are respectively provided between the suction port and the
upper pump chamber and between the suction port and the lower pump
chamber. Discharge-side check valves are provided between the
discharge port and the upper pump chamber and between the discharge
port and the lower pump chamber.
Inventors: |
Nakajima; Jiro;
(Niigata-ken, JP) ; Yamada; Satoshi; (Niigata-ken,
JP) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
ALPS ELECTRIC CO., LTD.
|
Family ID: |
37894214 |
Appl. No.: |
11/526366 |
Filed: |
September 25, 2006 |
Current U.S.
Class: |
417/397 |
Current CPC
Class: |
F04B 43/04 20130101 |
Class at
Publication: |
417/397 |
International
Class: |
F04B 35/00 20060101
F04B035/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2005 |
JP |
2005-280548 |
May 16, 2006 |
JP |
2006-136693 |
Claims
1. A diaphragm pump comprising: an upper housing, diaphragm, and
lower housing; recessed parts thatare respectively formed in the
surfaces of the upper and lower housings opposing the diaphragm to
define an upper pump chamber and a lower pump chamber above and
below the diaphragm; a suction port and a discharge port that are
formed in the lower housing to communicate with the lower pump
chamber; branch channels that are formed in the lower housing and
the upper housing to communicate the suction port and the discharge
port with the upper pump chamber; suction-side check valves that
are provided between the suction port and the upper pump chamber
and between the suction port and the lower pump chamber; and
discharge-side check valves that are provided between the discharge
port and the upper pump chamber, and between the discharge port and
the lower pump chamber, wherein the branch channels include at
least one hole, a protruding cylindrical part fitted into the hole,
and a sealing ring disposed in an annular gap formed between the
hole and the protruding cylindrical part such that a compressive
force is generated in the radial direction of the sealing ring.
2. The diaphragm pump according to claim 1, wherein the upper
housing includes a pump chamber plate that is stacked on the
diaphragm and has the recessed part, and a blind plate stacked on
the pump chamber plate.
3. The diaphragm pump according to claim 2, wherein a pair of
inter-plate suction flow channels and an inter-plate discharge flow
channel that communicate the suction port and the discharge port
with the upper pump chamber and that constitute parts of the branch
channels are formed between the pump chamber plate and the blind
plate.
4. The diaphragm pump according to claim 3, wherein the inter-plate
suction flow channel and the inter-plate discharge flow channel
includes a pair of protruding parts formed in any one of the pump
chamber plate and the blind plate.
5. The diaphragm pump according to claim 4, wherein a pair of
recessed groove parts that are formed in the another pump chamber
plate and the blind plate to allow the pair of protruding parts to
fit thereinto.
6. The diaphragm pump according to claim 5, wherein a pair of
sealing rings which are disposed in a pair of closed curve gaps
between the pair of protruding parts and the pair of recessed
groove parts such that a compressive force are generated
radially.
7. The diaphragm pump according to claim 1, wherein the upper
housing is composed of an upper plate stacked on the diaphragm and
a pair of lid plates.
8. The diaphragm pump according to claim 7, wherein the upper plate
is formed with recessed parts that are opened to the front and back
of the upper plate to form the upper pump chamber.
9. The diaphragm pump according to claim 8, wherein a pair of open
suction flow channel grooves and an open discharge flow channel
groove that constitute parts of the branch channels that
communicate the suction port and the discharge port with the upper
pump chamber, any one of the upper plate and the pair of lid plates
is formed with protruding parts corresponding to the open suction
flow channel groove and the open discharge flow channel groove.
10. The diaphragm pump according to claim 9, wherein the other one
of the upper plates and the pair of lid plates is formed with
recessed groove parts to allow the pair of protruding parts to fit
thereinto.
11. The diaphragm pump according to claim 9, wherein a pair of
sealing rings are interposed between the protruding parts and the
recessed groove parts such that a compressive force is generated
radially.
12. The diaphragm pump according to claim 2, wherein the protruding
parts, the recessed groove parts, and the sealing rings are
elliptical.
13. The diaphragm pump according to claim 3, wherein the protruding
parts, the recessed groove parts, and the sealing rings are
elliptical.
14. The diaphragm pump according to claim 1, wherein a compressive
force in the stacked direction of the upper housing, the diaphragm,
and the lower housing is not applied to any of the sealing
rings.
15. The diaphragm pump according to claim 1, wherein the at least
one hole is formed in the upper housing.
16. The diaphragm pump according to claim 1, wherein the at least
one hole is formed in the lower housing.
Description
[0001] This application claims the benefit of Japanese Patent
Application No. 2005-280548 filed on Sep. 27, 2005 and Japanese
Patent Application NO. 2006-136693 filed on May 16, 2006.
BACKGROUND
[0002] 1. Field
[0003] The present embodiments relate to a diaphragm pump.
[0004] 2. Related Art
[0005] A diaphragm pump, as disclosed in, for example, Japanese
Unexamined Patent Application Publication No. 11-182413, is
configured such that a pump chamber (variable volume chamber) is
formed by a diaphragm. A pair of flow channels connected with the
pump chamber is provided with a pair of check valves, which are
different in the direction of flow (a suction-side check valve,
which allows the flow of fluid to the pump chamber, and a
discharge-side check valve, which allows the flow of fluid from the
pump chamber). When the diaphragm is vibrated, since the volume of
the pump chamber changes, and the operation of opening the
suction-side check valve during the stroke in which the volume
increases, and the operation of opening the discharge-side check
valve during the stroke in which the volume reduces, are repeated,
a pumping action is obtained. The diaphragm is made of elastic
(vibrational) materials, for example, rubber and piezoelectric
vibrator.
[0006] In this diaphragm pump, as described above, since the
operation of opening the suction-side check valve during the stroke
in which the volume of the pump chamber increases, and the
operation of opening the discharge-side check valve during the
stroke in which the volume reduces, are repeated, pulsation in the
discharge port is inevitable.
[0007] A diaphragm pump with half the cycle of the pulsation has
been disclosed (Japanese Patent Application No. 2004-154991).
According to this diaphragm pump, an upper pump chamber and a lower
pump chamber (a pair of pump chambers) are respectively formed
above and below a diaphragm by the diaphragm. A single suction port
and a single discharge port are provided. First and second
suction-side check valves, which allow the flow of fluid from the
suction port to the pair of pump chambers and do not allow the flow
of fluid in the reverse direction are provided between the pair of
pump chambers, and the suction port. First and second
discharge-side check valves, which allow the flow of fluid from the
pair of pump chambers to the discharge port and do not allow the
flow of fluid in the reverse direction are provided between the
pair of pump chambers and the discharge port (4-valve diaphragm
pump).
[0008] The 4-valve diaphragm pump can basically be configured by
forming recessed parts, which define an upper pump chamber and a
lower pump chamber, in upper and lower housings, which sandwich a
diaphragm, stacking these housings in order, and forming flow
channels which communicates a pair of pump chambers and the suction
and discharges ports, in the upper and lower housings. However,
there is a need for a 4-valve diaphragm pump that ensures liquid
tightness of connecting parts of the flow channels formed over the
upper housing and the lower housing or the liquid tightness of the
suction flow channel and the discharge flow channel, with high
reliability and durability.
SUMMARY
[0009] One exemplary object of the present embodiments is to
provide a 4-valve diaphragm pump that is liquid tight at the
connecting parts of flow channels formed over an upper housing and
a lower housing. A second exemplary object of the present
embodiments is to provide a 4-valve diaphragm pump capable of
ensuring the liquid tightness of a suction flow channel and a
discharge flow channel with high reliability and durability.
[0010] In a present embodiment, a diaphragm pump includes an upper
housing, a diaphragm, and a lower housing which are stacked in
order. Recessed parts are respectively formed in the surfaces of
the upper and lower housings facing the diaphragm to define an
upper pump chamber and a lower pump chamber above and below the
diaphragm. A suction port and a discharge port are formed in the
lower housing to communicate with the lower pump chamber. Branch
channels are formed in the lower housing and the upper housing to
communicate the suction port and the discharge port with the upper
pump chamber. Suction-side check valves are respectively provided
between the suction port and the upper pump chamber and between the
suction port and the lower pump chamber. Discharge-side check
valves are respectively provided between the discharge port and the
upper pump chamber and between the discharge port and the lower
pump chamber. The branch channels include holes formed in either
the upper housing or the lower housing, a protruding cylindrical
part fitted into the hole, and a sealing ring disposed in an
annular gap formed between the hole and the protruding cylindrical
part such that a compressive force is generated radially.
[0011] Although the upper housing can theoretically be composed of
one member, it is practical that the upper housing is composed of
two members in a case where the upper housing is a molded article
made of a resin material. If the upper housing is composed of two
members, a problem occurs in the structure in which the liquid
tightness of the suction flow channel and the discharge flow
channel is ensured. The present embodiments disclose a suitable
liquid-tight structure in a case where the upper housing is
composed of two members.
[0012] In a present embodiment, the upper housing is composed of
two members. The upper housing is composed of a pump chamber plate,
which is stacked on the diaphragm and has a recessed part for
forming an upper pump chamber and a blind plate stacked on the pump
chamber plate. A pair of an inter-plate suction flow channel and an
inter-plate discharge flow channel, which communicates the suction
port and the discharge port with the upper pump chamber, and which
constitute parts of the branch channels is formed between the pump
chamber plate and the blind plate. The inter-plate suction flow
channel and the inter-plate discharge flow channel includes a pair
of protruding parts formed in any one of the pump chamber plate and
the blind plate, a pair of recessed groove parts which are formed
in the other one of the pump chamber plate and the blind plate to
allow the pair of protruding parts to fit thereinto, and a pair of
sealing rings which are disposed in a pair of closed curve gaps
between the pair of protruding parts and the pair of recessed
groove parts such that a compressive force is generated
radially.
[0013] In another embodiment, the upper housing is composed of two
members. The upper housing is composed of an upper plate, which is
stacked on the diaphragm and a pair of lid plates that are members
separate from the upper plate. The upper plate is formed with
recessed parts, which are opened to the front and back of the upper
plate to form the upper pump chamber, and a pair of an open suction
flow channel groove and an open discharge flow channel groove which
communicates with the suction port and the discharge port with the
upper pump chamber. Any one of the upper plates and the pair of lid
plates is formed with protruding parts corresponding to the open
suction flow channel groove and the open discharge flow channel
groove. The other one of the upper plates and the pair of lid
plates is formed with recessed groove parts to allow the pair of
protruding parts to fit thereinto. A pair of sealing rings are
interposed between the protruding parts and the recessed groove
parts such that a compressive force is generated radially.
[0014] In one exemplary embodiment, the protruding parts, the
recessed groove parts, and the sealing rings are elliptical.
[0015] By keeping a compressive force in the stacked direction of
the upper housing, the diaphragm, and the lower housing from being
applied to any of the sealing rings, and allowing a compressive in
a direction (radial direction) orthogonal to the stacked direction
to be applied to the sealing rings, the liquid tightness can be
ensured with high durability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of an exploded state showing
one exemplary embodiment of a diaphragm pump;
[0017] FIG. 2 is a sectional view of the exploded state according
to FIG. 1;
[0018] FIG. 3 is a plan view of an exemplary lower housing;
[0019] FIG. 4 is a sectional view taken along line IV-IV of FIG.
3;
[0020] FIG. 5 is a sectional view taken along line V-V of FIG.
3;
[0021] FIG. 6 is a plan view of an upper housing on the side of a
pump chamber plate;
[0022] FIG. 7 is a plan view of the pump chamber plate on the side
of a recessed part for forming a pump chamber;
[0023] FIG. 8 is an exploded perspective view of a bimorph-type
piezoelectric vibrator;
[0024] FIG. 9 is a perspective view showing the relationship
between the bimorph-type piezoelectric vibrator and a modified
D-type sealing ring;
[0025] FIG. 10 is a plan view of principal parts of the
piezoelectric vibrator;
[0026] FIGS. 11A and 11B are conceptual diagrams, in different
vibrating directions, of a diaphragm of a 4-valve diaphragm pump to
which the one exemplary embodiment is applied;
[0027] FIG. 12 is a perspective view showing another embodiment,
including a section corresponding to FIG. 4;
[0028] FIG. 13 is an enlarged sectional view of principal parts of
the embodiment of FIG. 12;
[0029] FIG. 14 is a perspective view that illustrates a blind plate
of the embodiment of FIG. 12.
[0030] FIG. 15 is a perspective view showing still another
embodiment, including a section corresponding to FIG. 4;
[0031] FIG. 16 is an enlarged sectional view of principal parts of
the embodiment of FIG. 15; and
[0032] FIG. 17 is an enlarged perspective view of the principal
parts of the embodiment of FIG. 15.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Illustrated embodiments are obtained by applying the present
embodiments to a 4-valve diaphragm pump that the present applicant
proposed the principle in Japanese Patent Application No.
2004-154991. One embodiment thereof will be described with
reference to FIGS. 1 to 7. In one exemplary embodiment, the
diaphragm pump has an upper housing 10, a lower housing 20, and a
piezoelectric vibrator 30, and is in the shape of a flat
rectangular parallelepiped as a whole. The upper housing 10 is
composed of a blind plate 101 and a pump chamber plate 102, and all
the blind plate 101, the pump chamber plate 102, and the lower
housing 20 are molded articles made of a resin material.
[0034] The lower housing 20 is a member in the shape of a flat
rectangular parallelepiped, which is most large-sized and has a
complicate shape, among the molded articles. In the lower housing,
a recessed part 20a for forming a pump chamber is formed so as to
be open to the side opposing the piezoelectric vibrator 30, and a
suction port 31 and a discharge port 32, which are molded
integrally and parallel to each other, are formed so as to protrude
from one surface of flat peripheral four surfaces of the lower
housing (refer to FIGS. 1 to 5).
[0035] The lower housing 20 is formed with a suction-side flow
channel 24H communicating with the suction port 31, and a
discharge-side flow channel 25D communicating with the discharge
port 32. Inner ends of the suction-side flow channel 24H and the
discharge-side flow channel 25D are respectively formed with flow
channel enlarged parts 24Ha and 25Da communicating with the
recessed part 20a for forming a pump chamber. Valve-receiving
recessed parts 24Hb and 25Db are respectively formed at the ends of
the flow channel enlarged parts 24Ha and 25Da on the side of the
recessed part 20a for forming a pump chamber.
[0036] A suction-side umbrella unit (suction-side check valve unit)
21U and a discharge-side umbrella unit (discharge-side check valve
unit) 22U are adhesively fixed to the valve-receiving recessed
parts 24Hb and 25Db, respectively. The suction-side umbrella unit
21U and the discharge-side umbrella unit 22U have the same
structure except that their mounting directions are different from
each other. A central part of a unit plate 21a (unit plate 22a)
whose peripheral edge serves as an adhesive joint 21b (adhesive
joint 22b) to be adhered to the valve-receiving recessed part 24Hb
(valve-receiving recessed part 25Db) is formed with an umbrella
mounting hole 21c (umbrella mounting hole 22c), and a peripheral
edge of the umbrella mounting hole 21c (umbrella mounting hole 22c)
is formed with a plurality of flow channel holes 21d (flow channel
holes 22d).
[0037] An umbrella part 21g (umbrella part 22g) of an umbrella 21f
(umbrella 22f) whose central shaft 21e (central shaft 22e is
mounted into the umbrella mounting hole 21c (umbrella mounting hole
22c) plugs up the flow channel holes 21d (flow channel holes 22d)
normally. When a pressure beyond a rated value is applied to the
umbrella part 21g (umbrella part 22g) from the flow channel holes
21d (flow channel holes 22d) side, the umbrella part 21g (umbrella
part 22g) deforms elastically, and thus the flow channel holes 21d
(flow channel holes 22d) are opened.
[0038] In the suction-side umbrella unit 21U or the discharge-side
umbrella unit 22U, the adhesive joint 21b (22b) is adhesively fixed
to the valve-receiving recessed part 24Hb or 25Db, with their front
and back reversed. The suction-side umbrella unit 21U allows the
flow of fluid from the suction port 31 to the recessed part 20a for
forming a pump chamber (pump chamber 23), and does not allow the
flow of fluid reverse thereto, and the discharge-side umbrella unit
22U allows the flow of fluid from the recessed part 20a for forming
a pump chamber (pump chamber 23) to the discharge port 32, and does
not allow the flow of fluid reverse thereto. The unit plates 21a
and 22a of the suction-side and discharge-side umbrella units 21U
and 22U may be formed as one substrate.
[0039] The lower housing 20, which is a single body that does not
require a lid as a separate body, is formed with the suction-side
flow channel 24H and the discharge-side flow channel 25D, which are
closed between the suction port 31 and the recessed part 20a for
forming a pump chamber and between the discharge port 32 and the
recessed part 20a for forming a pump chamber. The lower housing 20
is formed with a sealing ring groove 20b, which is located around
the recessed part 20a for forming a pump chamber. The sealing ring
groove 20b is in the shape of a modified letter "D" having a large
circular-arc part 20b1 that is a partial circle larger than a
semicircle, and a straight part 20b2 whose connects both ends of
the large circular-arc part 20b1 together by a straight line.
[0040] The suction-side umbrella unit 21U and the discharge-side
umbrella unit 22U, i.e., the valve-receiving recessed parts 24Hb
and 25Db (umbrella parts 21g and 22g) are inclined (non-parallel)
with respect to the plane of a piezoelectric vibrator 300. When a
plane orthogonal to the piezoelectric vibrator 30, including the
axis of the suction port 31 (discharge port 32), is considered, the
inclined direction is a direction in which the plane is separated
apart from the piezoelectric vibrator 30 as it goes toward the
inner end of the suction port 31 (discharge port 32) and approaches
the piezoelectric vibrator as it goes to the near side. If the
suction-side umbrella unit 21U and the discharge-side umbrella unit
22U are inclined in this way, the lower housing 20 can be made thin
without sacrificing the channel sectional area of the suction port
31 and the discharge port 32.
[0041] For example, as shown in FIG. 4, the surface (unit plate 21a
(umbrella part 21g) of the suction-side umbrella unit 21U) of the
valve-receiving recessed part 24Hb and the plane of the
piezoelectric vibrator 30 in a free state, which are non-parallel,
forms an angle .alpha.. A flow channel in a suction-side check
valve (suction-side umbrella unit 21U) is not orthogonal to the
piezoelectric vibrator 30. The axis of the suction port 31
(suction-side flow channel 24H) is parallel to the plane of the
piezoelectric vibrator 30. The direction of the angle .alpha. is a
direction in which the unit plate 21a (umbrella part 21g) of the
suction-side umbrella unit 21U is separated from the piezoelectric
vibrator 30 as it goes toward the inner end (left side of FIG. 4)
of the suction port 31 (suction-side flow channel 24H), and
approaches the piezoelectric vibrator 30 as it goes to the near
side (right side of FIG. 4).
[0042] As shown in FIG. 5, the surface (unit plate 22a (umbrella
part 22g) of the discharge-side umbrella unit 22U) of the
valve-receiving recessed part 24Db and the plane of the
piezoelectric vibrator 30 in a free state, which are non-parallel,
forms an angle .alpha.. For example, a flow channel in a
discharge-side check valve (discharge-side umbrella unit 22U) is
not orthogonal to the piezoelectric vibrator 30. The axis of the
discharge port 32 (discharge-side flow channel 24D) is parallel to
the plane of the piezoelectric vibrator 30. The direction of the
angle .alpha. is a direction in which the unit plate 22a (umbrella
part 22g) of the discharge-side umbrella unit 22U is separated from
the piezoelectric vibrator 30 as it goes toward the inner end (left
side of FIG. 5) of the discharge port 32 (discharge-side flow
channel 25D), and approaches the piezoelectric vibrator 30 as it
goes to the near side (right side of FIG. 5).
[0043] The lower housing 20 is further formed with branch channels
24Hd and 25Dd, which branch from the suction-side flow channel 24H
and the discharge-side flow channel 25D, and which are opened
toward the pump chamber plate 102 (upper housing 10). The pump
chamber plate 102 is formed with communicating holes (branch
channel) 41 and 42 communicating with the branch channels 24Hd and
25Dd. An inter-plate suction flow channel 14H and an inter-plate
discharge flow channel 15D communicating with the communicating
holes 41 and 42, are formed between the blind plates 101 and the
pump chamber plate 102 which constitute the upper housing 10. For
example, the pump chamber plate 102 is formed with protruding
cylindrical parts 41a and 42a which fit into the branch channels
24Hd and 25Dd, and the communicating holes 41 and 42 are formed in
the centers of the protruding cylindrical parts 41a and 42a.
[0044] Open ends of the branch channels 24Hd and 25Dd of the lower
housing 20 are respectively formed with large-diameter stepped
parts 24He and 25De, which have a larger diameter than the outer
diameter of the protruding cylindrical parts 41a and 42a. When the
protruding cylindrical parts 41a or 42a are fitted into branch
channels 24Hd or 25Dd, as shown in FIGS. 4 and 5, an annular gap
41c or 42c is formed between the protruding cylindrical part 41a or
42a, and the large-diameter stepped part 24He or 25De. An O-ring
(sealing ring) 41b or 42b is inserted into the annular gap 41c or
42c.
[0045] The inner diameter of the O-ring 41b or 42b is set to be
smaller than the outer diameter of the protruding cylindrical part
41a or 42a, and the outer diameter thereof is set to be greater
than the large-diameter stepped part 24He or 25De. The O-ring is
kept in a state where it is brought into close contact with the
protruding cylindrical part 41a or 42a and large-diameter stepped
part 24He or 25De, thereby generating compressive force in its
radial direction. For example, the O-ring 41b or 42b keeps a space
between the branch channel 24Hd or 25Dd and the protruding
cylindrical part 41a or 42a (communicating hole 41 or 42)
liquid-tight.
[0046] The length (thickness) d1 (FIG. 4 or FIG. 5) of the annular
gap 41c or 42c in the stacked direction is set to be greater than
the thickness (diameter of a section) of the O-ring 41b or 42b.
This length d1 is ensured uniformly. For example, when the
protruding cylindrical parts 41a and 42a are respectively inserted
into the branch channels 24Hd and 25Dd, an entrance regulating
surface 41d or 42d of the pump chamber plate 102 abuts on an
abutting surface 24Hi or 25Di, which faces the entrance regulating
surface 41d or 42d. The insertion (entrance) position of the
protruding cylindrical part 41a or 42a is regulated. The O-ring 41b
or 42b does not receive a compressive force in the stacked
direction from the lower housing 20 and the pump chamber plate 102.
Any force that makes the lower housing 20 and the pump chamber
plate 102 separated in the stacked direction from the O-rings 41b
and 42b is not applied to the lower housing and the pump chamber
plate.
[0047] Since a compressive force that is uniform as a whole is
applied to the piezoelectric vibrator 30 from the stacked
direction, vibration of the piezoelectric vibrator 30 is also
uniformly generated in the stacked direction. The operation of the
piezoelectric vibrator 30 can be stabilized, and a fluid can be
generated efficiently.
[0048] The surface of the pump chamber plate 102, which faces
piezoelectric vibrator 30 becomes a recessed part 40a for forming a
pump chamber (FIGS. 2, 4, and 5). A substantially central part of
the pump chamber plate is mounted with a suction-side umbrella 11
and a discharge-side umbrella 12 respectively corresponding to the
suction-side umbrella unit 21U and the discharge-side umbrella unit
22U. The suction-side umbrella 11 and the discharge-side umbrella
12 are not drawn on FIG. 2. For example, in the positions
vertically corresponding to the suction-side umbrella unit 21U and
the discharge-side umbrella unit 22U, the pump chamber plate 102 is
formed with umbrella mounting holes 11a and 12a. The peripheral
edges of the umbrella mounting holes 11a and 12a are respectively
formed with a plurality of flow channel holes 11b or 12b.
[0049] The suction-side umbrella 11 or the discharge-side umbrella
12 has a central shaft 11c (central shaft 12c), which is mounted to
the umbrella mounting hole 11a (umbrella mounting hole 12a), and an
umbrella part 11d (umbrella part 12d) which plugs up the flow
channel holes 11b (flow channel holes 12b) normally. When a
pressure beyond a rated value is applied to the umbrella part 11d
(umbrella part 12d) from the flow channel holes 11b (flow channel
holes 12b) side, the umbrella part 11d (umbrella part 12d) deforms
elastically to open the flow channel holes 11b (flow channel holes
12b).
[0050] The suction-side umbrella 11 allows the flow of fluid from
the blind plate 101 side to the recessed part 40a for forming a
pump chamber (pump chamber 13), and does not allow the flow of
fluid reverse thereto, but the discharge-side umbrella 12 allows
the flow of fluid from the recessed part 40a for forming a pump
chamber (pump chamber 13) to the blind plate 101 side, and does not
allow the flow of fluid reverse thereto.
[0051] The blind plate 101 has substantially the same planar shape
as the lower housing 20 so as to overlap the lower housing 20. The
blind plate 101 is formed with a recessed part 14Ha, which forms an
inter-plate suction flow channel 14H that communicates a
communicating hole 41 with the suction-side umbrella 11, and a
recessed part 15Da for forming an inter-plate discharge flow
channel 15D that communicates a communicating hole 42 with the
discharge-side umbrella 12, between itself and the pump chamber
plate 102 (refer to FIG. 2 and FIGS. 4 to 6). Sealing ring grooves
14Hb and 14Dc for allowing elliptical O-rings (sealing rings) 15Da
and 15Da to be fitted thereinto are formed around the recessed
parts 14Ha and 15Da, respectively. The blind plate 101 is also
formed with a recessed part 10a (FIGS. 2 and 6) for allowing the
pump chamber plate 102 to be fitted thereinto.
[0052] The pump chamber plate 102 and the blind plate 101 are
respectively formed with positioning fitting protrusions 40c and
fitting holes 10c (FIG. 1) which are fitted to each other in a
state where the elliptical O-ring 14Hb and 15Db are fitted into the
recessed parts 14Ha and 15Da, for example, respectively. By bonding
the positing fitting protrusions and the fitting holes together
after they are fitted to each other, the liquid-tight inter-plate
suction flow channel 14H that is liquid-tight from the
communicating hole 41 to the suction-side umbrella 11 and the
inter-plate discharge flow channel 15D which is liquid-tight from
the discharge-side umbrella 12 to the communicating hole 42 are
formed. For example, the positioning fitting protrusions 40c are
fitted into the recessed parts 10a, for example, respectively, so
that the blind plate 101 and the pump chamber plate 102 may be
integrated in advance, thereby forming the inter-plate suction flow
channel 14H and the inter-plate discharge flow channel 15D which
are closed therebetween. Lid members other than the blind plate 101
and the pump chamber plate 102 in forming the inter-plate suction
flow channel 14H and the inter-plate discharge flow channel 15D are
not needed.
[0053] As shown in FIG. 7, a sealing ring groove 40b corresponding
to (having the same shape in plan view) the sealing ring groove 20b
of the lower housing 20 is formed around the recessed part 40a for
forming a pump chamber, which faces the piezoelectric vibrator 30,
in the pump chamber plate 102. The sealing ring groove 40b is in
the shape of a modified letter "D" having a large circular-arc part
40b1 that is a partial circle larger than a semicircle, and a
straight part 40b2 whose connects both ends of the large
circular-arc part 40b1 together by a straight line.
[0054] Both of a unimorph-type piezoelectric vibrator and a
bimorph-type piezoelectric vibrator can be used as the
piezoelectric vibrator 30. FIGS. 8 to 10 are schematic views of one
embodiment of the bimorph-type piezoelectric vibrator, which is
proposed in Patent Application No. 2004-192483 by the present
applicant. This piezoelectric vibrator is provided with a circular
shim 111 at the central part thereof, and piezoelectric elements
112 which are stacked on the front and back thereof. The shim 111
is made of a conductive metallic thin plate material, for example,
a stainless steel thin plate having a thickness of about 0.2
mm.
[0055] The piezoelectric elements 112 are made of, for example, PZT
(Pb(Zr, Ti)O.sub.3) having a thickness of about 3 mm, and they are
subjected to polarizing treatment in the direction of the front and
back thereof. This polarizing treatment is performed in the same
direction in the pair of piezoelectric elements 112 located at the
front and back of the shim 111. For example, referring to FIG. 8,
when the polarization direction of the pair of piezoelectric
elements 112 are denoted by arrow "a" or "b", the polarizing
treatment in the same direction as the thickness direction of the
shim 111 is performed. The pair of front and back piezoelectric
elements 112 in contact with the shim 111 exhibits polarization
characteristics of different poles, respectively, and the exposed
surfaces of the pair of piezoelectric elements 112 become different
poles, respectively. If the front and back piezoelectric elements
112 are allowed to have the polarization characteristic of the same
direction in this way, the displacement of the shim 111 can be
increased when positive and negative voltages are applied
alternately between the shim 111 and the exposed surfaces of the
pair of piezoelectric elements 112 at the front and back of the
shim 111.
[0056] The whole surfaces of the piezoelectric elements 112 on the
side of the pair of shims 111 are adhered to the shim 111 so as to
be electrically connected thereto, and a filmy electrode 113 is
formed on each of the whole exposed surfaces of the piezoelectric
elements opposite to the shim 111. The filmy electrode 113 is
formed, for example, by printing (screen-baking) conductive paste
(silver paste).
[0057] A power supply terminal 180 has a pair of contactors 1811, a
connection line 1812 which connects the contactors 1811 to each
other, and a wiring connection 1813. The pair of contactors 1811
and the connection line 1812 forms a U-shaped section. The pair of
contactors 1811 has the same configuration having a substantially
triangular part in plan view that is broader on the side of the
wiring connection 1813 located outside the piezoelectric vibrator
30, and becomes gradually narrower toward the central part of the
piezoelectric vibrator 30. For example, each contactor 1811 is the
narrowest on the side of a part 1131 soldered to the filmy
electrode 113 of the piezoelectric vibrator 30, and increases in
width toward the outside of the piezoelectric vibrator 30.
[0058] A wiring connecting projection 114, which is formed in the
shim 111 of the piezoelectric vibrator 30 and projects in the
radial direction extends between the pair of contactors 1811. This
wiring connecting projection 114 is formed with an insulating
recessed part 1141, which ensures a gap from the connection line
1812 that connects the pair of contactors 1811 to each other.
[0059] A pair of annular spacer insulating rings 115 are located
above and below the circular shim 111, for example, respectively,
and striped insulating plate materials 1151 extends to between the
pair of contactors 1811 and the wiring connecting projection 114
from the pair of spacer insulating rings 115 so that the
short-circuiting between the shim 111 and the power supply terminal
180 can be prevented. Each striped insulating plate material 1151
prevents the connection line 1812 of the power supply terminal 180
from moving toward the insulating recessed part 1141 of the shim
111, thereby ensuring insulation.
[0060] The wiring connecting projection 114 of the shim 111 is
formed with a pair of lead wire latching recessed parts 1143 and
1144 which are located further outside the piezoelectric vibrator
30 than the insulating recessed part 1141 and which are symmetrical
with respect to each other on both sides of the wiring connecting
projection 114 in the width direction thereof, and a soldering
through hole 1145 is formed inwardly from one lead wire latching
recessed part 1143.
[0061] The wiring connection 1813 of the power supply terminal 180
is formed with a soldering through hole 1814 corresponding to the
soldering through hole 1145 of the wiring connecting projection
114. The soldering through holes 1145 and 1814 are different in
positions in plan view, and soldered to lead wires 211 and 221, for
example, respectively. Since the soldering through holes 1145 and
1814 increase soldering strength and are made different in
positions in plan view, the whole diaphragm pump can be made thin.
The lead wires 211 and 221 are hung on the lead wire latching
recessed parts 1143 and 1144, thereby increasing resistance against
falling-off of the lead wires 211 and 221.
[0062] A PPS film (insulating films) 116 (FIG. 8) is adhered to
each surface of the piezoelectric vibrator 30. The PPS film 116 has
a radial tongue piece 116a which extends onto the power supply
terminal 180 to prevent disengagement between the contactors 1811
and the filmy electrode 113 of the piezoelectric vibrator 30.
[0063] According to the wiring structure in the vicinity of the
wiring connecting projection 114 of the shim 111 and the power
supply terminal 180 which have been described hitherto, wiring to
the shim 111 and the filmy electrode 113 can be surely attained
without obstructing movement of the piezoelectric vibrator 30.
[0064] The piezoelectric vibrator 30 whose basic shape is a planar
circular shape as described above is sandwiched between the
recessed part 20a for forming a pump chamber of the lower housing
20 and the recessed part 40a for forming a pump chamber of the pump
chamber plate 102. The upper and lower peripheries of the
piezoelectric vibrator are sealed with the sealing rings 16 and 26
to form the pump chambers 13 and 23. The sealing rings 16 and 26
have the same shape as the sealing ring groove 20b of the lower
housing 20 and the sealing ring groove 40b of the pump chamber
plate 102, and have the large circular-arc part 16a (large
circular-arc part 26a) and the straight part 16b (straight part
26b). The power supply terminal 180 of the piezoelectric vibrator
30 is located outside the sealing rings 16 and 26, i.e., outside
the straight part 16b (straight part 26b). Since this arrangement
prevents intersection of the power supply terminal 180 to the
piezoelectric elements 112 of the piezoelectric vibrator 30 with
the sealing rings 16 and 26 and local deformation of the sealing
rings 16 and 26, the durability can be improved.
[0065] The lower housing 20, and the blind plate 101 integrated in
advance into the pump chamber plate 102 are combined with each
other and integrated into one by fasteners (for example, bolt and
nut), with the piezoelectric vibrator 30 sandwiched between the
lower housing and blind plate, as described above. In an alternate
embodiment, an adhesive can be used additionally.
[0066] In the diaphragm pump having the above configuration, when
alternating electric fields are applied to between the power supply
terminal 180 and the shim 111 (wiring connecting projection 114) to
elastically deform (vibrate) the piezoelectric vibrator 30 forward
and backward, the volume of one of the pump chambers 13 and 23
increases, and the volume of other one decreases. During the stroke
in which the volume of the pump chamber 13 increases, since the
suction-side umbrella 11 opens and a fluid flows into the pump
chamber 13 from the suction port 31 and simultaneously the volume
of the pump chamber 23 decreases, the fluid in the pump chamber 23
opens the discharge-side umbrella (unit) 22, and flows into the
discharge port 32.
[0067] During the stroke in which the volume of the pump chamber 13
decreases, since the suction-side umbrella (unit) 21 opens and a
fluid flows into the pump chamber 23 from the suction port 31, and
the volume of the pump chamber 13 decreases, the fluid in the pump
chamber 13 opens the discharge-side umbrella 12 and flows into the
discharge port 32. The cycle of the pulsation in the discharge port
32 can be shortened (reduced to half as compared with a case where
a pump chamber is formed only in one of the upper and lower sides
of the piezoelectric vibrator 30). Flow channels of the
above-described 4-valve diaphragm pump are skeletonized in FIG.
1.
[0068] FIGS. 12 to 14 illustrate an alternate embodiment of the
diaphragm pump. The present embodiment is configured such that,
even in the seal structure in the vicinity of the inter-plate
suction flow channel 14H and the inter-plate discharge flow channel
15D, which are formed between the blind plate 101 and the pump
chamber plate 102 (in the upper housing 10), a force in the
direction in which the blind plate 101 and are separated from the
pump chamber plate 102 is kept from being applied.
[0069] For example, instead of the sealing ring groove 14Hc and
15Dc, a pair of recessed groove parts 101b1 and 101b2 are
respectively formed around the recessed parts 14Ha and 15Da of the
blind plate 101, as shown in the enlarged view of FIG. 13.The pump
chamber plate 102 is formed with a pair of elliptical protruding
parts 101b1 and 102b1 which are caused to project toward the blind
plate 101 and fit into a pair of recessed groove parts 101b1 and
102b2, for example, respectively. When the pair of protruding parts
102b1 and 102b2 and the pair of recessed groove part 101b1 and
101b2 are caused to fit into each other, a pair of closed curve
gaps 141c and 142c are formed therebetween.
[0070] Sealing rings 141b and 142b are inserted into the pair of
closed curve gaps 141c and 142c, for example, respectively. When
the sealing rings 141b and 142b are inserted into the pair of
closed curve gaps 141c and 142c, a compressive force is generated
in the radial direction (the direction in the plane of the blind
plate 101 and the pump chamber plate 102). For example, the spaces
between the blind plate 101 and the pump chamber plates 102 are
held in liquid tightness by the sealing rings 141b and 142b.
[0071] The length (thickness) d2 (FIGS. 12 and 13) of the pair of
closed curve gaps 141c and 142c in the stacked direction of
housings is set to be greater than the thickness (diameter of a
section) of the sealing rings 141b and 142b. This length d2 is
ensured uniformly. For example, when the pair of protruding parts
102b1 and 102b2 are inserted into the pair of recessed groove parts
101b1 and 101b2, respectively, entrance regulating surfaces 102a1
and 102a2 of the pump chamber plate 102 abut on abutting surfaces
101a1 and 101a2, respectively, thereby regulating the insertion
(entrance) position of the protruding parts. The sealing rings 141b
and 142b do not receive a compressive force in the stacked
direction from the blind plate 101 and the pump chamber plate 102.
Any force that makes the blind plate 101 and the pump chamber plate
102 separated in the stacked direction from the sealing ring 141b
and 142b is not applied to the blind plate and the pump chamber
plate. Since a compressive force that is uniform as a whole is
applied to the piezoelectric vibrator 30 from the stacked
direction, vibration of the piezoelectric vibrator 30 is also
uniformly generated in the stacked direction. The operation of the
piezoelectric vibrator 30 can be stabilized, and a fluid can be
generated efficiently.
[0072] FIGS. 15 to 17 show still another embodiment of the
diaphragm pump. This embodiment is an embodiment in which the upper
housing 10 is composed of an upper plate 103 and a pair of lid
plates 104H and 104D, a suction flow channel 14H1 is formed between
this upper plate 103 and the lid plate 104H, and a discharge flow
channel 15D1 is formed between the upper plate 103 and the lid
plate 104D.
[0073] Any force in the direction in which both are separated from
each other (force in the direction in which the upper plate 103 and
the lid plate 104H (lid plate 104D) are separated from each other)
is kept from being applied by the seal structure between the upper
plate 103 and the lid plates 104H and between the upper plate 103
and the lid plate 104D. For example, the upper plate 103 is formed
with an open suction flow channel groove 103b1 and an open
discharge flow channel groove 103b2 whose top are opened. An inside
end of the open suction flow channel groove 103b1 is provided with
an umbrella 11, and an outside end thereof is provided with a
branch channel 41.
[0074] Although not shown in FIG. 15, an inside end of the open
discharge flow channel groove 103b2 is provided with an umbrella
12, and an outside end thereof is provided with a branch channel
42. Alternatively, the pair of lid plates 104H and 104D is provided
with protruding parts 104b1 and 104b2, respectively, which project
toward the upper plate 103 and fit into the open suction flow
channel groove 103b1 and the open discharge flow channel groove
103b2.
[0075] When the protruding parts 104b1 and 104b2 are caused to fit
into the open suction flow channel groove 103b1 and the open
discharge flow channel groove 103b2, respectively, closed curve
gaps 241c and 242c are formed therebetween, as shown in the
enlarged view of FIG. 16. The sealing rings 241b and 242b are
inserted into the closed curve gaps 241c and 242c, respectively, to
form a liquid-tight suction flow channel 14H1 and a liquid-tight
discharge flow channel 15D1. When the sealing rings 241b and 242b
are inserted into the pair of closed curve gaps 241c and 242c,
respectively, a compressive force is generated in the radial
direction (the direction in the plane of the pair of lid plates
104H and 104D and the upper plate 103). For example, the spaces
between the pair of lid plates 104H and 104D, and the upper plate
103 are held in liquid tightness by the sealing rings.
[0076] The length d3 (FIGS. 15 and 16) of the closed curve gaps
241c and 242c in the stacked direction is set to be greater than
the thickness (diameter of a section) of the sealing rings 241b and
242b. This length d3 is ensured uniformly. For example, when the
pair of protruding parts 104b1 and 104b2 are inserted into the open
suction flow channel groove 103b1 and the open discharge flow
channel groove 103b2, respectively, entrance regulating surfaces
104a1 and 104a2 of the pair of lid plates 104H and 104D abut on
abutting surfaces 103a1 and 103a2, respectively, thereby regulating
the insertion (entrance) position of the protruding parts.
[0077] The sealing ring 241b or 242b does not receive a compressive
force in the stacked direction from the upper plate 103 and the
pair of lid plates 104H and 104D. For example, any force that makes
the upper plate 103 and the pair of lid plates 104H and 104D
separated in the stacked direction from the sealing ring 241b and
242b is not applied to the upper plate and the lid plates.
Accordingly, since a compressive force that is uniform as a whole
is applied to the piezoelectric vibrator 30 from the stacked
direction, vibration of the piezoelectric vibrator 30 is also
uniformly generated in the stacked direction. Therefore, the
operation of the piezoelectric vibrator 30 can be stabilized, and a
fluid can be generated efficiently.
[0078] The present embodiments are aimed at the seal structure,
which ensures the liquid tightness of the suction flow channel and
discharge flow channel of the above embodiment, with high
durability. The lower housing, the umbrella, or the piezoelectric
vibrator only shows an example. Accordingly, although the umbrella
is illustrated as a check valve, check valves other than the
umbrella can also be used, and an electrostrictive vibrator may be
used instead of the piezoelectric vibrator. Further, the present
invention can also be applied to a 2-valve type diaphragm pump,
i.e., a pump in which a pump chamber is formed only below a
piezoelectric vibrator, and any pump chamber is not provided above
the piezoelectric vibrator (an umbrella is not provided).
[0079] According to the present embodiments, in a 4-valve diaphragm
pump, the liquid tightness of the connecting parts of the flow
channels formed over the upper housing and the lower housing can be
ensured with high reliability and durability. The liquid tightness
of the suction flow channel and discharge flow channel formed in
the upper housing can be ensured with high reliability and
durability.
* * * * *