JP2012176715A - In-wheel motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain sufficient durability even if a housing which is formed using light metal such as an aluminum alloy of a motor and a reduction part of an in-wheel motor unit are fastened to fixing members on a vehicle body side with bolts, and in addition, to reduce thicknesses of bolt-fastened portions to minimum levels.SOLUTION: A male member 61 or a female member 62 which forms a fastening bolt member is formed using an iron material, and one of the male member 61 and the female member 62 is inserted into the housing 22b.

Description

  The present invention relates to an in-wheel motor drive device.

  A conventional in-wheel motor drive device is described in, for example, Japanese Patent Application Laid-Open No. 2008-132941 (Patent Document 1).

The in-wheel motor drive device needs to be fastened to the suspension part of the vehicle body or the fixing member on the vehicle body by some method.
In the in-wheel motor drive device disclosed in Patent Document 1, a component formed integrally with a housing of a motor unit or a housing of a speed reduction unit, or a retrofitted component, and a suspension of a vehicle body are fastened.
By the way, the in-wheel motor drive device 101 shown in FIG. 11 includes a motor unit 103 that rotationally drives the motor-side rotation member 106, and a reduction unit that decelerates the rotation of the motor-side rotation member 106 and transmits it to the wheel-side rotation member 108. 105, and a wheel hub bearing portion 104 having a wheel hub 109 fixedly connected to the wheel side rotating member 108.

  As described above, the in-wheel motor drive device 101 having the above-described configuration needs to fasten the housing 110 of the motor unit 103 and the speed reduction unit 105 and the suspension unit 111 on the vehicle body side by some method.

  In the example of FIG. 11, the upper suspension part 111 on the vehicle body side and the housing 110 of the speed reduction part 105 are fastened with bolts 112, and the lower suspension part 112 on the car body side and the housing 110 of the speed reduction part 105 and bolts 114 are fastened. Yes.

JP 2008-132941 A

  By the way, as described above, in the in-wheel motor drive device 101, it is necessary to fasten the housing of the motor unit 103 or the speed reduction unit 105 and the member on the vehicle body by some method. Since the housing 107 of the part 103 and the speed reduction part 105 is usually formed of an aluminum alloy for weight reduction, a screw hole for fastening a bolt is set longer than a steel material from the viewpoint of securing strength. There is a need.

  For this reason, there existed a problem that the whole physique of an in-wheel motor drive device became large and the weight increased.

  Also, once the in-wheel motor drive device is attached to the vehicle body, there are few opportunities to remove it, but if the screw hole is damaged, it will be necessary to replace the entire housing, so a screw hole should be formed in the light metal housing itself. Is not preferable in terms of durability.

  Therefore, the present invention can provide sufficient durability even if the motor part and the housing of the speed reduction part of the in-wheel motor driving device formed of a light metal such as an aluminum alloy and the fixing member on the vehicle body are bolted. In addition, it is an object to minimize the wall thickness of the bolt fastening portion.

  In order to solve the above-mentioned problems, the present invention has a driving device for generating a driving force of a wheel in the wheel, the housing of the driving device is made of light metal, and the housing and a fixing member on the vehicle body side In an in-wheel motor drive device that is fastened by a bolt fastening member, a male member or a female member that constitutes the bolt fastening member is formed of an iron material, and one of the male member or the female member is disposed in the housing. Features.

  The male member or female member formed of the iron material is preferably inserted by casting when the housing is cast.

  As the casting material for the housing, an aluminum-based alloy can be used.

  The male member or the female member arranged in the housing is preferably provided with a retaining means or a rotation preventing means for the housing so that the male member or the female member is not pulled out or rotated together when the bolt is fastened.

  The male member or the female member arranged in the housing may be formed as a ring-shaped member integrated in the circumferential direction.

  The ring-shaped member can be a cast or a pressed product.

  The thread portion formed on the male member or the female member may be processed before casting or may be processed after casting.

  The female member can be constituted by a nut, particularly a cap nut.

  The male member can be composed of a bolt.

  The bolt may be formed by casting a shaft member in the housing and then screwing it.

  As described above, since the male member or the female member made of the iron material constituting the bolt fastening member is arranged in the light metal housing as described above, the durability at the time of bolt fastening is good, and the bolt fastening The thickness of the part can also be minimized.

It is a schematic sectional drawing of the in-wheel motor drive device concerning one Embodiment of this invention. It is an enlarged view of the bolt fastening part of FIG. (A) is a front view of the female member which comprises the bolt fastening member cast in the housing of FIG. 1, (b) is the vertical side view. It is an enlarged view of the bolt fastening part of the in-wheel motor drive which concerns on other embodiment of this invention. It is a longitudinal cross-sectional view of the ring member which integrated the female member which comprises the bolt fastening member of FIG. 4 in the circumferential direction. It is an enlarged view of the bolt fastening part of embodiment which uses a cap nut as a female member which comprises the bolt fastening member cast by the housing. It is an enlarged view of the bolt fastening part of embodiment using a bolt as a male member which constitutes a bolt fastening member cast into a housing. It is sectional drawing of the deceleration part of FIG. It is a schematic plan view of the electric vehicle which has the in-wheel motor drive device of FIG. It is the figure seen from the electric vehicle back of FIG. It is a schematic sectional drawing of the conventional in-wheel motor drive device.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 9, an electric vehicle 11 having an in-wheel motor drive device according to an embodiment of the present invention includes a chassis 12, a front wheel 13 as a steering wheel, a rear wheel 14 as a drive wheel, And an in-wheel motor drive device 21 that transmits drive force to each of the rear wheels 14. As shown in FIG. 10, the rear wheel 14 is housed 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 21 for driving the left and right rear wheels 14 inside the wheel housing 12a. This eliminates the need to secure a wide cabin space and control the rotation of the left and right drive wheels.

  On the other hand, in order to improve the running stability of the electric vehicle 11, it is necessary to suppress the unsprung weight. Further, in order to secure a wider cabin space, the in-wheel motor drive device 21 is required to be smaller and lighter.

  As shown in FIG. 1, the 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 as driving wheels. 14, the motor hub A and the speed reducer B are housed in the motor housing 22a and the speed reducer housing 22b, and are installed in the wheel housing 12a of the electric vehicle 11 as shown in FIG. Attached to.

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

  The motor side rotation member 25 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 25a and 25b in the speed reduction part B. The motor-side rotating member 25 is fitted and fixed to the hollow portion 24 b of the rotor 24 and rotates integrally with the rotor 24. Further, the two eccentric portions 25a and 25b are provided with a 180 ° phase change in order to cancel out the centrifugal force due to the eccentric motion.

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

  The wheel side rotation member 28 includes a flange portion 28a and a shaft portion 28b. Holes for fixing the inner pins 31 are formed on the end face of the flange portion 28a at equal intervals on the circumference around the rotation axis of the wheel side rotation member 28. Further, the shaft portion 28 b is fitted and fixed to the hub wheel 32 and transmits the output of the speed reduction portion B to the wheel 14. The flange portion 28a of the wheel side rotation member 28 and the motor side rotation member 25 are rotatably supported by a rolling bearing 36c.

  As shown in FIG. 8, the curved plates 26 a and 26 b have a plurality of corrugations composed of trochoidal curves such as epitrochoids on the outer periphery, and a plurality of through holes 30 a 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 centering on the rotation axis of the curved plates 26a, 26b, and receive inner pins 31 described later. Further, the through hole 30b is provided at the center of the curved plates 26a and 26b and is fitted to the eccentric portions 25a and 25b.

  The curved plates 26a and 26b are supported by the rolling bearing 41 so as to be rotatable with respect to the eccentric portions 25a and 25b. The rolling bearing 41 is directly formed on the inner ring member having an inner raceway surface on the outer diameter surface of the eccentric portions 25a and 25b and the inner diameter surface of the through hole 30b of the curved plates 26a and 26b. A cylindrical roller bearing comprising an outer raceway surface, a plurality of cylindrical rollers 44 disposed between the inner raceway surface and the outer raceway surface, and a retainer (not shown) that holds the spacing between adjacent cylindrical rollers 44. .

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

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

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

  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 indicates the outer diameter dimension of the inner pin 31 ("maximum outer diameter including needle roller bearing"). It is set larger by a predetermined amount than the same).

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

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

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

  Further, the speed reduction unit lubrication mechanism further includes a cooling means for cooling the lubricating oil passing through the circulating oil passage 22g. The cooling means in this embodiment includes a cooling water passage 22e provided in the motor part housing 22b, and the cooling means contributes not only to lubricating oil but also to the cooling of the motor part A.

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

  In the hub wheel 32, a wheel mounting flange 32b is integrally formed on the outer surface of the hollow portion 32a. An outer raceway surface is integrally formed on the outer diameter surface of the hollow portion 32a on the outer side of the vehicle, and an inner ring 32c having an inner raceway surface on the outer surface is fitted to the outer diameter surface of the hollow portion 32a on the inner side of the vehicle. is doing.

  The fixed ring 33 has an outer raceway surface and an inner raceway surface facing the outer raceway surface and the inner raceway surface of the hub wheel 32 on the inner peripheral surface, and a fixing flange 33a on the outer peripheral surface.

  Double rows of balls 34 are accommodated between the outer raceway surface and the inner raceway surface of the hub wheel 32 and the fixed ring 33 facing each other.

  The fixing flange 33 a of the fixed wheel 33 and the speed reduction unit housing 22 b are fastened by a bolt 37.

  The speed reduction unit housing 22b is bolted to a fixing member 70 on the vehicle body side of the suspension device 12b. The fixing member 70 on the vehicle body side is provided at each of an upper part and a lower part of the suspension device 12b.

  The bolt fastening member is constituted by a male member 61 and a female member 62 formed of an iron material. In the embodiment of FIGS. 1 and 2, a bolt is adopted as the male member 61, and the bolt is formed on the fixing member 70. The bolt is inserted into the bolt insertion hole, and the end of the bolt is screwed into the female member 62 disposed in the speed reduction portion housing 22b, thereby fastening the fixing member 70 and the speed reduction portion housing 22b.

  As shown in FIG. 3, the female member 62 employed in the embodiment of FIGS. 1 and 2 includes a cylindrical portion 62a having a screw hole and a flange portion 62b formed on the outer periphery of the end portion of the cylindrical portion 62a. Thus, when the speed reduction part housing 22b is cast from an aluminum alloy, it is inserted into the speed reduction part housing 22b by casting.

  The female member 62 shown in FIG. 3 has a flange portion 62b formed on the outer periphery of the end portion of the cylindrical portion 62a so as not to come out in the axial direction when the bolt is fastened. Further, the outer shape of the cylindrical portion 62a of the female member 62 is not a simple cylinder but a D shape so as not to rotate together when the bolt is fastened.

  As a means for preventing rotation at the time of bolt fastening, for example, a petal shape or an elliptical shape can be used in addition to the D shape. Further, the outer shape may be knurled, or a step may be provided in the axial direction as a retaining means when fastening the bolt.

  The female member 62 may be arranged in the speed reduction unit housing 22b in the same number as the bolts corresponding to the number of bolts. However, as shown in FIGS. The screw hole 64 may be formed in the ring-shaped member 63 by being inserted into the housing 22b.

  By casting the ring-shaped member 63 into the housing 22b, the rigidity of the housing 22b is increased, and the change in the internal clearance when a load is applied can be suppressed to a small level. .

  Next, the embodiment of FIG. 6 is an example in which an iron cap nut is used as the female member 62.

  In the embodiment of FIG. 7, an iron bolt is used as the male member 61, the head portion of this bolt is inserted into the speed reduction unit housing 22 b, and a nut as the female member 62 is disposed on the fixing member 70. Show.

  In the embodiment in which the bolt is inserted into the speed reduction unit housing 22b, a shaft member that is not threaded may be inserted at the time of casting, and the shaft member may be threaded after the insertion.

Hereinafter, the operation principle of the in-wheel motor drive device 21 will be described.
The motor unit A receives, for example, electromagnetic force generated by supplying an alternating current to the coil of the stator 23, and the rotor 24 composed of a permanent magnet or a magnetic material rotates. Thereby, when the motor side rotation member 25 connected to the rotor 24 rotates, the curved plates 26 a and 26 b revolve around the rotation axis of the motor side rotation member 25. At this time, the outer pin 27 engages with the curved waveform of the curved plates 26 a and 26 b to cause the curved plates 26 a and 26 b to rotate in the direction opposite to the rotation of the motor-side rotating member 25.

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

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

  Note that the reduction ratio of the speed reduction unit B having the above-described configuration is calculated as (ZA−ZB) / ZB, where ZA is the number of outer pins 27 and ZB is the number of waveforms of the curved plates 26a and 26b. In the embodiment shown in FIG. 8, since ZA = 12, ZB = 11, the reduction ratio is 1/11, and a very large reduction ratio can be obtained.

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

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

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

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

  In addition, although the motion conversion mechanism in the above-described embodiment has been shown as an example including the inner pin 31 fixed to the wheel side rotation member 28 and the through hole 30a provided in the curved plates 26a and 26b, Without being limited to the above, it is possible to adopt an arbitrary configuration capable of transmitting the rotation of the speed reduction unit B to the wheel hub 32. For example, it may be a motion conversion mechanism composed of an inner pin fixed to a curved plate and a hole formed in the wheel side rotation member.

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

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

  In each of the above-described embodiments, an example in which a radial gap motor is adopted as the motor unit A has been described. However, the present invention is not limited to this, and a motor having an arbitrary configuration can be applied. For example, it may be an axial gap motor including a stator fixed to the housing and a rotor disposed at a position facing the inner side of the stator with a gap in the axial direction.

  Moreover, in each said embodiment, although the example of the in-wheel motor drive device 21 which employ | adopted the cycloid deceleration mechanism as the deceleration part B was shown, it is not restricted to this, Arbitrary deceleration mechanisms can be employ | adopted. For example, a planetary gear reduction mechanism, a parallel shaft gear reduction mechanism, or the like is applicable. Moreover, this invention is applicable also in the in-wheel motor unit (motor direct drive) without a reduction gear.

  Furthermore, although the electric vehicle 11 shown in FIG. 9 has shown the example which used the rear wheel 14 as the driving wheel, it is not restricted to this, The front wheel 13 may be used as a driving wheel and may be a four-wheel driving vehicle. . In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and should be understood as including, for example, a hybrid vehicle.

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

21 In-wheel motor drive device A Motor part B Deceleration part C Wheel hub bearing part 22 Housing 22a Motor housing 22b Reduction part housing 32 Hub wheel 33 Fixed wheel 61 Male member 62 Female member 62a Tube part 62b Flange part 63 Ring-shaped member 64 Screw Hole 70 fixing member

Claims (12)

  An in-wheel motor drive device having a drive device for generating wheel drive force in the wheel, wherein the housing of the drive device is made of light metal, and the housing and a fixing member on the vehicle body side are fastened by a bolt fastening member. The in-wheel motor drive device according to claim 1, wherein a male member or a female member constituting the bolt fastening member is formed of an iron material, and one of the male member or the female member is disposed in the housing.   2. The in-wheel motor drive device according to claim 1, wherein the housing is made of a casting, and one of a male member and a female member constituting the bolt fastening member is inserted when the housing is cast.   The in-wheel motor drive device according to claim 1 or 2, wherein the casting of the housing is an aluminum alloy.   The in-wheel motor drive device according to any one of claims 1 to 3, wherein a male member or a female member arranged in the housing is provided with a retaining or rotation preventing means for the housing.   The in-wheel motor drive device in any one of Claims 1-4 in which the male member or female member arrange | positioned at the said housing is formed in the ring-shaped member integrated in the circumferential direction.   The in-wheel motor drive device according to claim 5, wherein the ring-shaped member is a casting or a press-processed product.   An in-wheel motor drive device, wherein a thread portion formed on the male member or the female member according to claim 1 is processed after casting.   The in-wheel motor drive device according to claim 1, wherein the female member is a nut.   The in-wheel motor drive device whose said nut of Claim 8 is a cap nut.   The in-wheel motor drive device according to claim 1, wherein the male member is a bolt.   The in-wheel motor drive device according to claim 10, wherein a thread portion of the bolt is formed by post-processing on a cylindrical member cast into the housing.   A vehicle provided with the in-wheel motor drive device of Claims 1-11.

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