JP2013228105A - In-wheel motor drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reduction gear which is light in weight, excellent in durability, high in reliability and can obtain a high reduction gear ratio.SOLUTION: An in-wheel motor drive unit 21 comprises a casing 22, a motor A, and a speed reducing part B. The speed reducing part B includes: curved plates 26a, 26b which perform revolutionary movement accompanied by the rotation of a motor-side rotating member 25 with its rotation axis as a center; an outer pin 27 which is rotatably supported to the casing 22 by a needle rolling bearing 27c, and generates the rotation movement of the curved plates 26a, 26b by being engaged with external peripheries of the curved plates 26a, 26b; and a motion conversion mechanism which converts the rotation movement of the curve plates 26a, 26b to turning movement with a rotational axial core of the motor-side rotating member 25 as a center, and transmits it to a wheel-side rotating member 28.

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.

  Further, as a reduction gear for an electric vehicle, there is one in which a planetary gear reduction gear is incorporated as a reduction gear 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 second stage planetary gear speed reducer The 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 a reduction gear that is small, lightweight, excellent in durability, highly reliable, and capable of realizing a high reduction ratio.

  The present invention relates to a motor unit having a motor-side rotating member, a speed reducing unit having an output shaft that decelerates rotation of the motor-side rotating member and outputs it to an output shaft, and a wheel hub that transmits output from the output shaft to driving wheels In the in-wheel motor drive device including the bearing portion, the speed reduction portion is an eccentric portion provided in the motor-side rotation member, and is rotatably held by the eccentric portion, and the rotation shaft thereof is rotated with the rotation of the motor-side rotation member. A revolving member that revolves around the center, an outer periphery engaging member that engages with the outer peripheral portion of the revolving member to cause the revolving member to rotate, and the revolving member rotates to rotate the motor side rotating member. And a motion conversion mechanism that converts the rotational motion about the axis to the output shaft.

  The eccentric part includes a first eccentric part and a second eccentric part arranged in a phase in which centrifugal force due to the eccentric motion cancels each other, and the revolution member is a first revolution member that is rotatably held by the first eccentric part. And a second revolving member having the same outer peripheral shape as the first revolving member and rotatably held by the second eccentric portion. The first and second revolving members have a plurality of corrugations on their outer peripheral portions, and the outer peripheral engaging members are disposed on the revolving tracks of the first and second revolving members, and contact the outer peripheral portions of both revolving members. An outer pin is provided, and both ends of the outer pin are rotatably supported via needle roller bearings.

  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. Further, by making the outer periphery engaging member rotatable, it is possible to obtain a small in-wheel motor drive device having a large transmission torque.

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. FIG. 2 is an enlarged view of the periphery of an outer periphery engaging member in FIG. 1. It is an enlarged view of the outer periphery engaging member as a comparative example of FIG. It is a top view of the electric vehicle which has the in-wheel motor drive device of FIG. FIG. 7 is a rear sectional view of the electric vehicle of FIG. 6.

  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.

  Referring to FIG. 6, 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. 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, an in-wheel motor drive device 21 according to an embodiment of the present invention as shown in FIG.

  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 in FIG. FIG. 5 is an enlarged view of the outer peripheral engagement member.

  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 (reduction gear) that decelerates and outputs the rotation of the motor unit A, and a deceleration unit B. A wheel hub bearing C for transmitting the output from the drive wheel 14 to the drive wheel 14. The motor part A and the speed reduction part B are housed in the casing 22 and are mounted in the wheel housing 12a of the electric vehicle 11 as shown in FIG. It is done.

  The motor unit 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 an axial clearance, and a rotor 24 fixedly connected to the inner side of the rotor 24. This is an axial gap motor including a motor-side rotating member (input shaft) 25 that rotates integrally. 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 rotating member 25 is disposed from the motor part A through the speed reducing part B to the hollow part 28b of the wheel side rotating member (output shaft) 28, and has eccentric parts 25a and 25b in the speed reducing 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 speed reduction part B is rotatably supported with respect to the casing 22 by curved plates 26a, 26b as revolving members held rotatably by the eccentric parts 25a, 25b, and needle roller bearings 27c, and the curved plates 26a, 26b. A plurality of outer pins 27 as outer peripheral engagement members that engage with the outer peripheral portion of the motor, a motion conversion mechanism that transmits the rotational motion of the curved plates 26a and 26b to the wheel-side rotating member 28, and an attachment adjacent to the curved plate 26a. The first counterweight 29a and the second counterweight 29b attached adjacent to the curved plate 26b are provided.

  The wheel side rotation member 28 has a flange portion 28a and a cylindrical hollow portion 28b. The end face 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. The outer diameter surface of the hollow portion 28b is fitted with the inner diameter surface of the wheel hub 32, and the inner diameter surface of the hollow portion 28b is formed by the rotation axis of the motor side rotation member 25 and the rotation axis of the wheel side rotation member 28. The motor side rotation member 25 is rotatably supported by the rolling bearing 38 so as to coincide with each other.

  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 arranged 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.

  The outer pin 27 will be described in detail with reference to FIGS. 4 and 5. 4 is an enlarged view around the outer pin 27 shown in FIG. 1, and FIG. 5 is an enlarged view around the outer pin 47 as a comparative example of FIG.

  First, referring to FIG. 4, the outer pin 27 includes a large-diameter portion 27a having a relatively large diameter at the center, a small-diameter portion 27b having a relatively small diameter at both ends, a large-diameter portion 27a, and a small-diameter portion. 27b is a rod-shaped member including a tapered portion 27d. The large-diameter portion 27a is disposed at a position in contact with the curved plates 26a and 26b, and both are in direct contact. The small diameter portion 27b is rotatably supported by the casing 22 by a needle roller bearing 27c. Thus, by making the outer pin 27 rotatable to the casing 22, the contact resistance due to the engagement with the curved plates 26a and 26b can be reduced.

  Next, referring to FIG. 5, as a comparative example of the outer pin 27, both ends are fixed to the casing 42, and an outer pin 47 in which a needle roller bearing 47c is arranged in the central portion in contact with the curved plates 46a and 46b. The contact resistance between the curved plates 46a and 46b and the outer pin 47 can be reduced.

  4 and 5, a load (bending stress) is applied to the outer pins 27, 47 supported at both ends in the normal direction of the contact portions with the curved plates 26a, 26b, 46a, 46b. Therefore, it is desirable to increase the diameter of the outer pins 27 and 47 in order to ensure a sufficient maximum bending stress of the outer pins 27 and 47. However, the diameter of the region in contact with the curved plates 26a, 26b, 46a, 46b (the diameter d1 of the large diameter portion 27a in FIG. 4 and the diameter d2 including the needle roller bearing 47c in FIG. 5) is the curved plate. It is limited to the size of 26a, 26b, 46a, 46b and cannot be set freely.

  That is, if the curved plates 26a, 26b, 46a, 46b are the same size, the diameter d1 of the large diameter portion of the outer pin 27 shown in FIG. 4 and the needle roller bearing 47c of the outer pin 47 shown in FIG. The diameter d2 is the same size (d1 = d2). Then, the diameter d1 of the outer pin 27 shown in FIG. 4 can be set larger than the diameter d3 of the outer pin 47 shown in FIG. 5 (d1> d3). As a result, the outer pin 27 in direct contact with the curved plates 26a and 26b shown in FIG. 4 can increase the maximum bending stress as compared with the outer pin 47 shown in FIG.

  In order to obtain the effect of the present invention, the large diameter portion 27a and the small diameter portion 27b in FIG. 4 may have the same diameter. However, as the diameter of the small diameter portion 27b increases, the needle roller bearing 27c that supports the outer pin 27 also increases in size. As a result, there is a problem that a space for accommodating the needle roller bearing 27c of the casing 22 is also increased. Therefore, the diameter of the large-diameter portion 27a in contact with the curved plates 26a, 26b is increased to ensure a sufficient maximum bending stress, and the diameter of the small-diameter portion 27b supported by the needle roller bearing 27c is decreased to accommodate the bearing. Reduce space. As a result, the in-wheel motor drive device 21 that is small and has a large transmission torque can be obtained.

  In the above embodiment, the example in which the needle roller bearing 27c is used as the bearing for supporting the outer pin 27 is shown, but the present invention is not limited to this, and any other bearing can be adopted. However, by employing the needle roller bearing 27c, the bearing housing space can be further reduced.

  Further, a vertical stepped portion may be provided between the large diameter portion 27a and the small diameter portion 27b. However, in order to reduce the stress concentration on the boundary portion, as shown in FIG. It is desirable to provide a tapered portion 27d.

  The first and second counterweights 29a and 29b are disk-shaped and have a through-hole that receives the motor-side rotating member 25 at a position deviated from the center of the first and second counterweights 29a and 29b, and counteract the couple generated by the rotation of the curved plates 26a and 26b. For this reason, it is arranged adjacent to the outer side of each eccentric part 25a, 25b with a 180 ° phase change from the eccentric part.

  Here, as shown in FIG. 3, the curved plates 26a and 26b and the first and second counterweights 29a and 29b have a central point G between the two curved plates 26a and 26b, and the central point G and the curved line. The distance between the centers of the plates 26a and 26b is L1, the distance between the center point G and the centers of the first and second counterweights 29a and 29b is L2, and the mass of the curved plates 26a and 26b. M1, the mass of the first and second counterweights 29a, 29b is m2, the amount of eccentricity of the center of gravity of the curved plates 26a, 26b from the rotational axis is ε1, and the center of gravity of the first and second counterweights 29a, 29b When the amount of eccentricity from the rotation axis is ε2, 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.

  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.

  In the above embodiment, the motor-side rotating member 25 is supported by interposing the rolling bearing 38 in the hollow portion 28b of the wheel-side rotating member 28. However, a part of the wheel hub 32 is used as the wheel-side rotating member 28. In this case, a rolling bearing is disposed in the hollow portion 32a of the wheel hub 32 to support the motor-side rotating member 25. Become.

  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, and only the rotational motion of the curved plates 26 a and 26 b is transmitted to the wheel hub 32 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.

  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.

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, since the outer pin 27 is rotatable on the casing 22 and the needle roller bearing 31a is provided at a position where the outer pin 27 contacts the curved plates 26a and 26b of the inner pin 31, the contact resistance is reduced. Transmission efficiency is improved.

  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 with respect to the casing 22, 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.

  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.

  In the above embodiment, the wheel-side rotating member 28 and the wheel hub 32 are fixedly connected by expanding and caulking. However, the present invention is not limited to this. Also good.

  In the above-described embodiment, an example in which an angular ball bearing is adopted as the wheel hub bearing 33 has been shown. 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 bearing. Spherical roller bearings, deep groove ball bearings, angular contact ball bearings, 4-point contact ball bearings, etc., regardless of whether the rolling element is a roller or a ball, whether it is a plain bearing or a rolling bearing In addition, 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.

  In the above-described embodiment, an example in which an axial gap motor is employed for 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 a radial gap motor including a stator fixed to the casing and a rotor disposed at a position facing the stator with a radial gap inside.

  Furthermore, although the electric vehicle 11 shown in FIG. 6 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.

  The present invention provides a reduction gear that is small, lightweight, excellent in durability, high in reliability, and capable of realizing a high reduction ratio, and is advantageously applied to the machine industry field.

  DESCRIPTION OF SYMBOLS 11 Electric vehicle, 12 Chassis, 12a Wheel housing, 12b Suspension device, 13 Front wheel, 14 Rear wheel (drive wheel), 15, 21 In-wheel motor drive device, 22 Casing, 22a Outer member, 23 Stator, 24 Rotor, 24a , 28a, 32b Flange part, 24b, 28b, 32a Hollow part, 25 Motor side rotating member (input shaft), 25a, 25b Eccentric part, 26a, 26b, 46a, 46b Curved plate, 27, 47 Outer pin, 27a Large diameter Part, 27b small diameter part, 27c, 31a, 47c needle roller bearing, 27d taper part, 28 wheel side rotating member (output shaft), 29a, 29b counterweight, 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 raceway surface, The first inner raceway surface 3c, 33d second inner raceway surface, 33e, 39c ball, 33f cage, 35,37,38,39,41 rolling, 39a inner, 39 b outer, 22b volts, 40 plastic coupling portion.

Claims (1)

A motor unit having a motor side rotating member, a speed reducing unit having an output shaft and decelerating the rotation of the motor side rotating member and outputting it to the output shaft, and a wheel hub bearing for transmitting the output from the output shaft to the drive wheels An in-wheel motor drive device comprising:
The deceleration part is
An eccentric portion provided on the motor side rotating member;
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 periphery engaging member that engages with an outer peripheral portion of the revolving member to cause rotation of the revolving member;
A rotation conversion mechanism for converting the rotation motion of the revolving member into a rotation motion centered on the rotation axis of the motor side rotation member and transmitting it to the output shaft;
The eccentric portion is
Including a first eccentric portion and a second eccentric portion arranged in a phase that cancels out centrifugal force due to eccentric motion,
The revolving member is
A first revolving member rotatably held by the first eccentric portion;
A second revolving member having the same outer peripheral shape as the first revolving member and rotatably held by the second eccentric part,
The first and second revolving members have a plurality of waveforms on the outer periphery thereof,
The outer periphery engaging member is disposed on the revolving track of the first and second revolving members, and includes an outer pin that comes into contact with the outer peripheral portions of both revolving members,
The outer pin is an in-wheel motor drive device in which both end portions thereof are rotatably supported via needle roller bearings.

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