JPH09117090A - Electric wheel motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric wheel motor in which the cooling capacity can be enhanced without complicating the structure. SOLUTION: The housing 60 of an electric wheel motor 1 is aluminum diecast and comprises an outer case 61, an inner case 62 and a partition case 63 interposed between them. The joint faces between the outer and inner cases 61, 62 and the partition case 63 is applied with a liquid packing about 5μm thick excellent in thermal conductivity. The partition case 63 is fixed with a stator 7 and the heat radiation face of a power transistor 25a mounted on a second board 25 is brought into tight contact with opposite faces on the inside of partition case 63. Consequently. the heat generated in the partition case 63 located in the center of housing 60 is transmitted well to the outer and inner cases 61, 62 through the liquid packing excellent in thermal conductivity and the heat is radiated entirely from the outer surface of housing. Heat is also radiated from the fixing part comprising a threaded hole part 62e to the car body side.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electric wheel motor.

[0002]

2. Description of the Related Art Conventionally, an electric wheel motor of this type has been required to have high output torque while being downsized and lightweight.
In order to meet this demand, it was important to increase the cooling capacity of the electric wheel motor. For example, Japanese Patent Laid-Open No. 2-11
Japanese Patent Application Laid-Open No. 419 and Japanese Patent Application Laid-Open No. 3-155349 disclose a cooling device using a cooling oil.

Further, Japanese Laid-Open Patent Publication No. 1-247218 discloses that a forced air cooling system is used to cool an electric wheel motor.

[0004]

However, in the former case, since the cooling device complicates the structure of the electric wheel motor, it is not suitable for downsizing and weight reduction, and the number of parts increases and the cost increases.

In the latter case, the electric wheel motor used in a vehicle is often used in a bad environment where it is always exposed to dust, rain, and muddy water. Had to complicate the structure.

Therefore, an object of the present invention is to provide an electric wheel motor capable of enhancing the cooling capacity without complicating the structure.

[0007]

In order to achieve the above object, an electric wheel motor according to claim 1 of the present invention is attached to a wheel, and a rotation output of a rotor provided on an inner peripheral side of a stator. In an electric wheel motor for transmitting the electric power to an output shaft connected to the wheel via a gear reducer, a first case accommodating an electric motor including the stator and the rotor, and a second case accommodating the gear reducer. , And a partition case that divides the first case and the second case into three parts, and each of the first, second and partition cases has a housing molded by aluminum die casting, and the partition case has a stator of the electric motor and The heat radiating portion of the control circuit of the electric motor is closely attached, and at the same time, the first
A liquid packing is applied to the joint surface of each of the case and the second case and the partition case, and a mounting portion of the mounted body is formed outside at least one of the first case and the second case. And

An electric wheel motor according to a second aspect of the present invention is the electric wheel motor according to the first aspect, wherein the housing is accommodated in the vehicle body side space of the wheel provided in the vehicle, and the mounting portion is the vehicle body. The first of the side
It is characterized in that it is formed in a case.

An electric wheel motor according to a third aspect is the electric wheel motor according to the first aspect, wherein the first portion of the partition case is so bulged that a mounting portion of the stator is bulged toward the first case. A bus plate that is formed on the opposite surface of the case and connects each of the windings of the stator to each other inside the mounting portion in the radial direction, and the power supplied from outside is supplied to the driving power of the winding. The power control element of the control circuit to be converted to is wired to the bus plate, and the power control element is sandwiched and fixed between the bus plate and the partition case so that the heat radiation surface thereof closely contacts the partition case. It is characterized in that it is configured to.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an electric wheel motor of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical sectional view showing the structure of an electric wheel motor attached to a wheel in the embodiment. As shown in the figure, the electric wheel motor 1 includes a housing 60 arranged inside a wheel 3 on which a tire (wheel) 2 is mounted, and the electric motor 4 is provided in the housing 60.
And a gear reducer 5 for decelerating and outputting the rotation output of the electric motor 4.
And built-in. The rotation output of the electric motor 4 is transmitted to the wheel 3 via the gear reducer 5, and the wheel 3 is rotationally driven by the transmitted rotational force.

The housing 60 is a substantially bowl-shaped outer case 6
A partition case 63 is interposed between the first case (second case) and the inner case 62 (first case). The inner case 62, the partition case 63, and the outer case 61 are integrally fastened and fixed by unillustrated bolts. The outer case 61, the inner case 62, and the partition case 63 are cast by aluminum die casting.

The housing 60 is mounted on the vehicle body side (see FIG. 1).
(In the right direction of FIG. 2), it is housed in the inner space of the wheel, and screw holes 61e and 62e for attaching the electric wheel motor 1 to the mounted body are formed outside the outer case 61 and the inner case 62, respectively. . In the present embodiment, the electric wheel motor 1 is attached to the vehicle body using the screw holes 62e.

FIG. 2 shows an outer case 61 and an inner case 6.
FIG. 6 is a vertical cross-sectional view showing a joint portion between 2 and a partition case 63. In the figure, arrows A1, A2 and A3 indicate outer case 6
1 shows the joint between the partition case 1 and the partition case 63, and the liquid packing having excellent thermal conductivity is 5 μm on these joint surfaces.
It has been applied to a thickness of the order. FIG. 3 is an explanatory view showing an end surface of the partition case 63 viewed from the outer case 61 side. Liquid packing 6 on the joint surface indicated by mesh in the figure
3d is applied.

Similarly, in FIG. 2, arrows B1, B2, B
Reference numeral 3 indicates a joint between the partition case 61 and the inner case 62, and the liquid packing is 5 μm on these joint surfaces.
It has been applied to a thickness of the order. As liquid packing,
In this embodiment, a silicone adhesive sealant (trade name “ThreeBond 1220 series”, ThreeBond Co., Ltd.) is used.

A shaft insertion hole 61a is formed in the center of the outer case 61, and the inside of the outer case 61 (inside the housing 60) is perpendicular to the axial direction isolated from the gear reducer 5. A partition wall portion 61b for forming a space S having a horseshoe-shaped cross section is formed. Inner case 6
Two holes 62a extending from the side of the partition case 63 toward the outer end surface are formed in the side portion of No. 2. A stator mounting portion 63a that bulges toward the inner case 62 is formed on a side portion of the partition case 63, and the stator mounting portion 63a extends in the thickness direction of the partition case 63 so as to be continuous with the hole 62a. One hole 63b is formed. A through hole 63c for inserting (penetrating) the axially long portion of the rotor body 8b in a non-contact state is formed in the center of the partition case 63.

The electric motor 4 is housed in the inner case 62 and is composed of a closed slot iron core.
7, a rotor (rotor) 8 that is rotatably provided inside the stator 7, and an output shaft 9 that outputs the rotational output of the rotor 8 via the gear reducer 5.

The stator 7 has a magnetic pole part core and a yoke part core arranged so as to surround the outside of the magnetic pole part core. The magnetic pole portion iron core is formed by laminating a large number of magnetic thin plates (electromagnetic steel plates) on which a plurality of magnetic pole tooth forming projections radially extending outward from a ring-shaped connecting portion through which the rotor 8 is inserted are formed. It is composed by. The magnetic pole teeth are arranged at equal intervals in the circumferential direction of the connecting portion, and a closed slot is formed between the magnetic pole teeth by the connecting portion.

A three-phase field coil 7d is wound around each magnetic pole tooth via a coil bobbin 7c.
Form a stator winding.

The yoke core is constructed by laminating a large number of ring-shaped magnetic thin plates each having a plurality of cutouts formed in the inner peripheral portion thereof. Each notch in the inner peripheral portion forms a fitting groove, and the tips of the magnetic pole teeth of the corresponding magnetic pole portion iron core are fitted in each fitting groove.

A partition case 63 is provided on the outer peripheral portion of the yoke core.
Is sandwiched between the stator mounting portion 63a and the pressing plate 30,
It is fixed to the stator mounting portion 63a by the bolt 13.

The rotor 8 is provided with a shaft insertion hole 8a, which is a rotation center hole, over the entire axial length of the rotor body 8.
b. A plurality of magnetizing magnets 8c arranged at equal intervals in the circumferential direction are mounted on the outer peripheral portion of the rotor body 8b, and the magnets 8c are arranged on the side surface of the rotor 8 on the partition case 63 side. It is provided at equal intervals in the direction.

The axial length of the inner peripheral portion of the rotor body 8b is longer than the axial length of the outer peripheral portion, and the first gear 5a of the gear reducer 5 is formed at the tip portion thereof. The outer peripheral portion of the rotor main body 8b having a short axial length is rotatably opposed to the inner peripheral portion of the stator 7, and bearings 14a, 14b such as ball bearings are press-fitted at both ends of the inner peripheral portion of the rotor main body 8b. Output shaft 9 through
It is configured to rotate about.

A key 9a and a screw hole 9b for attaching an output transmitted member are formed at one end of the output shaft 9. The intermediate portion of the output shaft 9 is provided with a bearing 18 such as a ball bearing in the shaft insertion hole 61a of the outer case 61, and the other end portion of the output shaft 9 is provided with a bearing 19 such as a ball bearing in a central recess of the inner case 62. Each of them is rotatably supported via. The middle part of the output shaft 9 and the outer case 61
The gap between the shaft insertion hole 61 a and the shaft insertion hole 61 a is sealed by the seal member 27. The output shaft 9 is the shaft insertion hole 8 of the rotor 8.
It rotates while being supported by the bearings 14a and 14b in a.

The electric motor 4 whose main constituent elements are the stator 7 and the rotor 8 is a flat brushless electric motor having a short axial length, and the electric wheel motor 1 as a whole has a dimension in the output shaft 9 direction. It is configured to be short.

The gear reducer 5 is a two-stage reducer having a plurality of (four in the present embodiment) gears 5a, 5b, 5c, 5d. That is, the first gear 5a is integrally formed coaxially with the other end side (the left end side in FIG. 1) of the rotor 8 as described above. Second and third gears 5b, 5c
Are fixed to the same rotary shaft (support shaft) 20 so as to rotate integrally with each other, and the second gear 5b is meshed with the first gear 5a.

The rotary shaft 20 is arranged eccentrically with the output shaft 9 and below the output shaft 9. One end of the rotary shaft 20 rotates in a recess of the partition case 63 via a bearing 21 such as a ball bearing, and the other end of the rotary shaft 20 rotates in a recess of the outer case 61 via a bearing 22 such as a ball bearing. It is supported freely.

The fourth (final stage) gear 5d is fixed to the output shaft 9 so as to rotate integrally with the output shaft 9. The third gear 5c is meshed with the fourth gear 5d.
Therefore, when the rotor 8 rotates due to the action of the rotating magnetic field of the stator 7, the first gear 5a integrally formed with the rotor 8 rotates at the same rotation speed as the rotor 8. The rotation output of the first gear 5a is transmitted to the fourth gear 5d after being decelerated by the second and third gears 5b and 5c, and the output shaft 9 is the same as the fourth gear 5d with the decelerated rotation of the fourth gear 5d. Rotor 8 at
And rotate in the same direction.

For example, when the rotor 8 rotates forward at 750 rpm, the output shaft 9 is decelerated by the gear reducer 5 to 1
It rotates forward at 50 rpm and its reduction ratio is 1/5.

Further, in the space S having a horseshoe-shaped cross section perpendicular to the axial direction, which is isolated from the gear reducer 5 formed by the partition case 63 and the horseshoe-shaped partition wall portion 61b of the outer case 61, the horseshoe shape is formed. The first substrate 23 for forming a control circuit for driving the electric motor 4 formed in accordance with the above is arranged, and is attached to the partition case 63 with the screw 24 as shown in FIG. On the horseshoe-shaped first substrate 23, various circuit elements (for example, a semiconductor for control) forming a control circuit for driving the electric motor 4 are attached. By thus forming the space for installing the control circuit in the housing 60, it is not necessary to provide the installation space for the control circuit outside the housing, and by making this space horseshoe-shaped, the space inside the housing 60 is limited. In space,
It is possible to take a large space for accommodating the control circuit.

The space between the partition case 63 and the electric motor 4 is driven by a signal from a control circuit formed on the first substrate 23 and supplies a drive current to the electric motor 4. The second substrate 25 for forming a drive circuit. Are arranged. FIG. 4 is an explanatory view of a second substrate on which various circuit elements are mounted as seen from a plane. Second
The board 25 is a donut-shaped bus plate whose outer dimensions are smaller than the inner diameter of the stator attachment portion 63a of the inner case 62, and the bus plate is attached to the partition case 63 with screws 25b. Second by screw 25b
The fixed position of the substrate 25 is set to be included in the projection range of the rotor 8 in the direction of the output shaft 9. First substrate 23
And the second substrate 25 are connected by a cable connector (not shown).
Are wired and connected by.

On each surface of the second substrate 25, a plurality of wiring paths (not shown) and through holes connected to the wiring paths are formed. The through holes are arranged at equal intervals along the circumferential direction of the outer peripheral portion of the second substrate 25, and the corresponding end portions 7e of the field coil 7d are penetrated and connected to the through holes. The field coils 7d are connected to each other by connecting and fixing each through hole and the corresponding end 7e of the field coil 7d.

On the surface of the second substrate 25 facing the partition case 63, a plurality of power transistors (power MOSF) for supplying a current to the field coil 7d through its end 7e.
ET) 25a and other circuit elements are attached, and each power transistor 25a and the circuit element are connected to the corresponding printed wiring path by soldering. Each power transistor 25a is connected to the center of the second substrate 25 (output shaft 9
Is arranged radially with respect to the center) of the power transistor 25a, and the heat radiating surface of each power transistor 25a (the surface facing the partition case 63) is closely contacted with the facing surface of the partition case 63 on the inner case 62 side through a silicon material for heat radiation. So that at least a part of its proximity to the partition case 63 is included in the projection range of the rotor 8 toward the output shaft 9 direction.
Attached to.

A control line 32 for supplying a control signal from the outside is connected to the first substrate 23, and the control line 32 is one of the holes 63b of the stator mounting portion 63a of the partition case 63 and the inner case connected to it. It is guided to the outside of the housing 60 through a hole 62 a of 62. Hole 62 of control line 32
A retaining member 33 is attached to the portion located at a, and when the pull-out force acts from the outside, this force is
It is configured so as not to reach the substrate 23 side.

Similarly, on the second substrate 25, a pair of power lines 31 for supplying a DC drive current of the electric motor 4 from the outside.
Are connected, and each power line 31 has a corresponding stator mounting portion 63.
hole 63b of a and hole 6 of the inner case 62 continuing to it
It is guided to the outside of the housing 60 via 2a. A control line 32 is provided at a portion of each power line 31 located in the hole 63b.
Similarly, a retaining member (not shown) is attached,
When a pulling force is applied from the outside, this force does not reach the second substrate 25 side.

Further, on the second substrate 25, three for forward rotation and three for reverse rotation for detecting the position of the rotor 8 of the electric motor 4.
A total of six magnetic detection elements are attached. In this embodiment, the Hall element 26 is used as the magnetic detection element.

The hall elements 26 are arranged at predetermined angular intervals on the second substrate 25 so as to face the magnets 8d mounted on the side surfaces of the rotor 8 in the radial direction.
The rotational position of the rotor 8 is detected based on the detection signal from each Hall element 26. The hall element 26 has three pins, and the three pins are inserted into the holes of the second substrate 25 and soldered.

Further, a ring-shaped sensor holder 29 for holding the Hall element 26 is fitted in the through hole 63c of the partition case 63, and the sensor holder 29 has the through hole 63c.
It is sandwiched between the peripheral portion of c and the second substrate 25. Further, the sensor holder 29 is formed with a notch 29a for accommodating the hall element 26 and a seal ring 28 described later. A notch hole 28a is formed in the seal ring 28 in conformity with the shape of the hall element 26, and the head of the hall element 26 is inserted into the notch hole 28a of the seal ring 28 to be in the notch 29a of the sensor holder 29. In the housed state, the seal ring 28 is sandwiched between the sensor holder 29 and the second substrate 25.

The second substrate 25 is fixed inside the partition case 63 by tightening the screws 25b, and at the same time, the seal ring 28 sandwiched between the sensor holder 29 and the second substrate 25 is also fixed. At this time, each power transistor 25a is sandwiched and fixed such that its heat radiation surface is in close contact with the partition case 63.

As described above, in the electric wheel motor according to the present embodiment, the stator 7 is attached to the partition case 63, and the second substrate 25 is provided on the opposing surface inside the partition case 63.
By closely contacting the heat radiation surface of the power transistor 25a, heat is intensively generated in the partition case 63 part of the aluminum die casting located in the center of the housing 60.
The generated heat is satisfactorily transmitted to the outer case 61 and the inner case 62 of the aluminum die casting through the liquid packing having excellent thermal conductivity, and is radiated from the entire outer surface of the housing. Further, heat is also radiated from the mounting portion configured by the screw hole 62e to the vehicle body side which is tightly adhered to the mounting portion. Therefore, even if a cooling device is not used or forced air cooling is not performed, natural cooling can be sufficiently performed with a simple structure.

In the case of natural cooling, the joint surfaces on both sides of the partition case 63 (A1, A2, A3, B1, B in FIG. 1)
2, B3) is provided with a fiber material such as paper having a thickness of 1 mm and the case where liquid packing is applied as in the present embodiment. As a result, the temperature of the stator winding as a heat source is The temperatures were 113 ° C and 107 ° C, respectively, and the temperature could be lowered by about 6 ° C by using liquid packing instead of fibrous material.

[0042]

According to the electric wheel motor of the first aspect of the present invention, the heat intensively generated in the partition case portion is satisfactorily transferred from the partition case to the first case and the second case through the liquid packing. As a result, heat is radiated from the entire outer surface of the housing, and is also radiated to the mounted body side that is mounted on the mounting part.Therefore, even if a cooling device is not used or forced air cooling is not performed, natural cooling is sufficient to provide sufficient cooling capacity. Can be increased.

According to the electric wheel motor of the present invention, the housing is housed in the vehicle body side space of the wheel provided in the vehicle, and the mounting portion is on the opposite side of the wheel. Since it is formed in the first case on the body side, space can be effectively utilized without taking up space, and it can be easily attached to the vehicle body with a large heat capacity, and the large attachment surface allows efficient heat dissipation. You can

According to the electric wheel motor of the third aspect, the mounting portion of the stator is formed on the surface of the partition case facing the first case so as to bulge toward the first case. , A bus plate for connecting each of the windings of the stator to each other in the radial direction of the mounting portion, and power of the control circuit for converting electric power supplied from the outside into drive power for the windings The control element is wired to the bus plate, and the power control element is sandwiched and fixed between the bus plate and the partition case so that the heat radiation surface thereof is in close contact with the partition case. Since the high-temperature heat-generating parts housed inside can be united and integrated into the partition case, internal heat management and coping can be simplified.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view showing a structure of an electric wheel motor attached to a wheel in an embodiment.

FIG. 2 is a vertical cross-sectional view showing a joint between an outer case 61 and an inner case 62 and a partition case 63.

FIG. 3 is an explanatory view showing an end surface of a partition case 63 viewed from the outer case 61 side.

FIG. 4 is an explanatory view of a second substrate on which various circuit elements are mounted as seen from a plane.

[Explanation of symbols]

 1 Electric Wheel Motor 2 Wheel 3 Wheel 7 Stator 25a Power Transistor 61 Outer Case 61e, 62e Screw Hole 62 Inner Case 63 Partition Case 63d Liquid Packing

Front Page Continuation (72) Inventor Yoshiaki Otani 1-4-1 Chuo, Wako-shi, Saitama Stock Research Institute Honda Technical Research Institute

Claims (3)

[Claims] 1. An electric wheel motor which is attached to a wheel and which transmits a rotation output of a rotor provided on an inner peripheral side of a stator to an output shaft connected to the wheel via a gear reducer, wherein the fixed A first case for accommodating an electric motor composed of a child and the rotor, a second case for accommodating the gear reducer, and a partition case for partitioning the first case and the second case are divided into three parts. The partition case has a housing molded by aluminum die casting, and the stator of the electric motor and the heat radiation portion of the control circuit of the electric motor are closely attached to the partition case, and the first case and the second case are attached. A liquid packing is applied to each joint surface with the partition case, and the liquid packing is applied to the outside of at least one of the first case and the second case. Electric wheel motor, characterized in that the formation of the mounting portion of the body. 2. The housing is housed in the vehicle body side space of the wheel provided in a vehicle, and the mounting portion is formed in the first case on the vehicle body side. The described electric wheel motor. 3. The stator mounting portion is formed on the surface of the partition case facing the first case so as to bulge toward the first case, and each of the stator windings is formed. The bus plates connected to each other are arranged on the inner side in the radial direction of the mounting portion, and the power control element of the control circuit for converting the power supplied from the outside into the drive power of the winding is wired to the bus plate, 3. The electric motor according to claim 1, wherein the power control element is configured to be sandwiched and fixed between the bus plate and the partition case so that a heat radiation surface thereof is in close contact with the partition case. Wheel motor.