U.S. patent application number 13/390420 was filed with the patent office on 2012-06-28 for electric pump unit.
This patent application is currently assigned to JTEKT CORPORATION. Invention is credited to Takatoshi Sakata.
Application Number | 20120164009 13/390420 |
Document ID | / |
Family ID | 43732517 |
Filed Date | 2012-06-28 |
United States Patent
Application |
20120164009 |
Kind Code |
A1 |
Sakata; Takatoshi |
June 28, 2012 |
ELECTRIC PUMP UNIT
Abstract
An electric pump unit that may be compactified and that may be
reduced in weight and cost is provided. An electric pump unit is
configured such that a pump chamber having an oil suction port and
an oil discharge port is formed on an inner side of a motor stator
that is fixedly provided on an inner periphery of a synthetic resin
unit housing and only part of an inner peripheral side of which is
exposed to an inside of the unit housing, a pump outer rotor is
arranged on an inner side of the motor stator in the pump chamber
so as to be able to rotate using an inner periphery of the motor
stator as a guide, a pump inner rotor that is supported for
rotation by the unit housing is arranged on an inner side of the
pump outer rotor, and a motor rotor is formed such that a permanent
magnet is held by a synthetic resin permanent magnet holding
portion that is provided by integral molding on an outer periphery
of the pump outer rotor.
Inventors: |
Sakata; Takatoshi;
(Yamatotakada-shi, JP) |
Assignee: |
JTEKT CORPORATION
Osaka-shi, Osaka
JP
|
Family ID: |
43732517 |
Appl. No.: |
13/390420 |
Filed: |
September 10, 2010 |
PCT Filed: |
September 10, 2010 |
PCT NO: |
PCT/JP2010/065611 |
371 Date: |
February 14, 2012 |
Current U.S.
Class: |
417/410.4 ;
418/171 |
Current CPC
Class: |
F04C 2/084 20130101;
F04C 2240/40 20130101; F04C 2/102 20130101; F04C 11/008 20130101;
F04C 15/008 20130101; F04C 2240/30 20130101 |
Class at
Publication: |
417/410.4 ;
418/171 |
International
Class: |
F04B 17/03 20060101
F04B017/03; F04C 2/10 20060101 F04C002/10 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 11, 2009 |
JP |
2009-209992 |
Claims
1. An electric pump unit comprising: a unit housing made of
synthetic resin; a motor stator that is fixed to an inner periphery
of the unit housing in a state where part of an inner peripheral
side of the motor stator is exposed; and a pump chamber that is
formed on an inner side of the motor stator and that has a fluid
suction port and a fluid discharge port, wherein a pump outer rotor
that is able to rotate using an inner periphery of the motor stator
as a guide and a pump inner rotor that is supported for rotation by
the unit housing are arranged in the pump chamber, a permanent
magnet holding portion made of synthetic resin is integrally molded
on an outer periphery of the pump outer rotor, and a motor rotor is
formed such that a permanent magnet is held by the permanent magnet
holding portion.
2. The electric pump unit according to claim 1, wherein a back yoke
made of an iron-based material is in-molded in the pump outer
rotor.
Description
TECHNICAL FIELD
[0001] The invention relates to an electric pump unit that is used
as a hydraulic pump that supplies hydraulic pressure to, for
example, a transmission (speed change gear), or the like, of an
automobile.
BACKGROUND ART
[0002] In recent years, an electric pump unit is used as a
hydraulic pump of an automobile in order to achieve energy saving
by minutely controlling start and stop of the electric pump unit
and to ensure hydraulic pressure supplied to a drive train, such as
a transmission, even during a stop of an engine through an idle
stop (idling stop).
[0003] An electric pump unit for an automobile is mounted in a
limited space of a vehicle body, so the electric pump unit is
required to be compactified, and also required to be light in
weight and reduced in cost. There is suggested an electric pump
unit in response to this request such that a pump, a pump driving
electric motor and a controller of the motor are integrally
assembled in a common unit housing (for example, see Patent
Document 1).
RELATED ART DOCUMENT
Patent Document
[0004] Patent Document 1: Japanese Patent Application Publication
No. 2008-215088
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0005] In the above described existing electric pump unit, the pump
and the motor are coupled via a motor shaft and are aligned in the
axial direction, so the size in the axial direction is large, and
there is a limit of compactification.
[0006] One object of the invention is to provide an electric pump
unit that may be compactified and that may be reduced in weight and
cost.
Means for Solving the Problems
[0007] An electric pump unit according to an aspect of the
invention is configured such that a pump chamber having a fluid
suction port and a fluid discharge port is formed on an inner side
of a motor stator that is fixedly provided on an inner periphery of
a synthetic resin unit housing and only part of an inner peripheral
side of which is exposed to an inside of the unit housing, a pump
outer rotor is arranged on an inner side of the motor stator in the
pump chamber so as to be able to rotate using an inner periphery of
the motor stator as a guide, a pump inner rotor that is supported
for rotation by the unit housing is arranged on an inner side of
the pump outer rotor, and a motor rotor is formed such that a
permanent magnet is held by a synthetic resin permanent magnet
holding portion that is provided by integral molding on an outer
periphery of the pump outer rotor.
[0008] With the electric pump unit, as described above, it is
possible to reduce the size in the axial direction, and further
compactification and reduction in weight and cost are possible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a longitudinal sectional view of an electric pump
unit that shows an embodiment of the invention.
[0010] FIG. 2 is a sectional view that is taken along the line
II-II in FIG. 1.
[0011] FIG. 3 is an exploded perspective view of a pump outer
rotor.
EMBODIMENTS OF THE INVENTION
[0012] Hereinafter, an embodiment in which the invention is applied
to a hydraulic pump of an automobile will be described with
reference to the drawings.
[0013] FIG. 1 is a longitudinal sectional view of an electric pump
unit. Note that, in the following description, the left side in
FIG. 1 is defined as front side, and the right side is defined as
rear side.
[0014] The electric pump unit is formed such that a pump and a pump
driving electric motor are integrally assembled in a unit housing 1
made of synthetic resin. In this example, the pump is an internal
gear pump, and the motor is a DC brushless motor having three-phase
coils. A controller (not shown) of the motor is provided separately
from the electric pump unit.
[0015] The housing 1 is formed of a rear-side housing body 2 and a
front-side lid 3. The housing body 2 has a cylindrical shape such
that the rear end of a cylindrical portion 2a is closed by a rear
wall 2b and a front portion is open. A short cylindrical portion 2c
that has an outside diameter smaller than the bore diameter of the
cylindrical portion 2a and that is concentric with the cylindrical
portion 2a is integrally formed at the center of the front surface
(inner surface) of the rear wall 2b. The lid 3 has a disc shape,
and a short cylindrical portion 3a that is concentric with the
short cylindrical portion 2c of the housing body 2 and that has an
outside diameter equal to the outside diameter of the short
cylindrical portion 2c is integrally formed at the center of the
rear surface (inner surface) of the lid 3. The outer peripheral
portion of the lid 3 is fixed to the front end surface of the
cylindrical portion 2a of the housing body 2 via an O ring 4.
Although not shown in the drawing, a connector is provided at an
appropriate portion of the outer surface of the housing body 2.
[0016] A motor stator 5 is fixedly provided on the inner periphery
of the cylindrical portion 2a of the housing body 2. The stator 5
is formed such that a portion that includes the inner peripheral
surface of a core 6 formed of laminated steel plate is covered with
an insulator (insulator made of synthetic resin) 7, and coils 8 are
wound around the portion of the insulator 7. The coils 8 are
connected to the connector (not shown). In this example, the stator
5 is integrally molded on the inner periphery of the cylindrical
portion 2a, the front portion of the insulator 7 and coils 8 is
covered with an inward flange portion 2d that is formed integrally
with the front end of the cylindrical portion 2a of the housing
body 2, and the rear portion of the insulator 7 and coils 8 is
covered with the rear wall 2b of the housing body 2. In addition,
the outer periphery of the portion of the insulator 7 on the front
and rear sides of the core 6 is in close contact with the inner
periphery of the cylindrical portion 2a, the inner periphery of the
insulator 7 is in close contact with the outer periphery of the
short cylindrical portion 3a of the lid 3 and the outer periphery
of the short cylindrical portion 2c of the housing body 2, and the
inner periphery of the insulator 7 on the inner side of the core 6
is exposed to the inside of the housing 2. Then, a pump chamber 9
is formed on the inner side of the stator 5 between both short
cylindrical portions 2c and 3a.
[0017] A pump outer rotor (outer gear) 10 is arranged on the inner
side of the stator 5 inside the pump chamber 9 so as to be able to
rotate using the inner periphery of the stator 5 as a guide, and a
pump inner rotor (inner gear) 11 that is supported for rotation by
the housing 2 and that is in mesh with the outer rotor 10 is
arranged on the inner side of the outer rotor 10.
[0018] The outer rotor 10 is made of synthetic resin. Teeth 10a are
formed on the inner periphery of the outer rotor 10, and a motor
rotor 14 having permanent magnets 13 is provided on the outer
periphery of the outer rotor 10.
[0019] The motor rotor 14 is formed such that the segmented
permanent magnets 13 are held at multiple portions (eight portions
in this example) that equally divide a synthetic resin permanent
magnet holding portion 15, which is fixedly provided on the outer
periphery of the outer rotor 10, in the circumferential direction.
The outer rotor 10 made of synthetic resin is integrally molded
with the permanent magnet holding portion 15 in a state where a
back yoke 16 made of an iron-based material is in-molded. The
permanent magnet holding portion 15 has an outward rib 15a that is
integrally formed with the outer peripheral rear end of the outer
rotor 10 and permanent magnet holding protrusions 15b that are
integrally formed at multiple portions that equally divide the
outer periphery of the outer rotor 10 in the circumferential
direction and that extend from the front surface of the rib 15a to
the front end of the outer rotor 10. The outer peripheries of the
protrusions 15b form a cylindrical surface as in the case of the
rib 15a, and the diameters of both cylindrical surfaces are equal
to each other. Each protrusion 15b has a V-shaped cross-sectional
shape, and the mutual space between the adjacent protrusions 15b
gradually reduces radially outward. The width of each permanent
magnet 13 in the circumferential direction also gradually reduces
radially outward, and each permanent magnet 12 is inserted from the
front side and held between the adjacent protrusions 15b. The outer
periphery of the rib 15a and the outer peripheries of the
protrusions 15b are in slide contact with the inner periphery of
the insulator 7 exposed to the inside of the housing 2, and the
outer rotor 10 uses them as a guide to rotate. The outer peripheral
surface of the back yoke 16 in-molded in the outer rotor 10 is
exposed from the outer rotor 10 between the adjacent protrusions
15b, that is, the portions at which the permanent magnets 13 are
held.
[0020] The inner rotor 11 is made of synthetic resin or made of a
sintered compact of an iron-based material. Both ends of a shaft 17
extending in the longitudinal direction are rotationally supported
by the short cylindrical portion 3a of the lid 3 and the short
cylindrical portion 2c of the housing body 2, and the inner rotor
11 is fixed to the shaft 17. Teeth 11a are formed on the outer
periphery of the inner rotor 11.
[0021] The lid 3 has an oil suction port 18 and an oil discharge
port 19 that are in fluid communication with the pump chamber
9.
[0022] The electric motor is formed of the stator 5 and the rotor
14 of the outer rotor 10, and the pump is formed of the outer rotor
10 and the inner rotor 11.
[0023] The controller of the motor is arranged separately from the
electric pump unit, and is connected to the motor via the connector
(not shown) of the housing body 2.
[0024] While the vehicle is running, the motor is stopped, so the
pump is stopped.
[0025] During a stop of the vehicle, the motor operates. By so
doing, the outer rotor 10 integrated with the motor rotor 14
rotates, and the pump operates. As the pump operates, oil is
introduced into the pump chamber 9 via the suction port 18, and is
discharged via the discharge port 19.
[0026] The electric pump unit according to this embodiment is
configured such that the pump is arranged inside the motor stator 5
that constitutes the electric motor, so the size in the axial
direction is small, and further compactification is possible. In
addition, the motor rotor 14 is integrated with the outer periphery
of the pump outer rotor 10, so the number of components is small,
and further reduction in weight and cost is possible. The outer
rotor 10 integrated with the motor rotor 14 is configured to rotate
using the inner periphery of the motor stator 5 as a guide, so it
is possible to properly keep the gap in the radial direction
between the motor stator 5 and the permanent magnets 12 of the
motor rotor 14.
[0027] The motor rotor 14 is formed such that the permanent magnets
13 are held by the synthetic resin permanent magnet holding member
15 that is formed by integral molding on the outer periphery of the
outer rotor 10, so it is not necessary to fix the permanent magnets
13 to the outer rotor 10 by adhesive agent and, therefore, there is
no possibility of peeling of the permanent magnets 13.
[0028] In the electric pump unit according to this embodiment, for
example, the outer periphery of the permanent magnet holding
portion is guided by the inner periphery of the motor stator.
[0029] Furthermore, in the electric pump unit according to this
embodiment, for example, the back yoke made of an iron-based
material is in-molded in the pump outer rotor that is integrally
molded with the permanent magnet holding portion.
[0030] By so doing, it is possible to easily mold the pump outer
rotor integrated with the motor rotor.
[0031] The overall configuration and configuration of portions of
the electric pump unit are not limited to the ones of the above
embodiment, and may be appropriately modified.
[0032] In addition, the invention may be applied to an electric
pump unit other than the electric pump unit for an automobile.
[0033] Furthermore, in the above embodiment, the electric pump unit
that introduces and discharges oil is described; however, the
electric pump unit is not limited to this configuration. The
electric pump unit may introduce and discharge another fluid, such
as water.
DESCRIPTION OF REFERENCE NUMERALS
[0034] 1 unit housing
[0035] 5 motor stator
[0036] 9 pump chamber
[0037] 10 pump outer rotor
[0038] 11 pump inner rotor
[0039] 13 permanent magnet
[0040] 14 motor rotor
[0041] 15 permanent magnet holding portion
[0042] 16 back yoke
[0043] 18 oil suction port
[0044] 19 oil discharge port
* * * * *