JP2012044795A - Electric motor, and rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor of an electric motor, that has little possibility of causing deposition of foreign matters between a permanent magnet holding member and a permanent magnet.SOLUTION: In this rotor 13, a plurality of permanent magnets 23 are held by a permanent magnet holding member 31 made of a synthetic resin which is fixedly provided in the peripheral part of a cylindrical rotor body 30. The permanent magnet holding member 31 is composed of ring parts 37 closely adhering to both end faces 33a of the rotor body 30 in the axial direction thereof, and connecting parts 38 closely adhering to a peripheral surface 33 to connect both ring parts 37 in the circumferential direction of the rotor body 30, the permanent magnet 23 is fitted between two connecting parts 38 adjacent to each other, and both fringe parts of the permanent magnet 23 is held from the outside of the rotor body 30 by engagement holding parts 41, 42 projecting in the circumferential direction from both circumferential fringe parts of each connecting part 38, and the permanent magnet 23 is thereby held. The circumferential tip fringe 41a of the engagement holding part 41 on at least one side in the circumferential direction is inclined so that the projected amount of the tip fringe 41a becomes small as it goes to both ends in the axial direction.

Description

  The present invention relates to an electric motor and a rotor in an electric pump unit used as a hydraulic pump for supplying hydraulic pressure to a 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 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).

  As an electric motor in this type of electric pump unit, a DC brushless motor using a permanent magnet as a rotor is used. A DC brushless motor used for an electric pump unit is generally composed of a motor shaft connected to a pump, a motor rotor fixed to the motor shaft, and a motor stator disposed around the motor rotor. The motor stator includes a core having teeth (magnetic poles) provided at a plurality of locations in the circumferential direction, an insulator incorporated so as to cover a predetermined portion of the core, and a stator coil wound around the portion of the insulator covering the teeth. And. The rotor rotates with a slight gap between the stator teeth and the permanent magnets on the outer periphery of the rotor.

  In a conventional DC brushless motor, a ring-shaped or segment-shaped permanent magnet is fixed to the outer peripheral surface of a cylindrical rotor body with an adhesive. As described above, when the permanent magnet is fixed to the rotor body with an adhesive, the adhesive may be peeled off in an electric motor used in a severe environment.

  In order to prevent the permanent magnet from falling off due to the peeling of the adhesive, a segment-shaped permanent magnet is molded with a synthetic resin on the outer peripheral surface of the rotor main body, or a synthetic resin cage that is fixedly provided on the outer peripheral portion of the rotor main body. It has been proposed to hold a segment-shaped permanent magnet with such a permanent magnet holding member. (For example, refer to Patent Document 2).

JP 2008-215088 A JP 2010-004661 A

  On the other hand, the above-described conventional electric pump unit is fixed to the outside of the transmission with screws or the like and connected to the transmission by piping.

  For this reason, the unit housing is waterproofed by a seal, and a seal for waterproofing the electrical components of the electric motor and controller is also required inside the unit housing. Further, it is necessary to dissipate heat generated by a coil or the like constituting a motor stator of the pump driving electric motor, which causes a problem that the size of the electric pump unit is increased.

  In order to further improve the heat dissipation of the electric pump unit, the controller is separated from the electric pump unit, the controller is placed outside the transmission housing, and oil is put into the motor housing for the purpose of improving the heat dissipation of the electric motor by oil cooling. It is conceivable to introduce a structure that drives an electric motor in oil.

  Adopting such a structure, a brushless DC motor designed to hold a segment-shaped permanent magnet with a synthetic resin permanent magnet holding member fixed in the outer periphery of the rotor body is driven in oil. When doing so, foreign matter such as metal powder contained in the oil may accumulate between the permanent magnet holding portion of the permanent magnet holding member and the permanent magnet, which may lock the motor.

  An object of the present invention is to solve the above problems and provide an electric motor and a rotor that are less likely to deposit foreign matter between a permanent magnet holding member and a permanent magnet.

  A rotor according to the present invention is a permanent magnet holding member in a rotor of an electric motor in which a plurality of permanent magnets are held on a synthetic resin permanent magnet holding member fixedly provided on an outer peripheral portion of a cylindrical rotor body. Is formed of an annular portion that is in close contact with both axial end surfaces of the rotor body, and a connecting portion that is in close contact with the outer peripheral surface of the rotor body and connects both annular portions at a plurality of locations in the circumferential direction of the rotor body. A permanent magnet is fitted between the two connecting portions adjacent to each other, and the peripheral portion of the permanent magnet from the radially outer side of the rotor body is an engagement holding portion projecting in the circumferential direction from both circumferential edges of each connecting portion. By suppressing both edges in the direction, the permanent magnet is held, and in each connecting portion, the circumferential tip edge of the engagement holding portion on at least one side in the circumferential direction is the shaft. As you go to both ends It is characterized in that the amount of projection up to the tip edge is inclined so as to decrease.

  When the rotor is rotated only in one direction, only the front end edge of the engagement holding portion on the front side in the rotation direction needs to be inclined as described above.

  When the rotor is rotated in both directions, the leading edges of the engagement holding portions on both sides of each connecting portion are inclined as described above. If it does in this way, even if a rotor rotates in any direction, the front-end edge of the engagement holding part which becomes a rotation direction front side will incline as mentioned above. That is, the front end edge of the engagement holding portion on the front side in the rotation direction is inclined so as to be on the rear side in the rotation direction toward the both ends in the axial direction.

  When the rotor rotates with respect to the stator, the permanent magnets on the outer periphery of the rotor repeat the fact that they pass through the inside of the stator after approaching the teeth portion of the stator and leave. When the permanent magnet approaches the tooth portion, the tip edge of the engagement holding portion that is the front side in the rotation direction of the connecting portion is inclined as described above, so the axial center portion of the tip edge approaches the tooth portion first. As a result, the gap between the teeth portion becomes small, but at this time, the gap between the both ends in the axial direction of the tip edge and the teeth portion is large. For this reason, the oil existing between the permanent magnet and the tooth portion is pushed out toward the both end portions in the axial direction having a large gap, and flows to both end portions along the inclination. The foreign matter contained in the oil also flows to both ends in the axial direction together with the oil, and is difficult to be deposited between the tip edge and the permanent magnet.

  Even when the rotor is rotated only in one direction, the leading edges of the engagement holding portions on both sides of each connecting portion may be inclined as described above.

  If it does in this way, even if it integrates so that a rotor may rotate to which direction, the engagement holding part which becomes a rotation direction front side will incline as mentioned above.

  The rotor according to the present invention is also a permanent magnet in a rotor of an electric motor in which a plurality of permanent magnets are held on a synthetic resin permanent magnet holding member fixedly provided on an outer peripheral portion of a cylindrical rotor body. The holding member includes an annular portion that is in close contact with both axial end surfaces of the rotor body, and a connecting portion that is in close contact with the outer peripheral surface of the rotor body and connects both annular portions at a plurality of locations in the circumferential direction of the rotor body. A permanent magnet is fitted between two connecting portions adjacent in the circumferential direction, and the engagement holding portions projecting in the circumferential direction from both circumferential edges of each connecting portion are used to move the permanent magnet from the radially outer side of the rotor body. The circumferential edges are restrained so that permanent magnets are held, and connected in the axial direction to the circumferential central portion of the radially outward surface of each coupling portion. The first groove over the entire length of the part A second groove reaching the first groove from the surface of the permanent magnet is formed in the engagement holding portion on at least one side in the circumferential direction, and extends from the surface of the permanent magnet to the first groove. It is.

  When the rotor is rotated only in one direction, the second groove only needs to be formed only in the engagement holding portion on the front side in the rotation direction.

  When the rotor is rotated in both directions, second grooves are formed in the engagement holding portions on both sides of each connecting portion. If it does in this way, even if a rotor rotates in any direction, the 2nd groove | channel will be formed in the engagement holding | maintenance part which becomes a rotation direction front side.

  When the leading edge of the engagement holding portion, which is the front side in the rotation direction of the connecting portion, approaches the teeth portion of the stator due to the rotation of the rotor and the gap between the two becomes small, the oil between them becomes the second groove. Through the first groove and discharged from both ends of the first groove. Foreign matter contained in the oil is also discharged together with the oil and is not easily deposited between the tip edge and the permanent magnet.

  Even when the rotor is rotated only in one direction, second grooves may be formed in the engagement holding portions on both sides of each connecting portion.

  If it does in this way, even if it integrates so that a rotor may rotate to which direction, the 2nd groove | channel is formed in the engagement holding part which becomes a rotation direction front side.

  In the case where the second grooves are formed in the engagement holding portions on both sides of each connecting portion, it is preferably shifted so that the axial positions of the second grooves on both sides do not coincide.

  In this way, oil and foreign matter that have flowed from the second groove on the front side in the rotational direction to the first groove are surely discharged from both ends of the first groove.

  For example, rotation stoppers are formed at multiple locations in the circumferential direction of the outer periphery at both ends of the rotor body, and a plurality of rotation protrusions that fit into the rotation stoppers of the rotor body are integrally formed on the permanent magnet holding member. Has been.

  In this way, since the non-rotating convex portion of the permanent magnet holding member fits into the non-rotating concave portion of the rotor body, even if the outer peripheral surface of the rotor body is a cylindrical surface, the permanent magnet is rotated with respect to the rotor main body. The holding member does not slide in the circumferential direction, and the permanent magnet holding member is securely fixed. If the outer peripheral surface of the rotor body is a cylindrical surface, the processing is easy and can be manufactured at low cost.

  The anti-rotation recessed part formed in a rotor main body is a notch shape ranging from the outer peripheral surface end part of a rotor main body to an outer peripheral surface edge part, for example. In this case, the rotation prevention convex part of the permanent magnet holding member is formed on the mutually opposing surfaces of the two annular parts. The anti-rotation recess may be a bottomed hole formed in one of a plurality of locations on the end surface and the outer peripheral surface of the rotor main body or a plurality of locations on both. In any case, the detent protrusion of the permanent magnet holding member is provided at a position corresponding to the detent recess of the rotor body.

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

  According to the electric motor and the rotor of the present invention, as described above, there is little possibility that foreign matter will accumulate between the permanent magnet holding member and the permanent magnet, and therefore there is little possibility that the motor will be locked due to foreign matter accumulation.

FIG. 1 is a longitudinal sectional view of an electric pump unit showing a first embodiment of the present invention. FIG. 2 is an enlarged arrow view taken along line II-II in FIG. FIG. 3 is an enlarged sectional view taken along line III-III in FIG. FIG. 4 is a virtual exploded perspective view of the rotor of the electric motor. FIG. 5 is an enlarged perspective view showing the main part of the rotor. FIG. 6 is a perspective view of a main part of a rotor showing a second embodiment of the present invention.

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

  1 to 5 show a first embodiment.

  FIG. 1 is a longitudinal cross-sectional view showing portions of a pump (2) and an electric motor (3) for driving a pump of an idle stop electric pump unit (1) of an automobile transmission. In the following description, the left side of FIG. 1 is the front and the right side is the rear.

  The electric pump unit for transmission (1) of the present embodiment is used for auxiliary supply of hydraulic pressure that is reduced during idle stop in an automobile transmission, and is a vertical component that constitutes a transmission housing (4) of the automobile transmission. Is disposed in a recess (5) formed on the rear surface (outer surface) of the vertical wall (4a) having a bottomed circular hole with an open rear portion. The pump (2) and the motor (3) are integrated with the lid (6), thereby constituting the transmission electric pump unit (1). The motor (3) is disposed on the front surface of the lid (6), and the pump (2) is disposed in front of the motor (3). A pump (2) and a motor (3) are fitted in the recess (5), and a lid (6) seals the rear opening of the recess (5). 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 pump (2) includes a short cylindrical pump housing (7), and an outer gear (outer rotor) (10) is rotatably accommodated in a pump chamber (8) formed in the housing (7). An inner gear (inner rotor) (11) that meshes with the inner gear (11) is arranged inside (10).

  The motor (3) includes a horizontally disposed pump drive motor shaft (12), a motor rotor (13) fixed to a rear portion of the motor shaft (12), and a motor stator ( 14). In the following description, the axial direction, the radial direction, the circumferential direction, and the rotation direction refer to the rotor (13).

  The lid (6) has a disc shape, and is fixed to the rear surface of the vertical wall (4a) through an O-ring (15) by an appropriate means such as a bolt (not shown) around the recess (5). A short cylindrical portion (6a) concentric with the recess (5) is integrally formed at the center of the front surface (inner surface) of the lid (6), and a connector (16) is formed on the rear surface (outer surface) of the lid (6). ing.

  The stator (14) is an insulator (synthetic resin insulator) (18) incorporated in a core (17) made of laminated steel sheets, and a stator coil (19) is wound around the insulator (18). . Although not shown in detail, the core (17) is provided with a plurality of teeth (magnetic poles) (17a) extending radially inward, and the coil (19) is an insulator that covers the teeth (17a). It is wound around (18). The rear end surface of the insulator (18) is fixed to the front surface of the lid (6) by an appropriate means such as adhesion. A part of the stator (14) is in contact with the peripheral wall (5a) of the recess (5). Although not shown, the coil (19) is connected to the connector (16). The rear end surface of the pump housing (7) is fixed to the front end surface of the insulator (18) by appropriate means such as adhesion.

  The rear end portion of the motor shaft (12) is rotatably supported by a bearing device (20) provided in the small diameter short cylindrical portion (6a) of the lid (6). In this example, the bearing device (20) is composed of a ball bearing which is a single rolling bearing. The front part of the motor shaft (12) penetrates the part of the hole (21) formed in the rear wall (7a) of the pump housing (7) and enters the pump chamber (8), and its front end part is the pump It is connected to the inner gear (11) of (2). A bush (22) is interposed between the motor shaft (12) and the peripheral wall of the hole (21), and no seal is provided at this portion. The bush (22) is fitted in the hole (21), and slides between the inner peripheral surface of the bush (22) and the outer peripheral surface of the motor shaft (12) to constitute a slide bearing.

  The rotor (13) has a cylindrical shape extending radially outward from the rear portion of the motor shaft (12) and surrounding the motor shaft (12) inside the stator (14), and a permanent magnet (23) is disposed on the outer periphery thereof. Is provided.

  A gap is provided between the outer peripheral surface of the pump housing (7) and the peripheral wall (5a) of the recess (5), and the pump chamber (8) is provided below the peripheral wall (7b) of the pump housing (7). An oil suction hole (25) connected to the arc-shaped oil suction port (24) is provided. An oil discharge hole (27) connected to the arc-shaped oil discharge port (26) of the pump chamber (8) is formed at an appropriate location on the front wall (7c) of the pump housing (7), and an oil discharge pipe is formed in the discharge hole (27). (28) is connected. The discharge pipe (28) passes through the bottom wall (front wall) (4b) of the recess (5) of the transmission housing (4) and is not shown in the figure, but is connected to a required part of the transmission, Alternatively, it is connected to a required part of the transmission via another pipe.

  An oil suction hole (29) communicating with an oil pan (not shown) is formed in the lower part of the peripheral wall (5a) of the recess (5) of the housing vertical wall (4a), and through this hole (29), the recess (5) Oil (0) can enter inside. At least a part of the pump (2) and the motor (3) is immersed in the oil (0). In this example, the lower part of the stator (14) is immersed in oil (0).

  2 to 5 show details of the rotor (13). 2 is an enlarged arrow view taken along line II-II in FIG. 1, FIG. 3 is an enlarged sectional view taken along line III-III in FIG. 2, FIG. 4 is a virtual exploded perspective view of the rotor (13), FIG. FIG. 4 is an enlarged perspective view showing a main part of a rotor (13).

  In the rotor (13), a synthetic resin permanent magnet holding member (31) is fixedly provided on the outer periphery of a cylindrical rotor body (back yoke) (30), and the holding member (31) is equally divided in the circumferential direction. The segment-shaped permanent magnet (23) is held at a plurality of locations (eight locations in this example). The rotor (13) rotates in a fixed direction indicated by an arrow in FIGS.

  The rotor body (30) is, for example, a sintered body of magnetic metal, and is integrally formed on the outer peripheral end of the flange portion (32) fixed to the motor shaft (12) and the flange portion (32). It consists of a cylindrical part (33) extending forward so as to surround 12). The portion of the motor shaft (12) between the bearing device (20) and the bush (22) is fixed by press-fitting into a circular through hole (34) formed at the center of the flange portion (32). At least one key groove (35) is formed in the through hole (34). In this example, two key grooves (35) are formed at two symmetrical positions of the hole (35). The entire outer peripheral surface of the cylindrical portion (33) is a cylindrical surface, and the cross-sectional shape of the outer peripheral surface is circular. On the outer peripheral part of both ends of the cylindrical part (33), a rotation-preventing concave part (36) is formed at a plurality of places (eight places in this example) equally divided in the circumferential direction. In this example, the concave portion (36) is formed in the outermost peripheral portion of both end faces of the cylindrical portion (33), and has a notch shape extending from the outer peripheral portion of the cylindrical portion (33) to the end portion of the outer peripheral surface.

  The holding member (31) is integrated with the cylindrical portion (33) by molding a synthetic resin on the outer peripheral portion of the cylindrical portion (33) using a mold. The holding member (31) has an annular part (37) that is in close contact with the outer peripheral part of both end faces (33a) of the cylindrical part (33), and a plurality of places in the circumferential direction that are in close contact with the outer peripheral face (33b) of the cylindrical part (33). And a connecting portion (38) for connecting both annular portions (37). A plurality of anti-rotation convex portions (39) that fit into the concave portions (36) of the cylindrical portion (33) are integrally formed on the mutually opposing surfaces of both annular portions (37). The connecting portion (38) is formed at the same circumferential position as the convex portion (39) at a plurality of locations (eight locations in this example) that equally divide the annular portion (37) in the circumferential direction. The connecting portion (38) extends in the axial direction, connects both the annular portions (37), and holds the permanent magnet (23).

  A V-shaped groove (first groove) (40) extending over the entire axial length of the connecting portion (38) is formed at the center in the circumferential direction of the radially outward surface of each connecting portion (38). Each connecting portion (38) is integrally formed with two front and rear engagement holding portions (41) (42) projecting from the radially outer end to both sides in the circumferential direction. The leading edge (41a) of the first engagement holding part (41) on the front side in the rotation direction is inclined so that the amount of protrusion to the leading edge (41a) decreases toward both axial ends. As a result, the tip edge (41a) is inclined so as to be on the rear side in the rotational direction as it goes to both ends in the axial direction. In this example, it inclines linearly from the axial center to both axial ends. The tip edge (42a) of the second engagement holding portion (42) on the rear side in the rotation direction extends linearly in the axial direction so that the amount of protrusion to the tip edge (42a) is constant.

  The permanent magnet (23) is inserted axially between two circumferentially adjacent connecting portions (38), and both edges in the circumferential direction are restrained from the radially outer side by the engagement holding portions (41) (42). And the magnetic attraction force with the rotor body (30).

  Since the holding member (31) is formed integrally with the rotor body (30), the two are not separated, but in order to facilitate understanding of the configuration of both, in FIG. It is shown as a separate exploded perspective view.

  The anti-rotation recess formed in the cylindrical portion (33) of the rotor body (30) is not a notch-shaped recess (36) extending from the end surface of the cylindrical portion (33) to the outer peripheral surface as described above, but the cylindrical portion (33 ) May be a bottomed hole formed at one of a plurality of locations on the end surface and the outer peripheral surface, or at a plurality of locations of both. In that case, the non-rotating convex portion of the holding member (31) is provided at a position corresponding to the concave portion which is a bottomed hole. When the rotor body is a sintered body, it is difficult to process the hole, and thus the notch-shaped recess (36) as described above is preferable.

  The controller (not shown) of the motor (3) is disposed outside the transmission and is connected to the motor (3) via the connector (16) of the lid (6).

  While the vehicle 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) operates, the oil (0) in the recess (5) is sucked into the pump chamber (8) from the suction hole (25) and discharged from the discharge hole (27) to the discharge pipe (28). Then, it is supplied to a required part of the transmission through the discharge pipe (28).

  When the motor (3) is driven, the rotor (13) rotates with respect to the stator (14). When the rotor (13) rotates with respect to the stator (14), the permanent magnet (23) on the outer periphery of the rotor (13) approaches the teeth portion (17a) of the stator (14) and then passes through the inside to leave. Repeat that. When the permanent magnet (17a) approaches the teeth portion (17a), the tip edge (41a) of the first engagement holding portion (41) on the front side in the rotational direction of the coupling portion (38) is inclined as described above. Therefore, the central part in the axial direction of the tip edge (41a) approaches the tooth part (17a) first and the gap with the tooth part (17a) becomes smaller, but at this time, both ends of the tip edge (41a) in the axial direction The gap between the teeth part (17a) is large. For this reason, the oil between the permanent magnet (23) and the teeth portion (17a) is pushed out to both end portions in the axial direction with a large gap, and flows to both end portions along the inclination of the tip edge (41a). Accordingly, the foreign matter contained in the oil is unlikely to accumulate between the tip edge (41a) and the permanent magnet (23).

  In the above embodiment, the motor shaft (12) is passed through and fixed to the through hole (34) formed in the rotor body (30), so the rotor body (30) is the motor shaft (12). Separately, it can be composed of a sintered body. Then, when the permanent magnet holding member (31) is integrally formed on the outer peripheral portion of the rotor body (13), the key groove (35) of the through hole (34) can be used for phasing, the mold and the molding The process can be simplified. In addition, since only the key groove (35) is provided in the through hole (34) formed in the rotor body (30), the structure of the mold when the rotor body (30) is formed of a sintered body is simplified. The

  In the above-described embodiment, the tip edge (41a) of the first engagement holding portion (41) on the front side in the rotation direction is formed in an inclined shape by a combination of two straight lines, but a combination of three or more straight lines, It may be formed in an inclined shape by a combination of one or a plurality of curves, or a combination of a plurality of straight lines and curves.

  Even when the rotor (13) rotates in only one direction as described above, the leading edge (42a) of the second engagement holding portion (42) on the rear side in the rotation direction of each connecting portion (38) You may make it incline similarly to the front-end edge (41a) of a 1st engagement holding part (41).

  In this way, regardless of the direction in which the rotor (13) is rotated, the engagement holding portions (41) (42) on the front side in the rotation direction are inclined as described above. Become.

  Depending on the application of the electric motor (3), the rotor (13) may be rotated in both directions. In such a case, the tip edges (41a) and (42a) of the engagement holding portions (41) and (42) on both sides of each connecting portion (38) are inclined as described above. In this way, the front edges (41a) and (42a) of the engagement holding portions (41) and (42) that are on the front side in the rotation direction are inclined as described above, regardless of which direction the rotor (13) rotates. Will be.

  FIG. 6 is a drawing corresponding to FIG. 5 showing the second embodiment. In FIG. 6, the same parts as those in FIG.

  In this case, in each coupling portion (38) of the permanent magnet holding member (31), the leading edges (41a) and (42a) of both engagement holding portions (41) and (42) are both linearly extended in the axial direction. And the 2nd groove | channel (43) which reaches the 1st groove | channel (40) from the surface of the hold | maintained permanent magnet (23) is formed in the 1st engagement holding | maintenance part (41) which becomes a rotation direction front side. . In this example, a second groove (43) is formed at one location in the axial center of the first engagement holding portion (41).

  In this case, when the motor (3) is driven and the rotor (13) rotates with respect to the stator (14), the front edge (41a) of the first engagement holding portion (41) of the connecting portion (38). When the gap approaches the teeth (41a) of the stator (14) and the gap between the two becomes small, the oil between the two passes through the second groove (43) to the first groove (40). The flow is discharged from both ends of the first groove (40). For this reason, the foreign substance contained in oil is hard to accumulate between a front-end edge (41a) and a permanent magnet (23).

  The number and position of the second groove can be arbitrarily changed.

  Even when the rotor (13) is rotated only in one direction as described above, the second groove (43) is formed in the engagement holding portions (41) (42) on both sides of each connecting portion (38). It may be formed.

  In this way, the second groove (43) is formed in the engagement holding portions (41) and (42) that are on the front side in the rotation direction, regardless of which direction the rotor (13) rotates. Will be.

  When the rotor (13) is rotated in both directions, the second groove (43) is formed in the engagement holding portions (41) and (42) on both sides of each connecting portion (38). In this way, the second groove (43) is formed in the engagement holding part (41) (42) which is the front side in the rotation direction regardless of which direction the rotor (13) rotates. Become.

  When the second groove (43) is formed in the engagement holding part (41) (42) on both sides of each connecting part (38), preferably the axial position of the second groove (43) on both sides is It is shifted.

  In this way, the oil and foreign matter flowing from the second groove (43) on the front side in the rotational direction to the first groove (40) are surely discharged from both ends of the first groove (40).

  In the transmission electric pump unit (1), the opening of the recess (5) into which the pump (2) and the electric motor (3) for driving the pump are formed in the transmission housing (4) and oil (0) is introduced. Is integrated with the lid (6) for sealing the inside of the housing and accommodated in the recess (5). For this reason, the unit housing of the conventional electric pump unit is unnecessary, and therefore the waterproofing of the unit housing is also unnecessary. Since the controller of the electric motor (3) is not provided in the transmission housing (4), its waterproofing is not necessary. In addition, a seal between the pump (2) and the electric motor (3) is not necessary. Therefore, it is possible to make the electric pump portion compact and reduce the weight and cost. Since the pump (3) operates while the vehicle is stopped, the height of the oil surface (0a) can be managed only by managing the amount of hydraulic oil (0).

  In the motor rotor (13), it may be possible to fix the permanent magnet (23) to the rotor body (30) with an adhesive. However, if the adhesive is used in an oily environment, the permanent magnet (23) may be peeled off. . In the above embodiment, the motor rotor (13) has a plurality of permanent magnets (23) on the permanent magnet holding member (31) made of synthetic resin fixedly provided on the outer periphery of the cylindrical rotor body (30). Therefore, it is not necessary to fix the permanent magnet (23) to the rotor body (30) with an adhesive, and there is no possibility of peeling.

  Furthermore, since the non-rotating convex portion (39) of the permanent magnet holding member (31) is fitted in the non-rotating concave portion (36) of the rotor body (30), the entire outer peripheral surface of the rotor main body (30) is a cylindrical surface. Even if the cross-sectional shape of the outer peripheral surface is circular, the permanent magnet holding member (31) does not slip in the circumferential direction with respect to the rotor body (30) by rotation, and the permanent magnet holding member (31) is fixed. Is certain. And since the outer peripheral surface of a rotor main body (30) is a cylindrical surface, the process is easy and can be manufactured cheaply.

  However, the configurations of the rotor body (30) and the holding member (31) are not limited to those of the above-described embodiment, and can be changed as appropriate.

  Since part of the motor stator (14) is in contact with the transmission housing (4) having a large heat capacity, the heat generated in the stator (14) is efficiently radiated. Furthermore, the heat generated in the stator (14) is also radiated from the portion immersed in the oil (0). For this reason, it is not necessary to increase the size of the electric pump portion for heat dissipation, and the electric pump portion can be made compact and the weight and cost can be reduced.

  In the above example, oil (0) is introduced into the lower part of the recess (5), and the lower part of the stator (14) of the motor (3) is immersed in the oil (0). ) Oil may be introduced to the whole, and the entire motor (3) may be immersed in the oil.

  The overall configuration of the electric pump unit (1) 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 rotor
(23) Permanent magnet
(30) Rotor body
(31) Permanent magnet holding member
(33) Rotor body cylindrical part
(33a) End face
(33b) Outer surface
(37) Annulus
(38) Connecting part
(40) First choice
(41) Front engagement holder
(41a) Tip edge
(42) Rear engagement holder
(43) Second choice

Claims (3)

In the rotor of the electric motor in which a plurality of permanent magnets are held on a synthetic resin permanent magnet holding member fixedly provided on the outer peripheral portion of the cylindrical rotor body,
The permanent magnet holding member is composed of an annular portion that is in close contact with both axial end surfaces of the rotor body, and a connecting portion that is in close contact with the outer peripheral surface of the rotor body and connects both annular portions at a plurality of locations in the circumferential direction of the rotor body. A permanent magnet is fitted between the two connecting portions adjacent in the circumferential direction, and the engagement holding portions projecting in the circumferential direction from both circumferential edges of each connecting portion are permanent from the radially outer side of the rotor body. The permanent magnet is held by the fact that both circumferential edges of the magnet are suppressed,
In each of the connecting portions, the circumferential tip edge of the engagement holding portion on at least one side in the circumferential direction is inclined so that the amount of protrusion to the tip edge becomes smaller toward the both ends in the axial direction. Rotor characterized by In the rotor of the electric motor in which a plurality of permanent magnets are held on a synthetic resin permanent magnet holding member fixedly provided on the outer peripheral portion of the cylindrical rotor body,
The permanent magnet holding member is composed of an annular portion that is in close contact with both axial end surfaces of the rotor body, and a connecting portion that is in close contact with the outer peripheral surface of the rotor body and connects both annular portions at a plurality of locations in the circumferential direction of the rotor body. A permanent magnet is fitted between the two connecting portions adjacent in the circumferential direction, and the engagement holding portions projecting in the circumferential direction from both circumferential edges of each connecting portion are permanent from the radially outer side of the rotor body. Permanent magnets are held by suppressing both circumferential edges of the magnet,
A first groove extending in the axial direction and extending over the entire length of the connecting portion is formed at the circumferentially central portion of the radially outward surface of each connecting portion, and is engaged and held on at least one side in the circumferential direction. And a second groove extending in the circumferential direction and reaching the first groove from the surface of the permanent magnet.   An electric motor comprising the rotor according to claim 1.

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