U.S. patent application number 11/375214 was filed with the patent office on 2006-09-21 for fluid pump.
This patent application is currently assigned to Aisin Seiki Kabushiki Kaisha. Invention is credited to Yoshiaki Nakano.
Application Number | 20060210394 11/375214 |
Document ID | / |
Family ID | 36600220 |
Filed Date | 2006-09-21 |
United States Patent
Application |
20060210394 |
Kind Code |
A1 |
Nakano; Yoshiaki |
September 21, 2006 |
Fluid pump
Abstract
A fluid pump includes a housing, an intake port, a discharge
port, a fluid chamber, a rotation shaft, an impeller supported by
the rotation shaft so as to be rotatable in order to discharge
fluid, the impeller includes a supported plate, plural blade
portions provided at the impeller so as to be erected on a surface
of the supported plate, a first inner end formed on each of the
blade portions at a radially inner end thereof, plural notch
portions formed on the supported plate of the impeller so as to be
recessed inwardly, a second inner end formed on each of the notch
portions at a radially inner end thereof and located at least
radially outward relative to the first inner end and the notch
portion provided at front of the blade portion in a rotation
direction of the impeller.
Inventors: |
Nakano; Yoshiaki;
(Toyohashi-shi, JP) |
Correspondence
Address: |
REED SMITH LLP;Suite 1400
3110 Fairview Park Drive
Falls Church
VA
22042
US
|
Assignee: |
Aisin Seiki Kabushiki
Kaisha
|
Family ID: |
36600220 |
Appl. No.: |
11/375214 |
Filed: |
March 15, 2006 |
Current U.S.
Class: |
415/206 |
Current CPC
Class: |
F04D 29/2255 20130101;
F01P 2005/125 20130101; F04D 29/2272 20130101; F04D 29/2216
20130101 |
Class at
Publication: |
415/206 |
International
Class: |
F04D 29/44 20060101
F04D029/44 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 17, 2005 |
JP |
2005-076983 |
Claims
1. A fluid pump comprising a housing; an intake port provided at
the housing; a discharge port provided at the housing; a fluid
chamber provided inside the housing so as to connect to the intake
port and the discharge port; a rotation shaft provided inside the
housing; an impeller provided inside the fluid chamber and
supported by the rotation shaft so as to be rotatable in order to
discharge fluid by means of the rotation of the impeller from the
discharge port which is provided radially outside of the impeller;
a supported plate provided at the impeller and supported by the
rotation shaft so as to be rotatable along a backside wall of the
fluid chamber; plural blade portions provided at the impeller so as
to be erected on a surface of the supported plate in the opposite
side of the backside wall in a manner where it extends in a radial
direction of the supported plate; a first inner end formed on each
of the blade portions at a radially inner end thereof; plural notch
portions formed on the supported plate of the impeller so as to be
recessed inwardly from a radially outer end of the supported plate;
a second inner end formed on each of the notch portions at a
radially inner end thereof; the second inner end being located at
least radially outward relative to the first inner end; and the
notch portion provided at front of the blade portion in a rotation
direction of the impeller.
2. The fluid pump according to claim 1, wherein each notch portion
is formed at an area, which is located front of the blade portion
in a rotation direction of the impeller, so as to abut on the blade
portion.
3. The fluid pump according to claim 1, wherein a length of the
notch portion in a circumferential direction of the impeller is set
in a manner where it becomes larger as it is located radially
outward.
4. The fluid pump according to claim 1, wherein the second inner
end is located radially inward relative to a central position of
the blade portion in a radial direction thereof.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
U.S.C. .sctn. 119 to Japanese Patent Application 2005-076983, filed
on Mar. 17, 2005, the entire content of which is incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a fluid pump including a
housing, an intake port, a discharge port, a fluid chamber, a
rotation shaft and an impeller.
BACKGROUND
[0003] A known fluid pump includes a housing, an intake port, a
discharge port, a fluid chamber, a rotation shaft and an impeller.
Specifically, the fluid chamber is provided inside the housing so
as to connect to the intake port and the discharge port, and the
impeller is provided inside the fluid chamber and supported by the
rotation shaft so as to be rotatable. In this configuration, the
fluid pump discharges fluid from the discharge port that is
provided outside of the impeller in a radial direction thereof by
means of the rotation of the impeller. Such fluid pump is used for
an automobile in order to circulate coolant.
[0004] More specifically, the fluid pump intakes fluid such as
coolant from the intake port, which is provided in an axial
direction of the rotation shaft, and the fluid is discharged by
means of centrifugal force caused by the rotation of the impeller
from the discharge port, which is provided at the outside of the
impeller in its radial direction.
[0005] A known fluid pump disclosed in JP2000-104548 is comprised
of an impeller including a circular cylinder-type fluid chamber, a
supported plate and plural blade portions. Specifically, the
circular cylinder-type fluid chamber is provided inside a housing,
the supported plate is supported by a rotation shaft so as to be
rotatable along a back side wall of a fluid chamber, and each of
the blade portions is erected on a one surface, which is opposed to
the other surface facing to a back side wall of the supported
plate, so as to extend in a radial direction of the supported
plate.
[0006] According to the known fluid pump, the blade portion applies
centrifugal force to the fluid by means of the rotation of the
impeller, as a result, the supported plate guide the fluid so as to
flow in a radial outer direction of the impeller.
[0007] In the fluid chamber, a space is formed between a radial
outer end of the impeller and an outer peripheral wall portion of
the fluid chamber. Specifically, the fluid flows within the space
between the radial outer end and the outer peripheral wall in a
radial outer direction of the impeller toward the discharge
port.
[0008] According to the known fluid pump, when a distance between
the radial outer end of the impeller and outer peripheral wall
portion of the fluid chamber is reduced in order to downsize the
fluid pump, because a volume of the space formed between the radial
outer end of the impeller and the outer peripheral wall portion of
the fluid chamber becomes small, a value of pressure applied to the
fluid increases, as a result, the pressure applied to the fluid
becomes larger than centrifugal force generated by the blade
portion of the impeller. Further, the fluid may flows in an
opposite direction of the radially inward direction of the
impeller, which causes performance decrement of the fluid pump in
terms of total dynamic head and efficiency.
[0009] A need thus exists to provide a downsized fluid pump having
small performance decrement.
SUMMARY OF THE INVENTION
[0010] According to an aspect of the present invention, a fluid
pump includes a housing, an intake port provided at the housing, a
discharge port provided at the housing, a fluid chamber provided
inside the housing so as to connect to the intake port and the
discharge port, a rotation shaft provided inside the housing, an
impeller provided inside the fluid chamber and supported by the
rotation shaft so as to be rotatable in order to discharge fluid by
means of the rotation of the impeller from the discharge port which
is provided radially outside of the impeller, a supported plate
provided at the impeller and supported by the rotation shaft so as
to be rotatable along a backside wall of the fluid chamber, plural
blade portions provided at the impeller so as to be erected on a
surface of the supported plate in the opposite side of the backside
wall in a manner where it extends in a radial direction of the
supported plate, a first inner end formed on each of the blade
portions at a radially inner end thereof, plural notch portions
formed on the supported plate of the impeller so as to be recessed
inwardly from a radially outer end of the supported plate, a second
inner end formed on each of the notch portions at a radially inner
end thereof, the second inner end being located at least radially
outward relative to the first inner end, and the notch portion
provided at front of the blade portion in a rotation direction of
the impeller.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The foregoing and additional features and characteristics of
the present invention will become more apparent from the following
detailed description considered with reference to the accompanying
drawings, wherein:
[0012] FIG. 1 illustrates a cross section indicating a fluid
pump;
[0013] FIG. 2 illustrates a cross section seen from II-II line.
[0014] FIG. 3 illustrates positions of a radial inner end of a
notch portion used for a test;
[0015] FIG. 4 illustrates a graph indicating results of total
dynamic head of the fluid pump obtained by the test; and
[0016] FIG. 5 illustrates a graph indicating results of efficiency
of the fluid pump obtained by the test.
DETAILED DESCRIPTION
[0017] An embodiment of a fluid pump according to the present
invention will be explained in accordance with the attached
drawings. As shown in FIG. 1, the fluid pump includes a housing 1,
an intake port 2, a discharge port 3 and a fluid chamber 4.
Specifically, the fluid chamber 4 is formed inside the housing 1 so
as to connect to the intake port 2, the discharge port 3, a
rotation shaft 5 and an impeller 6. Further, the impeller 6 is
provided inside the fluid chamber 4 so as to be supported by the
rotation shaft 5. In this configuration, fluid sucked from the
intake port into the fluid chamber 4 by means of the rotation of
the impeller 6 is discharged from the discharge port 3.
[0018] The housing 1 includes a first housing 1a and a second
housing 1b. The first housing 1a is made of resin material, and the
intake port 2 and the discharge port 3 are integrally formed at the
first housing 1a. The second housing 1b is also made of a resin
material. The first housing 1a and the second housing 1b are
screwed together by means of a tightening means 7 such as a bolt so
as to form a fluid chamber 4. The fluid chamber 4 includes a small
cylindrical space and a large cylindrical space, whose diameter is
larger than that of the small cylindrical space, so as to form a
stepped portion there between. The rotation shaft 5 is rotatable
supported by the housing 1 in a manner where each end portion of
the rotation shaft 5 is supported by a bearing portion P. The
intake port 2 is formed at the housing 1 so as to extend in an
axial direction of the rotation shaft 5, and the discharge port 3
is formed radially outside of the rotation shaft 5, in other words,
radially outside of the impeller 6.
[0019] The impeller 6 is provided at the rotation shaft 5 at one
end thereof at the side of the intake port 2 along an axial
direction of the rotation shaft 5, and a magnet 8 is provided at an
outer peripheral portion of rotation shaft 5 so as to be further
apart from the intake port 2.
[0020] Coils 9 are provided at the second housing 1b so as to face
the magnet 8. Each coil 9 generates magnetic field in order to
rotate the rotation shaft 5. Specifically, plural coils 9 are
provided at every predetermined angle (e.g., 120 degrees) in a
rotating direction of the impeller. In this configuration, when
each of coils 9 is sequentially controlled so as to be turned "on"
or "off", the rotation shaft 5 is rotated, as a result the impeller
6 is rotated.
[0021] The impeller 6 includes a supported plate 10 and plural
blade portions 11. Specifically, the supported plate 10 is
rotatably supported by the rotation shaft 5 along the stepped
portion 4a serving as a backside wall of the fluid chamber 4. Each
of blade portions 11 is formed so as to be erected on a surface of
the supported plate 10 on the opposite side of the stepped portion
4a and extend in a radial direction of the supported plate 10. The
supported plate 10 and the blade portion 11 are made of resin and
formed integrally.
[0022] As shown in FIG. 2, the supported plate 10 is formed in a
circular shape so as to extend from the rotation shaft 5 in a
radially outward direction. Inside the fluid chamber 4, a space K,
in which fluid flows, is formed between the radial outer end 10a of
the supported plate 10 and the outer peripheral wall portion 4b of
the fluid chamber 4. The space K is formed in an approximately
volute shape in a rotating direction W of the impeller 6, in other
words, the space K becomes large as the radial outer end 10a of the
supported plate 10 becomes close to the position of the discharge
port 3. Each of blade portions 11 extends from a position apart
from the rotation shaft 5 in a radially outward direction to a
position of the radial outer end 10a of the supported plate 10 in a
manner where the radial outer end 10a is positioned rear in the
rotating direction W of the impeller 6.
[0023] Plural notch portions 12 are formed on the supported plate
10 in a manner where each of which recessed in a radially inward
direction. Each notch portion 12 has a radial inner end 12a (e.g.,
serving as a second inner end) which is positioned radially outward
relative to a radial inner end 11a (e.g., serving as a first inner
end) of the blade portion 11.
[0024] Each of notch portions 12 is formed at front of each of
blade portions 11 in a rotating direction of the impeller 6 within
a predetermined range. A length H of the notch portion 12 in a
circumferential direction of the impeller 6 is set in a manner
where it becomes larger as it is located radially outward.
[0025] In this configuration, the fluid which is pumped so as to
flow toward the discharge port 3 within not only the space K but
also the spaces at which the notch portions 12 exist, so that
volume in which the fluid flows becomes large.
[0026] Thus, even when the volume of the space K is reduced in
order to downsize the fluid pump itself, chances that the level of
the pressure applied to the fluid becomes large can be reduced.
Further, chances that the fluid flows in a radially inward
direction of the impeller 6 can also be reduced. Further, in this
configuration, because the supported plate 10 is provided inward
relative to the radial inner ends 11a of the blade portions 11 and
rear in the rotating direction of the blade portion 11, chances
that the fluid flows at the side of the back side wall 4a of the
fluid chamber 4 can be reduced. Thus, the fluid pump is downsized
while the performance decrement thereof is reduced.
[0027] Entire pump head and efficiency are measured at fluid pumps
each of which has a radial inner end 12a that is provided at a
different position relative to the blade portion 11, in order to
figure out the best position of the radial inner end 12a.
[0028] As shown in FIG. 3, in this test, the position of the radial
inner end 12a that forms no notch portion 12 is set to K1, the
position of the radial inner end 12a, which is positioned more
inward relative to K1 is set to K2, the position of the radial
inner end 12a, which is positioned more inward relative to K2 is
set to K3, the position of the radial inner end 12a, which is
positioned more inward relative to K3 is set to K4, and the
position of the radial inner end 12a, which is positioned more
inward relative to K4 is set to K5. Further, the position of the
radial inner end 12a, which is positioned further inward relative
to the radial inner end of the blade portion 11 is set to K6. At
the position K2, the radial inner end 12a of the notch portion 12
is positioned radially outward relative to a central position of
the blade portion 11 in a radial direction thereof. At the position
K3, the radial inner end 12a of the notch portion 12 is positioned
at a central position of the blade portion 11 in a radial direction
thereof. At the position K4, the radial inner end 12a of the notch
portion 12 is positioned radially inward relative to the central
position of the blade portion 11 in a radial direction thereof. At
the position K5, the radial inner end 12a of the notch portion 12
is positioned near the radial inner end 11a of the blade portion 11
in a radial direction thereof.
[0029] FIG. 4 illustrates test results of the total dynamic head of
the fluid pump whose position of the radial inner end 12a of the
notch portion 12 is changed to K1, K2, K3, K4, K5 and K6. FIG. 5
illustrates test results of the efficiency of the fluid pump whose
position of the radial inner end 12a of the notch portion 12 is
changed to K1, K2, K3, K4, K5 and K6.
[0030] As shown in FIG. 4 and FIG. 5, both the total dynamic head
and the efficiency increase as the position of the radial inner end
12a of the notch portion 12 is located radially inward relative to
the blade portion 11. However, at the positions K5 located near the
radial inner end 11a of the blade portion and K6 located at the
same position of the radial inner end 11a of the blade portion 11,
both the total dynamic head and the efficiency decrease. Thus, the
fluid pump whose position of the radial inner end 12a of the notch
portion 12 is set at K4, which is located radially inward relative
to a central position of the blade portion 11 in a radial direction
thereof, gives the best performance in terms of both the total
dynamic head and the efficiency.
[0031] Thus, the performance of the fluid pump is improved by
forming the radial inner end 12a of the notch portion 12 in a
manner where it is located radially inward relative to a central
position of the blade portion 11 in a radial direction thereof, and
the radial inner end of the notch portion 12 is located at radially
outward relative to the radial inner end 1 la of the blade portion
11.
[0032] (1) In the above embodiment, as shown in FIG. 2, each notch
portion 12 is formed at front of each blade portion 11 in a
rotating direction thereof at a predetermined area so as to abut on
the blade portion 11, however, each notch portion 12 may be formed
within an entire area between one blade portion 11 and another
blade portion 11.
[0033] (2) In the above embodiment, as shown in FIG. 2, the length
H of the notch portion 12 in a circumferential direction of the
impeller 6 is set in a manner where it becomes larger as it is
located radially outward, however, the value of the length H can be
set flexibly. It can be set so as to be the same at any position in
a radially outward direction.
[0034] (3) In the above embodiment, as shown in FIG. 2, the radial
inner end 12a of the notch portion 12 is located radially inward
relative to a central position of the blade portion 11 in a radial
direction thereof, however, the position of the radial inner end
12a is flexible as far as it is located radially outward relative
to the radial inner end 1 la of the blade portion 11 in a radial
direction thereof.
[0035] (4) In the above embodiment, as shown in FIG. 2, seven blade
portions 11 are provided at the impeller 6 in a manner where each
of which is positioned more rear in the rotating direction W of the
impeller 6 as the blade portion 11 extends in a radially outward
direction, however, the number and the shape of each of the blade
portions 11 may be changed.
[0036] The present invention is not limited to the usage for the
fluid pump for circulating coolant of the automobile and can be
used for various types of fluid pump as long as it has a housing
including a fluid chamber connected to the intake port and the
discharge port, and an impeller is provided in the fluid chamber so
as to be supported by a rotation shaft.
[0037] Because the supported plate includes a notch portion, which
is further recessed in a radially inward direction relative to the
radial outer end of the supported plate, the fluid flows in a
radially outward direction of the impeller within the space formed
between the radial outer end of the impeller and the outer
peripheral wall portion of the fluid chamber, and further flows
toward discharge port within the notch portions connected to the
space.
[0038] The fluid flows within the space formed between the radial
outer end of the impeller and the outer peripheral wall portion of
the fluid chamber, and also flows within the notch portions
connected to the space. Thus, even when the space formed between
the radial outer end and the outer peripheral wall portion is
reduced in order to downsize the fluid pump, because the fluid
still can flows within the notch portions, the pressure applied to
the fluid does not become excessive. Thus, chances that the fluid
flows in the radially inward direction of the impeller is reduced,
as a result, chances of the performance decrement is also
reduced.
[0039] However, because the notch portions are formed on the
impeller, effect that the fluid is guided by means of the supported
plate so as to flow in a radially outward direction of the impeller
is reduced. Thus, according to the present invention, the notch
portions are formed in a manner where the radial inner end of the
notch portion is located radially outward relative to the radial
inner end of the blade portion, and the supported plate is located
at the position of the radial inner end of the blade portion or
radially inner of the radial inner end of the blade portion.
[0040] Thus, the fluid is guided by means of the supported plate so
as to flow in a radially outward direction of the impeller, as a
result, chances that the fluid flows in an opposite direction of
the radially outward direction of the impeller are reduced, and
chances of the performance decrement caused by the existence of the
notch portions are also educed.
[0041] The notch portion is formed at an area, which is located
front of the blade portion in a rotation direction of the impeller,
so as to abut on the blade portion.
[0042] In this configuration, the supported plate exists rear of
the blade portion in a rotation direction of the impeller, as a
result, chances that the fluid flows in a direction of the back
side wall of the fluid chamber are reduced. Further, chances that
the strength reduction of the impeller caused by existence the
notch portions are also reduced.
[0043] A length of the notch portion in a circumferential direction
of the impeller is set in a manner where it becomes larger as it is
located radially outward.
[0044] In this configuration, the notch portion becomes larger at
radially outward portion of the impeller at which higher pressure
is applied to the fluid and connected to the space between the
radial outer end and the outer peripheral wall portion. As a
result, chances that pressure applied to the fluid becomes
excessive are reduced, and chances that the fluid flows in an
opposite direction of a radially outward direction of the impeller
are also reduced.
[0045] The radial inner end of the notch portion is located
radially inward relative to a central position of the blade portion
in a radial direction thereof.
[0046] In other words, each notch portion is formed in a manner
where its radial inner end is located between the central portion
of the blade portion in its radial direction and the radial inner
end of the blade portion. As a result, chances that the fluid flows
in a direction of the backside wall of the fluid chamber are
reduced. Further, chances of performance decrement are reduced.
[0047] The principles, preferred embodiment and mode of operation
of the present invention have been described in the foregoing
specification. However, the invention which is intended to be
protected is not to be construed as limited to the particular
embodiments disclosed. Further, the embodiments described herein
are to be regarded as illustrative rather than restrictive.
Variations and changes may be made by others, and equivalents
employed, without departing from the sprit of the present
invention. Accordingly, it is expressly intended that all such
variations, changes and equivalents which fall within the spirit
and scope of the present invention as defined in the claims, be
embraced thereby.
* * * * *