JP2006282158A - Wheel drive device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the configuration and enhance the cooling effect of a cooling device for cooling an in-wheel motor.
A vehicle wheel drive device 20 includes an in-wheel motor 30 and cooling devices 80A and 80B for cooling the in-wheel motor incorporated in a rim of the wheel. The in-wheel motor includes a motor housing 31, an annular stator 32 fixed inside the motor housing, and a rotor 34 disposed rotatably on the stator. The cooling device has a configuration in which the coil portions 33 of the stator and the motor housing are connected to each other while being electrically insulated by heat transfer bodies 82 made of heat pipes.
[Selection] Figure 3

Description

  The present invention relates to a technique for cooling an in-wheel motor with a cooling device in a vehicle wheel drive device in which an electric motor, a so-called in-wheel motor is arranged inside a rim of a vehicle wheel (wheel).

In recent years, in order to simplify the power transmission system from the power source to the wheel and increase the transmission efficiency in the vehicle, development of a technology for arranging an in-wheel motor as a driving source inside the rim of the wheel has been advanced. Yes. Since an in-wheel motor that drives a wheel generates a large amount of heat from a coil, development of a technique for cooling is also underway (see, for example, Patent Document 1).
JP-A-5-169985

A conventional vehicle wheel drive device disclosed in Patent Document 1 will be described with reference to FIG.
FIG. 9 is a schematic diagram of a conventional vehicle wheel drive device (prior art). In the conventional vehicle wheel drive device, an oil pump is provided in an in-wheel motor incorporated in the wheel, and cooling oil is forced to circulate from the oil pump into the in-wheel motor. It is to be cooled.

Specifically, a conventional cooling device for a vehicle wheel drive device includes an oil pump provided in an in-wheel motor and an oil pump motor control device 200 that electrically controls the oil pump.
The oil pump motor control device 200 includes a vehicle speed detected by the vehicle speed sensor 201, an accelerator operation amount detected by the accelerator operation amount sensor 202, and an in-wheel motor (wheel drive motor) detected by the wheel drive motor coil temperature sensor 203. The oil pump motor 205 is controlled by receiving sensor signals of the coil temperature and the oil temperature in the motor detected by the oil temperature sensor 204.

As a result, the amount of cooling oil circulated from the oil pump motor 205 to the inside of the wheel motor can be controlled to cool the coil of the wheel motor.
The oil pump motor control device 200 calculates oil circulation amount calculation means 111 for calculating the circulation amount of the cooling oil based on the sensor signals of the sensors 201 to 204, and based on the signal of the oil circulation amount calculation means 111. Oil pump output control means 112 for controlling the oil pump motor 205 is provided.

  However, the conventional vehicle wheel drive device described above constitutes a cooling device that cools the in-wheel motor by the oil pump provided in the in-wheel motor and the oil pump motor control device 200 that electrically controls the oil pump. Therefore, the cooling device must be a complicated and large-scale device, and there is room for improvement.

In order to sufficiently dissipate the heat generated by the coil portion of the in-wheel motor, it is preferable to increase the heat radiation area of the coil portion. For this purpose, the width (dimension in the axial direction of the motor shaft) and thickness (dimension in the direction perpendicular to the axis) of the coil portion may be set large.
On the other hand, on the inner side of the rim of the wheel, a driving device such as an in-wheel motor and a braking device are arranged in parallel in the wheel width direction of the wheel (axial direction of the axle). For this reason, there exists a limit in setting the dimension of an in-wheel motor large in a ring width direction. Therefore, the heat radiation area of the outer peripheral surface in the coil portion cannot be increased. In order to compensate for this, it is necessary to provide a large-scale cooling device, and further improvements have been demanded.

  This invention makes it a subject to provide the technique which simplifies a structure and improves the cooling effect of the cooling device which cools an in-wheel motor.

  According to the first aspect of the present invention, an in-wheel motor is constituted by a motor housing, an annular stator fixed inside the motor housing, and a rotor rotatably arranged on the stator, and the in-wheel motor is cooled. In a vehicle wheel driving device in which a cooling device is provided and the in-wheel motor and the cooling device are incorporated in a rim of the wheel, the cooling device is electrically connected between the coil portion of the stator and the motor housing by a heat transfer body. It is the structure connected while insulating electrically.

  The invention according to claim 2 is characterized in that, in claim 1, the heat transfer body is constituted by a heat pipe.

  According to a third aspect of the present invention, in the second aspect of the present invention, the coil portion includes a pipe connection portion having heat conductivity, and the pipe connection portion has one end of the heat pipe, and has heat conductivity and electrical insulation. By connecting with an electrical insulating material, one end of the heat pipe is connected to the coil portion.

  According to a fourth aspect of the present invention, in the first aspect, the heat transfer body is configured by an elastic body having thermal conductivity and electrical insulation, and the elastic body is disposed in the motor housing so as to be in contact with the coil portion. It is provided on the inner wall.

  The invention according to claim 5 is characterized in that, in claim 1, claim 2, claim 3 or claim 4, a heat radiating fin is provided on the outer surface of the motor housing.

  The invention according to claim 6 is characterized in that the coil portion is molded with an insulating heat radiating resin forming a heat transfer body.

In the invention according to claim 1, since the coil portion and the motor housing are connected while being electrically insulated by the heat transfer body, the heat generated in the coil portion is transferred from the coil portion to the motor housing by the heat transfer body. It is possible to quickly escape and dissipate from the motor housing to the outside air. Therefore, the heat dissipation of the in-wheel motor can be further improved.
Thus, the cooling effect of an in-wheel motor can be heightened more, ensuring the electrical insulation between a coil part and a motor housing with the cooling device of simple structure.

Furthermore, by connecting the side part of the coil part and the side wall of the motor housing with a heat transfer body, heat can be radiated from the side part of the coil part to the side wall. As a result, the heat dissipation from the side part of the coil part can be enhanced.
Therefore, it is not necessary to increase the width of the coil portion (the dimension in the axial direction of the motor shaft) in order to improve the heat dissipation from the outer peripheral surface of the coil portion. As a result, the in-wheel motor can be reduced in size.

  In the invention which concerns on Claim 2, since the heat exchanger was comprised with the heat pipe, the heat which generate | occur | produced in the coil part can be dissipated more efficiently and rapidly to external air.

  In the invention which concerns on Claim 3, the coil connection part is equipped with the pipe connection part which has heat conductivity, and the end of a heat pipe is made into this pipe connection part by the electrically insulating material which has heat conductivity and electrical insulation. Since it connected, the end of a heat pipe can be more simply connected with respect to a coil part. Moreover, it is possible to sufficiently release heat from the coil portion to the heat pipe while sufficiently ensuring electrical insulation between the coil portion and the heat pipe.

In the invention which concerns on Claim 4, a heat-transfer body is comprised by the elastic body which has heat conductivity and electrical insulation, and this elastic body is provided in the inner wall of a motor housing so that a coil part may be touched. The coil part and the motor housing can be directly connected by an elastic body.
Therefore, the distance from the coil portion to the motor housing can be smaller than when a relatively long member such as a heat pipe is used. As a result, in the motor housing, the dimension in the axial direction of the motor shaft can be reduced, so-called thinning. Therefore, the in-wheel motor can be reduced in size.

  In the invention which concerns on Claim 5, a heat radiation area can be increased by providing a heat sink on the outer surface of a motor housing. As a result, the heat transmitted from the coil portion to the motor housing can be dissipated to the outside air more efficiently and quickly.

  In the invention which concerns on Claim 6, since the coil part is the structure which shape | molded with the insulation heat dissipation resin, the area which contacts the motor housing of a coil part can be enlarged with insulation heat dissipation resin. That is, the area of the stator that contacts the motor housing can be increased, and the cooling effect of the cooling device can be enhanced.

  In addition, since the coil part is molded with an insulating heat-dissipating resin, the number of parts can be reduced by molding (molding) the coil part with the insulating heat-dissipating resin so as to contact the motor housing. In addition, the configuration of the cooling device can be simplified.

  In addition, since the coil part is molded with an insulating heat-dissipating resin, the coil part can be molded with the insulating heat-dissipating resin so as to come into contact with the motor housing. can do.

In addition, since the coil portion is molded with the insulating heat-dissipating resin, the insulating heat-dissipating resin is filled also between the windings constituting the coil portion, and the thermal conductivity between the windings can be improved.
Further, since the coil portion is molded with an insulating heat-dissipating resin, there is no step on the surface of the coil portion, and it is easy to form a side surface that contacts the motor housing.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of a wheel provided with a vehicle wheel drive device according to the present invention. FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1 and shows a configuration of a wheel provided with a vehicle wheel drive device as viewed from the outside in the vehicle width direction.

  As shown in FIGS. 1 and 2, the vehicle wheel 10 is a wheel that is suspended from a vehicle body via a suspension (not shown) or directly, and includes a vehicle wheel drive device 20. The wheel 10 includes a cylindrical rim 11, a tire 12 attached to the rim 11, a hollow disk-shaped disk 13 formed integrally on the inner peripheral surface of the rim 11, and a hub formed integrally at the center of the disk 13. 14 and. The disk 13 and the hub 14 are arranged at positions outside the rim 11 in the vehicle width direction (right side in FIG. 1). Further, the hub 14 includes a vent hole 14a penetrating on the rotation center Wc of the hub 14 (that is, the rotation center Wc of the wheel 10).

  The vehicle wheel drive device 20 transmits the power of the in-wheel motor 30, which is a power source for driving the wheel 10, to the hub 14 of the wheel 10 in the rim 11 (inward diameter) of the wheel 10. The gear mechanism 50 and a disc brake 70 for braking the wheel 10 are incorporated.

  The rotation center Mc of the motor shaft 36 of the in-wheel motor 30 is eccentric by a certain distance Di with respect to the rotation center Wc of the wheel 10. As shown in FIG. 2, when the wheel 10 is viewed from the outside in the vehicle width direction, the rotation center Mc of the motor shaft 36 is on the front upper side or the rear upper side with respect to the rotation center Wc of the wheel 10.

FIG. 3 is a cross-sectional view of the vehicle wheel drive device according to the present invention and is shown corresponding to FIG.
As shown in FIG. 3, the in-wheel motor 30 includes a motor housing 31, an annular stator 32 fixed inside the motor housing 31, a plurality of coil portions 33 attached to the stator 32, and a stator 32. A three-phase brushless comprising a rotor 34 rotatably arranged inside, a plurality of permanent magnets 35 attached to the outer peripheral surface of the rotor 34, a motor shaft 36 attached to the center of the rotor 34, and a resolver 37. It is a motor.

The motor housing 31 is a member that also serves as a fixed wheel support portion that is attached to a vehicle body (not shown) and supports the wheel 10 (see FIG. 1), and is adjacent to each other via a partition wall 41. 42 and a gear storage chamber 43.
The motor storage chamber 42 is a space opened on the opposite side to the gear storage chamber 43 and closed with a lid 44. The stator 32, the coil portion 33, the rotor 34, the permanent magnet 35,. The motor shaft 36 and the resolver 37 can be accommodated. In the motor storage chamber 42, the motor housing 31 can be supported by rotating the motor shaft 36 via a bearing 45 and restricting movement in the axial direction.

  In the present invention, the lid 44 detachably attached to the motor housing 31 with a bolt or the like in order to close the motor housing chamber 42 is considered to be a part of the motor housing 31. The motor housing 31 and the lid 44 are made of a material having thermal conductivity.

The motor shaft 36 protrudes from the motor storage chamber 42 (in the motor housing 31) into the gear storage chamber 43 and includes a pinion 51 formed at the front end. That is, the motor shaft 36 extends from the motor storage chamber 42 into the gear storage chamber 43 through the through hole 41 a opened in the partition wall 41.
Each of the coil portions 33 is an electric element including an iron core 33a, a coil bobbin 33b, and a winding (coil) 33c.
The resolver 37 is a sensor that can perform magnetic pole position detection, speed detection, and rotational position detection.

On the other hand, the gear storage chamber 43 is a space that opens on the opposite side of the motor storage chamber 42 and stores the gear mechanism 50 and stores the lubricating oil Lu. The gear mechanism 50 includes the pinion 51 and an internal gear 52 meshed with the pinion 51.
The internal gear 52 is a member disposed on the rotation center Wc of the wheel 10, and includes a cylindrical boss portion 53 on the rotation center Wc, an annular gear portion 55 having internal teeth 54, and a boss portion 53. This is an integrally molded product in which a disk-shaped disk 56 that connects the gear portion 55 is integrally formed.

  In the gear housing chamber 43, the motor housing 31 supports the outer peripheral surface 55 a of the internal gear 52, that is, the outer peripheral surface 55 a of the gear portion 55 via the bearing 57 so as to be rotatable and restricted in movement in the axial direction. be able to. The bearing 57 is prevented from coming off by a pressing member 58 bolted to the motor housing 31.

  The boss portion 53 of the internal gear 52 protrudes from the gear housing chamber 43 to the outside in the vehicle width direction (right side in FIG. 3), and a hollow disk-shaped wheel mounting disc 61 is splined to the outer peripheral surface of the tip portion. In this configuration, the nut 62 is used to prevent the nut from being detached. Therefore, the wheel mounting board 61 is attached to the boss portion 53 by restricting relative rotational movement and movement in the axial direction.

  As shown in FIGS. 1 and 3, the wheel mounting board 61 includes a plurality of bolts with a brake disk 71 and a hub 14 of the wheel 10 overlapped in this order on the outer surface in the vehicle width direction (right side in FIGS. 1 and 3). 63... And nuts 64. In this way, the brake disc 71 and the hub 14 of the wheel 10 can be attached to the internal gear 52.

  As shown in FIG. 1, the combined structure of the hollow disc-shaped brake disc 71 and the caliper 72 attached to the motor housing 31 forms a disc brake 70. The disc brake 70 is a hydraulic or pneumatic brake mechanism.

  As shown in FIG. 1, in the vehicle wheel drive device 20, the power generated by the in-wheel motor 30 is transmitted from the motor shaft 36 to the hub 14 through a path of the pinion 51 → the internal gear 52 → the wheel mounting board 61. , Transmitted to the wheel 10. In this way, the wheel 10 can be driven by the in-wheel motor 30.

  As shown in FIGS. 1 and 3, according to the vehicle wheel drive device 20, the motor housing 31 is configured such that the outer peripheral surface 55 a of the internal gear 52 to which the wheel 10 is attached is rotatably supported by the motor housing 31. The wheel 10 can be supported. For this reason, the motor housing 31 can also serve as a wheel support portion on the fixed side that supports the wheel 10.

  The wheel 10 can be supported at a position away from the rotation center Wc of the wheel 10 by supporting the outer peripheral surface 55a of the internal gear 52 away from the rotation center Wc by the wheel support portion 31. Therefore, the wheel 10 can be supported more stably by the motor housing 31 (wheel support portion) on the fixed side, and the support rigidity can be increased.

Incidentally, as shown in FIG. 3, the vehicle wheel drive device 20 is provided with three cooling devices (a first cooling device 80 </ b> A, a second cooling device 80 </ b> B, and a third cooling device 90) that cool the in-wheel motor 30. It is characterized by that. As shown in FIGS. 1 and 3, these three cooling devices 80 </ b> A, 80 </ b> B, 90 are configured in the rim 11 of the wheel 10.
First, the first cooling device 80A will be described in detail.

  4 (a) and 4 (b) are configuration diagrams of the first cooling device according to the present invention. FIG. 4 (a) shows an exploded structure of the first cooling device 80A, and FIG. A line section structure is shown. FIG. 5 is a cross-sectional view of a main part of the first cooling device according to the present invention, and is shown corresponding to FIG.

  As shown in FIGS. 3 to 5, the first cooling device 80 </ b> A electrically insulates between the coil portions 33... And the lid 44 by a plurality of heat pipes 82. It is the structure connected while.

  Heat pipe 82 is made of aluminum, stainless steel, copper, or other pipe with a wick made of glass fiber or fine net-like copper wire, or a groove. This is a heat transfer body, that is, a heat transfer promoting means, in which the pressure is reduced and heat transfer is performed by transfer of steam of a heat medium such as Freon, ammonia, water and the like, and transfer of latent heat of evaporation.

More specifically, the first cooling device 80A includes a pipe connection portion 81 and a plurality of heat pipes 82.
The pipe connection part 81 is a hollow disk-shaped heat transfer plate made of a material having thermal conductivity, for example, a copper plate having excellent thermal conductivity, on the side facing the lid 44 among the coil parts 33. This is a configuration provided. More specifically, the coil part 33 ... is provided with the pipe connection part 81 via the elastic body 84 in the coil 33c. Note that there is a certain gap between the coil bobbin 33b and the pipe connection portion 81.

  The elastic body 84 is made of a sheet-like elastic member, such as a gel-like sheet, having heat conductivity and electrical insulation, and having flexibility, elasticity, and adhesiveness. As an example of such an elastic member, “λGEL” (registered trademark) manufactured by Geltech Co., Ltd. is known.

By bringing both surfaces of the sheet-like elastic body 84 into close contact with both the outer peripheral surface of the coil 33c wound around the coil bobbin 33b and the plate surface of the pipe connection portion 81, the heat of the coil 33c is transferred to the pipe connection portion 81. Can be transmitted quickly and efficiently.
The pipe connection part 81 can be easily connected to the coil parts 33... Simply by attaching the pipe connection part 81 to the outer peripheral surface of the coil 33 c via the elastic body 84. Moreover, since the elastic body 84 has flexibility and elasticity, it can sufficiently absorb the assembly accuracy of the pipe connection portion 81 with respect to the coil portions 33... And an excessive external force such as an impact is applied to the connection portion. Even if it acts, it is easy to maintain a good connection state.

For example, as shown in FIG. 3, the position of the lid 44 relative to the motor housing 31 is determined by fitting a fitting convex portion on the back surface into the annular stator 32. When the pipe connection part 81 is connected to the lid 44 with the heat pipe 82... And the coil part 33... Is fixed to the pipe connection part 81 with a bolt or the like, when the motor housing 31 is distorted. An excessive external force can act on the coil portions 33.
On the other hand, since the elastic body 84 is used in the present embodiment, there is no concern that an excessive external force acts on the coil portions 33.

The plurality of heat pipes 82 have one ends 82 a connected to the pipe connection portion 81 and the other ends 82 b connected to the lid 44.
A more preferable connection structure of the heat pipes 82 to the pipe connection portion 81 is as follows. As shown in FIG. 5, in this connection structure, a plurality of recesses 81b are formed at a constant pitch on a surface 81a facing the lid 44 of the pipe connection portion 81, and heat pipes are formed in these recesses 81b. Are inserted into one end 82a of the heat pipes 82 ... and embedded in one end 82a of the heat pipes 82. .

  The electrical insulating material 83 is made of, for example, a powder of magnesium oxide (also referred to as magnesia, which is excellent in thermal conductivity and electrical insulation), and can be fixed by, for example, a binder. Since the heat pipes 82... Are connected to the pipe connection portions 81 by the powdery electrical insulating materials 83... Filled in the recesses 81 b. Moreover, even when an excessive external force such as an impact acts on the connection portion, it is easy to maintain a good connection state.

  In this way, the coil part 33... Is provided with a pipe connection part 81 having thermal conductivity, and the pipe connection part 81 is connected to one end 82 a... Of the heat pipe 82. Since the connection is made by the electrical insulating material 83 having the above, the one ends 82a of the heat pipes 82 can be more easily connected to the coil portions 33. In addition, heat can be sufficiently released from the coil portions 33 to the heat pipes 82 while ensuring sufficient electrical insulation between the coil portions 33 and the heat pipes 82. it can.

  As shown in FIG. 4, the lid 44 is a heat transfer plate made of a material having thermal conductivity, for example, a copper plate having excellent thermal conductivity, and a plurality of radiating fins 44 d... Are provided on the outer surface 44 a at a constant pitch. Prepare. More specifically, the flat outer surface 44a of the lid 44 has a plurality of horizontal grooves 44c ... over the entire surface excluding the edge portion 44b, so that protrusions are formed between these grooves 44c ... Is done. These ridges are the radiation fins 44d.

  By providing the heat dissipating fins 44d on the outer surface 44a of the lid 44 which is a part of the motor housing 31, the heat dissipating area can be increased. As a result, the heat transferred from the coil portions 33 to the motor housing 31 can be dissipated to the outside air more efficiently and quickly.

  A more preferable connection structure of the heat pipes 82 to the lid 44 is as follows. As shown in FIGS. 4 and 5, this connection structure is formed with a plurality of joints 44e... On the lid 44, and the other ends 82b of the heat pipes 82.・ It is a structure that closely contacts. The joint portion 44e is formed of a concave portion that faces the through hole or the pipe connection portion 81. For example, when the joint portions 44e are formed of through holes, the other ends 82b of the heat pipes 82 are fitted into these through holes with almost no gap.

As is clear from the above description, according to the first cooling device 80A, the heat transfer body 82... Is provided between the coil portions 33... Of the outer stator 32 and the motor housing 31 (including the lid 44). Therefore, the heat generated in the coil portions 33... Is quickly released from the coil portions 33... To the motor housing 31 by the heat transfer bodies 82. Can be dissipated into the open air. Therefore, the heat dissipation of the in-wheel motor 30 can be further improved.
As described above, the first cooling device 80A having a simple configuration can further enhance the cooling effect of the in-wheel motor 30 while ensuring electrical insulation between the coil portions 33... And the motor housing 31. it can.

  Furthermore, as shown in FIG. 3, since it is a small first cooling device 80A, it can be easily arranged in an empty space of the motor storage chamber 42 (in the motor housing 31). Therefore, the vehicle wheel drive device 20 including the first cooling device 80A can be easily incorporated into a narrow space in the rim 11 of the wheel 10.

  Furthermore, since the heat transfer bodies 82 are constituted by heat pipes, the heat generated in the coil portions 33 can be more efficiently and quickly dissipated to the outside air.

Further, as shown in FIG. 3, by connecting the side portion of the coil portion 33... And the lid 44 (that is, the side wall of the motor housing 31) with a heat transfer body 84, the coil portion 33. .. It is possible to radiate heat to the lid 44 from the side portion. As a result, the heat dissipation from the side part of coil part 33 ... can be improved.
Therefore, in order to improve the heat dissipation from the outer peripheral surface 33d of the coil portions 33 ..., it is necessary to increase the width of the coil portions 33 ... (dimension in the axial direction of the motor shaft), particularly the width Cw of the iron core 33a. Absent. That is, it is not necessary to increase the heat radiation area of the outer peripheral surface 33d. As a result, the in-wheel motor 30 can be reduced in size.

  As shown in FIG. 3, the second cooling device 80B includes a plurality of heat pipes 82 as heat transfer members between the coil portions 33 of the stator 32 and the partition wall 41 of the motor housing 31. It is characterized in that it is connected while being electrically insulated.

The basic configuration of the second cooling device 80B is the same as that of the first cooling device 80A, and is given the same reference numerals and description thereof is omitted. That is, the second cooling device 80B connects one end to the pipe connection portion 81 provided on the side facing the partition wall 41 of the coil portions 33... And the other end connected to the partition wall 41. And a plurality of heat pipes 82. The other ends 82b of the heat pipes 82 are fitted so as to be in close contact with the joints 41b formed of bottomed holes formed in the partition wall 41.
According to such a second cooling device 80B, the same operations and effects as the first cooling device 80A are exhibited.

  As shown in FIG. 3, the third cooling device 90 is attached to the gear storage chamber 43 side of the partition wall 41 on the rotation center Wc of the wheel 10. More specifically, the third cooling device 90 includes a bottomed cylindrical heat transfer body storage unit 91, a plurality of heat pipes 92 as heat transfer bodies stored in the heat transfer body storage unit 91, and The cap 93 covers the opening of the heat transfer body storage 91.

  The heat transfer body accommodating portion 91 is a heat transfer member made of a material having thermal conductivity, for example, a copper material having excellent thermal conductivity, and is disposed on the rotation center Wc of the wheel 10. Such a heat transfer body accommodating portion 91 is removably attached with the bottom portion in close contact with the partition wall 41 and penetrates through the boss portion 53 of the internal gear 52 to open the opening on the hub 14 (see FIG. 1) side. It is open.

The plurality of heat pipes 92... Have a substantially U-shape, and end portions thereof are joined to the bottom of the heat transfer body storage portion 91 and the bent portions are extended to the vicinity of the opening of the heat transfer body storage portion 91. It is. In addition, these heat pipes 92 ... have the same basic configuration as the heat pipes 82 ... in the first cooling device 80A, and a description thereof will be omitted.
The cap 93 is a substantially cup-shaped member attached by fitting to the opening of the heat transfer body accommodating portion 91, and has a plurality of vent holes 93a.

  According to the third cooling device 90, the heat transferred from the in-wheel motor 30 and the gear mechanism 50 to the partition wall 41 is promptly transferred from the partition wall 41 to the heat transfer body 82 through the heat transfer body storage 91. It is possible to escape and dissipate from the heat transfer bodies 82 to the outside air. Therefore, the heat dissipation of the in-wheel motor 30 and the gear mechanism 50 can be further enhanced.

  Further, as shown in FIG. 1, the third cooling device 90 is arranged because the empty space in the rotation center Wc portion of the wheel 10 in the gear storage chamber 43 is effectively utilized, and thus the third cooling device 90 is arranged. There is no need to provide an extra space for this. For this reason, the wheel drive device 20 for vehicles does not enlarge. Therefore, the vehicle wheel drive device 20 including the third cooling device 90 can be easily incorporated into a narrow space in the rim 11 of the wheel 10.

By the way, as shown in FIG. 3, since the lower part of the gear part 55 and the lower part of the bearing 57 are immersed in the lubricating oil Lu accumulated in the gear housing chamber 43, the lubricating oil Lu is caused by the rotation of the internal gear 52. Thus, the gear mechanism 50 and the bearing 57 can be lubricated and cooled.
Part of the lubricating oil Lu after lubricating the gear mechanism 50 and the bearing 57 is scraped up and scattered by the internal gear 52 and enters the communication hole 36 a from the tip of the motor shaft 36. The lubricating oil Lu in the communication hole 36 a is scattered from the discharge hole 36 b to the motor storage chamber 42 by the centrifugal force accompanying the rotation of the motor shaft 36. The scattered lubricant Lu contacts with each member of the in-wheel motor 30 stored in the motor storage chamber 42 and cools, and then accumulates at the bottom of the motor storage chamber 42. Lubricating oil Lu accumulated at the bottom returns to the gear housing chamber 43 through the side outflow hole 41b.

  As described above, the gear mechanism 50 is cooled while being lubricated by the lubricating oil Lu in the gear housing chamber 43, and the in-wheel motor 30 is also cooled by the lubricating oil Lu introduced from the gear housing chamber 43 into the motor housing chamber 42. can do. That is, the lubricating oil Lu in the gear housing chamber 43 can be shared for cooling the gear mechanism 50 and cooling the in-wheel motor 30.

  Furthermore, since the in-wheel motor 30 is air-cooled by the cooling devices 80A, 80B, 90 and also cooled by the lubricating oil Lu, the in-wheel motor 30 can be cooled more efficiently, and the cooling performance is improved. Moreover, the lubricating oil Lu can be introduced from the gear housing chamber 43 into the motor housing 31 by the gear mechanism 50. Therefore, the in-wheel motor 30 can also be efficiently cooled without providing a lubricating oil supply device made of another member such as a pump.

Next, a modification of the cooling device will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the structure similar to the said 1st cooling device 80A (refer FIG. 5), and the description is abbreviate | omitted.
FIG. 6 is a cross-sectional view of an essential part of the cooling device (modified example) according to the present invention, and shows a modification of the configuration shown in FIG.

As shown in FIG. 6, the cooling device 80C according to the modification is characterized in that the surface of the coil 33c wound around the coil bobbin 33b and the back surface 44f of the lid 44 are directly connected only by the elastic body 84. To do. That is, it is the structure which abolished the pipe connection part 81, the heat pipe 82 ..., and the electrical insulation material 83 ... with respect to the said 1st cooling device 80A (refer FIG. 5).
In the cooling device 80C of the modified example, the elastic body 84 serves as a heat transfer body. This elastic body 84 was provided on the back surface 44f of the lid 44 (that is, a part of the inner wall of the motor housing 31 shown in FIG. 3) so as to contact the coil portion 33.

As described above, according to the cooling device 80C of the modified example, the elastic body 84 is employed as the heat transfer body, and the elastic body 84 is provided on the back surface 44f of the lid 44 so as to be in contact with the coil portion 33. The distance from the coil part 33 to the lid 44 can be smaller than when a relatively long member such as... Is used.
As a result, in the motor housing 31, the dimension in the axial direction of the motor shaft 36 can be reduced, that is, a so-called thin shape. Therefore, the in-wheel motor 30 can be reduced in size.

  Similarly, the second cooling device 80B (see FIG. 5) can be replaced with the cooling device 80C of the modified example.

In the embodiment of the present invention, the in-wheel motor 30 has an inner stator inside the outer rotor, in addition to the inner rotor type in which the rotor 34 (inner rotor) is rotatably arranged inside the annular stator 32 (outer stator). The arranged outer rotor type may be used.
Further, the ends 82a of the heat pipes 82 in the first and second cooling devices 80A and 80B are not limited to the configuration embedded in the recesses 81b of the pipe connection portion 81. For example, the structure fit so that it might closely_contact | adhere to the recessed part 81b ... may be sufficient.

  In addition, the three cooling devices 80A, 80B, 90 are provided on the partition wall 41 and the lid 44 having a relatively large surface area in the motor housing 31 (including the lid 44). This is because a large surface area increases heat dissipation. However, the configuration is not limited to the configuration provided in the partition wall 41 and the lid 44, and any configuration provided in the motor housing 31 (including the lid 44) may be used.

  Moreover, the cooling structure of the in-wheel motor 30 should just be the air cooling by cooling device 80A, 80B, 80C, 90, and it is arbitrary about using together cooling by circulation of lubricating oil Lu.

Next, another embodiment will be described.
FIG. 7 is a cross-sectional view illustrating a vehicle wheel drive device according to another embodiment, and corresponds to FIG. 3.
FIG. 8 is a view taken in the direction of arrow 8 in FIG. The same configurations as those in the embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals and description thereof is omitted.

Another embodiment of the vehicle wheel drive device 101 includes a cooling device 102 that cools the in-wheel motor 30C.
The cooling device 102 includes a heat transfer body 104 disposed between the coil portions 33C of the stator 32C included in the in-wheel motor 30C and the motor housing 31C. Further, the water cooling means 107 disposed on the inner peripheral surface 106 of the peripheral wall portion 105 of the motor housing 31C, the in-wheel heat radiation fin 109 formed on the outer wall portion 108 of the motor housing 31C, and the motor cover (lid) 111 of the motor housing 31C are provided. And the formed heat radiation fin 112 outside the wheel, and cools the stator 32C.

  The stator 32C uses 18 coil portions 33C..., And 18 coil portions 33C... Are arranged in an annular shape and are integrally connected with the insulating heat radiation resin 114 and molded in an annular shape. is there. Reference numeral 116 denotes a stator holder for fixing the stator 32C.

  Specifically, the stator 32C is formed by winding a predetermined number of windings 117 around the iron core 33a via the coil bobbin 33b, thereby forming a coil portion 33C, and 18 coil portions 33C, a pitch angle θ, an outer diameter D, The insulating heat radiating resin 114 was used with an inner diameter d, and was molded by, for example, an injection molding machine. At this time, the insulating heat radiating resin 114 is filled (pitch filling portion 118) between the pitch gap S located at the pitch angle θ, that is, between the coil portion 33C and the coil portion 33C (pitch gap S), and the thickness of the stator 32C is increased. Molded at T (see FIG. 7). At the same time, the winding resin filling portion 121 was formed continuously with the pitch filling portion 118 by filling the gap between the windings 117 with the insulating heat radiation resin 114 and covering the wound winding 117.

Here, a configuration when the heat transfer body 104 is mainly used will be described.
The heat transfer body 104 is an insulating heat radiating resin 114. Specifically, the winding resin filling portion 121 covering the wound winding 117 and the winding resin filling portion 121 are connected to the pitch gap S between the coil portion 33C and the coil portion 33C. Pitch filling part 118 filled and molded, first side heat radiation part 125 connected to pitch filling part 118 and winding resin filling part 121, pitch filling part 118 and winding resin facing first side heat radiation part 125 And a second side heat dissipating part 126 connected to the filling part 121. The distance from the first side heat radiation part 125 to the second side heat radiation part 126 is the thickness T of the stator 32C.

  Further, in a broad sense, the heat transfer body 104 is in close contact with the first side heat dissipating part 125 and in close contact with the motor cover (lid) 111 of the motor housing 31C, and the second side heat dissipating part 126. And a second insulating heat-radiating gel sheet 128 that is in close contact with the outer wall 108 of the motor housing 31C.

The outer diameter of the first and second side heat radiation portions 125 and 126 is D1, and the inner diameter of the first and second side heat radiation portions 125 and 126 is d.
The surface area A1 of the first side heat radiation part 125 is A1 = π (D1 ² −d ² ) / 4.
The surface area A2 of the second side heat radiation part 126 is A2 = A1.

  The insulating heat radiation resin 114 is, for example, a trade name of Showa Polymer Co., Ltd., and is any one of EVC-100M, EVC-200M, EVC-400W, and RNC-970BK. The molding conditions (for example, molding conditions for injection molding) are arbitrary.

The first insulating heat-dissipating gel sheet 127 is the same as the elastic body 84 (see FIG. 3), has thermal conductivity and electrical insulation, and has flexibility, elasticity and adhesiveness, and is outside the wheel of the motor housing 31C. Heat transfer to the radiation fin 112 side is performed.
The surface area of the first insulating heat radiating gel sheet 127 is Ag1, and the surface area Ag1 is in contact with the motor housing 31C. The surface area Ag1 is set to Ag1> A1.
As an example of the material of the first insulating heat radiating gel sheet 127, “λGEL (Lambda Gel)” (registered trademark) manufactured by Geltech Co., Ltd. can be cited.

The second insulating heat radiating gel sheet 128 is the same as the first insulating heat radiating gel sheet 127, and performs heat transfer to the in-wheel heat radiating fin 109 side.
The surface area of the second insulating heat-radiating gel sheet 128 is Ag2, and the surface area Ag2 is in contact with the motor housing 31C. The surface area Ag2 is set to Ag2> A2.

  The in-wheel heat dissipating fin 109 has a radius ru, a pitch Pu, a thickness tu, a center angle α (see FIG. 8), a high height in order from the rotation center Mc of the motor shaft 36 outward in the radial direction. This is a fin molded with Hu.

  The outside-wheel heat radiation fin 112 is a fin formed by sequentially forming the first to sixth fins with a diameter ds, a pitch Ps, a thickness ts, and a height Hs from the rotation center Mc toward the outside in the radial direction.

  The water cooling means 107 includes a cooling water passage 131 carved in the inner peripheral surface 106 of the peripheral wall portion 105 of the motor housing 31C, grooves 132 and 132 formed along the cooling water passage 131, and an O-ring 133 fitted in the grooves 132 and 132. 133, a stator holder 116 that also serves as a lid for the cooling water channel 131, and temperature adjusting means (not shown) for circulating the cooling water 134 through the cooling water channel 131, and the stator holder 116 holds the stator 32C. Accordingly, the iron cores 33a... Brought into contact with the stator holder 116 are water-cooled, and the lubricating oil Lu (see FIG. 3) is water-cooled.

Next, the operation of the vehicle wheel drive device 101 according to another embodiment will be described.
When the temperature of the coil portion 33C... Of the stator 32C rises, heat is transferred to the first side heat radiating portion 125 and the second side heat radiating portion 126 by the insulating heat radiating resin 114, and from the first side heat radiating portion 125 to the first insulating heat radiating gel sheet. The heat is transmitted to the outside-radiation fin 112 by 127, and the outside-radiation fin 112 dissipates heat to the atmosphere. Similarly, heat is transmitted from the second side heat radiation portion 126 to the in-wheel heat radiation fin 109 by the second insulating heat radiation gel sheet 128, and the in-wheel heat radiation fin 109 dissipates heat to the atmosphere. As a result, the temperature rise of the stator 32C can be suppressed.

  Further, the plurality of coil portions 33C are arranged in an annular shape, are integrally connected with the insulating heat radiation resin 114, and are formed into an annular shape, whereby the ring-shaped first side surface heat radiation portion 125 and the second side surface heat radiation portion 126 are formed. Was molded. As a result, the surface area A1 of the first side heat radiation portion 125 can be brought into contact with the motor housing 31C via the first insulating heat radiation gel sheet 127, and the heat radiation area of the stator 32C brought into contact with the motor housing 31C can be increased. Therefore, the cooling effect of the cooling device 102 can be enhanced.

  Similarly, since the second side heat radiating portion 126 is molded, the surface area A2 of the second side heat radiating portion 126 can be brought into contact with the motor housing 31C via the second insulating heat radiating gel sheet 128, and the stator to be brought into contact with the motor housing 31C. The heat radiation area of 32C can be increased. Therefore, the cooling effect of the cooling device 102 can be enhanced.

  As described above, in the vehicle wheel drive device 101 according to another embodiment, the plurality of coil portions 33C (consisting of the iron core 33a, the winding 117, and the coil bobbin 33b) are arranged in an annular shape to insulate the heat radiation resin. 114 is integrally connected and formed into an annular shape, so that the wound winding 117 is covered with the insulating heat-radiating resin 114, the annular stator 32C is formed, and the ring-shaped first side surface heat radiation portion 125 of the stator 32C is formed. Since the first side heat radiation gel sheet 127 is brought into contact with the motor housing 31C and the second side heat radiation part 126 facing the first side heat radiation part 125 is brought into contact with the motor housing 31C via the second insulation heat radiation gel sheet 128, The area of the stator 32C in contact with the motor housing 31C can be increased, and the cooling effect of the cooling device 102 can be enhanced. Can.

  Further, in the vehicle wheel drive device 101 of another embodiment, a plurality of coil portions 33C (consisting of an iron core 33a, a winding wire 117, and a coil bobbin 33b) are arranged in an annular shape with an insulating heat radiation resin 114. By integrally connecting and forming an annular shape, the wound winding 117 is covered with the insulating heat radiation resin 114, the annular stator 32C is formed, and the ring-shaped first side heat radiation portion 125 of the stator 32C is the first. The motor housing 31C is brought into contact with the insulating heat radiating gel sheet 127, and the second side heat radiating portion 126 facing the first side heat radiating portion 125 is brought into contact with the motor housing 31C through the second insulating heat radiating gel sheet 128. The number of parts interposed between 31C and the stator 32C can be reduced, and as a result, the structure of the cooling device 102 can be reduced. It is possible to simplify.

  Since the first and second side heat radiation portions 125 and 126 made of the insulating heat radiation resin 114 included in the stator 32C are brought into contact with the motor housing 31C via the first and second heat radiation gel sheets 127 and 128, respectively, Soundproofing and vibration isolation can be achieved.

  In the vehicle wheel drive device 101 according to another embodiment, the coil portion 33C is molded (molded) with the insulating heat-dissipating resin 114 that forms the heat transfer body 104, so that it is also insulated between the windings 117 that constitute the coil portion 33C. The heat radiation resin 114 is filled, and the thermal conductivity between the windings 117 can be improved.

  Since the coil portion 33C is molded (molded) with the insulating heat radiation resin 114, there is no step on the surface of the coil portion 33C, and the side surfaces (the first side heat radiation portion 125 and the second side heat radiation portion 126) that come into contact with the motor housing 31C are eliminated. Formation becomes easy.

  In the vehicle wheel drive device 101, since the iron cores 33a are brought into contact with the stator holder 116 provided in the water cooling means 107 of the cooling device 102, the iron cores 33a can be cooled with the cooling water 134, and as a result. In addition, the coil portions 33C can be cooled. Therefore, the cooling effect of the cooling device 102 can be enhanced.

  The vehicle wheel drive device 20 of the present invention can simplify the power transmission system from the power source to the wheel 10 by disposing the in-wheel motor 30 as the power source inside the rim 11 of the wheel 10. Therefore, it is suitable for an electric vehicle.

It is sectional drawing of the wheel provided with the vehicle wheel drive device which concerns on this invention. FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1. It is sectional drawing of the wheel drive device for vehicles which concerns on this invention. It is a block diagram of the 1st cooling device which concerns on this invention. It is principal part sectional drawing of the 1st cooling device which concerns on this invention. It is principal part sectional drawing of the cooling device (modification) which concerns on this invention. Sectional drawing explaining the wheel drive device for vehicles of another embodiment Fig. 8 arrow view It is a schematic diagram of the conventional vehicle wheel drive device (prior art).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Wheel, 11 ... Rim, 20, 101 ... Vehicle wheel drive device, 30, 30C ... In-wheel motor, 31, 31C ... Motor housing, 32, 32C ... Stator, 33, 33C ... Coil part, 34 ... Rotor, 44d ... Radiating fins, 80A, 80B, 80C, 102 ... Cooling device, 81 ... Pipe connection, 82 ... Heat transfer body (heat pipe), 82a ... One end of the heat pipe, 82b ... The other end of the heat pipe, 83 ... Electricity Insulating material, 84 ... Heat transfer body, 104 ... Heat transfer body, 109 ... Radiation fin (radiation fin in the wheel), 112 ... Radiation fin (radiation fin outside the wheel), 114 ... Insulation radiation resin, 117 ... Winding, 125 ... 1st side surface heat radiation part, 126 ... 2nd side surface heat radiation part.

Claims (6)

  An in-wheel motor is constituted by a motor housing, an annular stator fixed inside the motor housing, and a rotor rotatably arranged on the stator, and a cooling device for cooling the in-wheel motor is provided. In a vehicle wheel drive device in which a wheel motor and a cooling device are incorporated in a rim of a wheel, the cooling device electrically insulates between a coil portion of the stator and the motor housing by a heat transfer body. A wheel drive device for a vehicle having a connected configuration.   The vehicle wheel drive device according to claim 1, wherein the heat transfer body includes a heat pipe.   The coil part includes a pipe connection part having thermal conductivity, and one end of the heat pipe is connected to the pipe connection part with an electrical insulating material having thermal conductivity and electrical insulation, thereby forming a coil. The vehicle wheel drive device according to claim 2, wherein one end of a heat pipe is connected to the portion.   The heat transfer body is made of an elastic body having thermal conductivity and electrical insulation, and the elastic body is provided on an inner wall of the motor housing so as to be in contact with the coil portion. The vehicle wheel drive device according to claim 1.   5. The vehicle wheel drive device according to claim 1, wherein the motor housing includes a heat radiation fin on an outer surface. 6.   The vehicle wheel drive device according to any one of claims 1 to 5, wherein the coil portion is molded with an insulating heat-dissipating resin that forms the heat transfer body.

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