WO2012111411A1

WO2012111411A1 - Device for driving in-wheel motor

Info

Publication number: WO2012111411A1
Application number: PCT/JP2012/051914
Authority: WO
Inventors: 眞也大岡; 山本　哲也
Original assignee: Ntn株式会社
Priority date: 2011-02-18
Filing date: 2012-01-30
Publication date: 2012-08-23
Also published as: JP2012171420A

Abstract

Provided is a device for driving an in-wheel motor, which is not broken by flying stones or the like and has easy-to-process flow passes for cooling purposes and for an inner lubricant oils. A device for driving an in-wheel motor, which comprises a motor part (A) which can generate a driving force for a wheel and is arranged in the wheel, wherein a pipe (61, 62) which constitutes a flow pass as a passage for cooling water for cooling the inside or as an oil passage for a lubricant oil is formed in a housing (22) in the motor part (A) by insert molding, the housing (22) is composed of a cast product of a light metal such as an aluminum alloy and a magnesium alloy, and the pipe (61, 62) can be formed by casting a pipe material that can be formed into the pipe during the casting.

Description

In-wheel motor drive device

The present invention relates to an in-wheel motor drive device, and more particularly to cooling of the device and a flow path of internal lubricating oil.

A conventional in-wheel motor drive device 101 is described in, for example, Japanese Patent Application Laid-Open No. 2009-174593 (Patent Document 1).

An in-wheel motor drive device 101 shown in FIG. 6 includes a motor unit 103 that rotationally drives the motor-side rotating member 106, a speed reducing unit 105 that decelerates the rotation of the motor-side rotating member 106 and transmits the rotation to the wheel-side rotating member 108. And a wheel hub bearing portion 104 having a wheel hub 109 fixedly connected to the wheel side rotating member 108.

JP 2009-174593 A

By the way, the in-wheel motor drive device 101 normally requires a cooling water passage 107 for internal cooling and an oil passage 110 for lubricating oil.

Conventionally, the cooling water passage 107 for internal cooling and the oil passage 110 for lubricating oil are formed by post-processing the housing 102 of the motor unit 103. Processing is difficult when man-hours are required and the cooling water passage 107 and the oil passage 110 are thin.

In addition, when a flow path is formed on the outer peripheral surface of the outside of the housing 102 of the motor unit 103, the pipe forming the flow path may be damaged by a stepping stone, contact, etc., and the liquid may flow out.

Therefore, the present invention is intended to provide a cooling and internal lubricating oil flow path structure that is easy to process without worrying about breakage due to stepping stones and the like.

In order to solve the above-described problems, the present invention provides an in-wheel motor drive device having a motor unit for generating a wheel driving force in the wheel, the flow of a cooling water channel for internal cooling or an oil channel for lubricating oil. A pipe constituting the path is formed by insert molding in the housing of the motor unit.

The housing is made of a cast product of a light metal such as an aluminum alloy or a magnesium alloy, and the pipe can be formed by casting a pipe material that becomes a pipe at the time of casting.

The pipe can be used as a cooling pipe through which a cooling liquid for the motor section flows.

¡The cooling pipe can communicate with the outside of the motor unit.

It is preferable to arrange the cooling pipe in one or a spiral shape in the circumferential direction of the housing of the motor unit.

The piping can also be used as a lubricating piping through which lubricating oil flows.

The lubrication pipe can also be used for cooling the motor unit.

The lubrication pipe is provided so as to circulate inside the apparatus without communicating with the outside of the apparatus.

¡The lubrication pipes are arranged in the radial direction and the axle direction.

Only one of the cooling pipe and the lubricating pipe may be provided, but it is preferable to provide both.

It is preferable that a built-in pump for circulating the lubricating oil in the lubrication pipe is installed in the apparatus.

The number of rotations of the built-in pump is set to be the same as the number of rotations of the motor unit when the reduction unit of the motor unit is not provided, and different from the number of rotations of the motor unit when the reduction number of the motor unit is provided. The

In the present invention, as described above, the pipes constituting the flow path of the cooling water passage for internal cooling or the oil passage for lubricating oil are formed in the housing of the motor portion by insert molding, so that breakage of stepping stones, etc. It is possible to easily form a thin channel.

It is a schematic sectional drawing of the in-wheel motor drive device concerning one Embodiment of this invention. 1 is an overall view of a cooling pipe that is insert-molded in an in-wheel motor drive device according to an embodiment of the present invention. It is a schematic plan view of the electric vehicle which has an in-wheel motor drive device. It is the figure seen from the electric vehicle back of FIG. It is a schematic longitudinal cross-sectional view of the deceleration part of embodiment of FIG. It is a schematic sectional drawing of the conventional in-wheel motor drive device.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 3, an electric vehicle 11 having an in-wheel motor drive device according to an embodiment of the present invention includes a chassis 12, a front wheel 13 as a steering wheel, a rear wheel 14 as a drive wheel, And an in-wheel motor drive device 21 that transmits a driving force to each of the rear wheels 14. As shown in FIG. 4, the rear wheel 14 is housed inside a wheel housing 12 a of the chassis 12, and is fixed to the lower portion of the chassis 12 via a suspension device (suspension) 12 b.

The suspension device 12b 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. Furthermore, a stabilizer that suppresses the inclination of the vehicle body when turning is provided at the connecting portion of the left and right suspension arms. The suspension device 12b is an independent suspension type in which the left and right wheels can be moved up and down independently in order to improve the followability to the road surface unevenness and efficiently transmit the driving force of the driving wheels to the road surface. Is desirable.

The electric vehicle 11 needs to be provided with a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 12 by providing an in-wheel motor drive device 21 for driving the left and right rear wheels 14 inside the wheel housing 12a. This eliminates the need to secure a wide cabin space and control the rotation of the left and right drive wheels.

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

As shown in FIG. 1, the in-wheel motor drive device 21 includes a motor unit A that generates a driving force, a deceleration unit B that decelerates and outputs the rotation of the motor unit A, and an output from the deceleration unit B as driving wheels. 14 and a wheel hub bearing portion C for transmission to the motor vehicle 14 and is mounted in the wheel housing 12a of the electric vehicle 11 as shown in FIG.

The housing 22 of the motor part A is a cast product of a light metal such as an aluminum alloy or a magnesium alloy. In casting, a pipe material is cast by insert molding, and a cooling water channel for internal cooling or an oil channel for lubricating oil is used. A pipe constituting the flow path is formed.

The pipe includes a cooling pipe 61 through which a cooling liquid for the motor part A flows and a lubricating pipe 62 through which lubricating oil flows.

The cooling pipe 61 is drawn out from the housing 22 so as to communicate with the outside of the motor part A.

The cooling pipe 61 is arranged in the circumferential direction of the housing 22 of the motor part A, and is preferably arranged in a spiral shape as shown in FIG.

The lubrication pipe 62 can also be used for cooling the motor part A.

The lubrication pipe 62 is provided so as to circulate inside the apparatus without communicating with the outside of the apparatus.

The lubrication pipe 62 is arranged in the radial direction and the axle direction.

The lubricating oil in the lubricating pipe 62 is circulated by the built-in pump 51.

The number of rotations of the built-in pump 51 is set to be the same as the number of rotations of the motor unit A when the motor unit A does not include the speed reduction unit B, but the motor unit A includes the speed reduction unit as in the embodiment. Is set to be different from the rotational speed of the motor part A.

The motor unit A is fixedly coupled to the stator 23 fixed to the housing 22 of the motor unit A, the rotor 24 disposed at a position facing the inner side of the stator 23 with a radial gap therebetween, and the inner side of the rotor 24. And a motor-side rotating member 24b that rotates integrally with the rotor 24. The motor side rotation member 24b is rotatably supported by the

rolling bearings

36a and 36b with respect to the housing 22 of the motor portion A.

The motor side rotating member 24b is arranged from the motor part A to the speed reduction part B in order to transmit the driving force of the motor part A to the speed reduction part B. The motor-side rotating member 24b has a hollow structure, and the input shaft 25 of the speed reduction portion B is fitted and fixed. The input shaft 25 is provided with

eccentric portions

25a and 25b. 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 speed reduction part B is held at fixed positions on the

curved plates

26a and 26b as revolving members that are rotatably held by the

eccentric parts

25a and 25b and the speed reduction part housing 22b. A plurality of outer pins 27 as outer peripheral engagement members to be combined, a motion conversion mechanism for transmitting the rotational motion of the

curved plates

26a and 26b to the wheel side rotation member 28, and a counterweight 29 at a position adjacent to the

eccentric portions

25a and 25b. With. In addition, the speed reduction part B is provided with a speed reduction part lubrication mechanism that supplies lubricating oil to the speed reduction part B.

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

As shown in FIG. 5, the

curved plates

26a and 26b have a plurality of corrugated waves composed of trochoidal curves such as epitrochoids on the outer periphery, and a plurality of through holes 30a penetrating from one end face to the other end face. Have A plurality of through holes 30a are provided at equal intervals on the circumference centering on the rotation axis of the

curved plates

26a, 26b, and receive inner pins 31 described later. Further, the through hole 30b is provided at the center of the

curved plates

26a and 26b and is fitted to the

eccentric portions

25a and 25b.

The

curved plates

26a and 26b are supported by the rolling bearing 41 so as to be rotatable with respect to the

eccentric portions

25a and 25b. The rolling bearing 41 is directly formed on the inner ring member having an inner raceway surface on the outer diameter surface of the

eccentric portions

25a and 25b and the inner diameter surface of the through hole 30b of the

curved plates

26a and 26b. A cylindrical roller bearing comprising an outer raceway surface, a plurality of cylindrical rollers 44 disposed between the inner raceway surface and the outer raceway surface, and a retainer (not shown) that holds the spacing between adjacent cylindrical rollers 44. .

The outer pins 27 are provided at equal intervals on a circumferential track centering on the rotation axis of the 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. Here, the outer pin 27 is rotatably supported with respect to the speed reduction unit housing 22b by a needle roller bearing. Thereby, the contact resistance between the

curved plates

26a and 26b can be reduced.

The counterweight 29 has a disc shape and has a through-hole that fits with the motor-side rotation member 25 at a position off the center, in order to cancel out the unbalanced inertia couple caused by the rotation of the

curved plates

26a and 26b. It is arranged at a position adjacent to each

eccentric part

25a, 25b with a 180 ° phase change from the eccentric part.

The motion conversion mechanism includes a plurality of inner pins 31 held by the wheel-side rotating member 28 and through holes 30a provided in the

curved plates

26a and 26b. The inner pins 31 are provided at equal intervals on a circumferential track centering on the rotational axis of the wheel side rotation member 28, and one axial end thereof is fixed to the wheel side rotation member 28. Further, in order to reduce the frictional resistance with the

curved plates

26a and 26b, needle roller bearings are provided at positions where they contact the inner wall surfaces of the through holes 30a of the

curved plates

26a and 26b.

The through hole 30a is provided at a position corresponding to each of the plurality of inner pins 31, and the inner diameter dimension of the through hole 30a indicates the outer diameter dimension of the inner pin 31 ("maximum outer diameter including needle roller bearing"). It is set larger by a predetermined amount than the same).

The speed reduction unit lubrication mechanism supplies lubricating oil to the speed reduction unit B, and includes a lubricating oil passage 52, a lubricating oil supply port 53, a lubricating oil discharge port 54, a lubricating oil storage unit 55, and a built-in pump 51. With.

The lubricating oil passage 52 extends along the axial direction inside the input shaft 25. The lubricating oil supply port 53 is provided in the

eccentric portions

25a and 25b.

Further, at least one position of the speed reduction part housing 22b at the position of the speed reduction part B is provided with a lubricating oil discharge port 54 for discharging the lubricating oil inside the speed reduction part B. Further, a lubricating pipe 62 that connects the lubricating oil discharge port 54 and the lubricating oil passage 52 is provided inside the housing 22 of the motor part A. Then, the lubricating oil discharged from the lubricating oil discharge port 54 returns to the lubricating oil passage 52 via the lubricating pipe 62.

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

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

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

A double-row ball 34 is accommodated between the outer raceway surface and the inner raceway surface of the hub wheel 32 and the fixed ring 33 facing each other.

The fixing flange 33 a of the fixed wheel 33 and the speed reduction unit housing 22 b are fastened by a bolt 71. Further, the speed reduction unit housing 22 b and the housing 22 of the motor unit A are fastened by bolts 72.

Hereinafter, the operation principle of the in-wheel motor drive device 21 will be described.
The motor unit A receives, for example, an electromagnetic force generated by supplying an alternating current to the coil of the stator 23, and the rotor 24 composed of a permanent magnet or a magnetic material rotates. As a result, when the input shaft 25 connected to the rotor 24 via the motor-side rotating member 24 b rotates, the

curved plates

26 a and 26 b revolve around the rotation axis of the 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 cause the

curved plates

26 a and 26 b to rotate in the direction opposite to the rotation of the 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 hub bearing portion C via the wheel-side rotating member 28.

At this time, since the rotation of the input shaft 25 is decelerated by the deceleration unit B and transmitted to the wheel side rotation member 28, even when the low torque, high rotation type motor unit A is employed, the torque required for the drive wheels 14 Can be transmitted.

Note that the reduction ratio of the reduction part B having the above-described configuration is calculated as (ZA−ZB) / ZB, where ZA is the number of outer pins 27 and ZB is the number of waveforms of the

curved plates

26a and 26b. In the embodiment shown in FIG. 5, since ZA = 12, ZB = 11, the reduction ratio is 1/11, and a very large reduction ratio can be obtained.

In this way, by adopting the 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 on the outer pin 27 and the inner pin 31, the frictional resistance between the

curved plates

26a and 26b is reduced, so that the transmission efficiency of the speed reducing portion B is improved.

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

In the above-described embodiment, the example in which the lubricating oil supply port 53 is provided in the

eccentric portions

25a and 25b has been shown, but the present invention is not limited to this, and the lubricating oil supply port 53 can be provided at any position of the input shaft 25. However, from the viewpoint of stably supplying the lubricating oil to the rolling bearing 41, it is desirable to provide the lubricating oil supply port 53 in the

eccentric portions

25a and 25b.

Further, in the above-described embodiment, two

curved plates

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

Moreover, although the motion conversion mechanism in the said embodiment showed the example comprised by the inner pin 31 fixed to the wheel side rotation member 28, and the through-hole 30a provided in the

curve boards

26a and 26b, Without being limited to the above, it is possible to adopt an arbitrary configuration capable of transmitting the rotation of the speed reduction unit B to the wheel hub 32. For example, it may be a motion conversion mechanism composed of an inner pin fixed to a curved plate and a hole formed in the wheel side rotation member.

The description of the operation in the above 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. Therefore, the power decelerated as described above is converted into high torque.

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

In each of the embodiments described above, an example in which a radial gap motor is adopted as the motor part 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 housing and a rotor disposed at a position facing the inner side of the stator with a gap in the axial direction.

Further, in each of the above-described embodiments, the example of the in-wheel motor drive device 21 in which the cycloid reduction mechanism is adopted for the reduction part B is shown, but the present invention is not limited to this, and any reduction mechanism can be adopted. For example, a planetary gear reduction mechanism, a parallel shaft gear reduction mechanism, or the like is applicable. Moreover, this invention is applicable also in the in-wheel motor unit (motor direct drive) without a reduction gear.

Furthermore, although the electric vehicle 11 shown in FIG. 3 has shown the example which used the rear wheel 14 as the driving wheel, it is not restricted to this, The front wheel 13 may be used as a driving wheel and may be a four-wheel driving vehicle. . In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and should be understood as including, for example, a hybrid vehicle.

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

21 In-wheel motor drive device A Motor part B Reduction part C Wheel hub bearing part 22 Housing 22b Reduction part housing 32 Hub wheel 33 Fixed wheel 51 Built-in pump 61 Cooling pipe 62 Lubrication pipe

Claims

In the in-wheel motor drive device having a motor unit for generating wheel driving force in the wheel, a pipe constituting a cooling water channel for internal cooling or an oil channel for lubricating oil is provided in the housing of the motor unit. An in-wheel motor drive device formed by insert molding.
2. The in-wheel motor drive device according to claim 1, wherein the housing is made of a cast product of light metal, and a pipe material that becomes a pipe is cast at the time of casting.
The in-wheel motor drive device according to claim 1 or 2, wherein the pipe is used as a cooling pipe through which a liquid for cooling the motor section flows.
4. The in-wheel motor drive device according to claim 3, wherein the cooling pipe communicates with the outside of the motor unit.
5. The in-wheel motor drive device according to claim 3, wherein the cooling pipe is arranged in one turn or a spiral shape in a circumferential direction of the housing of the motor unit.
The in-wheel motor drive device according to claim 1 or 2, wherein the pipe is used as a lubrication pipe through which lubricating oil flows.
The in-wheel motor drive device according to claim 6, wherein the lubrication pipe is also used for cooling the motor unit.
The in-wheel motor drive device according to claim 6 or 7, wherein the lubrication pipe is provided so as to circulate inside the device without communicating with the outside of the device.
The in-wheel motor drive device according to any one of claims 6 to 8, wherein the lubrication pipe is arranged in a radial direction and an axle direction.
The in-wheel motor drive device according to claim 1 or 2, wherein both the cooling pipe and the lubricating pipe are installed.
The in-wheel motor drive device according to any one of claims 6 to 10, wherein a built-in pump for circulating the lubricating oil in the lubrication pipe is installed in the device.
The number of rotations of the built-in pump is set to be the same as the number of rotations of the motor unit when the reduction unit of the motor unit is not provided, and different from the number of rotations of the motor unit when the reduction number of the motor unit is provided. The in-wheel motor drive device according to any one of claims 6 to 11.