JP2019194054A - In-wheel motor drive device - Google Patents

Abstract

To provide an in-wheel motor drive device which can achieve compactness and cooling performance.SOLUTION: An in-wheel motor drive device D includes an in-wheel motor (IWM) 5 which has a rotor 34 for driving a wheel and a stator 33 fixed to a knuckle 13 and is housed in a rim 22 of the wheel. The in-wheel motor drive device D has a heat pipe 40 including: a heat exchanger 43 which can cool a working fluid filling a housing chamber R which houses the stator 33; and pipe-like recirculation passages 41, 42 which allow the working fluid to recirculate from a lead-out part 31a formed at an upper part of the housing chamber R to an introduction part 31b formed at a lower part of the housing chamber R and in which the heat exchanger 43 is disposed in a middle part. The heat exchanger 43 is disposed at an area of the rim 22 which is located at the opposite side of a brake caliper 26 with respect to a wheel center.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an in-wheel motor drive device including an in-wheel motor in an inner peripheral space of a wheel rim.

2. Description of the Related Art Conventionally, an in-wheel motor driving device in which an electric motor for driving is housed in an inner peripheral space of a wheel rim has been known for the purpose of increasing the power transmission efficiency of a vehicle.
When the in-wheel motor drive device is operated under a high load or high rotation state, the temperature of the in-wheel motor (electric motor for driving), particularly the stator including the coil, rises rapidly. There are concerns about component damage and the like due to a decrease in oil viscosity.
In general, a water-cooled cooling mechanism that circulates water from the outside to the part to be cooled can ensure high cooling performance, but there is a structural problem in that the size of equipment such as heat exchangers and piping is increased. ing.

The heat pipe, which is one form of the cooling mechanism, can use a non-fluorocarbon refrigerant and is advantageous in that it is compact and does not require power. Widely adopted. The heat transport capability of this heat pipe is affected by five factors: viscosity limit, sound speed limit, capillary limit, scattering limit, and boiling limit.
Since hydrofluoroether (HFE), which is a halogenated hydrocarbon, has extremely low viscosity and high electrical insulation and thermal stability, it is a refrigerant capable of improving the heat transport capability of the heat pipe. It is.

The wheel drive device for vehicles of patent documents 1 has a rotor which drives a wheel, an outer case which accommodates this rotor and a stator, and was fixed to a knuckle member, and the 1st-3rd cooling device, The cooling device is constituted by a first heat pipe connected between the stator and a lid for closing the opening of the outer case, and the second cooling device is constituted by a second heat pipe connected between the stator and the outer case, 3 The cooling device is constituted by a third heat pipe in contact with the outer case.
The motor of Patent Document 2 includes a stator, an oil passage that supplies oil to the stator, and a heat pipe. The heat pipe is disposed between the motor outer periphery and the motor case and is in contact with or close to the stator. A heat receiving portion provided in the oil passage and a heat radiating portion provided outside the oil passage.

JP 2006-282158 A JP 2008-072881 A

By adopting the heat pipe using HFE as a refrigerant (working fluid) as described above, it is possible to increase the thermal reliability and operating efficiency of the in-wheel motor as compared with the conventional heat pipe.
However, even if the refrigerant performance of the hydraulic fluid used in the heat pipe is improved, the heat pipe itself possesses from the aspect of structural factors related to the capillary limit among the above five elements that affect the heat transport capability of the heat pipe. There is a possibility that the cooling performance cannot be sufficiently exhibited.

Since the vehicle wheel drive device of Patent Literature 1 physically contacts the stator, which is a cooling target, and the heat pipe, when cooling a wide range, the heat pipe may become large or complicated.
In addition, since the working fluid, which is a refrigerant, is in contact with the stator via the heat pipe components (the pipe connection portion and the heat pipe outer wall), the time required for heat exchange becomes longer, and the heat between the stator and the working fluid is increased. The exchange is not performed sufficiently, and there is concern about the diffusion of heat to the surroundings.
On the other hand, in the motor of Patent Document 2, since the heat receiving portion of the heat pipe is disposed in the oil passage of the oil supplied to the stator, the stator and the heat pipe are physically and spatially separated, and the cooled oil Drops (moves) and adheres to the stator, and as in Patent Document 1, heat exchange between the stator and the working fluid is indirect. Moreover, since the cooling performance of the heat pipe depends on the performance of the oil pump that circulates the oil, it is not easy to sufficiently exhibit the cooling performance of the heat pipe.

That is, none of the techniques performs direct heat exchange between the stator and the hydraulic fluid, and it is difficult to obtain sufficient cooling performance.
In addition, due to layout requirements, when the cooling mechanism is arranged close to the brake disc or brake caliper, it may be affected by heat from the brake disc or brake caliper, which is a heat generation source, leading to deterioration of the function of the cooling mechanism. .
Therefore, further improvement is required for the cooling performance of the in-wheel motor drive device.

  The objective of this invention is providing the in-wheel motor drive device etc. which can make compactness and cooling performance compatible.

  The in-wheel motor drive device according to claim 1 includes an in-wheel motor having a rotor connected to the wheel and a stator supported by a knuckle member of the suspension and housed in an inner circumferential space of the rim of the wheel. In the in-wheel motor drive device, a brake disc fixed to a hub provided at an outer end in a vehicle width direction of the shaft of the rotor, a brake caliper fixed to the knuckle member and capable of braking the brake disc, A heat pipe that houses the stator and includes a heat exchanger that can cool the working fluid filled in the annular housing chamber coaxial with the rotor shaft, and the heat exchanger has an inner periphery of the rim. In the side space, it is arranged in a region opposite to the brake caliper with respect to the wheel center.

This in-wheel motor drive device has a heat pipe that includes a heat exchanger that houses the stator and can cool the working fluid filled in an annular housing chamber that is coaxial with the rotor shaft. Direct heat exchange between the stator and the working fluid can be performed.
Since the heat exchanger is disposed in a region opposite to the brake caliper with respect to the wheel center in the inner circumferential space of the rim, the wheel is secured while maintaining a separation interval between the heat exchanger and the brake caliper. An in-wheel motor and a cooling mechanism can be disposed in the rim.

The invention of claim 2 is characterized in that, in the invention of claim 1, the shaft of the rotor is arranged coaxially with the wheel center.
According to this configuration, it is possible to reduce the size and weight by omitting the speed reduction mechanism from the rim of the wheel.

According to a third aspect of the present invention, in the first or second aspect of the invention, the heat pipe connects a lead-out portion provided at an upper portion of the storage chamber and an introduction portion provided at a lower portion of the storage chamber. It has a pipe-like reflux passage that is routed outside the in-wheel motor and through which the hydraulic fluid can flow, and the heat exchanger is disposed in the middle of the reflux passage. It is said.
According to this configuration, the working fluid in the storage chamber can be stirred by the refluxed working fluid, and the heat exchange efficiency between the stator and the working fluid can be improved.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the recirculation passage has a passage length from the lead-out portion to the heat exchanger that is a passage length from the heat exchanger to the introduction portion. It is characterized by being formed to be shorter.
According to this configuration, the backflow of the hydraulic fluid in the upstream passage to the heat exchanger can be suppressed, and normalization of the heat pipe cooling cycle can be ensured.

The invention of claim 5 is the invention according to any one of claims 1 to 4, wherein the in-wheel motor is housed in a rim of a front wheel supported by a double wishbone suspension. .
According to this configuration, it is possible to limit the displacement other than the vertical direction by the upper arm and the lower arm, and it is possible to avoid the interference between the power supply line and the suspension constituent member.

  According to the in-wheel motor drive device of the present invention, both compactness and cooling performance can be achieved.

1 is a layout diagram of a hybrid vehicle according to a first embodiment. It is the perspective view which looked at the right front wheel from the left front. It is the perspective view which looked at the right front wheel from the left rear. It is a left view of a right front wheel. It is a longitudinal cross-sectional view of a right front wheel. It is the perspective view which looked at the in-wheel motor from the right front. It is the perspective view which looked at the in-wheel motor from the left front. It is a longitudinal cross-sectional view of an in-wheel motor. It is explanatory drawing of a heat pipe. It is another explanatory view of a heat pipe. It is explanatory drawing of the displacement locus | trajectory of the electric power feeding line accompanying steering. 6 is a left side view of a right front wheel according to Embodiment 2. FIG. FIG. 7 is a diagram corresponding to FIG. 6 according to the second embodiment. FIG. 9 is a diagram corresponding to FIG. 7 according to the second embodiment. FIG. 9 is a diagram corresponding to FIG. 8 according to the second embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

Embodiment 1 of the present invention will be described below with reference to FIGS.
As shown in FIG. 1, the vehicle V of the present embodiment is a hybrid vehicle on which an in-wheel motor drive device D is mounted.
In the description of the in-wheel motor drive device D, the premise structure of the vehicle V will be described.
The vehicle V is an FR (Front engine Rear drive) vehicle in which an engine 3 that is an internal combustion engine is mounted at the front of a vehicle body and that drives a pair of left and right rear wheels 2 that are main drive wheels.
The rear wheels 2 of the main drive wheels are also driven by a main drive motor 4 instead of the engine 3, and the pair of left and right front wheels 1 that are sub drive wheels are in-wheel motors (hereinafter, IWM) that are sub drive motors. 5) is driven to a predetermined operation region.
The engine 3 and the main drive motor 4 are connected via a clutch (not shown) so that the fastening can be released.

The engine 3 is configured as a flywheel-less engine in which a flywheel is omitted, and drives the rear wheel 2 via a power transmission mechanism 6.
The power transmission mechanism 6 includes a propeller shaft 6a, a clutch 6b, a transmission 6c as a stepped transmission connected to the rear wheel 2 via an axle (not shown), and the like.
The main drive motor 4 is constituted by, for example, a 25 kW permanent magnet synchronous motor (PM motor) driven by 48V, and an inverter 7 for converting the current of a 48V battery 8 (for example, a 3.5 kWh lithium ion battery). Is supplied with alternating current.
The main drive motor 4 is connected in series with the engine 3, and the drive force generated by the main drive motor 4 is transmitted to the rear wheel 2 through the power transmission mechanism 6, similarly to the drive force of the engine 3.
The IWM 5 is configured by, for example, a 17 kW three-phase induction motor (SR motor) driven at 120 V, and an alternating current is supplied from an inverter 10 d that converts the current of the capacitor 10 a.

The control device 9 controls the engine 3, the main drive motor 4 and the IWM 5.
As shown in FIG. 1, a high-voltage DC / DC converter 10b and a low-voltage DC / DC converter 10c, which are voltage converters, are disposed in the vicinity of the capacitor 10a.
The capacitor 10a, the high voltage DC / DC converter 10b, the low voltage DC / DC converter 10c, and the inverter 10d are unitized to form an integrated unit 10.

When the EV mode is selected by a changeover switch (not shown), the control device 9 drives the vehicle V only by the main drive motor 4 at the time of start and at low speed travel, and at the time of acceleration travel in the high vehicle speed region, the IWM 5 The main drive motor 4 and the IWM 5 cooperate to drive the vehicle V.
Further, during deceleration, the main drive motor 4 and the IWM 5 function as a generator and regenerate kinetic energy to generate electric power. The electric power regenerated by the main drive motor 4 is accumulated in the battery 8, and the electric power regenerated by the IWM 5 is accumulated in the capacitor 10a.
When the charge of the capacitor 10a is insufficient, the voltage of the battery 8 is boosted to charge the capacitor 10a. When the voltage between the terminals of the capacitor 10a rises excessively, the charge of the capacitor 10a is lowered to charge the battery 8 Yes.

Next, the front wheel 1 and the front suspension device that supports the front wheel 1 will be described.
This front suspension device is accommodated on the outer side in the vehicle width direction of a wheel house (not shown) formed corresponding to each of the pair of front wheels 1.
As shown in FIGS. 2 and 3, the front suspension apparatus of the present embodiment is of a double wishbone type, and includes an upper arm 11 pivotally supported by an upper body member (not shown) so as to be pivotable up and down, and a subframe. A lower arm 12 pivotally supported by a front member (not shown) of the upper arm 11, a knuckle member 13 rotatably attached to the upper arm 11 and the lower arm 12, a shock absorber 14 extending in the vertical direction, and the like. Yes.
Since the front wheel 1 and the front suspension device that supports the front wheel 1 have a bilaterally symmetric structure, the structure on the right side will be mainly described below.
Also, in the figure, the arrow F direction is the forward direction, the arrow L direction is the left direction, and the arrow U direction is the upward direction.

As shown in FIGS. 2 to 5, the knuckle member 13 supports the front wheel 1, the brake disc 25, and the like so as to be rotatable around the virtual kingpin axis. The knuckle member 13 is formed in a substantially bowl shape opened to the inner side in the vehicle width direction, and an upper end portion and a lower end portion thereof are pivotally supported by the upper arm 11 and the lower arm 12, respectively. The shock absorber 14 includes a damper and a coil spring, the upper ends of which are fixed to a suspension tower (not shown), and the lower end of the damper is rotatably attached to the lower arm 12.
This front suspension device is attached via a steering gear unit (not shown) extending in the vehicle width direction and a rotatable connecting portion extending outward from the steering gear unit to the front side of the knuckle member 13. A tie rod 15 is provided.
By operating a steering wheel (not shown) linked to the steering gear unit, the tie rod 15 moves to the left and right, and the front wheel 1 is steered through the knuckle member 13.

As shown in FIGS. 4 and 5, the front wheel 1 includes a tire 21, a cylindrical rim 22 on which the tire 21 is mounted, and a substantially disc-shaped wheel disk disposed on the outer side in the vehicle width direction of the rim 22. 23 and a disc-shaped hub 24 fixed to a central portion of the wheel disk 23 via a plurality of fastening members. These rim 22, wheel disc 23, hub 24 and the like constitute the wheel of the front wheel 1.
A hollow disc-like brake disc 25 is fixed to the outer side of the hub 24 in the vehicle width direction.
The brake caliper 26 is disposed behind the IWM 5.
The brake caliper 26 is fixed to the rear portion of the knuckle member 13 and is configured to be able to brake the rear portion of the brake disc 25. Reference numeral 27 denotes a heat shielding protective cover provided on the inner side in the vehicle width direction of the brake disc 25.
As described above, the IWM 5, the brake disc 25, the brake caliper 26, and the like are accommodated in the radially inner space of the rim 22.

Next, the in-wheel motor drive device D will be described.
The in-wheel motor drive device D includes an IWM 5 provided on each front wheel 1 and a heat pipe 40 as a cooling mechanism provided corresponding to each IWM 5.

The IWM 5 is supported by the knuckle member 13 in a state where the right side portion is partially surrounded by the knuckle member 13 in the radially inner space of the rim 22.
This IWM 5 rotates and drives a substantially cylindrical outer case 31 with a bottom end on the right side, a lid 32 that closes the left end of the outer case 31, a stator 33 that is a stator, and a front wheel 1. A rotor 34 as a rotor to be rotated and a seal member 35 are main components.
The IWM 5 is an inner rotor type induction motor in which a rotor 34 provided in a radially inner space of the stator 33 rotates.

As shown in FIGS. 6 to 8, on the radially outer side of the outer peripheral wall 31c of the outer case 31, three electrode terminal extraction portions 31u, 31v, 31w are formed at positions corresponding to the upper and virtual kingpin axes, Two pairs of attachment portions 31d are formed on the front upper and lower sides and the rear upper and lower sides.
The electrode terminal extraction portions 31u, 31v, and 31w are electrically connected to motor-side power supply lines 51, which will be described later, and the two pairs of attachment portions 31d are fastened and fixed to the left wall portion of the knuckle member 13 via fastening members, respectively. Has been. A flange portion 31f protruding outward in the radial direction is formed at the left end portion of the outer peripheral wall 31c, and the lid 32 is fastened and fixed to the flange portion 31f.

As shown in FIG. 8, a stator 33 is formed integrally with the outer peripheral wall 31 c on the radially inner side of the outer peripheral wall 31 c of the outer case 31 so as to surround the periphery of the rotor 34.
The stator 33 has a stator coil 33a composed of a U-phase coil, a V-phase coil, and a W-phase coil attached to the inner periphery of the outer peripheral wall 31c by distributed winding.
The rotor 34 has a rotor shaft 34s and a rotor coil 34a attached around the rotor shaft 34s by distributed winding. The rotor coil 34a and the stator coil 33a are provided with an electrically insulating coating (for example, enamel coating).
The rotor coil 34a is disposed to face the stator coil 33a so that an induced current is generated by a rotating magnetic field generated by the stator coil 33a.

The rotor shaft 34s is provided such that the center of the front wheel 1 is positioned on the axial extension line. The IWM 5 is assisted and driven only during specific acceleration travel, so that the IWM 5 is compact and the speed reduction mechanism is omitted.
The left side portion of the rotor shaft 34 s is supported by the outer case 31 by a pair of left and right bearings b 1, and the right side portion is connected to an inner race 24 a formed integrally with the hub 24. The inner race 24a is rotatably supported by the knuckle member 13 via the bearing b2 and the outer race 24b.

As shown in FIG. 8, the seal member 35 is formed in a substantially hat shape in the longitudinal section, and forms a ring-shaped accommodation chamber R that accommodates the stator 33 in cooperation with a part of the outer case 31 including the outer peripheral wall 31c. is doing. The seal member 35 is made of a non-magnetic material (aluminum, carbon, or the like), and seals between the stator coil 33a and the rotor coil 34a in a liquid-tight manner.
The accommodating chamber R is filled with a hydraulic fluid having electrical insulation properties, for example, hydrofluoroether (HFE) so as to immerse the stator coil 33a as a whole.
In this embodiment, the seal member 35 forms the radially inner end wall and the left end wall of the storage chamber R, and the outer case 31 forms the radial outer end wall and the right end wall of the storage chamber R.
In addition, stainless steel, which is a weak magnetic material, can be used as the seal member 35.

Next, the heat pipe 40 as a cooling mechanism will be described.
As shown in FIGS. 4 and 9, the heat pipe 40 includes pipe-like upstream and downstream passages 41 and 42 (reflux passage), a heat exchanger 43 corresponding to a heat radiating portion to the outside, and a stator 33 (stator coil). 33a) is configured by a storage chamber R or the like corresponding to a heat receiving portion that receives heat from 33a).
In the heat pipe 40, the hydraulic fluid heated by the stator 33 takes the latent heat of vaporization and vaporizes, and a pressure difference is generated between the storage chamber R and the heat exchanger 43. And move to the heat exchanger 43. In the heat exchanger 43, the vaporized working fluid condenses and releases an equal amount of latent heat of condensation. The condensed hydraulic fluid flows through the downstream passage 42 by gravity and is returned to the storage chamber R. The cycle of evaporation and condensation is repeated in response to heating and cooling of the hydraulic fluid.

Since HFE has extremely low viscosity due to its nature, it enters between each stator coil 33a attached by distributed winding, and the infiltrated working fluid is vaporized by receiving heat from the entire surface of the stator coil 33a. The boiling point of HFE is about 40 ° C.
As shown in FIG. 10, the accommodation chamber R is formed with a minute gap between the stator coil 33a. For example, a gap of 3 mm is formed at the left end, the right end, and the radially inner end of the stator coil 33a, and the vaporized hydraulic fluid moves to the upper end portion of the storage chamber R through the gap.

As shown in FIGS. 4 and 8 to 10, the upstream passage 41 extends upward from the lead-out portion 31 a formed in the vicinity of the upper end of the storage chamber R, and the downstream passage 42 is the lower end of the storage chamber R. After extending from the introduction part 31b formed in the vicinity to the lower rear side, it extends upward. By arranging the introduction part 31b in the vicinity of the lower end of the storage chamber R, the hydraulic fluid filled in the storage chamber R is stirred using the refluxed hydraulic fluid, and the heat exchange efficiency of the entire cooling mechanism is improved. Yes.
The passage length of the upstream passage 41 is shorter than the passage length of the downstream passage 42.
When the upstream passage 41 is long, the vaporized hydraulic fluid may condense before reaching the heat exchanger 43 and may flow backward in the upstream passage 41, so that the cooling cycle of the heat pipe 40 functions normally in the circulation direction. Because.

As shown in FIGS. 4 and 5, the heat exchanger 43 is disposed in the inner space of the rim 22, specifically, in the space between the outer periphery of the outer case 31 and the inner periphery of the rim 22.
The heat exchanger 43 is disposed in a region opposite to the brake caliper 26 with respect to the wheel center of the front wheel 1 (axial center of the rotor 34), specifically, in a front region and an upper region from the wheel center. This is for securing the arrangement space of the heat exchanger 43 and avoiding heat reception from the brake caliper 26.

As shown in FIGS. 4 and 9, the heat exchanger 43 communicates with the downstream end of the upstream passage 41 and communicates with the upper volume chamber 43 a extending in the front-rear direction in a substantially horizontal manner and the upstream end of the downstream passage 42. A lower volume chamber 43b extending in the front-rear direction in a substantially horizontal manner, a plurality of vertical passages 43c communicating between the upper volume chamber 43a and the lower volume chamber 43b and extending vertically, and a plurality of vertical passages 43c connected to the plurality of vertical passages 43c A cooling fin 43f is provided.
The upper volume chamber 43a is supported on the front upper portion of the knuckle member 13 by the upper bracket 44 (see FIG. 11), and the lower volume chamber 43b is supported on the front portion of the lid 32 by the lower bracket 45.

Next, the power feeding system will be described.
As shown in FIG. 2 to FIG. 4, FIG. 6, FIG. 7, and FIG. 11, the power supply system connects the motor side power supply line 51, the vehicle body side power supply line 52, and the motor side power supply line 51 and the vehicle body side power supply line 52. The movable power supply line 53 and the like are provided so that power can be supplied to the IWM 5 from an in-vehicle power source (not shown).
The motor side power supply line 51 extends rearward along the outer peripheral wall 31c from the bus bars 36u, 36v, 36w connected to the extraction portions 31u, 31v, 31w, and is disposed in the vicinity of the rear end portion of the IWM5. In the connection part 54 (motor side connection part), three feeding lines are bundled into one to constitute a collective electric wire.

The vehicle body side power supply line 52 is connected to a second connecting portion 55 (vehicle body side connecting portion) that extends from the inner wall portion of the wheel house and is locked to the upper arm 11. The second connecting portion 55 is formed to be swingable at a height position equal to or higher than the position near the upper arm 11.
In the present embodiment, as shown in FIGS. 2 and 3, the second connecting portion 55 has a swing shaft formed coaxially with the swing shaft of the upper arm 11 and swings in the vehicle width direction. It is configured freely.
The movable power supply line 53 is formed of a flexible material and is configured as a collective electric wire that can be connected to the first and second connection portions 54 and 55. The movable power supply line 53 is formed in a substantially U-shape that extends rightward and downward from the second connection portion 55 and then curves toward the upper front, and is connected to the first connection portion 54.

  Since the extraction parts 31u, 31v, 31w are arranged at positions corresponding to the virtual kingpin axis, even when the front wheel 1 is steered, the moving locus radius of the extraction parts 31u, 31v, 31w is made as small as possible. . Since the second connecting portion 55 is disposed coaxially with the swing axis of the upper arm 11, the first and second connecting portions are caused by the swinging of the second connecting portion 55 regardless of whether the vehicle V bounces or rebounds. The separation distances 54 and 55 are maintained substantially constant.

As shown in FIG. 11A, when the front wheel 1 is steered to the left side, the first connection portion 54 (the extraction portions 31u, 31v, 31w) is farthest from the second connection portion 55 in plan view. ing.
However, in the neutral state shown in FIG. 11 (b), the movable power supply line 53 is formed in a substantially U shape with respect to the vehicle width direction. Guarantee of steering tracking.
As shown in FIG. 11C, when the front wheel 1 is steered to the right side, the first connection portion 54 is closest to the second connection portion 55 in plan view.
However, since the first connection portion 54 is disposed on the side opposite to the tie rod 15 with respect to the wheel center, the lower end portion is displaced downward without causing interference between the movable power supply line 53 and the tie rod 15, and the movable power supply line 53. Guarantees the ability to follow the steering.

Next, the operation and effect of the in-wheel motor drive device D will be described.
In this in-wheel motor drive device D, a heat pipe 40 that includes a heat exchanger 43 that houses the stator 33 and can cool the working fluid filled in the annular housing chamber R that is coaxial with the rotor shaft 34 s of the rotor 34. Therefore, direct heat exchange between the stator 33 and the hydraulic fluid can be performed.
Since the heat exchanger 43 is disposed in a region opposite to the brake caliper 26 with respect to the center of the wheel in the inner circumferential space of the rim 22, while ensuring a separation distance between the heat exchanger 43 and the brake caliper 26. The IWM 5 and the cooling mechanism (heat pipe 40) can be disposed in the rim 22 of the wheel.

  Since the rotor shaft 34s of the rotor 34 is arranged coaxially with the center of the wheel, the speed reduction mechanism can be omitted from the rim 22 of the wheel, and the size and weight can be reduced.

  The heat pipe 40 is routed outside the IWM 5 so as to connect the lead-out part 31a provided at the upper part of the storage chamber R and the introduction part 31b provided at the lower part of the storage room R, and the working fluid is supplied to the inside thereof. Since the pipe-like reflux passages 41 and 42 that can circulate and the heat exchanger 43 is disposed in the middle of the reflux passages 41 and 42, the working fluid in the storage chamber R is agitated by the refluxed working fluid. Thus, the heat exchange efficiency between the stator 33 and the working fluid can be improved.

  The reflux passages 41 and 42 are formed so that the passage length of the upstream passage 41 from the outlet portion 31a to the heat exchanger 43 is shorter than the passage length of the downstream passage 42 from the heat exchanger 43 to the introduction portion 31b. In addition, the backflow of the hydraulic fluid in the upstream passage 41 to the heat exchanger 43 can be suppressed, and normalization of the cooling cycle of the heat pipe 40 can be ensured.

  Since the IWM 5 is accommodated in the rim 22 of the front wheel 1 supported by the double wishbone type suspension, the displacement other than the vertical direction by the upper arm 11 and the lower arm 12 can be limited, and the power supply lines 51 and 52 and the suspension Interference with components can be avoided.

Next, the in-wheel motor drive device DA according to the second embodiment will be described with reference to FIGS.
In the first embodiment, the rotor 34 provided in the radially inner space of the stator 33 is an inner rotor type IWM 5 that rotates. In the second embodiment, the outer case provided on the radially outer side of the stator 63. 61 is an outer rotor type IWM 5A that rotates.
In addition, the same code | symbol is attached | subjected to the member similar to Example 1. FIG.

As shown in FIG. 12, the IWM 5 </ b> A is supported by the knuckle member 13 in a state in which the right side portion is partially surrounded by the knuckle member 13 in the radially inner space of the rim 22.
As shown in FIGS. 13 to 15, the IWM 5 </ b> A includes a substantially cylindrical outer case 61 whose right end is bottomed, an inner member 62 accommodated in the outer case 61, and a stator 63 that is a stator. And the end wall part 64 which obstruct | occludes the left end part of the outer case 61, and the sealing member 65 are made into the main components. The IWM 5A is an outer rotor type induction motor in which an outer case 61 provided on the radially outer side of the stator 63 rotates.

As shown in FIG. 15, the outer case 61 includes a rotor coil 61a, a substantially cylindrical outer peripheral wall 61b, a seal portion 61c, a rotor shaft 61s, and the like.
The rotor coil 61a is attached to the inner periphery of the outer peripheral wall 61b by distributed winding.
The rotor coil 61a is disposed to face the stator coil 63a so that an induced current is generated by a rotating magnetic field generated by a stator coil 63a described later.
The left end portion of the outer peripheral wall 61b is formed with a seal portion 61c having a larger diameter than the right portion and extending leftward.

The rotor shaft 61s is integrally formed coaxially with the axis of the outer case 61, and has a left half extending into the outer case 61 (left) and a right half extending outside the right outer case 61 (right). is doing. The rotor shaft 61s is provided such that the center of the front wheel 1A is positioned on the axial extension line.
The left half of the rotor shaft 61s is inserted into the inner member 62 and supported by the inner member 62 via a pair of left and right bearings b1.
The right half of the rotor shaft 61s is connected to an inner race 24a formed integrally with the hub 24. The inner race 24a is rotatably supported by the knuckle member 13 via the bearing b2 and the outer race 24b.

As shown in FIG. 15, the inner member 62 includes a substantially cylindrical stator 63 and a substantially annular end wall portion 64 projecting radially outward from the left end portion of the stator 63.
The stator 63 has a stator coil 63a composed of a U-phase coil, a V-phase coil, and a W-phase coil attached to the radially outer portion by distributed winding.
In the end wall portion 64, three electrode terminal extraction portions (not shown) are formed at positions corresponding to the virtual kingpin axis on the radially inner portion, and the motor side power supply line 51A (see FIG. 12) is connected to the bus bars 66u, 66v. , 66w (see FIG. 14), respectively.
A seal portion 64c that is bent rightward and faces the seal portion 61c is formed at the outer end portion of the end wall portion 64. The seal portion 64c and the seal portion 61c are sandwiched by a dust seal 67 and held in a liquid-tight state. The two pairs of front and rear attachment portions 64d fix the end wall portion 64 (inner member 62) to the left side wall portion of the knuckle member 13 via a fastening member.

The seal member 65 is formed in a substantially hat shape in the longitudinal section, and forms a ring-shaped accommodation chamber RA that accommodates the stator 63 in cooperation with a part of the inner member 62 including the end wall portion 64. The seal member 65 is made of a non-magnetic material and seals between the stator coil 63a and the rotor coil 61a in a liquid-tight manner. The storage chamber RA is filled with hydraulic fluid having electrical insulation properties so that the stator coil 63a is entirely immersed.
In this embodiment, the seal member 65 forms the radially outer end wall and the right end wall of the storage chamber RA, and the inner member 62 forms the radial inner end wall and the left end wall of the storage chamber RA.

As shown in FIG. 15, a lead-out portion 64a and an introduction portion 64b penetrating through the end wall portion 64 are provided in portions corresponding to the position near the upper end and the position near the lower end of the storage chamber RA, respectively.
The lead-out portion 64a communicated with the upstream passage 41A of the heat pipe 40A is formed so as to move upward on the left side, and the introduction portion 64b communicated with the downstream passage 42A is formed so as to move downward on the left side. ing. On the left side of the end wall portion 64, a terminal box 68 that covers the periphery of the lead-out portion 64a, the introduction portion 64b, and the bus bars 66u, 66v, and 66w is mounted.

The power supply system includes a motor-side power supply line 51A, a vehicle-body-side power supply line 52, a movable power-supply line 53 that connects the motor-side power supply line 51A and the vehicle-body-side power supply line 52, and the like. It is configured to be able to supply.
As shown in FIG. 12, the motor-side power supply line 51A extends rearward from the bus bars 66u, 66v, 66w connected to the take-out part, and in the first connection part 54A arranged near the rear end part of the IWM 5A. Three feeding lines are bundled into one.
Thereby, in the outer rotor type IWM5A, both compactness and cooling performance are achieved.

Next, a modified example in which the embodiment is partially changed will be described.
1) In the above-described embodiment, the example in which the IWM is mounted on the front wheel of the FR vehicle has been described. However, the IWM may be mounted on the rear wheel of the FF vehicle. Further, although an example of an SR motor has been described as IWM, at least a three-phase induction motor may be used, and a PM motor may be employed.

2) In the above embodiment, an example of a heat exchanger composed of an upper volume chamber, a lower volume chamber, a vertical member, and fins has been described. However, it is sufficient that at least heat exchange with the outside air is possible, and a single volume chamber is required. It may be. Further, it is sufficient that at least the outlet passage and the introduction passage can be formed, and the passage and the heat exchanger may be used by extending the passage instead of the volume chamber.

3) In the above-described embodiment, the example in which the heat pipe is completely accommodated in the radially inner space of the rim has been described, but at least the heat pipe may be disposed on the radially inner side of the rim. The component member may partially protrude inward in the vehicle width direction from the rim.

4) In the above embodiment, an example of a double wishbone type suspension has been described. However, at least an upper support member and a lower support member may exist, and the present invention may be applied to a strut type suspension or the like.

5] In addition, those skilled in the art can implement the present invention in a form in which various modifications are added to the above-described embodiment or in a form in which each embodiment is combined without departing from the gist of the present invention. Various modifications are also included.

1,1A front wheel 5,5A IWM
13 Knuckle member
22 Rim 25 Brake disc 26 Brake caliper 31a Deriving part 31b Introducing part 33 Stator 34 Rotor 40, 40A Heat pipe 41, 41A Upstream path 42, 42A Downstream path 43 Heat exchanger 61 Outer case 64a Deriving part 64b Introducing part D, DA In-wheel motor drive unit R, RA

Claims (5)

An in-wheel motor drive apparatus comprising an in-wheel motor having a rotor connected to a wheel and a stator supported by a knuckle member of a suspension and housed in an inner circumferential space of the rim of the wheel.
A brake disc fixed to a hub provided at an outer end of the rotor shaft in the vehicle width direction;
A brake caliper fixed to the knuckle member and capable of braking the brake disc;
A heat pipe having a heat exchanger capable of cooling the working fluid filled in the annular housing chamber coaxial with the rotor shaft while housing the stator,
The in-wheel motor drive device according to claim 1, wherein the heat exchanger is disposed in a region opposite to the brake caliper with respect to the wheel center in an inner circumferential space of the rim.   The in-wheel motor drive device according to claim 1, wherein a shaft of the rotor is disposed coaxially with the wheel center. The heat pipe is routed to the outside of the in-wheel motor so as to connect a lead-out portion provided at the upper portion of the storage chamber and an introduction portion provided at the lower portion of the storage chamber, and the operation is performed therein. It has a pipe-like reflux passage through which the liquid can flow,
The in-wheel motor drive device according to claim 1, wherein the heat exchanger is disposed in the middle of the reflux passage.   The recirculation passage is formed so that a passage length from the outlet portion to the heat exchanger is shorter than a passage length from the heat exchanger to the introduction portion. The in-wheel motor drive device of Claim 1. 5. The in-wheel motor drive device according to claim 1, wherein the in-wheel motor is accommodated in a rim of a front wheel supported by a double wishbone suspension.