JP2016148411A - Wheel drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel drive unit which can supply a lubricant even at a start of startup from a stop of a vehicle.SOLUTION: A wheel drive unit comprises: a motor part A having a motor rotating shaft 24a; a reduction gear B which decelerates the rotation of the motor rotating shaft 24a, and outputs it; a casing 22 for accommodating the motor part A and the reduction gear B; an oil tank arranged below the casing 22; and an oil pump 42 which sucks a lubricant from the oil tank, supplies the lubricant to the motor part A and the reduction gear B, and performs the lubrication and cooling of the motor part A and the reduction gear B. The wheel drive unit drives wheels by an output of the reduction gear, and comprises a casing oil passage extending to a rear part along the inside of the casing of the motor part A from a discharge port of the oil pump 42, and an internal passage 44 which is connected to the casing oil passage, and arranged at the motor rotating shaft 24a. An inlet side of the casing oil passage connected to the discharge port of the oil pump is arranged while being directed downward from a horizontal plane, and an outlet side connected to the internal oil passage 44 of the casing oil passage is directed upward from the horizontal plane.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a wheel drive device, and more particularly to a lubricating structure for a wheel drive device of an electric vehicle.

  In a wheel drive device that uses an electric motor as a drive source and decelerates the rotation of the electric motor with a speed reducer to rotate the drive wheel, the rotation of the output shaft of the speed reducer is transmitted to a hub wheel provided on the output shaft. The in-wheel motor system is configured to drive the drive wheel supported by the hub wheel, and the drive shaft is connected to the output shaft of the speed reducer via a joint to transmit the rotation of the drive shaft to the hub wheel. There is an on-board system that drives a drive wheel.

  The structure of the in-wheel motor system will be described. FIG. 12 is a longitudinal front view of a conventional in-wheel motor drive device. As shown in FIG. 12, the in-wheel motor drive device 121 has a motor part A that generates a driving force, a speed reducer B that decelerates and outputs the rotation of the motor part A, and an output from the speed reducer B as driving wheels. And a wheel hub C to be transmitted to the vehicle.

  The motor part A and the speed reducer B are accommodated in the casing 122. The casing 122 is partitioned by a partition wall 122c into a casing 122a on the motor part A side and a casing 122b on the reduction gear B side.

  The motor part A uses a radial gap type of which a stator 123 is provided on the inner peripheral surface of the casing 122a and a rotor 124 is provided at an interval on the inner periphery of the stator 123.

  The rotor 124 has a motor shaft 124a in the center. The motor shaft 124a is connected to the input shaft 130 of the speed reducer B and is inserted into the casing 122b of the speed reducer B. The bearings 125a and 125b are used for the casing 122a. And is supported rotatably.

  The casing 122b of the speed reducer B is provided with an oil tank 141 for lubricating oil at the lower part. The lubricating oil in the oil tank 141 is sucked by the oil pump 142, and the lubricating oil is distributed to the motor unit A and the speed reducer B for lubrication. And cooling is performed (Patent Document 1).

  The oil supply passage for supplying the lubricating oil to the inside of the motor part A and the speed reducer B is from the discharge port of the oil pump 142 driven using the output rotation of the speed reducer B that reduces the rotation of the motor part A to the casing 122a. The outer diameter part flow path 143a extending rearward along the inner side of the outer diameter part, the rear cover flow path 143b provided in the rear cover 122d, the inner path 144 of the motor shaft 124a, and the inside of the input shaft 130 of the speed reducer B A passage provided through the passage 145 into the casing 122b of the reduction gear B, a radial oil hole 144a provided in the internal passage 144 of the motor shaft 124a, and a radius provided in the casing 122a of the motor portion A and the input shaft 130. Direction oil hole 130a is guided into the casing 122b of the reduction gear B, from the oil tank 141 below the casing 122b of the reduction gear B. Constituted by a suction passage 146 leading to the inlet of the-pumped 142, a so-called axial lubrication system is adopted.

  The lubricating oil scattered in the casing 122 a of the motor part A cools and lubricates each part, then gathers in the lower part through the inner wall of the casing 122 a, and returns to the oil tank 141 through the communication hole 148.

  Further, the lubricating oil scattered in the casing 122b of the reduction gear B is lubricated and cooled, and then gathers in the lower part through the inner wall of the casing 122b. The oil tank is discharged from the outlet 149 provided in the lower part of the casing 122b. Reflux to 141.

  Incidentally, as the oil pump 142, there is an oil pump that uses an output rotation of the electric motor A or the speed reducer B, for example, that uses a cycloid pump (see Patent Document 1). In the example of FIG. 12, the oil pump 142 is driven by the output rotation of the speed reducer B.

  When using the oil pump 142 that is driven by the internal rotational force, there is an advantage that no external driving force (power source or the like) is required.

  FIG. 13 is a cross-sectional view taken along line EE in FIG. 12. As shown in FIG. 13, the discharge passage 147 that connects the discharge port 176 of the oil pump 142 to the outer diameter channel 143 a is connected to the discharge port 176. It extends vertically upward. The suction passage 146 to the suction port 175 of the oil pump 142 is located on a line perpendicular to the discharge passage 147 and extends downward.

  Since the discharge passage 147 is arranged to extend vertically upward, the distance for pushing up the lubricating oil becomes long, and the loss increases accordingly.

Japanese Patent Laid-Open No. 2006-240429

  Since the oil pump 142 is driven by using the output rotation of the electric motor A and the speed reducer B, the rotational speed of the oil pump 142 is determined by the driving state. For this reason, when starting from the stop, the rotation speed of the oil pump 142 is low, sufficient negative pressure is not generated, it takes time to push the lubricating oil up to the discharge passage 147, and it takes time to start lubrication. There was a problem. When running for a long time in a non-lubricated state in which no lubricating oil is supplied, for example, running at a high speed such as climbing at an extremely low speed, there are concerns about problems such as seizure and locking of the rotating part in the worst case.

  Therefore, the present invention is intended to provide a wheel drive device that can supply lubricating oil even when the vehicle starts from the stop and also reduces the load on the oil pump and improves the power consumption.

  In order to solve the above-described problems, the present invention accommodates a motor unit having a motor rotation shaft that outputs rotation, a speed reducer that decelerates and outputs the rotation of the motor rotation shaft, and the motor unit and the speed reducer. The casing, the oil tank provided below the casing, and the inner rotor rotate to suck the lubricating oil from the oil tank and supply the lubricating oil to the motor unit and the reduction gear to lubricate and cool the motor portion and the reduction gear. An oil pump for driving, and a wheel driving device for driving a wheel by an output of a speed reducer, wherein a casing oil passage extending rearward along the inside of the casing of the motor unit from the discharge port of the oil pump, An internal passage provided in the motor rotation shaft connected to the casing oil passage, and an inlet side of the casing oil passage connected to the discharge port of the oil pump is directed downward from the horizontal. It provided Te, an outlet side leading to the internal passageway of the casing oil passage and being provided facing above the horizontal.

  The vehicle drive device according to claim 1, wherein the casing oil passage is provided below a rotation axis of the inner rotor.

  The casing oil passage may be arranged on the front side in the vehicle traveling direction.

  What is necessary is just to comprise the said oil pump so that it may drive by rotation of the said motor part or rotation of a reduction gear.

  The oil pump can be a cycloid pump.

  When a cycloid pump is used as the oil pump, a one-way clutch that transmits rotation only when the rotation shaft rotates in the rotation direction of driving as the oil pump may be provided on the rotation shaft.

  In the vehicle drive device according to the present invention, the inlet side of the discharge passage connected to the discharge port of the oil pump is provided downward from the horizontal, and the discharge passage extends obliquely downward. Lubricating oil discharged from the discharge port is sent downward, so that a large negative pressure is not required, and the lubricating oil can be immediately supplied from the casing oil passage to the motor unit and the speed reducer. Furthermore, since the load of the oil pump is reduced, the electricity cost can be improved.

It is a front view of a drive wheel provided with an in-wheel motor drive device as a vehicle drive device concerning an embodiment of this invention. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is CC sectional view taken on the line of FIG. It is the DD sectional view taken on the line of FIG. It is an enlarged vertical sectional view of a reduction gear. It is a vertical side view along the III-III line of FIG. It is an enlarged view of an oil pump. (A) shows the power transmission state of a one-way clutch, (b) is the schematic which shows the power interruption state of a one-way clutch. FIG. 2 is a schematic plan view of an electric vehicle having the drive wheel of FIG. 1. It is the figure which looked at the electric vehicle of FIG. 10 from back. It is a vertical front view which shows a prior art example. It is the EE sectional view taken on the line of FIG.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 10, an electric vehicle 11 including a vehicle drive device including an in-wheel motor drive device according to an embodiment of the present invention includes a chassis 12, front wheels 13 as steering wheels, and drive wheels (rear wheels). ) 14 and an in-wheel motor drive device 21 that transmits a drive force to each of the left and right drive wheels 14. As shown in FIG. 11, the drive wheel 14 is accommodated in the wheel housing 12a of the chassis 12, and is fixed to the lower part of the chassis 12 via a suspension device (suspension) 12b. As a mounting form of the in-wheel motor drive device 21, in addition to the rear wheel drive system shown in FIGS. 10 and 11, either the front wheel drive system or the four wheel drive system may be used.

  The suspension device 12b supports the drive wheel 14 by a suspension arm that extends to the left and right, and suppresses vibration of the chassis 12 by absorbing vibration received by the drive wheel 14 from the ground by a strut including a coil spring and a shock absorber. Furthermore, a stabilizer that suppresses the inclination of the vehicle body when turning or the like is provided at a connecting portion of the left and right suspension arms. The suspension device 12b is an independent suspension type in which the left and right wheels can be moved up and down independently in order to improve the followability to the road surface unevenness and efficiently transmit the driving force of the driving wheels to the road surface. Is desirable.

  The electric vehicle 11 needs to be provided with a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 12 by providing an in-wheel motor drive device 21 that drives the left and right drive wheels 14 inside the wheel housing 12a. This eliminates the need to secure a wide cabin space and control the rotation of the left and right drive wheels.

  1 is a front view showing the drive wheel 14, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is a cross-sectional view taken along line BB in FIG. FIG. 3 shows a state in which the in-wheel motor drive device 21 is cut at an angle of 30 degrees from the horizontal direction, and the front is inclined lower toward the traveling direction. 1 and 2 schematically show the ground on which the wheels are grounded so that the horizontal direction can be easily understood.

  As shown in FIGS. 1 and 2, the drive wheel 14 includes an in-wheel motor drive device 21 inside a wheel 14a, and a tire 14b is mounted on the wheel 14a.

  As shown in FIGS. 2 and 3, the in-wheel motor drive device 21 includes a motor part A that generates a driving force, a speed reducer B that decelerates and outputs the rotation of the motor part A, and an output from the speed reducer B. The motor hub A and the speed reducer B are housed in the casing 22 and are mounted in the wheel housing 12a of the electric vehicle 11 as shown in FIG. The motor part A and the speed reducer B are accommodated in the casing 22.

  The wheel hub C has a wheel mounting flange portion 84 for attaching a wheel 14 a fixedly connected to the output shaft 33. The wheel 14 a is fixedly connected by a wheel mounting bolt 14 c provided on the wheel mounting flange portion 84. A brake disc 15 is mounted between the wheel mounting flange portion 84 and the wheel 14a.

  The in-wheel motor drive device 21 will be further described with reference to FIGS. 2 and 3.

  The motor part A and the speed reducer B are accommodated in the casing 22. The casing 22 is formed by a casing 22 a on the motor part A side, a casing 22 b on the reduction gear B side, a partition wall 22 c that partitions the casings 22 a and 22 b, and a rear cover 22 d that is attached to the rear surface of the casing 22. .

  At the center of the partition wall 22c, a through portion is formed through which the motor rotating shaft 24a of the motor portion A is inserted. A through portion through which the output shaft 33 is inserted is formed in the front wall of the casing 22b on the reduction gear B side. A rolling bearing 90 with a seal is provided between the through-hole provided in the front wall of the casing 22b on the reduction gear B side and the output shaft 33. When the wheel hub C is replaced, the lubricating oil in the reduction gear B leaks out. In addition, the intrusion of dust into the speed reducer B is prevented. An oil pump 42 is provided on the partition wall 22 c of the motor part A.

  The motor part A uses a radial gap type in which a stator 23 is provided on the inner peripheral surface of the casing 22a, and a rotor 24 is provided at an interval on the inner periphery of the stator 23.

  The rotor 24 has a motor rotation shaft 24a in the center, and the motor rotation shaft 24a is connected to the input shaft 30 of the speed reducer B and inserted into the casing 22b of the speed reducer B, and the casing 22 is supported by bearings 25a and 25b. Is supported so as to be freely rotatable.

  The casing 22b of the speed reducer B is provided with an oil tank 41 for lubricating oil at the lower portion. The lubricating oil in the oil tank 41 is sucked by the oil pump 42 through the suction passage 46, and is supplied to the motor unit A and the speed reducer B. Supply, lubrication and cooling.

  The lubricating oil passage of the in-wheel motor drive device 21 includes an oil supply passage 43a having an outer diameter extending from the discharge port of the oil pump 42 to the rear along the inside of the casing 22a via the discharge passage 48, and a rear cover on the back surface of the casing 22a. A rear cover passage 43b provided in 22d, an internal passage 44 of the motor rotation shaft 24a, an internal passage 45 of the input shaft 30 of the reduction gear B, a discharge port 49 provided in a lower portion of the casing 22b of the reduction gear B, a deceleration It is mainly constituted by a suction passage 46 extending from the discharge port of the oil tank 41 below the bottom of the casing 22b of the machine B to the suction port of the oil pump 42. In this embodiment, a casing oil passage is constituted by the discharge passage 48, the oil supply passage 43a, and the rear cover passage 43b.

  The lubricating oil supplied by the oil pump 42 is scattered by the centrifugal force and the pressure of the oil pump 42 from the radial oil holes 44a provided in the internal passage 44 of the motor rotating shaft 24a, and becomes the splashed lubricating oil. Is guided into the casing 22a of the motor part A. The lubricating oil scattered in the casing 22a of the motor part A cools and lubricates each part, then gathers in the lower part through the inner wall of the casing 22a, and returns to the oil tank 41 from the communication hole 47 provided in the partition wall 22c. To do.

  In addition, oil holes 45a and 45b are also provided in the internal passage 45 of the input shaft 30 of the speed reducer B in the radial direction, and the lubricating oil scatters from the oil holes 45a and 45b due to the centrifugal force and the pressure of the oil pump 42. A so-called axial center oil supply system that lubricates and cools the inside of the machine B is adopted. Lubricating oil scattered in the casing 22b of the reducer B is lubricated and cooled in each part, and then gathers in the lower part through the inner wall of the casing 22b, and enters the oil tank 41 from the discharge port 49 provided in the lower part of the casing 22b. Reflux.

  Next, with reference to FIG.4 and FIG.5, the lubricating oil path of the in-wheel motor drive device 21 is further demonstrated. 4 is a cross-sectional view taken along the line CC in FIG. 2, and FIG. 5 is a cross-sectional view taken along the line DD in FIG.

  As shown in FIG. 4, the inlet side of the discharge passage 48 connected to the discharge port 76 of the oil pump 42 is provided facing downward from the horizontal, and the discharge passage 48 extends obliquely downward, and is an outer diameter portion located on the lower side. Is connected to the oil supply passage 43a. The suction passage 46 reaching the suction port 75 of the oil pump 42 is connected by extending vertically from below to above.

  As shown in FIG. 5, the rear cover passage 43b connected to the internal passage 44 provided on the motor rotation shaft 24a is provided with the outlet side connected to the internal passage 44 of the motor rotation shaft 24a facing upward from the horizontal. That is, the rear cover passage 43b extends obliquely upward from the oil supply passage 43a, and the outlet side connected to the internal passage 44 is disposed above the horizontal.

  As shown in FIGS. 4 and 5, the casing oil passage composed of the discharge passage 48, the oil supply passage 43a, and the rear cover passage 43b is located below the rotation axis of the oil pump 42, that is, the rotation axis of the inner rotor. Is provided.

  As described above, the inlet side of the discharge passage 48 connected to the discharge port 76 of the oil pump 42 is provided facing downward from the horizontal, and the discharge passage 48 extends obliquely downward. The lubricating oil discharged from the discharge port 76 is sent downward. As a result, a large negative pressure is not required, and the lubricating oil is immediately sent from the casing oil passage to the internal passage 44 of the motor rotating shaft 24a, and the lubricating oil is supplied to the motor unit A and the speed reducer B. Further, the casing oil passage composed of the discharge passage 48, the oil supply passage 43a, and the rear cover passage 43b is provided below the rotational axis of the inner rotor of the oil pump 42, and therefore the distance that pushes the lubricating oil upward. Therefore, the load on the oil pump 42 is reduced, and the electricity cost is improved. And considering that the distance in the vertical direction of the casing oil passage is short and the lubricating oil can be held, the discharge passage 48 and the rear cover passage 43b are preferably arranged obliquely at an angle of 30 degrees from the horizontal.

  Further, as shown in FIG. 4, the oil supply passage 43a is disposed at a position on the front side in the traveling direction, so that the lubricating oil passing therethrough can be efficiently cooled. The casing oil passage composed of the discharge passage 48, the oil supply passage 43a, and the rear cover passage 43b is provided below the rotational axis of the inner rotor of the oil pump 42, so that the lubricating oil in the casing oil passage falls downward. Even when starting from a state of being stopped for a long time, lubricating oil can be immediately supplied to each sliding portion, and wear of the sliding surface can be prevented.

  After stopping for a long time, the oil has run out and the sliding surface has run out of oil film. The risk of damage increases because the sliding surface is in metal contact until the lubricating oil is supplied, but the risk of damage can be reduced by shortening the time between them.

  As shown in FIG. 8, the oil pump 42 of this embodiment includes an inner rotor 72 that rotates using the output rotation of the speed reducer B, an outer rotor 73 that rotates following the rotation of the inner rotor 72, and a pump The cycloid pump includes a chamber 74, a suction port 75 communicating with the suction passage 46 of the oil pump, and a discharge port 76 communicating with the discharge passage 48 formed in the casing 22a.

  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 rotated by the output shaft 33 of the speed reducer B via the one-way clutch 60. Specifically, the inner rotor 72 is rotated via the one-way clutch 60 by the pump drive shaft 33 c connected to the output shaft 33.

  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 a pump case 77a provided on the partition wall 22c.

  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 33 of the speed reducer B, the outer rotor 73 rotates in a driven manner. At this time, since the inner rotor 72 and the outer rotor 73 rotate about different rotation centers c1 and c2, respectively, the volume of the pump chamber 74 changes continuously. As a result, the lubricating oil flowing in from the suction port 75 is pumped from the discharge port 76 to the discharge passage 48.

  In the embodiment shown in FIGS. 1 to 3, a one-way clutch 60 is provided between the inner rotor 72 of the oil pump 42 and the pump drive shaft 33 c to block transmission of the pump drive shaft 33 c during reverse running (reverse rotation). ing. When a cycloid pump is used as the oil pump 42, the suction / discharge direction is reversed during reverse travel (reverse rotation), so that the lubricating oil in the oil passage flows backward. The oil pump 42 is not driven during traveling (reverse rotation).

  FIG. 9A shows the power transmission state of the one-way clutch, and FIG. 9B shows the power cutoff state of the one-way clutch.

  The one-way clutch shown in FIGS. 9A and 9B is generally called a roller type, and mainly includes an outer ring 61, a roller 62, a spring 63, and a cage 64. The outer peripheral surface of the outer ring 61 is fitted into the inner peripheral surface of the inner rotor 72 of the oil pump 42, and the outer ring 61 rotates integrally with the inner rotor 72 of the oil pump 42. A predetermined cam surface is formed on the inner peripheral surface of the outer ring 61. An annular gap is provided between the outer peripheral surface of the pump drive shaft 33c and the inner peripheral surface (cam surface) of the outer ring 61, and a plurality of sets of rollers 62 and springs 63 are provided there. These are held by the cage 64. Each spring 63 urges each roller 62 to one side in the circumferential direction.

  When the pump drive shaft 33 c tries to rotate clockwise with respect to the outer ring 61, the roller 62 advances to the meshing position of the inner peripheral surface (cam surface) of the outer ring 61 due to the spring force of the spring 63, and the inner periphery of the outer ring 61. The rotation of the pump drive shaft 33c is transmitted to the outer ring 61 by the wedge action between the surface (cam surface) and the roller 62, and the inner rotor 72 of the oil pump 42 rotates.

  On the other hand, when the pump drive shaft 33c rotates counterclockwise with respect to the outer ring 61, the pump drive shaft 33c rotates relative to the outer ring 61, and the roller 62 rotates on the inner peripheral surface of the outer ring 61 ( The outer ring 61 rotates away from the cam surface), and the rotational force of the pump drive shaft 33c is cut off, and the inner rotor 72 of the oil pump 42 does not rotate.

  As described above, the one-way clutch 60 is switched between ON and OFF depending on the rotation direction of the pump drive shaft 33c, and allows the rotation of the oil pump 42 only in the direction of sucking the lubricating oil from the oil tank 41. As a result, at the time of backing, the rotation of the oil pump 42 is stopped, and it is possible to prevent the lubricating oil in the oil passage from becoming empty.

  In the one-way clutch 60, the cam surface is provided on the inner peripheral surface of the outer ring 61. However, the cam surface is provided on the outer peripheral surface of the pump drive shaft 33c, and the inner peripheral surface of the outer ring 61 is formed on the cylindrical surface. May be. Further, a one-way clutch other than the roller type may be used.

  As shown in FIGS. 2, 3, 6, and 7, the cycloid reduction gear B supports two curved plates 31 rotatably by eccentric shaft portions 30 a and 30 b provided on the input shaft 30. The corrugated tooth profile 31 a formed on the outer periphery of the curved plate 31 is engaged with the outer pin 32 disposed inside the casing 22 b of the speed reducer B (see FIG. 6), and the curved plate is rotated by the rotation of the input shaft 30. The rotation of the curved plate 31 is output from the output shaft 33 arranged coaxially with the input shaft 30 to rotate the wheel hub C.

  The number of outer pins 32 disposed inside the casing 22 b of the reduction gear B is larger than the corrugated tooth profile 31 a on the outer periphery of the curved plate 31.

  As shown in FIG. 6, the outer pin 32 is supported by an outer pin housing 50 that is located on the inner diameter surface of the casing 22 b of the speed reducer B via a gap. The outer pin housing 50 is floatingly supported by floating bolts (not shown) on the outer side and the inner side with respect to the casing 22b of the speed reducer B.

  2 and 3, one end of the input shaft 30 is connected to the motor rotating shaft 24a of the rotor 24 by spline fitting (including serration fitting, the same applies hereinafter), and is driven to rotate by the motor unit A. The other end portions are provided with eccentric shaft portions 30a and 30b.

  As shown in FIG. 6, a pair of eccentric shaft portions 30 a and 30 b are provided in the axial direction of the input shaft 30. The pair of eccentric shaft portions 30a and 30b is provided such that the center of the cylindrical outer diameter surface is 180 degrees out of phase in the circumferential direction, and rolls to the outer diameter surface of each of the pair of eccentric shaft portions 30a and 30b. A bearing 34 is fitted.

  The eccentric shaft portions 30a, 30b are provided with oil holes 45a, 45b, 45c, and the lubricating oil passing through the internal passage 45 of the input shaft 30 scatters from these oil holes 45a, 45b, 45c, Lubricate the sliding surface.

  The input shaft 30 provided with the pair of eccentric shaft portions 30a and 30b is provided with a pair of counterweights 35 with a 180 ° phase shift in the circumferential direction so as to sandwich the pair of eccentric shaft portions 30a and 30b.

  As shown in FIG. 7, the curved plate 31 is rotatably supported on the input shaft 30 by a rolling bearing 34, and the corrugated tooth profile 31a formed on the outer periphery thereof is a trochoidal curved tooth profile. In the curved plate 31, a plurality of pin holes 36 are formed at equal intervals on one circle centered on the rotation axis, and an inner pin 37 is inserted into each of the pair of pin holes 36 arranged in the axial direction with a margin. A part of the outer periphery of the needle roller bearing 37 a rotatably supported by the inner pin 37 is in contact with a part of the inner periphery of the pin hole 36.

  As shown in FIG. 6, the speed reducer B is engaged with two curved plates 31 as revolving members that are rotatably held by the eccentric shaft portions 30 a and 30 b, and a corrugated tooth profile 31 a on the outer peripheral portion of the curved plate 31. A plurality of outer pins 32, an output shaft 33 that outputs the rotation of the curved plate 31, and a gap between the two curved plates 31, abutting against the end surfaces of the curved plates 31 to tilt the curved plate 31. And a center collar 38 to prevent.

  As shown in FIGS. 2 and 3, the output shaft 33 has a flange portion 33a and a shaft portion 33b. Inner pins 37 are fixed to the flange portion 33 a at equal intervals on a circumference centered on the rotation axis of the output shaft 33. As shown in FIG. 3, a wheel hub C is provided on the outer diameter surface of the shaft portion 33b so that torque can be transmitted by serration (or spline). As shown in FIG. 3, the flange portion 33a and the stabilizer 33d are connected via a plurality of inner pins 37, and the output shaft 33 and the stabilizer 33d rotate integrally. A pump drive shaft 33c connected to the inner rotor 72 of the oil pump 42 is provided at the end of the stabilizer 33d on the motor part A side.

  The outer pins 32 are provided at equal intervals on the circumferential track of the rotation axis of the input shaft 30. When the curved plate 31 revolves, the corrugated tooth profile 31a (see FIG. 7) on the outer periphery engages with the outer pin 32 to cause the curved plate 31 to rotate.

  As shown in FIGS. 2 and 3, the inner diameter surface of the flange portion 33 a of the output shaft 33 and the outer diameter surface of the input shaft 30 are supported so as to be relatively rotatable via a rolling bearing 91.

  The curved plate 31 is incorporated between the flange portion 33a and the stabilizer 33d facing the output shaft 33. Further, both ends of the inner pin 37 penetrating the pin hole 36 of the incorporated curved plate 31 are supported by the opposing flange portion 33a and the stabilizer 33d of the output shaft 33.

  As shown in FIG. 6, the plurality of inner pins 37 supported by the flange portion 33 a and the stabilizer 33 d facing the output shaft 33 are provided at equal intervals on a circumferential track centering on the rotation axis of the input shaft 30. In order to reduce the frictional resistance with the curved plate 31, needle roller bearings 37 a are provided at positions where they contact the inner wall surfaces of the pin holes 36 of the two curved plates 31. The inner diameter dimension of the pin hole 36 is set to be larger than the outer diameter dimension of the inner pin 37 (referred to as “maximum outer diameter including the needle roller bearing 37a”; the same applies hereinafter).

  As shown in FIGS. 2 and 3, the wheel hub C includes an inner ring member 81 fitted and connected to the outer diameter surface of the shaft portion 33b of the output shaft 33 in a state where torque can be transmitted by serration (or spline), And an outer ring member 82 that holds the member 81 rotatably with respect to the casing 22b. The inner ring member 81 and the outer ring member 82 constitute a double-row angular ball bearing, and a double-row rolling element 83 is installed between the inner ring member 81 and the outer ring member 82. The inner ring member 81 is integrally provided with a wheel mounting flange portion 84.

  The outer pin 32 is not directly held by the casing 22b, but is held by an outer pin housing 50 supported in a floating state on the inner diameter surface of the casing 22b, as shown in FIGS.

  In the in-wheel motor drive device 21, from the viewpoint of weight reduction, the casing 22 is preferably made of a light metal such as an aluminum alloy or a magnesium alloy, and the outer pin housing 50 that requires high strength is preferably made of steel.

  The cycloid reduction gear B is lubricated by the lubricating oil supplied from the oil pump 42 passing through the internal passage 45 of the input shaft 30 and from the oil holes 45a, 45b, 45c provided in the eccentric shaft portions 30a, 30b. Lubricating oil scattered and splashed and accumulated in the outer pin housing 50 is scraped up by the rotation of the curved plate 31 and becomes splashed to lubricate the rolling surface and sliding surface of each part. Lubricating oil lubricates and cools the motor part A and the reducer B, and then between the discharge port 49 of the casing 22b of the reducer B, and the casing 22b of the reducer B and the casing 22a of the motor part A. The oil is discharged to the oil tank 41 through a communication hole 47 provided in the partition wall 22c.

  As shown in FIGS. 2 and 3, the motor unit A of the in-wheel motor drive device 21 configured as described above receives, for example, an electromagnetic force generated by supplying an alternating current to the coil of the stator 23, and receives a permanent magnet or a magnet. The rotor 24 constituted by the body rotates.

  Thereby, when the motor rotating shaft 24a connected to the rotor 24 rotates, the curved plate 31 revolves around the rotating axis of the motor rotating shaft 24a. At this time, the outer pin 32 is engaged with the curved waveform tooth shape of the curved plate 31 so as to make rolling contact, and the curved plate 31 rotates in the direction opposite to the rotation of the motor rotating shaft 24a.

  The inner pin 37 inserted through the pin hole 36 of the curved plate 31 is sufficiently thinner than the inner diameter of the pin hole 36 and abuts against the inner wall surface of the pin hole 36 as the curved plate 31 rotates. Thereby, the revolution motion of the curved plate 31 is not transmitted to the inner pin 37, and only the rotational motion of the curved plate 31 is transmitted to the wheel hub C via the output shaft 33.

  At this time, the output shaft 33 arranged coaxially with the rotation axis extracts the rotation of the curved plate 31 as the output shaft of the speed reducer B, and the rotation of the motor rotating shaft 24a is decelerated by the speed reducer B and transmitted to the output shaft 33. Therefore, even when the low torque, high rotation type motor unit A is employed, it is possible to transmit the necessary torque to the drive wheels.

  Thus, by adopting the reduction gear B that can obtain a large reduction ratio without using a multi-stage configuration, a compact and high reduction ratio in-wheel motor drive device 21 can be obtained. Further, since the outer pin 32 is rotatable with respect to the outer pin housing 50 and the needle roller bearing 37a is provided at a position where the outer pin 32 contacts the curved plate 31, the frictional resistance is reduced. The transmission efficiency of B is improved.

  In the embodiment described above, two curved plates 31 of the speed reducer B are provided by changing the phase by 180 °. However, the number of curved plates can be arbitrarily set. For example, when three curved plates are provided. May be provided by changing the phase by 120 °.

  In the above-described embodiment, an example of a cylindrical roller bearing has been shown as the rolling bearing 34 that supports the curved plate 31. However, the present invention is not limited to this example. For example, a plain bearing, a deep groove ball bearing, a tapered roller bearing, and a needle roller Bearings, spherical roller bearings, angular contact ball bearings, 4-point contact ball bearings, etc., whether they are plain bearings or rolling bearings, regardless of whether the rolling elements are rollers or balls, All bearings can be applied, whether double row or single row. Similarly, any type of bearing can be adopted for bearings arranged in other locations.

  In the above-described embodiment, a radial gap motor including the stator 23 fixed to the casing 22a and the rotor 24 disposed at a position facing the inner side of the stator 23 with a gap in the radial direction is provided in the motor portion A. Although the adopted example is shown, the present invention is not limited to this, and a motor having an arbitrary configuration can be applied. 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.

  Further, in the above-described embodiment, the oil pump 42 has shown the example in which the inner rotor 72 rotates using the output rotation of the speed reducer B. However, the present invention is not limited to this, and the rotation of the rotor 24 of the motor unit A is not limited thereto. An oil pump in which the inner rotor rotates using the Moreover, although the one-way clutch 60 is shown between the pump rotating shaft 33c and the inner rotor 72, the one-way clutch 60 is not necessarily required.

  In the above-described embodiment, the example in which the present invention is applied to the in-wheel motor system has been described. However, the drive shaft is connected to the output shaft of the speed reducer via a joint, and the rotation of the drive shaft is applied to the hub wheel. The present invention can also be applied to an on-board system that transmits and drives a drive wheel.

  Furthermore, the electric vehicle equipped with the electric vehicle drive device 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.

  Moreover, in each said embodiment, although the example of the in-wheel motor drive device 21 which employ | adopted the cycloid deceleration mechanism as the reduction gear B was shown, it is not restricted to this but arbitrary deceleration mechanisms are employable. For example, a planetary gear reduction mechanism, a parallel shaft gear reduction mechanism, or the like is applicable.

11: Electric vehicle 12: Chassis 12a: Wheel housing 12b: Suspension device 13: Front wheel 14: Drive wheel 14a: Wheel 14b: Tire 14c: Wheel mounting bolt 15: Brake disc 21: In-wheel motor drive device 22: Casing 22a: Casing 22b: casing 22c: partition wall 22d: rear cover 23: stator 24: rotor 24a: motor rotating shaft 25a: bearing 25b: bearing 30: input shaft 30a: eccentric shaft portion 30b: eccentric shaft portion 31: curved plate 31a: corrugated tooth profile 32 : Outer pin 33: Output shaft 33a: Flange portion 33b: Shaft portion 33c: Pump drive shaft 33d: Stabilizer 34: Rolling bearing 35: Counter weight 36: Pin hole 37: Inner pin 37a: Bearing 38: Center collar 41: Oil tank 42: Oil pump 43a: Oil supply passage 43b: Rear cover passage 44: Internal passage 44a: Oil hole 45: Internal passage 45a: Oil hole 45b: Oil hole 45c: Oil hole 46: Suction passage 47: Communication hole 48: Discharge passage 49: Discharge port 50: outer pin housing 60: one-way clutch 61: outer ring 62: roller 63: spring 64: retainer 72: inner rotor 72a: tooth tip portion 72b: tooth groove portion 73: outer rotor 73a: tooth tip portion 73b: tooth groove portion 74: Pump chamber 75: Suction port 76: Discharge port 77a: Pump case 81: Inner ring member 82: Outer ring member 83: Rolling element 84: Wheel mounting flange portion 90: Rolling bearing 91 with seal: Rolling bearing A: Motor portion B: Reducer C: Wheel hub

Claims (6)

A motor unit having a motor rotation shaft that outputs rotation; a speed reducer that decelerates and outputs the rotation of the motor rotation shaft; a casing that houses the motor unit and the speed reducer; and an oil tank provided below the casing; It has an oil pump that sucks lubricating oil from the oil tank by the rotation of the inner rotor, supplies the lubricating oil to the motor unit and the speed reducer, and lubricates and cools the motor unit and the speed reducer. A wheel drive device for driving a wheel,
A casing oil passage extending rearward from the discharge port of the oil pump along the inside of the casing of the motor unit; and an internal passage provided in the motor rotation shaft connected to the casing oil passage. A vehicle characterized in that an inlet side of a casing oil passage connected to the outlet is provided below the horizontal, and an outlet side connected to an internal passage of the motor rotation shaft of the casing oil passage is provided above the horizontal. Drive device.   The vehicle drive device according to claim 1, wherein the casing oil passage is provided below a rotation axis of the inner rotor.   The vehicle drive apparatus according to claim 1, wherein the casing oil passage is disposed on a front side in a traveling direction of the vehicle.   The vehicle drive apparatus according to claim 1, wherein the oil pump is driven by rotation of the motor unit or rotation of a speed reducer.   The vehicle drive device according to claim 4, wherein the oil pump is a cycloid pump.   6. The vehicle drive device according to claim 5, wherein a one-way clutch that transmits rotation only when the rotation shaft rotates in a rotation direction in which the oil pump is driven is provided on the rotation shaft that drives the oil pump.

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