WO2016002571A1

WO2016002571A1 - In-wheel motor drive device

Info

Publication number: WO2016002571A1
Application number: PCT/JP2015/067971
Authority: WO
Inventors: 朋久魚住; 俊明圓増; 鈴木　健一
Original assignee: Ntn株式会社; 朋久魚住; 俊明圓増; 鈴木　健一
Priority date: 2014-07-03
Filing date: 2015-06-23
Publication date: 2016-01-07
Also published as: JP2016014445A

Abstract

　The present invention addresses the problem of providing an in-wheel motor drive device that is small and lightweight and that has excellent lubrication performance and improved durability. The invention provides an in-wheel motor drive device equipped with a lubrication mechanism in the interior, the in-wheel motor drive device characterized in that the outer periphery of a torque transmission part of a reduction gear input shaft (25) is fitted with the inner periphery of the torque transmission part of a motor rotating shaft (24), lubricating oil channels (24a), (25c) constituting part of the lubrication mechanism are formed in the respective interiors of the motor rotating shaft (24) and the reduction gear input shaft (25), and a hollow pipe member (80), (80') forming the lubricating oil channel (24a) is fitted into the motor rotating shaft (24).

Description

In-wheel motor drive device

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

A conventional in-wheel motor drive device is described in, for example, Japanese Patent Application Laid-Open No. 2011-189919 (Patent Document 1). The in-wheel motor drive device described in the publication is disposed between a motor unit that generates a driving force, a wheel bearing unit that is connected to a wheel, and the motor unit and the wheel bearing unit. And a speed reducer that decelerates the rotation and transmits it to the wheel bearing.

The above-mentioned in-wheel motor drive device employs a low-torque, high-rotation type motor for the motor unit from the viewpoint of making the device compact. On the other hand, since a large torque is required for driving the wheel in the wheel bearing portion, a cycloid reduction gear that is compact and obtains a high reduction ratio is employed for the reduction portion.

The motor unit includes a stator fixed to the casing, a rotor disposed at a position facing the inner side of the stator with a radial gap, and a motor rotating shaft connected and fixed to the inner side of the rotor and integrally rotated with the rotor. It is a radial gap motor. The motor rotating shaft having a hollow structure is supported by a casing so that both ends in the axial direction are rotatable by a pair of rolling bearings.

The speed reducer to which the cycloid speed reducer is applied is a speed reducer input shaft having a pair of eccentric parts, a pair of curved plates arranged in the eccentric parts, and an outer peripheral surface of the curved plate to rotate on the curved plates. A plurality of outer peripheral engagement members to be generated and a plurality of inner pins that transmit the rotation of the curved plate to the reduction gear output shaft are mainly configured. The motor rotation shaft described above is connected to the reduction gear input shaft by a spline.

This in-wheel motor drive device is provided with a lubrication mechanism that supplies lubricating oil for cooling and lubrication of the motor unit and the speed reduction unit. This lubrication mechanism is mainly composed of a circulating oil passage, a lubricating oil supply port, a lubricating oil discharge port, a lubricating oil reservoir, and a rotary pump. There are lubricating oil passages at the shaft centers of the motor rotation shaft and the reduction gear input shaft. Is formed.

JP2011-189919A

By the way, in the above-described in-wheel motor drive device, the motor rotation shaft in which the lubricating oil passage is formed and the speed reducer input shaft are spline-fitted and torque transmission is performed. Lubricating oil flowing in from the shaft end of the motor rotating shaft cools the motor rotor from the lubricating oil passage in the shaft center of the motor rotating shaft through the lubricating oil supply port, and is ejected to the stator and the shaft center of the speed reducer input shaft. The oil flows into the lubricating oil passage and is divided into a passage for lubricating and cooling the speed reduction portion.

減速 The reduction gear input shaft is splined (including serrations; the same shall apply hereinafter) on the outer diameter, so it is difficult to reduce the thickness of the input shaft. In addition, since a spline is also formed on the motor rotation shaft, it is necessary to have a structure in which the spline is penetrated with a hole diameter larger than the spline large diameter in manufacturing. Therefore, the hole diameter of the lubricating oil passage between the motor rotation shaft and the reduction gear input shaft is It is very different, and a step is generated at the connecting portion. As a result, the lubricating oil that has flowed into the motor rotation shaft is blocked by the previous stage that flows into the lubricating oil passage of the shaft center of the reduction gear input shaft. Therefore, it has been found that the lubricating oil is difficult to be supplied to the speed reducer in the low rotation range.

On the other hand, as a change in the structure of the torque transmission part (spline), a structure in which the motor rotating shaft side is a male spline and the speed reducer input shaft side is a female spline is conceivable. I found it difficult because there was a limit to expansion.

The present invention has been proposed in view of the above-described problems, and an object thereof is to provide an in-wheel motor drive device that is small and light, has excellent lubrication performance, and has improved durability.

As technical means for achieving the above-described object, the present invention includes a motor unit, a speed reduction unit, a wheel bearing unit, and a casing, and the motor unit is fixed to the casing; A motor rotating shaft that is rotatably supported by the casing via a plurality of rolling bearings, and a rotor mounted on the motor rotating shaft, and the motor rotating shaft of the motor unit is a speed reducer input shaft of the speed reducing unit The in-wheel motor drive is provided with a lubrication mechanism internally connected to the reducer output shaft, wherein the wheel bearing portion is connected to the reducer output shaft. In the apparatus, an outer periphery of the torque transmission unit of the speed reducer input shaft is fitted to an inner periphery of the torque transmission unit of the motor rotation shaft, and a lubricating oil path constituting a part of the lubrication mechanism includes the motor rotation shaft. And said decrease Is formed within each of the machine input shaft, a hollow pipe member forming the lubricating oil passage to the motor rotary shaft, characterized in that it is fitted.

With the above configuration, it is possible to realize an in-wheel motor drive device that is small and light, has excellent lubrication performance, and has improved durability. In particular, the lubricating oil supplied from the lubricating oil passage of the motor rotating shaft can be effectively allowed to flow into the speed reducer by the hollow pipe member even in the low rotation range.

Specifically, it is preferable that the inner diameter of the hollow pipe member and the inner diameter of the lubricating oil passage of the reduction gear input shaft are set to substantially the same size. This eliminates the step between the inner diameter of the hollow pipe member forming the lubricating oil path of the motor rotating shaft and the lubricating oil path of the speed reducer input shaft, and reduces the speed reducer input shaft from the lubricating oil path of the motor rotating shaft even in the low speed range. The lubricating oil can effectively flow into the lubricating oil passage.

By forming the lubricating oil supply port in the above-mentioned hollow pipe member in the radial direction and also forming the lubricating oil supply port in the radial direction on the motor rotation shaft, the lubricating oil is effective for cooling the rotor and stator of the motor unit. Can be supplied automatically.

It is preferable to form a circumferential groove in the outer periphery of the lubricating oil supply port of the hollow pipe member. Thereby, even when the phases of the lubricating oil supply port of the hollow pipe member and the lubricating oil supply port of the motor rotating shaft are shifted, a communication structure that does not hinder the supply of the lubricating oil can be achieved.

Also, by making one of the lubricating oil supply port of the hollow pipe member and the lubricating oil supply port of the motor rotating shaft larger than the other, supplying the lubricating oil supply port of the hollow pipe member and the lubricating oil of the motor rotating shaft. Even when the phases of the ports are shifted, a communication structure that does not hinder the supply of the lubricating oil can be achieved.

In order to make the phases of the lubricating oil supply port of the hollow pipe member and the lubricating oil supply port of the motor rotating shaft coincide with each other, and for that purpose, a phase matching engagement portion is provided between the hollow pipe member and the motor rotating shaft. It is preferable. Thereby, the lubricating oil for cooling the rotor and stator of a motor part can be supplied smoothly.

It is preferable that the hollow pipe member and the motor rotation shaft have a fitting structure having a tightening margin at the shaft end. Thereby, the fitting assembly property of a hollow pipe member and a motor rotating shaft can be made easy.

According to the in-wheel motor drive device of the present invention, it is possible to realize an in-wheel motor drive device that is small and light, has excellent lubrication performance, and has improved durability. In particular, the lubricating oil supplied from the lubricating oil passage of the motor rotating shaft can be effectively allowed to flow into the speed reducer by the hollow pipe member even in the low rotation range.

It is a figure which shows the in-wheel motor drive device which concerns on one Embodiment of this invention. FIG. 2 is a cross-sectional view taken along the line OO in FIG. It is explanatory drawing which shows the load which acts on the curve board of FIG. It is a cross-sectional view of the rotary pump of FIG. It is the longitudinal cross-sectional view which expanded the peripheral part of the torque transmission part of the reduction gear input shaft of FIG. 1, and a motor rotating shaft. It is the longitudinal cross-sectional view which expanded the motor rotating shaft which fitted the hollow pipe member. It is the figure which expanded the D section of FIG. 6a. It is the longitudinal cross-sectional view which expanded the hollow pipe member. It is a longitudinal cross-sectional view which shows the modification of a hollow pipe member. It is a top view of the electric vehicle carrying the in-wheel motor drive device of FIG. FIG. 10 is a rear sectional view of the electric vehicle of FIG. 9.

FIG. 9 is a schematic plan view of an electric vehicle 11 equipped with an in-wheel motor drive device 21 according to an embodiment of the present invention, 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 an in-wheel motor drive device that transmits drive power to the chassis 12, front wheels 13 as steering wheels, rear wheels 14 as drive wheels, and left and right rear wheels 14. 21. As shown in FIG. 10, the rear wheel 14 is accommodated in the wheel housing 12a of the chassis 12, and is fixed to the lower portion of the chassis 12 via a suspension device (suspension) 12b.

The suspension device 12b supports the rear wheel 14 by a suspension arm extending left and right, and suppresses vibration of the chassis 12 by absorbing vibration received by the rear wheel 14 from the ground by a strut including a coil spring and a shock absorber. Furthermore, a stabilizer that suppresses the inclination of the vehicle body during turning or the like is provided at a connecting portion of the left and right suspension arms. It is desirable that the suspension device 12b be an independent suspension type in which left and right wheels can be moved up and down independently in order to improve followability to road surface unevenness and efficiently transmit the driving force of the driving wheels to the road surface. .

In the electric vehicle 11, by providing the in-wheel motor drive device 21 for driving the left and right rear wheels 14 inside the wheel housing 12a, it is not necessary to provide a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 12. Therefore, it has the advantages that a large cabin space can be secured and the rotation of the left and right drive wheels can be controlled respectively.

In order to improve the running stability and NVH characteristics of the electric vehicle 11, it is necessary to suppress the unsprung weight. In addition, in-wheel motor drive device 21 is required to be downsized in order to secure a wider cabin space. Therefore, as shown in FIG. 1, an in-wheel motor drive device 21 according to the present embodiment is employed.

An in-wheel motor drive device 21 according to an embodiment of the present invention will be described with reference to FIGS. 1 is a schematic longitudinal sectional view of an in-wheel motor drive device 21, FIG. 2 is a transverse sectional view taken along line OO in FIG. 1, FIG. 3 is an explanatory view showing a load acting on a curved plate, and FIG. FIG. 5 is an enlarged longitudinal sectional view of a peripheral portion of the torque transmission portion of the reduction gear input shaft and the motor rotation shaft, FIG. 6a is an enlarged longitudinal sectional view of the motor rotation shaft fitted with a hollow pipe member, and FIG. 6b. FIG. 6A is an enlarged view of a portion D in FIG. 6A, and FIG. 7 is an enlarged longitudinal sectional view of a hollow pipe member. Before describing the characteristic configuration of the in-wheel motor drive device according to the present embodiment, the overall configuration will be described.

As shown in FIG. 1, the in-wheel motor drive device 21 includes a motor unit A that generates a driving force, a deceleration unit B that decelerates and outputs the rotation of the motor unit A, and an output from the deceleration unit B as driving wheels. 14 (see FIG. 10), and the motor part A and the speed reduction part B are housed in the casing 22 and are housed in the wheel housing 12a of the electric vehicle 11 as shown in FIGS. It is attached. In the present embodiment, the casing 22 has a structure that can be divided into the motor part A and the speed reduction part B, and is fastened with bolts. In the present specification and claims, the casing 22 refers to both a casing part in which the motor part A is accommodated and a casing part in which the speed reduction part B is accommodated.

The motor part A includes a stator 23a fixed to the casing 22, a rotor 23b disposed at a position facing the inner side of the stator 23a with a radial gap, and an inner side of the rotor 23b that is connected and fixed to be integrated with the rotor 23b. A radial gap motor including a rotating motor rotating shaft 24.

The motor rotating shaft 24 having a hollow structure is fitted and fixed to the inner diameter surface of the rotor 23b and integrally rotates, and one end in the axial direction (right side in FIG. 1) in the motor portion A is axially moved to the rolling bearing 36a. The other end (left side in FIG. 1) is rotatably supported by a rolling bearing 36b.

The reduction gear input shaft 25 has a substantially central portion on the one side in the axial direction (right side in FIG. 1) at the rolling bearing 37a and an end portion on the other side in the axial direction (left side in FIG. 1) at the rolling bearing 37b. Is supported so as to be freely rotatable. The speed reducer input shaft 25 has

eccentric portions

25 a and 25 b in the speed reduction portion B. The two

eccentric portions

25a and 25b are provided with a 180 ° phase change in order to cancel the centrifugal force due to the eccentric motion.

The motor rotating shaft 24 and the speed reducer input shaft 25 are coupled by spline fitting (including serrations, the same applies hereinafter), and the driving force of the motor part A is transmitted to the speed reducing part B. The spline fitting portion is configured to suppress the influence on the motor rotating shaft 24 even if the speed reducer input shaft 25 is inclined to some extent. In the present specification and claims, the torque transmission portion means a spline (including serration) fitting portion.

The deceleration part B includes curved plates 26a and 26b as revolving members that are rotatably held by the

eccentric parts

25a and 25b, and a plurality of outer pins as outer peripheral engaging members that engage with the outer peripheral parts of the curved plates 26a and 26b. 27, a motion conversion mechanism for transmitting the rotational motion of the curved plates 26a, 26b to the reducer output shaft 28, and a counterweight 29 at a position adjacent to the

eccentric portions

25a, 25b.

The reduction gear output shaft 28 has a flange portion 28a and a shaft portion 28b. In the flange portion 28a, holes for fixing the inner pins 31 at equal intervals are formed on a circumference centered on the rotation axis of the reduction gear output shaft 28. The shaft portion 28b is connected to a hub wheel 32 as an inner member of the wheel bearing portion C by spline fitting, and transmits the output of the speed reduction portion B to the wheel 14 (see FIG. 10). The reduction gear output shaft 28 is rotatably supported on the outer pin housing 60 by a rolling bearing 46.

As shown in FIG. 2, the curved plate 26 a has a plurality of corrugations formed of a trochoidal curve such as epitrochoid on the outer peripheral portion, and a plurality of through holes 30 a penetrating from one end face to the other end face, It has a through hole 30b. A plurality of through holes 30a are provided at equal intervals on the circumference centered on the rotation axis of the curved plate 26a, and receive inner pins 31 described later. Further, the through hole 30b is provided at the center of the curved plate 26a and is fitted to the eccentric portion 25a.

The curved plate 26a is rotatably supported by the rolling bearing 41 with respect to the eccentric portion 25a. As shown in FIG. 2, the rolling bearing 41 is directly fitted to the inner ring 42 having an inner raceway surface 42a on the outer diameter surface and the inner diameter surface of the through hole 30b of the curved plate 26a. A cylindrical roller bearing comprising an outer raceway surface 43 formed, a plurality of cylindrical rollers 44 disposed between the inner raceway surface 42a and the outer raceway surface 43, and a cage (not shown) for holding the cylindrical rollers 44. is there. Moreover, the inner ring | wheel 42 has a collar part which protrudes to a radial direction outer side from the axial direction both ends of the inner side track surface 42a.

As shown in FIG. 2, the outer pins 27 are provided at equal intervals on the circumference centering on the rotational axis of the speed reducer input shaft 25. When the curved plates 26a and 26b revolve, the curved waveform and the outer pin 27 engage with each other to cause the curved plates 26a and 26b to rotate. The outer pin 27 is rotatably supported by the outer pin housing 60 (see FIG. 1) by a needle roller bearing 27a. Thereby, the contact resistance between the curved plates 26a and 26b can be reduced.

The counterweight 29 (see FIG. 1) is substantially fan-shaped and has a through-hole that fits with the speed reducer input shaft 25, and each counterweight 29 (see FIG. 1) has a through hole that is caused by the rotation of the curved plates 26a and 26b. It is arranged at a position adjacent to the

eccentric parts

25a, 25b with a phase difference of 180 ° from that of the

eccentric parts

25a, 25b.

As shown in FIG. 1, the motion conversion mechanism is composed of a plurality of inner pins 31 held by the reduction gear output shaft 28 and through holes 30a provided in the curved plates 26a and 26b. The inner pins 31 are provided at equal intervals on the circumference centering on the rotational axis of the speed reducer output shaft 28 (see FIG. 2), and one axial end thereof is fixed to the speed reducer output shaft 28. Has been. Further, in order to reduce the frictional resistance with the curved plates 26a, 26b, a needle roller bearing 31a is provided at a position where the curved plates 26a, 26b come into contact with the inner wall surface of the through hole 30a.

As shown in FIG. 1, a stabilizer 31 b is provided at the other axial end of the inner pin 31. The stabilizer 31b includes an annular ring portion 31c and a cylindrical portion 31d extending in the axial direction from the inner diameter surface of the annular portion 31c. The ends on the other axial side of the plurality of inner pins 31 are fixed to the annular portion 31c. Since the load applied to some of the inner pins 31 from the curved plates 26a and 26b is supported by all the inner pins 31 via the stabilizer 31b, the stress acting on the inner pins 31 is reduced and the durability is improved. be able to.

As shown in FIG. 2, the through hole 30 a is provided at a position corresponding to each of the plurality of inner pins 31, and the inner diameter dimension of the through hole 30 a is the outer diameter dimension of the inner pin 31 (“the needle roller bearing 31 a. The maximum outer diameter is included. ”The same shall apply hereinafter.

The state of the load acting on the curved plates 26a and 26b will be described with reference to FIG. Axis O ₂ of the eccentric portion 25a is eccentric by the eccentricity e from the axis O of the reduction gear input shaft 25. The outer periphery of the eccentric portion 25a is attached is curved plates 26a, the eccentric part 25a is so rotatably supports the curve plate 26a, the axial center _{O 2} is also the axis of the curved plate 26a. The outer periphery of the curved plate 26a is formed by a corrugated curve, and has corrugated recesses 34 that are depressed in the radial direction at equal intervals in the circumferential direction. Around the curved plate 26a, a plurality of outer pins 27 that engage with the recesses 34 are arranged in the circumferential direction with the axis O as the center.

In FIG. 3, when the eccentric portion 25a rotates counterclockwise along with the speed reducer input shaft 25, the eccentric portion 25a revolves around the axis O, so that the concave portion 34 of the curved plate 26a The pin 27 is sequentially brought into contact with the circumferential direction. As a result, as indicated by the arrow, the curved plate 26a receives the load Fi from the plurality of outer pins 27 and rotates clockwise.

Further, the curved plates 26a through hole 30a has a plurality circumferentially disposed about the axis O _2. An inner pin 31 that is coupled to the reduction gear output shaft 28 that is disposed coaxially with the axis O is inserted through each through hole 30a. Since the inner diameter of the through-hole 30a is larger than the outer diameter of the inner pin 31, the inner pin 31 does not hinder the revolving motion of the curved plate 26a, and the inner pin 31 extracts the rotational motion of the curved plate 26a. The reduction gear output shaft 28 (see FIG. 1) is rotated. At this time, the speed reducer output shaft 28 has a higher torque and a lower rotational speed than the speed reducer input shaft 25, and the curved plate 26a receives the load Fj from the plurality of inner pins 31 as indicated by arrows in FIG. . A resultant force Fs of the plurality of loads Fi and Fj is applied to the reduction gear input shaft 25.

The direction of the resultant force Fs changes depending on geometrical conditions such as the waveform shape of the curved plate 26a, the number of the concave portions 34, and centrifugal force. Specifically, the angle α between the reference line X perpendicular to the straight line Y connecting the rotation axis O ₂ and the axis O and passing through the axis O ₂ and the resultant force Fs is approximately 30 ° to 60 °. fluctuate.

The load directions and magnitudes of the plurality of loads Fi and Fj change during one rotation (360 °) of the speed reducer input shaft 25. As a result, the resultant force Fs acting on the speed reducer input shaft 25 is also reduced. Direction and size vary. Then, when the speed reducer input shaft 25 makes one rotation, the corrugated concave portion 34 of the curved plate 26a is decelerated and rotated clockwise by one pitch, resulting in the state shown in FIG.

As shown in FIG. 1, the wheel bearing 33 of the wheel bearing portion C includes an inner raceway surface 33f formed directly on the outer diameter surface of the hub wheel 32 and an inner ring 33a fitted to a small diameter step portion of the outer diameter surface. And an outer ring 33b fitted and fixed to the inner surface of the casing 22, and a plurality of balls 33c as rolling elements disposed between the inner raceway surface 33f, the inner ring 33a and the outer ring 33b, and adjacent to each other. This is a double-row angular contact ball bearing provided with a retainer 33d for holding the gap between the balls 33c to be sealed and a seal member 33e for sealing both axial ends of the wheel bearing 33.

Next, the lubrication mechanism will be described. This lubricating mechanism supplies lubricating oil for cooling the motor part A and supplies lubricating oil to the speed reducing part B. Although the details will be described later, this lubricating mechanism has the characteristic configuration of the present embodiment. Involved. Lubricating

oil passages

24a, 25c, lubricating

oil supply ports

24b, 24c, 25d, 25e, 25f, a lubricating oil discharge port 22b, a lubricating oil reservoir 22d, a lubricating oil passage 22e, a rotary pump 51, and a circulating oil passage 45 shown in FIG. Is the main configuration. The white arrow given in the lubrication mechanism indicates the direction in which the lubricating oil flows.

The lubricating oil passage 25c connected to the lubricating oil passage 24a of the motor rotating shaft 24 extends along the axial direction inside the reduction gear input shaft 25. The lubricating

oil supply ports

25d and 25e extend radially from the lubricating oil passage 25c toward the outer diameter surface of the reduction gear input shaft 25, and the lubricating oil supply port 25f extends from the shaft end of the reduction gear input shaft 25 to the rotating shaft. It extends toward the axial end surface in the center direction.

At least one location of the casing 22 at the position of the speed reduction part B is provided with a lubricating oil discharge port 22b for discharging the lubricating oil inside the speed reduction part B, and a lubricating oil storage part 22d for temporarily storing the discharged lubricating oil. Is provided.

As shown in FIG. 1, the circulating oil passage 45 is connected to an axial oil passage 45 a extending in the axial direction inside the casing 22 and one axial end portion (right side in FIG. 1) of the axial oil passage 45 a. A radial oil passage 45c extending in the direction and a radial oil passage 45b extending in the radial direction connected to the other axial end portion (left side in FIG. 1) of the axial oil passage 45a.

In order to forcibly circulate the lubricating oil, a rotary pump 51 is provided between the lubricating oil passage 22e connected to the lubricating oil reservoir 22d and the circulating oil passage 45. The radial oil passage 45b supplies the lubricating oil pumped from the rotary pump 51 to the axial oil passage 45a, and supplies the lubricating oil from the axial oil passage 45a to the lubricating

oil passages

24a and 25c via the radial oil passage 45c. .

As shown in FIG. 4, the rotary pump 51 includes an inner rotor 52 that rotates using the rotation of the reduction gear output shaft 28, an outer rotor 53 that rotates following the rotation of the inner rotor 52, and a pump chamber 54. The cycloid pump includes a suction port 55 communicating with the lubricating oil passage 22e and a discharge port 56 communicating with the radial oil passage 45b of the circulating oil passage 45. By disposing the rotary pump 51 in the casing 22, it is possible to prevent the in-wheel motor drive device 21 as a whole from being enlarged.

The inner rotor 52 rotates around a rotation center c _1, whereas, the outer rotor 53 rotates around a rotation center c _2. Since the inner rotor 52 and the outer rotor 53 rotate about different rotation centers c ₁ and c ₂ , the volume of the pump chamber 54 changes continuously. As a result, the lubricating oil flowing in from the suction port 55 is pumped from the discharge port 56 to the radial oil passage 45b.

As shown in FIG. 1, a part of the lubricating oil recirculated from the circulating oil passage 45 to the lubricating oil passage 24a cools the rotor 23b from the lubricating

oil supply ports

24c and 24b by centrifugal force. Thereafter, the lubricating oil is scattered to cool the stator 23a. Lubricating oil divides into this path and a path for lubricating and cooling the speed reducing portion B described later.

As the lubrication of the speed reducing part B, the lubricating oil in the lubricating oil path 25c flows out from the lubricating

oil supply ports

25d and 25e to the speed reducing part B due to the centrifugal force and pressure accompanying the rotation of the speed reducer input shaft 25. The lubricating oil that has flowed out of the lubricating oil supply port 25d is a cylindrical roller bearing 41 (see FIG. 2) that supports the curved plates 26a and 26b, and further, a contact portion between the curved plates 26a and 26b and the inner pin 31 by centrifugal force. Further, it moves radially outward while lubricating the contact portion between the curved plates 26a, 26b and the outer pin 27, and the like. The lubricating oil that has flowed out of the lubricating

oil supply ports

25e and 25f is supplied to deep

groove ball bearings

37a and 37b that support the reduction gear input shaft 25, as well as internal bearings and contact portions. Thus, the deceleration part B is comprised from many bearings and contact parts which need lubrication, and needs to supply lubricating oil efficiently by the built-in rotary pump 51. FIG.

The lubricating oil that has reached the inner wall surface of the casing 22 is discharged from the lubricating oil discharge port 22b and stored in the lubricating oil reservoir 22d. Since the lubricating oil reservoir 22d is provided between the lubricating oil discharge port 22b and the rotary pump 51, even if lubricating oil that cannot be discharged by the rotary pump 51 is temporarily generated, the lubricating oil reservoir 22d Can be stored. As a result, an increase in torque loss of the deceleration unit B can be prevented. On the other hand, even if the amount of the lubricating oil reaching the lubricating oil discharge port 22b decreases, the rotary pump 51 can return the lubricating oil stored in the lubricating oil storage portion 22d to the lubricating

oil paths

24a and 25c. Lubricating oil moves by gravity in addition to centrifugal force. Therefore, it is desirable to attach to the electric vehicle 11 so that the lubricating oil reservoir 22d is positioned below the in-wheel motor drive device 21.

The overall configuration of the in-wheel motor drive device 21 according to the present embodiment is as described above. Next, a characteristic configuration of the in-wheel motor drive device 21 of the present embodiment will be described. In summary, the lubricating

oil passages

24 a and 25 c constituting a part of the above-described lubrication mechanism are formed in the motor rotation shaft 24 and the reducer input shaft 25, respectively. A hollow pipe member 80 forming the lubricating oil passage 24a is fitted. The lubricating oil path 24a of the hollow pipe member 80 and the lubricating oil path 25c of the reduction gear input shaft 25 cooperate to lubricate and cool the path for cooling the rotor 23b of the motor part A and spraying it to the stator 23a, and the speed reducing part B. It is possible to efficiently divert to the route.

FIG. 5 is an enlarged longitudinal sectional view of the peripheral portion of the torque transmission portion of the reduction gear input shaft 25 and the motor rotation shaft 24 of FIG. 1, and FIG. 6a is an enlargement of the motor rotation shaft 24 in which the hollow pipe member 80 is fitted. FIG. 6b is an enlarged view of a portion D in FIG. 6a. FIG. 7 shows a single hollow pipe member 80.

As shown in FIG. 6a, the motor rotating shaft 24 has a large-diameter outer diameter portion 61 formed at a substantially central portion in the axial direction, and the rotor 23b is fitted and fixed to the large-diameter outer diameter portion 61. A mounting surface 65 of the rolling bearing 36a (see FIG. 1) is formed on the outer diameter of one end of the motor rotating shaft 24, and a mounting surface 66 of the rolling bearing 36b (see FIG. 1) is formed on the outer diameter of the other end. Yes.

A female spline 67 is formed on the inner diameter of the other end of the motor rotating shaft 24 (left side in FIG. 6A). In order to broach the female spline 67, it is necessary to form a through hole 68 having a diameter slightly larger than the large diameter of the female spline 67. For this reason, the through hole 68 is greatly different from the inner diameter F of the lubricating oil passage 25c of the reduction gear input shaft 25 shown in FIG. In the case of the prior art in which the through hole 68 is used as a lubricating oil passage, a step is formed at the connection portion between the reduction gear input shaft 25 and the inner diameter F of the lubricating oil passage 25c, and as a result, the lubricating oil flowing into the motor rotating shaft 24 is generated. Is blocked in the previous stage that flows into the lubricating oil passage 25c of the reduction gear input shaft 25. Therefore, the above-described overall lubrication mechanism has a problem that it is difficult to supply lubricating oil to the speed reduction unit B side in the low rotation range. The present embodiment solves this problem.

As shown in FIG. 6 a, a lubricating oil supply port 24 b communicating from the through hole 68 to the large diameter outer diameter portion 61 is formed in the motor rotating shaft 24 in the radial direction, and the hollow pipe member 80 is fitted into the through hole 68. Has been. The hollow pipe member 80 is formed with a lubricating oil passage 24a penetrating the shaft center, and a plurality of lubricating oil supply ports 24c are arranged in the radial direction corresponding to the lubricating oil supply port 24b of the motor rotating shaft 24 (this embodiment). 4 in the form) are provided. A circumferential groove 24d is provided on the outer peripheral portion of the lubricating oil supply port 24c.

7, the hollow pipe member 80 has a fitting portion 80b formed at one end (right side in FIG. 7) and a small-diameter stepped portion 80a formed at the other end (left side in FIG. 7). The outer diameter portion 80d between the small diameter step portion 80a and the fitting portion 80b at both ends is formed to have a smaller diameter than the inner diameter of the through hole 68 of the motor rotating shaft 24. The lubricating oil passage 24 a formed in the axial center of the hollow pipe member 80 has an inner diameter E. A phase matching projection 80c is formed at the end of the fitting portion 80b.

Next, the procedure for mounting the hollow pipe member 80 on the motor rotating shaft 24 will be described with reference to FIG. 6a. First, the hollow pipe member 80 is inserted into the through hole 68 of the motor rotating shaft 24, and the small diameter step portion 80a provided at the end is fitted into the small diameter portion of the female spline 67 of the motor rotating shaft 24 by a clearance fit. Take it out. In this state, the fitting portion 80 b of the hollow pipe member 80 is press-fitted into the through hole 68 of the motor rotating shaft 24. At this time, as shown in FIG. 6b, the protrusion 80c formed at the end of the fitting portion 80b engages with the groove 68a formed at the end of the through hole 68 of the motor rotating shaft 24, and the phase is adjusted. It is done. In the present specification and claims, the phase alignment engaging portion means the protrusion 80c and the groove 68a, and in the modification described later, it means the protrusion 80c 'and the groove 68a.

Since the outer diameter portion 80d between the small diameter step portion 80a and the fitting portion 80b at both ends of the hollow pipe member 80 is formed to be smaller in diameter than the inner diameter of the through hole 68 of the motor rotating shaft 24, the hollow pipe member 80 is When fitted to the motor rotating shaft 24, the hollow pipe member 80 can be inserted without being pressed in the entire axial length, and only the fitting portion 80 b is press-fitted into the through hole 68. For this reason, assembly work can be facilitated.

In addition, the fitting portion 80b of the hollow pipe member 80 is press-fitted into the through hole 68 of the motor rotating shaft 24 in a centered state by fitting the small-diameter step portion 80a to the small-diameter portion of the female spline 67, thereby improving the rotation accuracy. Can be made.

Further, since the projections 80c of the hollow pipe member 80 are engaged with the grooves 68a of the motor rotating shaft 24, the phases of the lubricating oil supply port 24c of the hollow pipe member 80 and the lubricating oil supply port 24b of the motor rotating shaft 24 are adjusted. Can be matched. However, in this embodiment, since the circumferential groove 24d is formed in the outer peripheral portion of the lubricating oil supply port 24c of the hollow pipe member 80, the phase alignment is not particularly necessary. Therefore, either the phase matching structure of the protrusion 80c and the groove 68a or the circumferential groove 24d may be omitted.

Although not shown in the drawings, the hollow pipe member can be obtained by sufficiently increasing the diameter of one of the lubricating oil supply port 24c of the hollow pipe member 80 and the lubricating oil supply port 24b of the motor rotating shaft 24 from the other hole diameter. Even when the lubricating oil supply port 24c of 80 and the lubricating oil supply port 24b of the motor rotating shaft 24 are out of phase, a communication structure that does not hinder the supply of the lubricating oil can be achieved.
In this case, the phase alignment structure of the protrusion 80c and the groove 68a and the circumferential groove 24d can be omitted.

An iron-based metal was used as a material for the hollow pipe member 80. Although a resin material can be used as the material of the hollow pipe member 80, it is difficult to secure a tightening allowance in the entire region of the usage environment due to the influence of the thermal expansion coefficient. A fixing method using an O-ring is also conceivable, but a fixing method that induces imbalance in the motor rotating shaft 24 that rotates at a high speed of about 15000 min ⁻¹ is not preferable, and the anti-rotation effect is also uncertain.

As described above, since the hollow pipe member 80 in which the lubricating oil passage 24a is formed is fitted to the motor rotating shaft 24, the lubrication formed on the shaft center of the hollow pipe member 80 as shown in FIG. The inner diameter E of the oil passage 24 a is set to be approximately the same size as the inner diameter F of the lubricating oil passage 25 c formed in the shaft center of the speed reducer input shaft 25. As a result, there is no step between the lubricating oil path 24a of the motor rotating shaft 24 and the lubricating oil path 25c of the reduction gear input shaft 25, and the reduction gear input shaft 25 can be moved from the lubricating oil path 24a of the motor rotating shaft 24 even in a low rotation range. Lubricating oil can be effectively flowed into the lubricating oil passage 25c.

Next, a modification of the hollow pipe member is shown in FIG. The hollow pipe member 80 'is obtained by reducing the diameter of a steel pipe by swaging. The hollow pipe member 80 ′ has one end (left side in FIG. 8) having a small diameter portion 80a ′ that fits into the small diameter portion of the female spline 67 of the motor rotating shaft 24 in the same manner as the hollow pipe member 80 of the above-described embodiment. A fitting portion 80b ′ that is press-fitted into the through hole 68 of the motor rotating shaft 24 is formed at the other end (right side in FIG. 8). The diameter is reduced from the large-diameter fitting portion 80b 'to a taper shape and connected to the small-diameter portion 80a'. The small diameter portion 80a 'is formed over most of the axial direction.

The hollow pipe member 80 ′ is formed with a lubricating oil passage 24a ′ penetrating the shaft center, and a plurality of lubricating oil supply ports 24c ′ are arranged in the radial direction at axial positions corresponding to the lubricating oil supply ports 24b of the motor rotating shaft 24. (Four in this modification) are provided. A phase matching projection 80c 'is provided at the end of the fitting portion 80b' of the hollow pipe member 80 '. Unlike the above-described embodiment, no circumferential groove is provided in the outer peripheral portion of the lubricating oil supply port 24 c ′, but the lubricating oil supply port 24 c ′ of the hollow pipe member 80 ′ is connected to the motor rotating shaft 24. Since the phase coincides with the lubricating oil supply port 24b, the lubricating oil is effectively supplied.

The inner diameter E of the lubricating oil passage 24 a ′ of the hollow pipe member 80 ′ of this modification is also set to be approximately the same size as the inner diameter F of the lubricating oil passage 25 c formed in the shaft center of the reduction gear input shaft 25. Therefore, it has the same effect as the above-described embodiment.

Since the hollow pipe member 80 ′ of the present modification is obtained by reducing the diameter of a steel pipe, there is little change in the wall thickness, and the weight can be reduced while suppressing the manufacturing cost. The diameter reduction processing may be performed by pressing in addition to the swaging processing. The contents of the above-described embodiment apply mutatis mutandis for other configurations and operational effects.

The overall operating principle of the in-wheel motor drive device 21 configured as described above will be described.

With reference to FIGS. 1 and 2, the motor unit A receives, for example, an electromagnetic force generated by supplying an alternating current to the coil of the stator 23 a, and the rotor 23 b made of a permanent magnet or a magnetic body rotates. . Thereby, when the reduction gear input shaft 25 connected to the motor rotation shaft 24 rotates, the curved plates 26 a and 26 b revolve around the rotation axis of the reduction gear input shaft 25. At this time, the outer pin 27 engages with the curved waveform of the curved plates 26 a and 26 b to rotate the curved plates 26 a and 26 b in the direction opposite to the rotation of the speed reducer input shaft 25.

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

At this time, since the rotation of the speed reducer input shaft 25 is decelerated by the speed reducer B and is transmitted to the speed reducer output shaft 28, it is necessary for the drive wheel 14 even when the low torque, high speed motor part A is adopted. It is possible to transmit an appropriate torque.

The reduction ratio of the speed reduction unit B having the above-described configuration is calculated as (Z _A −Z _B ) / Z _B where Z _{A is} the number of outer pins 27 and Z _B is the number of waveforms of the curved plates 26a and 26b. In the embodiment shown in FIG. 2, since Z _A = 12 and Z _B = 11, a very large reduction ratio of 1/11 can be obtained.

In this way, by adopting the reduction part B that can obtain a large reduction ratio without using a multistage configuration, the in-wheel motor drive device 21 having a compact and high reduction ratio can be obtained. Further, by providing the

needle roller bearings

27a and 31a on the outer pin 27 and the inner pin 31, the frictional resistance between the curved plates 26a and 26b is reduced, so that the transmission efficiency of the speed reduction portion B is improved.

By mounting the in-wheel motor drive device 21 according to this embodiment on the electric vehicle 11, the unsprung weight can be suppressed. As a result, the electric vehicle 11 having excellent running stability and NVH characteristics can be obtained.

In the present embodiment and the modified example, the lubricating oil supply port 24b is provided at a substantially central portion in the axial direction of the motor rotating shaft 24, the lubricating oil supply port 25e is provided near the rolling bearing 37a, and the lubricating oil supply port 25d is provided as an eccentric portion. Although the example which provided in 25a, 25b and provided the lubricating oil supply port 25f in the shaft end of the reduction gear input shaft 25 was shown, it does not restrict to this but arbitrary positions of the motor rotating shaft 24 or the reduction gear input shaft 25 are shown. Can be provided.

Although an example of a cycloid pump has been shown as the rotary pump 51, the present invention is not limited to this, and any rotary pump that is driven using the rotation of the speed reducer output shaft 28 can be adopted. Furthermore, the rotary pump 51 may be omitted, and the lubricating oil may be circulated only by centrifugal force.

Although the example in which two curved plates 26a and 26b of the deceleration unit B are provided with the phase shifted by 180 ° is shown, the number of the curved plates can be arbitrarily set. For example, when three curved plates are provided, , 120 ° phase may be changed.

Although the motion conversion mechanism has shown the example comprised by the inner pin 31 fixed to the reduction gear output shaft 28, and the through-hole 30a provided in the curve board 26a, 26b, it is not restricted to this, The reduction part It is possible to adopt an arbitrary configuration that can transmit the rotation of B to the hub wheel 32. For example, it may be a motion conversion mechanism composed of an inner pin fixed to a curved plate and a hole formed in a reduction gear output shaft.

The description of the operation in the present embodiment has been made by paying attention to the rotation of each member, but in reality, power including torque is transmitted from the motor unit A to the drive wheels 14. Therefore, the power decelerated as described above is converted into high torque.

Also, the case where power is supplied to the motor unit A to drive the motor unit and the power from the motor unit A is transmitted to the drive wheels 14 is shown, but conversely, the vehicle decelerates or goes down the hill. In such a case, the power from the drive wheel 14 side may be converted into high-rotation low-torque rotation by the speed reduction unit B and transmitted to the motor unit A, and the motor unit A may generate power. 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 present embodiment, an example in which a radial gap motor is adopted as the motor unit A has been shown, but the present invention is not limited to this, and a motor having an arbitrary configuration can be applied. For example, it may be an axial gap motor including a stator fixed to the casing and a rotor disposed at a position facing the stator with an axial gap inside the stator.

In the present embodiment and the modification, the example in which the cycloid reducer is applied to the reduction unit is illustrated, but the present invention is not limited to this, and other types of reduction devices such as a planetary gear reducer may be applied.

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

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

11 Electric car, 12 Chassis, 12a Wheel housing, 12b Suspension device, 13 Front wheel, 14 Rear wheel, 21 In-wheel motor drive device, 22 Casing, 22a Bearing mounting surface, 22b Lubricating oil discharge port, 22d Lubricating oil reservoir, 22e Lubricating oil passage, 23a stator, 23b rotor, 24 motor rotation shaft, 24b lubricating oil passage, 24c lubricating oil supply port, 24d groove, 25 speed reducer input shaft, 25a eccentric portion, 25b eccentric portion, 25c lubricating oil passage, 25d lubrication Oil supply port, 25e Lubricating oil supply port, 26a curved plate, 26b curved plate, 27 outer pin, 27a needle roller bearing, 28 reducer output shaft, 29 counterweight, 30b through hole, 31 inner pin, 3 a Needle roller bearing, 31b stabilizer, 31c annular part, 31d cylindrical part, 32 hub wheel, 33 wheel bearing, 33a inner ring, 33b outer ring, 33c ball, 33d retainer, 33e seal member, 33f inner raceway surface, 36a Rolling bearing, 36b Rolling bearing, 37a Rolling bearing, 37b Rolling bearing, 41 Rolling bearing, 42 Inner ring, 43 Outer raceway surface, 44 Cylindrical roller, 45 Circulating oil path, 45a Axial oil path, 45b Radial oil path, 45c Diameter Directional oil passage, 46, rolling bearing, 51, rotary pump, 52, inner rotor, 53, outer rotor, 54, pump chamber, 55, inlet, 56, outlet, 60, outer pin housing, 61, large diameter outer diameter, 62 collar, 2a outer surface, 63 clamping member, 65 bearing mounting surface, 66 bearing mounting surface, 67 female spline, 68 through hole, 68a groove, 80, 80 'hollow pipe member, 80b, 80b' fitting part, 80c, 80c 'projection , E inner diameter, F inner diameter

Claims

A motor comprising a motor part, a speed reduction part, a wheel bearing part, and a casing, wherein the motor part is rotatably supported by the casing via a stator fixed to the casing and a plurality of rolling bearings. It consists of a rotating shaft and a rotor mounted on the motor rotating shaft, and the motor rotating shaft of the motor unit rotates the speed reducer input shaft of the speed reducing unit, decelerates the speed of the speed reducer input shaft and decelerates. An in-wheel motor drive device that is transmitted to a machine output shaft, the wheel bearing portion is connected to the speed reducer output shaft, and includes a lubrication mechanism therein;
The outer periphery of the torque transmission part of the speed reducer input shaft is fitted to the inner periphery of the torque transmission part of the motor rotation shaft, and a lubricating oil path constituting a part of the lubrication mechanism is formed between the motor rotation shaft and the speed reduction part. An in-wheel motor drive device, characterized in that a hollow pipe member that is formed inside each machine input shaft and that forms the lubricating oil passage is fitted to the motor rotation shaft.
The in-wheel motor drive device according to claim 1, wherein the inner diameter of the hollow pipe member and the inner diameter of the lubricating oil passage of the speed reducer input shaft are set to be substantially the same size.
The lubricating oil supply port is formed in the hollow pipe member in the radial direction, and the lubricating oil supply port is also formed in the radial direction in the motor rotating shaft. In-wheel motor drive device.
The in-wheel motor drive device according to any one of claims 1 to 3, wherein a circumferential groove is formed in an outer peripheral portion of the lubricating oil supply port of the hollow pipe member.
4. The in-wheel motor drive device according to claim 3, wherein one of the lubricating oil supply port of the hollow pipe member and the lubricating oil supply port of the motor rotating shaft is made larger than the other.
The in-wheel motor drive device according to claim 3 or 5, wherein phases of the lubricating oil supply port of the hollow pipe member and the lubricating oil supply port of the motor rotating shaft are matched.
In order to match the phases of the lubricating oil supply port of the hollow pipe member and the lubricating oil supply port of the motor rotating shaft, a phase matching engagement portion is provided between the hollow pipe member and the motor rotating shaft. The in-wheel motor drive apparatus as described in any one of Claim 3, 5, 6 characterized by these.
The in-wheel motor drive device according to any one of claims 1 to 7, wherein the hollow pipe member and the motor rotation shaft have a fitting structure having a tightening margin at a shaft end.