U.S. patent application number 15/259979 was filed with the patent office on 2017-03-16 for vehicle hydraulic device.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. The applicant listed for this patent is AISIN AW CO., LTD., TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Toshiaki HAYASHI, Yoshimitsu HYODO, Takafumi INAGAKI, Yoshihiro MIZUNO, Shuji MORIYAMA, Hiromitsu NITANI, Yoshinobu SOGA, Mitsuhiro TAKEDA.
Application Number | 20170074262 15/259979 |
Document ID | / |
Family ID | 58257321 |
Filed Date | 2017-03-16 |
United States Patent
Application |
20170074262 |
Kind Code |
A1 |
MIZUNO; Yoshihiro ; et
al. |
March 16, 2017 |
VEHICLE HYDRAULIC DEVICE
Abstract
A vehicle hydraulic device is provided with an electric
motor-driven oil pump and a shuttle valve, so that a vane pump
operates smoothly, even at the start, with a backpressure applied
from the electric motor-driven oil pump to the vanes. Even when the
oil pressure of a working fluid discharged from the vane pump
exceeds the backpressure inside vane housing grooves, the working
fluid flows from a vane pump discharge oil passage to a
backpressure oil passage, so that the vanes are not pushed into the
housing grooves. Thus, it is possible to reduce the fluctuations in
discharge amount of the vane pump due to fluctuations in oil
pressure of the vane pump discharge oil passage during operation of
the vane pump.
Inventors: |
MIZUNO; Yoshihiro;
(Nagoya-shi, JP) ; SOGA; Yoshinobu; (Toyota-shi,
JP) ; MORIYAMA; Shuji; (Nagakute-shi, JP) ;
INAGAKI; Takafumi; (Toyota-shi, JP) ; NITANI;
Hiromitsu; (Nagakute-shi, JP) ; TAKEDA;
Mitsuhiro; (Anjo-shi, JP) ; HAYASHI; Toshiaki;
(Anjo-shi, JP) ; HYODO; Yoshimitsu; (Anjo-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOYOTA JIDOSHA KABUSHIKI KAISHA
AISIN AW CO., LTD. |
Toyota-shi
Anjo-shi |
|
JP
JP |
|
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
AISIN AW CO., LTD.
Anjo-shi
JP
|
Family ID: |
58257321 |
Appl. No.: |
15/259979 |
Filed: |
September 8, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 2270/585 20130101;
F04C 2270/185 20130101; F04C 14/06 20130101; F04C 2210/206
20130101; F04C 14/24 20130101; F04C 2/3446 20130101; F01C 21/0863
20130101 |
International
Class: |
F04C 14/06 20060101
F04C014/06; F04C 14/02 20060101 F04C014/02; F04C 14/24 20060101
F04C014/24; F04C 2/344 20060101 F04C002/344 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 14, 2015 |
JP |
2015-181242 |
Claims
1. A vehicle hydraulic device comprising: a vane pump that is
driven to rotate by an engine, and the vane pump including a pump
housing, a plurality of vanes, and a rotor, the pump housing having
an inner peripheral cam surface with an elliptical sectional shape,
the plurality of vanes being provided inside the pump housing, the
rotor providing vane housing grooves that house the plurality of
vanes so as to be movable in a radial direction of the rotor; an
oil pressure control circuit including a first discharge oil
passage, a second discharge oil passage, and a backpressure oil
passage, the first discharge oil passage being configured to
introduce a working fluid discharged from the vane pump to a device
other than the vehicle hydraulic device, the backpressure oil
passage being configured to supply a backpressure to the plurality
of vanes inside the vane housing grooves; an electric motor-driven
oil pump configured to discharge the working fluid through the
second discharge oil passage to the backpressure oil passage; and a
shuttle valve provided at a junction of the first discharge oil
passage, the second discharge oil passage, and the backpressure oil
passage, the shuttle valve being configured to: (i) allow the
working fluid to flow from the first discharge oil passage to the
backpressure oil passage when the oil pressure of the working fluid
in the first discharge oil passage discharged from the vane pump is
higher than the oil pressure of the working fluid in the second
discharge oil passage discharged from the electric motor-driven oil
pump, and (ii) allow the working fluid to flow from the electric
motor-driven oil pump to the backpressure oil passage when the oil
pressure of the working fluid in the first discharge oil passage
discharged from the vane pump is equal to or lower than the oil
pressure of the working fluid in the second discharge oil passage
discharged from the electric motor-driven oil pump.
2. The vehicle hydraulic device according to claim 1, wherein the
electric motor-driven oil pump is configured to actuate, only at a
start of the engine and when a temperature of the working fluid is
equal to or lower than a predetermined temperature.
3. The vehicle hydraulic device according to claim 1, wherein the
oil pressure of the working fluid discharged from the electric
motor-driven oil pump decreases as a temperature of the working
fluid rises.
4. The vehicle hydraulic device according to claim 1, wherein the
electric motor-driven oil pump does not start when the time taken
for the engine to restart after stopping of the engine is within a
predetermined time.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to Japanese Patent
Application No. 2015-181242 filed on Sep. 14, 2015, the entire
contents of which are hereby incorporated by reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The present disclosure relates to a vehicle hydraulic device
having a vane pump as the oil pressure source, and more
particularly to a vehicle hydraulic device that operates smoothly
even at the start and is little affected by fluctuations in oil
pressure of a discharge oil passage during operation of the vane
pump.
[0004] 2. Description of Related Art
[0005] A vane pump driven by an engine has, inside a pump housing
with a substantially elliptical inner peripheral cam surface, for
example, a plurality of variable-displacement pump chambers that
are defined by a rotor fitted on a rotating shaft and a plurality
of vanes radially fitted into vane housing groves provided in the
rotor. As the vanes rotate while being pressed against the inner
peripheral surface of the pump housing, the volumes of the pump
chambers vary and a discharge force is applied to a working
fluid.
[0006] The force for pressing the vanes against the inner
peripheral surface of the pump housing is derived from a rotational
centrifugal force and a backpressure that presses the vanes against
the inner peripheral surface of the pump housing inside the rotor.
The working fluid discharged from the vane pump is used to obtain
this backpressure. However, if the rotation speed of the rotor is
low at the start of the vane pump, the pump may fail to start
smoothly. This is because, even when the centrifugal force of the
rotating vanes and the backpressure generated by the working fluid
discharged from the vane pump are combined, the force that presses
the vanes against the inner peripheral surface of the pump housing
is too small.
[0007] To address this problem, Japanese Patent Application
Publication No. 2008-286108 discloses a technique for raising the
backpressure inside a vane pump at the start of the vane pump.
Specifically, the oil pressure of a working fluid discharged from
an electric motor-driven oil pump is supplied through a
backpressure oil passage into vane housing grooves provided inside
the rotor, so that a plurality of vanes that are radially fitted
into the vane housing grooves formed in the rotor are pressed
against the inner peripheral surface of a pump housing. Thus, the
proposed vane pump operates smoothly even at the start.
[0008] In the vane pump of JP 2008-286108 A, if the discharge
pressure of the vane pump exceeds the backpressure inside the vane
housing grooves, the vanes may be pushed into the housing grooves
and the pressure of the working fluid discharged from the vane pump
may decrease.
SUMMARY
[0009] Having been devised in the context of these circumstances,
the present disclosure provides a vehicle hydraulic device having a
vane pump of which pump chambers vary in volume to apply a
discharge force to a working fluid as vanes rotate while being
pressed against the inner peripheral surface of a pump housing. The
vehicle hydraulic device according to the present disclosure
operates smoothly even at the start and is little affected by
fluctuations in oil pressure of the discharge oil passage during
operation of the vane pump.
[0010] According to one aspect of the present disclosure, a vehicle
hydraulic device including a vane pump, an oil pressure control
circuit, an electric motor-driven oil pump, and a shuttle valve, is
provided. The vane pump is driven to rotate by an engine. The vane
pump includes a pump housing, a plurality of vanes, and a rotor.
The pump housing has an inner peripheral cam surface with an
elliptical sectional shape. The plurality of vanes are provided
inside the pump housing. The rotor provides vane housing grooves
that house the plurality of vanes so as to be movable in a radial
direction of the rotor. The oil pressure control circuit includes a
first discharge oil passage, a second discharge oil passage, and a
backpressure oil passage. The first discharge oil passage is
configured to introduce a working fluid discharged from the vane
pump to a device other than the vehicle hydraulic device. The
backpressure oil passage is configured to supply a backpressure to
the plurality of vanes inside the vane housing grooves. The
electric motor-driven oil pump is configured to discharge the
working fluid through the second discharge oil passage to the
backpressure oil passage. The shuttle valve is provided at a
junction of the first discharge oil passage, the second discharge
oil passage, and the backpressure oil passage. The shuttle valve is
configured to: (i) allow the working fluid to flow from the first
discharge oil passage to the backpressure oil passage when the oil
pressure of the working fluid in the first discharge oil passage
discharged from the vane pump is higher than the oil pressure of
the working fluid in the second discharge oil passage discharged
from the electric motor-driven oil pump, and (ii) allow the working
fluid to flow from the electric motor-driven oil pump to the
backpressure oil passage when the oil pressure of the working fluid
in the first discharge oil passage discharged from the vane pump is
equal to or lower than the oil pressure of the working fluid in the
second discharge oil passage discharged from the electric
motor-driven oil pump.
[0011] According to the oil pressure control circuit as described
above, the vane pump operates smoothly, even at the start of the
vane pump, with a backpressure applied to the plurality of vanes by
the electric motor-driven oil pump. Moreover, even when the oil
pressure in the first discharge oil passage fluctuates to a higher
pressure during operation of the vane pump, the oil pressure in the
first discharge oil passage is supplied by the shuttle valve as the
backpressure for the vanes, and the vanes are pushed into the
housing grooves. Thus, it is possible to suppress a decrease in
pressure of the working fluid discharged from the vane pump and
realize stable operation.
[0012] In the vehicle hydraulic device, the electric motor-driven
oil pump may be configured to actuate only at a start of the engine
and when a temperature of the working fluid is equal to or lower
than a predetermined temperature.
[0013] According to the oil pressure control circuit as described
above, the electric motor-driven oil pump is operated only at the
start of the engine and when the temperature of the working fluid
is equal to or lower than a predetermined temperature. Using the
electric motor-driven oil pump thus only when necessary can reduce
the usage of electric power.
[0014] Moreover, in the vehicle hydraulic device, the oil pressure
of the working fluid discharged from the electric motor-driven oil
pump may decrease as a temperature of the working fluid rises.
[0015] According to the oil pressure control circuit as described
above, the oil pressure of the working fluid discharged from the
electric motor-driven oil pump decreases as the temperature of the
working fluid rises. Thus, the usage of electric power can be
further reduced.
[0016] Furthermore, in the vehicle hydraulic device, the electric
motor-driven oil pump may not start when a time taken for the
engine to restart after stopping of the engine is within a
predetermined time.
[0017] According to the oil pressure control circuit as described
above, it is possible to reduce the electric power consumption by
preventing the actuation of the electric motor-driven oil pump when
the time taken for the engine to restart after stopping is a short
time within a predetermined time, since in that case the
backpressure is not always reduced so much and then there is no
need to actuate the electric motor-driven oil pump.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Features, advantages, and technical and industrial
significance of exemplary embodiments of the disclosure will be
described below with reference to the accompanying drawings, in
which like numerals denote like elements, and wherein:
[0019] FIG. 1 is a schematic view illustrating the configuration of
the major part of a vehicle hydraulic device of a first embodiment
of the present disclosure;
[0020] FIG. 2 is a front view of a vane pump of the vehicle
hydraulic device of FIG. 1, with a cover thereof removed;
[0021] FIG. 3 is a schematic view illustrating the configuration of
the major part of a vehicle hydraulic device of a second embodiment
of the present disclosure;
[0022] FIG. 4 is a functional block diagram illustrating the major
part of an electric motor control function of an electronic
controller of FIG. 3;
[0023] FIG. 5 is a flowchart illustrating the major part of the
operation of controlling an electric motor-driven oil pump of the
vehicle hydraulic device of FIG. 3, i.e., illustrating the control
operation for reducing the electric power used by the vehicle
hydraulic device; and
[0024] FIG. 6 is a one example of a relational map used for
obtaining the required rotation speed of the electric motor-driven
oil pump according to the temperature of a working fluid of the
vehicle hydraulic device of the second embodiment.
DETAILED DESCRIPTION OF EMBODIMENTS
[0025] In the following, a first embodiment of a vehicle hydraulic
device of the present disclosure will be described in detail with
reference to the drawings.
[0026] FIG. 1 is a schematic view illustrating the configuration of
a vehicle hydraulic device 10. The vehicle hydraulic device 10
includes a vane pump 14, an electric motor-driven oil pump 48, and
a shuttle valve 50. The vane pump 14 supplies a working fluid to an
oil pressure control device 12 that functions as an oil pressure
control circuit. The oil pressure control device 12 consumes the
working fluid of, for example, a hydraulic cylinder, such as the
sheave of an automatic transmission (A/T) or a continuously
variable transmission (CVT). The electric motor-driven oil pump 48
supplies a backpressure to the vane pump 14.
[0027] The vane pump 14 is driven by the rotation of an engine 15.
The vane pump 14 has a first suction port 22, a second suction port
24, a first discharge port 26, and a second discharge port 28. The
first suction port 22 and the second suction port 24 are ports
through which the working fluid stored in an oil pan 18 is
suctioned via an oil strainer 20. The first discharge port 26 and
the second discharge port 28 are ports through which the suctioned
working fluid is discharged to the outside of the pump. The vane
pump 14 further has a first backpressure groove 42 and a second
backpressure groove 44 that supply a backpressure to a plurality of
vanes 82 that suction and discharge the working fluid. The working
fluid is sent from the suction ports 22, 24 to the discharge ports
26, 28 through pump chambers P provided by the vanes 82.
[0028] A vane pump discharge oil passage 30, corresponding to the
first discharge oil passage, is connected to the first discharge
port 26 and the second discharge port 28, and the vane pump
discharge oil passage 30 serves as a working fluid supply passage
to the oil pressure control device 12 through which the working
fluid discharged from the first discharge port 26 and the second
discharge port 28 is pumped to the oil pressure control device 12.
The vane pump discharge oil passage 30 is also connected to a first
input port 50a of the shuttle valve 50, and serves as a working
fluid supply passage to the vane pump 14 through which the working
fluid discharged from the first discharge port 26 and the second
discharge port 28 is pumped to the first backpressure groove 42 and
the second backpressure groove 44. An electric motor-driven oil
pump discharge oil passage 31, corresponding to the second
discharge oil passage, is connected to the other, second input port
50b of the shuttle valve 50, and an output port 50c of the shuttle
valve 50 is connected to a backpressure oil passage 36.
[0029] A suction oil passage 34 connects the first suction port 22
and the second suction port 24 of the vane pump 14 to the oil pan
18 via the oil strainer 20 such that the working fluid stored in
the oil pan 18 is suctioned to the first suction port 22 and the
second suction port 24. The suction oil passage 34 also connects
the electric motor-driven oil pump 48 to the oil pan 18 via the oil
strainer 20 such that the working fluid stored in the oil pan 18 is
suctioned to the electric motor-driven oil pump 48. A return oil
passage 32 returns the working fluid of the oil pressure control
device 12 to the suction oil passage 34 of the vane pump 14.
[0030] FIG. 2 is a front view of the vane pump 14 of the vehicle
hydraulic device 10, with a pump cover thereof removed. The vane
pump 14 is composed of a body 68, a cam ring 70, a side plate 66, a
rotor 74, a pump shaft 76, and the pump cover (not shown). The body
68 is provided with a substantially columnar recess 16. The cam
ring 70 has a substantially cylindrical shape, and is fitted inside
the recess 16 so as to be unable to rotate relative to the body 68.
The cam ring 70 corresponds to the pump housing, and is therefore
also called the pump housing. The side plate 66 has a disc shape,
and is mounted so as to be interposed between a bottom wall surface
of the recess 16 of the body 68 and the cam ring 70, with one flat
surface and the other flat surface of the side plate 66 in contact
with the bottom wall surface of the recess 16 and a substantially
circular one end surface of the cam ring 70, respectively. The
rotor 74 has a columnar shape, and is housed such that the outer
peripheral surface faces an inner peripheral cam surface 78 of the
cam ring 70 with a small space therebetween and that one end
surface in the direction of a rotational axis can come into sliding
contact with the other flat surface of the side plate 66. The pump
shaft 76 is fixed to the rotor 74 coaxially with the rotational
axis of the rotor 74, is rotatably supported on the body 68, and
rotates the rotor 74 in the direction of the arrow indicated in
FIG. 2, i.e., in the clockwise direction, according to the driving
of a driving source, such as the engine 15. The pump cover is
fastened to the body 68 so as to cover the opening of the recess 16
while being in contact with the substantially circular other end
surface of the cam ring 70 and able to come into sliding contact
with the other end surface of the rotor 74 in the axial
direction.
[0031] The cam ring 70 has the inner peripheral cam surface 78 that
is the inner peripheral surface with a substantially elliptical
sectional shape. The rotor 74 includes slits 80, corresponding to
the plurality of vane housing grooves, that are formed over the
entire axial length of the outer peripheral surface, radially from
a center part in the radial direction toward the outer peripheral
surface at regular intervals in the circumferential direction, and
the plurality of rectangular, plate-shaped vanes 82 that are fitted
into the slits 80. Since the slits 80 house the vanes, the slits 80
are also called vane housing grooves. The vane 82 is inserted into
the slit 80 such that the side surfaces of the vane 82 in the
circumferential direction of the rotor 74 can slide in the radial
direction of the rotor 74 over inner walls of the slit 80 facing
the vane 82; that the side surfaces of the vane 82 in the axial
direction come into sliding contact with the other end surface of
the side plate 66 and an inner wall surface of the pump cover,
respectively; and that the radially outer end surface of the vane
82 can slide over the inner peripheral cam surface 78 of the cam
ring 70.
[0032] When the rotor 74 is driven to rotate, the vane 82 is pushed
out toward the radially outer side of the rotor 74 from the inner
wall of the slit 80 under the backpressure from the first
backpressure groove 42 and the second backpressure groove 44, so
that the radially outer end surface of the vane 82 is pressed
against the inner peripheral cam surface 78 of the cam ring 70 and,
in this state, slides over the inner peripheral cam surface 78 in
the rotation direction of the rotor 74. Thus, the plurality of pump
chambers P are defined by the side surfaces of the adjacent vanes
82 facing each other in the circumferential direction, the inner
peripheral cam surface 78, the outer peripheral surface of the
rotor 74, the other end surface of the side plate 66, and the inner
wall surface of the pump cover. Since the inner peripheral cam
surface 78 has a substantially elliptical shape, as the rotor 74
makes one rotation, the vane 82 reciprocates twice inside the slit
80 in the radial direction of the rotor 74, so that the volume of
the pump chamber P increases and decreases twice.
[0033] In the side plate 66 and the body 68, the pair of first
suction port 22 and second suction port 24 communicating with the
pump chambers P, which increase in volume according to the rotation
of the rotor 74, are formed across the pump shaft 76 so as to
straddle both the side plate 66 and the body 68. In the side plate
66 and the body 68, the pair of first discharge port 26 and second
discharge port 28 communicating with the pump chambers P, which
decrease in volume according to the rotation of the rotor 74, are
formed across the pump shaft 76 so as to straddle both the side
plate 66 and the body 68. The first discharge port 26 is located on
the front side in the rotation direction of the rotor 74 relative
to the first suction port 22. The second discharge port 28 is
located on the front side in the rotation direction of the rotor 74
relative to the second suction port 24. It is also possible to form
the ports 22, 24, 26, 28 only in the side plate 66, instead of
forming these ports so as to straddle both the side plate 66 and
the body 68.
[0034] The side plate 66 communicates with the inner peripheral
ends of the slits 80, into which the vanes 82 defining the pump
chambers P are fitted, between the first suction port 22 and the
first discharge port 26. The first backpressure groove 42 and the
second backpressure groove 44 that supply a backpressure for
pressing the vanes 82 against the inner peripheral cam surface 78
are formed in a semi-annular shape in the circumferential direction
of the rotor 74. The first backpressure groove 42 and the second
backpressure groove 44 communicate with the backpressure oil
passage 36.
[0035] When the vane pump 14 is started according to the driving of
the engine 15 and the rotor 74 is rotated in the clockwise
direction in FIG. 2, the working fluid inside the oil pan 18 is
suctioned through the suction oil passage 34 into the first suction
port 22 and the second suction port 24, and carried to each pump
chamber P of the vane pump 14 of which the volume increases
gradually as the rotor 74 rotates. As the rotor 74 rotates and the
volumes of the pump chambers P decrease accordingly, the working
fluid suctioned into the pump chambers P is discharged through the
first discharge port 26 and the second discharge port 28 to the
vane pump discharge oil passage 30. When an electric motor 52
dedicated to the electric motor-driven oil pump 48 is driven along
with the start of the engine 15 and the electric motor-driven oil
pump 48 is started accordingly, the working fluid inside the oil
pan 18 is suctioned through the suction oil passage 34 into the
electric motor-driven oil pump 48, and discharged to the electric
motor-driven oil pump discharge oil passage 31 communicating with
the second input port 50b of the shuttle valve 50.
[0036] The vane pump discharge oil passage 30 and the electric
motor-driven oil pump discharge oil passage 31 communicate
respectively with the first input port 50a and the second input
port 50b of the shuttle valve 50. The backpressure oil passage 36
communicates with the output port 50c of the shuttle valve 50. When
the oil pressure of the working fluid in the vane pump discharge
oil passage 30 discharged from the vane pump 14 is higher than the
oil pressure of the working fluid in the electric motor-driven oil
pump discharge oil passage 31 discharged from the electric
motor-driven oil pump 48, the shuttle valve 50 allows the working
fluid to flow from the vane pump discharge oil passage 30 to the
backpressure oil passage 36. When the oil pressure of the working
fluid in the vane pump discharge oil passage 30 discharged from the
vane pump 14 is equal to or lower than the oil pressure of the
working fluid in the electric motor-driven oil pump discharge oil
passage 31 discharged from the electric motor-driven oil pump 48,
the shuttle valve 50 allows the working fluid to flow from the
electric motor-driven oil pump discharge oil passage 31 to the
backpressure oil passage 36. Thus, the backpressure for pressing
the vanes 82 defining the pump chambers P of the vane pump 14
against the inner peripheral cam surface 78 of the cam ring 70 is
maintained.
[0037] Thus, the vehicle hydraulic device 10 of this embodiment is
provided with the electric motor-driven oil pump 48 and the shuttle
valve 50, so that the vehicle hydraulic device operates smoothly,
even at the start, as a backpressure is applied from the electric
motor-driven oil pump 48 to the vanes 82. Moreover, even when the
oil pressure of the working fluid discharged from the vane pump
exceeds the backpressure inside the slits 80 during operation of
the vane pump 14, the working fluid flows from the vane pump
discharge oil passage 30 to the backpressure oil passage 36, so
that the vanes 82 are pushed into the slits 80 and the pressure of
the working fluid discharged from the vane pump 14 does not
decrease. Thus, it is possible to suppress the decrease in
discharge amount of the vane pump 14 even if the oil pressure in
the vane pump discharge oil passage 30 fluctuates to a higher
pressure during operation of the vane pump 14.
EMBODIMENT 2
[0038] Next, a second embodiment of the present disclosure will be
described. In the following second embodiment, those parts that
have substantially the same functions as in the first embodiment
will be denoted by the same reference signs and the detailed
description thereof will be omitted. A vehicle hydraulic device 100
of the second embodiment is different from the vehicle hydraulic
device 10 of the first embodiment in that the electric motor-driven
oil pump 48 is operated only at the start of the engine 15 and when
the temperature of the working fluid is equal to or lower than a
predetermined temperature, and in that the oil pressure of the
working fluid discharged from the electric motor-driven oil pump 48
is reduced as the temperature of the working fluid rises. Only
these differences will be described in detail below using FIG. 3 to
FIG. 6.
[0039] FIG. 3 is a schematic view illustrating the configuration of
the vehicle hydraulic device 100 of the second embodiment of the
present disclosure. The configuration of the vehicle hydraulic
device 100 is the same as the configuration of the vehicle
hydraulic device 10 shown in FIG. 1, i.e., includes the electric
motor 52, which drives the electric motor-driven oil pump 48, in
addition to the vane pump 14 that supplies the working fluid to the
oil pressure control device 12 that consumes the working fluid of,
for example, a hydraulic cylinder, such as the sheave of an A/T or
a CVT, the electric motor-driven oil pump 48 that supplies a
backpressure to the slits 80 of the vane pump 14, the shuttle valve
50, the oil pan 18, the oil strainer 20, and the oil passages for
the working fluid to flow through. However, the vehicle hydraulic
device 100 is different from the vehicle hydraulic device 10 in
that a temperature sensor 54 that detects the temperature of the
working fluid, and an electronic controller 56 that controls the
electric motor 52 on the basis of the temperature detected by the
temperature sensor 54 are provided. The electric motor 52 is driven
through a control signal from the electronic controller 56 and
actuates the electric motor-driven oil pump 48 to supply the
working fluid to the electric motor-driven oil pump discharge oil
passage 31. The electronic controller 56 is configured with a
so-called microcomputer that includes, for example, a CPU, a RAM, a
ROM, and an input-output interface, and the CPU executes output
control of the engine 15, speed change control of an automatic
transmission (not shown), etc. by processing signals according to a
program that is stored in the ROM in advance using the temporary
storage function of the RAM.
[0040] In the vehicle hydraulic device 100 of this embodiment, to
reduce the electric power used for actuating the electric
motor-driven oil pump 48, for example, the electric motor 52 is
driven only at the start of the engine 15 and when the temperature
of the working fluid is equal to or lower than a preset
temperature, so as to restrict the actuation of the electric
motor-driven oil pump 48. Moreover, to reduce the electric power
used for actuating the electric motor-driven oil pump 48, for
example, the oil pressure of the working fluid discharged from the
electric motor-driven oil pump 48 is reduced as the temperature of
the working fluid rises.
[0041] FIG. 4 is a functional block diagram illustrating the major
part of an electric motor control function of the electronic
controller 56, and including an engine start determination unit 62,
a working fluid temperature determination unit 60, and an electric
motor control unit 58. The engine start determination unit 62
determines whether or not the engine 15 is at start. The working
fluid temperature determination unit 60 determines whether or not a
working fluid temperature TOIL is equal to or lower than a preset
working fluid criterion temperature Te. The electric motor control
unit 58 actuates the electric motor 52 by sending an electric motor
control signal SM to the electric motor 52 on the basis of the
determination of the engine start determination unit 62 and the
working fluid temperature determination unit 60. The engine start
determination unit 62 may determine whether or not the time from
when the engine 15 is driven and stopped last time until the engine
15 is driven this time, i.e., the time taken to restart, is within
a predetermined time, and the electric motor control unit 58 may
control so as not to start the electric motor 52 if the time taken
to restart is within the predetermined time.
[0042] FIG. 5 is a flowchart of the major part of the operation of
controlling the electric motor-driven oil pump 48 performed by the
electronic controller 56 of FIG. 3, i.e., the control operation for
reducing the electric power used by the vehicle hydraulic device
100. This operation is executed repeatedly.
[0043] In FIG. 5, in step (hereinafter "step" will be omitted) S1
corresponding to the engine start determination unit 62, it is
determined whether or not the engine 15 is at start. The current
routine ends if the determination result in S1 is negative. If the
determination result is affirmative, it is determined in S2,
corresponding to the working fluid temperature determination unit
60, whether or not the working fluid temperature TOIL is equal to
or lower than the preset working fluid criterion temperature Te on
the basis of the signal from the temperature sensor 54. The current
routine ends if the determination result in S2 is negative. If the
determination result is affirmative, in S3 corresponding to the
electric motor control unit 58, the electric motor 52 is actuated
on the basis of the electric motor control signal SM from the
electric motor control unit 58 and the electric motor-driven oil
pump 48 is driven. Under such control, the actuation of the
electric motor-driven oil pump is restricted and the electric power
used by the vehicle hydraulic device 100 is reduced.
[0044] FIG. 6 is one example of a relation (map) stored in advance
that is used by the electric motor control unit 58 to obtain the
working fluid temperature TOIL (.degree. C.) and the rotation speed
(rpm) of the electric motor-driven oil pump 48 required at a given
working fluid temperature. Specifically, as the temperature of the
working fluid rises, the oil pressure of the working fluid
discharged from the electric motor-driven oil pump 48 is reduced,
i.e., the rotation speed of the electric motor-driven oil pump 48
is reduced, and thus the electric power used by the vehicle
hydraulic device 100 is reduced.
[0045] While the present disclosure has been described in detail
with reference to the drawings, the present disclosure can also be
implemented in other embodiments, and various modifications can be
made within the scope of the disclosure.
[0046] For example, in the vane pump 14 of the first embodiment and
the second embodiment, the cam ring 70 having the inner peripheral
cam surface 78 is fitted in the recess 16 of the body 68. However,
the present disclosure is not limited thereto, and, for example,
the cam ring may be omitted by forming the inner peripheral cam
surface 78, facing the outer peripheral surface of the rotor 74,
directly on the inner peripheral surface of the recess 16 of the
body 68.
[0047] In the vane pump of the first embodiment and the second
embodiment, the plurality of discharge ports 26, 28 communicate
with the oil pressure control device 12 and the working fluid is
supplied thereto. However, the working fluid may be supplied from
the plurality of discharge ports 26, 28 to separate oil pressure
control devices. In that case, a plurality of shuttle valves 50 may
be used respectively for the plurality of discharge ports 26, 28,
or only one shuttle valve 50 may be used to control the oil
pressure of the working fluid in the backpressure oil passage 36 to
be supplied to the vanes 82.
* * * * *