JP2012223030A - Electric motor and stator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stator for an electric motor that provides cooling for the stator and prevents a rise in temperature of the stator.SOLUTION: A stator 27 has stator coils 30 wound around a synthetic resin insulator 29 that covers a stator core 28. In the stator 27, bus bars 39 and 40 that are connected to the stator coils 30 are incorporated. Radiating portions 39d and 40c provided in the respective bus bars 39 and 40 are arranged on an outer side of the insulator 29 that covers an outer circumferential surface of the stator core 28.

Description

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

  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 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, a motor housing is connected to a pump body constituting the pump, and an electric motor and a controller are built in a sealed motor chamber formed in the motor housing. The electric motor is disposed on the pump body side in the motor chamber, and a controller board is fixed to the end surface of the electric motor on the side opposite to the pump body. A plurality of electrical components (electrical components and electronic components) such as capacitors and FETs constituting the controller are attached to the substrate.

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 stator rises due to heat generated by the stator coil of the electric motor, and the temperature of the controller components rises. In particular, parts such as electrolytic capacitors and FETs have their own heat generation and may exceed the limit temperature. In order to prevent this, the components are radiated by using heat radiation fins and heat radiating sheets. However, installation space for the heat radiating fins and heat radiating sheets is required, and the cost is increased.

  An object of the present invention is to provide an electric motor and a stator that can solve the above problems and cool the stator to prevent the temperature of the stator from rising.

  A stator according to the present invention is a stator in which a stator coil is wound around a synthetic resin insulator covering a stator core, and a bus bar connected to the stator coil is incorporated, and a heat radiating portion provided on the bus bar covers an outer peripheral surface of the stator core. It is arranged outside the insulator.

  The heat generated in the stator coil is transmitted to the heat radiating part through the bus bar and radiated from the heat radiating part to the outside. Thereby, the motor stator is cooled and its temperature rise is prevented.

  The heat dissipating part may be formed integrally with the bus bar, or may be made separately from the bus bar and fixed to the bus bar.

  For example, the outer periphery of an annular stator core is cut out, and the heat dissipating part of the bus bar is arranged outside the insulator that covers the outer peripheral surface of the cutout part.

  In this case, the outer dimension of the stator is not increased by the heat radiating portion of the bus bar arranged on the outer periphery of the stator core.

  For example, the insulator is formed integrally with a synthetic resin motor case, and the heat radiating portion of the bus bar is covered with a portion of the motor case located on the radially outer side of the stator core.

  In this case, the heat transmitted from the stator coil to the heat radiating portion of the bus bar is radiated to the outside through the portion of the motor case that covers it, and the stator coil is cooled. When the controller of the electric motor is also built in the motor case, the motor stator is cooled to prevent the temperature from rising, thereby preventing the temperature of the controller components from rising.

  The electric motor according to the present invention includes the stator according to the present invention.

FIG. 1 is a longitudinal sectional view of a main part of an electric pump unit showing an embodiment of the present invention. FIG. 2 is a cross-sectional view of the main part of the electric pump unit of FIG. FIG. 3 is a perspective view of a main part of the electric pump unit of FIG. FIG. 4 is an exploded perspective view showing the main part of the stator of the electric motor. FIG. 5 is a perspective view showing a first bus bar of the electric motor. FIG. 6 is a perspective view showing a second bus bar of the electric motor.

  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 the electric pump unit. In the following description, the left side of FIG.

  As shown in FIG. 1, the electric pump unit includes a pump (2) for sucking and discharging oil, an electric motor (3) for driving the pump, and a controller (4) for the electric motor (3) in the unit housing (1). ) Is integrated. 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) of the pump (2), and a motor housing (6) incorporating an electric motor (3) and a controller (4).

  The pump body (5) includes a rear pump housing (7) and a front pump plate (8). The pump housing (7) has a thick plate shape that extends in a direction orthogonal to the front-rear direction, and a pump chamber (9) having an open front is formed at the center thereof. A pump plate (8) is fixed to the front surface of the pump housing (7) via an O-ring (10), and the front surface of the pump chamber (9) is closed. An outer gear (11) is rotatably accommodated in the pump chamber (9), and an inner gear (12) that meshes with the inner gear (11) is disposed inside the outer gear (11). Although not shown, an oil suction port and an oil discharge port are formed in the pump housing (7) and the pump plate (8), and an oil suction hole and an oil communicating with the oil suction port are formed in the pump plate (8). An oil discharge hole communicating with the discharge port is formed. The pump housing (7) and the pump plate (8) are made of, for example, an aluminum alloy.

  The motor housing (6) includes a cylindrical synthetic resin motor case (13) and a disc-shaped lid (14) fixed to the rear end of the motor case (13). The front end of the motor case (13) is fixed to the rear surface of the pump housing (7) via an O-ring (15). The pump plate (8), the pump housing (7), and the motor case (13) include a plurality of connecting portions (8a), (7a), and (13a) that are integrally formed so as to protrude radially outward from the outer periphery thereof. The parts are secured to each other by bolts (16). The rear end opening of the motor case (13) is closed by the lid (14).

  A cylindrical portion (7b) having a smaller diameter than the motor case (13) is integrally formed at the center of the rear end surface of the pump housing (7), and the bearing device (17) provided at the rear portion in the cylindrical portion (7b) A motor shaft (18) extending in the front-rear direction is supported. In this example, the bearing device (17) is composed of two single row deep groove ball bearings (19) adjacent to the front and rear, and the inner ring (19a) of each bearing (19) is a motor shaft (18). The outer ring (19b) is fixed to the cylindrical portion (7b). In this example, the bearing (19) is a grease lubricated hermetically sealed bearing. The front part of the motor shaft (18) passes through the hole (21) formed in the rear wall of the pump housing (7) and enters the pump chamber (9), and the inner gear (12) Is fitted and fixed. An oil seal (22) is provided between a portion of the cylindrical portion (7b) in front of the bearing device (17) and the motor shaft (18).

  A motor rotor (23) constituting the motor (3) is fixed to a rear end portion of the motor shaft (18) protruding rearward from the cylindrical portion (7b). The rotor (23) extends from the rear end of the motor shaft (18) in the radial direction, and on the outer periphery of a cylindrical rotor body (24) surrounding the outer periphery of the bearing device (17), a permanent magnet holding member made of synthetic resin ( 25) is provided in a fixed shape, and segment-shaped permanent magnets (26) are held at a plurality of locations equally dividing the holding member (25) in the circumferential direction. The axial position of the center of gravity of the rotating part including the motor shaft (18), the rotor (23) and the inner gear (12) of the pump (2) is within the axial range of the bearing device (17). In this example, the axial position of the center of gravity is between the two ball bearings (19) constituting the bearing device (17).

  A motor stator (27) constituting the motor (3) is fixedly provided on the inner periphery of the motor case (13) facing the rotor (23). The stator (27) is an insulator (synthetic resin insulator) (29) incorporated in a stator core (28) made of laminated steel sheets, and a stator coil (30) is wound around the insulator (29). . In this example, the stator (27) is molded integrally with the inner periphery of the motor case (13).

  The board (31) of the controller (4) is fixed to the rear end of the insulator (29), and the component (32) constituting the controller (4) is attached to the board (31). Although only one component (32) attached to the front surface of the substrate (31) is shown in FIG. 1, the component is disposed at a predetermined position on at least one of the front surface and the rear surface of the substrate (31). The component (32) shown in FIG. 1 is, for example, an electrolytic capacitor.

  2 is a cross-sectional view showing a molded body of the motor case (13) and the stator (27) (a cross-sectional view viewed from the rear), FIG. 3 is a perspective view of the molded body from the rear, and FIG. It is a disassembled perspective view of the principal part of 27).

  As shown in detail in FIGS. 2 to 4, the core (28) is a pole protruding radially inward at a plurality of locations (six locations in this example) that equally divide the inner periphery of the annular portion (28a) in the circumferential direction. The portion (tooth portion) (28b) is integrally formed. The tip of each pole portion (28b) extends on both sides in the circumferential direction, and its inner peripheral surface forms one cylindrical surface. An insulator assembly space (33) is formed between adjacent pole portions (28b) on the inner periphery of the annular portion (28a). Although not shown in detail, the plurality of steel plates constituting the core (28) are stacked in the caulking portion (34) in the annular portion (28a) on the radially outer side of each pole portion (28b). It is fixed. The outer periphery of the annular portion (28a) of the core (28) has a shape in which the cylindrical surface is cut out at a plurality of locations corresponding to the pole portion (28b). A cutout portion on the outer periphery of the annular portion (28a) is indicated by reference numeral (35) in the drawing. The notch (35) is flat, and the outer periphery of the annular part (28a) has a polygonal shape.

  The insulator (29) is composed of a pair of front and rear halves (36, 37). Each half (36) and (37) is formed of a synthetic resin such as PPS (polyphenylene sulfide resin). Each half (36) (37) has an annular shape corresponding to the core (28), and is incorporated into the core (28) from both the front and rear sides. On the inner peripheral side of the front half (36), the front portion excluding the inner peripheral surface of the pole portion (28b) of the core (28) is fitted into the front half of the insulator mounting space (33) of the core (28). A coil mounting portion (36a) for covering is integrally formed. On the outer peripheral side of the front half (36), a flat plate-like rear protrusion (36b) that is in close contact with and covers the front half of the notch (35) of the core (28) is integrally formed. After the inner half of the rear half (37) fits into the rear half of the insulator mounting space (33) of the core (28) and excludes the inner peripheral surface of the pole (28b) of the core (28) A coil mounting portion (37a) covering the side portion is integrally formed. On the outer peripheral side of the rear half (37), a flat front protrusion (37b) that is in close contact with and covers the rear half of the notch (35) of the core (28) is integrally formed. . A board projection (37c) extending rearward is formed integrally with a portion on the radially outer side of the coil mounting portion (37a) of the rear half (37). A metal female screw member (38) having a female screw formed on the inner periphery is embedded inside the rear end of each substrate projection (37c). In the rear half (37), three first bus bars (39) and one second bus bar (40) are integrally formed by insert molding.

  Details of the first bus bar (39) are shown in FIG. 5, and details of the second bus bar (40) are shown in FIG.

  The first bus bar (39) is a UVW bus bar that connects one end of the three-phase coil (30) and the substrate (31). The second bus bar (40) is a neutral point bus bar that connects the other ends of the three-phase coil (30). The first bus bar (39) and the second bus bar (40) are made of a conductive metal such as copper oxide free and phosphor bronze.

  The first bus bar (39) is integrally formed with a coil connection end (39b) and an annular substrate connection end (39c) at both ends of a relatively short first bus bar body (39a) bent in an L shape. It is what. The first bus bar body (39a) is integrally formed with a rectangular plate-like heat radiating portion (39d). The first bus bar body (39a) is buried in the rear half (37). The coil connection end (39b) is exposed at the rear end face of the rear half (37) where there is no substrate projection (37d). The board connection end (39c) is exposed around the female screw member (38) at the rear end face of the board projection (37d). The heat dissipating part (39d) is exposed in close contact with the outer surface of the front projecting part (37b) of the rear half (37), and the front part of the heat dissipating part (39d) is forward from the front projecting part (37b). It protrudes.

  The second bus bar (40) has a coil connection end (40b) integrally formed at three locations of a relatively long second bus bar body (40a) bent along the outer periphery of the rear half (37). It is what. The second bus bar body (40a) is integrally formed with three rectangular plate-like heat radiation portions (40c). The second bus bar body (40a) is buried in the rear half (37). The coil connection end (40b) is exposed at the rear end surface of the rear half (37) where there is no substrate projection (37d). The heat dissipating part (40c) is exposed in close contact with the outer surface of the front protrusion (37b) of the rear half (37), and the front part of the heat dissipating part (40c) is forward from the front protrusion (37b). It protrudes.

  With both halves (36) (37) assembled in the core (28), the front part of the heat dissipating part (39d) (40c) of each bus bar (39) (40) is connected to the front half (36). It is in close contact with the outer surface of the rear protrusion (36b). Also, the coil (30) is wound around the coil mounting part (36a) (37a) of the insulator (29) covering the pole part (28b) of the core (28), and the coil connection end part of both bus bars (39) (40) One ends of the coils (30) corresponding to (39b) and (40b) are connected by fusing.

  The motor case (13) is integrated with the stator (27) by molding a synthetic resin such as PA66 (polyamide 66) on the outer peripheral side of the stator (27) using a mold. The stator (27) except for the inner peripheral surface of the pole portion (28b) of the core (28), the inner peripheral surfaces of the coil mounting portions (36a) (37a) of the insulator (29), and the rear end surface of the protrusion (37c). Is covered with a motor case (13). The coil connection end (39b) of the first bus bar (39) and the coil connection end (40b) of the second bus bar (40) are embedded in the motor case (13). In addition, the heat dissipating parts (39d) and (40c) of the bus bars (39) and (40) located outside the protruding parts (36b) and (37b) of the insulator (29) are also motors located radially outside the core (28). Covered by the case (13). The heat dissipating part (39d) (40c) of the bus bar (39) (40) located outside the notch part (35) of the core (28) is the core (28) where the notch part (35) is not formed. ) Is located radially inward from the cylindrical surface connecting the outer peripheral surfaces. A connector (42) having a plurality of pins (41) is integrally formed on the outer periphery of the motor case (13).

  The lid (14) is made of synthetic resin and is fixed to the rear end of the motor case (13) by an appropriate means such as heat welding.

  The substrate (31) of the controller (4) is fixed to the insulator (29) by a screw (43) screwed to the female screw member (38) of the protrusion (37c) of the insulator (29). Thus, the coil (30) is electrically connected to the substrate (31) via the substrate connection end (39c) of the first bus bar (39). The pin (41) of the connector (42) is also electrically connected to the substrate (31).

  In the electric pump unit described above, the heat generated in the coil (30) is transmitted to the heat radiating part (39d) (40c) through the bus bar (39) (40), and from the heat radiating part (39d) (40c) to the motor case ( Heat is dissipated outside through 13). Thereby, the coil (30) and the stator (27) are cooled, and the temperature rise is prevented. By preventing the temperature increase of the coil (30) and the stator (27), a decrease in motor characteristics is suppressed, and the temperature increase of the component (32) on the board (31) of the controller (4) is also prevented.

  Since the heat dissipating part (39d) (40c) of the bus bar (39) (40) is arranged in the cutout part (35) on the outer periphery of the core (28), the heat dissipating part (39d) (40c) The outer dimensions of the are not increased. In particular, the heat dissipating part (39d) (40c) of the bus bar (39) (40) is located radially inward from the cylindrical surface connecting the outer peripheral surface of the core (28) where the notch (35) is not formed. Therefore, the outer dimensions of the core (28) can be made the same as in the conventional case where the heat radiating portions (39d) and (40c) are not provided. The portion radially outside the caulking portion (34) of the core (28) does not contribute to the flow of magnetic flux density. For this reason, even if the notch (35) is formed in this portion, the motor characteristics are not affected. In addition, you may make it arrange | position the thermal radiation part of a bus-bar outside the insulator which covers at least one part of the outer peripheral surface of a cylindrical core, without forming a notch part in the outer periphery of a core.

  In the above example, the heat radiating part (39d) (40c) is formed integrally with the bus bar (39) (40), but the heat radiating part made separately from the bus bar (39) (40) is the bus bar (39) (40). 40) may be fixed. The greater the number of heat dissipating parts, the higher the heat dissipating effect. However, the heat radiating part may be provided only in one of the first bus bar (39) and the second bus bar (40). The heat radiating part (39d) may be provided on all of the first bus bars (39) or may be provided on a part thereof. Two or less heat dissipating parts (40c) may be provided in the second bus bar (40).

  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 motors other than the electric pump unit for motor vehicles.

(3) Electric motor
(13) Motor case
(27) Stator
(28) Core
(29) Insulator
(30) Stator coil
(35) Notch
(39) 1st bus bar
(39d) Heat sink
(40) Second bus bar
(40c) Heat sink

Claims (4)

A stator coil is wound around a synthetic resin insulator covering the stator core, and a bus bar connected to the stator coil is incorporated,
A stator in which a heat dissipating part provided on a bus bar is disposed outside an insulator that covers an outer peripheral surface of a stator core.   The stator according to claim 1, wherein the outer periphery of the annular stator core is cut out, and the heat dissipating part of the bus bar is arranged outside the insulator covering the outer peripheral surface of the cutout part.   The stator according to claim 1 or 2, wherein the insulator is integrally formed with the synthetic resin motor case, and the heat radiating portion of the bus bar is covered with a portion of the motor case located on the radially outer side of the stator core.   An electric motor comprising the stator according to claim 1.

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