JP2016017606A - Wheel drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure necessary and sufficient durability and rigidity even if a spline length between an end part of an output shaft 28 and an annular plate 33a of a pin holder 33 cannot be secured sufficiently when separating the output shaft 28 of a reduction gear 20 and the annular plate 33 of the pin holder 33, and connecting the end part of the output shaft 28 and the annular plate 33a of the pin holder 33 by spline fitment.SOLUTION: An output shaft 28 arranged at an annular plate 33a at an outer side of a pin holder 33 is separated from the annular plate 33a, and formed as a different body, a spline which is spline-fit to an internal peripheral face of a hub ring 51 is formed at the hub ring 51 side of the output shaft 28, a spline which is spline-fit to the annular plate 33a of the pin holder 33 is formed at an end part of the output shaft 28 at a reduction gear side, and the spline at the reduction gear 20 side of the output shaft 28 is made larger in diameter than the spline at the hub ring 51 side of the output shaft 28. The surface pressure of a spline fitting portion is thereby lowered by increasing the number of teeth of the splines, and necessary and sufficient durability and rigidity can be secured.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a wheel drive device for driving a drive wheel of an automobile, and more particularly to an in-wheel motor drive device.

  As shown in FIG. 6, the wheel driving device B includes an electric motor 110, a speed reducer 120 that decelerates and outputs the rotation from the electric motor 110, and a wheel that is rotationally driven by the rotation from the speed reducer 120. The electric motor 110 and the speed reducer 120 have a motor casing 111 and a speed reducer casing 121, respectively. The motor casing 111 and the speed reducer casing 121 are arranged in the axial direction. Connected and partitioned by a partition 112.

  The electric motor 110 is of a radial gap type in which a stator 113 is provided on the inner peripheral surface of a motor casing 111 and a rotor 114 is provided at an interval on the inner periphery of the stator 113.

  The rotor 114 has a boss portion 115 in the center, and the boss portion 115 is inserted into a cylindrical portion 116 provided in the central portion of the partition wall 112 and is freely rotatable by a bearing 117 incorporated in the cylindrical portion 116. It is supported by.

  As shown in FIGS. 6 and 7, the speed reducer 120 is a cycloid speed reducer. The cycloid reduction gear 120 rotatably supports an external gear 124 by an eccentric shaft portion 123 provided on an input shaft 122, and external teeth 125 formed on the outer periphery of the external gear 124 are arranged inside the reduction gear casing 121. The internal gear 127 meshes with the internal tooth 127 of the built-in internal gear 126, the external gear 124 is caused to eccentrically swing by the rotation of the input shaft 122, and the rotation of the external gear 124 is output coaxially with the input shaft 122. 128 is output.

  Here, one end portion of the input shaft 122 is connected to the boss portion 115 of the rotor 114 by spline fitting and is rotated by the electric motor 110, and an eccentric shaft portion 123 is provided at the other end portion. It has been.

  As shown in FIG. 6, a pair of eccentric shaft portions 123 are provided in the axial direction of the input shaft 122, and the pair of eccentric shaft portions 123 are such that the center of the cylindrical outer diameter surface is 180 degrees out of phase in the circumferential direction. The bearings 129 are fitted to the outer diameter surfaces of the pair of eccentric shaft portions 123, respectively.

  As shown in FIGS. 6 and 7, the external gear 124 is rotatably supported by a bearing 129, and the external teeth 125 formed on the outer periphery thereof have a trochoidal curved tooth profile. In the external gear 124, a plurality of pin holes 130 are formed at equal intervals on one circle centered on the rotation axis, and the inner pins 131 are inserted into the pair of pin holes 130 arranged in the axial direction with a margin. A part of the outer periphery of the roller 132 rotatably supported by the inner pin 131 is in contact with a part of the inner periphery of the pin hole 130.

As shown in FIG. 6, the rollers 132 are needle roller bearings. The roller 132 enables the eccentric gear 124 to swing eccentrically, and the pin holder 133 that supports both ends of the inner pin 131 is rotated by the rotation of the outer gear 124 to output from the output shaft 128 connected to the pin holder 133. I try to let them.
Here, the pin holder 133 has a pair of annular plates 133a and 133b arranged to face each other in the axial direction, and the end portions of the inner pins 131 are supported by the pair of annular plates 133a and 133b. Reference numeral 133b is rotatably supported by a bearing 135 provided on the outer diameter surface of the input shaft 122.

  An output shaft 128 is formed integrally with the outer side annular plate 133 a disposed on the shaft end side of the input shaft 122.

  As shown in FIG. 7, the internal teeth 127 provided on the inner periphery of the internal gear 126 are formed by external pins, and the number of teeth of the internal teeth 127 is larger than that of the external teeth 125 of the external gear 124. As shown in FIG. 6, the internal gear 126 is configured to rotatably support both end portions of the inner teeth 127 formed of outer pins by a pair of flanges 138 formed inward from both ends of the cylindrical portion 137. Yes.

  The internal gear 126 is rotatably supported by a bearing 139 fitted to the outer diameter surfaces of the pair of annular plates 133a and 133b in the pin holder 133, and has a floating support having a gap with the inner diameter surface of the speed reducer casing 121. In addition, the derotator casing 121 is prevented from rotating by a detent means having an elastic support function.

  Further, a counterweight 140 is attached to the outside of each of the pair of eccentric shaft portions 123 provided on the input shaft 122 so as to balance the rotation of the input shaft 122.

  Further, a hub wheel 151 fitted and connected to the outer diameter surface of the output shaft 128 by a spline 158 so that torque can be transmitted, and an outer ring member 152 that rotatably holds the hub wheel 151 with respect to the reduction gear casing 121. Prepare. The hub wheel 151 of the wheel bearing portion 150 is provided with a small-diameter cylindrical portion 151a, and a bearing inner ring 151b is press-fitted into and integrated with the outer diameter surface of the small-diameter cylindrical portion 151a.

  As described above, by fitting the output shaft 128 and the hub wheel 151 by the spline 158, the output shaft 128 and the hub wheel 151 are relatively moved in the axial direction at the fitting portion by the spline 158. Can be made. Thereby, since the location which absorbs the vibration generate | occur | produced in an axial direction increases, generation | occurrence | production of noise can be prevented more effectively.

JP 2013-148198 A JP 2011-118557 A

  Incidentally, as described above, the internal gear 126 is rotatably supported by the bearing 139 fitted to the outer diameter surfaces of the cylindrical portions of the pair of annular plates 133 a and 133 b in the pin holder 133, so that the inner diameter of the speed reducer casing 121. Floating support having a gap with the surface is provided, and the rotation of the speed reducer casing 121 is prevented by rotation prevention means having an elastic support function.

  In the speed reducer 120 in which the internal gear 126 is floatingly supported on the speed reducer casing 121 by a detent means having an elastic support function, the degree of cylindricity of the speed reducer casing 121 that elastically supports the internal gear 126 and the elastic bushing that constitutes the elastic support function. The centering accuracy of the speed reducer 120 is determined by the coaxiality. For this reason, it is difficult to install the output shaft 128 of the speed reducer 120, the boss portion 115 of the electric motor 110, and the shaft center of the hub wheel 151 of the wheel bearing portion 150 on the same axis.

  If the output shaft 128 of the speed reducer 120, the boss portion 115 of the electric motor 110, and the shaft center of the hub wheel 151 of the wheel bearing portion 150 are misaligned, vibration is generated due to the effect of misalignment.

  In particular, in the conventional wheel drive device B shown in FIG. 6, the output shaft 128 of the speed reducer 120 is formed integrally with the annular plate 133 a on the outer side of the pin holder 133. It is difficult to install the boss part 115 of the electric motor 110 and the shaft center of the hub wheel 151 of the wheel bearing part 150 on the same core.

  In Patent Document 1 and Patent Document 2, an output shaft 128 integrated with the pin holder 133 of the speed reducer 120 is provided separately from the annular plate 133a of the pin holder 133, and the end of the output shaft 128 and the annular plate 133a of the pin holder 133 are provided. Have been disclosed which try to reduce the influence of misalignment by connecting them together by spline fitting.

  However, when the output shaft 128 integrated with the pin holder 133 of the speed reducer 120 is disconnected from the annular plate 133a of the pin holder 133 and the end of the output shaft 128 and the annular plate 133a of the pin holder 133 are connected by spline fitting. The axial length of the end portion of the output shaft 128 to be spline-fitted is the axial length of the annular plate 133a of the pin holder 133. Therefore, a necessary and sufficient length for ensuring durability and strength is set. There is a problem that you can not. On the other hand, if the axial length of the annular plate 133a is increased in order to ensure durability and strength, there arises a problem that the entire wheel drive device becomes large.

  Therefore, in order to suppress the occurrence of vibration, the present invention provides an output when the output shaft of the reducer is separated from the annular plate of the pin holder and the end of the output shaft and the annular plate of the pin holder are connected by spline fitting. Even if the spline length between the end portion of the shaft and the annular plate of the pin holder cannot be sufficiently ensured, it is intended to ensure the necessary and sufficient durability and strength.

  In order to solve the above problems, in the present invention, an electric motor, a reduction gear that reduces the rotation output from the rotor of the electric motor, and a hub wheel that transmits the rotation output from the reduction gear to the drive wheel The speed reducer is incorporated into an input shaft that is rotationally driven by the electric motor, an external gear that is rotatably supported by an eccentric shaft portion provided on the input shaft, and a speed reducer casing. The internal gear is formed with internal teeth that are prevented from rotating and meshed with the external teeth formed on the outer periphery of the external gear, and the internal gear has more teeth than the external teeth. A plurality of pin holes are formed at equal intervals on a circle centered on the rotation axis, and an inner pin is inserted into each of a pair of pin holes arranged in the axial direction with sufficient margin. The gear is eccentrically swung and its external gear A wheel that is a cycloid reducer that rotates a pin holder made of a pair of annular plates that support the end portions of the inner pins by rotation and outputs to a hub wheel from an output shaft provided on an annular plate on the outer side of the pin holder. In the drive device, an output shaft provided on the annular plate on the outer side of the pin holder is separated from the annular plate and formed as a separate member, and the spline is fitted to the inner peripheral surface of the hub wheel on the hub wheel side of the output shaft. A spline that fits into the pin holder annular plate is formed at the end of the output shaft on the reducer side, and the spline on the reducer side of the output shaft is larger than the spline on the hub wheel side of the output shaft. It is characterized by its diameter.

  In the in-wheel motor drive device according to the present invention, as described above, since the output shaft of the speed reducer is separated from the pin holder and separated, the output shaft of the speed reducer, the boss portion of the electric motor, and the wheel bearing The center misalignment between the central portion of the hub wheel is difficult to occur, thereby suppressing the occurrence of vibration. Moreover, by separating the spline from the pin holder and making the spline on the reducer side of the output shaft larger than the spline on the hub wheel side of the output shaft, the axial length of the spline provided separately on the annular plate of the pin holder is shortened. However, since the number of teeth of the spline on the speed reducer side of the output shaft can be increased more than the spline on the hub wheel side of the output shaft, necessary and sufficient durability and strength can be ensured.

It is a vertical front view of the wheel drive device concerning this invention. It is a vertical side view along the II-II line of FIG. It is an enlarged view of the output shaft part of a reduction gear. It is an exploded view of a wheel bearing part and an output shaft part of a reduction gear. It is an enlarged view of an oil pump. It is a vertical front view which shows a prior art example. FIG. 7 is a longitudinal side view taken along line VII-VII in FIG. 6.

  Hereinafter, an embodiment in which the wheel drive device A of the present invention is applied to an in-wheel motor drive device will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the in-wheel motor drive device includes an electric motor 10, a speed reducer 20 that decelerates and outputs rotation from the electric motor 10, and a wheel that is rotationally driven by rotation from the speed reducer 20. And a wheel bearing portion 50 that rotatably supports the motor, and is installed inside the wheel of the driving wheel of the automobile.

  The electric motor 10 and the speed reducer 20 each have a motor casing 11 and a speed reducer casing 21, and the motor casing 11 and the speed reducer casing 21 are connected in the axial direction and partitioned by a partition wall 12.

  The electric motor 10 is of a radial gap type in which a stator 13 is provided on the inner peripheral surface of a motor casing 11 and a rotor 14 is provided at an interval on the inner periphery of the stator 13.

  The rotor 14 has a boss portion 15 in the center, and one end of the boss portion 15 is inserted into a cylindrical portion 16 provided in the central portion of the partition wall 12, and a rolling bearing 17 incorporated in the cylindrical portion 16. Is rotatably supported by. The other end of the boss portion 15 is rotatably supported on the rear cover of the motor casing 11 by another rolling bearing 17.

  As shown in FIGS. 1 and 2, the speed reducer 20 is a cycloid speed reducer. The cycloid speed reducer 20 rotatably supports an external gear 24 by an eccentric shaft portion 23 provided on an input shaft 22, and external teeth 25 formed on the outer periphery of the external gear 24 are connected to the speed reducer casing 21. The external gear 24 is eccentrically oscillated by the rotation of the input shaft 22 and meshed with the internal teeth 27 of the internal gear 26 incorporated inside, and the rotation of the external gear 24 is arranged coaxially with the input shaft 22. The output is output from the output shaft 28.

  Here, one end portion of the input shaft 22 is connected to the boss portion 15 of the rotor 14 by spline fitting, and is rotated by the electric motor 10, and an eccentric shaft portion 23 is provided at the other end portion. It has been.

  As shown in FIG. 1, a pair of eccentric shaft portions 23 are provided in the axial direction of the input shaft 22, and the pair of eccentric shaft portions 23 is such that the center of the cylindrical outer diameter surface is 180 degrees out of phase in the circumferential direction. A rolling bearing 29 is fitted to the outer diameter surfaces of the pair of eccentric shaft portions 23.

  As shown in FIG. 2, the external gear 24 is rotatably supported by a rolling bearing 29, and the external teeth 25 formed on the outer periphery thereof have a trochoidal curved tooth profile. In the external gear 24, a plurality of pin holes 30 are formed at equal intervals on one circle centered on the rotation axis, and the inner pins 31 are inserted into the pair of pin holes 30 arranged in the axial direction with a margin. The outer peripheral part of the roller 32 rotatably supported by the inner pin 31 is in contact with the inner peripheral part of the pin hole 30.

  As shown in FIG. 2, the roller 32 consists of a needle roller bearing. The roller 32 enables the eccentric gear 24 to swing eccentrically, and the external gear 24 meshes with the internal teeth 27 of the internal gear 26 while revolving, thereby causing a rotational movement in the opposite direction to the revolving movement. The pin holder 33 that supports both ends of the inner pin 31 is rotated by the rotation of the external gear 24 so that the output is output from the output shaft 28 connected to the pin holder 33.

  Here, the pin holder 33 has a pair of annular plates 33a and 33b arranged opposite to each other in the axial direction, and supports the end portion of the inner pin 31 by the pair of annular plates 33a and 33b. , 33b are rotatably supported by rolling bearings 35 provided on the outer diameter surface of the input shaft 22, respectively.

  The annular plate 33a of the pin holder 33 and the output shaft 28 that is spline-fitted to the hub wheel 51 are formed separately. Of the annular plates 33a and 33b of the pin holder 33, the end portion on the reduction gear 20 side (inner side) of the output shaft 28 is inserted into the annular plate 33a on the outer side, as shown in FIGS. A cylinder part is provided. A female spline 28a is formed on the inner peripheral surface of the cylindrical portion, and a male spline 28b that is spline-fitted to the female spline 28a is formed at the end of the output shaft 28 on the speed reducer 20 side. The shaft 28 is connected.

  A male spline 58 b that is spline-fitted to a female spline 58 a formed on the inner peripheral surface of the hub wheel 51 is formed at the outer end of the output shaft 28. Here, when the in-wheel motor device is mounted on the vehicle, the inner side is referred to as the inner side near the center of the vehicle body and the outer side near the outer side of the vehicle body.

  As described above, the output shaft 28 and the hub wheel 51 can be relatively moved in the axial direction by making the fitting between the output shaft 28 and the hub wheel 51 a spline fitting. Thereby, since the location which absorbs the vibration generate | occur | produced in an axial direction increases, generation | occurrence | production of noise can be prevented more effectively.

  As described above, the output shaft 28 provided in the pin holder 33 of the speed reducer 20 is provided separately from the outer annular plate 33a of the pin holder 33. The output shaft 28 and the pin holder 33 The annular plate 33a is connected by spline fitting.

  As shown in FIGS. 3 and 4, the output shaft 28 is formed with a male spline 58 b fitted to a female spline 58 a formed on the inner peripheral surface of the hub wheel 51 at the outer end, and an inner end. The large-diameter portion 28c is formed with a male spline 28b that fits into the female spline 28a of the annular plate 33a of the pin holder 33.

  That is, the inner side male of the output shaft 28 fitted to the female spline 28a of the annular plate 33a of the pin holder 33 is larger than the diameter of the outer side male spline 58b of the output shaft 28 fitted to the female spline 58a of the hub wheel 51. The spline diameter of the spline 28b is made larger. Each of the outer male spline 58b and the inner male spline 28b of the output shaft 28 is induction hardened to have a surface height of HRC 57 to 64. The female spline 58a of one hub wheel 51 and the female spline 28a of the annular plate 33a of the pin holder 33 are not subjected to quenching treatment.

  The spline fitting length between the male spline 28b at the inner end of the output shaft 28 and the female spline 28a of the annular plate 33a of the pin holder 33 is the same as that of the cylindrical portion of the annular plate 33a of the pin holder 33 provided with the female spline 28a. Limited to axial length. The axial length of the cylindrical portion of the annular plate 33a of the pin holder 33 cannot be set longer in order to reduce the size, but as described above, the diameter of the male spline 28b of the output shaft 28 on the speed reducer 20 side. By making the diameter larger than the diameter of the male spline 28b of the output shaft 28 fitted to the hub wheel 51, the number of teeth of the spline can be increased to reduce the surface pressure of the spline fitting portion. As a result, necessary and sufficient durability and strength can be ensured.

  It is also possible to adjust the surface pressure of the spline by changing the module of the spline, such as making the number of teeth and the tooth trace shape of the female spline 28a and the male spline 28b into an arc.

  The spline tooth length in the spline diameter with respect to the spline diameter is determined so that the allowable transmission torque of the inner side spline of the output shaft 28 is equal to the allowable transmission torque of the output shaft 28 on the hub wheel 51 side.

  The female spline 28a of the annular plate 33a of the pin holder 33 needs to have a smaller diameter than the outer ring of the rolling bearing 35 that supports the pin holder 33 in order to perform broaching.

  As shown in FIG. 3, the inner end of the output shaft 28 is arranged so that the output shaft 28 separated from the pin holder 33 contacts the rolling bearing 35 that supports the pin holder 33 by spline fitting and does not generate vibration or the like. It is preferable to restrain the movement of the output shaft 28 in the axial direction by a retaining ring 38.

  As shown in FIG. 2, the internal teeth 27 provided on the inner periphery of the internal gear 26 are formed from external pins to form an arc tooth shape, and the number of teeth of the internal teeth 27 is larger than the external teeth 25 of the external gear 24. It has become. As shown in FIG. 1, the internal gear 26 is rotatably supported by an external pin housing 37 at both ends of an internal tooth 27 formed of an external pin.

  The outer pin housing 37 is floatingly supported on the inner diameter surface of the speed reducer casing 21 via a detent means having an elastic support function, and the pin holder 33 is connected to the inner diameter surfaces of both ends of the outer pin housing 37 via the rolling bearings 36. The annular plates 33a and 33b are rotatably supported.

  A counterweight 40 is attached to the outside of each of the pair of eccentric shaft portions 23 provided on the input shaft 22. The counterweight 40 is arranged 180 degrees out of phase with the pair of eccentric shaft portions 23 to cancel out the unbalanced inertia couple caused by the rotation of the external gear.

  As shown in FIGS. 3 and 4, a small-diameter cylindrical portion 51a is provided in the hub wheel 51 of the wheel bearing portion 50, and a bearing inner ring 51c is press-fitted into the outer diameter surface of the small-diameter cylindrical portion 51a to be integrated.

  As shown in FIG. 1, the reducer casing 21 is provided with an oil tank 41 of lubricating oil at the lower portion, and the oil in the oil tank 41 is sucked in by an oil pump 42 provided in the partition wall 12. Lubricating oil is supplied to the speed reducer 20 to perform lubrication and cooling.

  An oil supply passage 43 that supplies lubricating oil to the inside of the electric motor 10 and the speed reducer 20 is provided from the discharge port of the oil pump 42 that is driven by using the output rotation of the speed reducer 20 that decelerates the rotation of the electric motor 10 to the motor casing. 11, an outer diameter channel 43a extending rearward along the inner side of the motor 11, a rear cover channel 43b provided in a rear cover on the rear surface of the motor casing 11, an internal channel 44 of the boss 15, and an input shaft of the speed reducer 20. 22 through the internal passage 45 of the speed reducer 20 and the suction passage 46 extending from the oil tank 41 to the suction port of the oil pump 42.

  The lubricating oil supplied from the oil pump 42 is guided into the motor casing 11 of the electric motor 10 from the radial oil holes 44 a provided in the internal passage 44 of the boss portion 15, and lubricates and cools the electric motor 10. Then, the oil tank 41 is discharged from below the motor casing 11 on the electric motor 10 side.

  Further, an oil hole 45a is also provided in the radial direction in the internal passage 45 of the input shaft 22 of the speed reducer 20, and lubricating oil is scattered from the oil hole 45a by centrifugal force, thereby lubricating and cooling the inside of the speed reducer 20. . That is, a so-called axial oil supply system is adopted.

  The return path for the lubricating oil is constituted by a discharge port 47 provided at the bottom of the speed reducer casing 21 of the speed reducer 20 and an oil tank 41.

  As shown in FIG. 5, the oil pump 42 includes an inner rotor 72 that rotates using the rotation of the speed reducer 20, an outer rotor 73 that rotates following the rotation of the inner rotor 72, a pump chamber 74, and a suction chamber. The cycloid pump includes a suction port 75 communicating with the passage 46 and a discharge port 76 communicating with the oil supply passage 43.

  Inner rotor 72 has a tooth profile formed of a cycloid curve on the outer diameter surface. Specifically, the shape of the tooth tip portion 72a is an epicycloid curve, and the shape of the tooth gap portion 72b is a hypocycloid curve. The inner rotor 72 is connected to the inner side annular plate 33 b of the pin holder 33 and rotates integrally with the pin holder 33 that rotates the output shaft 28 of the speed reducer 20.

  The outer rotor 73 has a tooth profile formed of a cycloid curve on the inner diameter surface. Specifically, the shape of the tooth tip portion 73a is a hypocycloid curve, and the shape of the tooth gap portion 73b is an epicycloid curve. The outer rotor 73 is rotatably supported by the pump case 77.

  The inner rotor 72 rotates around the rotation center c1. On the other hand, the outer rotor 73 rotates around a rotation center c2 different from the rotation center c1 of the inner rotor. Further, 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 = 5.

  A plurality of pump chambers 74 are provided in the space between the inner rotor 72 and the outer rotor 73. When the inner rotor 72 rotates using the rotation of the output shaft 28 of the speed reducer 20, the outer rotor 73 rotates in a driven manner. At this time, since the inner rotor 72 and the outer rotor 73 rotate around different rotation centers c1 and c2, the volume of the pump chamber 74 continuously changes. As a result, the lubricating oil flowing in from the suction port 75 is pumped from the discharge port 76 to the oil supply passage 43.

  As shown in FIG. 1, the reduction gear casing 21 is provided with an oil tank 41 for lubricating oil at the lower portion, and the lubricating oil in the oil tank 41 is sucked by the oil pump 42 through the suction passage 46, and the electric motor 10 and the reduction gear. Lubricating oil is supplied to 20 for lubrication and cooling.

  As shown in FIGS. 1 and 4, the wheel bearing portion 50 includes a hub wheel 51 fitted and connected to the outer diameter surface of the output shaft 28 in a state where torque can be transmitted by a spline, and the hub wheel 51 connected to the reduction gear casing 21. The outer ring member 52 is rotatably held with respect to the outer ring member 52, and the double-row rolling elements 53 are installed between the hub ring 51 and the outer ring member 52. The hub wheel 51, the inner ring member 51b, the outer ring member 52, and the double row rolling elements 53 installed therebetween constitute a double row angular ball bearing. The hub wheel 51 is integrally provided with a wheel mounting flange portion 54. A small-diameter cylindrical portion 51a is formed on the inner side of the hub wheel 51, and an inner ring member 51b forming an inner raceway ring of the double-row angular ball bearing is fitted on the outer surface of the small-diameter cylindrical portion 51a. The end of the portion 51a is coupled and integrated with the end of the inner ring member 51b by expanding caulking.

  In the above embodiment, the electric motor 10 is of a radial gap type in which the stator 13 is provided on the inner peripheral surface of the motor casing 11 and the rotor 14 is provided at an interval on the inner periphery of the stator 13. Although the example which showed was shown, the motor of arbitrary structures is applicable not only to this but. For example, an axial gap motor in which the stator and the rotor are arranged to face each other via a gap opened in the axial direction may be used.

  In the above-described embodiment, an example of the in-wheel motor drive device has been shown as the wheel drive device A that drives the drive wheels of the automobile. However, the present invention is not limited to this, and the wheel drive device A is used as a suspension member on the vehicle body side. It is also applicable as a so-called on-board drive device in which a pair of left and right drive wheels are driven by a drive shaft such as a constant velocity joint.

  Furthermore, the electric vehicle equipped with the wheel drive device A according to the present invention may have the rear wheels as drive wheels, the front wheels as drive wheels, or a four-wheel drive vehicle. In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and should be understood as including, for example, a hybrid vehicle.

DESCRIPTION OF SYMBOLS 10: Electric motor 11: Motor casing 12: Partition 13: Stator 14: Rotor 15: Boss part 16: Cylindrical part 17: Rolling bearing 20: Reduction gear 21: Reduction gear casing 22: Input shaft 23: Eccentric shaft part 24: Outer Gear 25: External tooth 26: Internal gear 27: Internal tooth 28: Output shaft 28a: Female spline 28b: Male spline 28c: Large diameter portion 29: Bearing 30: Pin hole 31: Inner pin 33: Pin holder 33a: Annular plate 33b: Annular plate 34a: Annular plate 35: Rolling bearing 36: Rolling bearing 37: Outer pin housing 38: Retaining ring 40: Counterweight 41: Oil tank 42: Oil pump 43: Oil supply passage 43a: Outer diameter channel 43b: Rear cover flow Path 44: Internal passage 44a: Oil hole 45: Internal passage 45a: Oil hole 46: Suction passage 47: Discharge port 50: Wheel bearing part 51: Hub wheel 51a: Small diameter cylindrical part 51b: Inner ring member 51c: Bearing inner ring 52: Outer ring member 53: Rolling element 54: Wheel mounting flange part 58a: Female spline 58b: Male spline 72: Inner rotor 72a: Tooth tip Part 72b: tooth gap part 73: outer rotor 73a: tooth tip part 73b: tooth gap part 74: pump chamber 75: suction port 76: discharge port 77: pump case A: wheel drive device

Claims (4)

  An electric motor, a speed reducer that decelerates the rotation output from the rotor of the electric motor, and a hub wheel that transmits the rotation output from the speed reducer to the drive wheel. The speed reducer is driven by the electric motor. An input shaft that is driven to rotate, an external gear that is rotatably supported by an eccentric shaft portion provided on the input shaft, and a rotation gear that is incorporated in the reducer casing and is prevented from rotating, and is formed on the outer periphery of the outer gear. An internal gear with which the external teeth are meshed is formed, and the internal gear has a larger number of internal teeth than the external teeth, and the external gear includes a plurality of teeth on a circle centered on the rotation axis. Are formed at equal intervals, an inner pin is inserted into each of a pair of pin holes arranged in the axial direction with sufficient margin, and the outer gear is eccentrically swung by the rotation of the input shaft. A pair of annular plates that support the end of the inner pin by rotation In a wheel drive device that is a cycloid reduction gear that rotates a pin holder consisting of the pin holder and outputs to a hub wheel from an output shaft provided on an annular plate on the outer side of the pin holder, provided on the annular plate on the outer side of the pin holder The output shaft is separated from the annular plate and formed separately, and a spline is formed on the hub wheel side of the output shaft to be splined to the inner peripheral surface of the hub wheel. A wheel drive device characterized in that a spline that is spline-fitted on an annular plate of the pin holder is formed, and the spline on the speed reducer side of the output shaft is larger in diameter than the spline on the hub wheel side of the output shaft.   The wheel drive device according to claim 1, wherein the spline on the speed reducer side of the output shaft has more teeth than the spline on the hub wheel side of the output shaft.   The wheel drive device according to claim 1 or 2, wherein an end portion of the output shaft on the speed reducer side and an annular plate of the pin holder are coupled by a retaining ring.   2. The length of the spline streak direction relative to the spline diameter is determined so that an allowable transmission torque due to the spline on the hub wheel side of the output shaft is equal to an allowable transmission torque due to the spline on the reduction gear side of the output shaft. The wheel drive device in any one of -3.

Images