JP2012026349A - Electric pump unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact electric pump unit with high reliability which can reduce the number of parts.SOLUTION: The electric pump unit includes: a pump 2 sucks in and discharges oil when a rotor 14 arranged in a pump chamber 12 of a pump housing 5 rotates in slide contact with axial both end walls 12b and 12c; and a pump driving electric motor 3 having a motor shaft 20 connected to the rotor 14 of the pump 2. The motor shaft 20 is supported in a sliding rotation manner by a sliding bearing 17 of the pump housing 5, and a seal member 19 is provided across the sliding bearing 17 between the pump chamber 12 and the pump housing 5 opposite to the pump chamber 12, and the motor shaft 20. The tip of the motor shaft 20 is connected to a through-hole 26 of the rotor 14, and the tip surface of the motor shaft 20 is exposed inside the pump chamber 12. In the motor shaft 20, an axial first oil passage 32 reaching the inside of the sliding bearing 17 from the tip surface and a radial second oil passage 33 reaching the outer peripheral surface of the motor shaft 20 inside the sliding bearing 17 from the first oil passage 32 are formed.

Description

  The present invention relates to an electric pump unit used as a hydraulic pump for supplying hydraulic pressure to a transmission (transmission) of an automobile, for example.

  Oil pressure is supplied to the vehicle's transmission by a hydraulic pump, but for vehicles that perform so-called idle stop (idling stop) that stops the engine when the vehicle is stopped from the standpoint of energy saving, etc., ensure that the hydraulic pressure is supplied to the transmission even during idle stop. In order to do so, an electric hydraulic pump is used.

  Since an electric hydraulic pump for an automobile transmission is mounted in a limited space of a vehicle body, it is required to be compact, and to be light and reduce costs. In order to meet such a demand, an electric pump unit in which a pump and an electric motor for driving a pump are incorporated in a common unit housing has been proposed (for example, see Patent Document 1).

JP 2009-019522 A

  In the conventional electric pump unit as described above, an internal gear pump is usually used as the pump, and the motor shaft of the electric motor connected to the pump is provided by two rolling bearings arranged in the unit housing. Rotation is supported.

  For this reason, there are problems that the number of parts is large and the unit becomes large.

  An object of the present invention is to provide an electric pump unit that solves the above-described problems, can reduce the number of parts, and can be downsized, and has high reliability.

  An electric pump unit according to the present invention is connected to a pump that sucks and discharges oil by rotating a rotor disposed in a pump chamber of a pump housing in sliding contact with both axial end walls of the pump chamber, and the rotor of the pump. An electric pump unit having a pump drive electric motor having a motor shaft, wherein the motor shaft is slidably supported by the slide bearing portion of the pump housing, and the pump housing opposite to the pump chamber across the slide bearing portion; A seal member is provided between the motor shafts, the tip of the motor shaft is connected to the through hole of the rotor, the tip surface of the motor shaft is exposed in the pump chamber, and the motor shaft slides from the tip surface. A first oil passage in the axial direction reaching the inside of the bearing portion, and a second oil in the radial direction reaching the outer peripheral surface of the motor shaft inside the sliding bearing portion from the first oil passage. It is characterized in that the road is formed.

  Since a plain bearing is used in place of the conventional two rolling bearings, the number of parts can be reduced and the unit can be downsized. When the pump is driven by the electric motor, a part of the oil in the pump chamber that has become high pressure enters the through hole of the rotor from between the end wall of the pump chamber and the end surface of the rotor that is in sliding contact with the first chamber. It flows through the passage in the axial direction and is supplied to the sliding bearing portion through the second oil passage by centrifugal force. Since the slide bearing portion is lubricated by this oil, seizure does not occur and reliability is high even if a slide bearing is used.

  According to the electric pump unit of the present invention, as described above, the number of parts can be reduced and the size can be reduced, and the reliability is high.

FIG. 1 is a longitudinal sectional view of an electric pump unit showing an embodiment of the present invention.

  Hereinafter, an embodiment in which the present invention is applied to an electric pump unit for an automobile transmission will be described with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of the electric pump unit. In the following description, the left side of the drawing is the front and the right side is the rear.

  The electric pump unit is a unit housing (1) in which a pump (2) and a pump driving electric motor (3) are integrated. In this example, the controller (4) of the motor (3) is also incorporated in the housing (1). In this example, the pump (2) is an internal gear pump, and the motor (3) is a sensorless control DC brushless motor having a three-phase winding.

  The unit housing (1) includes a pump housing (5), a motor housing (6), and a lid (7).

  The pump housing (5) includes a front half (pump plate) (8) and a rear half (pump housing) (9). The front half (6) is plate-shaped. The rear half (9) has a thick cylindrical shape in which the rear wall (9b) is integrally formed at the rear end of the peripheral wall (9a) and the front part is open, and the peripheral wall of the rear half (9) The front end surface of the portion (9a) is fixed to the rear end surface of the front half (8) via an O-ring (10).

  The motor housing (6) has a cylindrical shape, and its front end is fixed to a portion of the rear half (9) near the outer periphery of the rear surface via a seal member (11). The rear end opening of the motor housing (6) is closed by the lid (7).

  A pump chamber (12) having a circular cross section is formed in front of the rear half (9) closed by the front half (8) of the pump housing (5). The pump chamber (12) is partitioned by a peripheral wall (12a), a front end wall (12b), and a rear end wall (12c). An outer rotor (outer gear) (13) is rotatably accommodated in the pump chamber (12), and an inner rotor (inner gear) (14) meshing with the inner rotor (13) is rotatably disposed inside the outer rotor (13). The outer rotor (13) rotates in sliding contact with the peripheral wall (12a) and the front and rear end walls (12b) (12c) of the pump chamber (12). The outer peripheral part of the inner rotor (14) rotates in sliding contact with the front and rear end walls (12b) (12c) of the pump chamber (12), and the inner peripheral part of the inner rotor (14) and the front and rear end walls (12b) ( There is a slight gap between 12c). Although not shown, the front half (8) is provided with an oil inlet and an oil outlet that communicate with the pump chamber (12).

  A circular hole (15) communicating with the pump chamber (12) is formed at the center of the rear wall (9b) of the rear half (9) of the pump housing (5), and protrudes rearward around the periphery thereof. The support cylindrical portion (16) is integrally formed. The bearing metal (18) constituting the sliding bearing portion (17) is fixed to the inner periphery of the support cylindrical portion (16), and an oil seal ( The seal member (19) is fixed.

  The motor (3) includes a pump drive motor shaft (20) extending in the front-rear direction, a motor rotor (21) fixed to the rear portion of the motor shaft (20), and a motor stator (22) arranged around the motor rotor (21). ).

  The stator (22) is an insulator (synthetic resin insulator) (24) incorporated in a core (23) made of laminated steel plates, and a stator coil (25) is wound around the insulator (24). . In this example, the stator (22) is fixed to the inner periphery of the motor housing (6) by appropriate means such as adhesion.

  The motor shaft (20) is inserted into the support cylindrical portion (16) of the rear half (9), and an intermediate portion thereof is rotatably supported by the slide bearing portion (17). The front part of the motor shaft (20) passes through the hole (15) part of the rear half (9) and enters the pump chamber (12), and the front end part of the inner rotor (14) extends in the front-rear direction. It is fixed by press-fitting into a through-hole (26) that penetrates through. The oil seal (19) is located on the opposite side of the pump chamber (12) with the slide bearing (17) in between, and the support cylinder (16) and the motor shaft (20) on the rear side of the slide bearing (17). It is sealed between.

  The motor rotor (21) is provided with a synthetic resin permanent magnet holding member (28) fixed on the outer periphery of the cylindrical rotor body (27), and is divided into a plurality of locations that equally divide the holding member (28) in the circumferential direction. A segment-shaped permanent magnet (29) is held. The rotor body (27) is, for example, a metal sintered body, and is integrally formed on the flange portion (27a) fixed to the rear end portion of the motor shaft (22) by press-fitting and the outer peripheral edge of the flange portion (27a). A cylindrical portion (27b) extends forward from the inside of the stator (22) so as to surround the motor shaft (20).

  The board (30) of the controller (3) is fixed to the rear end of the insulator (24) of the stator (22), and the component (31) constituting the controller (4) is attached to the board (30). Although the component is located at a predetermined position on at least one of the front surface and the rear surface of the substrate (30), the drawing shows one component (31) attached to the rear surface of the substrate (30).

  The front end surface of the motor shaft (20) is exposed in the pump chamber (12) from the through hole (26) of the inner rotor (14). A motor shaft (20) has a first oil passage (32) extending in the axial direction from the front end surface to the inside of the sliding bearing portion (17), and a motor inside the sliding bearing portion (17) from the first oil passage (32). A second oil passage (33) in the radial direction reaching the outer peripheral surface of the shaft (20) is formed. The first oil passage (32) may be one. Although the number and arrangement of the second oil passages (33) are arbitrary, it is preferable that the second oil passages (33) are radially formed at a plurality of locations in the front-rear direction and equally divided in the circumferential direction.

  While the automobile is running, the motor (3) is stopped, and therefore the pump (2) is also stopped.

  While the vehicle is stopped, the motor (3) operates, whereby the pump (2) also operates. When the pump (2) is operated, the oil is sucked into the pump chamber (12) from the oil suction port through an oil suction pipe (not shown) and discharged from the oil discharge port, and the required part of the transmission is passed through the oil discharge pipe (not shown). To be supplied.

  When the pump (2) is driven by the motor (3), the oil in the pump chamber (12) becomes high pressure. Part of this oil enters the through hole (26) of the inner rotor (14) from between the end wall (12b) of the pump chamber (12) and the end surface of the inner rotor (14) that is slidably in contact with the motor chamber (20). The first oil passage (32) flows in the axial direction and is supplied to the sliding bearing portion (17) through the second oil passage (33) by centrifugal force. Since this oil lubricates the sliding bearing portion (17), seizure does not occur. Even if oil is supplied to the slide bearing (17), an oil seal is provided between the support cylinder (16) opposite the pump chamber (12) and the pump shaft (20) across the slide bearing (17). Since (19) exists, the oil does not flow out of the pump housing (5), and the oil supplied to the slide bearing portion (17) returns to the pump chamber (12).

  The overall configuration of the electric pump unit and the configuration of each unit are not limited to those of the above-described embodiment, and can be changed as appropriate.

  Moreover, this invention is applicable also to electric pump units other than the electric pump unit for transmissions of a motor vehicle.

(2) Pump
(3) Electric motor
(5) Pump housing
(12) Pump room
(12b) (12c) End wall
(14) Inner rotor
(16) Slide bearing
(19) Oil seal
(20) Motor shaft
(26) Through hole
(32) 1st oil passage
(33) Second oil passage

Claims (1)

A pump disposed in the pump chamber of the pump housing slides in contact with both axial end walls of the pump chamber and rotates to suck and discharge oil, and a pump drive having a motor shaft connected to the pump rotor In an electric pump unit comprising an electric motor,
The motor shaft is slidably supported by the slide bearing portion of the pump housing, and a seal member is provided between the pump housing on the opposite side of the pump chamber and the motor shaft across the slide bearing portion, and the tip end of the motor shaft is the rotor. The front end surface of the motor shaft is exposed in the pump chamber, and the motor shaft has an axial first oil passage extending from the front end surface to the inside of the slide bearing portion, and a first oil passage from the first oil passage. An electric pump unit characterized in that a second oil passage in a radial direction reaching the outer peripheral surface of the motor shaft inside the sliding bearing portion is formed.

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