JP2017123761A - In-wheel motor driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit the output drop and the efficiency deterioration of an electric motor base on insufficient cooling of a stator.SOLUTION: An in-wheel motor driving device includes: a driving part formed by an electric motor; a speed reduction part which reduces a speed of rotation of the driving part to output the rotation; a bearing part formed by a wheel bearing; a casing which houses the driving part; and a lubrication mechanism which supplies a lubrication oil to the driving part to cool the electric motor. The electric motor include a stator 23 fixed to the casing and including a core 75 around which a coil 76 is wound. The lubrication mechanism includes: an oil passage disposed at a core attachment portion of the casing; an oil hole provided at the oil passage and opening at a position above the coil 76; and a distribution plate 78 which is disposed between the oil hole and the coil 76 and receives the lubrication oil flowing down from the oil hole 77. An oil guide piece 82 is provided at a flow-down port 81 provided at the distribution plate 78 so as to extend downward to the coil 76.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an in-wheel motor drive device in which, for example, an output shaft of an electric motor and a wheel bearing are connected via a reduction gear.

  A conventional in-wheel motor drive device has a structure disclosed in Patent Document 1, for example. The in-wheel motor drive device disclosed in Patent Document 1 includes an electric motor that generates a driving force, a parallel shaft gear reducer that decelerates and outputs the rotation of the electric motor, and outputs from the parallel shaft gear reducer. It consists of a wheel hub that transmits to.

  This in-wheel motor drive device is provided with an intermediate plate between the electric motor and the parallel shaft gear reducer, a motor housing for accommodating the electric motor is provided on the inboard side of the intermediate plate, and an outboard of the intermediate plate The structure which provided the gear housing which accommodates a parallel shaft gear reducer in the side is comprised.

  The electric motor includes a stator fixed to a motor housing and a rotor shaft that is rotatably supported inside the stator. A parallel shaft gear reducer includes a motor input gear coaxially connected to a rotor shaft of an electric motor, a first counter gear rotatably supported by a gear housing and meshed with the motor input gear, a first counter gear, The second counter gear is supported coaxially, and the output gear is provided on the axle of the wheel hub and meshes with the second counter gear.

  In this in-wheel motor drive device, it is necessary to supply lubricating oil to the electric motor and the parallel shaft gear reducer for the purpose of cooling the electric motor and lubricating the parallel shaft gear reducer. As a lubrication structure for the electric motor and the parallel shaft gear reducer, a rotary pump is built in, and the lubricating oil discharged from the rotary pump is supplied to the electric motor and the parallel shaft gear reducer with a shaft center oil supply structure to the rotary pump. A circulating structure for reflux is possible.

JP 2014-46742 A

  By the way, the in-wheel motor driving device disclosed in Patent Document 1 requires an electric motor having a high speed rotation and a high torque while being small in size. Here, the electric motor generally includes a stator in which a coil is wound around a core made of a magnetic material. When this electric motor is rotated at high speed, the heat generation of the coil due to copper loss becomes significant.

  Therefore, in this in-wheel motor drive device, it is important to cool the coil of the stator of the electric motor. In this electric motor lubrication structure, the stator and rotor shaft of the electric motor can be cooled by the axial center oil supply structure.

  In this shaft center oil supply structure, the rotor shaft is cooled by pumping the lubricating oil from the shaft center oil passage formed in the rotor shaft to the outer periphery of the rotor shaft through the oil passage inside the rotor shaft. Furthermore, the stator is cooled by ejecting lubricating oil from the outer periphery of the rotor shaft toward the stator.

  However, it is difficult to say that the cooling of the stator coil is sufficient in the axial center oil supply structure in which lubricating oil is jetted from the outer periphery of the rotor shaft toward the stator. As a result, the heat generated by the stator coil may reduce the magnetic force of the core constituting the electric motor, leading to a reduction in the output and efficiency of the electric motor. .

  Therefore, the present invention has been proposed in view of the above-described problems, and an object of the present invention is to provide an in-wheel motor drive device that can suppress a decrease in output and a decrease in efficiency of an electric motor due to insufficient cooling of the stator. There is.

  An in-wheel motor drive device according to the present invention accommodates a drive unit configured with an electric motor, a deceleration unit that decelerates and outputs rotation of the drive unit, a bearing unit configured with a wheel bearing, and a drive unit. And a lubrication mechanism for cooling the electric motor by supplying lubricating oil to the drive unit.

  As technical means for achieving the above-described object, the electric motor of the present invention includes a stator fixed to a casing and having a coil wound around a core. Further, the lubrication mechanism of the present invention includes an oil passage disposed in the core mounting portion of the casing, an oil hole provided in the oil passage and opened at a position above the coil, and disposed between the oil hole and the coil. And a distribution plate that receives the lubricating oil flowing down from the oil hole, and a structure in which an oil guide piece extending downward toward the coil is provided at a flow-down port provided in the distribution plate.

  In the present invention, the lubrication mechanism of the drive unit employs a structure in which the oil guide piece is extended to the flow outlet of the distribution plate, so that the lubricant flowing down from the flow outlet of the distribution plate is fed to the stator coil by the oil guide piece. Can be directed towards. Therefore, the lubricating oil can be reliably supplied to the stator coil, so that the stator coil can be efficiently cooled.

  The stator according to the present invention preferably includes a plurality of coils arranged along the outer periphery of the annular core, and the distribution plate preferably has a circular arc shape having a plurality of flow-down openings arranged corresponding to the coils. If such a structure is adopted, lubricating oil can be efficiently supplied to a plurality of coils constituting the stator.

  The distribution plate in the present invention preferably has a structure having a wall portion standing at the end of the receiving portion that receives the lubricating oil flowing down from the oil hole. By adopting such a structure, it is possible to prevent the lubricating oil from leaking from the end of the receiving portion and flowing down to a portion other than the stator coil.

  According to the present invention, the structure in which the oil guide piece is extended to the flow outlet of the distribution plate is adopted as the lubrication mechanism of the drive unit, so that the lubricating oil flowing down from the flow outlet of the distribution plate is fed to the stator by the oil guide piece. Can be guided towards the coil. Therefore, the lubricating oil can be reliably supplied to the stator coil, so that the stator coil can be efficiently cooled. As a result, it is possible to suppress an output decrease and efficiency deterioration of the electric motor.

In embodiment of this invention, it is sectional drawing which shows the whole structure of an in-wheel motor drive device. It is the schematic which looked at only the gearwheel which comprises the parallel shaft gear reducer of FIG. 1 from the outboard side. It is sectional drawing which follows the PP line | wire of FIG. It is an expanded sectional view which shows the rotor of the motor rotating shaft and electric motor of FIG. It is an expansion perspective view which shows the distribution board of FIG. It is a side view which shows the distribution plate of FIG. 5, and the coil of a stator. It is a perspective view which shows the modification of the distribution plate of FIG. It is a top view which shows schematic structure of the electric vehicle carrying an in-wheel motor drive device. FIG. 9 is a rear sectional view showing the electric vehicle of FIG. 8.

  An embodiment of an in-wheel motor drive device according to the present invention will be described in detail with reference to the drawings. FIG. 8 is a schematic plan view of the electric vehicle 11 on which the in-wheel motor drive device 21 is mounted, and FIG. 9 is a schematic cross-sectional view of the electric vehicle 11 as viewed from the rear.

  As shown in FIG. 8, the electric vehicle 11 includes a chassis 12, a front wheel 13 as a steering wheel, a rear wheel 14 as a drive wheel, and an in-wheel motor drive device 21 that transmits driving force to the rear wheel 14. Equip. As shown in FIG. 9, the rear wheel 14 is accommodated in a wheel housing 15 of the chassis 12, and is fixed to the lower portion of the chassis 12 via an independent suspension type suspension device (suspension) 16.

  In the electric vehicle 11, the in-wheel motor drive device 21 that drives the left and right rear wheels 14 is provided inside the wheel housing 15, thereby eliminating the need to provide a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 12. Therefore, there is an advantage that a wide cabin space can be secured and the rotation of the left and right rear wheels 14 can be controlled.

  In order to improve the running stability and NVH characteristics of the electric vehicle 11, it is necessary to suppress the unsprung weight, and further, the in-wheel motor drive device 21 is required to be downsized in order to secure a large cabin space.

  The in-wheel motor drive device 21 of the embodiment shown in FIG. 1 has the following structure. Thereby, the compact in-wheel motor drive device 21 is implement | achieved and the electric vehicle 11 excellent in driving | running | working stability and NVH characteristic can be obtained by restraining unsprung weight.

  Before describing the characteristic configuration of this embodiment, the overall configuration of the in-wheel motor drive device 21 will be described. In the following description, in a state where the in-wheel motor drive device 21 is mounted on the vehicle, the side closer to the outside of the vehicle is referred to as the outboard side (left side in FIG. 1), and the side closer to the center is referred to as the inboard side (see FIG. 1 on the right).

  As shown in FIG. 1, the in-wheel motor drive device 21 includes a drive unit A that generates a driving force, a deceleration unit B that decelerates and outputs the rotation of the drive unit A, and an output from the deceleration unit B as driving wheels. As a rear wheel 14 (see FIGS. 8 and 9). The drive part A and the speed reduction part B are accommodated in the casing 22 and attached to the wheel housing 15 (see FIG. 9) of the electric vehicle 11.

  The drive unit A is a stator 23 fixed to the casing 22, a rotor 24 disposed so as to face the inner side in the radial direction of the stator 23 with a gap, and a rotor 24 disposed on the inner side in the radial direction of the rotor 24 so as to rotate integrally with the rotor 24. A radial gap type electric motor 26 having a motor rotating shaft 25 is provided.

  The motor rotating shaft 25 can rotate at a high speed of about 10,000 to 1000 rotations per minute. The stator 23 is configured by winding a coil 76 around a core 75 made of a magnetic material. The rotor 24 has a permanent magnet or a magnetic material disposed therein.

  The motor rotating shaft 25 holds the rotor 24 by a holder portion 27 that extends integrally outward in the radial direction. The holder portion 27 has a configuration in which a concave groove into which the rotor 24 is fitted and fixed is formed in an annular shape. The motor rotating shaft 25 is rotatable with respect to the casing 22 by one end in the axial direction (right side in FIG. 1) on the rolling bearing 28 and the other end in the axial direction (left side in FIG. 1) by the rolling bearing 29. It is supported by.

  The reduction part B is composed of a parallel shaft gear reducer 39 including a first gear 30 as an input gear, second and third gears 31 and 32 as intermediate gears, and a fourth gear 33 as an output gear. ing. The speed reduction part B may be a speed reducer other than the parallel shaft gear speed reducer 39, for example, a planetary gear speed reducer or a cycloid speed reducer.

  In the parallel shaft gear reducer 39, the first gear 30 and the second gear 31 mesh with each other, and the third gear 32 and the fourth gear 33 mesh with each other, thereby reducing the rotational motion of the motor rotating shaft 25 in two stages. To do. In the parallel shaft gear reducer 39, the reduction ratio of the first stage consisting of the first gear 30 and the second gear 31 is about 2 to 4, and the reduction ratio of the second stage consisting of the third gear 32 and the fourth gear 33 is It is preferable to set it as about 3-5.

  The first gear 30 is coaxially attached and fixed to the motor rotating shaft 25 by connecting the shaft portion 34 extending to the inboard side to the motor rotating shaft 25 by spline fitting. The second gear 31 is attached and fixed to the intermediate shaft 35. The third gear 32 is formed integrally with the intermediate shaft 35. The fourth gear 33 is coaxially attached and fixed to the reduction gear output shaft 37 by connecting the shaft portion 36 to the inboard side shaft portion 38 of the reduction gear output shaft 37 by spline fitting.

  The shaft portion 34 of the first gear 30 is rotatably supported with respect to the casing 22 by a rolling bearing 40. The intermediate shaft 35 to which the second gear 31 is attached and fixed and the third gear 32 is integrally formed is rotatably supported by the casing 22 by rolling bearings 41 and 42. The shaft portion 36 of the fourth gear 33 to which the reduction gear output shaft 37 is attached and fixed is rotatably supported with respect to the casing 22 by rolling bearings 43 and 44. Outboard side shaft portion 45 of reduction gear output shaft 37 is connected to hub wheel 47 of bearing portion C by spline fitting, and transmits the output of reduction portion B to rear wheel 14 (see FIGS. 8 and 9).

  The 1st gearwheel 30-the 4th gearwheel 33, and the rotating shaft of each gearwheel are demonstrated based on FIG. FIG. 2 is a schematic view of only the first gear 30 to the fourth gear 33 constituting the parallel shaft gear reducer 39 of FIG. 1 as viewed from the outboard side.

  The first gear 30 is attached and fixed to the motor rotation shaft 25 (see FIG. 1), and rotates about its axis C1. The second gear 31 is attached and fixed to the intermediate shaft 35 (see FIG. 1), and the third gear 32 is formed integrally with the intermediate shaft 35 and rotates about its axis C2. The fourth gear 33 is fixedly attached to the speed reducer output shaft 37 (see FIG. 1), and rotates around its axis C3. In addition, since the motor rotating shaft 25 and the reduction gear output shaft 37 are arrange | positioned coaxially, each axial center C1 and axial center C3 correspond.

  In this embodiment, the shaft centers C1, C2, and C3 of the motor rotation shaft 25, the intermediate shaft 35, and the reduction gear output shaft 37 are arranged on a straight line EE, and the reduction portion B is reduced in the radial direction. Yes. However, the arrangement of the shaft centers C1, C2, and C3 is not limited to the arrangement as in this embodiment, and is appropriately shifted in consideration of the space of the casing 22 while maintaining the meshing of the gears 30 to 33. May be.

  Here, helical gears are used for the first gear 30 to the fourth gear 33. Helical gears are effective in that the number of teeth engaged simultaneously increases and the tooth contact is dispersed, so that the sound is quiet and torque fluctuation is small. In consideration of the meshing ratio of gears and the limit number of rotations, the number of modules is preferably about 1 to 3. Thus, by using a helical gear for the parallel shaft gear reducer 39, it is possible to realize the in-wheel motor drive device 21 that is easy to manufacture and can be reduced in cost, and that is quiet and efficient in terms of performance. it can.

  Since the in-wheel motor drive device 21 is housed inside the wheel housing 15 (see FIG. 9) and becomes an unsprung load, a reduction in size and weight is essential. For example, the reduction ratio at the first stage of the first gear 30 and the second gear 31 is 1 / 2.5, and the reduction ratio at the second stage of the third gear 32 and the fourth gear 33 is 1 / 4.5. In this case, the reduction ratio of the parallel shaft gear reducer 39 is about 1/11. Thus, when the parallel shaft gear reducer 39 having a large reduction ratio is used, the electric motor 26 can be reduced in size by combining with the high-speed electric motor 26 of about ten thousand rotations per minute. The in-wheel motor drive device 21 with a high reduction ratio can be realized.

  As shown in FIG. 1, the bearing portion C includes a wheel bearing 46 having the following structure. The wheel bearing 46 is disposed on the outer side of the hub wheel 47 and the inner ring 48, the hub wheel 47 connected to the reduction gear output shaft 37 so as to transmit torque, the inner ring 48 fitted to the outer periphery of the hub wheel 47. This is a double-row angular ball bearing including an outer ring 49, a plurality of balls 50 disposed between the hub ring 47 and the inner ring 48 and the outer ring 49, and a cage 51 that holds the plurality of balls 50. Seal members 52 are provided at both ends in the axial direction of the wheel bearing 46 to prevent intrusion of muddy water and the like and leakage of grease.

  The wheel bearing 46 is fastened and fixed to the parallel shaft gear reducer 39 by screwing a nut 53 into a male thread portion formed at an end of the outboard side shaft portion 45 of the reducer output shaft 37. An outer ring 49 of the wheel bearing 46 is fixedly attached to the casing 22. The inner ring 48 of the wheel bearing 46 is prevented from coming off by coming into contact with the flange portion 54 of the reduction gear output shaft 37. The rear wheel 14 (see FIGS. 8 and 9) is connected to the hub wheel 47 of the wheel bearing 46 by a hub bolt 55.

  The overall operation principle of the in-wheel motor drive device 21 having the above configuration will be described.

  As shown in FIG. 1, in the drive unit A, the rotor 24 rotates by receiving an electromagnetic force generated by supplying an alternating current to the stator 23. In the speed reduction part B, the rotation of the motor rotation shaft 25 is decelerated by the first gear 30 to the fourth gear 33 of the parallel shaft gear speed reducer 39 and is transmitted to the bearing part C via the speed reducer output shaft 37.

  At this time, the rotation of the motor rotating shaft 25 is decelerated by the parallel shaft gear reducer 39 and transmitted to the reducer output shaft 37. Therefore, even when the low torque, high speed rotating electric motor 26 is employed, the rear wheel 14 It is possible to transmit the torque required for (see FIGS. 8 and 9).

  In the above embodiment, the radial gap type electric motor 26 is exemplified as the driving unit A, but a motor having an arbitrary configuration is applicable. For example, an axial gap type electric motor including a stator fixed to a casing and a rotor arranged so as to face the inner side in the axial direction of the stator with a gap may be used.

  The overall configuration of the in-wheel motor drive device 21 in this embodiment is as described above, and the characteristic configuration will be described in detail below.

  The in-wheel motor drive device 21 supplies a lubricating oil for cooling the electric motor 26 of the driving unit A and a lubricating mechanism for supplying the lubricating oil for lubricating the parallel shaft gear reducer 39 of the reduction unit B. It has. As shown in FIG. 1, the lubrication mechanism includes a rotary pump 56, oil passages 57 and 58 provided in the casing 22, oil passages 59 to 63 provided in the motor rotation shaft 25, and the first gear 30. And the oil path 64,65 arrange | positioned at the axial part 34 is made into the main structure.

  The rotary pump 56 includes a pump drive shaft 66 that is coaxially connected to the inboard side end portion of the intermediate shaft 35, and is incorporated in the casing 22 by a presser plate 67. The pump drive shaft 66 is rotatably supported by the rolling bearing 41 with respect to the casing 22. A discharge port 68 and a suction port 69 of the rotary pump 56 are provided in the casing 22. In addition, an oil drain hole 71 (see FIG. 3) through which lubricating oil flows from the drive unit A to the speed reduction unit B is disposed in the partition wall 70 of the casing 22 that partitions the drive unit A and the speed reduction unit B. .

  As shown in FIG. 1, the oil passage 57 extending from the discharge port 68 of the rotary pump 56 circulates inside the casing 22 and communicates with the oil passage 59 at the inboard side end of the motor rotation shaft 25. The oil passage 59 communicates with a radial oil passage 60 extending toward the rotor 24 on the lubricating oil inflow side of the motor rotating shaft 25. The radial oil passage 60 communicates with an axial oil passage 61 extending in the axial direction while contacting the inner periphery of the rotor 24 at the end thereof. The axial oil passage 61 communicates with a radial oil passage 62 extending toward the axial center at the end thereof. The radial oil passage 62 communicates with the oil passage 63 on the lubricating oil outflow side of the motor rotating shaft 25 (see FIG. 4). The oil passage 63 communicates with the oil passage 64 of the shaft portion 34 of the first gear 30 at the outboard side end portion of the motor rotation shaft 25.

  An oil passage 64 extending along the axial direction inside the shaft portion 34 of the first gear 30 communicates with an oil passage 65 extending along the radial direction inside the first gear 30. The oil passage 64 of the shaft portion 34 of the first gear 30 opens at the outboard side end of the first gear 30. The oil passage 65 inside the first gear 30 opens at the tooth surface of the first gear 30.

  One end of the oil passage 58 for returning the lubricating oil to the rotary pump 56 communicates with the suction port 69 of the rotary pump 56, and the other end opens to the speed reduction part B side below the partition wall 70 of the casing 22. The rotary pump 56 for forcibly circulating the lubricating oil is provided between an oil passage 57 that communicates with the discharge port 68 and an oil passage 58 that communicates with the suction port 69.

  As shown in FIGS. 1 and 3, the rotary pump 56 includes an inner rotor 72 attached to an inboard side end of the pump drive shaft 66, an outer rotor 73 rotatably supported by the casing 22, a pump chamber 74, and the like. The cycloid pump includes a discharge port 68 communicating with the oil passage 57 and a suction port 69 communicating with the oil passage 58. Since the rotary pump 56 is driven by the rotation of the intermediate shaft 35, a separate drive mechanism is not required, so that the number of parts can be reduced.

  The inner rotor 72 rotates in synchronization with the rotation of the intermediate shaft 35 by being driven by decelerating the rotation of the motor rotation shaft 25 in the first stage composed of the first gear 30 and the second gear 31. On the other hand, the outer rotor 73 is driven to rotate as the inner rotor 72 rotates. By disposing the rotary pump 56 in the casing 22, it is possible to prevent the in-wheel motor drive device 21 from becoming large.

  The inner rotor 72 rotates about the rotation center C4, and the outer rotor 73 rotates about the rotation center C5. Since the inner rotor 72 and the outer rotor 73 rotate about different rotation centers C4 and C5, the volume of the pump chamber 74 changes continuously. As a result, the lubricating oil flowing from the suction port 69 is pumped from the discharge port 68 to the oil passage 57. When the number of teeth of the inner rotor 72 is n, the number of teeth of the outer rotor 73 is (n + 1). In this embodiment, n = 7.

  The flow of the lubricating oil by the lubricating mechanism will be described below. In FIG. 1, the white arrow attached to the inside of the oil passage of the in-hole motor drive device 21 indicates the flow of the lubricating oil. Although not shown, lubricating oil is stored in the lower part of the casing 22 in the drive unit A and the speed reduction unit B.

  In the drive unit A, the rotor 24 of the electric motor 26 is cooled as follows.

  The lubricating oil pumped from the discharge port 68 of the rotary pump 56 reaches the oil path 59 of the motor rotating shaft 25 via the oil path 57. In the motor rotating shaft 25, the lubricating oil reaches the axial oil passage 61 from the radial oil passage 60 by the centrifugal force and pump pressure accompanying the rotation, and the rotor 24 of the electric motor 26 is driven by the lubricating oil flowing through the axial oil passage 61. Cool down. The lubricating oil that has cooled the rotor 24 reaches the oil passage 63 through the radial oil passage 62 and travels toward the oil passage 64 of the shaft portion 34 of the first gear 30.

  In cooling the rotor 24 of the electric motor 26, the lubricating mechanism is composed of the radial oil passages 60 and 62 on the lubricating oil inflow side and the lubricating oil outflow side and the axial oil passage 61 in contact with the inner periphery of the rotor 24 of the electric motor 26. By configuring, the rotor 24 of the electric motor 26 can be cooled with the lubricating oil flowing through the axial oil passage 61.

  In this lubrication mechanism, a structure that does not eject the lubricating oil from the outer periphery of the rotor 24 is employed, unlike a conventional axial center oil supply structure. From this, it is possible to suppress a decrease in output and a deterioration in efficiency of the electric motor 26 based on the stirring resistance of the lubricating oil.

  In the drive unit A, the stator 23 of the electric motor 26 is cooled as follows.

  The lubrication mechanism for cooling the stator 23 has the following structure. As shown in FIG. 1, in an oil passage 57 disposed in the upper portion of the casing 22, an oil hole 77 that opens at a position above the coil 76 of the stator 23 is provided in a portion where the core 75 of the stator 23 is attached. ing. Between the oil hole 77 and the coil 76, a bowl-shaped distribution plate 78 that receives the lubricating oil flowing down from the oil hole 77 is disposed. In this embodiment, the distribution plate 78 is attached to the side surface of the core 75, but it is also possible to attach it to other fixed parts such as the casing 22.

  As shown in FIG. 5, the distribution plate 78 has an L-shaped cross section including a vertically arranged fixing portion 79 attached to the side surface of the core 75 and a horizontally arranged receiving portion 80 extending laterally from the fixing portion 79. Make. Further, as shown in FIG. 6, the receiving portion 80 of the distribution plate 78 has a plurality of coils 76 arranged along the circumferential direction of the annular core 75, and thus an arc along the arrangement direction of the coils 76. Has a shape.

  The receiving portion 80 of the distribution plate 78 is provided with a plurality of (three in the drawing) flow-down ports 81 corresponding to the coils 76 positioned on the upper portion of the core 75. A tongue-shaped oil guide piece 82 extending downward toward the coil 76 is provided at both ends of the three flow-down ports 81 and the receiving portion 80. That is, five oil guiding pieces 82 are arranged above each coil 76 with respect to the five coils 76 positioned on the upper portion of the core 75.

  In this embodiment, the notch-like flow down port 81 is used, but a hole-like flow down port may be used. Further, the oil guide piece 82 is formed integrally with the receiving portion 80 together with the formation of the flow-down port 81 by cutting and raising a part of the receiving portion 80 downward, but is formed separately from the receiving portion 80. It is also possible.

  In this lubrication mechanism, the lubricating oil flowing through the oil passage 57 of the casing 22 flows down from the oil hole 77 to the receiving portion 80 of the distribution plate 78. The lubricating oil that has flowed down to the receiving portions 80 of the distribution plate 78 is diverted to the respective flow-down ports 81 of the receiving portion 80 and flows down to the coils 76 of the stator 23 while being guided by the oil guide pieces 82 from the flow-down ports 81. The coil 76 of the stator 23 is cooled by the lubricating oil supplied from the downstream port 81 while being guided by the oil guide piece 82.

  As shown in FIG. 6, the opening area of the flow down port 81 located on both sides of the distribution plate 78 is larger than the opening area of the flow down port 81 at the center of the distribution plate 78 located immediately below the oil hole 77 of the oil passage 57. doing. As a result, the lubricating oil flowing down from the oil hole 77 and diverting to the both sides from the center of the receiving portion 80 of the distribution plate 78 is uniformly supplied to the coil 76 at the central downstream port 81 and the downstream downstream ports 81. I have to.

  In the flow-down port 81 at the center of the distribution plate 78 located directly below the oil hole 77 of the oil passage 57, the oil guide piece 82 is provided on the left side in the figure, but the oil guide piece may be provided on the right side in the figure. In addition, at the flow-down ports 81 located on both sides of the distribution plate 78, the oil guide piece 82 is provided on the upstream side where the lubricant flows down, but the oil guide piece may be provided on the downstream side where the lubricant flows down.

  As described above, in cooling the coil 76 of the stator 23, since the oil guide piece 82 is extended to the flow-down port 81 of the distribution plate 78, the lubricating oil flowing down from the flow-down port 81 is transferred to the stator 23 by the oil guide piece 82. Guided toward the coil 76. As a result, the lubricating oil does not flow down to the portion other than the coil 76 of the stator 23 along the lower surface of the receiving portion 80 of the distribution plate 78, and the flow rate of the lubricating oil supplied to the coil 76 does not decrease. .

  Therefore, the optimum amount of lubricating oil is reliably supplied to the coil 76 located below the flow-down port 81, and the coil 76 can be efficiently cooled by the lubricating oil. As a result, it is possible to suppress the output reduction and the efficiency deterioration of the electric motor 26 due to the magnetic force reduction of the core 75 based on the heat generation of the coil 76.

  In this embodiment, the distribution plate 78 having an L-shaped cross section including the fixing portion 79 and the receiving portion 80 is illustrated. However, as shown in FIG. 7, a wall facing the fixing portion 79 at the end of the receiving portion 80. It is also possible to use a distribution plate 78 having a concave section in which the portion 83 is erected. By adopting the distribution plate 78 having such a shape, it is possible to prevent the lubricating oil from leaking from the end portion of the receiving portion 80 and flowing down to a portion other than the coil 76 of the stator 23.

  On the other hand, as the lubrication of the speed reduction part B, the lubricating oil in the oil passage 63 flows out to the tooth surface of the first gear 30 via the oil passages 64 and 65 due to the centrifugal force and the pump pressure accompanying the rotation of the motor rotating shaft 25. The first gear 30 rotating at a high speed is lubricated. The first-stage second gear 31 and the second-stage third gear 32 and the fourth gear 33 are lubricated by splashing the lubricating oil stored in the lower part of the casing 22 in the speed reduction portion B.

  The lubricating oil that has cooled the drive unit A and lubricated the speed reduction unit B travels down the inner wall surface of the casing 22 due to gravity. The lubricating oil that has moved to the lower part of the drive part A flows into the lower part of the speed reducing part B from the oil drain hole 71 (see FIG. 3). The lubricating oil that has moved to and entered the lower portion of the speed reduction unit B is sucked up from the oil passage 58 of the casing 22 and returns to the suction port 69 of the rotary pump 56.

  In this embodiment, as shown in FIGS. 8 and 9, the electric vehicle 11 having the rear wheel 14 as a driving wheel is illustrated, but the front wheel 13 may be a driving wheel or a four-wheel driving vehicle. In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and includes, for example, a hybrid vehicle.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 21 In-wheel motor drive device 22 Casing 23 Stator 26 Electric motor 30-33 Gear 39 Parallel shaft gear reducer 46 Wheel bearing 57 Oil path 75 Core 76 Coil 77 Oil hole 78 Distribution plate 81 Downflow port 82 Oil guide piece A Drive part B Deceleration part C Bearing part

Claims (3)

A drive unit configured with an electric motor, a deceleration unit that decelerates and outputs the rotation of the drive unit, a bearing unit configured with a wheel bearing, a casing that houses the drive unit, and lubricating oil in the drive unit An in-wheel motor drive device comprising a lubrication mechanism for cooling the electric motor by supplying
The electric motor includes a stator fixed to the casing and having a coil wound around a core, and the lubrication mechanism is provided in an oil passage disposed in a core mounting portion of the casing, and the oil passage is provided in the oil passage. An oil hole that opens at a position above the coil, and a distribution plate that is disposed between the oil hole and the coil and that receives the lubricating oil flowing down from the oil hole. An in-wheel motor drive device characterized in that an oil guide piece extending downward is extended.   2. The stator according to claim 1, wherein the stator includes a plurality of coils disposed along an outer periphery of an annular core, and the distribution plate has an arc shape having a plurality of flow-down ports disposed corresponding to the coils. The in-wheel motor drive device of description.   3. The in-wheel motor drive device according to claim 1, wherein the distribution plate has a wall portion standing at an end portion of a receiving portion that receives the lubricating oil flowing down from the oil hole.

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