JP2012197709A - Pump and electric pump unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pump capable of suppressing tilt of a pump rotor fixed to a distal end of a pump drive shaft during actuation.SOLUTION: In this pump 2, a pump chamber 10 demarcated by a first end wall 8a at one side in an axial direction and a second end wall 9a at the opposite side is formed in a pump body 5. A pump rotor 13 is fixed to a distal end of a pump drive shaft 16 positioned in the pump chamber 10 while penetrating through the first end wall 8a. Suction ports 30, 31 are formed on opposite surfaces of the first end wall 8a and the second end wall 9a at predetermined positions corresponding to the pump rotor 13. Discharge ports 32, 33 are formed on opposite surfaces of the first end wall 8a and the second end wall 9a at predetermined positions corresponding to the pump rotor 13. An extension groove extending from the discharge port 32 beyond the center of the pump drive shaft 16 toward the suction port 30 is formed at the first end wall 8a.

Description

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

  Hydraulic pressure is supplied to the vehicle's transmission by a hydraulic pump. However, in order to save energy, the vehicle is stopped when the vehicle is stopped, so-called idle stop (idling stop) is secured. In order to do so, an electric hydraulic pump is used.

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

  FIG. 1 shows the overall configuration of such a conventional electric pump unit.

  The electric pump unit is a unit housing (1) in which a pump (2) and an electric motor (3) for rotationally driving the pump (2) are integrated. 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 body (5), a motor housing (6), and a lid (7).

  The pump body (5) includes a rear pump housing (8) and a front pump plate (9). The pump housing (8) has a thick plate shape that extends in a direction perpendicular to the front-rear direction, and a pump chamber (10) having an open front is formed at the center thereof. A pump plate (9) is fixed to the front surface of the pump housing (8) via an O-ring (11), and the front surface of the pump chamber (10) is closed. The pump housing (8) on the rear side of the pump chamber (10) is the first end wall (8a) that defines the pump chamber (10), and the pump plate (9) that closes the pump chamber (10) is the pump It becomes the 2nd end wall (9a) which divides a chamber (10). An outer gear (12), which is an outer pump rotor, is rotatably accommodated in the pump chamber (10), and an inner gear (13), which is an inner pump rotor that meshes with the outer gear (12), is disposed inside the outer gear (12).

  The motor housing (6) has a cylindrical shape, and its front end is fixed to a portion near the outer periphery of the rear surface of the pump housing (8) via a seal member (14). The rear end opening of the motor housing (6) is closed by the lid (7). The pump housing (8), the motor housing (6), and the lid (7) form a waterproof space for housing the electric motor (3) and the controller (4).

  A cylindrical portion (8b) having a smaller diameter than the motor housing (6) is integrally formed at the center of the rear end surface of the pump housing (8), and the bearing device (15) provided at the rear portion in the cylindrical portion (8b) A motor shaft (16) that is a pump drive shaft extending in the front-rear direction is cantilevered. In this example, the bearing device (15) includes two ball bearings (17) that are adjacent to the front and rear, and the inner ring (17a) of each bearing (17) is fixed to the motor shaft (16). The outer ring (17b) is fixed to the cylindrical portion (8b). The front part of the motor shaft (16) passes through the hole (18) formed in the first end wall (8a) of the pump housing (8) and enters the pump chamber (10), and the front end The inner gear (13) is fitted and fixed to the portion. An oil seal (19) is provided between a portion of the cylindrical portion (8b) in front of the bearing device (15) and the motor shaft (16).

  A motor rotor (20) constituting the motor (3) is fixed to a rear end portion of the motor shaft (16) protruding rearward from the cylindrical portion (8b). The rotor (20) extends from the rear end of the motor shaft (16) in the radial direction and surrounds the outer periphery of the bearing device (15) on the outer peripheral portion of a cylindrical rotor body (21) with a synthetic resin permanent magnet holding member ( 22) is provided in a fixed shape, and segment-shaped permanent magnets (23) are held at a plurality of locations equally dividing the holding member (22) in the circumferential direction. The axial position of the center of gravity of the rotating portion including the motor shaft (16), the rotor (20), and the inner gear (13) of the pump (2) is within the axial range of the bearing device (15). In this example, the axial position of the center of gravity is between the two ball bearings (17) constituting the bearing device (15).

  A motor stator (24) constituting the motor (3) is fixedly provided on the inner periphery of the motor housing (6) facing the rotor (20). The stator (24) is an insulator (synthetic resin insulator) (26) incorporated in a core (25) made of laminated steel plates, and a stator coil (27) is wound around the insulator (26). . In this example, the stator (24) is fixed to the inner periphery of the motor housing (6) by an appropriate means such as adhesion on the outer periphery of the core (25).

  The board (28) of the controller (4) is fixed to the rear end of the insulator (26), and the component (29) constituting the controller (4) is attached to the board (28). The component is disposed at a predetermined position on at least one of the front surface and the rear surface of the substrate (28). In the drawing, one component (29) attached to the rear surface of the substrate (28) is shown.

  Opposing surfaces of the first end wall (8a) and the second end wall (9a) corresponding to the meshing part (in this example, the lower meshing part) of the inner gear (13) and the outer gear (12) of the pump (2) Further, arc-shaped suction ports (30) and (31) are formed. An arc-shaped discharge port is formed on the opposed surfaces of the first end wall (8a) and the second end wall (9a) corresponding to the meshing portion (in this example, the upper meshing portion) of the inner gear (13) and the outer gear (12). (32) and (33) are formed. The pump plate (9) is formed with a suction hole (34) communicating with the suction port (31) and a discharge hole (35) communicating with the discharge port (33). A relief groove (36) is formed in the first end wall (8a) to communicate the hole (18) and the suction port (30).

  FIG. 2 is a view showing the opposed surfaces of the first end wall (8a) and the second end wall (9a) with the pump housing (8) in FIG. 1 opened on the right side and the pump plate (9) opened on the left side. It is. In FIG. 2, (12a) indicates the pitch circle of the outer gear (12), and (13a) indicates the pitch circle of the inner gear (13).

  As shown in FIG. 2, the shapes of the suction ports (30) and (31) are the same, and their areas are substantially equal to each other. Further, the shapes of the discharge ports (32) and (33) are the same, and their areas are substantially equal to each other. The areas of the discharge ports (32) and (33) facing the inner gear (13) are also substantially equal to each other.

JP 2010-207075 A

  When the pump (2) is driven by the electric motor (3) and the inner gear (13) and the outer gear (12) rotate, the suction ports (30) and (31) are at low pressure and the discharge ports (32) and (33) are Become high pressure. The area where both discharge ports (32) (33) are opposed to the inner gear (13), i.e., the pressure receiving area where the inner gear (13) receives pressure from each discharge port (32) (33) is substantially equal to each other. 32) The force that the inner gear (13) receives from the front and rear in the portions of (33) and (33) is almost balanced. On the other hand, during the operation of the pump (2), the oil in the meshing part of the inner gear (13) and the outer gear (12) also becomes high pressure at the part corresponding to the discharge port (32) (33), thereby the inner gear (13). Receives a force in a direction away from the outer gear (12) (downward in this example). Since the front side portion of the motor shaft (16) to which the inner gear (13) is fixed is cantilevered, the downward force causes the front end of the motor shaft (16) to elastically deform downward, resulting in the inner gear ( 13) is inclined such that the upper side corresponding to the discharge ports (32) and (33) is forward and the lower side corresponding to the suction ports (30) and (31) is rearward. For this reason, the upper front side of the inner gear (13) rotates in contact with the second end wall (9a), and the lower rear side of the inner gear (13) contacts the first end wall (8a) to generate noise. However, there is a problem that the inner rotor (13) and both end walls (8a) and (9a) are worn, and foreign matter is generated and mixed into the oil.

  An object of the present invention is to provide a pump and an electric pump unit that can solve the above-described problems and can suppress the tilt of a pump rotor fixed to the tip of a pump drive shaft during operation.

  In the pump according to the present invention, a pump chamber defined by a second end wall opposite to the first end wall on one side in the axial direction is formed in the pump body, and passes through the first end wall to pass through the pump chamber. The pump rotor is fixed to the tip of the pump drive shaft located at a position where a suction port is formed on the opposing surfaces of the first end wall and the second end wall at predetermined positions corresponding to the pump rotor, and the pump rotor In the pump in which the discharge port is formed on the opposing surfaces of the first end wall and the second end wall at the corresponding predetermined positions, the discharge port extends from the center of the pump drive shaft to the suction port side on the first end wall. It is characterized by the formation of extended extended grooves.

  During the operation of the pump, the pump rotor fixed to the tip of the pump drive shaft receives a radial force by the high pressure oil at the portion corresponding to the discharge port that becomes high pressure. For this reason, the pump rotor is inclined in a direction in which the high pressure discharge port side approaches the second end wall side and the low pressure suction port side approaches the first end wall side. On the other hand, part of the oil in the high-pressure discharge port enters the extended groove of the first end wall, and a pressure is generated that pushes the pump rotor toward the second end wall at the extended groove portion on the suction port side. . This pressure acts in a direction to suppress the inclination of the pump rotor. As a result, the inclination of the pump rotor is small, and noise, wear of the pump rotor and both end walls, and generation of foreign matter are reduced.

  For example, the width of the extension groove is larger than the center of the pump drive shaft on the suction port side and on the discharge port side.

  In this case, the pressure receiving area where the pump rotor receives pressure from the extended groove toward the second end wall is larger on the suction port side. Therefore, the force for suppressing the tilt of the pump rotor is increased, and the tilt of the pump rotor is further decreased.

  For example, two extended grooves extend from the discharge port to the suction port side on both sides of the center of the pump drive shaft.

  In this case, the pressure of the oil in the extension groove that suppresses the inclination of the pump rotor is balanced on both sides of the center of the pump drive shaft, and the inclination of the pump rotor in the direction orthogonal to the inclination direction is small.

  For example, a pump is an internal gear pump in which an inner gear that rotates in mesh with an outer gear is arranged inside an outer gear that is rotatably accommodated in a pump chamber, and a pump rotor that is fixed to the tip of a pump drive shaft is provided. It is an inner gear.

  Also in this case, as described above, the inclination of the inner gear during operation of the pump is suppressed, and noise, wear of the inner gear and both end walls, and generation of foreign matter are reduced.

  For example, the pump body includes a pump housing in which a pump chamber is formed, and a pump plate that is fixed to the pump housing and closes the pump chamber, and the pump drive shaft passes through the pump housing and enters the pump chamber. . In that case, the pump housing side is the first end wall and the pump plate side is the second end wall.

  The electric pump unit according to the present invention includes the pump according to the present invention, and is characterized in that a motor driving electric motor for driving a pump driving shaft is provided in a motor housing connected to the pump body.

  According to the pump and the electric pump unit of the present invention, as described above, the tilt of the pump rotor fixed to the tip end portion of the pump drive shaft can be suppressed during the operation of the pump. In addition, wear on both end walls and generation of foreign matter can be reduced.

FIG. 1 is a longitudinal sectional view of an electric pump unit showing a conventional example. FIG. 2 is an end view of the pump housing and pump plate of FIG. FIG. 3 is a drawing corresponding to FIG. 2 showing an embodiment of the present invention.

  Hereinafter, an embodiment in which the present invention is applied to an electric pump unit used for a hydraulic pump of an automobile will be described with reference to FIG.

  FIG. 3 is an end view of the pump housing (8) and the pump plate (9) corresponding to FIG.

  The configuration of the electric pump unit in this embodiment is the same as that of the conventional example of FIG. 1 except for the configuration of the discharge port (32) on the first end wall (8a) side.

  As shown in FIG. 3, two extended grooves (37) extending from the discharge port (32) to the suction port (30) side from the center of the motor shaft (16) are formed on the first end wall (8a). Yes. The two extension grooves (37) are located on both sides of the center of the motor shaft (16), extending from the portion near the both ends of the discharge port (32), and are almost symmetrical with respect to the center of the motor shaft (16). ing. A wide portion (37a) is formed at the distal end portion on the suction port (30) side of each extension groove (37), and the width of each extension groove (37) is the discharge port (32) on the suction port (30) side. It is larger than the) side.

  During operation of the pump (2), the inner gear (13) receives a downward force due to the high pressure oil in the meshing part of the inner gear (13) and the outer gear (12), and the upper side corresponding to the discharge ports (32) (33) The front side is inclined so that the lower side corresponding to the suction ports (30) and (31) is the rear side. On the other hand, a part of the oil in the high-pressure discharge port (32) enters the extension groove (37) of the first end wall (8a), and in the extension groove (37) side of the suction port (30) side, A pressure is generated to push the inner gear (13) forward. This pressure acts in a direction to suppress the inclination of the inner gear (13). As a result, the inclination of the inner gear (13) is small, and noise, wear of the pump rotor and both end walls, and generation of foreign matter are reduced. In the wide part (37a) on the suction port (30) side of each extension groove (37), a larger force is generated than the other part of the extension groove (37), and the force that suppresses the inclination of the inner gear (13) described above. Is larger and the inclination of the inner gear (13) is smaller. Furthermore, since the two extension grooves (37) extend from the discharge port (32) to both sides of the center of the motor shaft (16) to the suction port (30) side, the extension grooves that suppress the inclination of the inner gear (13). The pressure of the oil in (37) is balanced on both sides of the center of the motor shaft (16), and the inclination of the inner gear (13) in the direction orthogonal to the inclination direction is small.

  During the operation of the pump (2), part of the oil in the discharge port (32) enters the hole (18) from between the first end wall (9a) and the inner gear (13), but the hole (18) Since the inside of the cylinder communicates with the low-pressure suction port (30) by the escape groove (36), the oil in the hole (18) does not become high pressure. For this reason, oil does not leak through the oil seal (19) to the bearing device (15) side.

  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. Further, the configuration of the pump (2) is not limited to that of the above embodiment, and can be changed as appropriate.

  Moreover, this invention is applicable also to electric pump units other than the electric pump unit for motor vehicles, and pumps other than an electric pump unit.

(2) Pump
(3) Electric motor
(5) Pump body
(6) Motor housing
(8) Pump housing
(8a) First end wall
(9) Pump plate
(9a) Second end wall
(10) Pump room
(12) Outer gear
(13) Inner gear (pump rotor)
(16) Motor shaft (pump drive shaft)
(30) (31) Suction port
(32) (33) Discharge port
(37) Extension groove
(37a) Wide part

Claims (5)

A pump chamber defined by a second end wall opposite to the first end wall on one side in the axial direction is formed in the pump body, and passes through the first end wall to be located in the pump chamber. A pump rotor is fixed to the front end of the first end, a suction port is formed on the opposing surfaces of the first end wall and the second end wall at a predetermined position corresponding to the pump rotor, and a first position at a predetermined position corresponding to the pump rotor is formed. In the pump in which the discharge port is formed on the opposing surface of the end wall of 1 and the second end wall,
An extension groove formed on the first end wall from the discharge port to the suction port side from the center of the pump drive shaft.   2. The pump according to claim 1, wherein the width of the extension groove is larger on the suction port side than on the pump drive shaft and on the discharge port side.   The pump according to claim 1 or 2, wherein the two extension grooves extend from the discharge port to both sides of the center of the pump drive shaft toward the suction port side.   It is an internal gear pump in which an inner gear that rotates in mesh with the outer gear is arranged inside an outer gear that is rotatably accommodated in the pump chamber, and the pump rotor fixed to the tip of the pump drive shaft is an inner gear. The pump according to any one of claims 1 to 3, characterized in that A pump according to any one of claims 1 to 4,
An electric pump unit characterized in that a motor driving electric motor for driving a pump driving shaft is provided in a motor housing connected to the pump body.

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