JPH04185263A - Cooling apparatus of wheel motor - Google Patents

Abstract

PURPOSE:To effectively cool a coil without limiting an installation space by providing a heat inlet part of a heat pipe to a certain area allowing flow of oil within an oil path cover and arranging a heat radiating part to an empty space outside the oil path cover. CONSTITUTION:An oil sent from an oil reservoir by an oil pump motor is supplied to an oil path. An oil path cover 14 forming the oil path is provided with a cooling fin and when the oil rises through the oil path, the oil path is cooled by heat radiation through the cooling fin. Moreover, the oil path cover 14 is provided with a heat pipe 17. This heat pipe 17 is provided in both right and left sides of the oil path cover 14, its heat radiating part is arranged in the empty space outside the oil path cover and a fin 17a is also provided. In addition, the heat inlet part is arranged in the area allowing flow of oil in the vicinity of an inlet port 14a within the oil path cover in order to take the heat. Thereby, any restriction is not given to the installation space.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooling device for a wheel motor used in an electric vehicle.

[Conventional technology]

In recent years, electric vehicles have been actively developed from the viewpoint of environmental issues. Among these, a method using a wheel motor is known in which a motor is directly connected to each wheel via a speed reducer.

By the way, when trying to directly connect a motor to each wheel via a reducer, it is necessary to prevent the vehicle body, motor, and reducer from interfering with each other when the wheels move up and down or turn. installation space is limited.

Therefore, in order to arrange the motor and reducer within such a restricted space, it is required to make these as small as possible. On the other hand, in an electric vehicle, in order to obtain high output relative to the vehicle weight, the motor must be made smaller and lighter and the output torque of the motor must be increased considerably.

However, if a motor is to have a high output torque with a small U quantity, a large amount of current must be passed through the motor coil, which increases the amount of heat generated by the coil, and there is a risk that the coil may burn out.

Therefore, in order to obtain the target performance of the motor, it is important to suppress the heat generation of the coil during overload and cool it.

FIG. 4 is a diagram showing an example of a wheel motor cooling device already proposed by the applicant.

A stator 8 with a coil 84 wound around the case body 81
3 is fixed, and therein is a rotor 8 that drives the rotating shaft.
2 is supported by a bearing, and the rotation of the rotor is transmitted to an output shaft 97 through a reduction gear 96. Further, the rotation of the rotor is detected by a resolver 95.

An oil pump 86 is provided at the bottom of the case body, an oil passage 89 is formed on the case side wall by a plate 87 and a finned oil passage cover 88, and an input boat 9 is provided at the lower end of the oil passage 89.
0 is provided with an output port 91 at the upper end, the output port 91 opens into an oil passage 92 provided at the upper end of the case, and the oil passage 92 is provided with a discharge port 93.

Cooling oil is supplied by an oil pump 86 from an oil reservoir 85 to an oil path 89 through an input boat 90.
It is cooled while moving up the oil passage 89. The cooled oil is guided from the output port 91 to the oil passage 92 and then to the discharge port 93.
The stator coil 84 is blown directly to cool the coil. The oil that has received the heat from the coil is transferred to the oil guide 9.
While contacting the coil end along line 4, the oil is returned to the oil reservoir.

In this way, an oil passage is formed on the side wall of the case body, the oil is circulated using a pump motor, and the oil is ejected from the oil passage at the top of the case body to the coil, which is a heating element, to remove heat, and the oil guide The wheel motor was cooled using a forced convection method that reduced the oil along the path and released the removed heat to the outside air through the oil path cover.

[Problem to be solved by the invention]

By the way, in order to improve the power performance of electric vehicles,
A large amount of current must be passed through the coil, which increases the amount of heat generated by the coil and creates the possibility of damage to the coil.

Therefore, in order to increase the output of the motor, it is necessary to increase the cooling capacity, and for this purpose, it is important to expand the heat dissipation area, improve the heat transfer rate, and cool the oil. In order to satisfy such functions, the cooling device inevitably becomes large-scale. On the other hand, installation space is limited, and if you try to forcefully install such a cooling device, there is a risk that the cooling device and the vehicle body will interfere with each other due to the wheels turning up and down and left and right. Although a cooling device that can provide heat dissipation performance is desired, it has been difficult to realize this in the past.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a wheel motor cooling device that is compact and provides high heat dissipation performance.

[Action and effect of the invention]

In the present invention, the oil pump motor at the bottom of the case supplies oil from the oil reservoir to the top of the case through the oil passage on the side wall of the case, during which time the oil is cooled by a finned oil passage cover, and further cooled by a heat pipe. The cooled oil is then discharged from the case upper oil passage to the stator coil to cool the coil. The heat pipe can effectively cool the oil by arranging the heat input part in a part of the oil passage cover where the flow rate is high, and by arranging the heat dissipation part in an open space outside the oil passage cover. With such a configuration, it is possible to suppress the axial length of the cooling device and obtain a compact size and high heat dissipation performance. Furthermore, the heat pipe is placed inside the oil passage cover from the oil pump's delivery of oil to the oil jetting toward the coil, and since the oil temperature is high at this location, heat can be efficiently dissipated. Further, since the oil guide is provided so that the oil flows while being in total contact with the heat pipe, which is the heat input part in the oil passage cover, the oil can be efficiently cooled.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a sectional view of a cooling device for a wheel motor according to the present invention.

The case body 10 includes a cylindrical support side housing 11
It has a two-part structure consisting of a wheel-side housing 12 and a wheel-side housing 12, and both are fixed with bolts (not shown). Further, the support-side housing 11 has a plate 13 and a cover 14 fixed to the side opposite to the wheel-side housing 12 with bolts (not shown), and is fixed to a support (not shown) with bolts. Further, an oil pump motor 16 is provided at the bottom, and is configured such that oil is supplied from an oil reservoir 18 at the bottom through an oil passage 1 formed between the plate 13 and the cover 14. An oil seal 19 is provided on the inlet side.

A large number of cooling fins 15 and heat pipes 17 are provided on the outer peripheral surface of the cover 14 . An outlet 1a is formed at the upper end of the oil passage 1 and communicates with an oil passage 2 provided at the upper end of the case, and the oil passage 2 is provided with an oil discharge port 2a. And, inside this case body lO, there is a flat,
An electric motor 20 that grows a hollow rotor 23 is housed, and a planetary gear reduction device 30 is housed in the hollow part of the rotor 23.

A coil 22 is wound around a stator 21 of the electric motor 20. The rotor 23 of the electric motor 20 is composed of a hollow iron core, and a permanent magnet 24 is fixed to the outer periphery of the rotor 23 with a holding band. It is rotatably supported at both ends on the opposite side. In the illustrated example, one end is supported by a ball bearing 41 on the housing 11 side, and the other end is supported by a ring gear 31 of a planetary gear reduction device 30.
It is supported by a ball bearing 42 on the side, and a ring gear 31 of a planetary gear reduction device 30 is press-fitted into the housing 12 and fixed with bolts. Further, the sun gear 33 of the planetary gear reduction device 30 is supported by a ball bearing 43 on the housing 11 side, and the rotor 23 is supported by a ball bearing 43 on the housing 11 side.
A spline is fitted to the hollow inside of the The rotation of the resolver shaft 37 inserted and fixed into the sun gear is caused by the rotation of the resolver 3
6. In addition, the sun gear is hollow, and a lubricating oil passage 3 is provided in this hollow part in communication with the oil passage 2, and lubricating oil is directly supplied through the oil passage 3. 3 to the sun gear hollow portion is sealed by a seal ring 38. The pinion shaft 34 is connected to an output carrier 51 that serves as an output rotating shaft, and is connected to the pinion gear 3
2 is a needle bearing 45 on the pinion shaft 34.
is rotatably supported by a ring gear 31 and a sun gear 33.
They are arranged so that they always mesh with each other.

The output flange 52 is connected to the output carrier 5
A double-row angular bearing 44 is spline-fitted to the outer periphery of the ring gear 1 and fixed so as not to be movable in the axial direction by a nut 53, and is engaged with the pinion gear 32 of the ring gear 31.
Supported by Double row angular bearing 4
4 is supplied with lubricating oil through an oil passage 4, and is sealed with an oil seal 39.

A brake disc plate 56 is spline-fitted to the output flange 52, and a tire 55 is spline-fitted to the output flange 52.
The wheel 54 holding the is attached with bolts and nuts. Since the planetary gear reduction device 30 is disposed using the hollow part of the rotor 23 in this way, the length in the axial direction is shortened, making it possible to be flat, compact, and rotate at high speed, thereby improving acceleration/deceleration performance. Moreover, even if the rotor is flattened and the diameter is increased, there is no problem because a thin wall part is provided on the side of the rotor and it is supported at two points near the outer circumference of the rotor at both ends, so that it is sandwiched from both sides. It is possible to increase the rotor's inclination and reduce fluctuations in the gap between the rotor and the stator.

Next, oil cooling and forced oil circulation will be explained.

Oil sent out from the oil reservoir 18 by the oil pump motor 16 is supplied to the oil path 1. The oil passage cover 14 forming the oil passage 1 is provided with cooling fins 15, and in the process of oil rising through the oil passage 1, the cooling fins 1
Heat is radiated through 5 and cooled. Furthermore, the oil passage cover 15 is provided with a heat pipe 17.

As shown in FIG. 2, which is a front view of the wheel motor cooling device shown in FIG.
4, and the heat radiation part is installed in the open space part of the oil passage cover, and the fins 17a are attached to ensure efficient heat radiation.

As shown in FIG. 3, which is a view of the inside of the oil passage cover from the inside of the cooling device shown in FIG. . That is, oil flows into the oil passage cover 14 through the input capo 14a, but the oil passage is narrow in the vicinity and the flow velocity is high, so the heat input part of the heat pipe 170 is placed in this area to efficiently transfer heat. In addition, an oil guide 14b is provided so that the oil flows evenly to the left and right heat pipes, and the oil flows while being in contact with the heat pipes as a whole.As a result, the heat of the oil is reliably dissipated. It can be taken away and cooled down, and the cooling effect can be enhanced.

The oil thus cooled is guided from the outlet 1a provided at the upper end of the oil passage 1 to the oil passage 2 provided at the upper part of the case 10. Then, the oil is ejected from the outlet 2a of the oil passage 2 toward the coil 22 to cool the coil, and is returned to the oil reservoir 18 while contacting the coil end along the oil guide. Further, the oil ejected from the projection port 2a passes through the oil passage 4 and cools the bearing portion on the ring gear 31 side.

Further, the oil sent to the oil passage 2 is supplied to the hollow rotating portion of the sun gear 33 through the oil passage 3.

The oil supplied to the hollow rotating part of the sun gear 33 is passed through the oil passages 6a and Eib formed in the sun gear 33 by centrifugal force to the pinion shaft 34 and the needle bearing 45.
and lubricates these. In this way, the centrifugal force of the rotating parts causes oil to be ejected to the friction surfaces of the gear reducer tooth surfaces and bearings, thereby reliably lubricating them, thereby extending the life of these parts. .

As described above, the oil pump motor at the bottom of the case supplies oil from the oil reservoir to the top of the case through the oil passage on the side wall of the case, and during this time, the finned oil passage cover and the heat pipe installed on the oil passage cover supply oil. Since the cooling device is designed to cool the oil, the oil can be effectively cooled and the coil can be cooled, and the axial length of the cooling device can be suppressed, making it possible to obtain a compact size and high heat dissipation performance. In addition, heat pipes can be placed within space-saving constraints by arranging the heat input part in a part of the oil passage cover where the flow rate is high, and arranging the heat dissipation part in the open space outside the oil passage cover. Also, since the heat pipe is placed in the area where the oil temperature is high, heat can be dissipated efficiently. Furthermore, since the oil guide is provided so that the oil flows while being in contact with the entire heat pipe, which is the heat input part in the oil passage cover, efficient cooling can be performed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the wheel motor cooling device of the present invention;
FIG. 2 is a front view of the oil passage cover, FIG. 3 is a diagram for explaining the flow of oil within the oil passage cover, and FIG. 4 is a sectional view of a conventional wheel motor cooling device. 1.2.4... Oil passage, 2a... Discharge port, 3... Lubrication oil passage, 6a, 6b... Oil passage, 10... Case,
14...Oil channel cover, 14a...Manpower port, 14
b... Oil guide, 16... Oil pump motor, 17... Heat pipe, 17a... Fin, 18
...Oil reservoir.

Claims (1)

[Claims] (1) A stator around which a coil is wound and fixed to the case side, a hollow cylindrical rotor supported by a bearing on the case side and placed inside the stator, and an output that is supported by a bearing on the case side and has wheels attached to it. A flange, an input gear supported on the rotor side, an output gear supported on the output flange side, a reduction mechanism disposed in the hollow part of the rotor, an oil pump motor provided at the bottom of the case, and the coil Discharge ports are provided facing each other,
An upper oil passage formed in the upper part of the case, a plate provided on the side wall of the case, an oil passage cover with cooling fins that is provided on the side wall of the case and forms a side oil passage with the plate, and a heat input section. A cooling device for a wheel motor, comprising a heat pipe in which a heat pipe is provided inside an oil passage cover in which an oil guide is arranged, and a heat radiation part is provided outside the oil passage cover.