JP2007239886A - In-wheel motor drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact, lightweight in-wheel motor drive unit having a wheel hub structure that can stably retain a drive wheel. <P>SOLUTION: The in-wheel motor drive unit 21 comprises a casing 22, a motor unit A, a decelerating unit B, a wheel hub 31, and a wheel hub bearing 33 for rotatably supporting the wheel hub 31 on the casing 22. The wheel hub bearing 33 includes first and second outside raceway surfaces 33a, 33b provided on the inner diameter surface of the casing 22, a first inside raceway surface 33c provided on the outer diameter surface of a wheel-side rotating member 30 to face the first outside raceway surface 33a, a second inside raceway surface 33d provided on the outer diameter surface of the wheel hub 31 to face the second outside raceway surface 33b, and a plurality of rolling elements 33e disposed between the outside raceway surfaces 33a, 33b and the inside raceway surfaces 33c, 33d. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-wheel motor drive apparatus that independently drives and rotates individual drive wheels.

  A conventional in-wheel motor drive device is described in, for example, Japanese Patent Application Laid-Open No. 2001-32914 (Patent Document 1). The in-wheel motor drive device described in the publication includes a motor that generates a driving force, a speed reducer that decelerates the rotation of the motor and transmits it to drive wheels, and a wheel hub that rotatably holds the drive wheels. Prepare.

  As a reduction gear, a planetary gear mechanism comprising a sun gear provided on an input shaft, an internal gear fixed to a casing, and a planetary gear disposed between the sun gear and the internal gear and coupled to an output shaft. Is adopted. Two planetary gear mechanisms are arranged in series to increase the reduction ratio.

  The wheel hub is fixedly connected to the output shaft of the speed reducer and is rotatably supported with respect to the casing by a wheel hub bearing. The wheel hub bearing holds an inner ring fitted to the outer diameter surface of the wheel hub, an outer ring fitted to the inner diameter surface of the casing, a plurality of rolling elements disposed between the inner ring and the outer ring, and a plurality of rolling elements. It is a double-row rolling bearing provided with a cage.

In an electric vehicle employing the in-wheel motor drive device configured as described above, it is not necessary to secure a space for the drive unit in the vehicle body, so the effective space in the vehicle increases, and the efficiency decreases and the weight increases due to the transmission system such as a differential device. It is described that it has the advantage of not.
JP 2001-32914 A

  Since the in-wheel motor drive device having the above-described configuration is disposed at the lower part of the suspension, a decrease in running stability due to an increase in so-called “unsprung weight” becomes a problem. This problem becomes more prominent with the recent miniaturization of the entire automobile.

  In addition, since the wheel hub bearing has an inner ring and an outer ring disposed between the wheel hub and the casing, there is a problem that the radial dimension increases. Also, it is difficult to say that the number of parts is large and the assemblability is good.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an in-wheel motor drive device having a wheel hub structure that is a small and light in-wheel motor drive device that can stably hold a drive wheel.

  The in-wheel motor drive device according to the present invention includes a casing, a motor unit that rotationally drives the motor-side rotation member, a reduction unit that decelerates the rotation of the motor-side rotation member and transmits the rotation to the wheel-side rotation member, and wheel-side rotation. A wheel hub fixedly connected to the member; and a wheel hub bearing that rotatably supports the wheel hub with respect to the casing. Paying attention to the wheel hub bearing, the outer member formed with the first and second outer raceway surfaces and the first inner raceway surface provided on the outer diameter surface of the wheel-side rotating member and facing the first outer raceway surface. A second inner raceway surface that is provided on the outer diameter surface of the wheel hub and faces the second outer raceway surface, between the first outer raceway surface and the first inner raceway surface, and between the second outer raceway surface and the second outer raceway surface. And a plurality of rolling elements arranged between the two inner raceways.

  By providing the outer raceway surface on the inner diameter surface of the casing and the inner raceway surface on the outer diameter surface of the wheel-side rotating member and the wheel hub as in the above configuration, the inner ring and outer ring as components of the bearing are omitted. Therefore, the radial dimension of the wheel hub bearing can be reduced. Or when making the dimension of radial direction the same dimension, since the diameter of a rolling element can be enlarged, it becomes possible to increase load capacity. Furthermore, the effect of improving the assemblability by reducing the number of parts can be expected.

  Preferably, the wheel hub has a cylindrical hollow portion, the wheel side rotating member is fitted inside the hollow portion of the wheel hub, and the inner diameter surface of the wheel hub and the outer diameter surface of the wheel side rotating member are: The wheel side rotating member is plastically coupled by expanding and caulking. As a result, the coupling strength between the wheel hub and the wheel-side rotating member is greatly improved, so that the drive wheels can be stably held.

  As one embodiment, the speed reduction unit is disposed between the sun gear and the internal gear, and is rotatably held by the sun gear provided on the motor-side rotation member, the internal gear fixed to the casing, and the wheel-side rotation member. A plurality of planetary gears.

  As another embodiment, the motor-side rotating member further includes an eccentric portion, and the speed reduction portion is rotatably held by the eccentric portion, and the rotation axis of the motor-side rotating member is centered with the rotation of the motor-side rotating member. A revolving member that performs revolving motion, an outer peripheral engagement member that engages with the outer peripheral portion of the revolving member to cause the revolving motion of the revolving member, and the revolving member that revolves around the rotation axis of the motor side rotating member. And a motion converting mechanism that converts the rotational motion into a wheel-side rotating member.

  By adopting a reduction mechanism that is compact and has a high reduction ratio as described above, sufficient torque can be transmitted to the drive wheels even when the motor portion has a low torque. As a result, a lightweight and small in-wheel motor drive device can be obtained.

  According to the present invention, it is possible to obtain an in-wheel motor drive device that is small and light and can stably hold a drive wheel.

  With reference to FIG. 6 and FIG. 7, the electric vehicle 11 provided with the in-wheel motor drive device which concerns on one Embodiment of this invention is demonstrated. 6 is a plan view of the electric vehicle 11, and FIG. 7 is a view of the electric vehicle 11 as viewed from the rear.

  6 and 7, an electric vehicle 11 includes an in-wheel that transmits driving force to a chassis 12, a front wheel 13 as a steering wheel, a rear wheel 14 as a driving wheel, and left and right rear wheels 14, respectively. And a motor drive device 15. As shown in FIG. 7, the rear wheel 14 is accommodated in a 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 15 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 15 is required to be reduced in size in order to secure a wider cabin space. Therefore, as the in-wheel motor drive device 15, in-wheel motor drive devices 21 and 41 according to an embodiment of the present invention as shown in FIG. 1 or FIG. 3 are employed.

  With reference to FIG. 1 and FIG. 2, the in-wheel motor drive device 21 which concerns on one Embodiment of this invention is demonstrated. FIG. 1 is a schematic cross-sectional view of the in-wheel motor drive device 21.

  First, referring to FIG. 1, an in-wheel motor drive device 21 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, and an output from the deceleration unit B. A wheel hub bearing portion C for transmitting to the drive wheel 14 is provided, and the motor portion A and the speed reduction portion B are accommodated in the casing 22 and attached to the wheel housing 12a of the electric vehicle 11 as shown in FIG.

  The motor unit A includes a stator 23 fixed to the casing 22, a rotor 24 disposed with a gap in the axial direction inside the stator 23, and a motor that fits inside the rotor 24 and rotates integrally with the rotor 24. This is an axial gap motor including the side rotation member 25. In addition, a sealing member 38 is provided on the end surface of the motor part A opposite to the speed reduction part B in order to prevent dust from entering the motor part A.

  The rotor 24 includes a flange-shaped rotor portion 24 a and a cylindrical hollow portion 24 b, and is rotatably supported with respect to the casing 22 by a double row rolling bearing 34. In addition, a sealing member 35 is provided between the casing 22 and the rotor 24 in order to prevent the lubricant encapsulated in the speed reduction part B from entering the motor part A.

  The motor-side rotating member 25 is spline-fitted into the hollow portion 24b of the rotor 24, and is held rotatably with respect to the casing 22 and the wheel-side rotating member 30 by rolling bearings 36 and 37 on the left and right sides of the speed reduction portion B. .

  The speed reduction part B includes a sun gear 26 provided on the motor-side rotating member 25, an internal gear 27 fixed to the casing 22, a plurality of planetary gears 28 disposed between the sun gear 26 and the internal gear 27, The planetary gear mechanism includes a planetary carrier shaft 29 that rotatably supports the planetary gear 28 by needle roller bearings, and a wheel-side rotating member 30 that takes out the revolution motion of the planetary carrier shaft as an output.

  The wheel-side rotating member 30 includes a flange portion 30a and a cylindrical hollow portion 30b. The end surface of the flange portion 30a has holes for fixing the planet carrier shaft 29 at equal intervals on the circumference centered on the rotation axis, and the outer diameter surface of the hollow portion 30b is fitted with the inner diameter surface of the wheel hub 31. Match.

  The wheel hub bearing portion C includes a wheel hub 31 fixedly connected to the wheel-side rotating member 30 and a wheel hub bearing 33 that holds the wheel hub 31 rotatably with respect to the casing 22. The wheel hub 31 has a cylindrical hollow portion 31a and a flange portion 31b. The wheel-side rotating member 30 is fitted to the inner diameter surface of the hollow portion 31a, and the driving wheel 14 (not shown) is fixedly connected to the flange portion 31b by a bolt 31c. In addition, a sealing member 32 is provided at the opening of the hollow portion 31a 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 32a. A first inner raceway surface 33c facing the surface 33a is provided on the outer diameter surface of the wheel-side rotating member 30, 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. Further, the outer member 22 a having the first and second outer ring raceway surfaces 33 a and 33 b is fixed to the casing 22 by bolts 39 from the viewpoint of the incorporation of the wheel hub bearing 33.

  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 and the motor-side rotating member 25 configured by a permanent magnet or a direct current electromagnet rotate. At this time, the rotor 24 and the motor-side rotating member 25 rotate at a higher speed as a high-frequency voltage is applied to the coil.

  Thereby, the sun gear 26 provided in the motor side rotation member 25 rotates. At this time, since the planetary gear 28 meshes with both the sun gear 26 and the internal gear 27, the planetary gear 28 rotates in the direction opposite to the rotation direction of the motor side rotation member 25 and is the same as the rotation direction of the motor side rotation member 25. Revolves in the direction.

The revolving motion of the planetary gear 28 becomes the output of the speed reduction unit B via the planetary carrier shaft 29 and is transmitted to the wheel hub bearing unit C. At this time, assuming that the number of teeth of the sun gear 26 is n ₁ and the number of teeth of the internal gear 27 is n ₂ , the rotation of the motor-side rotating member 25 is decelerated at the reduction ratio r expressed by Equation 1 to rotate on the wheel side. It is transmitted to the member 30. The reduction ratio r is set to about 1/3 to 1/6 from the viewpoint of gear strength and the like.

  The in-wheel motor drive device 21 having the above-described configuration is provided by providing the outer raceway surfaces 33 a and 33 b of the wheel hub bearing 33 on the outer member 22 a and providing the inner raceway surfaces 33 c and 33 d on the wheel side rotation member 30 and the wheel hub 31. The outer ring and inner ring as components of the bearing can be omitted. As a result, the radial dimension of the wheel hub bearing 33 can be reduced. Or when making the dimension of radial direction the same dimension, since the diameter of the ball | bowl 33e can be enlarged, it becomes possible to increase load capacity. Furthermore, the improvement effect of assembly man-hour by reducing the number of parts can also be expected.

  In the in-wheel motor drive device 21 configured as described above, the outer diameter surface of the wheel-side rotating member 30 and the inner diameter surface of the wheel hub 31 are plastically coupled by expanding and caulking the wheel-side rotating member 30. FIG. 2 is a diagram illustrating a method of joining the wheel-side rotating member and the wheel hub by diameter expansion caulking.

  With reference to FIG. 2, as a method of assembling the wheel hub bearing portion C, first, a cage 33 f accommodating balls 33 e is placed on a first inner raceway surface 33 c provided on the wheel-side rotating member 30. Next, the outer member 22 a is disposed at a position where the first outer raceway surface 33 a properly contacts the ball 33 e and is fixed to the casing 22 by the bolt 39. Next, the wheel hub 31 is moved to the wheel-side rotating member 30 so that the ball 33e properly contacts the second outer raceway surface 33b with the cage 33f containing the ball 33e placed on the second inner raceway surface 33d. Fit into.

  In this state, the wheel-side rotating member 30 and the wheel hub 31 are merely fixed by fitting, so that when the large moment load is applied when the electric vehicle 11 turns, the wheel hub 31 is axially moved. There is a risk of slipping. This causes a rotation failure of the wheel hub bearing 33 and the wheel hub 31 cannot be stably held.

  Therefore, the outer diameter surface of the wheel-side rotating member 30 and the inner diameter surface of the wheel hub 31 are plastically coupled by expanding and caulking. Specifically, the in-wheel motor drive device 21 is fixed, and a caulking jig 40 having an outer diameter slightly larger than the inner diameter of the hollow portion 30b of the wheel-side rotating member 30 is press-fitted into the hollow portion 30b.

  Thereby, the wheel side rotation member 30 and the wheel hub 31 are plastically coupled at the plastic coupling portion 40a. By fixedly connecting the wheel-side rotating member 30 and the wheel hub 31 by the above method, the coupling strength can be significantly increased as compared with the case of fixing by fitting. Thereby, the wheel hub 31 can be stably held.

  In the above embodiment, the example in which the motor-side rotating member 25 and the sun gear 26 are integrally formed has been shown. However, the present invention is not limited to this, and the motor-side rotating member 25 and the sun gear 26 are formed separately. Then, the sun gear 26 may be fixed at a predetermined position of the motor side rotation member 25 by fitting or the like. Similarly, although the example in which the internal gear 27 is directly formed on the inner diameter surface of the casing 22 is shown, the present invention is not limited to this, and the independently formed internal gear 27 may be fitted into the casing 22.

  Moreover, in the wheel hub bearing 33 of the said embodiment, although the 1st and 2nd outer raceway surface 33a, 33b showed the example formed in the internal-diameter surface of the outward member 22a, it does not restrict to this but in the casing 22 It is good also as forming directly.

  Next, an in-wheel motor drive device 41 according to another embodiment of the present invention will be described with reference to FIGS. 3 is a schematic cross-sectional view of the in-wheel motor drive device 41, FIG. 4 is a cross-sectional view taken along IV-IV in FIG. 3, and FIG. 5 is an enlarged view around the eccentric portions 45a and 45b in FIG.

  Referring to FIG. 3, the in-wheel motor drive device 41 includes a motor unit A having the same configuration as in FIG. 1, a deceleration unit B that decelerates and outputs the rotation of the motor unit A, and an output from the deceleration unit B. A wheel hub bearing portion C having the same configuration as that shown in FIG. 1 is transmitted to the drive wheel 14, and the motor portion A and the speed reduction portion B are housed in a casing, and as shown in FIG. 7, inside the wheel housing 32a of the electric vehicle 11 Attached to. The motor part A and the wheel hub bearing part C have the same configuration as the in-wheel motor drive device 21 shown in FIG.

  The motor side rotation member 45 is arranged 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 45 a and 45 b in the speed reduction part B. Further, it is supported by rolling bearings 46, 47 and 48 at both ends of the motor part A and the left end of the speed reducing part B. Further, the two eccentric portions 45a and 45b are provided with a 180 ° phase change so as to cancel out the centrifugal force caused by the eccentric motion.

  The deceleration part B is held at a fixed position on the casing 42 and curved plates 46a, 46b as revolving members that are rotatably held by the eccentric parts 45a, 45b, and engages with the outer peripheral parts of the curved plates 46a, 46b. A plurality of outer pins 47 as outer peripheral engagement members, a motion conversion mechanism that transmits the rotation of the curved plates 46 a and 46 b to the wheel side rotation member 56, and a counterweight 49 are provided.

  Referring to FIG. 4, the curved plate 46 a has a plurality of corrugations composed of trochoidal curves such as epitrochoids on the outer periphery, and a plurality of through holes 50 a and 50 b penetrating from one end face to the other end face. Have A plurality of through holes 50a are provided at equal intervals on the circumference centered on the rotation axis of the curved plate 46a, and receive inner pins 51 described later. The through hole 50b is provided at the center of the curved plate 46a and passes through the eccentric portion 45a.

  The curved plate 46a is supported by the rolling bearing 52 so as to be rotatable with respect to the eccentric portion 45a. The rolling bearing 52 is fitted to the eccentric portion 45a, an inner ring 52a having an inner raceway surface on the outer diameter surface, an outer ring 52b fitted to the inner wall surface of the through hole 50b and having an outer raceway surface on the inner diameter surface, A deep groove ball bearing including a plurality of balls 52c as rolling elements disposed between an inner ring 52a and an outer ring 52b, and a cage (not shown) that holds the plurality of balls 52c.

  The outer pins 47 are provided at equal intervals on a circumferential track centering on the rotation axis of the motor side rotation member 45. This coincides with the revolution trajectory of the curved plates 46a and 46b. Therefore, when the curved plates 46a and 46b revolve, the curved waveform and the outer pin 47 engage with each other, and the curved plates 46a and 46b rotate. Cause it to occur. Further, in order to reduce the contact resistance with the curved plates 46a and 46b, a needle roller bearing 47a is provided at a position where the curved plates 46a and 46b come into contact with the outer peripheral surface.

  The counterweight 49 has a disc shape and has a through-hole that fits with the motor-side rotating member 45 at a position off the center. Each counterweight 49 is arranged to cancel the couple generated by the rotation of the curved plates 46a and 46b. 45a and 45b are arranged outside the eccentric part and with a 180 ° phase change.

  Here, as shown in FIG. 5, the curved plates 46a and 46b and the counterweight 49 have a central point G between the two curved plates 46a and 46b, and the central point G and the centers of the curved plates 46a and 46b. Is L1, the distance between the center point G and each counterweight 49 is L2, the mass of the curved plate 46a on the right side of the central point G and the counterweight 49 is m1, the curved plate 46b on the left side of the central point G, and the counterweight. When the mass of 49 is m2, and the eccentric amounts of the center of gravity of the center of gravity are ε1 and ε2, respectively, the relationship satisfies L1 × m1 × ε1 = L2 × m2 × ε2.

  The motion conversion mechanism includes a plurality of inner pins 51 held by the wheel-side rotating member 56 and through holes 50a provided in the curved plates 46a and 46b. The inner pins 51 are provided at equal intervals on a circumferential track centering on the rotation axis of the wheel side rotation member 56. Further, in order to reduce the contact resistance with the curved plates 46a and 46b, a needle roller bearing 51a is provided at a position in contact with the inner wall surface of the through hole 50a of the curved plates 46a and 46b. On the other hand, the through hole 50a is provided at a position corresponding to each of the plurality of inner pins 51, and the inner diameter dimension of the through hole 50a is predetermined from the outer diameter dimension of the inner pin 51 (maximum outer diameter including the needle roller bearing 51a). The minute is set.

  The outer diameter of the inner pin 51 is smaller than the inner diameter of the through hole 50a, and the inner pin 51 and the inner peripheral surface of the through hole 50a rotate while repeating a contact state and a non-contact state. From the viewpoint of smoothly transmitting the rotation to the drive wheel 14, it is desirable to provide a plurality of inner pins 51.

  The operation principle of the in-wheel motor drive device 41 configured as described above 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 43, and the rotor 44 constituted by a permanent magnet or a direct current electromagnet rotates. At this time, the rotor 44 rotates at a higher speed as a higher frequency voltage is applied to the coil.

  As a result, when the motor-side rotating member 45 connected to the rotor 44 rotates, the curved plates 46 a and 46 b revolve around the rotation axis of the motor-side rotating member 45. At this time, the outer pin 47 engages with the curved waveform of the curved plates 46 a and 46 b to rotate the curved plates 46 a and 46 b in the direction opposite to the rotation of the motor side rotating member 45.

  The inner pin 51 inserted through the through hole 50a comes into contact with the inner wall surface of the through hole 50a as the curved plates 46a and 46b rotate. At this time, since the inner diameter dimension of the through hole 50a is set larger than the outer diameter dimension of the inner pin 51, the inner pin 51 and the inner wall surface of the through hole 50a are in contact with each other while repeating a contact state and a non-contact state. Exercise. As a result, the revolving motion of the curved plates 46 a and 46 b is not transmitted to the inner pin 51, and only the rotational motion of the curved plates 46 a and 46 b is transmitted to the wheel hub bearing portion C via the wheel-side rotating member 56.

  At this time, since the rotation of the motor side rotation member 45 is decelerated by the speed reduction unit B and transmitted to the wheel side rotation member 56, it is necessary for the drive wheel 14 even when the low torque, high rotation type motor unit 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 47 and Z _B is the number of waveforms of the curved plates 46a and 46b. The In the embodiment shown in FIG. 4, because 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 reduction ratio without using a multi-stage configuration, a compact and high reduction ratio in-wheel motor drive device can be obtained. Further, by providing the needle roller bearings 47a and 51a at the positions where the outer pins 47 and the inner pins 51 come into contact with the curved plates 46a and 46b, the contact resistance is reduced, so that the transmission efficiency of the speed reduction portion B is improved. .

  Since the curved plates 46a and 46b revolve at high speed while engaging with the outer pin 47, a large radial load is applied to the rolling bearing 52 that supports the curved plates 46a and 46b. However, there is a possibility that the rolling bearing 52 having a sufficient load capacity cannot be arranged in a limited space inside the speed reduction portion B. In addition, this problem becomes more conspicuous with the recent demand for a compact electric vehicle 11.

  Therefore, the outer race 52b can be omitted by providing the outer raceway surface of the rolling bearing 52 on the inner wall surface of the through hole 50b of the curved plates 46a and 46b. As a result, the gap between the inner raceway surface and the outer raceway surface is increased, so that it is possible to employ balls 52c having a large diameter or increase the number of balls 52c. As a result, the load capacity can be improved without changing the overall size of the rolling bearing 52, so that an in-wheel motor drive device having excellent durability and high reliability can be obtained. In addition, it can be expected to reduce the product cost by reducing the number of parts.

  In the above-described embodiment, two curved plates 46a and 46b of the speed reduction unit B are provided with a 180 ° phase change. However, the number of curved plates can be arbitrarily set. For example, three curved plates are provided. In such a case, it is preferable to change the 120 ° phase.

  Moreover, although the motion conversion mechanism in said embodiment showed the example comprised by the inner pin 51 fixed to the wheel side rotation member, and the through-hole 50a provided in the curve boards 46a and 46b, Without limitation, any configuration capable of transmitting the rotation of the speed reduction portion B to the wheel hub 53 can be employed. 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 output member.

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

  In the description of the operation in each of the above embodiments, 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. When the vehicle decelerates or goes down the hill, the power from the drive wheel 14 side is converted into high-rotation low-torque rotation by the reduction unit B and transmitted to the motor unit A, and the motor unit A generates power. You may do it. 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.

  Furthermore, a brake can be added to the configuration of each of the above embodiments. For example, in the configuration of FIG. 1, in a space on the right side of the rotor 24 in the drawing, a rotating member that rotates integrally with the rotor 24, a piston that is non-rotatable and axially movable in the casing 22, and this piston is operated It may be a parking brake that disposes a cylinder and locks the rotor 24 by fitting the piston and the rotating member when the vehicle is stopped.

  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.

  By adopting the in-wheel motor drive devices 21 and 41 according to the above embodiments 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 embodiment, an example in which angular ball bearings are employed as the wheel hub bearings 33 and 54 is shown. However, the present invention is not limited thereto, and examples thereof include cylindrical roller bearings, tapered roller bearings, needle roller bearings, Regardless of whether the rolling element is a roller or a ball, such as a self-aligning roller bearing, a deep groove ball bearing, an angular ball bearing, and a four-point contact ball bearing, any rolling bearing can be applied. Similarly, any type of bearing can be adopted for bearings arranged in other locations.

  Further, in each of the above embodiments, the motor part A is provided with an axial gap between the stator and the rotor, but the motor part A is provided with a radial gap between the stator and the rotor, etc. Any type can be employed.

  Further, although the electric vehicle 11 shown in FIG. 6 shows an example in which the rear wheel 14 is a drive wheel, the present invention is not limited to this, and the front wheel 13 may be a drive wheel or a four-wheel drive vehicle. . In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and should be understood as including, for example, a hybrid vehicle.

  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 a figure which shows the method of diameter expansion caulking with the wheel side rotation member and wheel hub of the in-wheel motor drive device of FIG. It is a figure which shows the in-wheel motor drive device which concerns on other embodiment of this invention. It is sectional drawing in IV-IV of FIG. FIG. 4 is an enlarged view around the eccentric portion of FIG. 3. It is a top view of the electric vehicle which employ | adopted the in-wheel motor drive device which concerns on this invention. It is the figure which looked at the electric vehicle of FIG. 6 from back.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Electric vehicle, 12 Chassis, 12a Wheel housing, 12b Suspension device, 13 Front wheel, 14 Rear wheel, 15, 21, 41 In-wheel motor drive device, 22, 42 Casing, 22a, 42a Outer member, 23, 43 Stator, 24, 44 Rotor, 25, 45 Motor side rotating member, 45a, 45b Eccentric part, 26 Sun gear, 27 Internal gear, 28 Planetary gear, 29 Planet carrier shaft, 30, 56 Wheel side rotating member, 24a, 30a, 31b, 53b Flange portion, 24b, 30b, 31a, 53a Hollow portion, 31, 53 Wheel hub, 32, 33g, 38, 35 Seal member, 33, 54 Wheel hub bearing, 33a, 54a First outer raceway surface, 33b, 54b First 2 outer raceway surface, 33c, 54c first inner raceway surface, 33d, 54d second inner raceway , 33e, 54e Ball, 33f Cage, 34, 36, 37, 46, 47, 48, 52 Rolling bearing, 39, 53c Bolt, 40 Caulking jig, 40a Wide diameter caulking part, 46a, 46b Curved plate, 47 Outer pin, 47a, 51a Needle roller bearing, 49 counterweight, 50a, 50b through hole, 51 inner pin.

Claims (4)

A casing,
A motor unit for rotationally driving the motor side rotation member;
A speed reducer that decelerates the rotation of the motor-side rotating member and transmits it to the wheel-side rotating member;
A wheel hub fixedly connected to the wheel side rotating member;
A wheel hub bearing that rotatably supports the wheel hub with respect to the casing;
The wheel hub bearing is
An outer member having first and second outer raceways formed thereon;
A first inner raceway surface provided on an outer diameter surface of the wheel-side rotating member and facing the first outer raceway surface;
A second inner raceway surface provided on an outer diameter surface of the wheel hub and facing the second outer raceway surface;
An in-wheel motor drive comprising a plurality of rolling elements disposed between the first outer raceway surface and the first inner raceway surface and between the second outer raceway surface and the second inner raceway surface; apparatus. The wheel hub has a cylindrical hollow portion,
The wheel side rotating member is fitted inside the hollow portion of the wheel hub,
2. The in-wheel motor drive device according to claim 1, wherein an inner diameter surface of the wheel hub and an outer diameter surface of the wheel-side rotating member are plastically coupled by expanding and caulking the wheel-side rotating member. The deceleration part is
A sun gear provided on the motor side rotating member;
An internal gear fixed to the casing;
The in-wheel motor drive device according to claim 1 or 2 including a plurality of planetary gears rotatably held by said wheel side rotation member and arranged between said sun gear and said internal gear. The motor side rotating member further has an eccentric part,
The deceleration part is
A revolving member that is rotatably held by the eccentric part and performs a revolving motion around its rotation axis as the motor side rotation member rotates;
An outer peripheral engagement member that engages with an outer peripheral portion of the revolution member and causes the revolution member to rotate.
4. A motion conversion mechanism that converts a rotation motion of the revolution member into a rotation motion centered on a rotation axis of the motor-side rotation member and transmits the rotation motion to the wheel-side rotation member. In-wheel motor drive device.

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