JP2017165267A - In-wheel motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple sealing structure when performing grease lubrication at a spline fitting portion.SOLUTION: An outer ring rotation type bearing is used as the wheel bearing 50 of an in-wheel motor drive device 21, and a speed reduction gear 39 is arranged on the outer diameter side of the wheel bearing 50. The output shaft 36 of the speed reduction gear 39 is externally fitted to a bearing outer ring 53 of the wheel bearing 50, and torque is transmitted between the output shaft 36 and the bearing outer ring 53 via a spline. Grease is interposed in a spline fitting portion 60 between the output shaft 36 and the bearing outer ring 53. A grease filling space 64 is formed communicating with an inboard side end of the spline fitting portion 60, and a seal member 70 is disposed between the output shaft 36 and a housing 22 among members that partition the grease filling space 64.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an in-wheel motor drive device in which, for example, an output shaft of an electric motor and a wheel bearing are connected via a reduction gear.

  In the in-wheel motor drive device, by using a speed reducer, the motor can be downsized to reduce the size and weight of the in-wheel motor drive device as a whole, and to reduce the unsprung weight. This is because the output torque of the motor is proportional to the size and weight of the motor, so that if a motor alone is used to generate the torque necessary for driving the vehicle, a large motor is required. This is because the weight and volume of the motor, which is reduced in the above, exceeds those of the reducer.

By reducing the size and weight of the in-wheel motor drive device, not only can the vehicle weight be reduced, but also by diverting the existing suspension system when the internal combustion engine vehicle and the vehicle body are used together, changes in suspension characteristics and steering characteristics are eliminated, Deterioration of the ride comfort of the vehicle can be prevented. However, in the case where the wheel bearing is arranged in the direction of the extension line of the output shaft of the speed reducer as in the in-wheel motor driving device disclosed in, for example, JP-A-2015-73370 (Patent Document 1), the in-wheel motor driving is performed. The overall axial dimension of the device becomes long and may interfere with existing suspension devices. Therefore, it is necessary to change the design of the suspension device, and the suspension characteristics and the steering characteristics may be deteriorated.

Japanese Patent Laying-Open No. 2015-73370

  As a countermeasure against this, it is conceivable to use a wheel bearing of an outer ring rotating type, arrange a reduction gear on the outer diameter side, externally fit the output shaft of the reduction gear to the bearing outer ring, and couple them together by a spline. . Thereby, since the axial direction length of an in-wheel motor drive device can be shortened, said malfunction can be eliminated.

On the other hand, in the outer ring rotation type wheel bearing, the bearing outer ring is tilted when a turning load or a vertical load is applied. At this time, if the spline of the output shaft and the spline of the bearing outer ring are in an interference-fitted state (press-fit state), the output shaft and the bearing outer ring are integrated, so the output shaft of the reducer also tilts due to the inclination of the bearing outer ring. . For this reason, the tooth surfaces of the gears are in contact with each other in the reduction gear, and the durability of the reduction gear may be reduced.

In order to avoid the above problems, it is preferable to make a clearance fit between the spline of the output shaft and the spline fitting portion of the bearing outer ring. As a result, the relative inclination of the bearing outer ring with respect to the output shaft is allowed, and a part of the inclination of the bearing outer ring is absorbed by the sliding between the spline tooth surfaces. Can be improved. In this case, there is concern about increased vibration due to frequent micro sliding between the tooth surfaces of the spline, abnormal wear of the spline fitting part, or heat generation. Need to intervene.

In order to perform grease lubrication by interposing the grease between the tooth surfaces of the spline fitting portion, it becomes a problem how to avoid grease leakage from the spline fitting portion. Since both the bearing outer ring and the output shaft are rotating members, it is advantageous in terms of cost to use, for example, an O-ring as a seal between the two members. In such a configuration, the bearing outer ring is connected to the inner periphery of the output shaft. When inserting into the outer ring, the inboard side O-ring mounted in the outer peripheral groove of the bearing outer ring may interfere with the female spline, making it difficult to guarantee the sealing performance on the inboard side of the spline fitting portion.

  Accordingly, an object of the present invention is to provide a simple seal structure when grease lubrication is performed at a spline fitting portion using an outer ring rotating type wheel bearing.

  As technical means for achieving the above-mentioned object, the present invention includes a motor, a speed reducer housed in a housing and decelerating and outputting the rotation of the motor, and an outer member having a double row outer race, An inner member having a double row inner race, and a wheel bearing having a double row rolling element disposed between the outer race and the inner race, and the output shaft of the speed reducer as an outer member of the wheel bearing. In the in-wheel motor drive device, wherein the spline is externally fitted, torque is transmitted between the output shaft and the outer member via a spline, and grease is interposed in the spline fitting portion between the output shaft and the outer member. A grease filling space that communicates with the inboard side end of the fitting portion is formed, and a seal member is disposed between the output shaft and the stationary member among the members that define the grease filling space.

  By disposing the seal member between the output shaft that partitions the grease filling space and the stationary member, leakage of grease from the inboard side of the spline fitting portion can be prevented. Further, if a seal member is disposed between the output shaft and the stationary member, the seal member does not interfere with other members when the outer member is assembled into the inner periphery of the output shaft. Therefore, it is possible to guarantee the sealing performance of the seal member, thereby reliably preventing grease leakage from the inboard side of the spline fitting portion.

  The stationary member can be the housing (FIG. 3) or the inner member of a wheel bearing (FIG. 7).

  If a seal member is disposed between the outer member and the inner member among the members forming the grease filling space, the spline fitting portion can be separated from the bearing inner space. Therefore, it is possible to prevent wear powder or the like generated at the spline fitting portion from entering the bearing internal space, and to stabilize the bearing performance.

If a cap is press-fitted into the opening on the outboard side of the outer member, it becomes possible to seal the outboard side of the bearing internal space without increasing the frictional resistance.

If a seal member is disposed between the output shaft and the outer member on the outboard side of the spline fitting portion, it is possible to more reliably prevent grease leakage from the spline fitting portion.

Thus, leakage of the grease supplied to the spline fitting portion is prevented, so that grease lubrication can be stably performed between the tooth surfaces even when the spline fitting portion is loosely fitted. Therefore, even when the outer member is tilted due to moment load or the like, a part of it is absorbed by sliding between the tooth surfaces at the spline fitting part, and the inclination of the output shaft following the inclination of the outer member is suppressed. be able to. Therefore, the durability of the reduction gear can be improved.

  According to the present invention, grease leakage from the inboard side of the spline fitting portion can be reliably prevented. Therefore, grease can be stably held between the tooth surfaces of the spline fitting part for a long period of time, and even when an outer ring type wheel bearing is used, abnormal wear, heat generation, or vibration at the spline fitting part Can be prevented.

It is the front view which looked at the in-wheel motor drive device arrange | positioned in the inner space of the wheel from the outboard side. FIG. 2 is a cross-sectional view taken along a line P-P passing through a motor center Oa, an intermediate shaft center O1, and an axle center Ob in FIG. It is sectional drawing which expands and shows the surrounding structure (1st Embodiment) of the wheel bearing of FIG. It is sectional drawing which expands and shows a comparative example. It is sectional drawing which shows 2nd Embodiment. It is sectional drawing which shows 3rd Embodiment. It is sectional drawing which shows 4th Embodiment. It is sectional drawing which shows 5th Embodiment. It is a top view which shows schematic structure of the electric vehicle carrying an in-wheel motor drive device. FIG. 10 is a rear sectional view showing the electric vehicle of FIG. 9.

  An embodiment of an in-wheel motor drive device according to the present invention will be described in detail with reference to the drawings.

  FIG. 9 is a schematic plan view of the electric vehicle 11 on which the in-wheel motor drive device 21 is mounted, and FIG. 10 is a schematic cross-sectional view of the electric vehicle 11 as viewed from the rear.

  As shown in FIG. 9, the electric vehicle 11 includes a chassis 12, a front wheel 13 as a steering wheel, a rear wheel 14 as a driving wheel, and an in-wheel motor drive device 21 that transmits driving force to the rear wheel 14. Equip. As shown in FIG. 10, the rear wheel 14 is accommodated in a wheel housing 15 of the chassis 12 and is fixed to a lower portion of the chassis 12 via a suspension device (suspension) 16.

  The suspension device 16 supports the rear wheel 14 by a suspension arm that extends 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. A stabilizer that suppresses the inclination of the vehicle body during turning or the like is provided at a connecting portion of the left and right suspension arms. The suspension device 16 is an independent suspension type in which the left and right wheels are independently moved up and down in order to improve the followability to the road surface unevenness and efficiently transmit the driving force of the rear wheel 14 to the road surface.

  In the electric vehicle 11, the in-wheel motor drive device 21 that drives the left and right rear wheels 14 is provided inside the wheel housing 15, thereby eliminating the need to provide a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 12. Therefore, there is an advantage that a wide cabin space can be secured and the rotation of the left and right rear wheels 14 can be controlled.

  Before describing the characteristic configuration of this embodiment, the overall configuration of the in-wheel motor drive device 21 will be described with reference to FIGS. 1 and 2. In the following description, in a state where the in-wheel motor drive device 21 is mounted on the vehicle, the side closer to the outside of the vehicle is referred to as the outboard side, and the side closer to the center is referred to as the inboard side.

  FIG. 1 is a front view of an in-wheel motor drive device 21 arranged in the inner space of the rear wheel 14 as viewed from the outboard side. FIG. 2 is a cross-sectional view taken along the line P-P passing through the motor center Oa, the intermediate shaft center O1, and the axle center Ob in FIG.

  As shown in FIGS. 1 and 2, the in-wheel motor drive device 21 includes a motor part A that generates a driving force, a speed reducer part B that decelerates and outputs the rotation of the motor part A, and a speed reducer part B. And a wheel bearing portion C that transmits the output to a rear wheel as a drive wheel. The motor part A, the speed reducer part B, and the wheel bearing part C are each accommodated in the housing 22. As shown in FIG. 2, the housing 22 may be a single-piece structure or a splittable structure.

  As shown in FIG. 2, the motor unit A includes a stator 23 that is fixed to the housing 22, a rotor 24 that is arranged to face the inner side in the radial direction of the stator 23 with a gap, and an inner side in the radial direction of the rotor 24. Thus, a radial gap type electric motor 26 having a motor rotating shaft 25 that rotates integrally with the rotor 24 is formed. The motor rotating shaft 25 can rotate at a high speed of about 10,000 to 1000 rotations per minute. The stator 23 is configured by winding a coil around a magnetic core, and the rotor 24 is configured by a permanent magnet or the like.

  The motor rotating shaft 25 is connected to the housing 22 at one end in the axial direction (left side in FIG. 2) by the rolling bearing 40 and at the other end in the axial direction (right side in FIG. 2) by the rolling bearing 41. Each is supported rotatably.

  The reduction gear unit B includes an input gear 30, a first intermediate gear 31 and a second intermediate gear 32 as a plurality of intermediate gears, and an output gear 35. The input gear 30 integrally has an input shaft 30a, and the input shaft 30a is connected to the motor rotating shaft 25 coaxially by spline fitting (including serration fitting, the same applies hereinafter). The first intermediate gear 31 is formed integrally with the intermediate shaft S1, and the second intermediate gear 32 is connected to the first intermediate shaft S1 by spline fitting. The output gear 35 is formed integrally with a hollow output shaft 36.

  The input shaft 30a, the intermediate shaft S1, and the output shaft 36 are arranged in parallel to each other. The input shaft 30a is supported by the rolling bearings 42 and 43, the intermediate shaft S1 by the rolling bearings 44 and 45, and the output shaft 36 by the rolling bearings 48 and 49, respectively.

  In the reduction gear portion B, the input gear 30 and the first intermediate gear 31 are engaged with each other, and the second intermediate gear 32 and the output gear 35 are engaged with each other. The number of teeth of the first intermediate gear 31 is greater than the number of teeth of the input gear 30 and the second intermediate gear 32. Further, the number of teeth of the output gear 35 is larger than the number of teeth of the second intermediate gear 32. From the above configuration, the parallel shaft gear reducer 39 configured to decelerate the rotational motion of the motor rotating shaft 25 in two stages is configured.

  In the present embodiment, helical gears are used as the input gear 30, the intermediate gears 31 and 32, and the output gear 35 that constitute the speed reducer 39. Helical gears are effective in that the number of teeth engaged simultaneously increases and the tooth contact is dispersed, so that the sound is quiet and torque fluctuation is small. In consideration of the meshing ratio of gears, the limit number of rotations, etc., it is preferable to set the modules of each gear to about 1-3.

  The wheel bearing portion C includes an outer ring rotation type wheel bearing 50. The wheel bearing 50 includes an axle 51, a bearing inner ring 52 fitted and fixed to an outer peripheral surface of the axle 51 on the outboard side, a bearing outer ring 53 as an outer member disposed on the outer peripheral side of the axle 51, and a bearing A double row inner race 54 formed on the outer peripheral surface of the inner ring 52 and the outer peripheral surface of the axle 51, a double row outer race 55 formed on the inner peripheral surface of the bearing outer ring 53, and the inner race 54 and the outer race 55 are disposed. In addition, a double-row angular contact ball bearing including a plurality of balls 56 as rolling elements and a cage (not shown) that holds each ball 56 is provided. In this embodiment, the bearing inner ring 52 and the axle 51 constitute an inner member having a double-row inner race 54 on the outer periphery.

  A cylindrical surface large-diameter portion 51 a that fits with the inner peripheral surface of the housing 22 is formed at the inboard side end of the axle 51. On the outboard side of the large-diameter portion 51a, a diameter-expanded portion 51b that gradually increases in diameter toward the inboard side is formed. Further, a male screw portion 51 c is formed at the shaft end of the axle 51 on the outboard side. By screwing and tightening the nut 58 to the male thread portion 51c, separation of the wheel bearing 50 is prevented and a preload is applied to the inside of the bearing.

A flange portion 53 a for attaching a wheel is formed at an end portion on the outboard side of the bearing outer ring 53. A brake disc 59 and a rear wheel wheel are attached to the flange portion 53a using hub bolts (illustration of the wheel and hub bolt is omitted). A cylindrical portion 53b disposed on the inner periphery of the hollow output shaft 36 of the speed reducer 39 is formed on the inboard side of the flange portion 53a of the bearing outer ring 53. A spline fitting portion 60 is formed by fitting a male spline formed on the outer peripheral surface of the cylindrical portion 53 b and a female spline formed on the inner peripheral surface of the output shaft 36, and the bearing outer ring 53 is formed by the spline fitting portion 60. And the output shaft 36 are coupled so that torque can be transmitted. Thereby, the output of the reduction gear part B is transmitted to the rear wheels.

  The in-wheel motor drive device 21 is attached to the suspension device of the vehicle body by attaching the large diameter portion 51a formed at the inboard side end portion of the axle 51 and the housing 22 to the knuckle. At this time, as shown in FIG. 1, the center O1 of the intermediate shaft S1 is offset from a line connecting the center Oa (motor center) of the motor 26 and the center Ob (axle center) of the axle 51 in a direction orthogonal to the line. And between the motor center Oa and the axle center Ob. FIG. 1 illustrates the case where the in-wheel motor drive device 21 is attached to the vehicle body in such a direction that the line connecting the motor center Oa and the axle center Ob is substantially vertical.

  Since the in-wheel motor drive device 21 is housed in the wheel housing 15 (see FIG. 10) and becomes an unsprung load, it is essential to reduce the size and weight. By combining the parallel shaft gear reducer 39 with the electric motor 26, it is possible to use a small electric motor 26 of low torque and high rotation type. For example, when the parallel shaft gear reducer 39 having a reduction ratio of 11 is used, the electric motor 26 can be reduced in size by using the electric motor 26 that rotates at a high speed of about ten thousand rotations per minute. Thereby, the compact in-wheel motor drive device 21 can be realized, and the electric vehicle 11 excellent in running stability and NVH characteristics can be obtained while suppressing the unsprung weight.

[First Embodiment]
Next, a first embodiment of the characteristic configuration of the present invention will be described with reference to FIG. FIG. 3 is an enlarged cross-sectional view showing a peripheral portion of the wheel bearing 50 in FIG.

  The fitting of the spline fitting portion 60 that couples the output shaft 36 of the reduction gear 39 and the bearing outer ring 53 is a clearance fitting state having a gap between the tooth surfaces (the tooth bottom and the tooth tip of the spline fitting portion 60). There is also a gap). Further, grease is interposed between the tooth surfaces facing each other of the spline fitting portion 60. For example, grease is applied to one or both of the spline of the output shaft 36 and the bearing outer ring 53, and then the bearing outer ring 53 is inserted into the inner periphery of the output shaft 36, whereby the tooth surface of the spline fitting portion 60 is separated. Grease can be interposed between the two.

  In the present invention, a grease-filled space 64 filled with grease that communicates with the inboard side end of the spline fitting portion 60 is formed in and around the wheel bearing 50. The grease filling space 64 is a space defined by members such as the output shaft 36, the housing 22, the axle 51, the bearing inner ring 52, and the bearing outer ring 53, and mainly the bearing inner space 62 of the wheel bearing 50 and the axle 51. It is formed by an axle outer peripheral space 63 facing the enlarged diameter portion 51b. The bearing inner space 62 here is a space formed by the inner peripheral surface of the bearing outer ring 53 and the outer peripheral surface of the inner member facing the bearing outer ring 53 (the outer peripheral surface of the axle 51 and the outer peripheral surface of the bearing inner ring 52). . In addition, the dotted pattern in FIG. 3 represents the presence area | region of grease.

In the present invention, the seal member 70 is disposed between the output shaft 36 that defines the grease filling space 64 and the stationary member. FIG. 3 shows a case where a seal member 70 is disposed between the output shaft 36 and the housing 22 that houses the speed reducer 39 as a specific example. For example, an oil seal can be used as the seal member 70. The oil seal is a ring-shaped spring 72 attached to the outer periphery of the seal lip and presses the tip of the seal lip against the outer peripheral surface of the shaft to obtain a sealing effect. The oil seal 70 is press-fitted and fixed to the inner peripheral surface of the housing 22, and the tip of the seal lip is brought into contact with the outer peripheral surface of the end portion on the inboard side of the output shaft 36. A sealing effect can be reliably obtained.

In the in-wheel motor drive device 21, lubricating oil fed by a rotary pump (not shown) is supplied to each part for cooling the motor 26 and lubricating and cooling the speed reducer 39. Lubricating oil used for cooling and lubricating each part accumulates at the bottom of the internal space of the speed reducer part B as shown by cross hatching in FIG. The lubricating oil collected in the lubricating oil reservoir 61 is sucked up by the rotary pump and supplied again to each part.

Between the outer peripheral surface of the end portion on the outboard side of the output shaft 36 and the housing 22, the seal member 71 made of the above oil seal or the like is disposed. By this seal member 71 and the above-described seal member 70, the lubricating oil reservoir 61 is sealed on both the outboard side and the inboard side, and leakage of the lubricating oil to the grease filling space 64 and the outside is prevented.

Further, in order to prevent grease from leaking from the bearing internal space 62, the opening on the outboard side of the bearing internal space 62 is sealed with a seal member 73 made of an oil seal or the like.

On the outboard side from the spline fitting portion 60, a seal member 74 seals between the inner peripheral surface of the output shaft 36 and the outer peripheral surface of the cylindrical portion 53 b of the bearing outer ring 53. Since both the output shaft 36 and the bearing outer ring 53 are rotating members, and relative rotation does not occur between the two members, an O-ring is sufficient as the sealing member 74 instead of the oil seal described above. A seal member 75 is also disposed between the outer peripheral surface of the large-diameter portion 51 a of the axle 51 and the inner peripheral surface of the housing 22. Since both the axle 51 and the housing 22 are stationary members and relative rotation does not occur between the two members, an O-ring is sufficient as the seal member 75.

From the above configuration, each of the spline fitting portion 60, the lubricating oil reservoir 61, and the grease filling space 64 is in a sealed state (as described above, the end portion on the inboard side of the spline fitting portion 60 is the grease filling space. 64). Further, the lubricant reservoir 61 and the grease filling space 64 are separated from each other by the seal member 70.

As described above, since both the inboard side and the outboard side of the spline fitting portion 60 are sealed, grease leakage from the spline fitting portion 60 can be reliably prevented. Therefore, the spline fitting portion 60 is in a clearance fit state, and grease lubrication can be performed between the tooth surfaces. Thereby, a part of the inclination of the bearing outer ring 53 due to the moment load or the like is absorbed by the sliding of the tooth surfaces of the spline fitting portion 60, and the inclination of the output shaft 36 accompanying the inclination of the bearing outer ring 53 is reduced. A decrease in durability of the portion 39 can be suppressed. Therefore, the reduction gear 39 can be disposed on the outer diameter side of the outer ring rotating type wheel bearing 50 (see FIG. 2), and the axial length of the in-wheel motor drive device 21 can be shortened. It becomes possible.

Moreover, since the lubricating oil reservoir 61 and the grease filling space 64 can be completely separated, the bearing outer ring 53 is inserted into the inner periphery of the reduction gear portion B filled with the lubricating oil in advance, and the wheel bearing 50 is assembled. Thus, the assembly work of the in-wheel motor drive device 21 can be simplified. In addition, since the same grease can be filled into the spline fitting portion 60 and the bearing internal space 62, simplification of the grease application process can be avoided.

If only the spline fitting portion 60 is sealed, the O-ring is provided between the inner peripheral surface of the output shaft 36 and the outer peripheral surface of the cylindrical portion 53b of the bearing outer ring 53 on the inboard side as well as the outboard side. Arrangement is first considered. However, as shown in FIG. 3, the outer peripheral surface 53b1 (small diameter portion) of the cylindrical portion 53b in this region is smaller in diameter than the root diameter, and the gap width between the inner peripheral surface of the output shaft 36 is increased. Therefore, it is necessary to use a thick O-ring. In this case, if the O-ring is mounted on the small-diameter portion 53b1 and the bearing outer ring 53 is inserted into the inner peripheral surface of the output shaft 36 during assembly, the O-ring may interfere with the female spline of the output shaft 36 and may not be mounted correctly. Therefore, it is difficult to ensure the sealing performance on the inboard side of the spline fitting portion 60.

As an alternative, as shown in FIG. 4, oil seals 77 and 78 may be press-fitted and fixed to the inner peripheral surface of the housing 22, and the tips of the seal lips may be brought into contact with the outer peripheral surface of the bearing outer ring 53. In this case, at the time of assembly, the bearing outer ring 53 can be inserted into the inner periphery of the output shaft 36 in a state where the oil seal 77 on the inboard side is press-fitted and fixed to the housing. Can be guaranteed. However, in such a configuration, the spline fitting portion 60 cannot be separated from the lubricating oil reservoir 61, and the lubricating oil in the lubricating oil reservoir 61 enters the spline fitting portion 60. Further, in order to secure an installation space for the oil seal 77 on the inboard side, the bearing outer ring 53 must be extended to the inboard side, and it is necessary to cut the meat of the enlarged diameter portion 51b accordingly, so that the axle 51 There is also a problem that the strength decreases.

On the other hand, if it is the structure of this invention shown in FIG. 3, all said problems can be eliminated. That is, when inserting the bearing outer ring 53 into the inner periphery of the output shaft 36 at the time of assembly, there is no possibility that the inboard side seal member 70 interferes with other members. It is easy to guarantee. Further, the spline fitting portion 60 can be completely separated from the lubricating oil reservoir 61.

[Second Embodiment]
FIG. 5 illustrates a second embodiment of the present invention.
In 1st Embodiment shown in FIGS. 1-3, while forming the inner race 54 of the inboard side in the outer peripheral surface of the axle 51 among the double row inner races 54 as the wheel bearing 50, it is the outer board side. Although the case where a so-called third generation in which the inner race 54 is formed on the outer peripheral surface of the bearing inner ring 52 is used has been exemplified, in the second embodiment shown in FIG. The so-called second generation is used, in which two bearing inner rings 52a and 52b are press-fitted and fixed, and inner races 54 are formed on the outer peripheral surfaces of both bearing inner rings 52a and 52b, respectively. Wheel bearings 50 can be used). In this second generation wheel bearing 50, an inward member is formed by the axle 51 and the two bearing inner rings 52a and 52b. Except for the above points, the configuration and operational effects of the second embodiment are the same as the configuration and operational effects of the first embodiment, so redundant description will be omitted.

[Third Embodiment]
FIG. 6 shows a third embodiment of the present invention.
In the third embodiment, the seal member 73 for sealing the outboard side of the bearing internal space 62 is omitted in the first embodiment shown in FIGS. The cap 80 is press-fitted and fixed to the part. Thus, by using the cap 80 instead of the contact-type seal member 73 to prevent grease leakage, it is possible to reduce the frictional resistance and reduce the torque of the wheel bearing 50. If there is no particular problem, the seal member 73 and the cap 80 may be used in combination without omitting the seal member 73 (see FIG. 8). Except for the above points, the configuration and operational effects of the third embodiment are the same as the configuration and operational effects of the first embodiment, and therefore redundant description is omitted.

[Fourth Embodiment]
FIG. 7 shows a fourth embodiment of the present invention.
In the embodiment shown in FIGS. 1 to 3, the grease filling space 64 is sealed by the seal member 70 disposed between the inboard side end portion of the output shaft 36 and the housing 22, but the fourth embodiment shown in FIG. In the embodiment, the grease filling space 64 is sealed with a seal member 81 disposed between the output shaft 36 and the axle 51 (stationary member). Specifically, the seal member 81 is press-fitted into the inner peripheral surface of the inboard side end portion of the output shaft 36, and the seal lip is brought into contact with the outer peripheral surface of the axle 51 to seal the grease filling space 64. Also with this configuration, grease leakage from the inboard side of the spline fitting portion 60 can be prevented as in the first embodiment.

In this case, the lubricating oil reservoir 61 can be sealed by disposing the seal member 70 made of an oil seal or the like between the inboard side end of the output shaft 36 and the housing 22. As described above, in the fourth embodiment, the sealing of the grease filling space 64 and the sealing of the lubricating oil reservoir 61 are performed using the separate sealing members 81 and 70, and in this respect, the single sealing member 70 lubricates. The configuration is different from that of the first embodiment in which the oil reservoir 61 and the grease filling space 64 are separated.

In the fourth embodiment shown in FIG. 7, the outboard side of the bearing internal space 62 of the wheel bearing 57 is sealed using the cap 80, but a seal member 73 such as an oil seal is used as in the first embodiment. (See FIG. 3). Except for the above points, the configuration and operational effects of the fourth embodiment are the same as the configuration and operational effects of the first embodiment, so redundant description will be omitted.

[Fifth Embodiment]
FIG. 8 shows a fifth embodiment of the present invention.
In the fifth embodiment, the inboard side of the bearing internal space 62 is sealed, and the bearing internal space 62 and the spline fitting portion 60 are separated. Specifically, the seal member 82 is press-fitted into the inner peripheral surface of the end portion on the inboard side of the bearing outer ring 53, and the seal lip is brought into contact with the outer peripheral surface of the axle 51. In this case, only the axle outer peripheral space 63 becomes a grease filling space that communicates with the inboard side end portion of the spline fitting portion 60. With such a configuration, even when wear powder is generated by sliding between the tooth surfaces at the spline fitting portion 60, it is possible to prevent the wear powder from entering the wheel bearing 50. Also, different greases can be used for the spline fitting portion 60 and the bearing internal space 62.

In the fifth embodiment, a sealing member 83 made of an oil seal or the like is disposed between the housing 22 and the bearing outer ring 53 on the outboard side, thereby further enhancing the sealing effect of the lubricating oil and grease. . Except for the above points, the configuration and operational effects of the fifth embodiment are the same as the configuration and operational effects of the first embodiment, so redundant description will be omitted.

  In the above description of each embodiment, the radial gap type electric motor 26 is exemplified as the motor unit A, but a motor having an arbitrary configuration is applicable. For example, an axial gap type electric motor including a stator fixed to a housing and a rotor arranged so as to face the inner side in the axial direction of the stator with a gap may be used. Moreover, although the case where a parallel axis | shaft speed reducer was used as the speed reducer 39 was illustrated, the structure of the speed reducer 39 is arbitrary, For example, the speed reducer containing a planetary gear mechanism can also be used. Further, the number of speed reduction stages of the speed reducer 39 is arbitrary, and the speed can be reduced to three or more stages.

  In the above description, the case where the motor unit A is supplied with electric power to drive the motor unit and the power from the motor unit A is transmitted to the rear wheel 14 is shown. On the contrary, the vehicle decelerates. When driving down or going down a hill, the power from the rear wheel 14 side is converted into high-rotation low-torque rotation by the reducer B and transmitted to the motor A, and the motor A generates power. Good. Furthermore, the electric power generated here may be stored in a battery and used later for driving the motor unit A or for operating other electric devices provided in the vehicle.

  In the embodiment described above, as illustrated in FIGS. 9 and 10, the electric vehicle 11 having the rear wheel 14 as the driving wheel is illustrated, but the front wheel 13 may be the driving wheel, and the vehicle is a four-wheel driving vehicle. Also good. In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and includes, for example, a hybrid vehicle.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

21 In-wheel motor drive device 26 Motor 30 Input gear 30a Input shaft 35 Output gear 36 Output shaft 39 Reduction gear 50 Wheel bearing 51 Axle (inward member)
52 Bearing inner ring (inner member)
53 Bearing outer ring (outer member)
54 Inner race 55 Outer race 56 Rolling element 60 Spline fitting portion 61 Lubricating oil reservoir 62 Bearing inner space 63 Axle outer peripheral space 64 Grease filling space 70 Seal member (oil seal)
71 Seal member (oil seal)
73 Seal member (oil seal)
74 Seal member (O-ring)
75 Seal member (O-ring)
80 Cap 81 Seal member 82 Seal member

Claims (7)

A motor, a speed reducer housed in a housing and decelerating and outputting the rotation of the motor, an outer member having a double row outer race, an inner member having a double row inner race, and an outer race and an inner race A wheel bearing having a double-row rolling element disposed between, and the output shaft of the speed reducer is externally fitted to the outer member of the wheel bearing, and a spline is interposed between the output shaft and the outer member. In the in-wheel motor drive device that performs torque transmission and interposes grease in the spline fitting portion between the output shaft and the outer member,
A grease filling space that communicates with an inboard side end of the spline fitting portion is formed, and a seal member is disposed between an output shaft and a stationary member among members that define the grease filling space. Wheel motor drive device.   The in-wheel motor drive device according to claim 1, wherein the stationary member is the housing.   The in-wheel motor drive device according to claim 1, wherein the stationary member is an inward member of a wheel bearing.   The in-wheel motor drive device of any one of Claims 1-3 which has arrange | positioned the sealing member between the outer member and the inner member among the members which form the said grease filling space. The in-wheel motor drive device according to any one of claims 1 to 4, wherein a cap is press-fitted into an opening on the outboard side of the outer member. The in-wheel motor drive device of any one of Claims 1-5 which has arrange | positioned the sealing member between the said output shaft and an outer member on the outboard side rather than the said spline fitting part. The in-wheel motor drive device according to any one of claims 1 to 6, wherein the spline fitting portion is a clearance fit.

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