JP2007237927A - In-wheel motor drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and light-weight in-wheel motor drive device having an excellent durability and high reliability. <P>SOLUTION: The in-wheel motor drive device 21 is equipped with a casing 22, a motor part A, a speed reduction part B, and a wheel hub 32. The motor part A is a radial gap motor including a stator 23 fixed to the casing 22, and a rotor 24 which is fixedly connected to a motor side rotational member 25, and disposed at the opposed position having a radial gap with the stator 23. The speed reduction part B comprises curved line plates 26a, 26b which are rotatably held on eccentric parts 25a, 25b, and perform an orbital motion around the rotational axis accompanied with the rotation of the motor side rotational member 25, an outer pin 27 which is engaged with the outer peripheral part of the curved line plates 26a, 26b to generate the rotation motion of the curved line plates 26a, 26b, and a motion conversion mechanism which converts the rotation motion of the curved line plates 26a, 26b to the rotary motion around the rotational axis of the motor side rotational member 25 to transmit to the wheel side rotational member 28. <P>COPYRIGHT: (C)2007,JPO&INPIT

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 coaxially connected via a reduction gear.

  A conventional in-wheel motor drive device is described in, for example, Japanese Patent Application Laid-Open No. 2005-7914 (Patent Document 1). The in-wheel motor drive device described in the publication discloses a motor that generates a driving force, a wheel hub that connects a tire, and a motor and a wheel hub that decelerate the rotation of the rotor of the motor and transmit it to the tire. A reduction gear. This reduction gear employs a parallel shaft gear mechanism formed by combining a plurality of gears having different numbers of teeth.

  Such an in-wheel motor drive device in which the output shaft of the electric motor and the wheel hub are coaxially connected via a speed reducer eliminates the need for a large-scale power transmission mechanism such as a propeller shaft and a differential. It is attracting attention in terms of weight reduction and compactness. However, the in-wheel motor drive device attached to the unsprung portion of the vehicle has a drawback that the ride comfort becomes worse due to the increase of the unsprung weight, and has not yet been put into practical use.

  The output torque of the electric motor and the motor volume (weight) are almost proportional, and in order to obtain a large output sufficient to drive the wheels of the vehicle with a small motor volume, high-speed rotation is inevitable. It is necessary to incorporate a reduction gear between the output shaft and the hub. For this reason, since the weight of the reduction gear to be incorporated is meaningless, there is a need for a reduction gear that is compact and can provide a large reduction ratio in the in-wheel motor drive device.

In addition, as a reduction device for an electric vehicle, there is one in which a planetary gear reduction device is incorporated as a reduction device between an output shaft of an electric motor and a wheel hub (see, for example, Patent Document 2). Although what is described in Patent Document 2 is not an in-wheel motor drive device in which the electric motor and the speed reducer are mounted under the spring, the planetary gear speed reducer is provided in two stages, and the output from the second stage planetary gear speed reducer is Output is distributed to the left and right unsprung wheels via the drive shaft.
JP 2005-7914 A Japanese Patent Laid-Open No. 5-332401 (Fig. 1-3)

  The reduction ratios of the parallel shaft gear mechanism and the planetary gear mechanism employed in the reduction gears described in the above publications are 1/2 to 1/3 for the former and 1/3 for the latter from the viewpoint of gear strength and the like. Generally, it is set to about １ ／. This is insufficient as a reduction ratio of a reduction gear mounted on the in-wheel motor drive device, and the reduction gear needs to have a multistage configuration in order to obtain a sufficient reduction ratio. This leads to an increase in the weight and size of the speed reducer, and is inappropriate for an in-wheel motor drive device that needs to be made compact.

  Further, the planetary gear reducer described in Patent Document 2 can obtain a large reduction ratio as compared with the parallel shaft gear. There is a problem that the number of parts is large and it is difficult to reduce the size.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an in-wheel motor drive device that is small, light, excellent in durability, and high in reliability.

  An in-wheel motor drive device according to the present invention includes a casing, a motor unit that rotationally drives a motor-side rotating member having an eccentric part, and a deceleration unit that decelerates the rotation of the motor-side rotating member and transmits the rotation to the wheel-side rotating member. And a wheel hub fixedly connected to the wheel side rotating member. The motor unit is a radial gap motor including a stator fixed to the casing and a rotor fixedly connected to the motor-side rotation member and disposed at a position facing the stator with a radial gap therebetween. The speed reduction part is rotatably held by the eccentric part and engages with a revolution member that performs a revolution movement around its rotation axis as the motor side rotation member rotates, and an outer periphery of the revolution member to revolve. An outer peripheral engagement member that causes the rotation of the member, and a motion conversion mechanism that converts the rotation of the revolving member into a rotation about the rotation axis of the motor-side rotation member and transmits the rotation to the wheel-side rotation member. Including.

  By adopting a compact speed reducing portion having a high speed reduction ratio as described above, it is possible to transmit sufficient torque 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.

  Further, the radial gap motor employed in the present invention can reduce the radial dimension of the rotor as compared with the axial gap motor, so that the radial dimension of the motor portion can be reduced and at the time of high-speed rotation. This has the advantage that the peripheral speed of the outer diameter portion of the rotor can be kept low. Thereby, troubles such as breakage of the rotor during high-speed rotation can be suppressed, so that a highly reliable in-wheel motor drive device can be obtained.

  According to the present invention, it is possible to obtain an in-wheel motor drive device capable of transmitting sufficient torque to the drive wheels even when a low torque motor is employed. In addition, by adopting a radial gap motor in the motor unit, the radial dimension of the motor unit can be reduced, and troubles such as vibration and breakage of the rotor accompanying high-speed rotation can be prevented, resulting in high reliability. An in-wheel motor drive device can be obtained.

  With reference to FIG. 4 and FIG. 5, the electric vehicle 11 provided with the in-wheel motor drive device which concerns on one Embodiment of this invention is demonstrated. 4 is a plan view of the electric vehicle 11, and FIG. 5 is a view of the electric vehicle 11 as viewed from the rear.

  Referring to FIG. 4, 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. 15. Referring to FIG. 5, 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 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, an in-wheel motor drive device 21 according to an embodiment of the present invention as shown in FIG.

  With reference to FIGS. 1-3, 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, and FIG. 3 is an enlarged view around the eccentric portions 25a and 25b in FIG.

  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 part A includes a stator 23 as a stator fixed to the casing 22 by bolts 23a, a rotor 24 as a rotor arranged at a position facing the inner side of the stator 23 with a radial gap, and a rotor A radial gap motor including a motor-side rotating member 25 that is fixedly connected to the inside of the rotor 24 and rotates integrally with the rotor 24. Further, a sealing member 34 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 35. In addition, a sealing member 36 is provided between the casing 22 and the rotor 24 in order to prevent the lubricant encapsulated in the speed reduction unit B from entering the motor unit A.

  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 rolling bearings 37 and 38 at both ends of the speed reduction unit 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 that transmits the rotation of the curved plates 26 a and 26 b to the wheel-side rotation member 28, and a counterweight 29 are provided.

  The wheel side rotation member 28 has a flange portion 28a and a cylindrical hollow portion 28b. The end surface of the flange portion 28a has holes for fixing the inner pins 31 at equal intervals on the circumference around the rotation axis of the wheel side rotation member 28, and the outer diameter surface of the hollow portion 28b is the wheel hub 32. Mates with the inner diameter surface of.

  Referring to FIG. 2, the curved plate 26 a has a plurality of corrugations composed of trochoidal curves such as epitrochoids on the outer peripheral portion, and a plurality of through holes 30 a and 30 b penetrating from one end face to the other end face. Have 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 inner pins 31 described later. The through hole 30b is provided at the center of the curved plate 26a and passes through the eccentric portion 25a.

  The curved plate 26a is rotatably supported by the rolling bearing 39 with respect to the eccentric portion 25a. This rolling bearing 39 is fitted to the eccentric portion 25a, an inner ring 39a having an inner raceway surface on the outer diameter surface, an outer ring 39b fitted to the inner wall surface of the through hole 30b and having an outer raceway surface on the inner diameter surface, It is a deep groove ball bearing provided with balls 39c as a plurality of rolling elements disposed between an inner ring 39a and an outer ring 39b, and a cage (not shown) that holds the plurality of balls 39c.

  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. This coincides with the revolution trajectory of the curved plates 26a and 26b. Therefore, when the curved plates 26a and 26b revolve, the curved waveform and the outer pin 27 engage with each other, and the curved plates 26a and 26b rotate. Cause it to occur. Further, in order to reduce the contact resistance with the curved plates 26a, 26b, a needle roller bearing 27a is provided at a position in contact with the outer peripheral surface of the curved plates 26a, 26b.

  The counterweight 29 has a disc shape and has a through-hole that fits with the motor-side rotating member 25 at a position off the center. Each counterweight 29 is arranged to cancel the couple generated by the rotation of the curved plates 26a and 26b. Arranged on the outside of 25a and 25b with a 180 ° phase change from the eccentric part.

  Here, as shown in FIG. 3, the curved plates 26a and 26b and the counterweight 29 have a center point G between the two curved plates 26a and 26b, and a center point G and the centers of the curved plates 26a and 26b. Is L1, the distance between the center point G and each counterweight 29 is L2, the mass of the curved plate 26a on the right side of the central point G and the weight of the counterweight 29 is m1, the curved plate 46b on the left side of the central point G, and the counterweight. When the mass of 29 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 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 rotating member 28, one end is fixed to the wheel-side rotating member 28, and the other end is from a through hole 30 a. A retaining portion 31b is provided to prevent the slipping out. Further, in order to reduce the contact resistance with the curved plates 26a and 26b, needle roller bearings 31a are provided at positions where the curved plates 26a and 26b come into contact with the inner wall surfaces of the through holes 30a. 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 dimension of the through hole 30a is predetermined from the outer diameter dimension of the inner pin 31 (the maximum outer diameter including the needle roller bearing 31a). The minute is set.

  The outer diameter of the inner pin 31 is smaller than the inner diameter of the through hole 30a, and the inner pin 31 and the inner peripheral surface of the through hole 30a 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 31.

  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 wheel-side rotating member 28 is fitted to the inner diameter surface of the hollow portion 32a, and the drive wheel 14 (not shown) 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. 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 22 b from the viewpoint of the incorporation of the wheel hub bearing 33.

  The in-wheel motor drive device 21 configured as described above has the outer raceway surfaces 33a and 33b of the wheel hub bearing 33 provided on the outer member 22a, and the inner raceway surfaces 33c and 33d provided on the wheel side rotation member 28 and the wheel hub 32. 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 the assemblability by reducing the number of parts can also be expected.

  Here, it is conceivable to employ an axial gap motor 41 as shown in FIG. The axial gap motor 41 includes a casing 42, a stator 43 fixed to the casing 42, and a rotor 44 disposed at a position facing the stator 43 with an axial interval therebetween, and the rotor 44 is a motor-side rotating member. 45 is fixedly connected.

  Such an axial gap motor 41 has an advantage that the axial dimension of the motor part A can be shortened as compared with the radial gap motor. On the other hand, since the radial dimension of the rotor 44 is increased, there is a problem that the radial dimension of the motor portion A is increased as compared with the radial gap motor.

  Moreover, the centrifugal force at the time of motor rotation becomes large at the outer diameter portion 44a of the rotor 44 having a large radial dimension. As a result, for example, when the rotor 44 is tilted with respect to the motor-side rotating member 45 due to a manufacturing error or the like, vibration due to surface vibration at the outer diameter portion 44a increases, or the rotor 44 is centrifugally broken. There is also a risk of doing. This is a serious problem as a motor for the in-wheel motor drive device 21 that requires high-speed rotation.

  Therefore, by adopting a radial gap motor as shown in FIG. 1 for the motor part A, it is possible to apply the rotor 24 having a small radial dimension of the flange part 24a. As a result, even when the motor unit A is rotated at a high speed, troubles such as vibration and breakage of the rotor 24 due to centrifugal force and the like can be prevented, and the in-wheel motor drive device 21 with high reliability can be obtained.

  In the in-wheel motor drive device 21 configured as described above, the outer diameter surface of the wheel side rotation member 28 and the inner diameter surface of the wheel hub 32 are plastically coupled by expanding and caulking the wheel side rotation member 28.

  First, as a method of assembling the wheel hub bearing portion C, first, the cage 33f that accommodates the balls 33e is placed on the first inner raceway surface 33c provided on the wheel-side rotating member 28. Next, the outer member 22a is disposed at a position where the first outer raceway surface 33a properly contacts the ball 33e, and is fixed to the casing 22 by a bolt 22b. Next, the wheel hub 32 is moved to the wheel-side rotating member 28 so that the ball 33e properly contacts the second outer raceway surface 33b in a state where the retainer 33f containing the ball 33e is placed on the second inner raceway surface 33d. Fit into.

  In this state, the wheel-side rotating member 28 and the wheel hub 32 are merely fixed by fitting, so that when the large moment load is applied when the electric vehicle 11 turns, the wheel hub 32 is axially moved. There is a risk of slipping. This causes a rotation failure of the wheel hub bearing 33, and the wheel hub 32 cannot be stably held.

  Therefore, the outer diameter surface of the wheel side rotation member 28 and the inner diameter surface of the wheel hub 32 are plastically coupled by expanding and caulking. Specifically, the in-wheel motor drive device 21 is fixed, and a crimping jig (not shown) having an outer diameter slightly larger than the inner diameter of the hollow portion 28b of the wheel-side rotating member 28 is press-fitted into the hollow portion 28b. To do.

  As a result, the wheel side rotation member 28 and the wheel hub 32 are plastically coupled at the plastic coupling portion 40. 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 constituted by a permanent magnet or a direct current electromagnet 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. At this time, since the inner diameter of the through hole 30a is set larger than the outer diameter of the inner pin 31, the inner pin 31 and the inner wall surface of the through hole 30a 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 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 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 27a and 31a at positions where they contact the curved plates 26a and 26b of the outer pin 27 and the inner pin 31, the contact resistance is reduced, so that the transmission efficiency of the speed reduction portion B is improved. .

  Since the curved plates 26a and 26b revolve at high speed while engaging with the outer pin 27, a large radial load is applied to the rolling bearing 39 that supports the curved plates 26a and 26b. However, there is a possibility that the rolling bearing 39 having a sufficient load capacity cannot be arranged in a limited space inside the deceleration part B. In addition, this problem becomes more conspicuous with the recent demand for a compact electric vehicle 11.

  Therefore, the outer race 39b can be omitted by providing the outer raceway surface of the rolling bearing 39 on the inner wall surface of the through hole 30b of the curved plates 26a, 26b. 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 39c having a large diameter or increase the number of balls 39c. As a result, the load capacity can be improved without changing the overall size of the rolling bearing 39, 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 26a and 26b of the deceleration portion B are provided with 180 ° phase shifts. 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 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 output 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, 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 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 embodiment, the outer raceway surfaces 33a and 33b of the wheel hub bearing 33 are formed on the outer member 22a, and the inner raceway surfaces 33c and 33d are formed on the wheel side rotation member 28 and the wheel hub 32. However, the present invention is not limited to this, and any form can be adopted. For example, an outer raceway surface may be formed on the outer ring fitted to the casing, and an inner raceway surface may be provided on the inner race fitted to the wheel-side rotating member or the wheel hub.

  Further, in the above embodiment, an example in which an angular ball bearing is adopted as the wheel hub bearing 33 is shown. However, the present invention is not limited to this, and examples thereof include a cylindrical roller bearing, a tapered roller bearing, a needle roller bearing, and an automatic adjustment. Regardless of whether the rolling element is a roller or a ball, such as a center 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.

  Moreover, although the electric vehicle 11 shown in FIG. 4 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 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 schematic sectional drawing of the in-wheel motor drive device concerning 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 a top view of the electric vehicle which has the in-wheel motor drive device of FIG. FIG. 5 is a rear sectional view of the electric vehicle of FIG. 4. It is the schematic of an axial gap motor.

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 In-wheel motor drive device, 22, 42 Casing, 22a Outer member, 23, 43 Stator, 24, 44 Rotor 24a, 28a, 32b Flange part, 24b, 28b, 32a Hollow part, 44a Outer diameter part, 25, 45 Motor side rotating member, 25a, 25b Eccentric part, 26a, 26b Curved plate, 27 Outer pin, 27a, 31a Needle Roller bearing, 28 wheel side rotating member, 29 counter weight, 30a, 30b through hole, 31 inner pin, 32d, 33g, 34, 36 sealing member, 33 wheel hub bearing, 33a first outer raceway surface, 33b second outer side Raceway surface, 33c first inner raceway surface, 33d second inner raceway surface, 33e, 39c Ball, 33f Cage, 35, 37, 38, 39 Rolling bearing, 39a Inner ring, 39b Outer ring, 22b Bolt, 40 Plastic joint, 41 Axial gap motor.

Claims (1)

A casing,
A motor unit that rotationally drives a motor side rotating member having an eccentric part;
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,
The motor part is
A stator fixed to the casing;
A radial gap motor including a rotor fixedly connected to the motor-side rotation member and disposed at a position facing the stator with a radial gap therebetween;
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.
An in-wheel motor drive device comprising: a motion conversion mechanism that converts the rotational motion of the revolving member into a rotational motion centered on the rotational axis of the motor-side rotating member and transmits the rotational motion to the wheel-side rotating member.

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