JP2012026309A - Electric pump unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric pump unit achieving reduction in weight and compactness, and preventing temperature rise of a component on a substrate of a controller.SOLUTION: In the electric pump unit, a pump housing 2 of a pump 1 sucking and discharging oil, a motor housing 4 having a built-in electric motor 3 for driving the pump, and a controller 5 controlling the electric motor 3 are integrally provided. An annular substrate 31 of the controller 5 is disposed between the pump housing 2 and the motor housing 4, and at least part of a component 32 attached to the substrate 31 is attached to the pump housing 2 side.

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, 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).

  In such a conventional electric pump unit, the pump housing constituting the pump and the motor housing incorporating the electric motor are connected to each other, and the controller board is fixed to the end surface of the motor opposite to the pump housing. A plurality of electrical components (electrical components and electronic components) such as capacitors and FETs constituting the controller are attached to the substrate. The motor housing is usually made of a metal such as an aluminum alloy, and has a peripheral wall portion that accommodates the motor and a lid (end wall portion) that closes the end portion, and the motor and the substrate are accommodated in the peripheral wall portion. Later, the lid was fixed to the end of the peripheral wall.

JP 2008-215088 A

  The electric pump unit for an automobile is disposed in the engine room of the automobile, and the temperature of the component rises due to the heat generated by the stator coil of the motor and the self-heating of the component on the board of the controller.

  In recent years, in order to reduce the weight and cost of the electric pump unit, it has been proposed that the motor housing be made of a synthetic resin. However, in this case, there is a problem that the heat dissipation effect is lowered. Even if the motor housing is made of synthetic resin, for the same reason as described above, it is necessary to separate the peripheral wall portion constituting the motor housing and the lid and fix or join them later. In addition, since the substrate is arranged on the motor side where the heat is high, the temperature of the component is increased by receiving heat from the motor, and the heat resistance of the component may be exceeded due to difficulty in radiating heat. In particular, the capacitor is tall and is arranged on the motor side of the board in order to achieve compactness. However, if this is done, it will receive heat from the motor and is difficult to dissipate, so it may become very hot.

  An object of the present invention is to provide an electric pump unit capable of solving the above-described problems, reducing the weight and size, and preventing the temperature rise of components on a controller board.

  An electric pump unit according to the present invention includes a pump housing for a pump that sucks and discharges oil, a motor housing that incorporates an electric motor for driving a pump, and a controller that controls the electric motor. The annular substrate is disposed between the pump housing and the motor housing, and at least a part of the components attached to the substrate is attached to the pump housing side.

  The pump housing is usually made of a metal such as an aluminum alloy, has a large heat capacity, and has a large surface area. In addition, since oil below a certain temperature (for example, 110 ° C.) flows through the pump housing, the temperature rise is small. The controller's annular board is placed between the pump housing and the motor housing, and at least some of the parts attached to the board face the pump housing, so the heat from these parts is effectively dissipated and temperature rise is prevented Is done.

  For example, the substrate is fixed to a pump housing or a motor housing. For example, a substrate fixed to the pump housing is brought into contact with the motor housing, or a substrate fixed to the motor housing is brought into contact with the pump housing.

  When the pump housing and the motor housing are integrated, the motor shaft of the electric motor housed in the motor housing enters the pump housing and is connected to the pump. Since the substrate of the controller is annular, the motor shaft and the structure for supporting it can be positioned inside the substrate.

  The components arranged on the pump housing side are, for example, those having low heat resistance. For example, a capacitor, FET or the like is attached to the pump housing side of the substrate.

  For example, at least some components attached to the substrate are brought into contact with the pump housing directly or via a heat transfer member.

  If it does in this way, the heat dissipation effect can be heightened more.

  As the heat transfer member, for example, a thermosetting viscoelastic resin having a high thermal conductivity such as silicone rubber, a heat radiating sheet, or the like is used. When using a thermosetting viscoelastic resin, for example, after applying the resin to the pump housing, the substrate is assembled to the pump housing so that the components are pressed against the resin, and the resin is cured. If it does in this way, resin should just be apply | coated to a little thicker than the space | interval of a pump housing and components, and dimension management is easy.

  For example, at least some of the components attached to the substrate are placed in a recess formed in the end face of the pump housing that faces the substrate.

  The part put into the recess is a tall part such as a capacitor.

  In this way, the surface area of the pump housing that faces the component is increased, and the heat dissipation effect is further increased. In addition, the distance between the substrate and the pump housing can be reduced by the amount of the recess, and the size can be reduced.

  In this case as well, it is preferable that the component is brought into contact with the pump housing directly or via a heat transfer member. For example, after applying the thermosetting viscoelastic resin as described above into the recess, the component is placed in the recess so as to be pressed against the resin, and the substrate is assembled to the pump housing.

  Thus, since the heat dissipation effect of components is high, the motor housing can be made of synthetic resin. Furthermore, since the controller board is disposed on the pump housing side of the motor, the peripheral wall portion and the end wall portion of the motor housing can be formed integrally. Moreover, the stator which comprises a motor can also be integrally molded with the surrounding wall part of the motor housing made from a synthetic resin. In this way, the overall weight and size can be reduced.

  According to the electric pump unit of the present invention, as described above, it is possible to effectively dissipate the components on the board of the controller, and it is possible to reduce the weight and size, and to prevent the temperature of the components from rising. .

FIG. 1 is a longitudinal sectional view of a main part of an electric pump unit for transmission 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 a main part of an electric pump unit for transmission showing an embodiment of the present invention. In the following description, the left side of FIG. 1 is the front, the right side is the rear, and the left and right when viewed from the front are the left and right.

  The electric pump unit includes a pump housing (2) of a pump (1) that sucks and discharges oil, a motor housing (4) that incorporates an electric motor (3) for driving the pump, and a controller that controls the electric motor (3) ( 5) is provided integrally. In this example, the pump (1) is an internal gear pump, and the motor (3) is a sensorless control brushless DC motor having a three-phase winding.

  The pump housing (2) includes a front half (pump plate) (6) and a rear half (7) (pump housing). The front half (6) is plate-shaped. The rear half (7) has a thick short cylindrical shape in which the rear wall (7b) is integrally formed at the rear end of the peripheral wall (7a) and the front is open. The front end face of the peripheral wall (7a) of the rear half (7) is fixed to the rear end face of the front half (6) via an O-ring (8). The motor housing (4) has a thick cylindrical shape in which the rear end wall (4b) is integrally formed at the rear end of the peripheral wall (4a) and the front is open, and the front end surface of the peripheral wall (4a) is the rear. It is fixed to the rear end face of the side half (7) via a seal member (9). In this example, both halves (6) and (7) of the pump housing (2) and the peripheral wall portion (4a) of the motor housing (4) are fixed to each other by a plurality of bolts (10). Both halves (6) and (7) of the pump housing (2) are made of metal such as aluminum alloy. The motor housing (4) is made of synthetic resin.

  A pump chamber (11) having a circular cross section is formed on the front surface of the rear half (7) in the pump housing (2). An outer gear (outer rotor) (12) is rotatably accommodated in the pump chamber (11), and an inner gear (inner rotor) (13) meshing with the outer gear (12) is rotatably disposed inside the outer gear (12). An oil suction port (14) and an oil discharge port (15) communicating with the pump chamber (11) are formed in the front half (6) of the pump housing (2). A circular hole (16) communicating with the pump chamber (11) is formed at the center of the rear wall (7b) of the rear half (7) of the pump housing (2), and protrudes rearward around the periphery thereof. The support cylindrical portion (17) is integrally formed.

  A connector (18) is integrally formed on the outer peripheral surface of the front portion of the peripheral wall (4a) of the motor housing (4).

  The motor (3) includes a pump drive motor shaft (19) extending in the front-rear direction, a motor rotor (20) fixed to the rear portion of the motor shaft (19), and a motor stator (21) disposed around the motor rotor (20). ).

  The stator (21) is an insulator (synthetic resin insulator) (23) incorporated in a core (22) made of laminated steel sheets, and a stator coil (24) is wound around the insulator (23). . The stator (21) is molded integrally with the peripheral wall (4a) of the motor housing (4), and the inner peripheral surface of the core (22) is exposed to the inner periphery of the peripheral wall (4a). Although not shown, the coil (24) is connected to the connector.

  A portion near the rear end of the motor shaft (19) is cantilevered rotatably by a bearing device (25) provided on a support cylindrical portion (17) of the rear half (7). In this example, the bearing device (25) includes two ball bearings (26) which are adjacent to the front and rear, and the inner ring (26a) of each bearing (26) is fixed to the motor shaft (19). The outer ring (26b) is fixed to the support cylindrical portion (17). The front part of the motor shaft (19) passes through the hole (16) part of the rear half (7) and enters the pump chamber (11), and its front end is connected to the inner gear (13). Yes. A seal (27) is provided between a portion of the support cylindrical portion (17) in front of the bearing device (25) and the motor shaft (19).

  In the motor rotor (20), a synthetic resin permanent magnet holding member (29) is fixedly provided on the outer periphery of a cylindrical rotor body (back yoke) (28), and the holding member (29) is equally divided in the circumferential direction. The segment-shaped permanent magnet (30) is held at a plurality of locations. The rotor body (28) is, for example, a metal sintered body, and is integrally formed on the flange (28a) fixed to the rear end of the motor shaft (19) and the outer peripheral edge of the flange (28a). A cylindrical portion (28b) extends forward from the inside of the stator (21) so as to surround the shaft (19). A small diameter portion (19a) formed at the rear end of the motor shaft (19) is press-fitted into a hole (37) formed at the center of the flange portion (28a) of the rotor body (28).

  The axial position of the center of gravity of the rotating part including the motor shaft (19), the rotor (20), and the inner gear (13) of the pump (1) is within the axial range of the bearing device (25). In this example, the axial position of the center of gravity is between the two ball bearings (26) constituting the bearing device (25).

  The substrate (31) of the controller (5) is a perforated disc-shaped annular substrate, and is disposed between the pump housing (2) and the motor housing (4). The board (31) is arranged around the support cylindrical part (17) of the rear half (7), and is fixed to the front face of the peripheral wall part (4a) of the motor housing (4) by screws or the like (not shown). The motor shaft (19) passes through the inside of the substrate (31). The substrate (31) is in contact with the rearward surface of the rear wall (7b) of the rear half (7). An electrical component (32) constituting the controller (5) is mounted on the substrate (31). In the drawing, only one capacitor attached to the front surface of the substrate (31) is shown as the component (32), but a plurality of components are mounted at appropriate locations on the front surface of the substrate (31). The component may also be mounted on the rear surface of the substrate (31). A circular recess (33) is formed on the rear surface of the front half (6) of the pump housing (2) corresponding to the component (32), and a circular protrusion (34) formed on the front surface of the rear half (7). Is closely fitted in the recess (33). A tapered hole-like concave portion (35) reaching the inside of the convex portion (34) is formed on the rear surface of the rear half (7) corresponding to the convex portion (34). The component (32) on the substrate (31) enters the recess (35). The O-ring (8) between the two halves (6) and (7) is eccentric with respect to the center of the pump chamber (11), and the recesses (33) of the pump chamber (11) and the halves (6) and (7) (33) ) And the convex portion (34) are located inside the O-ring (8).

  A circular hole (38) is formed in the center of the rear end wall (4b) of the motor housing (4), and the vent filter (39) is disposed on the rear surface of the rear end wall (4b) so as to close the hole (38). It is fixed to. The inner diameter of the hole (38) is larger than the inner diameter of the hole (37) of the rotor body (28).

  The pump housing (2) is made of metal, has a large heat capacity, and has a large surface area. In addition, since the oil below a certain temperature flows through the pump housing (2), the temperature rise is small. Since the board (31) of the controller (5) is arranged between the pump housing (2) and the motor housing (4), and the component (32) on the board (31) faces the pump housing (2), The heat of the component (32) is effectively dissipated and temperature rise is prevented. Since the recess (35) is formed in the pump housing (2) and its surface area is increased, the heat dissipation effect is further enhanced. Since the component (32) enters the recess (35) formed in the pump housing (2) and faces the pump housing (2) over a wide area, heat is radiated more effectively. In addition, the concave part (35) absorbs the axial length of the tall part (32), and even if the substrate (31) is placed between the pump housing (2) and the motor housing (4), the entire unit The dimension in the axial direction is not increased.

  Preferably, a part of the part (32) is in direct contact with the pump housing (2). Further, a part of the component (32) may indirectly contact the pump housing (2) via the heat transfer member. If it does in this way, the heat dissipation effect can be heightened more. As the heat transfer member, for example, a thermosetting viscoelastic resin having a high thermal conductivity such as silicone rubber, a heat radiating sheet, or the like is used. When a thermosetting viscoelastic resin is used, the heat transfer member (36) is filled in the recess (35) as indicated by an imaginary line (chain line) in the drawing. For example, after applying an appropriate amount of the heat transfer member (36) in the recess (35), the substrate (31) is fixed to the pump housing (2), and the component (32) is placed in the recess (35). The heat transfer member (36) is filled in the recess (35) by being brought into pressure contact with the heat member (36) and curing the heat transfer member (36) in this state. The surface area of the pump housing (2) may be increased to increase the surface area, thereby increasing the heat dissipation effect.

  In the pump housing (2), not only the recess (35) as described above, but also a hole that penetrates both halves (6) and (7) forward and backward, and the parts on the board (31) are inserted into this hole. You may make it let. In that case, the O-ring (8) is positioned inside the through hole.

  On the front surface of the substrate (31), not only capacitors but also low heat-resistant parts such as FETs are mounted, but for parts that are not tall, do not form a recess in the pump housing (2). The component may be opposed to the end surface of the pump housing (2). In that case also, the component is preferably brought into contact with the pump housing (2) directly or indirectly via a heat transfer member.

  The electric pump unit is assembled, for example, as follows.

  First, a positioning jig is fixed to the rear end wall (4b) of the motor housing (4) in a state where the vent filter (39) is not attached. The positioning jig is provided with a guide tube portion having a penetrating guide hole, and the guide tube portion extends forward through the hole (38) of the rear end wall portion (4b). A guide pin is inserted into the guide hole of the guide tube portion so as to move back and forth. The guide pin is biased forward by an elastic member such as a spring, and protrudes forward from the front end of the guide tube portion. Next, a guide pin is inserted into the hole (37) of the rotor body (28) to which the permanent magnet holding member (29) and the permanent magnet (30) are attached, and the motor rotor (20) is guided using the guide pin as a guide. It is moved rearward until it hits the front end of the cylindrical portion, and is incorporated inside the motor stator (21). Next, the small diameter portion (19a) of the motor shaft (19) to which the bearing device (25) is attached is inserted into the hole (37) of the rotor body (28) that is prevented from moving backward by the guide tube portion. Then, the guide pin is pushed into the hole (37) while pushing backward. Next, the substrate (31) is fixed to the peripheral wall portion (4a) of the motor housing (4), and soldering is performed on necessary portions. Next, the support cylindrical portion (17) of the rear half (7) to which the seal (27) is attached is fitted to the outside of the bearing device (25) on the motor shaft (19). At this time, if necessary, a heat transfer member such as a thermosetting viscoelastic resin is applied to the rear surface of the rear wall (7b) of the rear half (7) and the recess (35). Next, the inner gear (13) is fixed to the front end of the motor shaft (19), the outer gear (12) is assembled, the front half (6) is combined with the rear half (7), and both halves (6 ) (7) is fixed to the motor housing (4). When the assembly of the pump (1), the motor (3) and the substrate (31) is completed in this way, the jig is removed, and the outer periphery of the vent filter (39) is attached to the rear end wall of the motor housing (4). It is fixed by heat welding around (38) on the rear surface of the part (4b).

  While the vehicle is running, the motor (3) is stopped, and therefore the pump (1) is also stopped.

  While the vehicle is stopped, the motor (3) is operated, whereby the pump (1) is also operated. When the pump (1) is operated, the oil is sucked into the pump chamber (11) from the oil suction port (14) through the oil suction pipe (not shown) and discharged from the oil discharge port (15), and the oil discharge pipe (not shown). It is supplied to the required part of the transmission through.

  In the above electric pump unit, one axial direction of the motor shaft (19) is cantilevered by the bearing device (25), and the motor rotor (20) is provided so as to surround the outer periphery of the bearing device (25). Because of the structure, the length of the motor shaft (19) can be shortened, and further downsizing is possible. Further, since the axial position of the center of gravity of the rotating part including the motor shaft (19), the motor rotor (20) and the inner gear (13) of the pump (1) is within the axial range of the bearing device (25), the rotating part Can be stably rotated. Furthermore, since the position of the center of gravity is between the two ball bearings (26) constituting the bearing device (25), the rotating part can be rotatably supported more stably. Further, the bearing device (25) can be supported only by the cylindrical portion (17) formed integrally with the pump housing (2), and no other bearing device is required. For this reason, the number of parts can be further reduced, and further weight reduction and downsizing can be achieved.

  In the electric pump unit described above, since the substrate (31) is disposed between the pump housing (2) and the motor housing (4), the peripheral wall portion (4a) and the rear end wall portion (4b) of the motor housing (4) are arranged. ) Can be formed integrally. For this reason, the unit can be further downsized. Since the stator (21) of the motor (3) is molded integrally with the motor housing (4), it can be made more compact. Further, since the motor housing (4) is made of synthetic resin, the weight can be further reduced. However, the peripheral wall portion (4a) and the rear end wall portion (4b) of the motor housing (4) may not be formed integrally, and the stator (21) of the motor (3) is connected to the motor housing (4). It does not have to be molded integrally.

  In the above embodiment, the motor rotor (20) has a plurality of permanent magnets (30) on a synthetic resin permanent magnet holding member (29) fixedly provided on the outer peripheral portion of the cylindrical rotor body (28). Therefore, it is not necessary to fix the permanent magnet (30) to the rotor body (29) with an adhesive, and there is no possibility of peeling.

  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.

(1) Pump
(2) Pump housing
(3) Electric motor
(4) Motor housing
(5) Controller
(31) Board
(32) Parts
(35) Recess
(36) Heat transfer member

Claims (3)

In an electric pump unit in which a pump housing for sucking and discharging oil, a motor housing incorporating a pump driving electric motor, and a controller for controlling the electric motor are integrally provided,
An electric pump unit, wherein an annular substrate of a controller is disposed between a pump housing and a motor housing, and at least a part of components attached to the substrate is attached to the pump housing side.   2. The electric pump unit according to claim 1, wherein at least some of the components attached to the substrate are brought into contact with the pump housing directly or via a heat transfer member.   3. The electric pump unit according to claim 1, wherein at least a part of the parts attached to the substrate is placed in a recess formed in an end surface of the pump housing facing the substrate.

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