JP5079431B2 - In-wheel motor drive device - Google Patents

Description

  The present invention relates 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. 7, 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 101 configured as described above, lubricating oil is sealed inside the speed reduction unit 105, and the contact portions between the curved plates 107 a and 107 b and the outer pins 108 and the inner pins 109 and the raceway surface of the rolling bearing 111. Etc.

  However, the lubricating oil is biased radially outward due to the centrifugal force accompanying the rotation of the motor-side rotating member 106 and the curved plates 107a and 107b, and the amount of lubricating oil around the motor-side rotating member 106 decreases. On the other hand, when the amount of lubricating oil enclosed in the speed reduction unit 105 is increased in order to secure the amount of lubricating oil around the motor-side rotating member 106, torque loss increases as the stirring resistance increases. And this tendency becomes remarkable with the high rotation of the motor side rotation member 106.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an in-wheel motor drive device having excellent durability and high reliability by adopting a structure capable of stably supplying lubricating oil to the entire speed reducing portion.

An in-wheel motor drive device according to the present invention includes a motor unit that rotationally drives a motor-side rotation member, a deceleration unit that decelerates rotation of the motor-side rotation member, and a wheel that transmits rotation reduced by the reduction unit to the wheel side. A side rotation member, a casing that holds the motor unit and the reduction unit, a wheel hub fixedly connected to the wheel side rotation member, and a reduction unit lubrication mechanism that is provided in the casing and supplies lubricating oil to the reduction unit. . The speed reduction part lubrication mechanism is provided in a lubricating oil path provided inside the motor side rotation member, a lubricating oil supply port extending from the lubrication oil path toward the outer diameter surface of the motor side rotation member, and provided in the casing. The lubricating oil discharge port for discharging the lubricating oil, the lubricating oil storage portion for storing the lubricating oil discharged from the lubricating oil discharge port in the casing, and the motor portion and the speed reducing portion in the casing are arranged between the motor portion and the speed reducing portion. Using the decelerated rotation, the rotary pump that sucks and discharges the lubricating oil from the lubricating oil reservoir, and the rotary pump and the lubricating oil passage are connected, and the lubricating oil discharged from the rotary pump is used as the lubricating oil passage. And a circulating oil passage for reflux.

As described above, an oil passage for circulating the lubricating oil is provided, and the lubricating oil is forcibly circulated by the rotary pump, so that the lubricating oil can be stably supplied to the entire speed reduction unit and stirred. An increase in resistance can be prevented. The speed reduction unit lubrication mechanism further includes a lubricating oil reservoir that stores the lubricating oil between the lubricating oil discharge port and the rotary pump. As a result, an increase in the stirring resistance of the speed reduction unit can be prevented, and the lubricating oil can be further stably supplied to the speed reduction unit.

As one embodiment of the speed reduction part, 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. It has a hole for receiving a large inner pin, seen including a motion converting mechanism for transmitting the rotation motion of the revolution member is converted into a rotational movement about the rotation axis of the motor side rotation member to a wheel side rotation member, a wheel The side rotation member is arranged on one axial side of the speed reduction part, and the rotary pump is arranged on the other axial direction of the speed reduction part .

  Preferably, the motion conversion mechanism further includes a stabilizer that is fastened to axial ends of the plurality of inner pins and that rotationally drives the rotary pump. The stabilizer uniformly distributes the load applied to some of the inner pins from the revolving member to all of the inner pins.

  As one embodiment of the rotary pump, the outer diameter surface has a tooth profile constituted by a cycloid curve, the inner rotor connected to the stabilizer and rotated integrally with the wheel side rotation member, and the tooth shape constituted by the inner diameter surface constituted by a cycloid curve A cycloid pump including an outer rotor that is rotatably supported by a casing and rotates around a point different from the rotation center of the inner rotor.

  Preferably, the inner rotor has a guide surface that abuts on the inner diameter surface of the casing and restricts radial displacement. Thereby, it can prevent that an inner rotor inclines with the radial load from a wheel.

  More preferably, the speed reducer lubrication mechanism further includes a cooling means for cooling the lubricating oil passing through the circulating oil passage. By supplying the cooled lubricating oil to the deceleration unit, it is possible to suppress a temperature rise due to heat generation at the contact portion.

  According to the present invention, the lubricating oil is circulated by the rotary pump installed in the casing, thereby providing an in-wheel motor drive device having excellent lubricity and high reliability.

  With reference to FIGS. 1-6, the in-wheel motor drive device 21 which concerns on one Embodiment of this invention is demonstrated.

  FIG. 5 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. 6 is a schematic view of the electric vehicle 11 as viewed from the rear. Referring to FIG. 5, 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. 6, the rear wheel 14 is accommodated in the wheel housing 12a of the chassis 12 and is fixed to the lower portion of the chassis 12 via a suspension device (suspension) 12b.

  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. 1-4, 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 II-II in FIG. 1, FIG. 3 is an enlarged view around the eccentric portions 25a and 25b, and FIG. It is the figure seen from the direction.

  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 that transmits the output from the speed reduction portion B to the drive wheels 14 is provided. The motor portion A and the speed reduction portion B are housed in the casing 22, and as shown in FIG. 6, the wheel housing 12 a of the electric vehicle 11. Installed inside.

  The motor part A includes a stator 23 fixed to the casing 22, a rotor 24 disposed at a position facing the inner side of the stator 23 with a radial gap, and a rotor 24 fixedly connected to the inner side of the rotor 24. It is a radial gap motor provided with the motor side rotation member 25 which rotates integrally. The rotor 24 includes a flange-shaped rotor portion 24a and a cylindrical hollow portion 24b, and is rotatably supported with respect to the casing 22 by rolling bearings 36a and 36b.

  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 has eccentric parts 25a and 25b in the speed reduction part B. One end of the motor-side rotating member 25 is fitted to the rotor 24 and is supported by the rolling bearing 36 c 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.

  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. The shaft portion 28b has a hollow structure, and a first inner raceway surface 33c of the wheel hub bearing 33 is formed on the outer diameter surface thereof.

  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.

  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. Further, in order to reduce the frictional resistance with the curved plates 26a and 26b, needle roller bearings 27a are provided at positions where they abut against the outer peripheral surfaces of the curved plates 26a and 26b.

  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. The stabilizer 31b evenly distributes the load applied to a part of the inner pins 31 from the curved plates 26a and 26b to all the inner pins 31. The cylindrical portion 31d is rotatably supported by the motor side rotating member 25 by needle roller bearings 31e.

  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 22c.

  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.

  In addition, referring to FIG. 2, at least one portion of casing 22 at the position of speed reduction portion B is provided with a lubricating oil discharge port 22 b for discharging the lubricating oil inside speed reduction portion B. A circulating oil passage 22 c 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 22b returns to the lubricating oil path 25c via the circulating oil path 22c.

  Here, a rotary pump 51 is provided between the lubricating oil discharge port 22b and the circulating oil passage 22c, forcibly circulating the lubricating oil. Referring to FIG. 4, 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 circulation flow path 22c.

  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.

  Furthermore, the speed reduction unit lubrication mechanism further includes a cooling unit that cools the lubricating oil that passes through the circulating oil passage 22c. In this embodiment, a cooling water channel 22e provided in the casing 22 and a heat sink 22f attached to the casing 22 are included. These cooling means contribute not only to the lubricating oil but also to the cooling of the motor part A.

  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 25 c flows out from the opening 42 b penetrating the lubricating oil supply port 25 d 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 reservoir 22d is supplied from the suction port 55 to the rotary pump 51 through the flow path in the casing 22, and is pumped from the discharge port 56 to the circulation oil path 22c. Then, the lubricating oil discharged from the rotary pump 51 returns to the lubricating oil path 25c via the circulating oil path 22c.

  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 the supply amount and the discharge amount of the lubricating oil to the speed reduction unit B both change with the rotation speed of the in-wheel motor drive device 21, the lubricating oil can always be circulated smoothly.

  Further, a part of the lubricating oil flowing through the circulating oil passage 22c reaches the speed reduction part B from between the casing 22 and the motor side rotation member 25 through the rolling bearing 36a, the motor part A, and the rolling bearing 36b. The lubricating oil flowing through this path lubricates the rolling bearings 36a and 36b and also functions as a cooling liquid for cooling the motor part A.

  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.

  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. In addition, a sealing member 32d is provided at the opening of the hollow portion 32a in order to prevent dust from entering the inside of the in-wheel motor drive device 21.

  The wheel hub bearing 33 is a double-row angular ball bearing that employs balls 33e as rolling elements. As the raceway surfaces of the balls 33e, a first outer raceway surface 33a (right side in the figure) and a second outer raceway surface 33b (left side in the figure) are provided on the inner diameter surface of the outer member 22a. A first inner raceway surface 33c facing the surface 33a is provided on the outer diameter surface of the wheel-side rotating member 28, and a second inner raceway surface 33d facing the second outer raceway surface 33b is provided on the outer diameter surface of the wheel hub 32, respectively. ing. A plurality of balls 33e are arranged between the first outer raceway surface 33a and the first inner raceway surface 33c and between the second outer raceway surface 33b and the second inner raceway surface 33d. The wheel hub bearing 33 includes a retainer 33f that holds the left and right rows of balls 33e, and a sealing member 33g that prevents leakage of a lubricant such as grease enclosed in the bearing and dust from the outside. Including.

  The wheel hub 32 and the wheel side rotation member 28 are fixed by diameter expansion caulking. “Diameter caulking” refers to a caulking jig (not shown) having an outer diameter slightly larger than the inner diameter of the shaft portion 28b of the wheel-side rotating member 28 in a state where the in-wheel motor driving device 21 is fixed. The wheel side rotating member 28 and the wheel hub 32 are plastically coupled by the plastic coupling portion 40 by press-fitting into the inner diameter portion 28b. By fixedly connecting the wheel-side rotating member 28 and the wheel hub 32 by the above method, the coupling strength can be significantly increased as compared with the case of fixing by fitting. Thereby, the wheel hub 32 can be stably held.

  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, an electromagnetic force generated by supplying an alternating current to the coil of the stator 23, and the rotor 24 composed of a permanent magnet or a magnetic material rotates. At this time, the rotor 24 rotates at a higher speed as a higher frequency voltage is applied to the coil.

  Thereby, when the motor side rotation member 25 connected to the rotor 24 rotates, the curved plates 26 a and 26 b revolve around the rotation axis of the motor side rotation 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, the provision of the needle roller bearings 27a, 31a at the positions where the outer pins 27 and the inner pins 31 come into contact with the curved plates 26a, 26b reduces the frictional resistance, thereby improving the transmission efficiency of the speed reducing portion B. .

  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.

  In the above-described embodiment, the example in which the circulating oil path 22c is provided inside the casing 22 has been described. However, the present invention is not limited to this. For example, a circulating oil path is provided outside the in-wheel motor drive device 21. Also good.

  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.

  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 24 in the drawing, the rotating member that rotates integrally with the rotor 24, and the casing 22 is non-rotatable and axial. A parking brake that locks the rotor 24 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 in which a flange formed on a part of a rotating member that rotates integrally with the rotor 24 and a friction plate installed on the casing 22 side are sandwiched by 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. However, the present invention is not limited to this, and a motor having an arbitrary configuration can be applied. 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. 5 showed 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 the figure which looked at the rotary pump of FIG. 1 from the axial direction. It is a top view of the electric vehicle which has the in-wheel motor drive device of FIG. FIG. 6 is a rear sectional view of the electric vehicle in FIG. 5. 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, 22c Circulating oil Path, 22d lubricating oil reservoir, 22e cooling water path, 22f heat sink, 23 stator, 24 rotor, 24a rotor section, 28a, 32b flange section, 24b, 32a hollow section, 28b shaft section, 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, 31e Needle roller bearing, 28, 110 Wheel Side rotating member, 29 counterweight, 30a , 30b Through-hole, 31, 109 Inner pin, 31b Stabilizer, 31c Annulus, 31d Cylindrical part, 32 Wheel hub, 32d, 33g Sealing member, 33 Wheel hub bearing, 40 Plastic coupling part, 33a, 33b, 43 Outer raceway Surface, 33c, 33d, 42a inner raceway surface, 42b opening, 33e ball, 33f cage, 36a, 36b, 36c, 41, 111 rolling bearing, 42 inner ring member, 44 cylindrical roller, 51 rotary pump, 52 inner rotor, 52a, 53a tooth tip portion, 52b, 53b tooth gap portion, 52c stepped portion, 54 pump chamber, 55 suction port, 56 discharge port.

Claims (6)

A motor unit for rotationally driving the motor side rotating member;
A speed reducer that decelerates the rotation of the motor side rotating member;
A wheel-side rotating member that transmits the rotation decelerated by the deceleration unit to the wheel side;
A casing for holding the motor part and the speed reduction part;
A wheel hub fixedly connected to the wheel side rotating member;
A reduction part lubrication mechanism provided in the casing and supplying lubricating oil to the reduction part;
The speed reducer lubrication mechanism is
A lubricating oil path provided inside the motor-side rotating member;
A lubricating oil supply port extending from the lubricating oil path toward the outer diameter surface of the motor-side rotating member;
A lubricating oil discharge port provided in the casing for discharging the lubricating oil from the speed reduction portion;
A lubricating oil reservoir that stores the lubricating oil discharged from the lubricating oil outlet in the casing;
A rotary pump that is disposed between the motor unit and the speed reduction unit in the casing and uses the rotation decelerated by the speed reduction unit to suck and discharge the lubricating oil from the lubricating oil storage unit ;
An in-wheel motor drive device comprising: a circulating oil path that connects the rotary pump and the lubricating oil path and returns the lubricating oil discharged from the rotary pump to the lubricating oil path. 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 peripheral engagement member fixed to the casing and engaged with an outer peripheral portion of the revolving member 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 revolving member and have a hole that is larger than the outer diameter of the inner pin by a predetermined amount and receives the inner pin, and rotates the revolving member. A motion conversion mechanism that converts the rotational motion about the rotational axis of the motor-side rotational member into a rotational motion and transmits the rotational motion to the wheel-side rotational member;
2. The in-wheel motor drive device according to claim 1, wherein the wheel-side rotation member is disposed on one axial direction of the speed reduction portion, and the rotary pump is disposed on the other axial direction of the speed reduction portion.   The in-wheel motor drive device according to claim 2, wherein the motion conversion mechanism further includes a stabilizer that is fastened to axial ends of the plurality of inner pins and that rotationally drives the rotary pump. The rotary pump is
An inner rotor that has a tooth profile constituted by a cycloid curve on the outer diameter surface, and is connected to the stabilizer and rotates integrally with the wheel-side rotation member;
4. A cycloid pump having a tooth profile constituted by a cycloid curve on an inner diameter surface, and an outer rotor that is rotatably supported by the casing and rotates around a point different from the rotation center of the inner rotor. The in-wheel motor drive device of description.   5. The in-wheel motor drive device according to claim 4, wherein the inner rotor has a guide surface that abuts against an inner diameter surface of the casing and regulates a radial displacement.   The in-wheel motor drive device according to any one of claims 1 to 5, wherein the speed reduction unit lubrication mechanism further includes a cooling unit that cools the lubricating oil that passes through the circulation oil passage.

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