U.S. patent application number 16/629456 was filed with the patent office on 2020-05-07 for pump.
This patent application is currently assigned to HITACHI AUTOMOTIVE SYSTEMS, LTD.. The applicant listed for this patent is HITACHI AUTOMOTIVE SYSTEMS, LTD.. Invention is credited to Daisuke KATO, Atsushi NAGANUMA, Hideaki OHNISHI.
Application Number | 20200141407 16/629456 |
Document ID | / |
Family ID | 65001664 |
Filed Date | 2020-05-07 |
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United States Patent
Application |
20200141407 |
Kind Code |
A1 |
KATO; Daisuke ; et
al. |
May 7, 2020 |
PUMP
Abstract
The present invention is directed to providing a pump capable of
achieving improvement of a discharge efficiency. A pump configured
to suck and discharge fluid includes a housing, a driving shaft
rotatably supported on the housing, and a pump element contained in
the housing and configured to be rotated by the driving shaft. The
housing contains therein an intake passage into which the fluid
delivered from outside the housing is introduced, an intake port
configured to guide the fluid from the intake passage to the pump
element, a discharge port into which the fluid pressurized by the
pump element is introduced, and a discharge passage configured to
discharge the fluid delivered from the discharge port to outside
the housing. The discharge passage includes a first passage
including a beginning portion connected to the discharge port and a
termination portion. The first passage extends as far as the
termination portion around one straight line. The discharge passage
further includes a second passage connected to the termination
portion of the first passage and opened to outside the housing. A
shape of the first passage in cross section taken along a direction
perpendicular to the straight line changes continuously from the
beginning portion to the termination portion.
Inventors: |
KATO; Daisuke; (Novi,
MI) ; NAGANUMA; Atsushi; (Atsugi-shi, Kanagawa,
JP) ; OHNISHI; Hideaki; (Atsugi-shi, Kanagawa,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HITACHI AUTOMOTIVE SYSTEMS, LTD. |
Hitachinaka-shi, Ibaraki |
|
JP |
|
|
Assignee: |
HITACHI AUTOMOTIVE SYSTEMS,
LTD.
Hitachinaka-shi, Ibaraki
JP
|
Family ID: |
65001664 |
Appl. No.: |
16/629456 |
Filed: |
July 6, 2018 |
PCT Filed: |
July 6, 2018 |
PCT NO: |
PCT/JP2018/025620 |
371 Date: |
January 8, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 2270/185 20130101;
F01C 21/10 20130101; F04C 14/226 20130101; F05C 2201/021 20130101;
F04C 15/06 20130101; F04C 2210/206 20130101; F04C 2/3442 20130101;
F04C 2230/21 20130101; F04C 2240/807 20130101; F04C 15/0057
20130101; F04B 53/16 20130101 |
International
Class: |
F04C 15/06 20060101
F04C015/06; F04C 15/00 20060101 F04C015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2017 |
JP |
2017-135504 |
Claims
1. A pump configured to suck and discharge fluid, the pump
comprising: a housing; a driving shaft rotatably supported on the
housing; and a pump element contained in the housing and configured
to be rotated by the driving shaft, wherein the housing contains
therein an intake passage to which the fluid is introduced from
outside the housing, an intake port configured to guide the fluid
from the intake passage to the pump element, a discharge port to
which the fluid is introduced after being pressurized by the pump
element, and a discharge passage configured to discharge the fluid
delivered from the discharge port to outside the housing, wherein
the discharge passage includes a first passage including a
beginning portion connected to the discharge port and a termination
portion, the first passage extending as far as the termination
portion around one straight line, and a second passage connected to
the termination portion of the first passage, the second passage
being opened to outside the housing, and wherein a shape of the
first passage in cross section taken along a direction
perpendicular to the straight line continuously changes from the
beginning portion to the termination portion.
2. The pump according to claim 1, wherein, a cross-sectional shape
of a connection portion between the discharge port and the
beginning portion changes continuously between the discharge port
and the beginning portion.
3. The pump according to claim 1, wherein the straight line extends
along an axis of the driving shaft.
4. The pump according to claim 1, wherein the housing includes a
housing main body including a recessed portion, the recessed
portion being a bottomed cylindrical recessed portion extending
around an axis of the driving shaft, the recessed portion
containing the pump element, and a cover closing an opening of the
recessed portion, and wherein the discharge port is opened on a
bottom surface of the recessed portion in an axial direction of the
driving shaft.
5. The pump according to claim 4, wherein the discharge port
extends along an axis of the driving shaft.
6. The pump according to claim 1, wherein a dimension of the
discharge port in a rotational direction of the driving shaft is
larger than a dimension of the discharge port in a radial direction
of the driving shaft, and wherein a dimension of the first passage
in the rotational direction of the driving shaft is larger than a
dimension of the first passage in the radial direction of the
driving shaft.
7. The pump according to claim 6, wherein the first passage is
disposed on a front side in the rotational direction of the driving
shaft with respect to the discharge port.
8. The pump according to claim 6, wherein at least a part of a wall
on an outer side in the radial direction of the driving shaft,
among walls forming an inner periphery of the discharge port, is
located on the outer side in the radial direction of the driving
shaft with respect to a circular arc, the circular arc being
centered at the axis of the driving shaft, the circular arc passing
through an end on the outer side in the radial direction of the
driving shaft in the beginning portion of the discharge port in the
rotational direction of the driving shaft.
9. The pump according to claim 1, wherein the housing includes a
plate-like flattened portion, wherein a part of the first passage
and the second passage are located inside the flattened portion,
wherein the second passage is opened on a surface of the flattened
portion on one side, and wherein a fixation portion for fixing a
member connected to an opening of the second passage is provided at
the flattened portion.
10. The pump according to claim 1, wherein the second passage is
opened to outside the housing at a position away from the driving
shaft in the axial direction of the driving shaft.
11. The pump according to claim 1, wherein a second end portion of
the driving shaft on an opposite side from a first end portion of
the driving shaft that is located close to the opening of the
second passage in the axial direction of the driving shaft
protrudes from the housing, and is connected to a member for
driving the driving shaft.
12. The pump according to claim 1, wherein the second passage
extends along one straight line.
13. The pump according to claim 1, wherein an area of the cross
section of the first passage reduces as the first passage extends
from the beginning portion to the termination portion.
14. The pump according to claim 1, wherein the second passage
extends in a direction different from a direction in which the
first passage extends, wherein an area of an opening of the second
passage at the termination portion of the first passage is equal to
or smaller than an area of the first passage in cross section taken
at a portion of the opening of the second passage at the
termination portion of the first passage that is located closest to
the beginning portion of the first passage, and is equal to or
larger than an area of the first passage in cross section taken at
a portion of the opening of the second passage at the termination
portion of the first passage that is located farthest from the
beginning portion of the first passage.
15. The pump according to claim 1, wherein the housing includes a
housing main body including a recessed portion containing the pump
element, a cover closing an opening of the recessed portion, a
first fixation portion for fixing the cover to the housing main
body, and a second fixation portion for fixing the housing to
another member at a different position from the first fixation
portion.
16. A pump configured to pressurize and discharge sucked fluid, the
pump comprising: a housing; a shaft rotatably supported on the
housing; and a pump element contained in the housing and coupled
with the shaft, wherein the housing contains therein an intake
passage for introducing the fluid from outside the housing to the
pump element, and a discharge passage for discharging the fluid
pressurized by the pump element to outside the housing, and wherein
the discharge passage includes a first passage extending around one
straight line and including a beginning portion on one side where
the pump element is located, and a termination portion, the first
passage being shaped in such a manner that an area of a cross
section thereof perpendicular to the straight line gradually
reduces as the first passage extends from the beginning portion
toward the termination portion, and a second passage connected to
the termination portion of the first passage and opened to outside
the housing.
17. The pump according to claim 16, wherein the straight line
extends along an axis of the shaft, and wherein a dimension of the
first passage in a rotational direction of the shaft is larger than
a dimension of the first passage in a radial direction of the
shaft.
18. A method for manufacturing a pump, comprising: forming a
housing main body integrally by casting, the housing main body
including a recessed portion capable of rotationally containing a
pump element, an intake port opened on the recessed portion, a
discharge port opened on the recessed portion and extending along a
rotational axis of the pump element, the discharge port having a
flattened shape elongated in a rotational direction of the pump
element in cross section perpendicular to the rotational axis of
the pump element, a first passage connected to the discharge port
and extending along the rotational axis of the pump element, the
first passage having a flattened shape elongated in the rotational
direction of the pump element in cross section perpendicular to the
rotational axis of the pump element, and a second passage connected
to the first passage and extending linearly to be opened on an
outer surface of the housing; mounting the pump element into the
recessed portion; and closing an opening of the recessed portion
with a cover.
Description
TECHNICAL FIELD
[0001] The present invention relates to a pump.
BACKGROUND ART
[0002] Conventionally, there has been known a pump configured to
suck and discharge fluid. For example, PTL 1 discloses a pump
including a housing, a shaft rotatably supported on the housing,
and a pump element contained in the housing and coupled with the
above-described shaft. An intake passage for introducing the fluid
from outside the housing into the pump element, and a discharge
passage for discharging the fluid pressurized by the pump element
to outside the housing are provided inside the housing of this
pump.
CITATION LIST
Patent Literature
[0003] [PTL 1] Japanese Patent Application Public Disclosure No.
2016-142220
SUMMARY OF INVENTION
Technical Problem
[0004] The conventional pump entails a risk of a reduction in the
discharge efficiency of the pump due to a discontinuous change in
the cross-sectional shape of the discharge passage.
Solution to Problem
[0005] In a pump according to one aspect of the present invention,
a discharge passage includes a first passage and a second passage.
The first passage extends around one straight line. A shape of the
first passage in cross section taken along a direction
perpendicular to this straight line changes continuously from a
beginning portion to a termination portion. The second passage is
connected to the termination portion of the first passage, and is
opened to outside the housing.
[0006] Therefore, the pump can improve the discharge efficiency
thereof.
BRIEF DESCRIPTION OF DRAWINGS
[0007] FIG. 1 illustrates a circuit of a hydraulic oil supply
system of an engine according to a first embodiment.
[0008] FIG. 2 is a perspective view of a balancer module with a
pump according to the first embodiment mounted thereon.
[0009] FIG. 3 is a side view of the balancer module with the pump
according to the first embodiment mounted thereon.
[0010] FIG. 4 illustrates a cross section as viewed along a line
IV-IV in FIG. 3.
[0011] FIG. 5 is a front view of the pump according to the first
embodiment.
[0012] FIG. 6 illustrates a cross section as viewed along a line
VI-VI in FIG. 5.
[0013] FIG. 7 is a perspective view in which the pump according to
the first embodiment is disassembled and each component is lined
along the same axis.
[0014] FIG. 8 is a front view of the pump with a cover removed
therefrom according to the first embodiment.
[0015] FIG. 9 is a front view of a housing main body according to
the first embodiment.
[0016] FIG. 10 illustrates a cross section as viewed along a line
X-X in FIG. 9.
[0017] FIG. 11 is a bottom view of the housing main body according
to the first embodiment.
[0018] FIG. 12 illustrates a discharge port and the vicinity
thereof in the front view of the housing main body according to the
first embodiment in an enlarged manner.
[0019] FIG. 13 illustrates a cross section as viewed along a line
XIII-XIII in FIG. 11.
[0020] FIG. 14 illustrates a cross section as viewed along a line
XIV-XIV in FIG. 11.
[0021] FIG. 15 illustrates a cross section as viewed along a line
XV-XV in FIG. 11.
[0022] FIG. 16 illustrates a cross section as viewed along a line
XVI-XVI in FIG. 9.
[0023] FIG. 17 is a schematic view of a discharge passage according
to the first embodiment, and indicates a flow of oil with
arrows.
[0024] FIG. 18 is a schematic view of the discharge passage
according to another embodiment, and indicates the flow of the oil
with arrows.
[0025] FIG. 19 is a front view of the pump according to a second
embodiment.
[0026] FIG. 20 illustrates a cross section as viewed along a line
XX-XX in FIG. 19.
[0027] FIG. 21 illustrates a cross section as viewed along a line
XXI-XXI in FIG. 19.
DESCRIPTION OF EMBODIMENTS
[0028] In the following description, embodiments for implementing
the present invention will be described with reference to the
drawings.
First Embodiment
[0029] First, a configuration will be described. A pump 1 according
to the present embodiment is used for a hydraulic oil supply system
of an internal combustion engine (an engine) of an automobile. The
engine is a reciprocating engine, and is an in-line multi-cylinder
(for example, four-cylinder) engine. The pump 1 is an oil pump that
supplies oil (hydraulic oil) in the form of fluid to each sliding
portion and a variable actuation valve mechanism of the engine. The
variable actuation valve mechanism is a valve timing controller or
the like, and controls an actuation characteristic of a valve in
the engine. The pump 1 is a source that generates a hydraulic
pressure for lubrication and actuation of the variable actuation
valve mechanism. As illustrated in FIG. 1, the hydraulic oil supply
system of the engine includes an oil pan 100, oil passages, the
pump 1, a pressure sensor 18, and a control mechanism. The oil pan
100 is located at a lower portion of the engine, and is a
low-pressure portion in which the hydraulic oil is stored. The
passages include an intake passage 11, a discharge passage 12, a
relief passage 13, and a main gallery 14. One end of the intake
passage 11 is connected to the oil pan 100 via an oil strainer 101.
The other end of the intake passage 11 is connected to an intake
port 110 of the pump 1. One end of the discharge passage 12 is
connected to a discharge port 120 of the pump 1. The other end of
the discharge passage 12 is connected to an oil filter 102. The
relief passage 13 branches off from the discharge passage 12, and
can discharge the hydraulic oil to the oil pan 100. A relief valve
16 is mounted in the relief passage 13. One end of the main gallery
14 is connected to the oil filter 102. The main gallery 14 can
supply the hydraulic oil to each sliding portion of the engine, the
variable actuation valve device, and the like. The pressure sensor
18 is mounted in the main gallery 14. The pressure sensor 18
detects a pressure (a main gallery pressure) P1 in the main gallery
14.
[0030] The control mechanism includes a control passage 15, a
control valve 17, and an engine control unit 19. The control valve
17 is an electromagnetic valve (a solenoid valve) including a valve
portion and a solenoid portion, and is a proportional control
valve. The valve portion is a three-way valve. The valve portion is
a spool valve, and includes a housing, a spool as a valve body, and
a spring as a return spring. The housing includes an inlet port
171, a pilot port 172, a discharge port 173, and an outlet port
174. The spring biases the spool toward an initial position. A
pressure (a pilot pressure) of the oil supplied from the pilot port
172 to inside the housing biases the spool in a direction opposite
from the spring. The solenoid portion generates an electromagnetic
force, and biases the spool in the direction opposite from the
spring. The solenoid portion can continuously change strength of
the electromagnetic force according to a value of a supplied
current. The control passage 15 includes a supply passage 151, a
feedback passage 152, a discharge passage 153, and a communication
passage 154. The supply passage 151 branches off from the main
gallery 14, and is connected to the inlet port 171 of the control
valve 17. The feedback passage 152 branches off from the supply
passage 151, and is connected to the pilot port 172 of the control
valve 17. The discharge passage 153 is connected to the discharge
port 173 of the control valve 17, and is in communication with the
oil pan 100. The communication passage 154 connects the output port
174 of the control valve 17 and a control chamber 80 of the pump 1
to each other.
[0031] As illustrated in FIGS. 2 to 4, the pump 1 is mounted in a
balancer module (a balancer unit) 2 of the engine. In other words,
the balancer module 2 is a pump-integrated balancer. The balancer
module 2 is a balancer mechanism for canceling out a secondary
vibration generated at the engine, and generates a vibratory force
in a direction for canceling out the above-described vibration by
balancer shafts 25 and 26 rotating in synchronization with a
crankshaft. The module 2 includes a housing, the balancer shafts 25
and 26, and a gear. The housing includes a lower housing 200 and an
upper housing 201. In the following description, a
three-dimensional orthogonal coordinate system is set in the
drawings for the sake of the description. A z-axis is set to a
direction in which axes of the balancer shafts 25 and 26 extend,
and a positive side thereof is defined to be the pump 1 side with
respect to the balancer shafts 25 and 26. An x-axis is set to a
horizontal direction perpendicular to the z-axis, and a positive
side thereof is defined to be the driving-side shaft 25 side with
respect to the driven-side shaft 26. A y-axis is set to a vertical
direction (an upright direction) perpendicular to the z-axis, and a
positive side thereof is defined to be the upper housing 201 side
with respect to the lower housing 200. The z-axis direction extends
horizontally and the y-axis direction extends vertically with the
engine mounted on the vehicle (the automobile). The y-axis positive
direction is located on a vertically upper side, and the x-axis
negative direction is located on a front side of the vehicle. The
layout of the engine on the vehicle is not limited thereto.
[0032] As illustrated in FIG. 4, the lower housing 200 includes
gear containing portions, bearing containing portions, and weight
containing portions. Each of the containing portions has a
semi-cylindrical shape extending in the z-axis direction, and is
opened on a surface of the lower housing 200 on the y-axis positive
direction side. The gear containing portions include a driving gear
containing portion 211, a driving-side inverting gear containing
portion 212, a driven-side inverting gear containing portion 213, a
reducing gear containing portion 214, and a pump driving gear
containing portion 215. The bearing containing portions include a
driving-side first bearing containing portion 221, a driving-side
second bearing containing portion 222, a driven-side first bearing
containing portion 223, and a driven-side second bearing containing
portion 224. The weight containing portions include a driving-side
weight containing portion 231 and a driven-side weight containing
portion 232. The driving gear containing portion 211, the
driving-side first bearing containing portion 221, the driving-side
weight containing portion 231, the driving-side second bearing
containing portion 222, and the driving-side inverting gear
containing portion 212 are arranged in this order from the z-axis
positive direction side toward the z-axis negative direction side
on one axis of the lower housing 200 on the x-axis positive
direction side. The reducing gear containing portion 214, the
driven-side first bearing containing portion 223, the driven-side
weight containing portion 232, the driven-side second bearing
containing portion 224, and the driven-side inverting gear
containing portion 213 are arranged in this order from the z-axis
positive direction side toward the z-axis negative direction side
on one axis of the lower housing 200 on the x-axis negative
direction side. The pump driving gear containing portion 215 is
located adjacent to the driving gear containing portion 211 on the
z-axis positive direction side at an end of the lower housing 200
in the z-axis positive direction and a center of the lower housing
200 in the x-axis direction. The pump driving gear containing
portion 215 and the reducing gear containing portion 214, the
driving-side first bearing containing portion 221 and the
driven-side first bearing containing portion 223, the driving-side
weight containing portion 231 and the driven-side weight containing
portion 232, the driving-side second bearing containing portion 222
and the driven-side second bearing containing portion 224, and the
driving-side inverting gear containing portion 212 and the
driven-side inverting gear containing portion 213 are located
adjacent to each other in the x-axis direction, respectively. A
bolt hole 241 penetrating through the lower housing 200 in the
y-axis direction is located adjacent to each of the bearing
containing portions in the x-axis direction.
[0033] The upper housing 201 includes gear containing portions,
bearing containing portions, weight containing portions, and a
mounting portion 242. Each of the containing portions is shaped and
laid out substantially identically to the corresponding containing
portion in the lower housing 200, and is opened to a surface of the
upper housing 201 on the y-axis negative direction side. The
driving gear containing portion 211 is also opened on a surface of
the upper housing 201 on the y-axis positive direction side. The
upper housing 201 is fixed to the lower housing 200 with use of a
bolt 202 penetrating through the bolt hole 241 of the lower housing
200. A surface of the lower housing 200 on the y-axis positive
direction side and the surface of the upper housing 201 on the
y-axis negative direction side are joined to each other, by which
the gear containing portions, the bearing containing portions, and
the weight containing portions are completed. The mounting portion
242 is a protrusion portion protruding from the surface of the
upper housing 201 on the y-axis positive direction side, and
includes a bolt hole extending in the y-axis direction. The
balancer module 2 is mounted on a lower portion (a y-axis negative
direction side) of the cylinder block so as to hang down with use
of a bolt 203 penetrating through the bolt hole of the mounting
portion 242. The balancer module 2 is contained in the oil pan
100.
[0034] The balancer shafts include the driving-side shaft 25 and
the driven-side shaft 26. The driving-side shaft 25 and the
driven-side shaft 26 are disposed in parallel with the crankshaft.
Both the shafts 25 and 26 are sandwiched between the upper housing
201 and the lower housing 200, are arranged adjacent to each other
in an xz plane, and are rotatably supported on both the housings
200 and 201. These shafts 25 and 26 include balancer weights 250
and 260, respectively. The weights 250 and 260 are each an
eccentric weight having a center of gravity offset from the axes of
these shafts 25 and 26. The gears include a balancer driving gear
27, inverting gears, and a reducing gear 29. The inverting gears
include a driving-side inverting gear 281 and a driven-side
inverting gear 282. The balancer driving gear 27 is fixed to an end
of the driving-side shaft 25 in the z-axis positive direction. The
driving-side inverting gear 281 is fixed to an end of the
driving-side shaft 25 in the z-axis negative direction. The
driven-side inverting gear 282 is fixed to an end of the
driven-side shaft 26 in the z-axis negative direction. The reducing
gear 29 is fixed to an end of the driven-side shaft 26 in the
z-axis positive direction. They are fixed by press-fitting or the
like.
[0035] The balancer weight 250 of the driving-side shaft 25 is
contained in the driving-side weight containing portion 231 of both
the housings 200 and 201. The balancer driving gear 27 is contained
in the driving gear containing portion 211 of both the housings 200
and 201. The driving-side inverting gear 281 is contained in the
driving-side inverting gear containing portion 212 of both the
housings 200 and 201. A journal portion of the driving-side shaft
25 between the balancer weight 250 and the balancer driving gear 27
is supported by a bearing 251 contained in the driving-side first
bearing containing portion 221 of both the housings 200 and 201. A
journal portion between the balancer weight 250 and the
driving-side inverting gear 281 is supported by a bearing 252
contained in the driving-side second bearing containing portion 222
of both the housings 200 and 201. The balancer weight 260 of the
driven-side shaft 26 is contained in the driven-side weight
containing portion 232 of both the housings 200 and 201. The
reducing gear 29 is contained in the reducing gear containing
portion 214 of both the housings 200 and 201. The driven-side
inverting gear 282 is contained in the driven-side inverting gear
containing portion 213 of both the housings 200 and 201. A journal
portion of the driven-side shaft 26 between the balancer weight 260
and the reducing gear 29 is supported by a bearing 261 contained in
the driven-side first bearing containing portion 223 of both the
housings 200 and 201. A journal portion between the balancer weight
260 and the driven-side inverting gear 282 is supported by a
bearing 262 contained in the driven-side second bearing containing
portion 224 of both the housings 200 and 201. A part of an outer
periphery of the balancer driving gear 27 protrudes from an opening
portion of the upper housing 201 toward the y-axis positive
direction side, and is meshed with a gear integrated with the
crankshaft. A gear ratio of the balancer driving gear 27 is set in
such a manner that the driving-side shaft 25 rotates twice as fast
as the number of rotations of the crankshaft. The driven-side
inverting gear 282 is meshed with the driving-side inverting gear
281. Both the shafts 25 and 26 rotate in opposite directions from
each other at the same number of rotations.
[0036] As illustrated in FIGS. 5 to 8, the pump 1 is a variable
displacement-type vane pump. The pump 1 includes a housing 3, bolts
30, a pump driving gear 400, a driving shaft 4, a rotor 5, a
plurality of vanes 6, vane rings 61 and 62, a cam ring 7, a seal
member 71, a pin 72, and a spring 73. The housing 3 includes a
housing main body (a body) 300 and a cover 301.
[0037] As illustrated in FIGS. 9 to 11, the housing main body 300
includes a pump element containing portion 31, a spring containing
portion 32, passage portions, and a flange portion 35. A bearing
portion 360, a pin hole 361, a pump element containing hole 362, a
spring containing hole 363, an intake port 110, a discharge port
120, an intake passage 11, a discharge passage 12, and a
communication passage 154 are provided inside the housing main body
300. The pump element containing portion 31 has a bottomed
cylindrical shape, and includes a bottom portion 310 and a
cylindrical circumferential wall 311. The pump element containing
hole 362, the bearing portion 360, the pin hole 361, the intake
port 110, and the discharge port 120 are provided in the pump
element containing portion 31. The pump element containing hole 362
is a bottomed cylindrical recessed portion extending in the z-axis
direction. The hole 362 is closed on the z-axis positive direction
side by the bottom portion 310, and is opened on the z-axis
negative direction side on a surface of the housing main body 300
on the z-axis negative direction side. The bearing portion 360
extends around an axis 40 in the z-axis direction, and penetrates
through a generally central position of the bottom portion 310. The
pump element containing hole 362 extends around the axis 40. The
pin hole 361 has a bottomed cylindrical shape extending in the
z-axis direction, and is opened on the surface of the bottom
portion 310 on the z-axis negative direction side (a bottom surface
364 of the pump element containing hole 362 in the z-axis
direction). The pin hole 361 is located an outer edge of the bottom
surface 364 on the x-axis positive direction side and the y-axis
positive direction side. The intake port 110 and the discharge port
120 are arcuate recessed portions extending in the direction around
the axis 40 (hereinafter referred to as a circumferential
direction), and are opened on the surface of the bottom portion 310
on the z-axis negative direction side (the bottom surface 364 of
the pump element containing hole 362). The intake port 110 is
bottomed. The intake port 110 is located between the bearing
portion 360 and the pin hole 361 on the bottom surface 364. The
discharge port 120 is located on the pin hole 361 side with respect
to the bearing portion 360. A straight line passing through the
axis 40 and the pin hole 361 (a central axis thereof) overlap both
the ports 110 and 120. These ports 110 and 120 are located on
opposite sides of a straight line extending perpendicular to this
straight line and passing through the axis 40 from each other.
[0038] As illustrated in FIGS. 10 and 12, the discharge port 120
extends around a first straight line 91 inside the bottom portion
310. The first straight line 91 extends in parallel with the axis
40, and extends along the axis 40 (in the z-axis direction). The
first straight line 91 passes through a circumferentially
intermediate position of the opening of the discharge port 120 on
the bottom surface 364. A cross section of the discharge port 120
taken along a direction perpendicular to the first straight line 91
has a circumferentially elongated flattened shape. A dimension of
the discharge port 120 in the circumferential direction is larger
than a dimension of the discharge port 120 in a radial direction of
the driving shaft 4. A wall 121 on a rotational direction side of
the driving shaft 4, among walls forming an inner periphery of the
discharge port 120, extends along the radial direction of the
driving shaft 4 and is also slightly inclined with respect to the
first straight line 91, and is gradually displaced toward an
opposite rotational direction side of the driving shaft 4 as
extending from the negative direction side toward the positive
direction side of the z-axis. A wall 122 on the opposite rotational
direction side of the driving shaft 4 extends along the radial
direction of the driving shaft 4 and is also inclined with respect
to the first straight line 91, and is gradually displaced toward
the rotational direction side of the driving shaft 4 as extending
from the negative direction side toward the positive direction side
of the z-axis. A wall 123 on an inner side in the radial direction
of the driving shaft 4 extends along the circumferential direction
and is also slightly inclined with respect to the first straight
line 91, and is gradually displaced toward an outer side in the
radial direction as extending from the negative direction side
toward the positive direction side of the z-axis. A wall on the
outer side in the radial direction includes a portion 124 bulging
inward in the radial direction near the pin hole 361. A portion 125
of the wall on the outer side in the radial direction on the
opposite rotational direction side of the driving shaft 4 with
respect to the above-described bulging portion 124 extends along
the circumferential direction. A portion 126 on the rotational
direction side of the driving shaft 4 with respect to the
above-described bulging portion 124 has a so-called pent roof-like
shape, and includes a portion slightly bulging outward in the
radial direction with respect to a circular arc .gamma.. The
circular arc .gamma. is a circular arc centered at the axis 40, and
passing through an end on the outer side in the radial direction
that is one of beginning portions of the discharge port 120 (in the
circumferential direction). Further, the walls 124, 125, and 126 on
the outer side in the radial direction are slightly inclined with
respect to the first straight line 91, and are gradually displaced
inward in the radial direction as extending from the negative
direction side toward the positive direction side of the
z-axis.
[0039] As illustrated in FIG. 9, the spring containing portion 32
is located on a y-axis negative direction side of the pump element
containing portion 31. The spring containing portion 32 includes
the intake passage 11 and the spring containing hole 363. The
intake passage 11 and the spring containing hole 363 are opened on
the surface of the housing 300 on the z-axis negative direction
side. The intake passage 11 is opened on the circumferential wall
311 of the pump element containing hole 362, and is connected to
the intake port 110. The intake passage 11 extends from the intake
port 110 toward the x-axis negative direction side and the y-axis
negative direction side. The spring containing hole 363 has a
cylindrical shape extending generally along the x-axis direction,
and intersects with the intake passage 11.
[0040] The passage portions include a discharge passage portion 33
and a communication passage portion 34. As illustrated in FIGS. 10
and 11, the discharge passage portion 33 extends in the x-axis
positive direction from a y-axis positive direction side of a
surface of the pump element containing portion 31 (the bottom
portion 310) on the z-axis positive direction side. The discharge
passage portion 33 includes a main body portion 330, a first
bulging portion 331, and a second bulging portion 332. The
discharge passage portion 33 is a plate-like flattened portion
extending along the xz plane. Dimensions of the main body portion
330 in the x-axis direction and the z-axis direction are larger
than a dimension of the main body portion 330 in the y-axis
direction. Bolt holes 333 are provided at the bulging portions 331
and 332. The bolt holes 333 extend in the y-axis direction and
penetrate through the bulging portions 331 and 332. The first
bulging portion 331 overlaps the main body portion 330 on an x-axis
negative direction side and a z-axis negative direction side of the
discharge passage portion 33, and is connected to the bottom
portion 310. The second bulging portion 332 overlaps the main body
portion 330 on an x-axis positive direction side and a z-axis
positive direction side of the discharge passage portion 33, and is
connected to a z-axis positive direction side of the bottom portion
330. An x-axis positive direction side of the discharge passage
portion 33 extends in the z-axis direction. As viewed from the
y-axis direction, an x-axis negative direction side of the
discharge passage portion 33 has such a shape that a large circular
arc of the main body portion 330 is sandwiched by small circular
arcs of the bulging portions 331 and 332, and extends while being
inclined with respect to the x-axis and the z-axis. A surface of
the discharge passage portion 33 on the y-axis negative direction
side is in parallel with the xz plane. A surface of the discharge
passage portion 33 on the y-axis positive direction side is
slightly inclined with respect to the xz plane, and is gradually
displaced toward the y-axis negative direction side as extending
from the negative direction side toward the positive direction side
of the z-axis.
[0041] The discharge passage 12 includes a first passage 12A and a
second passage 12B. Both the passages 12A and 12B are located
inside the main body portion 330. As illustrated in FIGS. 12 to 16,
the first passage 12A has a beginning portion 12A1 connected to the
discharge port 120, and extends as far as a termination portion
12A2 around a second straight line 92. The second straight line 92
is in parallel with the axis 40 of the driving shaft 4, and extends
along the axis 40 (in the z-axis direction). The second straight
line 92 passes through a circumferentially intermediate position of
the first passage 12A. A cross section of the first passage 12A
taken along a direction perpendicular to the second straight line
92 has a flattened shape elongated in the circumferential
direction. A dimension of the first passage 12A in the
circumferential direction is larger than a dimension of the first
passage 12A in the radial direction of the driving shaft 4. The
first passage 12A (the second straight line 92) is eccentric toward
the rotational direction side of the driving shaft 4 with respect
to the discharge port 120 (the first straight line 91). A wall 127
on the rotational direction side of the driving shaft 4, among
walls forming an inner periphery of the first passage 12A, extends
along the y-axis direction and is also slightly inclined with
respect to the first straight line 91, and is gradually displaced
toward the opposite rotational direction side of the driving shaft
4 as extending from the negative direction side toward the positive
direction side of the z-axis. A curved surface portion 127A is
provided on a z-axis negative direction side of the wall 127, and
this curved surface portion 127A is smoothly continuously connected
to the wall 121 of the discharge port 120. A wall 128 on the
opposite rotational direction side of the driving shaft 4 has a
curved surface-like shape convexed toward the opposite rotational
direction of the driving shaft 4, and is also smoothly (via a
curved surface) continuously connected to the wall 122 of the
discharge port 120 on the opposite rotational direction side of the
driving shaft 4. The surface 128 is slightly inclined with respect
to the first straight line 91, and is gradually displaced toward
the rotational direction side of the driving shaft 4 (the x-axis
positive direction side) as extending from the negative direction
side toward the positive direction side of the z-axis. A wall on
the inner side in the radial direction of the driving shaft 4
extends along the circumferential direction, and an end portion
123A thereof on the opposite rotational direction side of the
driving shaft 4 also partially extends in the x-axis direction. The
end portion 123A is continuously connected to the wall 122 of the
discharge port 120 smoothly (via a curved surface). The other
portion forms the same plane as the wall 123 of the discharge port
120 on the inner side in the radial direction of the driving shaft
4. The walls 123 and 123A on the inner side in the radial direction
of the driving shaft 4 are slightly inclined with respect to the
first straight line 91, and are gradually displaced outward in the
radial direction as extending from the negative direction side
toward the positive direction side of the z-axis. The wall on the
outer side in the radial direction of the driving shaft 4 forms the
same plane as the walls 124 and 126 of the discharge port 120 on
the outer side in the radial direction of the driving shaft 4. The
end portion (the beginning portion) 124 of the radially outer wall
on the opposite rotational direction side of the driving shaft 4
bulges inward in the radial direction near the pin hole 361. A
portion 126 not including this bulging portion 124 has a so-called
pent roof-like shape, and includes a portion slightly bulging
outward in the radial direction with respect to the above-described
circular arc .gamma.. Further, the walls 124 and 125 on the outer
side in the radial direction are slightly inclined with respect to
the first straight line 91, and are gradually displaced inward in
the radial direction as extending from the negative direction side
toward the positive direction side of the z-axis. A wall 129 at an
end in the z-axis positive direction extends perpendicularly to the
z-axis. Each of the portions 127, 128, and 129, and the like of the
wall forming the inner periphery of the first passage 12A is
continuously connected to each other smoothly (via a curved
surface).
[0042] In this manner, the shape of the first passage 12A in cross
section taken along the direction perpendicular to the second
straight line 92 changes continuously from the beginning portion
12A1 to the termination portion 12A2 of the first passage 12A. The
shape of a connection portion between the beginning portion 12A1
and the discharge port 120 in cross section perpendicular to the
axis 40 changes continuously between the beginning portion 12A1 and
the discharge port 120. The cross-sectional area of this connection
portion gradually reduces as the connection portion extends from
the discharge port 120 toward the beginning portion 12A1 (as the
connection portion extends from the negative direction side to the
positive direction side along the z-axis). The cross-sectional area
of the first passage 12A gradually reduces as the first passage 12A
extends from the beginning portion 12A1 toward the termination
portion 12A2 (as the first passage 12A extends from the negative
direction side to the positive direction side along the
z-axis).
[0043] The second passage 12B is connected to the termination
portion 12A2 of the first passage 12A, and extends around a third
straight line 93 (along a third straight line 93) to be opened to
outside the housing 3. The third straight line 93 extends in the
y-axis direction. The second passage 12B is opened on the surface
of the main body portion 330 on the y-axis negative direction side.
This opening is located at a position away from the bottom portion
310 (the end of the driving shaft 4 in the z-axis positive
direction) by a predetermined distance in the axial direction of
the driving shaft 4 (the z-axis direction). A cross section of the
second passage 12B taken along a direction perpendicular to the
third straight line 93, including the above-described opening, is
circular. The area of the opening of the second passage 12B at the
termination portion 12A2 of the first passage 12A is equal to or
smaller than a cross-sectional area of the first passage 12A taken
at a portion .alpha. of this opening that is closest to the
beginning portion 12A1 (the end in the z-axis negative direction,
refer to FIG. 11), and is equal to or larger than a cross-sectional
area of the first passage 12A taken at a farthest portion .beta. of
the above-described opening from the beginning portion 12A1 (the
end in the z-axis positive direction). A member such as a pipe and
the oil filter 102 is connected to the opening of the second
passage 12B that is opened to outside the housing 3. Bolts
penetrate through the bolt holes 333 of both the bulging portions
331 and 332. The bulging portions 331 and 332 function as fixation
portions for fixing the member connected to the above-described
opening of the second passage 12B together with the above-described
bolts.
[0044] As illustrated in FIGS. 9 and 11, the communication passage
portion 34 extends in the x-axis positive direction from an outer
surface of the pump element containing portion (the circumferential
wall 311) on the x-axis positive direction side and the y-axis
positive direction side. The communication passage portion 34
includes a main body portion 340 and boss portions 341 and 342.
Bolt holes 343 are provided at the boss portions 341 and 342. The
bolt holes 343 extend in the y-axis direction, and penetrate
through the boss portions 341 and 342. The communication passage
154 is provided inside the communication passage portion 34. A
beginning portion of the communication passage 154 is opened on a
surface on the y-axis negative direction side at an end portion of
the main body portion 340 on the x-axis positive direction side. A
member connected to the control valve 17 is connected to the
opening of the communication passage 154. The boss portions 341 and
342 function as fixation portions for fixing the above-described
member connected to the control valve 17. A termination portion of
the communication passage 154 is opened on an inner peripheral
surface of the pump element containing hole 362.
[0045] As illustrated in FIG. 9, the flange portion 35 is located
on the z-axis negative direction side of the housing main body 300,
and surrounds the openings of the pump element containing hole 362
and the intake passage 11 (the spring containing hole 363). Three
first boss portions 351, three second boss portions 352, and one
pin hole 354 are provided at the flange portion 35. A bolt hole 353
is provided at each of the boss portions 351 and 352. The bolt hole
353 extends in the z-axis direction and penetrates through the boss
portion 351 or 352. The pin hole 354 extends in the z-axis
direction and penetrates through the flange portion 35. The three
first boss portions 351 are arranged around the pump containing
hole 362 in such a manner that the axis 40 of the driving shaft 4
is interposed between them in the x-axis direction and is also
interposed between them in the y-axis direction on a y-axis
positive direction side of the flange portion 35. The three second
boss portions 352 are arranged around the spring containing hole
363 in such a manner that the axis 40 is interposed between them in
the x-axis direction on a y-axis negative direction side of the
flange portion 35.
[0046] As illustrated in FIG. 7, the cover 301 includes an intake
passage portion 37, an oil strainer mounting portion 38, a relief
passage portion 39, and the flange portion 35. The bearing portion
360, the pin hole 361, the intake port 110, the discharge port
corresponding groove 365, the intake passage 11, and the relief
passage 13 are provided inside the cover 301. The bearing portion
360, the pin hole 361, the intake port 110, the discharge port
corresponding groove 365, and the intake passage 11 are opened on a
surface of the cover 301 on the z-axis positive direction side
while being positioned and shaped in correspondence with the
bearing portion 360, the pin hole 361, the intake port 110, the
discharge port 120, and the intake passage 11 of the housing main
body 300 in the z-axis direction, respectively. The bearing portion
360 penetrates through the cover 301 in the z-axis direction. The
pin hole 361 has a bottomed cylindrical shape extending in the
z-axis direction. The intake port 110 and the discharge port
corresponding groove 365 are bottomed recessed portions. The intake
passage 11 is located inside the intake passage portion 37. One end
of the intake passage 11 is connected to the intake port 110. The
other end side of the intake passage 11 extends in the z-axis
direction and is connected to the oil strainer mounting portion 38.
The oil strainer 101 is mounted in the oil strainer mounting
portion 38. The relief passage portion 39 extends in the x-axis
negative direction and the y-axis negative direction from the outer
surface of the cover 301 on the x-axis negative direction side and
the y-axis positive direction side. The relief passage 13 is
located inside the relief passage portion 39. A beginning portion
of the relief passage 13 is opened on an inner peripheral surface
of the discharge port corresponding groove 365. A termination
portion of the relief passage 13 is opened on the outer surface of
the cover 301. The relief valve 16 is mounted in the relief passage
13. The relief valve 16 includes a ball 160 as a valve body, a
spring 161 as a return spring, and a retainer 162 of the spring
161. The flange portion 35 is located on a z-axis positive
direction side of the cover 301. The boss portions 351 and 352, and
the pin hole 354 are provided on the flange portion 35 at positions
corresponding to the boss portions 351 and 352 and the pin hole 354
of the housing main body 300 in the z-axis direction, respectively.
Another boss portion 352 is provided at the relief passage portion
39. Bolt holes 353 are provided at the boss portions 351 and 352.
Further, another pin hole 355 is provided at the flange portion 35.
The bolt holes 353 extend in the z-axis direction and penetrate
through the boss portions 351 and 352. The pin hole 355 extends in
the z-axis direction and penetrates through the flange portion
35.
[0047] As illustrated in FIGS. 6 and 8, the rotor 5, the plurality
of vanes 6, the vane rings 61 and 62, the cam ring 7, the seal
member 71, and the pin 72 are mounted in the pump element
containing hole 362. The spring 73 is mounted in the spring
containing hole 363. The z-axis positive direction side of the
driving shaft 4 is fitted to the bearing portion 360 of the housing
main body 300, and is rotatably supported. The z-axis negative
direction side of the driving shaft 4 is fitted to the bearing
portion 360 of the cover 301, and is rotatably supported. An
intermediate portion of the driving shaft 4 in the z-axis direction
is located in the pump element containing hole 362. Pluralities of
grooves 41 and protrusion portions 42 extending along the axial
direction of the driving shaft 4 are provided on an outer periphery
of the intermediate portion of the driving shaft 4. A flange
portion 43 is provided at the end of the driving shaft 4 in the
z-axis positive direction. The flange portion 43 can restrict a
movement of the driving shaft 4 relative to the housing main body
300 toward the z-axis negative direction side. The end portion of
the driving shaft 4 in the z-axis negative direction protrudes from
the cover 301 toward the z-axis negative direction side. The pump
driving gear 400 is fixed at this end portion by press-fitting or
the like. The pump driving gear 400 is meshed with the reducing
gear 29 of the balancer module 2. The rotor 5 is columnar.
Pluralities of grooves 51 and protrusion portions 52 extending
along the axis of the rotor 5 are provided on an inner periphery of
the rotor 5. The protrusion portions 42 (the grooves 41) of the
driving shaft 4 are fitted to the grooves 51 (the protrusion
portions 52) of the rotor 5. In other words, the driving shaft 4
and the rotor 5 are coupled axially relatively movably due to
splines. Recessed portions 53 are provided on both sides of the
rotor 5 in the z-axis direction. The vane rings 61 and 62 are
mounted in the recessed portions 53. A plurality of (seven)
radially extending slits 54 is provided inside the rotor 5.
Radially outer sides of the slits 54 are opened on an outer
peripheral surface 50 of the rotor 5. Back-pressure chambers 55 are
connected to radially inner sides of the slits 54. The
back-pressure chambers 55 are cylindrical, and extend in the z-axis
direction and penetrate through the rotor 5. The vanes 6 are
contained in the slits 54. A proximal end of each of the vanes 6
faces the vane ring 61 or 62.
[0048] Both ends of the pin 72 are fitted to the pin hole 361 of
the housing main body 300 and the pin hole 361 of the cover 301,
respectively. An inner peripheral surface 700 of the cylinder 7 is
cylindrical. A pin groove 74, a seal groove 75, and an arm portion
76 are provided on an outer periphery of the cam ring 7. The pin
groove 74 is semi-cylindrical, and extends in the z-axis direction
and penetrates through the cam ring 7. A part of the outer
periphery of the pin 72 is fitted in the pin groove 74. The seal
member 71 is mounted in the seal groove 75. The arm portion 76 is a
plate-like portion, and protrudes from the outer periphery of the
cam ring 7 radially outward. The arm portion 76 is mounted on an
x-axis positive direction side of the spring containing hole 363. A
surface of the arm portion 76 on the x-axis positive direction side
can contact the protrusion 321 located on the x-axis positive
direction side of the spring containing hole 363. A plurality of
grooves 77 is provided on both surfaces of the cam ring 7 in the
z-axis direction. Each of the grooves 77 is shaped generally
identically to the intake port 110 or the discharge port 120 (the
discharge port corresponding groove 365) of the housing 3 that
faces it in the z-axis direction, and is connected to the inner
peripheral side of the cam ring 7. The grooves 77 have a function
of adjusting a force derived from a pressure applied to the cam
ring 7 from the both sides in the z-axis direction. The spring 73
is a compression coil spring. One end of the spring 73 is set on a
surface of the arm portion 76 on the x-axis negative direction
side. The other end of the spring 73 is set on an inner peripheral
surface of the spring containing hole 363 on the x-axis negative
direction side. An axis of the spring 73 is approximately
perpendicular to a straight line connecting an axis of the pin 72
and the surface of the protrusion 321 on the x-axis negative
direction side in an xy plane. The spring 73 is kept in a
compressed state and has a predetermined set load in an initial
state where the cam ring 7 is not actuated (does not swing),
thereby constantly biasing the arm portion 76 toward the x-axis
positive direction side.
[0049] The control chamber 80 is located between the inner surface
of the housing 3 and the outer periphery of the cam ring 7. The
control chamber 80 is a space surrounded by a portion of the outer
peripheral surface 701 of the cam ring 7 between the seal member 71
and the pin 72 (one side not including the arm portion 76), the
inner surface of the pump element containing hole 362, and the
surface of the cover 301 on the z-axis positive direction side. The
control chamber 80 is sealed by the seal member 71 and the pin 72.
The communication passage 154 is opened to the control chamber
80.
[0050] Pump chambers (vane chambers) 81 are separated and formed
(defined) by the outer peripheral surface 50 of the rotor 5, the
two vanes 6 adjacent to each other, the inner peripheral surface
700 of the cam ring 7, the bottom surface 364 of the pump
containing chamber 362, and the surface of the cover 301 on the
z-axis positive direction side. When the rotor 5 rotates, the vanes
6 project from and retract into the outer peripheral surface 50 of
the rotor 5 in such a manner that distal ends of the vanes 6
contact the inner peripheral surface 700 of the cam ring 7. The
volumes of the vane chambers 81 can change according to the
rotation of the rotor 5, and a pump function is exerted with the
aid of increases and reductions in the volumes of the vane chambers
81 according to the rotation. The intake port 110 is opened to the
vane chambers 81 in a range where the volumes of the vane chambers
81 increase (according to the rotation of the rotor 5) (an intake
region). The vane chambers 81 in the intake region suck the oil
from the intake port 110. The discharge port 120 is opened to the
vane chambers 81 in a range where the volumes of the vane chambers
81 reduce (according to the rotation of the rotor 5) (a discharge
region). The vane chambers 81 in the discharge region discharge the
oil to the discharge port 120. The rotation of the crankshaft is
transmitted to the balancer shafts 25 and 26 via the gear 27 and
the like. The rotations of the balancer shafts 25 and 26 are
transmitted to the driving shaft 4 of the pump 1 via the gears 29
and 40. The gear ratios of the gears 29 and 40 are set in such a
manner that the driving shaft 4 rotates half as fast as the number
of rotations of the driven-side shaft 26. As a result, the number
of rotations of the driving shaft 4 matches the crankshaft.
[0051] The driving shaft 4 rotates the rotor 5 in a
counterclockwise direction in FIG. 8. The components forming the
pump chamber such as the rotor 5 and the vanes 6 (pump elements)
pressurize the oil introduced from the intake port 110 and
introduce it to the discharge port 120 by rotating. The axis 40 of
the driving shaft 4 coincides with rotational axes of the pump
elements. The direction around the axis 40 is the rotational
direction of the driving shaft 4, i.e., rotational directions of
the pump elements. A pressure at the discharge port 120 is
introduced into the back-pressure chambers 55. As a result, the
vanes 6 are pushed out from the slits 54. Even when the number of
rotations is low and the centrifugal force and the pressures in the
back-pressure chambers 55 are low, the vane rings 61 and 62 push
out the vanes 6 from the slits 54. Due to this configuration, the
liquid tightness of the vane chambers 81 is improved. Further, a
stress, like a stress that would be generated when the driving
shaft 4 is press-fitted in the rotor 5, is not generated on the
rotor 5 because of the spline fitting between the driving shaft 4
and the rotor 5. Therefore, the pump 1 can prevent such a situation
that the rotor 5 is broken due to the slits 54 spread out by the
hydraulic pressures that the vanes 6 receive when the rotor 5
rotates. The pump 1 sucks the oil from the oil pan 100 via the
intake passage 11 and discharges the oil to the discharge passage
12. The pump 1 pressure-feeds the hydraulic oil to each portion of
the engine via the main gallery 14 connected to the discharge
passage 12. The relief valve 16 is opened and discharges the oil
from the discharge passage 12 via the relief passage 13, when a
pressure in the discharge passage 12 (a discharge pressure) reaches
a predetermined high pressure.
[0052] A theoretical discharge amount (a discharge amount per
rotation), i.e., a capacity of the pump 1 is determined based on a
difference between a maximum volume and a minimum volume of each of
the vane chambers 81. This volume difference (a change amount of
the volume of the vane chamber 81) is changeable. The cam ring 7 is
a member capable of moving (a movable member) inside the pump
containing hole 362, and can swing around the pin 72 in the
rotational direction. The swing of the cam ring 7 causes a change
in the difference between the central axis 40 of the rotor 5 and a
central axis 78 of the cam ring inner peripheral surface 700 (an
eccentricity amount). The change in the eccentricity amount causes
a change in an increase/reduction amount of the volume (the volume
change amount) of each of the plurality of vane chambers 81 when
the rotor 5 rotates. The cam ring 7 is biased by the spring 73
toward one side in a direction of the rotation around the pin 72
(which is the counterclockwise direction in FIG. 8 and is one side
that leads to the increase in the eccentricity amount and the
increase in the volume change amount of each of the plurality of
vane chambers 81). Assume that Fs represents this spring force. The
oil supplied from the discharge port 120 to the main gallery 14 can
be introduced into the control chamber 80 via the control passage
15. The cam ring 7 receives the pressure of the oil contained in
the control chamber 80. The cam ring 7 is biased by the
above-described hydraulic pressure toward the other side in the
direction of the rotation around the pin 72 (which is a clockwise
direction in FIG. 8 and is the other side that leads to the
reduction in the eccentricity amount and the reduction in the
volume change amount of each of the plurality of vane chambers 81).
Assume that Fp represents a force due to this hydraulic pressure (a
hydraulic force). The position of the cam ring 7 in the rotational
direction (the eccentricity amount, i.e., the capacity) is
determined mainly based on Fp and Fs. When Fp exceeds Fs, the cam
ring 7 swings toward the above-described other side in the
rotational direction, and the eccentricity amount (the capacity)
reduces. When Fp falls below Fs, the cam ring 7 swings toward the
above-described one side in the rotational direction, and the
eccentricity amount (the capacity) increases.
[0053] The control valve 17 can control the introduction of the oil
into the control chamber 80 and the discharge of the oil from the
control chamber 80. When the spool is located at the initial
position, the communication between the outlet port 174 (the
communication passage 154) and the inlet port 171 (the supply
passage 151) is blocked, and the communication between the outlet
port 174 and the discharge port 173 (the discharge passage 153) is
established. As a result, the oil can be discharged from inside the
control chamber 80 of the pump 1 via the communication passage 154
and the discharge passage 153. When the spool moves from the
initial position in the direction opposite from the biasing force
of the spring, the communication between the outlet port 174 and
the discharge port 173 is blocked, and the communication between
the outlet port 174 and the inlet port 171 is established. As a
result, the oil can be supplied from the main gallery 14 to inside
the control chamber 80 via the supply passage 151 and the
communication passage 154. The pressure in the main gallery 14 is
applied to the spool as a pilot pressure via the feedback passage
152. As a result, the position of the spool is subjected to
feedback control, and the eccentricity amount (the volume) is
adjusted. In other words, when the pressure in the main gallery 14
(the pilot pressure) increases, the spool moves in the direction
opposite from the biasing force of the spring. This movement causes
the oil to be supplied to the control chamber 80 to increase the
pressure in the control chamber 80, thereby increasing Fp and
reducing the eccentricity amount. On the other hand, when the
pressure in the main gallery 14 (the pilot pressure) reduces, the
spool moves in the same direction as the biasing force of the
spring. This movement causes the oil to be discharged from the
control chamber 80 to reduce the pressure in the control chamber
80, thereby reducing Fp and increasing the eccentricity amount. A
repetition of them allows the pressure in the main gallery 14 to be
kept at a constant value (within a predetermined range around the
constant value).
[0054] The solenoid portion changes the pressure in the main
gallery 14 when the spool starts moving by changing the strength of
the electromagnetic force. The electromagnetic force assists the
pilot pressure by biasing the spool in the direction opposite from
the spring. Therefore, according to an increase in the
electromagnetic force, the spool moves in the direction opposite
from the biasing force of the spring and causes a start of the oil
supply to the control chamber 80 with a further low pressure in the
main gallery 14 (the pilot pressure). As a result, the pressure in
the main gallery 14 is controlled to a further low constant value
(within a predetermined range around the constant value). The
engine control unit 19 calculates the required pressure in the main
gallery 14 according to driving conditions, such as the number of
rotations of the engine, a load, and an oil temperature and a water
temperature. The control unit 19 changes the value of the current
to supply to the solenoid portion (the strength of the
electromagnetic force) based on information input from the pressure
sensor 18 and the like and a built-in program. Due to this
mechanism, the control unit 19 can perform feedback control on the
pressure in the main gallery 14 to the above-described required
value. The control unit 19 can control the pressure in the main
gallery 14 continuously, so to speak, in a non-step manner.
Therefore, the pump 1 can achieve, for example, improvement of fuel
efficiency of the vehicle.
[0055] Next, a procedure of manufacturing the pump 1 will be
described. The manufacturing procedure includes a first process of
casting the housing main body 300 and the cover 301, a second
process of machining the housing main body 300 and the cover 301, a
third process of mounting the pump elements (the rotor 5 and the
like) into the pump element containing hole 362 of the housing main
body 300, and a fourth process of joining the cover 301 and the
housing main body 300 to each other. In the first process, the
housing main body 300 is cast by die-casting of an aluminum alloy.
Three dies are used. After molten metal is poured, a "first die for
forming the discharge passage portion 33 and the like together with
the pump element containing portion 31" is removed toward one side
in the axial direction of the driving shaft 4 (the z-axis positive
direction side). A "second die for forming the pump element
containing hole 362 and the discharge port 120 inside the pump
element containing portion 31 and also forming the first passage
12A inside the discharge passage portion 33" is removed toward the
other side in the axial direction of the driving shaft 4 (the
z-axis negative direction side). A "third die for forming the
second passage 12B in the discharge passage portion 33" is removed
in the axial direction of the second passage 12B (the y-axis
negative direction side) with respect to the discharge passage
portion 33. Work of removing the second die is easy, because the
pump 1 is configured in such a manner that the surface of the
discharge passage portion 33 on the y-axis positive direction side
is gradually displaced to the y-axis negative direction side as
extending toward the one side in the axial direction of the driving
shaft 4 (the z-axis positive direction side) while the surface of
the discharge passage position 33 on the y-axis negative direction
side is in parallel with the xz plane. Work of removing the second
die is easy, because the pump 1 is configured in such a manner that
the cross-sectional areas of the first passage 12A and the
discharge port 120 gradually reduce as they extend toward the one
side in the axial direction of the driving shaft 4 (the z-axis
positive direction side). Further, work of removing the third die
is easy, because the pump 1 is configured in such a manner that the
second passage 12B is opened on the surface of the discharge
passage portion 33 on the one side (the surface on the y-axis
negative direction side). The second process includes machining the
bearing portion 360, the surface of the discharge passage portion
33 on the y-axis negative direction side, and the inner peripheral
surface of the second passage 12B in the housing main body 300.
Processing (burring) the surface of the discharge passage portion
33 on the y-axis negative direction side and the inner peripheral
surface of the second passage 12B can contribute to improvement of
connectability (sealability and the like) of the member to the
opening of the second passage 12B.
[0056] The fourth process includes attaching the cover 301 to the
surface of the housing main body 300 on the z-axis negative
direction side at the first boss portions 351 with use of the bolts
30. The pins 356 can be inserted into both the pin holes 354 and
354, which allows the cover 301 to be positioned relative to the
housing main body 300. The cover 301 is integrated with the housing
main body 300 by being fastened by the bolts 30. The surface of the
cover 301 on the z-axis positive direction side closes the opening
of the pump element containing hole 362. In a process of mounting
the pump 1 onto the balancer module 2, the cover 301 of the housing
3 is joined to the lower housing 200 or the upper housing 201 of
the balancer module 2, or is joined to both the housings 200 and
201 while extending across them. The housing 3 is attached to the
front end surface of the housing 200 (201) (the surface on the
z-axis positive direction side) at the second boss portions 352 of
the housing main body 300 and the second boss portions 352 of the
cover 301 with use of the bolts 30. The bolts 30 also have a
function of fastening the boss portions 352 to 352 to each other.
The pin 357 can be inserted into the pin hole 355, which allows the
housing 3 to be positioned relative to the balancer module 2.
[0057] Next, advantageous effects will be described. The beginning
portion 12A1 of the first passage 12A of the discharge passage 12
is connected to the discharge port 120. The first passage 12A
extends as far as the termination portion 12A2 around the second
straight line 92. The second passage 12B is connected to the
termination portion 12A2, and is opened to outside the housing 3.
The second passage 12B functions as the discharge port that is
located at the termination portion of the discharge passage 12 and
is used to discharge the fluid out of the housing 3. As illustrated
in FIG. 18, in a case where the discharge passage 12 is shaped in
such a manner that the shape of the passage in cross section taken
along the direction perpendicular to the axis of the flow passage
discontinuously changes, i.e., there is an orthogonal step on the
inner wall of the passage, a swirl might be generated at this step.
This would undesirably result in an increase in a pressure loss
inside the pump 1 and thus a reduction in the discharge efficiency.
The reduction in the discharge efficiency of the pump 1 would also
lead to deterioration of the fuel efficiency. As illustrated in
FIG. 17, in the present embodiment, the shape of the first passage
12A in cross section taken along the direction perpendicular to the
second straight line 92 changes continuously from the beginning
portion 12A1 to the termination portion 12A2. In other words, there
is no portion that discontinuously changes (the orthogonal step) in
the direction in which the first passage 12A extends (the axial
direction of the flow passage) on the inner wall of the first
passage 12A (including the beginning portion 12A1 and the
termination portion 12A2). Therefore, the pump 1 can prevent the
pressure loss that otherwise would be caused by the step (the
generation of the swirl therefrom). In this manner, the
"continuous" change means that the change is not intermittent, and
the cross-sectional shape of the passage gradually (smoothly)
changes along the flow passage instead of sharply changing. The
rate of the above-described change does not necessarily have to be
constant. Further, the first passage 12A may partially include a
section where the cross-sectional shape is kept constant.
[0058] The above-described cross-sectional area of the first
passage 12A reduces as the first passage 12A extends from the
beginning portion 12A1 toward the termination portion 12A2 (from
the beginning portion 12A1 to the termination portion 12A2).
Therefore, the pump 1 can prevent a reduction in the flow speed in
the first passage 12A. The above-described cross-sectional area of
the first passage 12A gradually reduces as the first passage 12A
extends from the beginning portion 12A1 toward the termination
portion 12A2. In other words, the first passage 12A gradually
reduces in cross-sectional area as extending from the beginning
portion 12A1 toward the termination portion 12A2. As a result, the
pump 1 prevents a sharp change in the cross-sectional area in the
first passage 12A (including the beginning portion 12A1 and the
termination portion 12A2). Therefore, the pump 1 can prevent the
pressure loss because causing no sharp change in the flow speed and
thus preventing occurrence of a turbulent flow. The rate of the
above-described reduction does not necessarily have to be constant.
Further, the first passage 12A may partially include a section
where the cross-sectional area is kept constant. Even when there is
a portion where the cross-sectional shape discontinuously changes,
the advantageous effects can be maintained as long as this change
is sufficiently small.
[0059] The cross-sectional shape of the discharge port 120 changes
continuously as the discharge port 120 extends from the pump
element (the vane chambers 81) side toward the beginning portion
12A1 of the first passage 12A. Further, the above-described
cross-sectional area of the discharge port 120 gradually reduces as
the discharge port 120 extends from the pump element side toward
the beginning portion 12A1. Therefore, the above-descried
advantageous effects similar to the first passage 12A can also be
acquired at the discharge port 120. Similarly, the cross-sectional
shape of the connection portion between the discharge port 120 and
the beginning portion 12A1 of the first passage 12A changes
continuously between the discharge port 120 and the beginning
portion 12A1. In other words, the pump 1 can prevent the pressure
loss due to the step because there is no portion that changes
discontinuously in the axial direction of the flow passage on the
inner wall of this connection portion. Further, the pump 1 can
prevent the pressure loss due to the change in the cross-sectional
area because the cross-sectional area of the above-described
connection portion gradually reduces as the connection portion
extends from the discharge port 120 toward the beginning portion
12A1. It can be deemed that the discharge passage 12 starts from an
arbitrary position of the discharge port 120 in the z-axis
direction, and it can also be deemed that the discharge port 120
continues as far as an arbitrary position of the beginning portion
12A1 of the discharge passage 12 in the z-axis direction.
[0060] The housing 3 includes the housing main body 300 and the
cover 301. The housing main body 300 includes the discharge port
120, the first passage 12A, and the second passage 12B. In other
words, the discharge port 120, the first passage 12A, and the
second passage 12B are formed integrally with the housing main body
300. This eliminates the necessity of mounting a seal member for
improving the liquid tightness between the discharge port 120 and
the first passage 12A and between the first passage 12A and the
second passage 12B, thereby being able to prevent an increase in
the number of components, complication of the structure, and the
like. Further, this integration can further facilitate realization
of the configuration in which the above-described cross-sectional
shapes of the connection portion between the discharge port 120 and
the first passage 12A and the first passage 12A continuously change
(or the cross-sectional areas gradually reduce).
[0061] The above-described cross-sectional area of the first
passage 12A before it reaches the second passage 12B is equal to or
larger than the area of the second passage 12B in cross section
perpendicular to the third straight line 93. Therefore, the pump 1
can achieve a smooth flow of the fluid in the first passage 12A and
thus create an efficient flow by securing the cross-sectional area
of the first passage 12A. The area of the opening of the second
passage 12B at the termination portion 12A2 of the first passage
12A is equal to or smaller than the cross-sectional area of the
first passage 12A taken at the portion .alpha. of this opening that
is closest to the beginning portion 12A1, and is equal to or larger
than the cross-sectional area of the first passage 12A taken at the
farthest portion .beta. of the above-described opening from the
beginning portion 12A1. In other words, the cross-sectional area of
the termination portion 12A2 of the first passage 12A is
substantially equal to the area of the above-described opening of
the second passage 12B. Therefore, the pump 1 can prevent the
pressure loss due to the change in the cross-sectional area because
succeeding to prevent the sharp change in the cross-sectional area
of the flow passage at the connection portion between these
passages 12A and 12B.
[0062] In a case where there is a plurality of bent points of the
flow passage in the passage including the discharge passage 12 from
the pump elements to outside the housing 3 (the opening thereto),
such a configuration would undesirably result in an increase in the
pressure loss due to generation of a swirl at the bent points and
thus a reduction in the discharge efficiency. Further, this
configuration might lead to increases in the number of processes
and the cost for forming the passage. This configuration would
necessitate machining processing from a plurality of directions to
form one passage by connecting a plurality of (linear) passages,
thereby leading to an increase in the number of processing
procedures. A seal plug would become necessary to close an opening
to outside the housing 3 that would be generated at the time of the
processing. As a result, the number of components and the number of
assembling processes would increase, also leading to an increase in
the weight. In the present embodiment, the first passage 12A
extends around the second straight line 92, and the second passage
12B extends around the third straight line 93 (along the third
straight line 93). In this manner, the first passage 12A and the
second passage 12B each extend linearly. Therefore, there is only
one bent point of the flow passage in the discharge passage 12 at
most (one bent point between the first passage 12A and the second
passage 12B). The pump 1 can prevent the pressure loss due to the
bent passage (the generation of the swirl due to that) because
succeeding to maximumly reduce the number of bent points. Further,
the pump 1 can reduce the number of processes and the cost for
forming the discharge passage 12. The same also applies to the
example in which there is the step on the inner wall as illustrated
in FIG. 18. Further, the discharge port 120 extends around the
first straight line 91, and the first straight line 91 extends in
parallel with the second straight line 92. Therefore, the pump 1
can also reduce the number of bent points between the discharge
port 120 and the first passage 12A.
[0063] The second straight line 92 does not necessarily have to
extend along the axis 40 of the driving shaft 4. In other words,
the first passage 12A may extend around a straight line that is not
in parallel with the axis 40. In the case of the present
embodiment, the first passage 12A (the second straight line 92)
extends along the axis 40 (in parallel with the axis 40).
Therefore, the pump 1 can prevent an increase in the dimension of
the housing 3 in the radial direction of the driving shaft 4.
Similarly, the first straight line 91 does not necessarily have to
extend along the axis 40. In the case of the present embodiment,
the discharge port 120 (the first straight line 90) extends along
the axis 40. Therefore, the pump 1 can prevent the increase in the
dimension of the housing 3 in the radial direction of the driving
shaft 4.
[0064] The housing main body 300 includes the pump element
containing hole 362. The pump element containing hole 362 is the
recessed portion that contains the pump elements. The cover 301
closes the opening of the pump element containing hole 362. The
pump element containing hole 362 has the bottomed cylindrical shape
extending around the axis 40 of the driving shaft 4, and the
discharge port 120 is opened on the bottom surface 364 of the pump
element containing hole 362 in the axial direction of the driving
shaft 4. Therefore, the pump 1 can prevent the increase in the
dimension of the housing main body 300 in the radial direction of
the driving shaft 4, compared to when the discharge port 120 is
opened on the circumferential wall 311 of the pump element
containing hole 362. Further, the first passage 12A extending along
the axis 40 is opened on the bottom surface 364 of the pump element
containing hole 362 via the discharge port 120, which facilitates
the formation of the first passage 12A together with the pump
element containing hole 362 by the casting. Further, the present
configuration causes the fluid guided from the pump elements to the
discharge port 120 to mainly flow in the direction along the axis
40 inside the discharge port 120. This is the same as the direction
in which the fluid flows in the first passage 12A (the axial
direction of the flow passage). Therefore, the pump 1 can prevent
generation of a bent point of the flow passage at the connection
portion between the discharge port 120 and the first passage 12A
(the beginning portion 12A1).
[0065] The dimension of the discharge port 120 (extending along the
axis 40 of the driving shaft 4) is larger in the rotational
direction of the driving shaft 4 than in the radial direction of
the driving shaft 4. In other words, the cross section of the
discharge port 120 perpendicular to the first straight line 91 (in
parallel with the rotational axis of the pump elements) has the
flattened shape elongated in the rotational direction of the pump
elements. Therefore, the pump 1 can secure the above-described
cross-sectional area of the discharge port 120 while preventing the
increase in the dimension of the housing 3 in the radial direction
of the driving shaft 4, thereby achieving improvement of the
discharge efficiency. Similarly, the dimension of the first passage
12A (extending along the axis 40 of the driving shaft 4) is larger
in the rotational direction of the driving shaft 4 than in the
radial direction of the driving shaft 4. In other words, the cross
section of the first passage 12A perpendicular to the second
straight line 92 (in parallel with the rotational axis of the pump
elements) has the flattened shape elongated in the rotational
direction of the pump elements. Therefore, the pump 1 can secure
the above-described cross-sectional area of the first passage 12A
while preventing the increase in the dimension of the housing 3 in
the radial direction of the driving shaft 4, thereby achieving
improvement of the discharge efficiency. Now, the above-descried
cross section of the first passage 12A and the above-described
cross section of the discharge port 120 are shaped similarly to
each other (the flattened shape), which can further facilitate the
realization of the configuration in which the cross-sectional shape
of the connection portion between the discharge port 120 and the
first passage 12A (the beginning portion 12A1) continuously changes
(or the cross-sectional area thereof gradually changes).
[0066] The first passage 12A (the second straight line 92) is
eccentric toward the rotational direction side of the driving shaft
4 with respect to the discharge port 120 (the first straight line
91). Therefore, the pump 1 can improve the discharge efficiency
thereof. More specifically, the amount of the fluid guided from the
pump elements to the discharge port 120 is greater on the
rotational direction side (the termination side of the discharge
port 120) than on the opposite rotational direction side (the
beginning side of the discharge port 120) of the driving shaft 4.
Further, the fluid guided from the pump elements to the discharge
port 120 and flowing inside the discharge port 120 includes a
component in the rotational direction of the driving shaft 4
(inertial energy in the rotational direction). The first passage
12A (the center thereof) is eccentric toward the rotational
direction side of the driving shaft 4 with respect to the discharge
port 120 (the center thereof), which allows the fluid to be
efficiently guided from the pump elements to the first passage 12A
via the discharge port 120. Further, the first passage 12A easily
receives the inertial energy in the rotational direction, and
therefore the pressure loss can be reduced. The center of the
discharge port 120 (the first straight line 91) may be a center of
the discharge port 120 in cross section taken at an arbitrary
position in the z-axis direction without being limited to the
center of the opening, or may be an averaged position of these
centers.
[0067] At least a part in the rotational direction of the driving
shaft 4 in the wall on the outer side in the radial direction of
the driving shaft 4, among the walls forming the inner periphery of
the discharge port 120, is located on the outer side in the radial
direction of the driving shaft 4 with respect to the circular arc
.gamma. that is the circular arc centered at the axis 40 of the
driving shaft 4 and passes through the end on the outer side in the
radial direction of the driving shaft 4 in the beginning portion of
the discharge port 120 in the rotational direction of the driving
shaft 4. In other words, the outer side of the discharge port 120
in the radial direction of the driving shaft 4 bulges outward with
respect to the above-described circular arc .gamma.. Therefore, the
pump 1 can achieve improvement of the discharge efficiency and the
manufacturing efficiency. More specifically, the amount of the
fluid guided from the pump elements to the discharge port 120 is
greater on the outer side than on the inner side in the radial
direction of the driving shaft 4. Further, the fluid guided from
the pump elements to the discharge port 120 and flowing inside the
discharge port 120 contains a component directed outward in the
radial direction of the driving shaft 4 (inertial energy in the
radial direction). The discharge port 120 bulges outward in the
radial direction, which allows the fluid to be efficiently guided
from the pump elements to the first passage 12A via the discharge
port 120. Further, the discharge port 120 easily receives the
inertial energy in the radial direction, and therefore the pressure
loss can be reduced. More specifically, a part of the wall 126 on
the rotational direction side of the driving shaft 4, among the
walls on the outer side in the radial direction of the discharge
port 120, is located on the outer side in the radial direction with
respect to the above-described circular arc .gamma.. In other
words, the wall bulges more largely radially outward on the
rotational direction side (the termination side of the discharge
port 120) than on the opposite rotational direction side (the
beginning side of the discharge port 120) of the driving shaft 4.
Therefore, the pump 1 can further efficiently guide the fluid from
the pump elements to the first passage 12A via the discharge port
120, thereby receiving the inertial energy. Further, the discharge
port 120 bulges in the radial direction, which contributes to an
increase in the area of the opening of the discharge port 120 (the
area of the discharge port 120 as viewed from the axial direction
of the driving shaft 4) in the housing 3 (the bottom surface 364 of
the pump element containing hole 362). Therefore, the discharge
port 120 can be easily formed by the casting. In terms of this
effect, the discharge port 120 may bulge radially inward. The first
passage 12A also bulges radially outward at a part of the wall 126
on the outer side in the radial direction, similarly to the
discharge port 120. Therefore, the above-described advantageous
effects can also be achieved with respect to the first passage 12A.
The fluid can be efficiently guided from the pump elements to the
first passage 12A via the discharge port 120, and the first passage
12A easily receives the inertial energy of the fluid. Therefore,
the first passage 12A can be easily formed by the casting.
[0068] The first passage 12A is located inside the discharge
passage portion 33. The discharge passage portion 33 is the
plate-like flattened portion. Therefore, when the above-described
cross section of the first passage 12A has the flattened shape, the
pump 1 can reduce the thickness around the first passage 12A,
thereby achieving a reduction in the size of the housing 3 and
compactness thereof. The advantageous effects of the present
invention can be brought about as long as at least a part of the
first passage 12A is located inside the discharge passage portion
33. In the present embodiment, the first passage 12A is
approximately entirely located inside the discharge passage portion
33. Therefore, the above-described advantageous effects can be
maximized. The second passage 12B is located inside the discharge
passage portion 33. The second passage 12B is opened on the surface
of the discharge passage portion 33 on the one side (the y-axis
negative direction side). Therefore, the pump 1 can achieve a
reduction in the length of the second passage 12B, i.e., the
dimension from the first passage 12A (the termination portion 12A2)
to the above-described opening of the second passage 12B. The pump
1 can reduce the resistance in the flow passage (the pressure loss)
by shortening the second passage 12B. The third straight line 93
extends perpendicularly to the second straight line 92 (in the
y-axis direction). Therefore, the pump 1 can effectively shorten
the second passage 12B when the above-described surface of the
discharge passage portion 33 on the one side extends along the
second straight line 92 (the xz plane). Further, the pump 1 allows
the first passage 12A and the second passage 12B to be easily
formed. Further, the pump 1 can prevent an increase in the size of
the housing 3 in the direction of the second straight line 92 (the
axial direction of the driving shaft 4) due to the second passage
12B.
[0069] The bolt hole 333 is provided at the discharge passage
portion 33. The bolt for fixing the member connected to the
above-described opening of the second passage 12B to the discharge
passage portion 33 penetrates through the hole 333. The bulging
portions 331 and 332 around the holes 333 function as boss
portions. Therefore, a part of the discharge passage portion 33 can
be used as the boss portion (the fixation portion for fixing the
member), and therefore the boss portion (the fixation portion) does
not have to be additionally prepared on the housing 3. As a result,
the pump 1 can achieve the reduction in the size of the housing 3
and the compactness thereof.
[0070] The second passage 12B perpendicular to the third straight
line 93 is circular in cross section. Therefore, the pump 1 can
reduce a pressure loss (a frictional loss on the wall surface) in
the second passage 12B. Further, circularly shaping the
above-described cross section of the second passage 12B can
facilitate circularly shaping the opening of the second passage 12B
on the outer surface of the housing 3. Circularly shaping the
above-described opening can facilitate securing the continuity of
an external member to the passage.
[0071] The second passage 12B is opened to outside the housing 3 at
the position away from the driving shaft 4 in the axial direction
of the driving shaft 4 (the z-axis direction). Therefore, the pump
1 can prevent interference between the member connected to the
above-described opening of the second passage 12B and the driving
shaft 4, thereby facilitating the connection of the member. The
second passage 12B is opened to outside the housing 3 on the
driving shaft 4 side (the y-axis negative direction side) with
respect to the first passage 12A. Therefore, the pump 1 can further
effectively acquire the above-described advantageous effects. The
end portion of the driving shaft 4 (in the z-axis negative
direction) opposite from the end portion of the driving shaft 4 (in
the z-axis positive direction) in proximity to the above-described
opening of the second passage 12B in the axial direction of the
driving shaft 4 protrudes from the housing 3, and power is
transmitted from the driving source thereto. In other words, the
above-described end portion on the opposite side is connected to
the member for driving the driving shaft 4. Therefore, the pump 1
can ensure design flexibility. In other words, the pump 1 can
prevent interference between the member connected to the
above-described opening of the second passage 12B and the member
for driving the driving shaft 4. Further, the size and the position
of the above-described opening of the second passage 12B, i.e., the
length of the first passage 12A can be set freely according to the
prevention of this interference. More specifically, the first
passage 12A is formed at a location deep (in the axial direction of
the driving shaft 4) enough to form the discharge port having the
predetermined size (the opening of the second passage 12B). This
depth can be reduced. In other words, the pump 1 allows the
above-described opening of the second passage 12B to have a large
area while preventing an increase in the dimension of the housing 3
in the axial direction of the driving shaft 4.
[0072] The housing 3 (the flange portion 35) includes the first
boss portion 351, and the second boss portion 352 located at the
different position from the first boss portion 351. The bolt 30 for
coupling the cover 301 with the housing main body 300 penetrates
through the first boss portion 351. The bolt 30 for coupling the
housing 3 with another member (the housings 200 and 201 of the
balancer module 2) penetrates through the second boss portion 352.
Therefore, the assembling of the pump 1 and the mounting thereof
(to another member) can be realized with use of the different boss
portions (fixation portions) 351 and 352, respectively, which
contributes to improvement of workability of the assembling and the
mounting. The pump 1 includes two or more first boss portions 351
(three in the present embodiment). Therefore, the cover 301 and the
housing main body 300 can be coupled with each other with improved
strength. The first boss portions 351 are arranged around the pump
containing hole 362 in such a manner that the axis 40 of the
driving shaft 4 is interposed between them in the x-axis direction
and the y-axis direction. Therefore, the pump elements can be
further firmly held. The pump 1 includes two or more second boss
portions 352 (three in the present embodiment). Therefore, the
housing 3 (the pump 1) can be attached to another member (the
balancer module 2) with improved strength. The second boss portions
352 are disposed opposite of the axis 40 from each other in the
x-axis direction. Therefore, the pump 1 can be further firmly
mounted. The above-described coupling may be realized with use of a
fixation portion based on welding or the like without being limited
to the combination of the boss portion and the bolt.
[0073] The method for manufacturing the pump 1 includes the first
process of integrally forming the housing main body 300 by the
casting. Due to the manufacturing using the casting, the "discharge
port 120 opened to the pump element containing hole 362, which is
the recessed portion capable of rotatably containing the pump
elements, extending along the rotational axis 40 of the pump
elements, and shaped in such a manner that the cross section
thereof perpendicular to the axis 40 has the flattened shape
elongated in the rotational direction of the pump elements" and the
"first passage 12A extending along the rotational axis 40 of the
pump elements and shaped in such a manner that the cross section
thereof perpendicular to the axis 40 has the flattened shape
elongated in the rotational direction of the pump elements" can be
easily formed integrally with the "pump element containing hole
362". The present manufacturing method can omit the machining
process, and also eliminate the necessity of the sealing plug.
Further, due to the employment of the casting, the present
manufacturing method can easily realize the configuration in which
the cross-sectional shapes of the discharge port 120, the
connection portion between the discharge port 120 and the first
passage 12A, and the first passage 12A continuously change (or the
cross-sectional areas thereof gradually reduce). For example,
integrally forming the discharge port 120 and the first passage 12A
both having the flattened shapes in cross section with use of the
same (the second) die facilitates continuously (smoothly) shaping
the inner walls of these portions 120 and 12A. Especially, the
present manufacturing method can easily realize the configuration
in which the cross-sectional areas of the discharge port 120 and
the first passage 12A gradually reduce due to a draft angle of the
(second) die.
Second Embodiment
[0074] First, a configuration will be described. As illustrated in
FIGS. 19 to 21, the discharge passage portion 33 includes the main
body portion 330, a second passage portion 334, a first boss
portion 335, and a second boss portion 336. The main body portion
330 is the same as the first embodiment. The second passage portion
334 is cylindrical, and extends in the x-axis negative direction
from the x-axis negative direction side of the main body portion
330. The first passage 12A is located inside the main body portion
330, and the second passage 12B is located inside the second
passage portion 334. The first passage 12A is configured
identically to the first embodiment. The second passage 12B is
cylindrical, and extends in the x-axis direction (perpendicularly
to the second straight line 92). The second passage 12B is opened
on the wall of the first passage 12A on the x-axis negative
direction side, and is also opened on the surface of the second
passage portion 334 on the x-axis negative direction side. The
first boss portion 335 has a plate-like shape extending from the
end of the second passage portion 334 in the x-axis negative
direction toward the y-axis positive direction side and the z-axis
negative direction side, and extending along a yz plane. The second
boss portion 336 is connected to the y-axis negative direction side
and the z-axis positive direction side of the end of the second
passage portion 334 in the x-axis negative direction, and is
located opposite of the second passage portion 334 from the first
boss portion 335. A bolt hole 337 is provided at each of the boss
portions 335 and 336. The bolt hole 337 of the first boss portion
335 extends in the x-axis direction and penetrates through the
first boss portion 335. The bolt hole 337 of the second boss
portion 336 has a bottomed shape extending in the x-axis direction.
The boss portions 335 and 336 function as the fixation portions for
fixing the member connected to the opening of the second passage
12B together with the bolts. The other configuration is similar to
the first embodiment.
[0075] In the present embodiment, the second passage 12B extends in
the x-axis direction, thereby being opened on the outer surface of
the housing 3 at a horizontal position to the first passage 12A.
Therefore, the pump 1 can improve layout flexibility of the member
connected to the above-described opening of the second passage 12B,
i.e., layout flexibility of the pump 1 to the above-described
member. Besides them, the second embodiment can acquire similar
advantageous effects to the first embodiment by a similar
configuration to the first embodiment.
Other Embodiments
[0076] Having described the embodiments for implementing the
present invention with reference to the drawings, the specific
configuration of the present invention is not limited to the
embodiments, and the present invention also includes a design
modification and the like thereof made within a range that does not
depart from the spirit of the present invention, if any. Further,
the individual components described in the claims and the
specification can be arbitrarily combined or omitted within a range
that allows them to remain capable of achieving at least a part of
the above-described objects or producing at least a part of the
above-described advantageous effects. For example, the power
transmission mechanism that transmits the rotation of the
crankshaft to the balancer shaft (the driving-side shaft) is not
limited to the mechanism based on the meshed gears, and may be, for
example, a mechanism based on a sprocket or a chain. The target
member to which the pump (the housing) is attached is not limited
to the balancer module, and may be, for example, the cylinder
block. The pump may be employed for a hydraulic oil supply system
of a brake apparatus, a power steering apparatus, or the like
without being limited to the engine. The pump is not limited to the
vane pump, and may be, for example, a gear pump. Further, the pump
may be a fixed displacement pump. The specific method for casting
the housing main body may be any method. The casting is not limited
to the die-casting, and may be casting using a sand mold. The
material of the housing main body is not limited to the aluminum
alloy, and may be another material.
[0077] [Other Configurations Recognizable from Embodiments]
[0078] In the following description, other configurations
recognizable from the above-described embodiments will be
described.
(1) A pump configured to suck and discharge fluid, according to one
configuration thereof, includes a housing, a driving shaft
rotatably supported on the housing, and a pump element contained in
the housing and configured to be rotated by the driving shaft. The
housing contains therein an intake passage to which the fluid is
introduced from outside the housing, an intake port configured to
guide the fluid from the intake passage to the pump element, a
discharge port to which the fluid is introduced after being
pressurized by the pump element, and a discharge passage configured
to discharge the fluid delivered from the discharge port to outside
the housing. The discharge passage includes a first passage
including a beginning portion connected to the discharge port and a
termination portion while extending as far as the termination
portion around one straight line, and a second passage connected to
the termination portion of the first passage. The second passage is
opened to outside the housing. A shape of the first passage in
cross section taken along a direction perpendicular to the straight
line continuously changes from the beginning portion to the
termination portion. (2) According to another configuration, in the
above-described configuration, a cross-sectional shape of a
connection portion between the discharge port and the beginning
portion changes continuously between the discharge port and the
beginning portion. (3) According to another configuration, in any
of the above-described configurations, the straight line extends
along an axis of the driving shaft. (4) According to further
another configuration, in any of the above-described
configurations, the housing includes a housing main body including
a recessed portion. The recessed portion is a bottomed cylindrical
recessed portion extending around an axis of the driving shaft, and
contains the pump element. The housing further includes a cover
closing an opening of the recessed portion. The discharge port is
opened on a bottom surface of the recessed portion in an axial
direction of the driving shaft. (5) According to further another
configuration, in any of the above-described configurations, the
discharge port extends along an axis of the driving shaft. (6)
According to further another configuration, in any of the
above-described configurations, a dimension of the discharge port
in a rotational direction of the driving shaft is larger than a
dimension of the discharge port in a radial direction of the
driving shaft. A dimension of the first passage in the rotational
direction of the driving shaft is larger than a dimension of the
first passage in the radial direction of the driving shaft. (7)
According to further another configuration, in any of the
above-described configurations, the first passage is disposed on a
front side in the rotational direction of the driving shaft with
respect to the discharge port. (8) According to further another
configuration, in any of the above-described configurations, at
least a part of a wall on an outer side in the radial direction of
the driving shaft, among walls forming an inner periphery of the
discharge port, is located on the outer side in the radial
direction of the driving shaft with respect to a circular arc. The
circular arc is centered at the axis of the driving shaft. The
circular arc passes through an end on the outer side in the radial
direction of the driving shaft in the beginning portion of the
discharge port in the rotational direction of the driving shaft.
(9) According to further another configuration, in any of the
above-described configurations, the housing includes a plate-like
flattened portion. A part of the first passage and the second
passage are located inside the flattened portion. The second
passage is opened on a surface of the flattened portion on one
side. A fixation portion for fixing a member connected to an
opening of the second passage is provided at the flattened portion.
(10) According to further another configuration, in any of the
above-described configurations, the second passage is opened to
outside the housing at a position away from the driving shaft in
the axial direction of the driving shaft. (11) According to further
another configuration, in any of the above-described
configurations, a second end portion of the driving shaft on an
opposite side from a first end portion of the driving shaft that is
located close to the opening of the second passage in the axial
direction of the driving shaft protrudes from the housing, and is
connected to a member for driving the driving shaft. (12) According
to further another configuration, in any of the above-described
configurations, the second passage extends along one straight line.
(13) According to further another configuration, in any of the
above-described configurations, an area of the cross section of the
first passage reduces as the first passage extends from the
beginning portion to the termination portion. (14) According to
further another configuration, in any of the above-described
configurations, the second passage extends in a direction different
from a direction in which the first passage extends. An area of an
opening of the second passage at the termination portion of the
first passage is equal to or smaller than an area of the first
passage in cross section taken at a portion of the opening of the
second passage at the termination portion of the first passage that
is located closest to the beginning portion of the first passage,
and is equal to or larger than an area of the first passage in
cross section taken at a portion of the opening of the second
passage at the termination portion of the first passage that is
located farthest from the beginning portion of the first passage.
(15) According to further another configuration, in any of the
above-described configurations, the housing includes a housing main
body including a recessed portion containing the pump element, a
cover closing an opening of the recessed portion, a first fixation
portion for fixing the cover to the housing main body, and a second
fixation portion for fixing the housing to another member at a
different position from the first fixation portion. (16) Further,
from another aspect, a pump configured to pressurize and discharge
sucked fluid, according to one configuration thereof, includes a
housing, a shaft rotatably supported on the housing, and a pump
element contained in the housing and coupled with the shaft. The
housing contains therein an intake passage for introducing the
fluid from outside the housing to the pump element, and a discharge
passage for discharging the fluid pressurized by the pump element
to outside the housing. The discharge passage includes a first
passage extending around one straight line and including a
beginning portion on one side where the pump element is located,
and a termination portion. The first passage is shaped in such a
manner that an area of a cross section thereof perpendicular to the
straight line gradually reduces as the first passage extends from
the beginning portion toward the termination portion. The discharge
passage further includes a second passage connected to the
termination portion of the first passage and opened to outside the
housing. (17) According to another configuration, in the
above-described configuration, the straight line extends along an
axis of the shaft. A dimension of the first passage in a rotational
direction of the shaft is larger than a dimension of the first
passage in a radial direction of the shaft. (18) Further, from
another aspect, a pump configured to pressurize and discharge
sucked fluid, according to one configuration thereof, includes a
housing and a pump element rotatably contained in the housing. The
housing includes an intake passage for introducing the fluid to the
pump element, and a discharge port extending around a first
straight line in parallel with a rotational axis of the pump
element. The fluid pressurized by the pump element is introduced
into the discharge port. The discharge port has a flattened shape
elongated in a rotational direction of the pump element in cross
section perpendicular to the first straight line. The housing
further includes a discharge passage for discharging the fluid
introduced into the discharge port to outside the housing. The
discharge passage includes a first passage connected to the
discharge port and extending around a second straight line in
parallel with the rotational axis of the pump element. The first
passage has a flattened shape elongated in the rotational direction
of the pump element in cross section perpendicular to the second
straight line. The discharge passage further includes a second
passage connected to the first passage and extending around a third
straight line to be opened on an outer surface of the housing. (19)
According to another aspect, in the above-described configuration,
a shape of a connection portion between the discharge port and the
first passage in cross section perpendicular to the rotational axis
of the pump element changes continuously between the discharge port
and the first passage. (20) According to another configuration, in
any of the above-described configurations, the pump includes a
driving shaft rotatably supported on the housing and configured to
rotate the pump element. The second passage is opened on the outer
surface of the housing on one side where the driving shaft is
located with respect to the first passage. A second end portion of
the driving shaft on an opposite side from a first end portion in
proximity to the opening of the second passage protrudes from the
housing, and power is transmitted from a driving source thereto.
(21) According to further another configuration, in any of the
above-described configurations, the housing includes a housing main
body including a recessed portion containing the pump element, the
discharge port, the first passage, and the second passage. The
housing further includes a cover closing an opening of the recessed
portion. (22) According to further another configuration, in any of
the above-described configurations, the second passage
perpendicular to the third straight line is circular in cross
section. (23) A method for manufacturing a pump, according to one
configuration thereof, includes forming a housing main body
integrally by casting. The housing main body includes a recessed
portion capable of rotationally containing a pump element, an
intake port opened on the recessed portion, a discharge port opened
on the recessed portion and extending along a rotational axis of
the pump element while having a flattened shape elongated in a
rotational direction of the pump element in cross section
perpendicular to the rotational axis of the pump element, a first
passage connected to the discharge port and extending along the
rotational axis of the pump element while having a flattened shape
elongated in the rotational direction of the pump element in cross
section perpendicular to the rotational axis of the pump element,
and a second passage connected to the first passage and extending
linearly to be opened on an outer surface of the housing. The
method further includes mounting the pump element into the recessed
portion, and closing an opening of the recessed portion with a
cover.
[0079] The present application claims priority under the Paris
Convention to Japanese Patent Application No. 2017-135504 filed on
Jul. 11, 2017.
The entire disclosure of Japanese Patent Application No.
2017-135504 filed on Jul. 11, 2017 including the specification, the
claims, the drawings, and the abstract is incorporated herein by
reference in its entirety.
REFERENCE SIGN LIST
[0080] 1 pump [0081] 3 housing [0082] 4 driving shaft [0083] 40
axis [0084] 5 rotor (pump element) [0085] 6 vane (pump element)
[0086] 11 intake passage [0087] 110 intake port [0088] 12 discharge
passage [0089] 12A first passage [0090] 12A1 beginning portion
[0091] 12A2 termination portion [0092] 12B second passage [0093]
120 discharge port
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