JP2009262616A - Motor driving device and in-wheel motor driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor driving device of high reliability with a structure not transmitting load applied to a wheel, to a motor part. <P>SOLUTION: The motor driving device includes a motor part A rotationally driving a motor side rotating member 25; a speed reducing part B moderating and transmitting the rotation of the motor side rotating member 25 to an output side rotating member 28; and first to third bearings 36a, 36b, 36c supporting the motor side rotating member 25 rotatably. The motor side rotating member 25 includes a hollow motor rotating shaft 24a rotatably supported by the first and second bearings 36a, 36b within the motor part A, and a reduction gear input shaft 24c with its axial one end fittingly fixed to the inside of the motor rotating shaft 24a in the position of the second bearing 36b and with its axial other end rotatably supported by the third bearing 36c within the speed reducing part B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  A conventional in-wheel motor drive device 101 is described in, for example, Japanese Patent Application Laid-Open No. 2006-258289 (Patent Document 1). Referring to FIG. 11, an in-wheel motor drive device 101 includes a motor unit 103 that generates a driving force inside a casing 102 that is attached to a vehicle body, a wheel hub bearing unit 104 that is connected to a wheel, and a motor unit 103. And a speed reduction portion 105 that reduces the rotation and transmits the reduced speed to the wheel hub bearing portion 104.

  In the in-wheel motor drive device 101 having the above configuration, a low torque and high rotation motor is employed for the motor unit 103 from the viewpoint of making the device compact. On the other hand, the wheel hub bearing portion 104 requires a large torque to drive the wheel. Therefore, a cycloid reducer that is compact and can provide a high reduction ratio may be employed as the reduction unit 105.

Moreover, the speed reduction part 105 to which the conventional cycloid reduction gear is applied includes a motor-side rotating member 106 having eccentric parts 106a and 106b, curved plates 107a and 107b disposed on the eccentric parts 106a and 106b, and curved plates 107a and 107b. A rolling bearing 111 that rotatably supports the motor-side rotating member 106, a plurality of outer pins 108 that engage with the outer peripheral surfaces of the curved plates 107a and 107b to cause the curved plates 107a and 107b to rotate. And a plurality of inner pins 109 that transmit the rotational motion of the curved plates 107a and 107b to the wheel-side rotating member 110.
JP 2006-258289 A

  In the in-wheel motor drive device having the above-described configuration, the motor-side rotating member 106 is connected to the rotor at one axial end portion (right side in FIG. 11), and the other axial end portion (left side in FIG. 11). The curved plates 107a and 107b are supported. Therefore, if the motor-side rotating member 106 is tilted by a load acting on the wheels, the distance between the rotor and the stator may change, causing rotation failure of the motor unit 103, or contact with each other and causing damage.

  Accordingly, an object of the present invention is to provide a highly reliable motor drive device and in-wheel motor drive device by adopting a structure that does not transmit a load acting on the wheel to the motor unit.

  The motor drive device according to the present invention includes a motor unit that rotationally drives the motor side rotation member, a speed reduction unit that decelerates the rotation of the motor side rotation member and transmits the rotation to the output side rotation member, and the motor side rotation member is rotatable. And first to third bearings to be supported. The motor-side rotating member includes a hollow motor rotating shaft that is rotatably supported by the first and second bearings in the motor portion, and one end portion in the axial direction of the motor rotating shaft at the position of the second bearing. A speed reducer input shaft that is fitted and fixed to the inside and whose end on the other side in the axial direction is rotatably supported by a third bearing in the speed reducing portion.

  By supporting the fitting position between the motor rotation shaft and the reduction gear input shaft with the second bearing as in the above configuration, it is effective that the moment load acting on the reduction gear input shaft is transmitted to the motor rotation shaft. Can be prevented. As a result, a highly reliable motor drive device can be obtained.

  Preferably, a radial gap is formed between the inner diameter surface of the motor rotation shaft and the outer diameter surface of the reduction gear input shaft on the speed reduction portion side from the position of the second bearing. Thereby, even if the speed reducer input shaft is inclined to some extent, the influence on the motor rotation shaft can be minimized.

  As one embodiment, the first to third bearings are ball bearings. As another embodiment, the first to third bearings are cylindrical roller bearings having cylindrical rollers having a raceway surface subjected to crowning. By adopting such a bearing, axial misalignment of the three bearings can be absorbed.

  Preferably, the motor side rotation member has an eccentric part. The speed reducing portion has a through hole that passes through the eccentric portion, and is fixed to the casing and the revolving member that performs the revolving motion around the rotation axis as the motor side rotating member rotates. An outer peripheral engagement member that engages with the outer peripheral portion to cause rotation of the revolving member, an inner pin provided on the wheel-side rotating member, and a revolving member are formed on the outer diameter of the inner pin by a predetermined amount. And a motion conversion mechanism that has a hole for receiving the inner pin and converts the rotational motion of the revolving member into a rotational motion around the rotational axis of the motor-side rotating member and transmits it to the wheel-side rotating member. By adopting a so-called cycloid reducer having the above-described configuration, a compact and high reduction ratio can be obtained.

  An in-wheel motor drive device according to the present invention includes any of the motor drive devices described above and a wheel hub fixedly connected to a wheel-side rotation member as an output-side rotation member.

  According to the present invention, it is effective that the moment load acting on the speed reducer input shaft is transmitted to the motor rotating shaft by supporting the fitting position between the motor rotating shaft and the speed reducer input shaft by the second bearing. Can be prevented. As a result, a highly reliable motor drive device and in-wheel motor drive device can be obtained.

  With reference to FIGS. 1-10, the in-wheel motor drive device 21 which concerns on one Embodiment of this invention is demonstrated.

  FIG. 9 is a schematic view of an electric vehicle 11 employing an in-wheel motor drive device 21 according to an embodiment of the present invention, and FIG. 10 is a schematic view of the electric vehicle 11 as viewed from the rear. Referring to FIG. 9, an electric vehicle 11 includes an in-wheel motor drive device that transmits driving force to a chassis 12, front wheels 13 as steering wheels, rear wheels 14 as drive wheels, and left and right rear wheels 14. 21. Referring to FIG. 10, the rear wheel 14 is housed inside a wheel housing 12 a of the chassis 12, and is fixed to the lower portion of the chassis 12 via a suspension device (suspension) 12 b.

  The suspension device 12b supports the rear wheel 14 by a suspension arm extending to the left and right, and suppresses vibration of the chassis 12 by absorbing vibration received by the rear 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 is provided at the 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 for driving the left and right rear 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.

  On the other hand, in order to improve the running stability of the electric vehicle 11, it is necessary to suppress the unsprung weight. In addition, in-wheel motor drive device 21 is required to be downsized in order to secure a wider cabin space. Therefore, an in-wheel motor drive device 21 according to an embodiment of the present invention as shown in FIG. 1 is employed.

  With reference to FIGS. 1-8, the in-wheel motor drive device 21 which concerns on one Embodiment of this invention is demonstrated. 1 is a schematic cross-sectional view of the in-wheel motor drive device 21, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, FIG. 3 is an enlarged view around the eccentric portions 25a and 25b, and FIG. FIG. 5 is a sectional view taken along line V-V in FIG. 1, FIG. 6 is a sectional view taken along line VI-VI in FIG. 1, and FIG. 7 is taken along line VII-VII in FIG. FIG. 8 is a sectional view of the rotary pump 51.

  First, referring to FIG. 1, an in-wheel motor drive device 21 as an example of a vehicle deceleration unit includes a motor unit A that generates a driving force, a deceleration unit B that decelerates and outputs the rotation of the motor unit A, A wheel hub bearing portion C for transmitting the output from the speed reduction portion B to the drive wheel 14 is provided. The motor portion A and the speed reduction portion B are accommodated in the casing 22 and, as shown in FIG. Installed inside.

  The motor part A includes a stator 23a fixed to the casing 22, a rotor 23b disposed at a position facing the inner side of the stator 23a with a radial gap, and a rotor 23b fixedly connected to the inner side of the rotor 23b. It is a radial gap motor provided with the motor side rotation member 25 which rotates integrally.

  The motor side rotation member 25 is disposed from the motor part A to the speed reduction part B in order to transmit the driving force of the motor part A to the speed reduction part B, and is rotatably supported by the first to third bearings 36a, 36b, 36c. Has been. More specifically, the motor-side rotation member 25 includes a hollow motor rotation shaft 24a and a reduction gear input shaft 24b.

  The motor rotating shaft 24a is fitted and fixed to the inner diameter surface of the rotor 23b to rotate integrally, and the motor portion A has one axial end (right side in FIG. 1) as the first bearing 36a in the axial direction. The other end (left side in FIG. 1) is rotatably supported by the second bearing 36b.

  The speed reducer input shaft 24b has one axial end (right side in FIG. 1) fitted into the inner diameter surface of the motor rotating shaft 24a, and the other axial end (left side in FIG. 1) is the speed reducing portion. B is rotatably supported by the third bearing 36c with respect to the output side rotation member 28. Further, the speed reducer input shaft 24b has eccentric portions 25a and 25b in the speed reduction portion B. Further, the two eccentric portions 25a and 25b are provided with a 180 ° phase change in order to cancel the centrifugal force due to the eccentric motion.

  Referring to FIG. 4, motor rotation shaft 24a and reduction gear input shaft 24b are fitted and fixed on the position of second bearing 36b and on motor portion A side (right side in FIG. 1) from second bearing 36b. Has been. In this embodiment, both are fitted and fixed by serration fitting. Thus, by supporting the fitting position between the motor rotation shaft 24a and the reduction gear input shaft 24b by the second bearing 36b, the moment load acting on the reduction gear input shaft 24b is transmitted to the motor rotation shaft 24a. Can be effectively prevented.

  Further, on the speed reduction part B side (left side in FIG. 1) from the position of the second bearing 36b, a radial clearance 24c is formed between the inner diameter surface of the motor rotation shaft 24a and the outer diameter surface of the reduction gear input shaft 24b. Is formed. Thereby, even if the speed reducer input shaft 24b is inclined to some extent, the influence on the motor rotation shaft 24a can be minimized.

  Further, the bearings directly supporting the motor rotating shaft 24a are the first and second bearings 36a and 36b, both of which are arranged in the motor portion A. On the other hand, the third bearing 36c is the only bearing that directly supports the speed reducer input shaft 24b, and is disposed in the speed reducing portion B. That is, the motor part A and the speed reduction part B can be assembled independently, and finally, if the motor rotation shaft 24a and the speed reducer input shaft 24b are serrated and fitted, the motor drive device according to the present invention can be obtained. Can do.

  In addition, although the kind of 1st-3rd bearing 36a, 36b, 36c is not ask | required, it is desirable to employ | adopt a ball bearing as shown in FIG. Thereby, the axial misalignment of the three bearings (referring to “the bearing centers of the three bearings being displaced”) can be allowed. Alternatively, the same effect can be expected even when a cylindrical roller bearing having a cylindrical roller with a crowned surface is used.

  The deceleration part B is held at a fixed position on the casing 22 and curved plates 26a and 26b as revolving members that are rotatably held by the eccentric parts 25a and 25b, and engages with the outer peripheral parts of the curved plates 26a and 26b. A plurality of outer pins 27 as outer peripheral engagement members, a motion conversion mechanism for transmitting the rotational motion of the curved plates 26a, 26b to the wheel side rotation member 28, and a counterweight 29 at a position adjacent to the eccentric portions 25a, 25b. Prepare. In addition, the speed reduction part B is provided with a speed reduction part lubrication mechanism that supplies lubricating oil to the speed reduction part B.

  The wheel side rotation member 28 includes a flange portion 28a and a shaft portion 28b. Holes for fixing the inner pins 31 are formed on the end face of the flange portion 28a at equal intervals on the circumference around the rotation axis of the wheel side rotation member 28. Further, the shaft portion 28 b is fitted and fixed to the wheel hub 32 and transmits the output of the speed reduction portion B to the wheel 14.

  2 and 3, the curved plate 26a has a plurality of corrugations composed of trochoidal curves such as epitrochoids on the outer periphery, and a plurality of through holes penetrating from one end face to the other end face. 30a and 30b. A plurality of through holes 30a are provided at equal intervals on the circumference centered on the rotation axis of the curved plate 26a, and receive an inner pin 31 described later. Further, the through hole 30b is provided at the center of the curved plate 26a and is fitted to the eccentric portion 25a.

  The curved plate 26a is rotatably supported by the rolling bearing 41 with respect to the eccentric portion 25a. Referring to FIG. 3, this rolling bearing 41 is fitted to the outer diameter surface of the eccentric portion 25a, and the inner ring member 42 having an inner raceway surface 42a on the outer diameter surface, and the inner diameter of the through hole 30b of the curved plate 26a. The outer raceway surface 43 formed directly on the surface, a plurality of cylindrical rollers 44 disposed between the inner raceway surface 42a and the outer raceway surface 43, and a retainer (not shown) that keeps an interval between the adjacent cylindrical rollers 44 It is a cylindrical roller bearing provided with. Further, the inner ring member 42 has flange portions 42b that protrude radially outward from both axial end portions of the inner raceway surface 42a.

  The outer pins 27 are provided at equal intervals on a circumferential track centering on the rotation axis of the motor side rotation member 25. When the curved plates 26a and 26b revolve, the curved waveform and the outer pin 27 are engaged to cause the curved plates 26a and 26b to rotate. Here, the outer pin 27 is rotatably supported with respect to the casing 22 by a needle roller bearing 27a. Thereby, the contact resistance between the curved plates 26a and 26b can be reduced.

  The counterweight 29 has a disc shape and has a through-hole that fits with the motor-side rotation member 25 at a position off the center, in order to counteract the unbalanced inertia couple generated by the rotation of the curved plates 26a and 26b. It is arranged at a position adjacent to each eccentric part 25a, 25b with a 180 ° phase change from the eccentric part.

Here, referring to FIG. 3, if the center point between the two curved plates 26a, 26b is G, the distance between the central point G and the center of the curved plate 26a is the right side of the central point G in FIG. The sum of masses of L ₁ , the curved plate 26 a, the rolling bearing 41, and the eccentric portion 25 a is m ₁ , and the eccentric amount of the center of gravity of the curved plate 26 a from the rotational axis is ε ₁ . L ₁ × m ₁ × ε ₁ = L ₂ × m ₂ × ε ₂ , where L _{2 is} the distance, m _{2 is} the weight of the counterweight 29, and ε ₂ is the amount of eccentricity of the center of gravity of the counterweight 29 from the rotational axis. It is a relationship that satisfies A similar relationship is also established between the curved plate 26b on the left side of the center point G in FIG.

  The motion conversion mechanism includes a plurality of inner pins 31 held by the wheel-side rotating member 28 and through holes 30a provided in the curved plates 26a and 26b. The inner pins 31 are provided at equal intervals on a circumferential track centering on the rotational axis of the wheel side rotation member 28, and one axial end thereof is fixed to the wheel side rotation member 28. Further, in order to reduce the frictional resistance with the curved plates 26a, 26b, needle roller bearings 31a are provided at positions where they contact the inner wall surfaces of the through holes 30a of the curved plates 26a, 26b.

  A stabilizer 31b is provided at the axial end of the inner pin 31. The stabilizer 31b includes an annular ring portion 31c and a cylindrical portion 31d extending in the axial direction from the inner diameter surface of the annular portion 31c. The other axial side other ends of the plurality of inner pins 31 are fastened to the annular portion 31c by bolts. Since the load applied to some of the inner pins 31 from the curved plates 26a and 26b is supported by all the inner pins 31 via the stabilizer 31b, the stress acting on the inner pins 31 is reduced and the durability is improved. Can do.

  On the other hand, the through hole 30a is provided at a position corresponding to each of the plurality of inner pins 31, and the inner diameter of the through hole 30a is the outer diameter of the inner pin 31 ("the maximum outer diameter including the needle roller bearing 31a"). The same shall apply hereinafter).

  The speed reduction unit lubrication mechanism supplies lubricating oil to the speed reduction unit B, and includes a lubricating oil passage 25c, a lubricating oil supply port 25d, a lubricating oil discharge port 22b, a lubricating oil storage unit 22d, and a rotary pump 51. And a circulating oil passage 45.

  The lubricating oil passage 25c extends along the axial direction inside the motor-side rotating member 25. The lubricating oil supply port 25d extends from the lubricating oil passage 25c toward the outer diameter surface of the motor-side rotating member 25. In this embodiment, the lubricating oil supply port 25d is provided in the eccentric portions 25a and 25b.

  Further, at least one location of the casing 22 at the position of the speed reduction portion B is provided with a lubricating oil discharge port 22b for discharging the lubricating oil inside the speed reduction portion B. A circulating oil passage 45 that connects the lubricating oil discharge port 22 b and the lubricating oil passage 25 c is provided inside the casing 22. Then, the lubricating oil discharged from the lubricating oil discharge port 22 b returns to the lubricating oil path 25 c via the circulating oil path 45.

  The circulating oil passage 45 is connected to the oil passages 46 a to 46 y (generically referred to as “axial oil passage 46”) extending in the axial direction inside the casing 22 and to both ends of the axial oil passage 46 in the axial direction. Oil passages 47a to 47f (generally referred to as “circumferential oil passage 47”) extending in the circumferential direction and oil passages 48a, 48b (collectively “diameter”) connected to the circumferential oil passages 47a and 47f and extending in the radial direction. Directional oil passage 48 ").

  The axial oil passage 46 includes first axial oil passages 46a to 46e, 46k to 46o, 46u to 46y through which lubricating oil flows in one direction (from left to right in FIG. 1), and lubricating oil in the other direction (see FIG. 1 are classified into second axial oil passages 46f to 46j and 46p to 46t that flow from right to left in FIG. That is, the circulating oil passage 45 reciprocates in the axial direction inside the casing 22.

  The circumferential oil passage 47 connects the axial oil passages 46 or the axial oil passage 46 and the radial oil passage 48. Specifically, the circumferential oil passage 47a distributes the lubricating oil flowing out from the radial oil passage 48a to the axial oil passages 46a to 46e. Similarly, the circumferential oil passage 47b passes the lubricating oil flowing out from the axial oil passages 46a to 46e to the axial oil passages 46f to 46j, and the circumferential oil passage 47c receives the lubricating oil flowing out from the axial oil passages 46f to 46j. The axial oil passages 46k to 46o, the circumferential oil passage 47d is the lubricating oil that has flowed out of the axial oil passages 46k to 46o, and the circumferential oil passage 47e is the axial oil passages 46p to 46t. The lubricating oil that has flowed out of the oil is distributed to the axial oil passages 46u to 46y. Further, the circumferential oil passage 47f supplies the lubricating oil flowing out from the axial oil passages 46u to 46y to the radial oil passage 48b.

  The radial oil passage 48a supplies the lubricating oil pumped from the rotary pump 51 to the circumferential oil passage 47a, and the radial oil passage 48b supplies the lubricating oil flowing out from the circumferential oil passage 47f to the circulation oil passage 25c.

  Here, a rotary pump 51 is provided between the lubricating oil discharge port 22b and the circulating oil passage 45, forcibly circulating the lubricating oil. Referring to FIG. 8, rotary pump 51 includes an inner rotor 52 that rotates using the rotation of wheel-side rotating member 28, an outer rotor 53 that rotates following rotation of inner rotor 52, and a pump chamber 54. The cycloid pump includes a suction port 55 communicating with the lubricating oil discharge port 22b and a discharge port 56 communicating with the circulating oil passage 22c.

  Inner rotor 52 has a tooth profile formed of a cycloid curve on the outer diameter surface. Specifically, the shape of the tooth tip portion 52a is an epicycloid curve, and the shape of the tooth gap portion 52b is a hypocycloid curve. The inner rotor 52 is fitted to the outer diameter surface of the cylindrical portion 31d of the stabilizer 31b and rotates integrally with the inner pin 31 (wheel-side rotating member 28).

The outer rotor 53 has a tooth profile constituted by a cycloid curve on the inner diameter surface. Specifically, the shape of the tooth tip portion 53a is a hypocycloid curve, and the shape of the tooth gap portion 53b is an epicycloid curve. The outer rotor 53 is rotatably supported by the casing 22.

The inner rotor 52 is rotated about the rotation center _{c 1.} On the other hand, the outer rotor 53 rotates around a rotation center c ₂ which is different from the rotation center c ₁ of the inner rotor. Further, when the number of teeth of the inner rotor 52 is n, the number of teeth of the outer rotor 53 is (n + 1). In this embodiment, n = 5.

A plurality of pump chambers 54 are provided in the space between the inner rotor 52 and the outer rotor 53. When the inner rotor 52 rotates using the rotation of the wheel side rotation member 28, the outer rotor 53 rotates in a driven manner. At this time, since the inner rotor 52 and the outer rotor 53 rotate around different rotation centers c ₁ and c ₂ , the volume of the pump chamber 54 changes continuously. As a result, the lubricating oil flowing in from the suction port 55 is pumped from the discharge port 56 to the radial oil passage 48a.

  If the inner rotor 52 is tilted during the rotation of the rotary pump 51 configured as described above, the volume of the pump chamber 54 changes and the lubricating oil cannot be properly pumped, or the inner rotor 52 and the outer rotor 53 are There is a risk of contact and damage. Therefore, referring to FIG. 1, the inner rotor 52 is provided with a stepped portion 52 c. The stepped portion 52 c has an outer diameter surface (guide surface) that abuts against the inner diameter surface of the casing 22, and prevents the inner rotor 52 from being inclined by a radial load from the wheel 14.

  Furthermore, between the lubricating oil discharge port 22b and the rotary pump 51, there is provided a lubricating oil reservoir 22d that temporarily stores the lubricating oil. Thereby, at the time of high speed rotation, the lubricating oil that cannot be discharged by the rotary pump 51 can be temporarily stored in the lubricating oil storage section 22d. As a result, an increase in torque loss of the deceleration unit B can be prevented. On the other hand, at the time of low speed rotation, the lubricating oil stored in the lubricating oil reservoir 22d can be returned to the lubricating oil passage 25c even if the amount of lubricating oil reaching the lubricating oil discharge port 22b decreases. As a result, the lubricating oil can be stably supplied to the deceleration unit B.

  In addition, the lubricating oil inside the deceleration part B moves outside by gravity in addition to the centrifugal force. Therefore, it is desirable to attach to the electric vehicle 11 so that the lubricating oil reservoir 22d is positioned below the in-wheel motor drive device 21.

  Further, the speed reduction unit lubrication mechanism further includes cooling means for cooling the lubricating oil passing through the circulating oil passage 45. The cooling means in this embodiment includes a cooling water channel 22e provided in the casing 22 and an air vent plug 22f for discharging air in the cooling water channel 22e. These cooling means contribute not only to the lubricating oil but also to the cooling of the motor part A.

  The cooling water passage 22 e is provided at a position in contact with the radial oil passage 46 inside the casing 22. And the partition member 49 which isolate | separates both is arrange | positioned between the radial direction oil path 46 and the cooling water path 22e. The partition member 49 is a cylindrical member, and is formed of a material having a higher thermal conductivity than the material constituting the casing 22. Specifically, brass, copper, aluminum and the like are applicable. The air vent plug 22f discharges the air contained in the cooling water passage 22e to the outside. Thereby, there is no air accumulation in the cooling water channel 22e, and the cooling efficiency is improved.

  The flow of the lubricating oil in the deceleration portion B having the above configuration will be described. First, the lubricating oil flowing through the lubricating oil passage 25c flows out from the opening 42c penetrating the lubricating oil supply port 25d and the inner ring member 42 to the speed reduction unit B due to the centrifugal force accompanying the rotation of the motor-side rotating member 25.

  Since centrifugal force further acts on the lubricating oil inside the speed reduction portion B, the inner raceway surface 42a, the outer raceway surface 43, the contact portion between the curved plates 26a, 26b and the inner pin 31, and the curved plates 26a, 26b and the outer It moves outward in the radial direction while lubricating the contact portion with the pin 27 and the like.

  The lubricating oil that has reached the inner wall surface of the casing 22 is discharged from the lubricating oil discharge port 22b and stored in the lubricating oil storage portion 22d. The lubricating oil stored in the lubricating oil storage part 22d passes through the flow path in the casing 22 and is supplied from the suction port 55 to the rotary pump 51 and is pumped from the discharge port 56 to the circulation oil path 45.

  The lubricating oil discharged from the discharge port 56 is distributed to the plurality of axial oil passages 46a to 46e through the radial oil passage 48a through the radial oil passage 48a. Next, the lubricating oil that has passed through the axial oil passages 46a to 46e (from left to right in FIG. 1) is distributed to the plurality of axial oil passages 46f to 46j by the circumferential oil passage 47b. Similarly, axial oil passages 46f to 46j (from right to left in FIG. 1), circumferential oil passage 47c, axial oil passages 46k to 46o (from left to right in FIG. 1), circumferential oil passage 47d, shaft Directional oil passages 46p to 46t (right to left in FIG. 1), circumferential oil passage 47e, axial oil passages 46u to 46y (left to right in FIG. 1), circumferential oil passage 47f, and radial oil passage It returns to the lubricating oil passage 25c via 48b.

  Here, the amount of lubricating oil discharged from the lubricating oil discharge port 22 b increases in proportion to the rotational speed of the motor-side rotating member 25. On the other hand, since the inner rotor 52 rotates integrally with the wheel side rotation member 28, the discharge amount of the rotary pump 51 increases in proportion to the rotation speed of the wheel side rotation member 28. In addition, the amount of lubricating oil supplied from the lubricating oil discharge port 22 b to the speed reduction unit B increases in proportion to the discharged amount of the rotary pump 51. That is, since both the supply amount and the discharge amount of the lubricating oil to the speed reduction unit B change depending on the rotational speed of the in-wheel motor drive device 21, the lubricating oil can be circulated smoothly and constantly.

  Further, a part of the lubricating oil flowing through the circulating oil passage 45 lubricates the rolling bearing 36 a from between the casing 22 and the motor-side rotating member 25 and also functions as a cooling liquid for cooling the motor portion A. Further, the rolling bearing 36 b is lubricated by lubricating oil from between the stepped portion 52 c of the rotary pump 51 and the casing 22.

  In this way, by supplying the lubricating oil from the motor side rotating member 25 to the speed reduction unit B, the shortage of the lubricating oil amount around the motor side rotating member 25 can be solved. Further, by forcibly discharging the lubricating oil by the rotary pump 51, it is possible to suppress the stirring resistance and reduce the torque loss of the speed reduction unit B. Furthermore, by arranging the rotary pump 51 in the casing 22, it is possible to prevent the in-wheel motor drive device 21 from being enlarged as a whole.

  Further, by providing the circulating oil passage 45 that reciprocates in the axial direction inside the casing 22 (2.5 reciprocations in this embodiment), the chance of contacting the cooling water passage 22e increases. As a result, the lubricating oil can be sufficiently cooled and then returned to the radial oil passage 48b. Note that the number of reciprocations of the circulating oil passage 45 (2.5 reciprocations) and the number of the axial oil passages 46 (25) can be arbitrarily set. Moreover, not only water but all the cooling liquids can be flowed into the cooling water channel 22e.

  The wheel hub bearing portion C includes a wheel hub 32 fixedly connected to the wheel-side rotating member 28 and a wheel hub bearing 33 that holds the wheel hub 32 rotatably with respect to the casing 22. The wheel hub 32 has a cylindrical hollow portion 32a and a flange portion 32b. The drive wheel 14 is fixedly connected to the flange portion 32b by a bolt 32c. A spline and a male screw are formed on the outer diameter surface of the shaft portion 28b of the wheel side rotation member 28. A spline hole is formed in the inner diameter surface of the hollow portion 32 a of the wheel hub 32. Then, the wheel-side rotating member 28 is screwed onto the inner diameter surface of the wheel hub 32, and both ends are fastened by fastening the tip with a nut 32d.

  The wheel hub bearing 33 is disposed between an inner ring 33a fitted and fixed to the outer diameter surface of the wheel hub 32, an outer ring 33b fitted and fixed to the inner diameter surface of the casing 22, and the inner ring 33a and the outer ring 33b. This is a double-row angular contact ball bearing including a plurality of balls 33c as a moving body, a retainer 33d that holds an interval between adjacent balls 33c, and a sealing member 33e that seals both axial ends of the wheel hub bearing 33.

  Furthermore, a terminal box 61 as a second casing is attached to a position adjacent to the motor part A in the axial direction (on the side opposite to the speed reduction part B). The terminal box 61 includes a power line (not shown) for supplying electric power to the motor part A, a communication hole (not shown) communicating with the inside of the casing 22, and an internal pressure adjusting means on a wall surface facing the radial direction. .

  The power line has one end connected to the coil of the stator 23a and the other end connected to a power source via an inverter, and applies a voltage of a predetermined frequency to the stator 23a in order to rotate the motor part A. The communication hole allows the power line to pass through the casing 22 and allows the lubricating oil and air to move between the casing 22 and the terminal box 61. The internal pressure adjusting means includes an oil supply port (not shown) provided on a wall surface facing the radial direction of the terminal box 61 and an air breather 66 detachably inserted into the oil supply port.

  By providing the internal pressure adjusting means in the terminal box 61 adjacent to the casing 22 as described above, the internal pressure of the casing 22 can be kept constant, and the internal pressure adjusting means is directly provided in the casing 22 including the rotating member. Compared to the case, the leakage of lubricating oil can be suppressed. In order to facilitate the refueling operation, it is desirable that the refueling port is attached to the electric vehicle 11 so that the refueling port is located above the in-wheel motor drive device 21.

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

  The motor unit A receives, for example, electromagnetic force generated by supplying an alternating current to the coil of the stator 23a, and the rotor 23b made of a permanent magnet or a magnetic material rotates. As a result, when the motor-side rotating member 25 connected to the rotor 23b rotates, the curved plates 26a and 26b revolve around the rotation axis of the motor-side rotating member 25. At this time, the outer pin 27 engages with the curved waveform of the curved plates 26 a and 26 b to cause the curved plates 26 a and 26 b to rotate in the direction opposite to the rotation of the motor-side rotating member 25.

  The inner pin 31 inserted through the through hole 30a comes into contact with the inner wall surface of the through hole 30a as the curved plates 26a and 26b rotate. As a result, the revolving motion of the curved plates 26 a and 26 b is not transmitted to the inner pin 31, but only the rotational motion of the curved plates 26 a and 26 b is transmitted to the wheel hub bearing portion C via the wheel-side rotating member 28.

  At this time, since the rotation of the motor-side rotating member 25 is decelerated by the speed reducing portion B and transmitted to the wheel-side rotating member 28, it is necessary for the drive wheel 14 even when the low torque, high rotation type motor portion A is adopted. It is possible to transmit an appropriate torque.

Note that the reduction ratio of the speed reduction unit B having the above-described configuration is calculated as (Z _A −Z _B ) / Z _B where Z _{A is} the number of outer pins 27 and Z _B is the number of waveforms of the curved plates 26a and 26b. The In the embodiment shown in FIG. 2, since Z _A = 12 and Z _B = 11, the reduction ratio is 1/11, and a very large reduction ratio can be obtained.

  In this way, by adopting the speed reduction unit B that can obtain a large speed reduction ratio without using a multi-stage configuration, the in-wheel motor drive device 21 having a compact and high speed reduction ratio can be obtained. Further, by providing the needle roller bearings 27a and 31a on the outer pin 27 and the inner pin 31, the frictional resistance between the curved plates 26a and 26b is reduced, so that the transmission efficiency of the speed reduction part B is improved.

  By employing the in-wheel motor drive device 21 according to the above embodiment in the electric vehicle 11, the unsprung weight can be suppressed. As a result, the electric vehicle 11 having excellent running stability can be obtained.

  Further, in the above-described embodiment, the example in which the lubricating oil supply port 25d is provided in the eccentric portions 25a and 25b is shown, but the present invention is not limited to this, and the lubricating oil supply port 25d can be provided at an arbitrary position. However, from the viewpoint of stably supplying the lubricating oil to the rolling bearing 41, the lubricating oil supply port 25d is preferably provided in the eccentric portions 25a and 25b.

  In the above-described embodiment, the example in which the rotary pump 51 is driven by using the rotation of the wheel-side rotary member 28 is shown. However, the rotary pump 51 is driven by using the rotation of the motor-side rotary member 25. You can also. However, since the rotation speed of the motor side rotation member 25 is larger than that of the wheel side rotation member 28 (11 times in the above embodiment), the durability of the rotary pump 51 may be reduced. Further, even when connected to the wheel-side rotating member 28, a sufficient discharge amount can be ensured. From these viewpoints, the rotary pump 51 is preferably driven by utilizing the rotation of the wheel-side rotary member 28.

  Moreover, in said embodiment, although the example of the cycloid pump was shown as the rotary pump 51, it is not restricted to this, All the rotary pumps driven using the rotation of the wheel side rotation member 28 are employable. it can. Furthermore, the rotary pump 51 may be omitted, and the lubricating oil may be circulated only by centrifugal force.

  Further, in the above embodiment, two curved plates 26a and 26b of the deceleration unit B are provided with 180 ° phase shifts. However, the number of the curved plates can be arbitrarily set. When three are provided, it is preferable to change the phase by 120 °.

  Moreover, although the motion conversion mechanism in said embodiment showed the example comprised by the inner pin 31 fixed to the wheel side rotation member 28, and the through-hole 30a provided in the curve boards 26a and 26b, Without being limited to the above, it is possible to adopt an arbitrary configuration capable of transmitting the rotation of the speed reduction unit B to the wheel hub 32. For example, it may be a motion conversion mechanism composed of an inner pin fixed to a curved plate and a hole formed in the wheel side rotation member.

  In addition, although description of the action | operation in said embodiment was performed paying attention to rotation of each member, the motive power containing a torque is actually transmitted from the motor part A to a driving wheel. Therefore, the power decelerated as described above is converted into high torque.

  Further, in the description of the operation in the above embodiment, power is supplied to the motor unit A to drive the motor unit A, and the power from the motor unit A is transmitted to the drive wheels 14, but on the contrary, When the vehicle decelerates or goes down a hill, the power from the drive wheel 14 side is converted into high-rotation and low-torque rotation by the deceleration unit B and transmitted to the motor unit A, and the motor unit A generates power. May be. Furthermore, the electric power generated here may be stored in a battery and used later for driving the motor unit A or for operating other electric devices provided in the vehicle.

  Further, a brake can be added to the configuration of the above embodiment. For example, in the configuration of FIG. 1, the casing 22 is extended in the axial direction to form a space on the right side of the rotor 23 b in the drawing, a rotating member that rotates integrally with the rotor 23 b, and the casing 22 is not rotatable and axially A parking brake that locks the rotor 23b by disposing a movable piston and a cylinder that operates the piston and fitting the piston and the rotating member when the vehicle is stopped may be used.

  Alternatively, it may be a disc brake that sandwiches a flange formed on a part of a rotating member that rotates integrally with the rotor 23b and a friction plate installed on the casing 22 side with a cylinder installed on the casing 22 side. Furthermore, a drum brake can be used in which a drum is formed on a part of the rotating member, a brake shoe is fixed to the casing 22 side, and the rotating member is locked by friction engagement and self-engagement.

  In the above embodiment, an example of a cylindrical roller bearing is shown as a bearing for supporting the curved plates 26a and 26b. However, the present invention is not limited to this, and for example, a plain bearing, a cylindrical roller bearing, a tapered roller bearing, and a needle roller Regardless of whether it is a plain bearing or a rolling bearing, such as a bearing, a self-aligning roller bearing, a deep groove ball bearing, an angular contact ball bearing, or a four-point contact ball bearing, whether the rolling element is a roller or a ball Furthermore, any bearing can be applied regardless of whether it is a double row or a single row. Similarly, any type of bearing can be adopted for bearings arranged in other locations.

  However, the deep groove ball bearing has a higher allowable limit speed than the cylindrical roller bearing, but has a low load capacity. Therefore, in order to obtain a necessary load capacity, a large deep groove ball bearing must be employed. Therefore, from the viewpoint of making the in-wheel motor drive device 21 compact, a cylindrical roller bearing is suitable for the rolling bearing 41.

  In each of the above-described embodiments, an example in which a radial gap motor is adopted as the motor unit A has been described. For example, it may be an axial gap motor including a stator fixed to the casing and a rotor disposed at a position facing the inner side of the stator with an axial gap.

  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 deceleration part B was shown, it is not restricted to this, Arbitrary deceleration mechanisms can be employ | adopted. For example, a planetary gear reduction mechanism, a parallel shaft gear reduction mechanism, or the like is applicable.

  Furthermore, although the electric vehicle 11 shown in FIG. 9 has shown the example which used the rear wheel 14 as the driving wheel, it is not restricted to this, The front wheel 13 may be used as a driving wheel and may be 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 should be understood as including, for example, a hybrid vehicle.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

It is a figure which shows the in-wheel motor drive device which concerns on one Embodiment of this invention. It is sectional drawing in II-II of FIG. It is an enlarged view of the eccentric part periphery of FIG. It is an enlarged view of the fitting part of the motor rotating shaft of FIG. 1, and a reduction gear input shaft. It is sectional drawing in VV of FIG. It is sectional drawing in VI-VI of FIG. It is sectional drawing in VII-VII of FIG. It is sectional drawing of the rotary pump of FIG. It is a top view of the electric vehicle which has the in-wheel motor drive device of FIG. FIG. 10 is a rear sectional view of the electric vehicle of FIG. 9. It is a figure which shows the conventional in-wheel motor drive device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Electric vehicle, 12 Chassis, 12a Wheel housing, 12b Suspension device, 13 Front wheel, 14 Rear wheel, 21,101 In-wheel motor drive device, 22,102 Casing, 22a Outer member, 22b Lubricating oil discharge port, 22d Lubricating oil Reservoir, 22e Cooling channel, 22f Air vent plug, 23a Stator, 23b Rotor, 24a Motor rotation shaft, 24b Reducer input shaft, 24c Radial clearance, 28a, 32b Flange, 32a Hollow portion, 28b Shaft, 25, 106 Motor side rotating member, 25a, 25b, 106a, 106b Eccentric part, 25c Lubricating oil passage, 25d Lubricating oil supply port, 26a, 26b, 107a, 107b Curved plate, 27, 108 Outer pin, 27a, 31a Needle roller bearing, 28,110 Wheel side rotating member, 29 count Weight, 30a, 30b Through-hole, 31, 109 Inner pin, 31b Stabilizer, 31c Ring part, 31d Cylindrical part, 32 Wheel hub, 32d Nut, 33 Wheel hub bearing, 33a Inner ring, 33b Outer ring, 33c Ball, 33d Cage 33e sealing member, 42a inner raceway surface, 42b flange, 42c opening, 43 outer raceway surface, 36a, 36b, 36c, 41, 111 rolling bearing, 42 inner ring member, 44 cylindrical roller, 45 circulating oil passage, 46a- 46y axial oil passage, 47a to 47f circumferential oil passage, 48a, 48b radial oil passage, 49 partition member, 51 rotary pump, 52 inner rotor, 52a, 53a tooth tip portion, 52b, 53b tooth groove portion, 52c step Attached part, 54 Pump chamber, 55 Suction port, 56 Discharge port, 61 Terminal box, 66 Air Over The.

Claims (6)

A motor unit for rotationally driving the motor side rotating member;
A decelerating portion for decelerating the rotation of the motor side rotating member and transmitting it to the output side rotating member;
Comprising first to third bearings for rotatably supporting the motor side rotating member;
The motor side rotating member is
A hollow motor rotating shaft rotatably supported by the first and second bearings in the motor unit;
One end portion in the axial direction is fitted and fixed inside the motor rotation shaft at the position of the second bearing, and the other end portion in the axial direction is rotatably supported by the third bearing in the speed reduction portion. A motor drive device including a reduction gear input shaft.   The radial clearance is formed between the inner diameter surface of the motor rotation shaft and the outer diameter surface of the speed reducer input shaft on the speed reduction portion side from the position of the second bearing. The motor drive device described.   The motor driving apparatus according to claim 1, wherein the first to third bearings are ball bearings.   3. The motor drive device according to claim 1, wherein the first to third bearings are cylindrical roller bearings having cylindrical rollers having a raceway surface subjected to crowning. 4. The motor side rotating member has an eccentric part,
The deceleration part is
A revolving member having a through-hole through which the eccentric portion is inserted, and performing a revolving motion around the rotation axis as the motor-side rotating member rotates,
An outer periphery engaging member that engages with an outer peripheral portion of the revolving member to cause rotation of the revolving member;
An inner pin provided on the output-side rotating member, and a revolution member formed on the revolving member, and having a hole that is larger than the outer diameter of the inner pin by a predetermined amount to receive the inner pin, and that rotates the revolving member. The motor drive device in any one of Claims 1-4 including the motion conversion mechanism which converts into the rotational motion centering on the rotating shaft center of the said motor side rotating member, and transmits to the said output side rotating member. The motor drive device according to any one of claims 1 to 5,
An in-wheel motor drive device comprising: a wheel hub fixedly connected to a wheel side rotation member as the output side rotation member.

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