JP2015020707A - Wheel bearing device with built-in type in-wheel motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel bearing device with a built-in type in-wheel motor which is capable of replacing a hub bearing without draining lubrication oil.SOLUTION: An electric motor 16 is assembled into a housing, and a driving axle 26 is provided for an outboard side of an input shaft 24 that integrally rotates with a rotor of the electric motor. A planetary gear-type speed reducer 50 that reduces the rotation speed of the input shaft 24 and transmits it to the driving axle 26 is assembled into the housing. An area between an outer diameter surface of a large diameter shaft part 26a of the driving axle 26 and an inner diameter surface of an opening part 27 is sealed by assembling an oil seal 28, which eliminates the need of draining lubrication oil housed in the housing when replacing a hub bearing 30 that supports the driving axle 26 freely rotatably.

Description

  The present invention relates to an in-wheel type motor-integrated wheel bearing device for driving a wheel wheel of an automobile.

  An in-wheel motor type is known as an electric vehicle drive type. In this in-wheel motor type electric vehicle drive device, for example, as described in Patent Document 1, the rotation of the input shaft that is rotationally driven by the electric motor is decelerated by a planetary gear type reduction gear, The rotation of the output shaft of the reduction gear is transmitted to a hub that is spline-fitted to the output shaft to rotate the wheel.

  By the way, in the electric vehicle driving apparatus described in Patent Document 1, the rotor is rotatably supported via a bearing on a sleeve bolted to the case, and an input shaft that rotates integrally with the rotor is also attached to the case. It is a complicated structure that is supported by a bearing, and manufacturing errors and assembly errors are accumulated for each part, so it is difficult to ensure accuracy, and it takes time and effort to assemble, and the cost is high. .

  Patent Documents 2 and 3 also propose an in-wheel motor drive device for an electric vehicle. However, as in Patent Document 1, the structure is complicated and it is difficult to ensure accuracy, and it is troublesome to assemble. There is an inconvenience that it takes. Further, since the motor and the speed reducer are accommodated in the unit case, it is considered that the cooling of the motor is a lubricating oil that lubricates the speed reducer. In this case, since the lubricating oil for gear-lubricating the reduction gear has a high viscosity, when used for cooling the electric motor, the motor efficiency is adversely affected and the amount of electricity consumed increases.

  In order to eliminate such inconvenience, the applicant of the present invention in Patent Document 4 partitions the interior of the housing into a motor accommodating space and a reducer accommodating space by a partition wall, and incorporates an electric motor in the motor accommodating space. A pair of bearings in which a reduction gear is incorporated in the housing space, only the reduction gear is lubricated by the lubricating oil stored in the reduction gear housing space, and the input shaft driven by the electric motor is supported by the output member. A drive device for an electric vehicle that is supported is proposed.

  In the electric vehicle driving apparatus, since only the speed reducer can be lubricated by the lubricating oil stored in the speed reducer housing space, the lubricating oil does not adversely affect the rotation of the electric motor.

  Further, since the input shaft is cantilevered by supporting a pair of bearings that rotatably support the input shaft with the output member, the support structure can be simplified, and the wheel can be changed to the output member. Since the transmitted vibrations and shocks are simultaneously applied to the pair of bearings in the same manner, an offset load does not act on the pair of bearings, and the rotation accuracy of the input shaft and the durability of the bearing are improved. It has the feature of being able to.

US Pat. No. 5,382,854 JP 2011-31792 A JP 2012-51065 A JP2012-184817A

  By the way, in the electric vehicle drive device described in Patent Document 4, the outer member is bolted to the outer surface of the front end portion of the housing, and the end portion on the inboard side of the outer member and the facing portion of the output member An oil seal is installed in between to prevent leakage of lubricating oil stored in the reducer housing space, and on the outside of the oil seal, a rolling bearing is incorporated inside the outer member and a hub fitted to the output member is installed. Since it is rotatably supported, the oil seal is also removed at the same time when the outer member is removed during maintenance or replacement of the rolling bearing due to damage. For this reason, it is necessary to remove the outer member after extracting the lubricating oil, and there is a problem that work is very troublesome.

  In addition, as the rolling bearing, a double-row inner ring is incorporated in the outer ring, and a sealed angular contact unit bearing with a double-row ball incorporated between each inner ring and the outer ring is used. Since a preload is applied to the rolling bearing by tightening a nut that prevents the hub from being removed, variations in preload are large and variations in torque are large.

  Furthermore, in a rolling bearing with a seal, since the seal becomes a rotational resistance, there is also a problem that the torque loss is large and the motor efficiency is lowered.

  An object of the present invention is to provide a bearing device for an in-wheel type motor built-in motor that can replace a hub bearing without extracting lubricating oil.

  In order to solve the above problems, in the present invention, a housing, an electric motor accommodated in the housing, an input shaft provided on the axis of the rotor of the electric motor and rotating integrally with the rotor, A drive axle provided coaxially with the input shaft and having an end on the outboard side inserted into an opening provided in an end wall of the housing and facing the outside, and incorporated in the housing, the input shaft is rotated. And a hub bearing having a hub that rotatably supports the drive axle and transmits the rotation of the drive axle to a wheel wheel, and is stored in the housing. In the in-wheel motor-equipped wheel bearing device that lubricates the speed reducer with the lubricating oil, the drive axle has a large-diameter shaft portion disposed in the opening, An outer diameter surface of the shaft portion between the inner diameter surface of the opening portion of the housing is of employing the configuration sealed by the incorporation of the oil seal.

  Here, a planetary gear type reduction gear or a cycloid reduction gear can be employed as the reduction gear.

  As described above, even if the hub bearing is removed by providing a large-diameter shaft portion on the drive axle and sealing between the outer diameter surface of the large-diameter shaft portion and the inner diameter surface of the opening by incorporating an oil seal. The inside of the housing can be kept sealed. For this reason, the hub bearing can be replaced without extracting the lubricating oil stored in the housing.

  Here, as a hub bearing, a hub fitted to the drive axle so as not to rotate relatively, a bearing inner ring fitted to a small-diameter cylindrical portion at an end of the inboard side of the hub, and an outer wall of the end wall of the housing. Adopting a bearing outer ring mounted freely, and a double row rolling element incorporated in the bearing outer ring and rotatably supporting each of the hub and the bearing inner ring, the shaft end of the drive axle is adopted. By preloading the hub bearing by pressing the inner ring of the bearing against the shaft end surface of the large-diameter shaft portion by tightening a nut that is screw-engaged to prevent the hub from being pulled out, the preload variation factor of the hub bearing can be reduced. For this reason, variations in preload can be reduced.

  Also, by opening the gap between the bearing outer ring and the bearing inner ring on the inboard side in the hub bearing, the rotational resistance is less than that of a sealed hub bearing with a seal on the inboard side, and the torque of the electric motor Loss can be reduced.

  In the use of an inboard open type hub bearing as described above, a seal ring is incorporated between the facing portion of the bearing outer ring with respect to the housing opening and between the facing portion of the small diameter cylindrical portion of the hub and the large diameter shaft portion of the drive axle. In addition, it is possible to seal between the bearing outer ring and the facing portion of the opening and between the driving axle and the facing portion of the hub, and reliably prevent muddy water from entering the inside from the open portion of the hub bearing.

  Also, if a seal ring is incorporated between the bearing outer ring and the facing part of the opening, and a cap is incorporated in the opening of the cylindrical pilot part provided at the end of the hub on the outboard side, the bearing outer ring and the opening are opened. It is possible to prevent muddy water from entering between the facing parts of the parts. Further, it is possible to prevent muddy water from entering from the pilot section. For this reason, similarly to the above, the intrusion of muddy water from the open part of the hub bearing to the inside can be reliably prevented.

  In the in-wheel type motor-equipped wheel bearing device according to the present invention, when a planetary gear type reduction gear is adopted as the reduction gear, the planetary gear of the planetary gear type reduction gear has a pin hole formed in the carrier portion of the drive axle. With respect to the pin whose both ends are supported, the needle roller bearing disposed at the pin outer diameter portion is rotatably supported. On the other hand, the inner ring of the hub bearing is pressed against the shaft end surface of the large-diameter shaft portion of the drive axle to apply preload to the hub bearing. Therefore, the shaft end surface of the large-diameter shaft portion is heat treated to prevent buckling. Need to increase. At this time, if heat treatment is applied to the entire outer surface of the drive axle, the hardness of the pin hole forming portion is increased and it is difficult to process the pin hole.

  Therefore, if the range from the outer diameter surface of the drive axle to the shaft end surface of the large diameter shaft portion is heat-treated to provide a hardened layer on the surface layer portion, the processing of the pin hole can be facilitated.

  Here, the oil seal has a pair of radial lips that are elastically contacted with the cylindrical portion of the slinger having an L-shaped cross-section press-fitted into the outer diameter surface of the large-diameter shaft portion, and an axial lip that is elastically contacted with the flange of the slinger. By adopting the pack type, it is not necessary to heat treat the fitting portion of the slinger, so that the heat treatment range can be further reduced and the processing cost can be reduced. Further, the influence of heat on the pin hole forming portion can be further reduced, and the pin hole can be more easily processed.

  In the inboard open type hub bearing as described above, although the rotational resistance is small and the torque loss of the electric motor can be reduced, the grease that lubricates the bearing is likely to leak. Therefore, if a labyrinth is provided between the bearing outer ring and the bearing inner ring of the hub bearing, the effect of preventing grease leakage can be obtained.

  Here, when the wheel wheel is attached to the hub, if the wheel bolt type is to tighten the bolt by screwing the bolt into the screw hole of the flange provided on the outer periphery of the hub from the bolt insertion hole formed in the wheel wheel, the hub bolt type In comparison, it is not necessary to secure a space for pulling out the bolts, so that the in-wheel type motor-equipped wheel bearing device can be thinned.

  Also, in the double row rolling element row in the hub bearing, the pitch circle diameter of the inboard side rolling element row that rotatably supports the bearing inner ring is larger than the pitch circle diameter of the outboard side rolling element row that rotatably supports the hub. If it is increased, the span can be increased and the number of rolling elements in the inboard side rolling element row can be made larger than the number of outboard side rolling elements, so that the bearing rigidity can be increased.

  In the present invention, as described above, the drive axle is provided with a large diameter shaft portion, and an oil seal is incorporated between the outer diameter surface of the large diameter shaft portion and the inner diameter surface of the opening formed in the end wall of the housing. By sealing, the hub bearing space can be kept sealed even if the hub bearing is removed, so the hub bearing can be replaced without draining the lubricating oil stored in the reducer housing space. Can do.

Sectional drawing which shows embodiment of the bearing apparatus for in-wheel type motor built-in wheels which concerns on this invention 1 is a longitudinal cross-sectional view of the in-wheel motor-equipped wheel bearing device shown in FIG. FIG. 2 is an enlarged cross-sectional view of the oil seal built-in portion of FIG. Sectional view showing another example of hub bearing Sectional view showing the sealing device of the hub bearing built-in part Sectional drawing which shows the other example of the sealing device in a hub incorporating part Sectional drawing which shows other embodiment of the in-wheel type motor built-in wheel bearing device based on this invention Sectional view showing another example of oil seal Sectional view showing another example of hub bearing Sectional view showing still another example of hub bearing Sectional drawing which shows other embodiment of the bearing apparatus for in-wheel type motor built-in wheels concerning this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 show an embodiment of a bearing device for an in-wheel type motor built-in wheel according to the present invention, which has a housing 10. The housing 10 has a cylindrical shape, one end in the axial direction is opened, and the other end is closed by an end plate 11. The opening at one end is closed by attaching the cover 12.

  A cylindrical portion 13 is provided on the inner surface of the end plate 11, and the outer peripheral portion of the partition wall 14 is bolted to the end surface of the cylindrical portion 13. The partition wall 14 has a cap shape, and the interior of the housing 10 is partitioned into a motor storage space 15a and a reduction gear storage space 15b by attaching the partition wall 14.

  An electric motor 16 is incorporated in the motor housing space 15a. The electric motor 16 has a stator 17 fixed to the inner diameter surface of the motor housing space 15 a and a rotor 18 incorporated inside the stator 17, and the rotor 18 rotates by energization of the coil 17 a of the stator 17.

  The rotor 18 is supported on the outer peripheral portion of the rotor support member 19. A plurality of punch holes 20 are formed in the rotor support member 19 at equal intervals in the circumferential direction, and a boss portion 21 is provided at the center.

  The boss portion 21 is inserted into a shaft insertion hole 22 formed in the central portion of the partition wall 14, and an end thereof faces the speed reducer housing space 15 b, and the outer diameter surface of the boss portion 21 and the inner diameter surface of the shaft insertion hole 22. The space is sealed by incorporating an oil seal 23.

  An input shaft 24 is inserted inside the boss portion 21. The input shaft 24 is prevented from rotating around the rotor 18 by a key 25 and rotates together with the rotor 18.

  The input shaft 24 is inserted into the shaft insertion hole 22 formed in the partition wall 14 through the boss portion 21, and the end portion on the inboard side faces the motor housing space 15 a, while the outboard The end on the side is located in the reduction gear housing space 15b.

  A drive axle 26 is provided on the outboard side of the input shaft 24. The drive axle 26 is arranged coaxially with the input shaft 24, and an end portion on the outboard side is inserted into an opening portion 27 formed in the center portion of the end plate 11 of the housing 10 and faces the outside.

  A large-diameter shaft portion 26 a is provided at the end of the drive axle 26 on the input shaft 24 side on the inboard side, and an oil seal 28 is provided between the outer diameter surface of the large-diameter shaft portion 26 a and the inner diameter surface of the opening 27. It is sealed by incorporating.

  An end portion on the outboard side of the drive axle 26 is rotatably supported by the hub bearing 30.

  The hub bearing 30 includes a hub 31 that is spline-fitted to the drive axle 26, a bearing inner ring 32 provided at an inboard side end portion of the hub 31, and an inboard side end portion of the bearing inner ring 32 and the hub 31. A bearing outer ring 33 to be covered, and a double row for rotatably supporting the hub 31 and the bearing inner ring 32 are incorporated between the bearing outer ring 33 and the opposed surfaces of the hub 31 and between the bearing outer ring 33 and the opposed surfaces of the bearing inner ring 32. The bearing inner ring 32 includes rolling elements 34 a and 34 b, and is fitted into a small-diameter cylindrical portion 31 a formed at an inboard side end portion of the hub 31.

  An end portion of the bearing outer ring 33 on the inboard side is guided by the opening 27 and a vehicle body mounting flange 33 a provided on the outer diameter surface is abutted against the outer surface of the end plate 11, and the vehicle body mounting flange 33 a is the end plate 11. It is attached to the end plate 11 by tightening a bolt 35 screwed into the end plate 11.

  The hub 31 is fitted to the shaft end portion of the drive axle 26, is prevented from rotating around the drive axle 26 by the serration 36, and rotates integrally with the drive axle 26. A wheel mounting flange 31b is provided on the outer periphery of the end portion on the outboard side facing the outside from the bearing outer ring 33 of the hub 31, and a nut 38 is screw-engaged with a hub bolt 37 supported by the wheel mounting flange 31b. The wheel wheel 39 and the brake rotor 40 are attached to the wheel attachment flange 31b by tightening.

  A small-diameter screw shaft portion 26b is provided at the shaft end portion of the drive axle 26, and the hub 31 is prevented from being pulled out by tightening a nut 41 screw-engaged with the screw shaft portion 26b. Further, by tightening the nut 41, the bearing inner ring 32 of the hub bearing 30 is pressed against the shaft end surface of the large-diameter shaft portion 26a, and a preload is applied to the hub bearing 30.

  At this time, since the preload can be managed only by tightening the nut 41, variations in the preload can be suppressed.

  Openings at both ends in the axial direction of the bearing outer ring 33 are sealed by incorporating seals 42 and 43.

  As shown in FIG. 2, a shaft insertion hole 44 is formed at the end of the drive axle 26 facing the input shaft 24. A pair of bearings 45 are incorporated in the shaft insertion hole 44 at intervals in the axial direction, and the ends of the input shaft 24 are rotatably supported by the pair of bearings 45.

  A reduction gear 50 that reduces the rotation of the input shaft 24 and transmits it to the drive axle 26 is provided in the reduction gear housing space 15b.

  The speed reducer 50 includes a sun gear 51 provided at the shaft end of the input shaft 24, an internal gear 52 fitted and fixed to the inner diameter surface of the speed reducer housing space 15b, and an inner periphery of the internal gear 52. It consists of a planetary gear type consisting of an inner tooth and a planetary gear 53 meshing with each of the outer teeth on the outer periphery of the sun gear 51.

  The planetary gear 53 is rotatably supported by a carrier portion 54 provided on the outer periphery of the inboard side end portion of the large-diameter shaft portion 26a of the drive axle 26. The carrier portion 54 has a pair of opposed disk portions 55, and a plurality of pairs of pin holes 56 that are axially opposed to the pair of disk portions 55 are provided at intervals in the circumferential direction, and the pair of pin holes 56. The planetary gear 53 is rotatably supported around the pin 57 whose both ends are supported by each of these.

  In the in-wheel motor-equipped wheel bearing device having the above-described configuration, when the rotor 18 is rotationally driven by energization of the coil 17 a of the stator 17, the input shaft 24 rotates together with the rotor 18.

  The rotation of the input shaft 24 is decelerated by the planetary gear type speed reducer 50 and transmitted to the drive axle 26, and the wheel wheel 39 is rotationally driven by the drive axle 26.

  Since the reduction gear 50 that decelerates the rotation of the input shaft 24 and transmits it to the drive axle 26 when driving the wheel wheel 39 as described above is of a planetary gear type, the gear meshing causes wear and durability. descend. In order to suppress the occurrence of such inconvenience, oil is stored in the reducer housing space 15b, and the reducer 50 is lubricated with the stored oil.

  Here, when the amount of oil accommodated in the reducer accommodation space 15b is less than necessary, the reducer 50 cannot be effectively lubricated. Therefore, the amount of lubricating oil is approximately the same level as the central axis of the input shaft 24.

  A reduction gear storage space 15 b for storing lubricating oil of the reduction gear 50 is partitioned by a partition wall 14 from a motor storage space 15 a for storing the electric motor 16, and a shaft insertion hole 22 formed in the partition wall 14 has an oil seal 23. Since it is hermetically sealed by incorporation, the lubricating oil does not enter the motor housing space 15a and affect the rotation of the electric motor 16. Further, even if the metal powder worn by the meshing of the gear is mixed in the oil, the metal powder does not enter the electric motor 16 and affect the rotation.

  The electric motor 16 may be air-cooled, or may be oil-cooled by storing oil in the motor housing space 15a.

  In FIG. 2, the opening 27 formed in the end plate 11 is sealed by incorporating an oil seal 28, so that the lubricating oil does not leak to the outside. At this time, since the oil seal 28 is incorporated between the outer diameter surface of the large-diameter shaft portion 26a and the inner diameter surface of the opening 27 in the drive axle 26, the reduction gear housing is accommodated even if the hub bearing 30 is removed. The space 15b is kept sealed. For this reason, maintenance or replacement of the hub bearing 30 can be performed without extracting the lubricating oil stored in the reduction gear housing space 15b.

  FIG. 4 shows another example of the hub bearing 30. In the hub bearing 30 in this example, the seal 42 on the inboard side of the hub bearing 30 shown in FIG. 2 is omitted, and the gap between the bearing outer ring 33 and the bearing inner ring 32 on the inboard side is open. This is different from the hub bearing 30 shown in FIG.

  As shown in FIG. 4, compared with the sealed hub bearing 30 of FIG. 2 in which a seal is provided on the inboard side by opening the space between the opposing portions on the inboard side of the bearing outer ring 33 and the bearing inner ring 32. There is little rotation resistance and the torque loss of the electric motor 16 can be reduced.

  When the inboard open type hub bearing 30 is used as described above, when muddy water enters from between the facing portion of the opening 27 and the bearing outer ring 33 or between the facing portion of the drive axle 26 and the hub 31, the muddy water is transferred to the hub. There is a possibility that the inside of the bearing 30 may enter the inside from the open portion on the inboard side.

  As countermeasures, in the in-wheel type motor-equipped wheel bearing device in FIG. 5, the opposed outer ring 33 and the opening 27 are opposed to each other and the small-diameter cylindrical portion 31 a of the hub 31 is opposed to the large-diameter shaft portion 26 a of the drive axle 26. A seal ring 60 is incorporated in each of the parts to seal between the opposed surfaces of the bearing outer ring 33 and the opening 27 and between the opposed surfaces of the drive axle 26 and the hub 31, and muddy water from the open part of the hub bearing 30 to the inside. Prevents intrusion.

  In FIG. 6, a seal ring 60 is incorporated between the opposed portions of the bearing outer ring 33 and the opening 27 to prevent intrusion of muddy water from between the opposed portions, and the end portion of the hub 31 on the outboard side. A cap 61 is incorporated in the opening of the cylindrical pilot portion 31c provided in the muffler to prevent muddy water from entering the pilot portion 31c.

  In the hub bearing 30 shown in FIG. 2, the bearing inner ring 32 is pressed against the shaft end surface of the large-diameter shaft portion 26a of the drive axle 26 to apply preload to the hub bearing 30, so that the shaft end surface of the large-diameter shaft portion 26a is a seat. In order to prevent bending, it is necessary to harden it by heat treatment. At this time, if heat treatment is performed on the entire outer surface of the drive axle 26, the hardness of the pin hole forming portion of the carrier portion 54 becomes high, and the processing of the pin hole 56 becomes difficult.

  Therefore, in FIG. 7, only the range from the outer diameter surface of the drive axle 26 to the shaft end surface of the large diameter shaft portion 26a is heat-treated to provide the hardened layer 62 on the surface layer portion. The diagonal lattice-like pattern portion in FIG.

  As described above, only the range from the outer diameter surface of the drive axle 26 to the shaft end surface of the large-diameter shaft portion 26a is subjected to a heat treatment so that the pin hole forming portion does not harden. 56 can be easily processed.

As shown in FIG. 8, as the oil seal 28, a pair of radial lips R ₁ , R ₂ and a slinger that elastically contact a cylindrical portion 63a of a slinger 63 having an L-shaped section press-fitted into the outer diameter surface of the large-diameter shaft portion 26a. by adopting those pack type comprising a axial lip R ₃ elastically contacts the flange 63b of 63, that it does not require heat treating the fitting portion of the slinger 63, it is possible to reduce the heat treatment range, The processing cost can be reduced. Further, the influence of heat on the pin hole forming portion can be further reduced, and the pin hole 56 can be more easily processed.

  9 and 10 show another example of the hub bearing. In the hub bearing 30 shown in FIG. 9, a labyrinth 64 is provided between opposing portions of the bearing outer ring 33 and the bearing inner ring 32.

  In the hub bearing 30 shown in FIG. 10, a slinger 65 having an L-shaped cross section is press-fitted into the inner diameter surface of the end portion of the bearing outer ring 33, and the inner diameter surface of the inward flange 65 a of the slinger 65 and the outer shoulder portion of the bearing inner ring 32. A labyrinth 66 is provided between the radial surfaces.

  As shown in FIGS. 9 and 10, by providing the labyrinths 64 and 66 between the opposing portions of the bearing outer ring 33 and the bearing inner ring 32, it is possible to prevent leakage of grease that lubricates the inside of the hub bearing 30 to the outside. it can.

  FIG. 11 shows another example of an in-wheel motor-equipped wheel bearing device. In this example, the mounting of the wheel wheel 39 to the hub 31 is a wheel bolt type. That is, the bolt 69 is screw-engaged from the bolt insertion hole 67 formed in each of the wheel wheel 39 and the brake rotor 40 to the screw hole 68 provided in the wheel mounting flange 31 b of the hub 31, and the wheel is tightened. The wheel 39 is fixed.

  As described above, since the wheel wheel 39 is mounted on the wheel bolt type, it is not necessary to secure a space for pulling out the bolt as compared with the hub bolt type shown in FIG. It is possible to reduce the thickness of the bearing device.

In addition, in the example shown in FIG. 11, the pitch circle diameter of the inboard-side rolling element 34 a row that rotatably supports the bearing inner ring 32 among the double row rolling elements 34 a and 34 b provided in the hub bearing 30. D ₁ was greater than the pitch circle diameter _{D 2} of the rolling elements 34b columns on the outboard side for rotatably supporting the hub _{31 (D 1> D 2)} , and rolling elements 34a number of inboard rolling elements 34a column Is larger than the number of outboard side rolling elements 34b.

As described above, the pitch circle diameter D ₁ of the rolling element 34a columns on the inboard side larger than the rolling elements 34b column pitch circle diameter D ₂ on the outboard side, and the rolling elements of the inboard rolling elements 34a column By making the number of 34a larger than the number of outboard side rolling elements 34b, the bearing rigidity can be increased.

  In the embodiment shown in FIG. 1, a planetary gear type reduction gear is shown as the reduction gear 50 that decelerates the rotation of the input shaft 24 and outputs it to the drive axle 26. However, the reduction gear 50 is limited to a planetary gear type. Not. For example, a cycloid reducer may be used.

DESCRIPTION OF SYMBOLS 10 Housing 16 Electric motor 18 Rotor 22 Shaft insertion hole 24 Input shaft 26 Drive axle 26a Large diameter shaft part 27 Opening part 28 Oil seal 30 Hub bearing 31 Hub 31a Small diameter cylindrical part 31c Pilot part 32 Bearing inner ring 33 Bearing outer ring 34a Rolling element 34b Rolling element 39 Wheel wheel 41 Nut 50 Reduction gear 60 Seal ring 61 Cap 62 Hardened layer 63 Slinger 64 Labyrinth 66 Labyrinth 67 Bolt insertion hole 68 Screw hole 69 Bolt

Claims (10)

A housing, an electric motor accommodated in the housing, an input shaft provided on the axis of the rotor of the electric motor and rotating integrally with the rotor, and provided coaxially with the input shaft; A drive axle that is inserted through an opening provided in an end wall of the housing and faces the outside, and a speed reducer that is incorporated in the housing and decelerates rotation of the input shaft to output to the drive axle. An in-wheel type comprising a hub bearing having a hub that rotatably supports the drive axle and transmits the rotation of the drive axle to a wheel, and lubricates the speed reducer with lubricating oil stored in the housing In the bearing device for the motor built-in wheel,
The drive axle has a large-diameter shaft portion disposed in the opening, and the space between the outer diameter surface of the large-diameter shaft portion and the inner diameter surface of the opening of the housing is sealed by incorporating an oil seal. An in-wheel motor built-in wheel bearing device.   The hub bearing is fitted to the driving axle so as not to rotate relative to the drive axle, a bearing inner ring fitted to a small diameter cylindrical portion at an inboard side end portion of the hub, and attached to and detached from an outer surface of the end wall of the housing. A bearing outer ring that is freely mounted and a double row rolling element that is incorporated in the bearing outer ring and rotatably supports the hub and the bearing inner ring, and is screw-engaged with the shaft end of the drive axle. The in-wheel type motor built-in wheel bearing device according to claim 1, wherein a preload is applied to the hub bearing by pressing a bearing inner ring against a shaft end surface of the large-diameter shaft portion by tightening a nut that prevents the hub from being pulled out.   The bearing device for in-wheel type motor built-in wheels according to claim 2 which made open state between a bearing outer ring in said hub bearing and an inboard side facing part of said bearing inner ring.   The in-wheel motor built-in wheel according to claim 3, wherein a seal ring is incorporated between the bearing outer ring and the opposed portion of the opening, and between the small-diameter cylindrical portion of the hub and the opposed portion of the large-diameter shaft portion of the drive axle. Bearing device.   The in-wheel type according to claim 3, wherein a seal ring is incorporated between opposing portions of the bearing outer ring and the opening, and a cap is incorporated in an opening of a cylindrical pilot portion provided at an end on the outboard side of the hub. Bearing device for motor built-in wheels.   The in-wheel motor built-in wheel according to any one of claims 1 to 5, wherein a hardened layer is provided on a surface layer portion by heat-treating a range from an outer diameter surface of the drive axle to a shaft end surface of the large-diameter shaft portion. Bearing device.   A pack in which the oil seal has a pair of radial lips that elastically contact a cylindrical portion of a slinger having an L-shaped cross-section press-fitted into the outer diameter surface of the large-diameter shaft portion, and an axial lip that elastically contacts a flange of the slinger The in-wheel type motor-integrated wheel bearing device according to any one of claims 1 to 6, which is of a type.   The in-wheel motor-equipped wheel bearing device according to claim 3, wherein a labyrinth is provided between opposing portions of the bearing outer ring and the bearing inner ring of the hub bearing.   The wheel wheel mounting to the hub comprises a wheel bolt type in which a bolt is screwed and tightened from a bolt insertion hole formed in the wheel wheel to a screw hole of a flange provided on the outer periphery of the hub. The in-wheel type motor-integrated wheel bearing device according to any one of the preceding claims.   In the double row rolling element row, the pitch circle diameter of the inboard side rolling element row that rotatably supports the bearing inner ring is larger than the pitch circle diameter of the outboard side rolling element row that rotatably supports the hub. Item 10. The bearing device for an in-wheel motor-equipped wheel according to any one of Items 1 to 9.

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