U.S. patent application number 14/134439 was filed with the patent office on 2014-06-26 for rotary pump and brake device having the same.
This patent application is currently assigned to DENSO CORPORATION. The applicant listed for this patent is Advics Co., Ltd., DENSO CORPORATION, Nippon Soken, Inc.. Invention is credited to Naoki Hakamada, Tomoaki Kawabata, Yasuhiro Kawase, Kazuhide Uchida, Kazunori Uchiyama, Takahiro Yamaguchi.
Application Number | 20140178236 14/134439 |
Document ID | / |
Family ID | 50974871 |
Filed Date | 2014-06-26 |
United States Patent
Application |
20140178236 |
Kind Code |
A1 |
Uchiyama; Kazunori ; et
al. |
June 26, 2014 |
ROTARY PUMP AND BRAKE DEVICE HAVING THE SAME
Abstract
A rotary pump includes a first side plate and a second side
plate between which an outer rotor and an inner rotor are arranged.
The second side plate has a concave portion on a surface adjacent
to a maximum gap portion relative to a drive shaft. The concave
portion is located in an outer teeth passing section which is
defined between a line on which a teeth tip of an outer teeth part
of the inner rotor passes in response to rotation of the inner
rotor and a line on which a teeth bottom of the outer teeth part of
the inner rotor passes in response to rotation of the inner rotor.
The concave portion communicates with one of a plurality of gap
portions while the inner rotor is rotated.
Inventors: |
Uchiyama; Kazunori;
(Okazaki-city, JP) ; Hakamada; Naoki; (Anjo-city,
JP) ; Uchida; Kazuhide; (Hamamatsu-city, JP) ;
Kawase; Yasuhiro; (Nishio-city, JP) ; Yamaguchi;
Takahiro; (Kariya-city, JP) ; Kawabata; Tomoaki;
(Takahama-city, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DENSO CORPORATION
Advics Co., Ltd.
Nippon Soken, Inc. |
Kariya-city
Kariya-city
Nishio-city |
|
JP
JP
JP |
|
|
Assignee: |
DENSO CORPORATION
Kariya-city
JP
Advics Co., Ltd.
Kariya-city
JP
Nippon Soken, Inc.
Nishio-city
JP
|
Family ID: |
50974871 |
Appl. No.: |
14/134439 |
Filed: |
December 19, 2013 |
Current U.S.
Class: |
418/191 |
Current CPC
Class: |
F04C 2/102 20130101;
F01C 21/08 20130101; F04C 2/086 20130101; F04C 15/0015 20130101;
F04C 15/0026 20130101 |
Class at
Publication: |
418/191 |
International
Class: |
F04C 18/00 20060101
F04C018/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 25, 2012 |
JP |
2012-281303 |
Claims
1. A rotary pump comprising: a rotary portion including an outer
rotor having an inner teeth part on an inner perimeter, an inner
rotor having an outer teeth part on an outer perimeter, the inner
rotor having a rotation axis corresponding to a drive shaft, a
plurality of gap portions being defined between the inner teeth
part and the outer teeth part and having a maximum gap portion
which has a maximum volume among the plurality of gap portions; a
casing covering the rotary portion and having a first side plate
and a second side plate between which the outer rotor and the inner
rotor are arranged, the second side plate having a contact surface
in contact with the outer rotor and the inner rotor so as to
achieve a mechanical sealing, and a central plate arranged to
surround an outer perimeter of the outer rotor, the casing having
an intake port through which fluid is drawn toward the rotary
portion and a discharge port through which fluid is discharged from
the rotary portion; and a seal component arranged between the first
side plate and the rotary portion to define a low pressure part
connected to the intake port and a high pressure part connected to
the discharge port, wherein the second side plate has a concave
portion on the contact surface adjacent to the maximum gap portion
relative to the drive shaft, the concave portion is located in an
outer teeth passing section which is defined between a line on
which a teeth tip of the outer teeth part of the inner rotor passes
in response to rotation of the inner rotor and a line on which a
teeth bottom of the outer teeth part of the inner rotor passes in
response to rotation of the inner rotor, and the concave portion
communicates with one of the plurality of gap portions while the
inner rotor is rotated.
2. The rotary pump according to claim 1, wherein the concave
portion communicates with only one of the plurality of gap
portions, and does not simultaneously communicate with two of the
plurality of gap portions.
3. The rotary pump according to claim 1, wherein the concave
portion has a width dimension in a rotational direction, and the
width dimension of the concave portion is smaller than a teeth
width dimension of the outer teeth part and the inner teeth part in
the rotational direction.
4. The rotary pump according to claim 1, wherein the outer rotor
has a center axis and the inner rotor has a center axis, a center
line being defined by connecting the center axis of the outer rotor
and the center axis of the inner rotor with each other, and the
concave portion is located adjacent to the discharge port with
respect to the center line.
5. A brake device comprising: the rotary pump according to claim 1;
a brake fluid pressure generator which generates a brake fluid
pressure based on a depression force; a braking force generator
which generates a braking force to a wheel based on the brake fluid
pressure; a main conduit connected to the brake fluid pressure
generator to transmit the brake fluid pressure to the braking force
generator; and an auxiliary conduit connected to the brake fluid
pressure generator to supply brake fluid to the main conduit so as
to raise the braking force generated by the braking force
generator, wherein the rotary pump is arranged to draw the brake
fluid at the intake port from the brake fluid pressure generator
through the auxiliary conduit and to discharge the brake fluid at
the discharge port toward the braking force generator through the
main conduit.
6. A rotary pump comprising: a rotary portion including an outer
rotor having an inner teeth part on an inner perimeter, an inner
rotor having an outer teeth part on an outer perimeter, the inner
rotor having a rotation axis corresponding to a drive shaft, a
plurality of gap portions being defined between the inner teeth
part and the outer teeth part and having a maximum gap portion
which has a maximum volume among the plurality of gap portions; a
casing covering the rotary portion and having a first side plate
and a second side plate between which the outer rotor and the inner
rotor are arranged, the second side plate having a contact surface
in contact with the outer rotor and the inner rotor so as to
achieve a mechanical sealing, and a central plate arranged to
surround an outer perimeter of the outer rotor, the casing having
an intake port through which fluid is drawn toward the rotary
portion and a discharge port through which fluid is discharged from
the rotary portion; and a seal component arranged between the first
side plate and the rotary portion to define a low pressure part
connected to the intake port and a high pressure part connected to
the discharge port, wherein the second side plate has a concave
portion on the contact surface adjacent to the maximum gap portion
relative to the drive shaft, the concave portion is located in an
inner teeth passing section which is defined between a line on
which a teeth tip of the inner teeth part of the outer rotor passes
in response to rotation of the outer rotor and a line on which a
teeth bottom of the inner teeth part of the outer rotor passes in
response to rotation of the outer rotor, and the concave portion
communicates with one of the plurality of gap portions while the
inner rotor is rotated.
7. The rotary pump according to claim 6, wherein the concave
portion communicates with only one of the plurality of gap
portions, and does not simultaneously communicate with two of the
plurality of gap portions.
8. The rotary pump according to claim 6, wherein the concave
portion has a width dimension in a rotational direction, and the
width dimension of the concave portion is smaller than a teeth
width dimension of the outer teeth part and the inner teeth part in
the rotational direction.
9. The rotary pump according to claim 6, wherein the outer rotor
has a center axis and the inner rotor has a center axis, a center
line being defined by connecting the center axis of the outer rotor
and the center axis of the inner rotor with each other, and the
concave portion is located adjacent to the discharge port with
respect to the center line.
10. A brake device comprising: the rotary pump according to claim
6; a brake fluid pressure generator which generates a brake fluid
pressure based on a depression force; a braking force generator
which generates a braking force to a wheel based on the brake fluid
pressure; a main conduit connected to the brake fluid pressure
generator to transmit the brake fluid pressure to the braking force
generator; and an auxiliary conduit connected to the brake fluid
pressure generator to supply brake fluid to the main conduit so as
to raise the braking force generated by the braking force
generator, wherein the rotary pump is arranged to draw the brake
fluid at the intake port from the brake fluid pressure generator
through the auxiliary conduit and to discharge the brake fluid at
the discharge port toward the braking force generator through the
main conduit.
11. A rotary pump comprising: a rotary portion including an outer
rotor having an inner teeth part on an inner perimeter, an inner
rotor having an outer teeth part on an outer perimeter, the inner
rotor having a rotation axis corresponding to a drive shaft, a
plurality of gap portions being defined between the inner teeth
part and the outer teeth part and having a minimum gap portion
which has a minimum volume among the plurality of gap portions; a
casing covering the rotary portion and having a first side plate
and a second side plate between which the outer rotor and the inner
rotor are arranged, the second side plate having a contact surface
in contact with the outer rotor and the inner rotor so as to
achieve a mechanical sealing, and a central plate arranged to
surround an outer perimeter of the outer rotor, the casing having
an intake port through which fluid is drawn toward the rotary
portion and a discharge port through which fluid is discharged from
the rotary portion; and a seal component arranged between the first
side plate and the rotary portion to define a low pressure part
connected to the intake port and a high pressure part connected to
the discharge port, wherein the second side plate has a concave
portion on the contact surface adjacent to the minimum gap portion
relative to the drive shaft, the concave portion is located in an
overlap area in which an inner teeth passing section and an outer
teeth passing section are overlapped with each other, the inner
teeth passing section being defined between a line on which a teeth
tip of the inner teeth part of the outer rotor passes in response
to rotation of the outer rotor and a line on which a teeth bottom
of the inner teeth part of the outer rotor passes in response to
rotation of the outer rotor, the outer teeth passing section being
defined between a line on which a teeth tip of the outer teeth part
of the inner rotor passes in response to rotation of the inner
rotor and a line on which a teeth bottom of the outer teeth part of
the inner rotor passes in response to rotation of the inner rotor,
and the concave portion communicates with one of the plurality of
gap portions while the inner rotor is rotated.
12. The rotary pump according to claim 11, wherein the concave
portion communicates with only one of the plurality of gap
portions, and does not simultaneously communicate with two of the
plurality of gap portions.
13. The rotary pump according to claim 11, wherein the concave
portion has a width dimension in a rotational direction, and the
width dimension of the concave portion is smaller than a teeth
width dimension of the outer teeth part and the inner teeth part in
the rotational direction.
14. The rotary pump according to claim 11, wherein the outer rotor
has a center axis and the inner rotor has a center axis, a center
line being defined by connecting the center axis of the outer rotor
and the center axis of the inner rotor with each other, and the
concave portion is located adjacent to the discharge port with
respect to the center line.
15. A brake device comprising: the rotary pump according to claim
11; a brake fluid pressure generator which generates a brake fluid
pressure based on a depression force; a braking force generator
which generates a braking force to a wheel based on the brake fluid
pressure; a main conduit connected to the brake fluid pressure
generator to transmit the brake fluid pressure to the braking force
generator; and an auxiliary conduit connected to the brake fluid
pressure generator to supply brake fluid to the main conduit so as
to raise the braking force generated by the braking force
generator, wherein the rotary pump is arranged to draw the brake
fluid at the intake port from the brake fluid pressure generator
through the auxiliary conduit and to discharge the brake fluid at
the discharge port toward the braking force generator through the
main conduit.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Application No.
2012-281303 filed on Dec. 25, 2012, the disclosure of which is
incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] The present disclosure relates to a rotary pump and a brake
device having the rotary pump.
BACKGROUND
[0003] An inscribed-gear rotary pump such as trochoid pump has an
inner rotor, an outer rotor and a casing. The inner rotor has an
outer teeth part around the outer perimeter, and the outer rotor
has an inner teeth part around the inner perimeter. The casing has
a first side plate, a second side plate, and a central plate, and
the outer rotor and the inner rotor are arranged in the casing in a
manner that the inner teeth part and the outer teeth part mesh with
each other such that plural gap portions are defined between the
inner teeth part and the outer teeth part.
[0004] In such a rotary pump, it is necessary to seal a space
between a high pressure part and a low pressure part. The first
side plate has a seal component which is pressed onto one axial
surface of the rotary pump for the sealing, and the other axial
surface is directly pressed onto the second side plate for
achieving the mechanical sealing. The central plate has a concave
portion in which a seal component is arranged, and the seal
component is in contact with the outer perimeter of the outer rotor
for the sealing.
[0005] However, if the pressing force from the rotors to the
respective side plates becomes large, loss in the rotational torque
becomes large, since the mechanical sealing is adopted. If heat is
generated at the mechanical sealing, the heated part may expand,
and the expansion may reduce the pump discharge capability.
[0006] JP 4007080 B (US 2003/0227216 A1) describes that a discharge
groove is defined on a side plate at positions corresponding to the
plural gap portions into which discharge pressure is introduced, so
as to reduce the loss in the rotational torque. Thus, the outer
rotor and the inner rotor can be pressed back toward the seal
component by the discharge pressure on the surface adjacent to the
mechanical sealing, so the frictional resistance can be reduced
between the axial end surface of the outer rotor and the end
surface of the side plate. Therefore, the loss in the rotational
torque can be reduced between the respective rotors and the side
plate, and the pump discharge capability can be restricted from
being lowered.
[0007] However, friction is also generated at positions not
corresponding to the plural gap portions. For this reason, it is
required to further reduce the contact resistance at the mechanical
sealing between the side plate and the respective rotor.
SUMMARY
[0008] It is an object of the present disclosure to provide a
rotary pump in which contact resistance and wear amount are reduced
between a casing and a rotor. It is another object of the present
disclosure to provide a brake device having the rotary pump.
[0009] According to a first example of the present disclosure, a
rotary pump includes a rotary portion, a casing and a seal
component. The rotary portion includes an outer rotor having an
inner teeth part on an inner perimeter, and an inner rotor having
an outer teeth part on an outer perimeter. The inner rotor has a
rotation axis corresponding to a drive shaft. A plurality of gap
portions is defined between the inner teeth part and the outer
teeth part and has a maximum gap portion which has a maximum volume
among the plurality of gap portions. The casing covers the rotary
portion and has a first side plate and a second side plate between
which the outer rotor and the inner rotor are arranged and a
central plate arranged to surround an outer perimeter of the outer
rotor. The second side plate has a contact surface in contact with
the outer rotor and the inner rotor so as to achieve a mechanical
sealing. The casing has an intake port through which fluid is drawn
into the rotary portion and a discharge port through which fluid is
discharged from the rotary portion. The seal component is arranged
between the first side plate and the rotary portion to define a low
pressure part connected to the intake port and a high pressure part
connected to the discharge port. The second side plate has a
concave portion on the contact surface adjacent to the maximum gap
portion relative to the drive shaft. The concave portion is located
in an outer teeth passing section which is defined between a line
on which a teeth tip of the outer teeth part of the inner rotor
passes in response to rotation of the inner rotor and a line on
which a teeth bottom of the outer teeth part of the inner rotor
passes in response to rotation of the inner rotor. The concave
portion communicates with one of the plurality of gap portions
while the inner rotor is rotated.
[0010] Thus, since the concave portion is defined in the end
surface of the second side plate, when the concave portion and the
gap portion communicate with each other, the brake fluid contained
in the gap portion is supplied into the concave portion. Thereby,
it becomes possible to make the brake fluid intervene between the
second side plate and the inner rotor, and the brake fluid
functions as lubricating oil. Thus, the frictional resistance of
the contact part between the second side plate and the inner rotor
can be reduced. Therefore, it becomes possible to decrease the
amount of wear between the second side plate and the inner
rotor.
[0011] According to a second example of the present disclosure, the
concave portion is located in an inner teeth passing section which
is defined between a line on which a teeth tip of the inner teeth
part of the outer rotor passes in response to rotation of the outer
rotor and a line on which a teeth bottom of the inner teeth part of
the outer rotor passes in response to rotation of the outer rotor,
and the concave portion communicates with one of the plurality of
gap portions while the inner rotor is rotated.
[0012] Similarly, when the concave portion and the gap portion
communicate with each other, the brake fluid contained in the gap
portion is supplied into the concave portion. Thereby, it becomes
possible to make the brake fluid intervene between the second side
plate and the outer rotor, and the brake fluid functions as
lubricating oil. The frictional resistance of the contact part
between the second side plate and the outer rotor can be reduced.
Therefore, it becomes possible to decrease the amount of wear
between the second side plate and the outer rotor.
[0013] The concave portion communicates with only the one of the
plurality of gap portions, and does not simultaneously communicate
with the plurality of gap portions. Therefore, the compression
performance can be prevented from being lowered in the gap
portions.
[0014] According to a third example of the present disclosure, the
concave portion is located in an overlap area in which the outer
teeth passing section and the inner teeth passing section overlap
with each other
[0015] According to a fourth example of the present disclosure, a
brake device includes the rotary pump, a brake fluid pressure
generator which generates a brake fluid pressure based on a
depression force, a braking force generator which generates a
braking force to a wheel based on the brake fluid pressure, a main
conduit connected to the brake fluid pressure generator to transmit
the brake fluid pressure to the braking force generator, and an
auxiliary conduit connected to the brake fluid pressure generator
to supply brake fluid to the main conduit so as to raise the
braking force generated by the braking force generator. The rotary
pump is arranged to draw the brake fluid at the intake port from
the brake fluid pressure generator through the auxiliary conduit
and to discharge the brake fluid at the discharge port toward the
braking force generator through the main conduit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above and other objects, features and advantages of the
present disclosure will become more apparent from the following
detailed description made with reference to the accompanying
drawings. In the drawings:
[0017] FIG. 1 is a view illustrating a brake device having a rotary
pump according to a first embodiment;
[0018] FIG. 2A is a cross-sectional view illustrating the rotary
pump;
[0019] FIG. 2B is a cross-sectional view taken along a line
IIB-O-IIB of FIG. 2A;
[0020] FIG. 2C is a cross-sectional view taken along a line IIC-IIC
of FIG. 2B;
[0021] FIG. 3 is an enlarged view illustrating the rotary pump in
which a concave portion is defined in a second side plate;
[0022] FIG. 4 is an enlarged view illustrating a comparative
example of the concave portion;
[0023] FIG. 5 is a cross-sectional view illustrating a rotary pump
according to a second embodiment;
[0024] FIG. 6 is an enlarged view illustrating the rotary pump of
the second embodiment in which a concave portion is defined in a
second side plate; and
[0025] FIG. 7 is a cross-sectional view illustrating a rotary pump
according to a third embodiment.
DETAILED DESCRIPTION
[0026] Embodiments of the present disclosure will be described
hereafter referring to drawings. In the embodiments, a part that
corresponds to a matter described in a preceding embodiment may be
assigned with the same reference numeral, and redundant explanation
for the part may be omitted. When only a part of a configuration is
described in an embodiment, another preceding embodiment may be
applied to the other parts of the configuration. The parts may be
combined even if it is not explicitly described that the parts can
be combined. The embodiments may be partially combined even if it
is not explicitly described that the embodiments can be combined,
provided there is no harm in the combination.
(First Embodiment)
[0027] A brake device is explained with reference to FIG. 1. The
brake device is applied to a vehicle equipped with a hydraulic
circuit of a diagonal piping system having a first pipe connecting
wheel cylinders of a front-right wheel and a rear-left wheel and a
second pipe connecting wheel cylinders of a front-left wheel and a
rear-right wheel. Alternatively, the brake device may be applied to
other system, other than the diagonal piping system, such as
straight pipe connecting a front part and a rear part.
[0028] As shown in FIG. 1, a brake pedal 1 is connected to a
booster 2 that boosts brake depression force. The booster 2 has a
pushrod which transmits the boosted depression force to a master
cylinder (M/C) 3. M/C pressure is generated when the pushrod
presses a master piston of the M/C 3. The M/C pressure is
transmitted to a wheel cylinder (W/C) 4 for the front-right wheel
FR, and a wheel cylinder (WIC) 5 for the rear-left wheel RL through
an actuator which controls the brake fluid pressure so as to
perform antilock brake system (ABS) control. A master reservoir 3a
is connected to the MIC 3, and supplies brake fluid to the M/C 3 or
stores extra brake fluid.
[0029] The brake pedal 1, the booster 2, and the M/C 3 may
correspond to a brake fluid pressure generator. The W/C 4 and the
W/C 5 may correspond to a braking force generator.
[0030] The following explanation is based on a first piping system
which connects the front-right wheel FR to the rear-left wheel RL.
The explanation for a second piping system (SPS) which connects the
front-left wheel FL to the rear-right wheel RR is omitted, which is
similar to the explanation for the first piping system.
[0031] The brake device is equipped with a main conduit A connected
to the M/C 3. A differential pressure control valve 22 and a check
valve 22a are arranged in the main conduit A. The differential
pressure control valve 22 is controlled by a brake electrical
control unit (ECU). The main conduit A is divided into two parts at
the differential pressure control valve 22. Specifically, the main
conduit A has a first conduit Al which receives the M/C pressure in
a section from the M/C 3 to the differential pressure control valve
22, and a second conduit A2 in a section from the differential
pressure control valve 22 to each of the W/C 4 and the W/C 5.
[0032] The differential pressure control valve 22 is usually in the
communicating state. In a case where the M/C pressure is lower than
a predetermined pressure, when the W/C 4 and the W/C 5 are suddenly
braked, or when in the traction control, the differential pressure
control valve 22 generates a predetermined pressure difference
between the section of the M/C 3 and the section of the W/C 4, 5
(in the differential state). The differential pressure control
valve 22 can linearly adjust a preset value set for the
differential pressure.
[0033] Moreover, the second conduit A2 is further branched to two
parts. A pressure increase control valve 30 for controlling an
increase of brake fluid pressure of the W/C 4 is installed to one
of the branched conduits and a pressure increase control valve 31
for controlling an increase of brake fluid pressure of the W/C 5 is
installed to the other of the branched conduits.
[0034] The pressure increase control valve 30, 31 is a two-position
valve capable of controlling communication and shut-off states by
the brake ECU. When the two-position valve is controlled to a
communicating state, the M/C pressure or a brake fluid pressure
produced by a pump 10 can be applied to the respective W/C 4, 5. In
the normal braking operation where the ABS is not controlled by the
ECU, each of the pressure increase control valves 30 and 31 is
always controlled in the communicating state as a normally-open
valve.
[0035] Safety valves 30a and 31 a are installed in parallel to the
pressure increase control valves 30 and 31, respectively. The
safety valve 30a or 31a allows the brake fluid to swiftly return
from the W/C 4 or 5 to the M/C 3 when the ABS control has been
finished by stopping depression of the brake pedal 1.
[0036] Pressure reduction control valve 32 or 33 capable of
controlling communication and shut-off states by the brake ECU is
arranged at an intake conduit B connecting the second conduit A2
between the pressure increase control valve 30 or 31 and the W/C 4
or 5 to a pressure control reservoir 40. In the normal braking
operation where the ABS control is not operated, the pressure
reduction control valves 32 and 33 are always brought into a
shut-off state as normally-close valve.
[0037] A rotary pump 10 is arranged in an auxiliary conduit C which
connects the main conduit A between the differential pressure
control valve 22 and the pressure increase control valve 30, 31 to
the pressure control reservoir 40. The discharge port side of the
rotary pump 10 is equipped with a safety valve 10A which prohibits
the brake fluid from flowing backward. A motor 11 is connected to
the rotary pump 10, and the rotary pump 10 is driven by the motor
11.
[0038] An auxiliary conduit D is defined to connect the pressure
control reservoir 40 to the M/C 3, and a two-position valve 23 is
arranged in the auxiliary conduit D. The two-position valve 23 is a
normally-close valve which is closed at a normal time, and is
driven at a brake assistance time or at a traction control time. At
this time, the two-position valve 23 is in the communicating state
to change the auxiliary conduit D into the communicating state.
Further, the rotary pump 10 is operated in the state where the
pressure difference is maintained by the pressure difference
control valve 22 between the M/C 3 and the W/C 4, 5. Thereby, the
brake fluid of the first conduit Al is drawn up through the
auxiliary conduit D, and is discharged out to the second conduit
A2. Therefore, the pressure in the W/C 4, 5 can be made higher than
the M/C pressure, such that the wheel braking force can be
increased.
[0039] The pressure control reservoir 40 controls the pressure
difference between the brake fluid pressure in the reservoir and
the M/C pressure, and supplies the brake fluid to the rotary pump
10. The pressure control reservoir 40 has reservoir holes 40a and
40b which communicate with a reservoir chamber 40c of the pressure
control reservoir 40. The reservoir hole 40a is connected to the
auxiliary conduit D, and receives the brake fluid flowing from the
M/C 3. The reservoir hole 40b is connected to the intake conduit B
and the auxiliary conduit C, and receives the brake fluid
discharged from the W/C 4, 5 and supplies the brake fluid to the
intake side of the rotary pump 10.
[0040] On the inner side of the reservoir hole 40a, a valve object
41 such as ball valve is arranged. The communication or
interception state between the auxiliary conduit D and the
reservoir chamber 40c is controlled by the separation or the
seating of the valve object 41 relative to a valve seat 42. The
pressure difference between the inner pressure in the reservoir
chamber 40c and the M/C pressure is controlled by controlling a
distance between the valve seat 42 and the valve object 41.
[0041] A rod 43 is provided on the lower side of the valve object
41 as a separate object separated from the valve object 41. The rod
43 has a predetermined stroke for moving the valve object 41 up and
down. A piston 44 and a spring 45 are disposed in the reservoir
chamber 40c. The piston 44 is interlocked with the rod 43. The
spring 45 generates power which pushes out the brake fluid from the
reservoir chamber 40c by pressing the piston 44 toward the valve
object 41.
[0042] When a predetermined quantity of the brake fluid is stored
in the pressure control reservoir 40, the valve object 41 is seated
on the valve seat 42, such that the brake fluid cannot flow into
the pressure control reservoir 40. For this reason, brake fluid
which exceeds the suction ability of the rotary pump 10 does not
flow into the reservoir chamber 40c, so high pressure is not
impressed to the intake side of the rotary pump 10.
[0043] The rotary pump 10 is described with reference to FIGS.
2A-2C and FIG. 3. FIGS. 2A-2C correspond to the rotary pump 10 in
FIG. 1. FIG. 2A is a cross-sectional view taken along a line
IIA-IIA in FIG. 2B. FIG. 2B is cross-sectional view taken along a
line IIB-O-IIB in FIG. 2A. FIG. 2C is a cross-sectional view taken
along a line IIC-IIC in FIG. 2B.
[0044] The rotary pump 10 is a trochoid pump which is an internal
gear pump. As shown in FIGS. 2A-2C, the rotary pump 10 is arranged
in a rotor chamber 50a defined in a casing 50. An outer rotor 51
and an inner rotor 52 are contained in the rotor chamber 50a of the
casing 50. The outer rotor 51 and the inner rotor 52 are assembled
in the casing 50 in a state where respective center axes (point X
and point Y in the drawing) are shifted from each other. The outer
rotor 51 is provided at its inner periphery with an inner teeth
portion 51a. The inner rotor 52 is provided at its outer periphery
with an outer teeth portion 52a. The inner teeth portion 51a of the
outer rotor 51 and the outer teeth portion 52a of the inner rotor
52 are in mesh with each other and form a plurality of gap portions
53.
[0045] As is apparent from FIG. 2A, the rotary pump 10 is a
multiple teeth trochoid type pump having no partition plates
(crescent) in which the gap portions 53 are formed by the inner
teeth portion 51a of the outer rotor 51 and the outer teeth portion
52a of the inner rotor 52. The inner rotor 52 and the outer rotor
51 share a plurality of contact points (that is, contact faces) at
the mesh faces in order to transmit rotation torque of the inner
rotor 52 to the outer rotor 51.
[0046] As shown in FIG. 2B, the casing 50 includes a first side
plate 71, a second side plate 72 and a central plate 73, which
define the rotor chamber 50a. The outer rotor 51 and the inner
rotor 52 are arranged between the first side plate 71 and the
second side plate 72. The central plate 73 is placed between the
first side plate 71 and the second side plate 72, and has a bore in
which the outer rotor 51 and the inner rotor 52 are housed. The
central plate 73 is positioned to surround the outer periphery of
the outer rotor 51. A minute clearance S is formed between the
outer perimeter of the outer rotor 51 and the inner perimeter of
the central plate 73, and brake fluid flows into the minute
clearance S.
[0047] As shown in FIG. 2B, the first and second side plates 71 and
72 are respectively provided at their center portions with center
bores 71a and 72a which communicate with the rotor chamber 50a. A
drive shaft 54 fitted to the inner rotor 52 is housed in the center
bores 71a and 72a. The outer rotor 51 and the inner rotor 52 are
rotatably arranged in the bore of the central plate 73. That is, a
rotating unit constituted by the outer rotor 51 and the inner rotor
52 is rotatably contained in the rotor chamber 50a of the casing
50. As shown in FIG. 2A, the outer rotor 51 rotates with a point X
as a rotation axis and the inner rotor 52 rotates with a point Y as
a rotation axis.
[0048] When a line running on both the point X and the point Y
respectively corresponding to the rotation axes of the outer rotor
51 and the inner rotor 52 is defined as a center line Z of the
rotary pump 10 in the cross-section shown in FIG. 2A, an intake
port 60 and a discharge port 61 both of which communicate with the
rotor chamber 50a are formed on the left and right sides of the
center line Z in the first side plate 71. The intake port 60 and
the discharge port 61 are arranged respectively at positions
communicating with the plurality of gap portions 53. The brake
fluid from outside can be sucked into the gap portions 53 via the
intake port 60 and the brake fluid in the gap portions 53 can be
discharged to outside via the discharge port 61.
[0049] There exist a maximum gap portion 53a where the brake fluid
volume is the largest and a minimum gap portion 53b where the brake
fluid volume is the smallest among the plurality of the gap
portions 53. The maximum and minimum gap portions 53a and 53b
communicate neither with the intake port 60 nor with the discharge
port 61. The maximum and minimum gap portions 53a and 53b serve to
hold pressure difference between the intake pressure at the intake
port 60 and the discharge pressure at the discharge port 61.
[0050] As shown in FIG. 2A, the inner wall surface of the central
plate 73 is provided with a concave portion 73a and a concave
portion 73b recessed outward in the radial direction of the outer
rotor 51, at the positions advanced by about 45 degrees from the
center line Z toward the intake port 60 centering on the point X
which is the rotation axis of the outer rotor 51. A first sealing
member 80 and a second sealing member 81 are respectively installed
in the concave portions 73a and 73b to restrain the brake fluid
from flowing from the high pressure outer circumference to the low
pressure outer circumference.
[0051] The first sealing member 80 consists of a rubber component
80a which has a spherical or approximately cylinder shape, and a
resin component 80b which has a rectangular parallelepiped shape.
The resin component 80b is biased or pressed by the rubber
component 80a to be brought into contact with the outer rotor 51 so
as to seal the outer periphery of the outer rotor 51. That is, as
the dimensional deviation of the outer rotor 51 due to
manufacturing errors or the like is inevitable, the rubber
component 80a produces elastic force which can absorb the
dimensional deviation.
[0052] The resin component 80b has a width dimension in the
rotational direction of the outer rotor 51 in a manner that there
arises a clearance between the resin component 80b and the concave
portion 73a when the resin component 80b is arranged in the concave
portion 73a. If the width dimension of the resin component 80b is
made the same as the width dimension of the concave portion 73a, it
becomes difficult to come out when the resin component 80b enters
the concave portion 73a by flow of the brake fluid pressure at a
pump drive time. In the present embodiment, the resin component 80b
is made such that the brake fluid can enter the space between the
rubber component 80a and the resin component 80b. Therefore, the
resin component 80b can easily come out of the concave portion 73a
with the pressure of brake fluid. The second seal member 81 is also
equipped with a rubber component 81a and a resin component 81b.
Since the second seal member 81 has the same structure as the first
seal member 80, the explanation is omitted.
[0053] Furthermore, as shown in FIG. 2B, a seal groove part 71b is
defined in the first side plate 71. The seal groove part 71b has a
circular shape (frame shape) surrounding the drive shaft 54, as
shown by the single chain line in FIG. 2A. Further, the groove
width of the seal groove part 71b is made large in a predetermined
domain, and the seal groove part 71b is made to communicate with
the discharge port 61.
[0054] The center of the seal groove part 71b is positioned
eccentrically on a side of the intake port 60 (on a left side of
the drawing) with respect to the axial center of the drive shaft
54. The seal groove part 71b passes through a portion between the
discharge port 61 and the drive shaft 54, the maximum and minimum
gap portions 53a and 53b, and a portion where the first and second
seal members 80 and 81 seal the outer circumference gap outside the
outer rotor 51.
[0055] A seal component 100 is arranged in the seal groove part
71b. The seal component 100 has an elastic component 100a made of
elastic body such as rubber, and a resin component 100b made of
resin. The resin component 100b is pressed toward the outer rotor
51 and the inner rotor 52 by the elastic component 100a.
[0056] The resin component 100b has a circular shape similar to the
shape of the seal groove part 71b. The resin component 100b has a
base part 100c and a convex part 100d projected from the base part
100c on the end surface. The resin component 100b is arranged in a
manner that the convex part 100d is located on the open side of the
seal groove part 71b, such that the convex part 100d is in contact
with both the outer rotor 51 and the inner rotor 52 and the central
plate 73. The elastic component 100a is arranged on the bottom side
of the seal groove part 71b with respect to the resin component
100b. Therefore, the resin component 100b is pressed by the elastic
force of the elastic component 100a and the discharge pressure of
the brake fluid introduced into the seal groove part 71b, such that
the seal function is achieved.
[0057] The convex part 100d has a shape shown by the dashed-line
hatching in FIG. 2A, and has a sealing part 100e and a sealing part
100f. The sealing part 100e works while the gap portion 53 is
shifted from the state communicating with the intake port 60 to the
state communicating with the discharge port 61. The sealing part
100e has a dimension which is able to cover at least the maximum
gap portion 53a on the whole surface so as to tightly seal the
maximum gap portion 53a.
[0058] The sealing part 100f works while the gap portion 53 is
shifted from the state communicating with the discharge port 61 to
the state communicating with the intake port 60. The sealing part
100f has a dimension which is able to cover at least the minimum
gap portion 53b on the whole surface so as to tightly seal the
minimum gap portion 53b.
[0059] The seal component 100 seals the clearance between the axial
end surfaces of the outer rotor 51 and the inner rotor 52 and the
first side plate 71, between the high pressure part and the low
pressure part. Specifically, the seal component 100 seals the space
between the discharge port 61 in the high-pressure state and the
gap between the drive shaft 54 and the inner rotor 52 and the
intake port 60 in the low-pressure state.
[0060] On the other hand, the end surface of the second side plate
72 adjacent to the rotor chamber 50a is in direct contact with the
axial end surfaces of the outer rotor 51 and the inner rotor 52 so
as to achieve mechanical sealing. Due to the mechanical sealing,
the clearance between the axial end surfaces of the outer rotor 51
and the inner rotor 52 and the second side plate 72 can be sealed
between the high pressure part and the low pressure part.
Specifically, the space between the discharge port 61 in the
high-pressure state and the gap between the drive shaft 54 and the
inner rotor 52 and the intake port 60 in the low-pressure state can
be sealed by the mechanical sealing.
[0061] The seal component 100 located adjacent to the first side
plate 71 presses the outer rotor 51 and the inner rotor 52, and the
outer rotor 51 and the inner rotor 52 are pressed on the second
side plate 72, such that the mechanical sealing is achieved. At
this time, because the resin component 100b of the seal component
100 is pressed by the elastic component 100a and the discharge
pressure of the brake fluid introduced into the seal groove part
71b, the outer rotor 51 and the inner rotor 52 are pressed on the
second side plate 72 at the high pressure. For this reason, the
rotation frictional resistance between the outer rotor 51 and the
inner rotor 52, and the second side plate 72 becomes large, so the
drive torque increases in a conventional art.
[0062] According to the present disclosure, as shown in FIGS. 2B
and 2C, the second side plate 72 which receives the mechanical
sealing has an intake groove 72b which communicates with the intake
port 60 and a discharge groove 72c which communicates with the
discharge port 61. The fluid pressure is introduced from the intake
port 60 and the discharge port 61 through the intake groove 72b and
the discharge groove 72c, respectively, so as to push back the
outer rotor 51 and the inner rotor 52. Thus, the frictional
resistance is reduced by reducing the force pushing the second side
plate 72 by the outer rotor 51 and the inner rotor 52. Accordingly,
the increase in the drive torque can be restricted.
[0063] The high pressure part and the low pressure part exist on
the axial end surfaces of the outer rotor 51 and the inner rotor
52. At the high pressure part, the frictional resistance is reduced
by forming the discharge groove 72c. However, at the low pressure
part, the force pushing back the outer rotor 51 and the inner rotor
52 is not enough. Specifically, on the end surfaces of the outer
rotor 51 and the inner rotor 52, the brake fluid pressure falls
gradually from the discharge groove 72c in the high pressure state
toward the space between the drive shaft 54 and the inner rotor 52
or the intake port 60 in the low pressure state. Therefore, while
going from the discharge groove 72c to the seal components 80 and
81, especially at an area of the outer rotor 51 adjacent to the
seal component 80 and 81 relative to the center line Z, the force
which puts back the outer rotor 51 toward the seal component 100
becomes small. For this reason, the contact resistance between the
outer rotor 51 and the second side plate 72 becomes large.
[0064] According to the present embodiment, as shown in FIG. 2C,
the end surface of the second side plate 72 is equipped with a
concave portion 72d. Specifically, the concave portion 72d is
formed on the end surface of the second side plate 72 adjacent to
the maximum gap portion 53a relative to the drive shaft 45. When
the rotary pump 10 is driven, in response to the rotation of the
rotors 51 and 52, the concave portion 72d is made to communicate
with the gap portion 53. More specifically, of the end surface of
the second side plate 72, the concave portion 72d is located in an
outer teeth passing section (EXPS), which is shown with the
single-chain line in FIG. 3, between a line on which the teeth tip
of the outer teeth part 52a of the inner rotor 52 passes and a line
on which the teeth bottom of the outer teeth part 52a of the inner
rotor 52 passes.
[0065] In the present embodiment, a plurality of the concave
portions 72d are arranged in the rotational direction of the inner
rotor 52, in the outer teeth passing section. Moreover, the concave
portion 72d is located adjacent to the discharge port 61 with
respect to the center line Z. The concave portion 72d is made to
communicate with the gap portion 53 where the volume is gradually
decreased in response to the rotation of both the rotors 51 and 52,
of the plurality of the gap portions 53. The size and the shape of
the concave portion 72d are not limited, but each of the concave
portions 72d has a shape to communicate with only one gap portion
53.
[0066] For example, as shown in FIG. 4, if one concave portion 72d
simultaneously communicates with two gap portions 53 located
adjacent with each other, the compression performance is lowered in
accordance with the volume change in the gap portion 53. For this
reason, the size and the shape are set in a manner that each of the
concave portions 72d communicates with only one of the gap portions
53, such that the compression performance can be kept high.
[0067] In the present embodiment, the concave portion 72d extends
in the circumferential direction of the inner rotor 52, and the
both ends of the concave portion 72d have circular shape. The width
dimension of the concave portion 72d in the circumferential
direction, at this time, is set to be smaller than the teeth width
dimension of the inner rotor 52. Thus, each of the concave portions
72d communicates with only one gap portion 53.
[0068] Thus, the concave portion 72d is defined on the second side
plate 72, and the concave portion 72d is made to communicate with
the gap portion 53. For this reason, when the concave portion 72d
and the gap portion 53 communicate with each other, the brake fluid
contained in the gap portion 53 is supplied into the concave
portion 72d. Thereby, it becomes possible to make the brake fluid
intervene between the second side plate 72 and the inner rotor 52,
and the brake fluid functions as lubricating oil. The frictional
resistance of the contact part between the second side plate 72 and
the inner rotor 52 can be reduced. Therefore, it becomes possible
to decrease the amount of wear between the second side plate 72 and
the inner rotor 52.
[0069] Next, the operations of the brake device and the rotary pump
10 are explained.
[0070] For example, at a brake assistance time, the W/C pressure is
made larger than the M/C pressure which is generated by operation
of the brake pedal 1 by a driver, so as to increase the braking
force. In this case, the two-position valve 23 is made in the
communicating state suitably, and the differential pressure control
valve 22 is operated to produce the pressure difference.
[0071] Moreover, the motor 11 is controlled to drive the rotary
pump 10, so as to draw and discharge the brake fluid. Specifically,
when the motor 11 is driven, the inner rotor 52 is made to rotate
according to the rotation of the drive shaft 54. Further, the inner
teeth part 51a and the outer teeth part 52a mesh with each other,
such that the outer rotor 51 is rotated in the same direction. At
this time, each volume of the gap portions 53 is increased or
decreased while the outer rotor 51 and the inner rotor 52 have one
rotation. Therefore, the brake fluid is drawn from the intake port
60, and the brake fluid is discharged out toward the second conduit
A2 from the discharge port 61. The W/C pressure is increased by the
discharged brake fluid. Thus, fundamental pump operation can be
performed with the rotary pump 10, in which brake fluid is drawn
from the intake port 60 and is discharged from the discharge port
61 by the rotation of the rotors 51 and 52.
[0072] At this time, since the pressure difference control valve 22
is in condition able to generate the pressure difference, the
discharge pressure of the rotary pump 10 is applied to the
downstream side of the pressure difference control valve 22, i.e.,
each of the W/C 4 and the W/C 5, such that the W/C pressure can be
generated to be larger than the M/C pressure. For this reason, the
W/C pressure, which is larger than the M/C pressure generated by
operation of the brake pedal 1 by a driver, can be generated with
the brake device.
[0073] At this time, the outer perimeter of the outer rotor 51
adjacent to the intake port 60 is made to correspond to the intake
pressure (atmospheric pressure), due to the brake fluid drawn
through the pressure control reservoir 40, and the outer perimeter
of the outer rotor 51 adjacent to the discharge port 61 is made to
correspond to high discharge pressure.
[0074] For this reason, in the outer perimeter of the outer rotor
51, a low pressure portion and a high pressure portion arise.
However, as mentioned above, the low pressure portion and the high
pressure portion of the outer rotor 51 are separated from each
other by the seal components 80 and 81. Therefore, brake fluid can
be prevented from leaking toward the low-pressure portion adjacent
to the intake port 60 from the high-pressure portion adjacent to
the discharge port 61 through the outer perimeter of the outer
rotor 51. Moreover, due to the seal components 80 and 81, the outer
perimeter of the outer rotor 51 adjacent to the intake port 60 has
low pressure which is approximately the same as a pressure in the
gap portion 53 which communicates with the intake port 60.
Furthermore, the outer perimeter of the outer rotor 51 adjacent to
the discharge port 61 has high pressure which is approximately the
same as a pressure in the gap portion 53 which communicates with
the discharge port 61. For this reason, the pressure balance can be
maintained between inside and outside of the outer rotor 51, and
the pump can be stably driven.
[0075] The seal components 80 and 81 are located adjacent to the
intake port 60 in the rotary pump 10 of the present embodiment, so
the outer perimeter of the outer rotor 51 has a high discharge
pressure up to the position at which the maximum and minimum gap
portion 53a, 53b is surrounded. For this reason, the outer rotor 51
is pressed in the axial direction, and a load is applied in a
direction reducing the teeth tip clearance between the inner teeth
part 51 a of the outer rotor 51 and the outer teeth part 52a of the
inner rotor 52, at the maximum gap portion 53a. Thereby, the brake
fluid leak generated through the teeth tip clearance can be
reduced.
[0076] On the other hand, a clearance between the axial end surface
of the inner rotor 52 and the outer rotor 51 and the side plate 71,
72 also has a low pressure portion and a high pressure portion, due
to the intake port 60 in the low pressure state, the gap between
the drive shaft 54 and the inner rotor 52, and the discharge port
61 in the high pressure state. However, the low pressure portion
and the high pressure portion are sealed from each other by the
seal component 100 or the mechanical sealing, so brake fluid leak
does not occur toward the low pressure portion from the high
pressure portion. Moreover, the seal component 100 is formed to
overlap the seal components 80 and 81, and the mechanical sealing
is formed to be close with the seal components 80 and 81, so brake
fluid leak does not occur either.
[0077] Since the concave portion 72d is formed in the end surface
of the second side plate 72, when the concave portion 72d and the
gap portion 53 communicate with each other, the brake fluid
contained in the gap portion 53 is supplied into the concave
portion 72d. Thereby, it becomes possible to make the brake fluid
intervene between the second side plate 72 and the inner rotor 52.
The brake fluid functions as lubricating oil, and the frictional
resistance of the contact part between the second side plate 72 and
the inner rotor 52 can be reduced. Therefore, it becomes possible
to decrease the amount of wear between the second side plate 72 and
the inner rotor 52.
[0078] Furthermore, the concave portion 72d is located adjacent to
the discharge port 61 relative to the center line Z, so it becomes
possible to make the concave portion 72d to communicate with the
gap portion 53 in which the volume is decreased, of the plural gap
portions 53. For this reason, high pressure brake fluid can be
supplied in the concave portion 72d, and the inner rotor 52 can be
pressed back toward the seal component 100 with the high pressure.
Therefore, the frictional resistance of the contact part between
the second side plate 72 and the inner rotor 52 can be reduced
more, and it becomes possible to further decrease the amount of
wear between the second side plate 72 and the inner rotor 52.
[0079] If the minute clearance S is made to communicate with the
concave portion 72d, high pressure brake fluid is supplied from the
minute clearance S into the concave portion 72d, so the brake fluid
pressure of the concave portion 72d may be made higher. However,
when the concave portion 72d communicates with the gap portion 53
under performing the compression, the volume adjacent to the
discharge groove 72c turns into dead volume, and the compression
efficiency falls sharply. For this reason, the concave portion 73d
is made to communicate with only the gap portion 53 without
communicating with the minute clearance S.
(Second Embodiment)
[0080] In a second embodiment, the frictional resistance is reduced
between the second side plate 72 and the outer rotor 51.
[0081] As shown in FIG. 5, the end surface of the second side plate
72 is equipped with a concave portion 72e. Specifically, of the end
surface of the second side plate 72, the concave portion 72e is
located adjacent to the maximum gap portion 53a where the volume
becomes the largest relative to the drive shaft 54. When the rotary
pump 10 is driven, the concave portion 72e is made to communicate
with the gap portion 53 in response to rotation of the rotors 51
and 52. More specifically, the concave portion 72e is located in an
inner teeth passing section (INPS), shown in the single-chain line
in FIG. 6, which is defined between a line on which the teeth tip
of the inner teeth part 51a of the outer rotor 51 passes and a line
on which the teeth bottom of the inner teeth part 51a of the outer
rotor 51 passes.
[0082] In the inner teeth passing section, a plurality of the
concave portions 72e are arranged in the circumferential direction
of the outer rotor 51. Moreover, the concave portion 72e is located
adjacent to the discharge port 61 relative to the center line Z.
The concave portion 72e is made to communicate with the gap portion
53 where the volume is decreased gradually in response to the
rotation of both the rotors 51 and 52, of the plurality of the gap
portions 53. Similarly to the concave portion 72d of the first
embodiment, the size and the shape of the concave portion 72e are
not limited under the condition that each of the concave portions
72e communicates with only one gap portion 53.
[0083] The concave portion 72e is shaped to extend along the
circumferential direction of the outer rotor 51e, and both ends of
the concave portion 72e are made circular. The width dimension of
the concave portion 72e in the circumferential direction, at this
time, is made to be smaller than the teeth width of the outer rotor
51. Thereby, each of the concave portions 72e communicates with
only one gap portion 53.
[0084] Thus, the concave portion 72e is defined in the second side
plate 72, and the concave portion 72e is made to communicate with
the gap portion 53. For this reason, when the concave portion 72e
and the gap portion 53 communicate with each other, the brake fluid
contained in the gap portion 53 is supplied in the concave portion
72e. Thereby, it becomes possible to make the brake fluid intervene
between the second side plate 72 and the outer rotor 51, and the
brake fluid functions as lubricating oil. The frictional resistance
of the contact part between the second side plate 72 and the outer
rotor 51 can be reduced. Therefore, it becomes possible to decrease
the amount of wear between the second side plate 72 and the outer
rotor 51.
[0085] As explained above, the concave portion 72e is formed in the
inner teeth passing section of the second side plate 72 through
which the inner teeth part 51a of the outer rotor 51 passes.
(Third Embodiment)
[0086] In a third embodiment, the frictional resistance is reduced
between the second side plate 72, and the outer rotor 51 and the
inner rotor 52.
[0087] As shown in FIG. 7, the end surface of the second side plate
72 is equipped with a concave portion 72f. Specifically, the
concave portion 72f is located adjacent to the minimum gap portion
53b where the volume becomes the minimum relative to the drive
shaft 54. The concave portion 72f is formed in an overlap area
where the inner teeth passing section and the outer teeth passing
section overlap with each other. For this reason, when the rotary
pump 10 is driven, the concave portion 72f is made to the
communicate with either of the plurality of the gap portions 53 in
response to the rotation of both the rotors 51 and 52.
[0088] A plurality of the concave portions 72f are arranged in the
circumferential direction of the outer rotor 51 and the inner rotor
52. Moreover, the concave portion 72f is located adjacent to the
discharge port 61 with respect to the center line Z. The concave
portion 72f is formed to communicate with the gap portion 53 where
the volume is gradually decreased in response to the rotation of
both the rotors 51 and 52, of the plurality of the gap portions 53.
Similarly to the concave portion 72d of the first embodiment, the
shape and the size of the concave portion 72f is not limited under
the condition where each of the concave portions 72f communicates
with only one gap portion 53.
[0089] The concave portion 72f is formed to extend in the
circumferential direction of the outer rotor 51 and the inner rotor
52, and both ends of the concave portion 72f are made circular. The
width dimension of the concave portion 72f in the circumferential
direction is made to become smaller than the teeth width of the
outer rotor 51 and the inner rotor 52. Thereby, each of the concave
portions 72f communicates with only one gap portion 53.
[0090] Thus, the concave portion 72f is defined in the second side
plate 72, and the concave portion 72f is made to communicate with
the gap portion 53. For this reason, when the concave portion 72f
and the gap portion 53 communicate with each other, the brake fluid
contained in the gap portion 53 is supplied into the concave
portion 72f. Thereby, it becomes possible to make the brake fluid
intervene between the second side plate 72, and the outer rotor 51
and the inner rotor 52. The brake fluid functions as lubricating
oil. The frictional resistance of the contact part between the
second side plate 72, and the outer rotor 51 and the inner rotor 52
can be reduced. Therefore, it becomes possible to decrease the
amount of wear between the second side plate 72, and the outer
rotor 51 and the inner rotor 52.
[0091] The concave portion 72f is formed adjacent to the minimum
gap portion 53b where the volume becomes the minimum, in the
overlap area in which the outer teeth passing section and the inner
teeth passing section overlap with each other.
(Other Embodiment)
[0092] The shape of the concave portion 72d-72f is not limited to
the above description, and may be circular, ellipse, oval, or
rectangle. The number of the concave portions 72d-72f is not
limited. The first embodiment to the third embodiment may be
suitably combined with each other to provide a mixture of the
concave portions 72d-72f. The concave portions 72d-72f may be
located adjacent to the intake port 60 relative to the center line
Z, both sides of the center line Z, or on the center line Z.
[0093] If the concave portions 72d-72f are formed adjacent to the
intake port 60 relative to the center line Z, the brake fluid
supplied to the concave portion 72d-72f may not have high pressure.
In this case, the brake fluid functions as lubricating oil, while
it may be impossible to press back the outer rotor 51 and the inner
rotor 52 toward the seal component 100 with the brake fluid
pressure in the concave portion 72d-72f.
[0094] The casing 50 includes the first side plate 71 in the above
embodiment. Alternatively, in a case where components of the rotary
pump 10 are accommodated in a housing for an actuator which
controls the brake fluid pressure, the housing may constitute the
first side plate 71.
[0095] The concave portion 72d is formed in the outer teeth passing
section in the first embodiment. However, a part of the concave
portion 72d may be located outside the line on which the teeth
bottom of the outer teeth part 52a passes.
[0096] The concave portion 72e is formed in the inner teeth passing
section in the second embodiment. However, a part of the concave
portion 72e may be located outside the line on which the teeth
bottom of the inner teeth part 51a passes.
[0097] Such changes and modifications are to be understood as being
within the scope of the present disclosure as defined by the
appended claims.
* * * * *