U.S. patent application number 16/489710 was filed with the patent office on 2020-01-02 for oil pump.
The applicant listed for this patent is Nidec Tosok Corporation. Invention is credited to Takamitsu ETO, Koji HIGUCHI, Shigehiro KATAOKA, Yoshiyuki KOBAYASHI.
Application Number | 20200003209 16/489710 |
Document ID | / |
Family ID | 63585290 |
Filed Date | 2020-01-02 |
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United States Patent
Application |
20200003209 |
Kind Code |
A1 |
ETO; Takamitsu ; et
al. |
January 2, 2020 |
OIL PUMP
Abstract
An oil pump includes a motor including a shaft disposed along a
central axis extending in an axial direction, a rotor rotatable
around the shaft, a stator disposed to face the rotor, a housing
that accommodates the rotor and the stator, a pump including a pump
rotor rotatable together with the shaft to suction and discharge
oil, and a pump housing including an accommodation portion that
accommodates the pump rotor. The pump housing includes an intake
port through which the oil is suctioned, a discharge port through
which the oil is discharged, and a pressure sensor disposed between
the discharge port and the accommodation portion.
Inventors: |
ETO; Takamitsu; (Zama-shi,
JP) ; KOBAYASHI; Yoshiyuki; (Zama-shi, JP) ;
HIGUCHI; Koji; (Zama-shi, JP) ; KATAOKA;
Shigehiro; (Zama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nidec Tosok Corporation |
Zama-shi, Kanagawa |
|
JP |
|
|
Family ID: |
63585290 |
Appl. No.: |
16/489710 |
Filed: |
March 12, 2018 |
PCT Filed: |
March 12, 2018 |
PCT NO: |
PCT/JP2018/009454 |
371 Date: |
August 29, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F04C 2/102 20130101;
F04C 15/06 20130101; F04C 14/24 20130101; F04C 2240/81 20130101;
F04C 2240/30 20130101; F04C 2270/18 20130101; F04C 2210/206
20130101 |
International
Class: |
F04C 14/24 20060101
F04C014/24; F04C 15/06 20060101 F04C015/06 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 23, 2017 |
JP |
2017-057045 |
Claims
1-10. (canceled)
11. An oil pump comprising: a motor including a shaft disposed
along a central axis extending in an axial direction, a rotor
rotatable around the shaft, a stator disposed to face the rotor,
and a housing that accommodates the rotor and the stator; and a
pump including a pump rotor rotatable with the shaft to suction and
discharge oil, and a pump housing including an accommodation
portion that accommodates the pump rotor; wherein the pump housing
includes an intake port through which the oil is suctioned, a
discharge port through which the oil is discharged, and a pressure
sensor which is disposed between the discharge port and the
accommodation portion.
12. The oil pump according to claim 11, wherein the discharge port
includes a first discharge port and a second discharge port; and
the pressure sensor is disposed between any one of the first
discharge port and the second discharge port and the accommodation
portion.
13. The oil pump according to claim 12, wherein in a state that the
discharge port is fully opened, the second discharge port has a
flow rate of the oil larger than a flow rate of the oil in the
first discharge port; and the pressure sensor is disposed between
the accommodation portion and the second discharge port.
14. The oil pump according to claim 12, wherein the pump includes a
solenoid valve to adjust the flow rate of the oil discharged from
the accommodation portion; and the solenoid valve includes an
opening and closing portion capable of opening and closing a flow
path disposed between the discharge port and the accommodation
portion.
15. The oil pump according to claim 14, wherein the solenoid valve
includes a second suction port through which pressurized oil
discharged from the pump is suctioned, and a third discharge port
through which the pressurized oil is discharged toward an oil pan
that stores the pressurized oil; the pump housing includes a pump
body including the accommodation portion that accommodates the pump
rotor and includes a side surface and a bottom surface located on
the other side of the motor in the axial direction, a pump cover
that closes an opening portion that opens from one side of the pump
body in the axial direction to one side of the accommodation
portion in the axial direction, and a receiving port that receives
the oil discharged from the accommodation portion; the pump cover
includes a first flow path that communicates the receiving port
with the first discharge port, and a second flow path that
communicates the receiving port with the second discharge port; the
second flow path communicates the receiving port with the second
discharge port through the second suction port of the solenoid
valve; and the second discharge port of the pump cover is connected
to the third discharge port of the solenoid valve.
16. The oil pump according to claim 15, wherein the pump cover is
disposed on one side of the motor in the axial direction; and an
axial region of the pump cover is different from an axial region of
the motor.
17. The oil pump according to claim 15, wherein the pump cover
includes a protruding portion that protrudes radially outward from
an outer periphery of the motor, and the protruding portion
includes the second flow path and the second discharge port.
18. The oil pump according to claim 17, wherein the pressure sensor
and the solenoid valve are fixed to the protruding portion and
extend toward the motor.
19. The oil pump according to claim 17, wherein the pressure sensor
is disposed so that a longitudinal direction thereof is parallel or
substantially parallel to the axial direction.
20. The oil pump according to claim 15, wherein the second flow
path extends in a direction orthogonal or substantially orthogonal
to the axial direction of the motor and penetrates from an inside
of the pump cover to an outer peripheral portion thereof; and a
seal is disposed at an opening end of the second flow path that
opens to the outer peripheral portion of the pump cover.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a U.S. national stage of PCT Application No.
PCT/JP2018/009454, filed on Mar. 12, 2018, and priority under 35
U.S.C. .sctn. 119(a) and 35 U.S.C. .sctn. 365(b) is claimed from
Japanese Application No. 2017-057045, filed Mar. 23, 2017; the
entire disclosures of each application are hereby incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an oil pump.
BACKGROUND
[0003] In recent years, since an electric oil pump used for a
transmission or the like has been installed in an existing space of
a vehicle, restrictions on mounting have been severe, and
downsizing is required so that the electric oil pump can be
installed in various mounting spaces.
[0004] Further, oil vibration of oil discharged from the electric
oil pump may cause an operation of a transmission in a half clutch
state to become unstable. To eliminate such concern, increasing RPM
of the oil pump can be considered. However, when the RPM is simply
increased, a flow rate of oil increases, a pressure becomes
excessive, and thus a pressure in the half clutch state cannot be
maintained.
[0005] On the other hand, Japanese Unexamined Patent Application
Publication No. 2015-148310 discloses a control device of a
continuously variable transmission capable of restraining
amplification of oil vibration generated in a control valve unit
due to oil vibration of oil discharged from an electric oil pump. A
torque converter, a forward and reverse switching mechanism, and a
plurality of valves that control an operation of each of belt-type
continuously variable transmission mechanisms, which constitute the
continuously variable transmission, are provided in the control
valve unit. The plurality of valves control the operation of the
plurality of devices of the continuously variable transmission by
controlling supply and discharge of the oil discharged from the
electric oil pump. In a control device of the continuously variable
transmission, when there is a possibility that the oil vibration
may be amplified in the control valve unit, the amplification of
the oil vibration is restrained by increasing a line pressure which
connects the electric oil pump with the control valve unit.
[0006] The control device of the continuously variable transmission
described in Japanese Unexamined Patent Application Publication No.
2015-148310 can restrain the amplification of the oil vibration of
the oil discharged from the electric oil pump by increasing the
line pressure. However, in the control device of the continuously
variable transmission described in Japanese Unexamined Patent
Application Publication No. 2015-148310, there is no means for
directly detecting the line pressure, and the line pressure is
detected from a command signal to a line pressure solenoid valve
which controls the line pressure. Thus, the detected line pressure
may not be accurate.
SUMMARY
[0007] Example embodiments of the present disclosure provide oil
pumps each capable of accurately detecting a line pressure and also
being miniaturized.
[0008] An example embodiment of the present disclosure is an oil
pump including a motor including a shaft disposed along a central
axis extending in an axial direction, a rotor rotatable around the
shaft, a stator disposed to face the rotor, a housing that
accommodates the rotor and the stator, a pump including a pump
rotor rotatable with the shaft to suction and discharge oil, and a
pump housing including an accommodation portion that accommodates
the pump rotor. The pump housing includes an intake port through
which the oil is suctioned, a discharge port through which the oil
is discharged, and a pressure sensor which is disposed between the
discharge port and the accommodation portion.
[0009] According to an example embodiment of the present
disclosure, it is possible to provide an oil pump that is able to
accurately detect line pressure and is able to be miniaturized.
[0010] The above and other elements, features, steps,
characteristics and advantages of the present disclosure will
become more apparent from the following detailed description of the
example embodiments with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates a perspective view of an oil pump
according to a first example embodiment of the present
disclosure.
[0012] FIG. 2 illustrates a cross-sectional view of a main portion
of the oil pump.
[0013] FIG. 3 illustrates a perspective view of the oil pump which
shows an internal structure of a pump cover.
[0014] FIG. 4 illustrates a plan view of the oil pump which shows
the internal structure of the pump cover.
[0015] FIG. 5 illustrates an exploded perspective view of the pump
cover in which a solenoid valve and a pressure sensor are
installed.
[0016] FIG. 6 illustrates an exploded perspective view of the oil
pump in which the pump cover is installed at a motor section
provided with a pump body.
DETAILED DESCRIPTION
[0017] Hereinafter, oil pumps according to example embodiments of
the present disclosure will be described with reference to the
drawings. However, the dimensions, materials, shapes, relative
arrangements and the like of the component parts described in the
example embodiments or shown in the drawings are not intended to
limit the scope of the present disclosure to the described contents
but are merely illustrative examples. For example, an expression
representing a relative or unambiguous arrangement, such as "in a
direction," "along a direction," "parallel," "orthogonal,"
"center," "concentric" or "coaxial," not only represents such an
arrangement strictly, but also represents a relatively displaced
state with a tolerance or an angle and a distance which can obtain
the same function. For example, an expression representing that
things are in the same state, such as "identical," "equal" and
"homogeneous," not only represents equal states strictly, but also
represents a state in which a tolerance or a difference in which
the same function can be obtained is present. For example, an
expression representing shapes such as a square shape and a
cylindrical shape not only represents shapes such as a square shape
and a cylindrical shape in a geometrically strict sense, but also
represents shapes including an uneven portion, a chamfered portion,
and the like in the range in which the same effect can be obtained.
On the other hand, an expression "comprising," "having," "having,"
"including" or "having" one component is not an exclusive
expression excluding the presence of other components.
[0018] Further, in the drawings, an XYZ coordinate system is shown
as a three-dimensional orthogonal coordinate system as appropriate.
In the XYZ coordinate system, a Z-axis direction is a direction
parallel to one axial direction of a central axis J shown in FIG.
1. An X-axis direction is a direction parallel to a short side
direction of an oil pump shown in FIG. 1, that is, a vertical
direction in FIG. A Y-axis direction is orthogonal to both the
X-axis direction and the Z-axis direction.
[0019] Further, in the following description, a positive side (+Z
side) in the Z-axis direction is referred to as "front side," and a
negative side (-Z side) in the Z-axis direction is referred to as
"rear side." "Rear side" and "front side" are names used merely for
the purpose of explanation and do not limit the actual positional
relationship or direction. Also, unless otherwise indicated, a
direction parallel to the central axis J (the Z-axis direction) is
simply referred to as "axial direction," a radial direction about
the central axis J is simply referred to as "radial direction," and
a circumferential direction about the central axis J, that is, a
circumference of the central axis J (in a .theta. direction), is
simply referred to as "circumferential direction."
[0020] In the specification, the term "extending in the axial
direction" includes not only extending strictly in the axial
direction (the Z-axis direction) but also extending in a direction
inclined at a range of less than 45.degree. with respect to the
axial direction. Further, in the specification, the term "extending
in the radial direction" includes not only extending strictly in
the radial direction, that is, in a direction perpendicular to the
axial direction (the Z-axis direction), but also extending in a
direction inclined at a range of less than 45.degree. with respect
to the radial direction.
[0021] FIG. 1 illustrates a perspective view of an oil pump
according to a first example embodiment. FIG. 2 illustrates a
cross-sectional view of a main part of the oil pump.
First Example Embodiment
[0022] An oil pump 1 of the example embodiment has a motor section
20 and a pump section 3 as shown in FIGS. 1 and 2. The motor
section 20 has a shaft 41 disposed along a central axis J which
extends in the axial direction. The pump section 3 is located on
one side of the motor section 20 in the axial direction and is
driven by the motor section 20 via the shaft 41 to discharge oil.
That is, the motor section 20 and the pump section 3 are provided
side by side in the axial direction. Hereinafter, the respective
components will be described in detail.
<Motor Section 20>
[0023] As shown in FIG. 2, the motor section 20 includes a housing
21, a rotor 40, a shaft 41, a stator 50, and a bearing 55.
[0024] The motor section 20 is, for example, an inner rotor type
motor, the rotor 40 is fixed to an outer circumferential surface of
the shaft 41, and the stator 50 is located radially outward from
the rotor 40. In addition, the bearing 55 is disposed at an end
portion of the shaft 41 on the rear side (the -Z side) in the axial
direction and rotatably supports the shaft 41.
(Housing 21)
[0025] The housing 21 has a thin cylindrical shape with a bottom,
and includes a bottom surface portion 21a, a stator holding part
21b, a pump body holding part 21c, a side wall portion 21d, and
flange portions 24 and 25. The bottom surface portion 21a forms a
bottomed portion, and the stator holding part 21b, the pump body
holding part 21c, and the side wall portion 21d form a cylindrical
side wall surface centered on the central axis J. In the example
embodiment, an inner diameter of the stator holding part 21b is
larger than an inner diameter of the pump body holding part 21c. An
outer surface of the stator 50, that is, an outer surface of a core
back portion 51 which will be described below, is fitted to an
inner surface of the stator holding part 21b. Therefore, the stator
50 is accommodated in the housing 21.
[0026] The flange portion 24 extends radially outward from an end
portion of the side wall portion 21d on the front side (the +Z
side). On the other hand, the flange portion 25 extends radially
outward from an end portion of the stator holding part 21b on the
rear side (the -Z side). The flange portion 24 and the flange
portion 25 face each other and are fastened by a fastening means
(not shown). Therefore, the motor section 20 and the pump section 3
are sealed and fixed in the housing 21.
[0027] For example, a zinc-aluminum-magnesium-based alloy or the
like can be used as a material of the housing 21, and specifically,
a hot-dip zinc-aluminum-magnesium alloy plated steel plate and a
steel strip can be used. Since the housing 21 is formed of a metal
and has high heat conductivity and a large surface area, a heat
radiation effect is high. Further, a bearing holding part 56 for
holding the bearing 55 is provided on the bottom surface portion
21a.
(Rotor 40)
[0028] The rotor 40 has a rotor core 43 and a rotor magnet 44. The
rotor core 43 is fixed to the shaft 41 to surround the shaft 41
around an axis thereof (in the .theta. direction). The rotor magnet
44 is fixed to an outer surface of the rotor core 43 around an axis
thereof (in the .theta. direction). The rotor core 43 and the rotor
magnet 44 rotate with the shaft 41.
(Stator 50)
[0029] The stator 50 surrounds the rotor 40 around an axis thereof
(in the .theta. direction) and rotates the rotor 40 around the
central axis J. The stator 50 has the core back portion 51, a tooth
portion 52, a coil 53, and an insulator (a bobbin) 54.
[0030] The core back portion 51 has a cylindrical shape which is
concentric with the shaft 41. The tooth portion 52 extends from an
inner surface of the core back portion 51 toward the shaft 41. A
plurality of tooth portions 52 are provided and are disposed at
equal intervals in the circumferential direction of the inner
surface of the core back portion 51. The coil 53 is provided around
the insulator (the bobbin) 54, and a conductive wire 53a is wound
thereon. The insulator (the bobbin) 54 is installed at each of the
tooth portions 52.
(Bearing 55)
[0031] The bearing 55 is disposed on the rear side (the -Z side) of
the rotor 40 and the stator 50 and is held by the bearing holding
part 56. The bearing 55 supports the shaft 41. A shape, structure,
and the like of the bearing 55 are not particularly limited, and
any known bearing can be used.
(Shaft 41)
[0032] The shaft 41 extends along the central axis J and passes
through the motor section 20. The front side (the +Z side) of the
shaft 41 protrudes from the motor section 20 and extends into the
pump section 3. An end portion of the shaft 41 on the front side
(the +Z side) is disposed in a discharge port 11 of a pump cover 8.
The rear side (the -Z side) of the shaft 41 is protrudes from the
motor section 20 and is supported by the bearing 55 installed in a
bus bar holder 58.
<Pump Section 3>
[0033] The pump section 3 is located on one side of the motor
section 20 in the axial direction, specifically, on the front side
(the +Z side). The pump section 3 is driven by the motor section 20
via the shaft 41. The pump section 3 has a pump rotor 4 and a pump
housing 5. The pump housing 5 has an intake port 9, the discharge
port 11, and a pressure sensor 70. Furthermore, the pump housing 5
has a pump body 6, the pump cover 8 and a receiving port 12.
(Pump Body 6)
[0034] The pump body 6 is fixed into the front side (the +Z side)
of the housing 21 on the front side of the motor section 20. The
pump body 6 has an accommodation portion 7 which accommodates the
pump rotor 4 and has a side surface and a bottom surface located on
the other side of the motor section 20 in the axial direction. The
accommodation portion 7 opens on the front side (the +Z side) and
is recessed on the rear side (the -Z side). A shape seen in the
axial direction of the accommodation portion 7 is circular.
[0035] The pump body 6 has a through hole 6a which passes
therethrough along the central axis J. Both ends of the through
hole 6a in the axial direction open to allow the shaft 41 to pass
therethrough, an opening thereof on the front side (the +Z side)
opens to the accommodation portion 7, and an opening thereof on the
rear side (the -Z side) opens to the motor section 20 side. The
through hole 6a serves as a bearing which rotatably supports the
shaft 41.
(Pump Rotor 4)
[0036] The pump rotor 4 is installed on the shaft 41. More
specifically, the pump rotor 4 is installed on the front side (the
+Z side) of the shaft 41. The pump rotor 4 has an inner rotor 4a
installed on the shaft 41 and an outer rotor 4b which surrounds the
outside of the inner rotor 4a in the radial direction. The inner
rotor 4a has an annular shape. The inner rotor 4a is a gear having
teeth on an outer surface thereof in the radial direction.
[0037] The inner rotor 4a is fixed to the shaft 41. More
specifically, the end portion of the shaft 41 on the front side
(the +Z side) is press-fitted to the inside of the inner rotor 4a.
The inner rotor 4a rotates with the shaft 41 around an axis thereof
(in the .theta. direction). The outer rotor 4b has an annular shape
which surrounds the outside of the inner rotor 4a in the radial
direction. The outer rotor 4b is a gear which has teeth on an inner
surface thereof in the radial direction.
[0038] The inner rotor 4a and the outer rotor 4b engage with each
other, and the outer rotor 4b rotates as the inner rotor 4a
rotates. That is, rotation of the shaft 41 causes the pump rotor 4
to rotate. In other words, the motor section 20 and the pump
section 3 have the same rotation axis. Therefore, it is possible to
restrain an increase in size of the electric oil pump in the axial
direction. Further, the rotation of the inner rotor 4a and the
outer rotor 4b changes a volume of an engagement portion between
the inner rotor 4a and the outer rotor 4b. A region in which the
volume decreases is a pressure region, and a region in which the
volume increases is a negative pressure region. A suction port 10
is disposed on one side (the front side) of the negative pressure
region of the pump rotor 4 in the axial direction. Further, the
receiving port 12 is disposed in the pressure region of the pump
rotor 4 on one side (the front side) in the axial direction. Here,
the oil suctioned from the intake port 9 into the accommodation
portion 7 is accommodated in a volume portion between the inner
rotor 4a and the outer rotor 4b and is sent to the discharge port
11 side. Thereafter, the oil is discharged from the discharge port
11.
(Pump Cover 8)
[0039] The pump cover 8 is installed on one side (the front side)
of the pump body 6 in the axial direction and closes an opening
portion 7a opened to one side (the front side) of the accommodation
portion 7 in the axial direction. In the example embodiment shown
in FIGS. 1 and 2, the pump cover 8 has a disk-shaped cover main
body portion 8a which extends in the radial direction, and a
protruding portion 8b which protrudes from an end portion of the
cover main body portion 8a in the radial direction. The cover main
body portion 8a closes the opening portion 7a on the front side of
the accommodation portion 7.
(Cover Main Body Portion 8a)
[0040] The cover main body portion 8a has a first stepped portion
8a1 and a second stepped portion 8a2 which protrude on the front
side (the +Z side) in the axial direction. The first stepped
portion 8a1 has a cylindrical shape, is provided substantially
coaxially with the central axis J and is connected to a central
axis side end portion of a surface 8a3 of the cover main body
portion 8a on the front side (the +Z side) in the axial direction.
The cover main body portion 8a has a through hole 8a4 along the
central axis J. The through hole 8a4 passes through a space between
both end portions of the pump cover 8 in the axial direction. The
shaft 41 passes through the through hole 8a4.
[0041] The second step portion 8a2 is provided substantially
coaxially with the central axis J and has a cylindrical shape of
which a diameter is smaller than that of the first stepped portion
8a1. The second stepped portion 8a2 is connected to a central axis
side end portion of a surface 8a5 of the first stepped portion 8a1
on the front side (the +Z side) in the axial direction. The second
stepped portion 8a2 has a large diameter hole 8a6 having a diameter
larger than that of the through hole 8a4 along the central axis J,
and one end of the shaft 41 in the axial direction is disposed in
the large diameter hole 8a6.
[0042] The discharge port 11 has a first discharge port 11a and a
second discharge port 11b. In the example embodiment, the first
discharge port 11a is the large diameter hole 8a6. The second
discharge port 11b is provided on the tip end side of the
protruding portion 8b of the pump cover 8 which will be described
below in detail. The suction port 10 and a receiving port 12 are
provided in the other end of the cover main body portion 8a. The
suction port 10 is provided on the side opposite to the protruding
portion 8b with respect to the central axis J. The receiving port
12 is provided on the protruding portion 8b side with respect to
the central axis J.
[0043] More specifically, as shown in FIGS. 2 and 3, the suction
port 10 is provided at a position opposite to the negative pressure
region, curved in the circumferential direction with respect to the
central axis J and extends in the form of a long hole. Further, the
receiving port 12 is provided at a position opposed to the pressure
region, curved in the circumferential direction with respect to the
central axis J and extending in the form of a long hole. Therefore,
the oil suctioned from the intake port 9 can be supplied over
substantially the entire negative pressure region. Also, all of the
oil supplied from the pressure region can be received by the
receiving port 12.
[0044] The intake port 9 communicates with the suction port 10 and
opens to one end of the first stepped portion 8a1 in the axial
direction. That is, the intake port 9 is provided across the cover
main body portion 8a and the first stepped portion 8a1. Thus, the
intake port 9 is connected to the negative pressure region of the
accommodation portion 7 via the suction port 10.
[0045] The first discharge port 11a and the receiving port 12 are
connected via a communication path 15. In the example embodiment
shown in FIG. 2, one end of the communication path 15 opens to an
inner side surface of the first discharge port 11a, and the other
end thereof opens to one side (the front side) of the receiving
port 12 in the axial direction. Therefore, the oil received in the
receiving port 12 can flow to the first discharge port 11a through
the communication path 15. A flow path 17 through which the oil
flows between the receiving port 12 and the first discharge port
11a is hereinafter referred to as a first flow path 13.
[0046] A control valve 81 is connected to the first discharge port
11a via a main flow path 80. The main flow path 80 supplies the oil
discharged from the first discharge port 11a to the control valve
81. The control valve 81 controls supply and discharge of the oil
supplied from the main flow path 80 to, for example, an automatic
transmission of a vehicle.
(Protruding Portion 8b)
[0047] As shown in FIGS. 1 and 2, the protruding portion 8b
protrudes from the other radial end portion of the cover main body
portion 8a in a direction perpendicular to the axial direction. A
tip end of the protruding portion 8b is located radially outward
from the housing 21 of the motor section 20. The protruding portion
8b has a substantially rectangular shape when seen from one side
(the front side) in the axial direction. A solenoid insertion hole
8b1 (refer to FIG. 5) is provided on the tip end side of the
protruding portion 8b to pass therethrough in the axial direction.
The second discharge port 11b is an opening portion which opens to
one side (the front side) of the solenoid insertion hole 8b1 in the
axial direction. Hereinafter, the flow path 17 which communicates
the second discharge port 11b with the accommodation portion 7 will
be referred to as a second flow path 14.
(Second Flow Path 14)
[0048] As shown in FIGS. 2, 3 and 4, one end of the second flow
path 14 is connected to the receiving port 12, and the other end
thereof is connected to the second discharge port 11b via a
solenoid valve 60. In the illustrated example embodiment, the
second flow path 14 passes through a first through hole 14a which
extends from the receiving port 12 to the tip end side of the
protruding portion 8b and passes through at the tip end portion of
the protruding portion 8b, and a second through hole 14b which
extends from an end portion of the protruding portion 8b on one
side (the negative side in the Y-axis direction) in the right and
left direction toward the solenoid insertion hole 8b1, passes
through the solenoid insertion hole 8b1, extends to the pressure
sensor insertion hole 8b2 side while intersecting the first through
hole 14a and opens to the pressure sensor insertion hole 8b2.
Sealing members 16 are provided at the opening portion of the first
through hole 14a on the tip end side of the protruding portion 8b
and at the opening portion of the second through hole 14b on one
side in the right and left direction of the protruding portion 8b
to close the opening portions. In the illustrated example
embodiment, the sealing members 16 are male screws.
[0049] That is, the second flow path 14 passes through a first
through hole portion 14a1 of the first through hole 14a between the
receiving port 12 and an intersection portion 14c at which the
first through hole 14a and the second through hole 14b intersect,
and a second through hole portion 14b1 of the second through hole
14b between the intersection portion 14c and the solenoid insertion
hole 8b1. Although the details will be described below, the second
through hole portion 14b1 is connected to a second suction port 62
of the solenoid valve 60. Further, a third discharge port 63 of the
solenoid valve 60 is connected to the second discharge port 11b.
Therefore, the second flow path 14 communicates the receiving port
12 with the second discharge port 11b via the second suction port
62 of the solenoid valve 60.
[0050] The second flow path 14 is provided in the pump cover 8 by,
for example, a cutting operation (for example, drilling). For
example, the first through hole 14a is cut from the tip end of the
protruding portion 8b of the pump cover 8 to the receiving port 12
side of the pump cover 8, and the second through hole 14b is then
cut from an end portion of an outer circumferential portion of the
protruding portion 8b on the positive side in the Y-axis direction
toward the solenoid insertion hole 8b1, the first through hole 14a
and the pressure sensor insertion hole 8b2. Additionally, female
threads are provided at an opening end of the first through hole
14a which opens to the outer circumferential portion of the
protruding portion 8b and an opening end of the second through hole
14b which opens to an end portion of the protruding portion 8b on
the positive side in the Y-axis direction, and the sealing member
16 is screwed and fixed into each of the opening ends. Thus, the
second flow path 14 may be provided in the pump cover 8 by cutting.
Therefore, workability of an operation for providing the second
flow path 14 inside the pump cover 8 can be improved.
[0051] Thus, as shown in FIG. 2, the pump cover 8 includes the
cover main body portion 8a and the protruding portion 8b. The pump
cover 8 is disposed on one side (the front side) of the motor
section 20 in the axial direction, and an axial region of the pump
cover 8 is disposed in a region different from an axial region of
the motor section 20. In the illustrated example embodiment, the
axial region of the pump cover 8 is disposed in a region of the
motor section 20 on one side (the front side) in the axial
direction. That is, the axial region of the pump cover 8 does not
overlap the axial region of the motor section 20 in the axial
direction, and the axial region of the pump cover 8 is disposed at
a position at which it does not face the axial region of the motor
section 20.
[0052] Accordingly, as compared with a case in which the second
flow path 14 is provided on the outside of the motor section 20 in
the radial direction, a flow path length of the second flow path 14
can be shortened. Therefore, since the pressure sensor 70 can be
disposed in the vicinity of the pump rotor 4 serving as a hydraulic
pressure source, a pressure of the oil discharged from the pump
rotor 4 can be detected more accurately.
(Solenoid Valve 60)
[0053] FIG. 5 illustrates an exploded perspective view of the pump
cover 8 on which the solenoid valve 60 and the pressure sensor 70
are installed. As shown in FIGS. 2 and 5, the solenoid valve 60
includes a valve housing 64 which accommodates an opening and
closing part 65 to be movable therein, a drive part 66 which moves
the opening and closing part 65 relative to the valve housing 64,
and a solenoid feed line 67 of which one end portion is connected
to the drive part 66 and at the other end of which a solenoid valve
side feed terminal 67a is provided. The opening and closing part 65
extends in a longitudinal direction of the valve housing 64 and is
movably supported to open and close the second suction port 62. In
the illustrated example embodiment, the opening and closing part 65
is a spool.
[0054] The valve housing 64 has the second suction port 62 into
which the oil flowing in the second flow path 14 flows, and the
third discharge port 63 that discharges the flowed oil. The second
suction port 62 is opened and closed by movement of the opening and
closing part 65. Thus, the flow of the oil flowing through the
second flow path 14 can be blocked and allowed by opening and
closing the second suction port 62. When the second suction port 62
is opened, the second suction port 62 and the third discharge port
63 are in a communication state. Therefore, when the second suction
port 62 is opened, the oil flowing through the second flow path 14
is discharged from the second discharge port 11b through the second
suction port 62 and the third discharge port 63. Thus, some of the
oil flowing through the first flow path 13 can be allowed to flow
to the second flow path 14 side by the solenoid valve 60 opening
and closing the second flow path 14. Therefore, the flow rate of
the oil to a supply destination of the pressurized oil supplied
from the first discharge port 11a can be adjusted.
[0055] In the solenoid valve 60, when the second suction port 62 is
opened by the opening and closing part 65, the flow rate of the oil
discharged from the second discharge port 11b may be larger than
the flow rate of the oil discharged from the first discharge port.
In this case, for example, an opening area of the second discharge
port 11b is made larger than an opening area of the first discharge
port 11a. In this way, as an amount of oil flowing through the
second discharge port 11b is larger than that of the first
discharge port 11a, a range of flow rate adjustment of the oil
discharged from the first discharge port 11a can be expanded.
[0056] The drive part 66 is, for example, an electromagnetic
clutch. The drive part 66 moves the opening and closing part 65 by
a magnetic force generated from the drive part 66 and opens the
second suction port 62 when power is supplied to the drive part 66
and then returns the opening and closing part 65 to its original
position by biasing of a spring (not shown) and closes the second
suction port 62 when the power supply to the drive part 66 is cut
off. Therefore, a position of the opening and closing part 65 can
be adjusted to control the opening and closing of the second
suction port 62 by controlling the power supply to the drive part
66.
[0057] The third discharge port 63 opens to one end portion of the
valve housing 64 in the longitudinal direction (one end portion
thereof in the axial direction). On the other hand, the second
discharge port 11b provided in the protruding portion 8b is an
opening of the solenoid insertion hole 8b1 on one side (the front
side) in the axial direction. The valve housing 64 of the solenoid
valve 60 is inserted and fixed into the solenoid insertion hole
40b1. The valve housing 64 is supported in a state in which one end
portion thereof in the axial direction is located on substantially
the same plane as the second discharge port 11b. Thus, the second
discharge port 11b and the third discharge port 63 are disposed on
substantially the same plane, and the second discharge port 11b and
the third discharge port 63 are connected to each other to be in a
communication state.
[0058] The second discharge port 11b is connected to an oil pan T
capable of storing the oil. In the illustrated example embodiment,
the second discharge port 11b communicates with the oil pan T via a
tank flow path 83.
(Pressure Sensor 70)
[0059] As shown in FIG. 1, the pressure sensor 70 is fixed to the
protruding portion 8b and extends to the motor section 20 side. In
the illustrated example embodiment, the pressure sensor 70 is
disposed at the outside of the housing 21 of the motor section 20
and is fixed to an end portion of the protruding portion 8b on the
minus side in the Y axis direction. As shown in FIG. 5, the
pressure sensor 70 has a sensor part 72 which detects a hydraulic
pressure of the oil, and an electric line holding part 74 which
holds a sensor electrical line 75 electrically connected to the
sensor part 72. The sensor part 72 has a cylindrical shape, and a
male screw part 72a is provided on an outer circumferential surface
of the sensor part 72. A female screw portion to which the male
screw part 72a can be screwed is provided in the pressure sensor
insertion hole 8b2. Therefore, the pressure sensor 70 is fixed to
the pump cover 8 through the pressure sensor insertion hole
8b2.
[0060] As shown in FIG. 4, an opening portion 14b2 of the second
through hole 14b at an end portion thereof on the plus side in the
Y axis direction opens to a portion of the pressure sensor
insertion hole 8b2 into which the sensor part 72 is inserted. The
opening portion 14b2 communicates with the sensor part 72.
Therefore, the hydraulic pressure of the oil in each of the first
flow path 13 and the second flow path 14 can be detected through
the first through hole 14a and the second through hole 14b. That
is, when the second flow path 14 is closed by the solenoid valve
60, the pressure sensor 70 can detect the hydraulic pressure of the
oil in the first flow path 13, and when the second flow path 14 is
opened by the solenoid valve 60, the pressure sensor 70 can detect
the hydraulic pressure of the oil in the second flow path 14.
[0061] The pressure sensor 70 converts, for example, a change in
electrical resistance due to a piezoresistive effect into an
electrical signal. The electrical signal is transmitted to a sensor
side terminal 75a provided in the sensor electrical line 75 via the
sensor electrical line 75, as shown in FIG. 5. The electrical
signal transmitted to the sensor side terminal 75a is transmitted
to, for example, an engine controller. The engine controller
controls an operation of an automatic transmission, an engine, and
the like of a vehicle and controls an operation of the drive part
66 (refer to FIG. 2) of the solenoid valve 60 on the basis of the
electrical signal from the pressure sensor 70 to control the
opening and closing of the second suction port 62.
[0062] As described above, the sensor part 72 of the pressure
sensor 70 is fixed into the pressure sensor insertion hole 8b2 of
the protruding portion 8b. Further, the protruding portion 8b
extends in a direction orthogonal to the axial direction. Thus, as
shown in FIG. 2, the sensor part 72 of the pressure sensor 70 is
disposed between the first discharge port 11a or the second
discharge port 11b and the accommodation portion 7 when seen in the
direction orthogonal to the axial direction. In the example
embodiment, the sensor part 72 is disposed between the first
discharge port 11a and the accommodation portion 7 and between the
second discharge port 11b and the accommodation portion 7.
Accordingly, an end portion of the pressure sensor 70 on one side
(the front side) in the axial direction does not protrude from one
end portion of the oil pump 1 the axial direction. Therefore, an
increase in a length of the oil pump 1 in the axial direction can
be restrained. The sensor part 72 may be disposed between any one
of the first discharge port 11a and the second discharge port 11b
and the accommodation portion 7.
[0063] FIG. 6 illustrates an exploded perspective view of the oil
pump 1 in which the pump cover 8 is installed in the motor section
20 provided with the pump body 6.
[0064] As shown in FIGS. 1 and 6, the electric line holding part 74
of the pressure sensor 70 and the solenoid valve 60 are disposed
adjacent to each other and extend in the axial direction of the
motor section 20. In the illustrated example embodiment, the
solenoid valve 60 is disposed at the central portion of the
protruding portion 8b in the right and left direction (the Y-axis
direction) with respect to a protruding direction thereof, and the
electric line holding part 74 is disposed on one side of the
protruding portion 8b in the right and left direction. Further, the
electric line holding part 74 and the solenoid valve 60 are
disposed in a direction orthogonal to a surface of the protruding
portion 8b on the rear side (the -Z side) in the axial direction.
Therefore, since the pressure sensor 70 and the solenoid valve 60
are disposed in the axial direction of the motor section 20, the
oil pump 1 can be miniaturized as compared with a case in which the
pressure sensor 70 and the solenoid valve 60 are disposed in
directions different from each other.
<Operation and Effect of Oil Pump 1>
[0065] Next, an operation and an effect of the oil pump 1 will be
described. As shown in FIG. 2, when the motor section 20 of the oil
pump 1 is driven, the oil suctioned from the intake port 9 of the
pump section 3 moves in the accommodation portion 7 of the pump
section 3 and is discharged from the first discharge port 11a via
the receiving port 12 and the communication path 15. The oil
discharged from the first discharge port 11a is supplied to the
control valve 81 via the main flow path 80.
[0066] Here, since the pump section 3 according to the example
embodiment is a volume change type trochoid pump, oil vibration
occurs in the oil discharged from the oil pump 1 due to a pressure
fluctuation of the oil pump 1. Due to the oil vibration, for
example, when a clutch of an automatic transmission is brought into
a half clutch state, the operation may be unstable. In order to
eliminate this instability, it is conceivable to increase a
frequency of the oil vibration by increasing RPM of the oil pump 1
from, for example, 400 to 1200. However, simply increasing the RPM
to increase the frequency of the oil vibration may cause resonance
and thus may not prevent judder in the half clutch state.
[0067] Therefore, in the oil pump 1 according to the example
embodiment, the pump cover 8 of the pump housing 5 has a solenoid
valve 60 connected to the second flow path 14 which communicates
the discharge port 11 (the second discharge port 11b) with the
accommodation portion 7, such that some of the oil supplied from
the first discharge port 11a to the supply destination (for
example, the clutch destination) of the pressurized oil can flow to
the solenoid valve 60 side. Therefore, for example, in the case in
which the supply destination of the pressurized oil is the clutch
destination, even when the RPM of the oil pump 1 is increased from,
for example, 400 to 1200, it is possible to restrain an increase in
the flow rate of the oil supplied to the clutch. Therefore, the
frequency of the oil vibration can be increased and shifted to a
frequency for avoiding resonance. Accordingly, the pressure in the
half clutch state can be maintained while the judder in the half
clutch state is prevented.
[0068] Further, in the oil pump 1 according to the example
embodiment, the pressure sensor 70 capable of detecting the
hydraulic pressure of the oil in the second flow path 14 is
disposed between the discharge port 11 (the first discharge port
11a and the second discharge port 11b) and the accommodation
portion 7. Thus, an end portion of the pressure sensor 70 on one
side (the front side) in the axial direction does not protrude from
one end portion of the oil pump 1 the axial direction. Therefore,
the increase in the length of the oil pump 1 in the axial direction
can be restrained. Further, the oil pump 1 according to the example
embodiment can be disposed in the vicinity of the pump rotor 4
which is a generation source of the hydraulic pressure, as compared
with a case in which the pressure sensor 70 is provided in the
control valve 81. Accordingly, since the hydraulic pressure of the
oil discharged from the pump rotor 4 can be accurately detected,
the respective hydraulic pressures in the first flow path 13 and
the second flow path 14 can be accurately detected.
[0069] Also, the solenoid valve 60 has the second suction port
through which the pressurized oil discharged from the pump section
3 is suctioned, and the third discharge port 63 through which the
pressurized oil is discharged toward the oil pan T capable of
storing the oil. Furthermore, the pump housing 5 includes the pump
body 6 having the accommodation portion 7 which accommodates the
pump rotor 4 and has the side surface and the bottom surface
located on the other side of the motor section in the axial
direction, the pump cover 8 which closes the opening portion 7a
that opens from one side (the front side) of the pump body 6 in the
axial direction to one side (the front side) of the accommodation
portion 7 in the axial direction, and the receiving port 12 which
receives the oil discharged from the accommodation portion 7. The
pump cover 8 has the first flow path 13 which communicates the
receiving port 12 with the first discharge port 11a, and the second
flow path 14 which communicates the receiving port 12 with the
second discharge port 11b. The second flow path 14 communicates the
receiving port 12 with the second discharge port 11b via the second
suction port 62 of the solenoid valve 60. The second discharge port
11b of the pump cover 8 is connected to the third discharge port 63
of the solenoid valve 60.
[0070] Therefore, the second flow path 14 which connects the pump
section 3 with the solenoid valve 60 can be shortened. Therefore,
an increase in a size of the oil pump 1 can be restrained.
Moreover, as compared with a case in which the second flow path 14
is provided as a separate member, a number of parts can be reduced,
and an increase in cost of the oil pump 1 can be restrained.
[0071] Also, the pump cover 8 has the protruding portion 8b which
protrudes radially outward from an outer periphery of the motor
section 20, and the protruding portion 8b has the second flow path
14 and the second discharge port 11b. Therefore, the second flow
path 14 and the second discharge port 11b can be provided adjacent
to each other. Thus, the increase in the size of the oil pump 1 can
be restrained. Moreover, as compared with the case in which the
second flow path 14 is provided as a separate member, a number of
parts can be reduced, and the increase in the cost of the oil pump
1 can be restrained.
[0072] Further, the pressure sensor 70 and the solenoid valve 60
are fixed to the protruding portion 8b and extend toward the motor
section 20 side. Therefore, the pressure sensor 70 and the solenoid
valve 60 can be disposed along the motor section 20, and the
increase in the size of the oil pump 1 can be restrained.
[0073] Further, the pressure sensor 70 is disposed such that the
longitudinal direction thereof is parallel to the axial direction.
Therefore, the miniaturization of the pump device can be promoted
as compared with a case in which the longitudinal direction of the
pressure sensor 70 is disposed in a direction intersecting the
axial direction.
[0074] Although the preferred example embodiment of the present
disclosure have been described above, the present disclosure is not
limited to the example embodiment, and various modifications and
changes are possible within the scope of the present
disclosure.
[0075] While example embodiments of the present disclosure have
been described above, it is to be understood that variations and
modifications will be apparent to those skilled in the art without
departing from the scope and spirit of the present disclosure. The
scope of the present disclosure, therefore, is to be determined
solely by the following claims.
* * * * *