JP2008189212A - In-wheel motor driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-wheel motor driving device for improving maintainability by facilitating disassembling and assembling work, and attaining reliability and maneuvering stability by eliminating looseness in the peripheral direction of a connecting section. <P>SOLUTION: In this in-wheel motor driving device, a bearing device C for a wheel has an outer member 22 joined to a speed reduction part B via a connecting member 11 and forming an outside rolling traveling surface 22a of double rows on the inner periphery, a hub wheel 25 having integrally a wheel installing flange 26 in one end part and forming an inside rolling traveling surface 25a and a small diameter step part 25b on the outer periphery, an inner member 24 fitted to the small diameter step part 25b and composed of an inner ring 27 forming an inside rolling traveling surface 27a on the outer periphery, and a rolling body 23 of double rows stored between both members, and is separably joined to the connecting member 11. This joining part is composed of a fitting profile 28 forming a plurality of projecting teeth 28a on the outer periphery of a shaft part 17 of the connecting member 11, and a fitting profile 30 forming a cross-sectional dovetail groove-shaped recessed groove 30a on the inner periphery of the hub wheel 25. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an in-wheel motor drive device used in a vehicle having a direct drive wheel as a drive wheel, such as an automobile, and more particularly, an output shaft of an electric motor and a wheel hub are coaxially connected via a reduction gear. The present invention relates to an in-wheel motor drive device.

  In recent years, in-wheel motor systems in which a motor is built in a wheel are being adopted in a vehicle driven by a motor such as an electric vehicle. Here, the conventional in-wheel motor drive device 50 is described in Unexamined-Japanese-Patent No. 2006-258289 (patent document 1), for example. As shown in FIG. 10, the in-wheel motor driving device 50 includes a motor unit 53 that generates a driving force inside a casing 52 that is attached to a vehicle body 51, a wheel bearing device 55 to which a wheel 54 is attached, and a motor unit. And a speed reducer 57 that decelerates the rotation of 53 and transmits it to the hub wheel 56 of the wheel bearing device 55.

  Here, in order to reduce the weight and size of the apparatus, a low torque and high rotation motor is adopted for the motor unit 53 and a large torque is required to drive the wheels 54. A cycloid reducer that is compact and provides a high reduction ratio is employed.

  The speed reducer 57 includes a motor-side rotating member 58 having eccentric portions 58a and 58b, curved plates 59a and 59b disposed on the eccentric portions 58a and 58b, and curved plates 59a and 59b with respect to the motor-side rotating member 58. Rolling bearings 60a, 60b that are rotatably supported, a plurality of outer pins 61 that engage with the outer peripheral surfaces of the curved plates 59a, 59b and cause the curved plates 59a, 59b to rotate, and the curved plates 59a, 59b. A plurality of inner pins 63 that transmit the rotation motion to the inner member (wheel-side rotating member) 62 are provided.

Further, the wheel bearing device 55 is integrally provided with an outer flange 64b integrally attached to the casing 52 on the outer periphery, and the double-row outer rolling surfaces 64a and 64a are integrally formed on the inner periphery. A wheel mounting flange 67 for attaching the wheel 54 to one end, and an inner rolling surface 56a facing one of the double row outer rolling surfaces 64a, 64a on the outer periphery, and the inner rolling surface. A hub wheel 56 formed with a cylindrical small-diameter step 56b extending in the axial direction from 56a, and the other of the double-row outer rolling surfaces 64a and 64a are press-fitted and fixed to the small-diameter step 56b of the hub wheel 56 An inner member 62 formed of an inner ring 65 formed with an inner rolling surface 65a opposite to the inner ring 65, and a double row of balls accommodated in a freely rolling manner between the rolling surfaces of the inner member 62 and the outer member 64 66.
JP 2006-258289 A

  However, in such a conventional in-wheel motor drive device 50, since the wheel bearing device 55 and the speed reduction portion 57 are fixed integrally, for example, disassembly work in the repair market is difficult, and there is a problem in terms of maintainability. there were.

  The present invention has been made in view of such a conventional problem, and facilitates disassembly / assembly work to improve maintainability, and eliminates the play in the circumferential direction of the connecting portion to improve reliability and steering stability. Another object of the present invention is to provide an in-wheel motor drive device.

In order to achieve such an object, the invention according to claim 1 of the present invention includes a casing, and a motor portion that is disposed in the casing and that rotationally drives a motor-side rotating member that is integrally formed with an eccentric portion. An in-wheel motor drive device comprising: a speed reduction portion that reduces the rotation of the motor side rotation member; and a wheel bearing device that is connected to the speed reduction portion so as to transmit torque and rotatably supports the wheel. A bearing device for a vehicle is coupled to the speed reduction part via a connecting member, and the wheel bearing device has an attachment flange for attaching to the casing on the outer periphery, and a double row outer rolling surface on the inner periphery. Is formed integrally with an outer member, a wheel attachment flange for attaching a wheel to one end, and a hub wheel formed with a cylindrical small-diameter stepped portion extending in the axial direction on the outer periphery, and the hub ring An inner member formed of at least one inner ring press-fitted into a small-diameter step portion, and formed with a double row inner rolling surface facing the double row outer rolling surface, the inner member and the outer member At least the outer opening of the annular space formed between the outer member and the inner member. And the connecting member integrally includes a flange portion extending radially outward and a shaft portion protruding in the axial direction from the flange portion, and the connecting member and the hub wheel. Are coupled in an axially separable manner via screw means,
The coupling portion corresponds to the fitting profile formed by arranging a plurality of convex teeth on the outer periphery of the shaft portion of the connecting member, and corresponds to the fitting profile, on the inner periphery of the hub wheel, to the convex teeth. A plurality of concave grooves having a cross-sectional dovetail shape to be engaged with each other, and the convex teeth are formed in a substantially trapezoidal cross section having a predetermined negative pressure angle. A predetermined inclination angle is formed in the axial direction with respect to the axial center.

  Thus, in the in-wheel motor drive device including the motor portion and the speed reduction portion disposed in the casing and the wheel bearing device connected to the speed reduction portion, the wheel bearing device is interposed via the connecting member. An outer member coupled to the speed reduction portion, the wheel bearing device integrally having a mounting flange for being attached to the casing on the outer periphery, and a double row outer rolling surface formed integrally on the inner periphery; A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end and having a cylindrical small-diameter step portion extending in the axial direction on the outer periphery, and at least one press-fitted into the small-diameter step portion of the hub ring An inner member composed of two inner rings and formed with a double-row inner rolling surface facing the double-row outer rolling surface, and freely rollable between both rolling surfaces of the inner member and the outer member. Housed double row rolling elements, outer member and inward A seal that is attached to at least an opening on the outer side of the opening of the annular space formed between the material and a flange that extends radially outward, and an axial direction from the flange The connecting member and the hub ring are coupled to each other in a separable manner in the axial direction via screw means, and the coupling portion is connected to the outer periphery of the shaft portion of the connecting member. A fitting profile formed by arranging a plurality of convex teeth, and a plurality of concave grooves having a cross-sectional dovetail shape engaging the convex teeth on the inner periphery of the hub wheel corresponding to the fitting profile. Because the convex teeth are formed in a substantially trapezoidal cross section having a predetermined negative pressure angle, and the tooth surface has a predetermined inclination angle in the axial direction with respect to the axial center. , Making disassembly and assembly easier and improving maintainability It is possible to provide an in-wheel motor drive device which attained steering stability and reliability by eliminating the circumferential backlash of the connecting portion.

  Preferably, as in the invention described in claim 2, the hub in a state where a predetermined bearing preload is applied by a crimping portion formed by plastically deforming an end portion of the small-diameter stepped portion radially outward. The inner ring is fixed in the axial direction with respect to the ring, and the coupling member and the hub ring are coupled so that a predetermined axial clearance is interposed between the shoulder portion of the coupling member and the end surface of the crimping portion. If this is done, it is possible to provide a self-retaining structure capable of maintaining the bearing preload for a long period of time without tightening the screw means firmly, and even if a large torque is applied to the connecting member, There is no slip noise.

  According to a third aspect of the present invention, a seal is attached to an opening of an annular space formed between the outer member and the inner member, the bearing portion is grease-lubricated, and the casing If an oil seal is attached to the outer end of the ring and the opening of the annular space formed between the casing and the connecting member is sealed, the bearing and the speed reducer are blocked by the oil seal, and the speed is reduced. This prevents the lubricating oil that lubricates the part from entering the bearing and prevents foreign matter such as metal wear powder that has entered the lubricating oil in the deceleration part from entering the bearing and reducing the peeling life. it can.

  Further, as in the invention described in claim 4, an inner rolling surface facing one of the double row outer rolling surfaces is directly formed on the outer periphery of the hub wheel, and an inner side base portion of the wheel mounting flange is formed. If the outer side seal has a side lip that is slidably in contact with the base and a grease lip that is inclined toward the inner side of the bearing, a compact seal with high sealing performance can be obtained. Therefore, the bearing span can be maximized, and the durability of the wheel bearing device can be improved.

  According to a fifth aspect of the present invention, the speed reduction portion has a plurality of waveforms formed of a trochoidal curve on an outer periphery, and a plurality of through holes that pass through the eccentric portion are formed. A curved plate that performs a revolving motion around its rotational axis as the side rotating member rotates, and a plurality of external members that are brought into rolling contact with the outer peripheral portion of the curved plate via needle roller bearings to generate a rotational motion. A pin, and an inner pin fixed to the flange portion of the connecting member and in rolling contact with the inner periphery of the through-hole via a needle roller bearing, and the rotation of the motor-side rotating member for rotating the curved plate If it is composed of a cycloid reduction mechanism that converts it into a rotational motion centered on the shaft and transmits it to the connecting member, an extremely large reduction ratio can be obtained even in a compact configuration without a multi-stage configuration. High rotation, low torque type Even when employing a data portion, it is possible to transmit sufficient torque to the wheels.

  An in-wheel motor drive device according to the present invention includes a casing, a motor unit that is disposed in the casing and that rotationally drives a motor-side rotating member integrally formed with an eccentric portion, and rotates the motor-side rotating member. An in-wheel motor drive device comprising a speed reducing portion and a wheel bearing device connected to the speed reducing portion so as to be able to transmit torque and rotatably supporting a wheel, wherein the wheel bearing device is connected via a connecting member. The outer member coupled to the speed reduction portion, the wheel bearing device integrally having a mounting flange to be attached to the casing on the outer periphery, and a double row outer rolling surface formed integrally on the inner periphery And a hub wheel having a wheel mounting flange for mounting the wheel at one end and a cylindrical small diameter step portion extending in the axial direction on the outer periphery, and press-fitting into the small diameter step portion of the hub ring An inner member formed with at least one inner ring and formed with a double-row inner rolling surface facing the double-row outer rolling surface, and both rolling surfaces of the inner member and the outer member. A double-row rolling element housed in a freely rollable manner, and a seal attached to at least the outer opening of the annular space formed between the outer member and the inner member; The connecting member integrally includes a flange portion extending radially outward and a shaft portion projecting in an axial direction from the flange portion, and the connecting member and the hub wheel are interposed via screw means. And the coupling portion corresponds to the fitting profile formed by arranging a plurality of convex teeth on the outer periphery of the shaft portion of the connecting member, and the fitting profile. On the inner periphery of the hub wheel, a plurality of concave grooves having a cross-sectional dovetail shape that engages with the convex teeth, etc. The convex teeth are formed in a substantially trapezoidal cross section having a predetermined negative pressure angle, and a predetermined inclination angle is formed in the axial direction with respect to the axial center on the tooth surface. As a result, disassembly and assembly work can be facilitated to improve maintainability, and an excessive pressure input is not required, and it is possible to easily obtain a strong fitting state with no circumferential play at the final stage of insertion. It is possible to prevent an unpleasant rattling sound from occurring for a long period of time. Further, it is possible to suppress the radially outward component force generated in the engaging portions of the convex teeth and the concave grooves during torque transmission, and the bearing clearance is not adversely affected by the expansion of the hub wheel.

  A casing, a motor unit disposed in the casing, and a motor-side rotating member integrally formed with an eccentric portion; a reduction unit that decelerates rotation of the motor-side rotating member; and a torque applied to the reduction unit An in-wheel motor drive device including a wheel bearing device that is coupled so as to be able to transmit and rotatably supports a wheel, wherein the wheel bearing device is coupled to the speed reduction unit via a coupling member, The apparatus has a mounting flange integrally attached to the casing on the outer periphery, an outer member integrally formed with a double row outer rolling surface on the inner periphery, and a wheel for mounting the wheel on one end. A hub having an integral mounting flange and formed on the outer periphery thereof with an inner rolling surface facing one of the double row outer rolling surfaces and a cylindrical small-diameter stepped portion extending in the axial direction from the inner rolling surface. Wheel, and An inner member formed of an inner ring press-fitted into a small-diameter step portion of the hub wheel and formed with an inner rolling surface facing the other of the double row outer rolling surfaces, and the inner member and the outer member. A double row rolling element accommodated between both rolling surfaces, and a seal attached to an opening of an annular space formed between the outer member and the inner member, The inner ring is fixed in the axial direction with respect to the hub ring in a state where a predetermined bearing preload is applied by a caulking portion formed by plastically deforming an end portion of the small-diameter stepped portion radially outward. The member integrally has a flange portion extending radially outward and a shaft portion protruding in the axial direction from the flange portion, and the connecting member and the hub wheel are separated in the axial direction via screw means. The coupling part is formed with a plurality of convex teeth arranged on the outer periphery of the shaft part of the connecting member. A fitting profile formed by arranging a plurality of dovetail grooves having a cross-sectional dovetail shape to be engaged with the convex teeth on the inner periphery of the hub wheel, corresponding to the fitting profile. The convex teeth are formed in a substantially trapezoidal cross section having a predetermined negative pressure angle, and a predetermined inclination angle is formed on the tooth surface in the axial direction with respect to the axial center.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing an embodiment of an in-wheel motor drive device according to the present invention, FIG. 2 is a transverse sectional view taken along line II-II in FIG. 1, and FIG. 3 is a main portion of FIG. FIG. 4 is an enlarged view of the main part showing the eccentric part of FIG. 1, FIG. 5 is an enlarged view of the wheel bearing device of FIG. 1, and FIG. 6 (a) is a view of the shaft part of the connecting member of FIG. The front view which shows a fitting profile, (b) is a cross-sectional view along the VI-VI line of (a), (c) is the shape when the pressure angle of the fitting profile is negative and when it is positive FIG. 7 (a) is a front view showing a manufacturing method of a fitting profile, FIG. 7 (b) is a cross-sectional view along the line VII-VII, and FIG. FIG. 9 is a graph showing the expansion amount of the hub wheel and the separation force generated in the engagement portion with respect to the inclination angle. A. In the following description, the side closer to the outer side of the vehicle in a state assembled to the vehicle is referred to as the outer side (left side in the drawing), and the side closer to the center is referred to as the inner side (right side in the drawing).

  The in-wheel motor drive device 1 transmits a motor unit A that generates a driving force, a deceleration unit B that decelerates and outputs rotation of the motor unit A, and an output from the deceleration unit B to wheels (not shown). Wheel bearing device C.

  The motor part A includes a stator 3 fixed to the casing 2, a rotor 4 disposed with an axial gap (axial gap) provided inside the stator 3, and a rotor 4 fitted inside the rotor 4 It is comprised by the axial gap motor provided with the motor side rotating member 5 which rotates integrally. Further, an end cap 6 for preventing dust from entering the inside of the motor unit A is attached to the opening on the inner side of the motor unit A.

  The rotor 4 includes a hollow cylindrical portion 4a having a spline (or serration) formed on the inner periphery, and a disk-shaped flange portion 4b extending radially outward from the cylindrical portion 4a. The double row rolling bearings 7 and 7 are rotatably supported with respect to the casing 2. An oil seal 8 is installed between the casing 2 and the rotor 4 to prevent the lubricating oil sealed in the speed reduction part B from entering the motor part A.

  In addition, although what used the axial gap motor for the motor part A was illustrated here, not only this but the motor of arbitrary structures is applicable, for example, although not shown in figure, it fixes to the inner periphery of a casing A radial gap motor may be provided that includes a stator and a rotor opposed to the inner diameter side of the stator via a radial gap.

  The motor-side rotating member 5 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 the eccentric parts 5a and 5b are integrated in the speed reduction part B. Is formed. The motor-side rotating member 5 has an inner end that is spline-fitted to the cylindrical portion 4a of the rotor 4 and a rolling bearing 9 and 10 that includes a pair of angular ball bearings on both sides of the speed reduction portion B. And it is rotatably supported with respect to the connecting member 11. Further, the two eccentric portions 5a and 5b are formed by changing the phase by 180 ° so that the centrifugal forces due to the eccentric motion cancel each other.

  The deceleration part B is held at a fixed position on the casing 2 and curved plates 12a and 12b that are revolving members that are rotatably held by the eccentric parts 5a and 5b, and engages with the outer peripheral parts of the curved plates 12a and 12b. A plurality of outer pins 13, 13 serving as outer peripheral engagement members, a motion conversion mechanism 14 for transmitting the rotational motion of the curved plates 12 a, 12 b to the connecting member 11, and two counterweights 15 attached to the motor side rotating member 5 , 15. These counterweights 15 and 15 are formed in a disc shape, and in order to cancel out the unbalanced inertia couple generated by the rotation of the curved plates 12a and 12b, the eccentric portions 5a and 5b are positioned at positions adjacent to the eccentric portions 5a and 5b. 5b and 180 ° phase are changed.

  The connecting member 11 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and has a flange portion 16 extending radially outward at an end portion on the inner side, and protrudes in an axial direction from the flange portion 16. The provided shaft portion 17 is integrally formed. A plurality of inner pins 18, 18 are fixed to the flange portion 16 at equal intervals on the circumference around the rotation axis of the connecting member 11, and a wheel bearing device to be described later is attached to the shaft portion 17. A fitting profile 28 that is separably connected to the inner member 24 that constitutes C is formed, and a male screw 17 a is formed at an end of the fitting profile 28.

  Next, the motion conversion mechanism 14 will be described with reference to FIG. The curved plate 12a has a plurality of corrugations composed of a trochoidal curve such as epitrochoid on the outer peripheral portion, and a plurality of through holes 19 and 19 and a bearing hole 20 are formed. A plurality of through holes 19 are formed at equal intervals on a circumference centered on the rotation axis of the curved plate 12a, and an inner pin 18 to be described later is fitted therein. The bearing hole 20 is formed at the center of the curved plate 12a and is fitted to the eccentric portion 5a. The curved plate 12a is rotatably supported with respect to the eccentric portion 5a by a rolling bearing 21 formed of a deep groove ball bearing.

  The outer pins 13 are provided at equal intervals on a circumferential track centering on the rotation axis of the motor-side rotating member 5. Since these outer pins 13 coincide with the revolution trajectories of the curved plates 12a and 12b, when the curved plates 12a and 12b revolve, the curved waveform and the outer pin 13 are engaged, and the curved plates 12a and 12b A rotation motion is caused in 12b. Further, in order to reduce the frictional resistance with the curved plates 12a and 12b, needle roller bearings 13a are mounted at positions where they are in rolling contact with the outer peripheral surfaces of the curved plates 12a and 12b (see FIG. 3).

  Here, as shown in FIG. 4, when the center point between the two curved plates 12a and 12b is G, the distance between the central point G and the center of the curved plate 12a is L1 for the inner side of the central point G. The mass of the curved plate 12a is m1, the amount of eccentricity of the center of gravity of the curved plate 12a from the rotational axis is ε1, the distance between the center point G and the counterweight 15 is L2, the mass of the counterweight 15 is m2, and the counterweight 15 Assuming that the amount of eccentricity of the center of gravity from the rotation axis is ε2, L1 × m1 × ε1 = L2 × m2 × ε2 is satisfied. A similar relationship is established between the curved plate 12 b on the outer side of the center point G and the counterweight 15.

  As shown in FIG. 2, the motion conversion mechanism 14 includes a plurality of inner pins 18 and 18 held by the connecting member 11 and through holes 19 provided in the curved plates 12 a and 12 b. In order to reduce the frictional resistance with the through hole 19, the inner pin 18 is mounted with a needle roller bearing 18 a at a position where it comes into rolling contact with the inner peripheral surface of the through hole 19. On the other hand, the through hole 19 is formed at a position corresponding to each of the plurality of inner pins 18, and the inner diameter dimension of the through hole 19 is set to a predetermined amount larger than the outer diameter dimension of the inner pin 18 including the needle roller bearing 18a. (See FIG. 3).

Next, the operation principle of the in-wheel motor drive device 1 according to the present invention will be described with reference to FIG.
The motor part A receives an electromagnetic force generated by supplying an alternating current to the coil 3a of the stator 3, and the rotor 4 having the permanent magnet (or magnetic body) 4c fixed to the flange part 4b rotates. At this time, the rotor 4 rotates at a higher speed as a high frequency voltage is applied to the coil 3a. As a result, the motor-side rotating member 5 connected to the rotor 4 rotates, and the curved plates 12 a and 12 b revolve around the rotation axis of the motor-side rotating member 5. At this time, the outer pin 13 engages with the curved waveform of the curved plates 12 a and 12 b to cause the curved plates 12 a and 12 b to rotate in the direction opposite to the rotation of the motor-side rotating member 5.

  The inner pin 18 inserted through the through hole 19 rolls into contact with the inner peripheral surface of the through hole 19 as the curved plates 12a and 12b rotate, and the revolving motion of the curved plates 12a and 12b is not transmitted to the inner pin 18. In addition, only the rotational movement of the curved plates 12 a and 12 b is transmitted to the hub wheel 25 via the connecting member 11. As described above, since the rotation of the motor-side rotating member 5 is decelerated by the deceleration unit B and transmitted to the connecting member 11, even when the low torque, high rotation type motor unit A is adopted, the torque necessary for the wheels can be obtained. It is possible to communicate.

  The speed reduction ratio of the speed reduction part B is calculated as (Za−Zb) / Zb, where Za is the number of outer pins 13 and Zb is the number of waveforms of the curved plates 12a and 12b. For example, when Za = 12, Zb = 11, the reduction ratio is 1/11, and an extremely large reduction ratio can be obtained even with a compact configuration without using a multistage configuration.

  As shown in an enlarged view in FIG. 5, the wheel bearing device C includes an outer member 22 and an inner member inserted into the outer member 22 via double-row rolling elements (balls) 23 and 23. 24. The outer member 22 integrally has an attachment flange 22b for attaching to the casing 2 on the outer periphery, and double row outer rolling surfaces 22a and 22a are formed on the inner periphery. This outer member 22 is made of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and at least the double row outer raceway surfaces 22a and 22a have a surface hardness in the range of 58 to 64HRC by induction hardening. Is cured.

  The inner member 24 includes a hub ring 25 and an inner ring 27 fixed to the hub ring 25. The hub wheel 25 integrally has a wheel mounting flange 26 for mounting a wheel (not shown) at an end portion on the outer side, and is on one side (outer side) of the double row outer rolling surfaces 22a and 22a on the outer periphery. An opposed inner rolling surface 25a and a cylindrical small diameter step portion 25b extending in the axial direction from the inner rolling surface 25a are formed. Hub bolts 26a for fixing the wheels to the circumference of the wheel mounting flange 26 are equally planted.

  On the other hand, the inner race 27 is formed with an inner raceway surface 27a facing the other (inner side) of the double row outer raceway surfaces 22a and 22a on the outer periphery, and a small diameter step portion 25b of the hub wheel 25 via a predetermined squeezing It is press-fitted. And it fixes to the axial direction with the crimping part 25c formed by carrying out the plastic deformation of the edge part of the small diameter step part 25b to radial direction outward.

  The hub wheel 25 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and includes an inner rolling surface 25a and a wheel mounting flange 26 that serves as a seal land portion of an outer seal 30 described later. The surface 26 is hardened in a range of 58 to 64 HRC by induction hardening from the base portion 26b to the small diameter step portion 25b. The inner ring 27 and the rolling element 23 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC up to the core part by quenching.

  Here, the shaft portion 17 of the connecting member 11 is constituted by a short shaft, the male screw 17a is formed at the end portion, and a fitting profile 28 as shown in FIG. 6 is formed on the outer periphery. As for this fitting profile 28, the convex tooth 28a is formed in the outer periphery by multiple (3-10) equal distribution. As shown in FIG. 7, the convex tooth 28a is formed into a substantially trapezoidal cross section by traversing an end mill 29 whose tip is formed at a predetermined inclination angle (pressure angle α) in the direction of the axis (arrow). The tooth surface has a predetermined inclination angle β in the axial direction with respect to the axial center. Here, as shown in FIG. 6 (c), the pressure angle α is negative (α <0) when the convex teeth 28a face outward in the circumferential direction and the tooth width increases, and conversely the tooth width decreases. This state is defined as positive (α> 0).

  On the other hand, on the inner periphery of the hub wheel 25, a fitting profile 30 is formed in which a plurality of concave grooves 30a corresponding to the fitting profile 28 are equally arranged. The concave groove 30a is formed in a dovetail shape by forging and has a predetermined pressure angle α corresponding to the convex tooth 28a, and the tooth surface has a predetermined inclination angle in the axial direction with respect to the axial center. β is formed.

  The graph shown in FIG. 8 shows the expansion amount of the hub wheel 25 with respect to the pressure angle α at the time of torque transmission and the separation force generated in the engaging portion with constant axial force and torque. The pressure angle α of the concave groove 30a is set in a range of ± 30 ° in which both the expansion amount and the separation force do not increase. Preferably, if the pressure angle α is set in a negative region, that is, in a range of 0 to −30 °, the cross-sectional shape of the recessed groove 30a in the hub wheel 25 becomes a dovetail shape, and the expansion of the hub wheel 25 is caused. It can be effectively suppressed.

  The graph shown in FIG. 9 shows the expansion amount of the hub wheel 25 with respect to the inclination angle β during torque transmission and the separation force generated in the engaging portion with constant axial force and torque. The inclination angle β of the recessed groove 30a is set in the range of 2 to 7 °, preferably 3 to 6 °, in which both the expansion amount and the separation force do not increase. As the inclination angle β decreases, the combined tolerance width of the convex teeth 28a and the recessed grooves 30a increases. However, by setting β = 2 to 7 °, the combined tolerance width can be suppressed to ± 1 mm or less. An axial clearance δ between a shoulder portion 16a of the connecting member 11, which will be described later, and an end surface of the caulking portion 25c can be ensured. Here, the module m is set to 3 to 10 in consideration of the strength and economic aspects of the convex teeth 28a and the concave grooves 30a (approximately 3 to 10 teeth). Here, m = d / z (d: average diameter in the axial direction of the fitting profile, z: number of teeth or number of grooves). Further, at least the convex teeth 28a out of the convex teeth 28a and the concave grooves 30a are subjected to a hardening process in a range of 58 to 64 HRC by induction hardening.

  Then, as shown in FIG. 5, the shaft portion 17 of the connecting member 11 has these fitting profiles such that a predetermined axial clearance δ is interposed between the shoulder portion 16a of the connecting member 11 and the end surface of the crimped portion 25c. The hub wheel 25 is fitted to the hub wheel 25 via 28 and 30, and the fixing nut 31 is fastened to the male screw 17 a of the shaft portion 17, so that the hub wheel 25 and the connecting member 11 are coupled in a separable manner in the axial direction. Here, the axial clearance δ is set to 1 mm or more from the combined tolerance width of the convex teeth 28a and the concave grooves 30a.

  Thus, since the hub wheel 25 and the connecting member 11 are connected via the fitting profiles 28 and 30 so as to be able to transmit torque, the speed reduction part B and the wheel bearing device C can be separated, and can be assembled and disassembled. Thus, an in-wheel motor drive device with improved maintainability can be provided.

  Furthermore, since the fitting profiles 28 and 30 have a predetermined pressure angle α and are respectively configured by convex teeth 28a and concave grooves 30a formed with a predetermined inclination angle β in the axial direction with respect to the axial center, Therefore, it is possible to easily obtain a strong fitting state without a backlash in the circumferential direction at the final stage of insertion, and to be generated in the engaging portion of the convex tooth 28a and the concave groove 30a at the time of torque transmission. The component force in the radially outward direction can be suppressed, and the bearing clearance is not adversely affected by the expansion of the hub wheel 25. Therefore, it is possible to realize a strong connection without backlash and to prevent the generation of an unpleasant rattling sound over a long period of time.

  Further, since the axial clearance δ is formed between the shoulder portion 16a and the caulking portion 25c, a self-retaining structure capable of maintaining the bearing preload for a long period without firmly tightening the fixing nut 31 is provided. In addition, even when a large torque is applied to the connecting member 11 and torsion occurs, it is possible to prevent the generation of abnormal noise caused by metal contact with the caulking portion 25c, so-called stick-slip noise.

  An end cap 32 is attached to the outer end of the hub wheel 25, and the open end of the outer side of the hub wheel 25 is closed. Thereby, it can prevent that foreign materials, such as rain water and dust, penetrate | invade into the engaging part of the convex tooth 28a and the concave groove 30a, and can prevent rusting of an engaging part over a long period of time.

  Further, between the rolling surfaces of the outer member 22 and the inner member 24, double-row rolling elements 23, 23 are accommodated so as to be freely rollable via the retainers 33, 33, and the outer member 22, Seals 34 and 35 for sealing the opening of the annular space formed between the inner member 24 and the inner member 24 are mounted. Out of these seals 34 and 35, the outer seal 34 has a pair of side lips that are in sliding contact with the base portion 26b and a grease lip that is inclined toward the bearing inward side. Thereby, a compact seal with high sealing performance can be obtained, and the bearing span can be maximized, so that the durability of the wheel bearing device C can be improved.

  An oil seal 36 is attached to the outer end of the casing 2, and the opening of the annular space formed between the casing 2 and the connecting member 11 is sealed. This oil seal 36 has a garter spring 36a, shuts off the bearing portion and the speed reduction portion B, and prevents the lubricating oil that lubricates the speed reduction portion B from entering the inside of the bearing. That is, foreign matter such as metal wear powder mixed in the lubricating oil of the deceleration portion B is prevented from entering the bearing and deteriorating the peeling life. And the bearing part is lubricated with the grease enclosed inside. Thereby, the bearing part can ensure a desired peeling life without being affected by the cleanliness of the lubricating oil that lubricates the inside of the speed reduction part B.

  Here, the third generation structure in which the inner rolling surface 25a is directly formed on the outer periphery of the hub wheel 25 is illustrated. However, the present invention is not limited to this, but a pair of inner rings are press-fitted into the hub wheel. It may be a first or second generation structure. Moreover, although the structure which consists of a double row angular contact ball bearing which used the ball for the rolling element 23 was illustrated, the double row tapered roller bearing which used the tapered roller for the rolling element may be sufficient.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  An in-wheel motor drive device according to the present invention includes a motor unit, a wheel bearing device to which a wheel is attached, and a speed reducing unit that decelerates the rotation of the motor unit and transmits the rotation to the wheel bearing device. The present invention can be applied to an in-wheel motor drive device arranged in a shape.

It is a longitudinal section showing one embodiment of the in-wheel motor drive concerning the present invention. It is a cross-sectional view along the II-II line of FIG. FIG. 3 is an enlarged view of a main part of FIG. 2. It is a principal part enlarged view which shows the eccentric part of FIG. It is an enlarged view which shows the wheel bearing apparatus of FIG. (A) is a front view which shows the fitting profile of the axial part in the connection member of FIG. (B) is a cross-sectional view along the VI-VI line of (a). (C) is explanatory drawing which shows the difference in the shape when the pressure angle of a fitting profile is negative, and when it is positive. (A) is a front view which shows the manufacturing method of a fitting profile. (B) is a cross-sectional view along the line VII-VII. It is a graph which shows the amount of expansion | swelling of the hub ring with respect to the pressure angle of a fitting profile, and the separation force generate | occur | produced in an engaging part. It is a graph which shows the expansion amount of the hub ring with respect to the inclination angle of a fitting profile, and the separation force which generate | occur | produces in an engaging part. It is a longitudinal cross-sectional view which shows the conventional in-wheel motor drive device.

Explanation of symbols

1. In-wheel motor drive device 2 ... Casing 3 ... Stator 3a ... ... Coil 4 ... Rotor 4a ... Cylindrical part 4b, 16 ... Flange part 4c ... .... Permanent magnet 5 ......... Motor-side rotating members 5a, 5b ......... Eccentric parts 6, 32 ......... End caps 7, 9 10, 21 ... Rolling bearings 8, 36 ... Oil seal 11 ... Connecting members 12a, 12b ... Curved plate 13 ... ···················································································· Needle roller bearings 14 ······· Motion conversion mechanism 15 ················· Counterweight 16a・...... Shoulder 17 ... Shaft 17a ... Male thread 18 ... Inner pin 19 ... ... through hole 20 ... bearing hole 22 ... outer member 22a ... outer rolling surface 22b ..... Mounting flange 23 .... Rolling element 24 .... Inner member 25 ..... Hub wheel 25a, 27a ... Inner rolling surface 25b ... Small diameter step 25c ... Caulking part 26 ... Wheel Mounting flange 26a ... hub bolt 26b ... base 27 ... inner ring 28, 30 ... fitting profile 29 ............ End mill 31 ... ······························································· Outer seal 35 Seal 32a ... garter spring 50 ... in-wheel motor drive 51 ... body 52 ... ... Casing 53 ... Motor part 54 ... Wheel 55 ... Wheel bearing device 56 ...・ ・ ・ ・ ・ Hub wheels 56a, 65a ... Inner rolling surface 56b ... Small diameter step 57 ... Reduction gear 58 ...・ ・ ・ ・ ・ ・ Motor side rotating members 58a, 58b ...... Eccentric parts 59a, 59b ... Curve plates 60a, 60b ... Rolling bearings 61 ... ... Outer pin 62 ... Inner member 63 ... Inner pin 64 ... Outer member 64a ... ··· Outer rolling surface 64b ... Mounting flange 65 ... Inner ring 66 ... Ball 67 ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange A ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Motor B ・ ・ ・ ・ ・ ・ ・ ・ Speed reduction C ・ ・ ・ ・ ・ ・ ・ ・Wheel bearing device d ... Mean diameter G of fitting profile ... Center point L1 between curved plates ...・ Distance L2 between the center point and the center of the curved plate .... Distance m between the center point and the center of the counterweight .... Module m1 ..・ ・ ・ ・ Mass of curved plate m2 ・ ・ ・ ・ ・ ・ ・ ・・ Weight of counterweight z ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Number of teeth or grooves Za ・ ・ ・ ・ ・ ・ ・ ・ Number of outer pins Zb ・ ・ ・ ・ ・ ・ Curve plate Number of waveforms α ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pressure angle β ・ ・ ・ ・ ・ ・ Inclination angle δ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Axial clearance ε1 ・ ・・ ・ ・ ・ ・ ・ ・ ・ Eccentricity of the center of gravity of the curved plate from the rotational axis ε2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Eccentricity of the center of gravity of the counterweight from the rotational axis

Claims (5)

A casing,
A motor unit that is disposed in the casing and rotationally drives a motor-side rotating member in which an eccentric portion is integrally formed; and
A speed reducer that decelerates the rotation of the motor side rotating member;
In an in-wheel motor drive device including a wheel bearing device that is coupled to the speed reduction portion so as to be able to transmit torque and rotatably supports a wheel.
The wheel bearing device is coupled to the speed reduction portion via a connecting member, and the wheel bearing device has an attachment flange for being attached to the casing on the outer periphery, and a double row outer roll on the inner periphery. An outer member integrally formed with a running surface;
A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end and having a cylindrical small-diameter step portion extending in the axial direction on the outer periphery, and at least one press-fitted into the small-diameter step portion of the hub ring An inner member formed of two inner rings and formed with a double-row inner rolling surface facing the double-row outer rolling surface;
A double row rolling element housed so as to be freely rollable between both rolling surfaces of the inner member and the outer member;
A flange portion that includes a seal mounted on at least an outer opening portion of an annular space formed between the outer member and the inner member, and the connecting member extends radially outward. And a shaft portion protruding in the axial direction from the flange portion, and the connecting member and the hub wheel are detachably coupled in the axial direction via screw means,
The coupling portion corresponds to the fitting profile formed by arranging a plurality of convex teeth on the outer periphery of the shaft portion of the connecting member, and corresponds to the fitting profile, on the inner periphery of the hub wheel, to the convex teeth. It is configured with a fitting profile formed by arranging a plurality of concave grooves having a cross-sectional dovetail shape to be engaged,
The in-wheel motor drive device characterized in that the convex teeth are formed in a substantially trapezoidal cross section having a predetermined negative pressure angle, and a predetermined inclination angle is formed in the axial direction with respect to the axial center on the tooth surface.   The inner ring is fixed to the hub ring in the axial direction with a predetermined bearing preload applied by a caulking portion formed by plastically deforming an end of the small diameter step portion radially outward. 2. The in-wheel motor drive device according to claim 1, wherein the connection member and the hub wheel are coupled so that a predetermined axial clearance is interposed between a shoulder portion of the connection member and an end surface of the crimping portion. .   A seal is attached to the opening of the annular space formed between the outer member and the inner member, the bearing portion is grease lubricated, and an oil seal is attached to the outer end of the casing, The in-wheel motor drive device of Claim 1 or 2 with which the opening part of the annular space formed between the said casing and a connection member is sealed.   An inner rolling surface facing one of the double-row outer rolling surfaces is directly formed on the outer periphery of the hub wheel, and an inner side base portion of the wheel mounting flange is formed in an arc shape, and the outer side seal is formed. 4. The in-wheel motor drive device according to claim 1, further comprising: a side lip that is in sliding contact with the base portion; and a grease lip that is inclined inward of the bearing.   The speed reduction part has a plurality of waveforms composed of trochoidal curves on the outer periphery, a plurality of through holes are formed through the eccentric part, and the rotation axis of the motor side rotation member is rotated. A curved plate that performs a revolving motion as a center, a plurality of outer pins that are brought into rolling contact with an outer peripheral portion of the curved plate via a needle roller bearing, and are fixed to the flange portion of the connecting member, An inner pin that is in rolling contact with the inner periphery of the through hole via a needle roller bearing, and the rotational movement of the curved plate is converted into a rotational movement centered on the rotational axis of the motor-side rotating member, The in-wheel motor drive device in any one of Claims 1 thru | or 4 comprised by the cycloid reduction mechanism transmitted to a connection member.

Images