JP2869926B2 - Wheel motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel motor used for an electric vehicle such as an electric vehicle, a forklift, a golf cart, etc., and more particularly to a wheel motor with a speed reducer which is driven by connecting the motor via a speed reducer.

[0002]

2. Description of the Related Art In a wheel motor with a reduction gear of this type,
In order to prevent the vehicle body from interfering with the motor and the reducer when the wheels move up and down or turn, special measures must be taken when mounting the vehicle. On the other hand, the motor and the planetary gear reducer are installed in the space inside the wheels. A wheel motor has been already proposed in which the rotational output of the electric motor is transmitted to the wheel via the planetary gear reducer to rotate the wheel (see, for example, Japanese Unexamined Patent Application Publication No. Hei. -11419 and JP-A-4-14-1
No. 85207).

[0003]

However, these prior arts employ a planetary gear reducer as a reducer.
The output shaft that transmits the rotation output of the rotor of the electric motor to the wheel via the planetary gear reducer is once separated in the axial direction of the wheel motor, and then the output is taken out with the shaft center aligned. There is a problem that it is difficult to assemble, the support span of the output shaft must be shortened, and the support strength against falling down of a wheel including a tire is low.

[0004] Further, when the electric motor is constituted by a brushless motor, it is necessary to devise a method of mounting a sensor for detecting the position of the rotor, and there is a problem that the structure is further complicated.

Further, since the control circuit for driving the electric motor is mounted on the vehicle body frame side on which the wheel motor is mounted, it is necessary to secure a space for mounting the control circuit on the vehicle body frame side. Between the vehicle body frame and the wheel motor, there are many energizing lines and signal lines connecting the control circuit and the motor, and the length of each energizing line and signal line becomes longer. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object the purpose of having a simple structure, being easy to assemble, and maintaining a favorable environment for a sensor for detecting the position of a magnet rotor. An object of the present invention is to provide a wheel motor capable of increasing the support strength against the fall of a tire because the support span of the output shaft can be made long.

[0007]

According to a first aspect of the present invention, an electric motor and a gear reducer are disposed in a space inside a wheel, and the electric motor is reduced in speed by the gear reducer. A wheel motor configured to rotationally drive the wheel by the rotation output of the motor, wherein the motor is a brushless motor having a magnet rotor, and a first case that accommodates the motor in a space inside the wheel. A housing comprising a second case accommodating the gear reducer and a partition plate for partitioning between the first case and the second case is provided; and the motor is provided on the motor housing side of the partition plate. A stator mounting portion, and a sensor mounting portion for detecting the position of the magnet rotor,
On the gear reducer housing side of the partition plate, a support portion that supports a rotation shaft of a gear of a predetermined stage of the gear reducer arranged eccentrically with the output shaft of the electric motor is formed, and the output shaft of the electric motor is
It is configured to be supported by a first case that houses the electric motor and a second case that houses the gear reducer while penetrating the partition plate.

According to a second aspect of the present invention, in order to attain the above object, there is provided a space between the second case accommodating the gear reducer and the partition plate, wherein the gear reducer is not disposed. A wall for forming a space formed is formed integrally with at least one of the second case and the partition plate, and is configured to accommodate a control circuit for driving the electric motor in the space. .

In order to achieve the above object, according to the third aspect of the present invention, the wall portion in the second aspect defines a horseshoe-shaped space for accommodating the control circuit by an outer wall of the second case and the partition plate. In addition, the output shaft of the electric motor and the gear reducer are configured to be disposed in a space formed inside the horseshoe-shaped space.

[0010]

According to the first aspect of the present invention, the electric motor comprises a brushless motor having a magnet rotor, and a first case accommodating the electric motor and the gear reducer in an inner space of a wheel. The second case and the first
A housing constituted by a partition plate for partitioning between the case and the second case is provided, and a mounting portion of a stator of the electric motor and a position of the magnet rotor are provided on a motor housing side of the partition plate. Attachment portion of the sensor to be detected, on the gear reducer housing side of the partition plate, a support portion that supports a rotation shaft of a gear at a predetermined stage of the gear reducer that is eccentrically arranged with the output shaft of the electric motor, The output shaft of the electric motor is configured to be supported by a first case that houses the electric motor and a second case that houses the gear reducer while penetrating the partition plate. Thereby, the structure is simple and easy to assemble, and the environment of the sensor for detecting the position of the magnet rotor can be maintained in a good condition. It is possible to obtain strength.

According to a second aspect of the present invention, in the first aspect, a separated space in which the gear reducer is not disposed is formed between the second case accommodating the gear reducer and the partition plate. 2 is formed integrally with at least one of the second case and the partition plate, and is configured to house a control circuit for driving the electric motor in the space. In addition to the action of the control circuit, the control circuit is protected from rainwater, mud, etc. by the wheel and the second case, and from the lubricating oil due to the rotation of the output shaft of the electric motor, the gear reducer, etc., the wear powder of the gear, etc. Will also be protected.

According to a third aspect of the present invention, the wall portion in the second aspect forms a horseshoe-shaped space for accommodating the control circuit by the outer wall of the second case and the partition plate, and further comprises Since the output shaft and the gear reducer are configured to be disposed in a space formed inside the horseshoe-shaped space, in addition to the above-described operation of claim 1, particularly in a limited housing. In this space, the accommodation space for the control circuit can be widened.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a longitudinal sectional view showing the structure of a wheel motor according to the present embodiment. In FIG. 1, reference numeral 1 denotes a wheel motor, and the wheel motor 1 is a wheel 3 on which a tire (wheel) 2 is mounted. The motor 4 and the gear reducer 5 are built in a housing 6 arranged inside the
The wheel 3 is configured to be rotationally driven by the rotation output of.

The housing 6 has a substantially bowl-shaped outer case 6a.
The partition plate 6c is interposed between the inner case 6b and the inner case 6b.
The outer case 6a and the partition plate 6c are
As shown in FIG. The outer case 6a, the inner case 6b, and the partition plate 6c are
Cast by die casting.

A shaft insertion hole 6aa is provided at the center of the outer case 6a.
Are formed, and a partition wall portion 6ab for forming a horseshoe-shaped space S (see FIG. 3) is formed inside the outer case 6a (inside the housing 6). The inner case 6b is fixed to a vehicle body (not shown) by the bolts 12 shown in FIG.

The electric motor 4 includes a stator (stator) 7 housed in an inner case 6b, a rotor (rotor) 8 rotatably provided inside the stator 7, and a rotor 8
And an output shaft 9 for transmitting the rotation output of the wheel 3 to the wheel 3 via the gear reducer 5.

As shown in FIG. 2, the stator 7 has a large number of magnetic thin plates formed by integrally projecting a large number of magnetic pole projections on the inner peripheral edge of the annular portion at equal intervals in the circumferential direction. A three-phase field coil 7d is wound around each magnetic pole 7b of a stator main body 7a formed by laminating through a coil bobbin 7c, so that a rotating magnetic field is generated by the field coil 7d. It is configured. A plurality of outer peripheral portions of the stator 7 are fixed to the partition plate 6c by bolts 13.

The rotor 8 is provided at equal intervals in the circumferential direction on the outer periphery of a rotor body 8b having a shaft insertion hole (rotation center hole, hollow portion) 8a as a rotation center hole over the entire axial length. A plurality of magnets 8c. The axial length of the inner peripheral portion of the rotor main body 8b is longer than the axial length of the outer peripheral portion, and teeth forming the first gear 5a of the gear reducer 5 are formed in that portion. The outer peripheral portion of the rotor main body 8b having a short axial length is
The output shaft 9 is centered via bearings 14a and 14b such as ball bearings which are rotatably opposed to the inner peripheral portion of the stator 7 and are press-fitted at both ends of the inner peripheral portion of the rotor main body 8b having a short axial length. It is configured to rotate.

The output shaft 9 has a mounting flange 15 integrally formed at one end thereof fixed to a hub 3a of the wheel 3 via bolts 16 and nuts 17. Output shaft 9
Is rotatably supported in a shaft insertion hole 6aa of the outer case 6a via a bearing 18 such as a ball bearing, and the other end is rotatably supported in a central recess of the inner case 6b via a bearing 19 such as a ball bearing. I have. The output shaft 9
Are inserted (penetrated) in the shaft insertion hole 8a of the rotor 8 in a non-contact state. Further, the electric motor 4 having the stator 7 and the rotor 8 as main components is a flat electric motor having a short axial length, and the dimension of the wheel motor 1 as a whole in the direction of the output shaft 9 is short. Has become.

A plurality of gear reducers 5 (4 in this embodiment)
) Gears 5a, 5b, 5c and 5d. That is, the first gear 5a is integrally formed concentrically with the other end (the left end in FIG. 1) of the rotor 8 as described above. Second and third gears 5b,
5c is fixed to the same rotating shaft (support shaft) 20 and rotates integrally with each other, and the second gear 5b and the first gear 5
a mesh with each other. The support shaft 20 is located below the output shaft 9 and is eccentric to the output shaft 9. One end of the support shaft 20 is rotatably supported in a recess of the partition plate 6c via a bearing 21 such as a ball bearing, and the other end is rotatably supported in a recess of the outer case 6a via a bearing 22 such as a ball bearing. .

The fourth (last) gear 5d is fixed to the output shaft 9 and rotates integrally with the output shaft 9. The fourth gear 5d and the third gear 5c mesh with each other. Therefore, when the rotor 8 rotates by the action of the rotating magnetic field generated by the stator 7, the first gear 5 a integrally formed with the rotor 8 rotates at the same rotation speed as the rotor 8.
Then, the rotational output of the first gear 5a is reduced through the second and third gears 5b and 5c and transmitted to the fourth gear 5d, and the output shaft 9 and the wheel 3 are reduced in speed by the same speed as the fourth gear 5d. The rotor rotates in the same direction as the rotor 8 at the set rotation speed. For example, when the rotor 8 rotates forward at 750 rpm, the rotation output shaft 9 and the wheel 3 are reduced by the gear reducer 5 and rotate forward at 150 rpm.

At the center of the partition plate 6c, the rotor body 8b
Insertion hole 6 for inserting (penetrating) the axial length of the
cb is formed. The space S formed by the partition plate 6c and the horseshoe-shaped partition wall portion 6ab of the outer case 6a.
A first substrate 23 for forming a control circuit for driving the electric motor 4 is attached by screws 24 (see FIG. 3). Also, on the back surface of the partition plate 6c (the surface opposite to the surface on which the first substrate 23 is provided), a donut shaped drive circuit for supplying a drive current to the electric motor 4 driven by a signal from the control circuit is provided. Two substrates 25 are attached (see FIG. 4). The reason why the space for the control circuit is horseshoe-shaped is that the accommodation space for the control circuit is made as large as possible in the limited space in the housing 6.

Various circuit elements 23a constituting a control circuit for driving the electric motor 4 are provided on the horseshoe-shaped first substrate 23.
(IC, etc.) is attached, and the second substrate 25 has a donut shape.
Is mounted with a power transistor (power MOSFET) 25a for supplying a current to the field coil 7c, which will be described later. The partition plate 6c and the first substrate 23,
An insulating sheet film is interposed between the second substrate 25 and the second substrate 25.

The motor 4 is constituted by a brushless motor having a permanent magnet rotor 8 and a three-phase stator winding (field coil 7c), and has a position detector 26 for detecting the position of the rotor 8. doing. The position detecting unit 26 includes a ring-shaped magnet 26a embedded on the upper surface of the rotor 8 and magnetic poles attached at a predetermined angle (for example, 120 degrees) at positions on the second substrate 25 facing the ring-shaped magnet 26a. And a sensor 26b.

The magnetic pole sensor 26b can be a magnetic sensor such as a Hall element, and the position detector 26 can be constructed using various known means such as position detection by an optical sensor. It is possible.

Next, the procedure for assembling the wheel motor 1 will be described. When assembling the wheel motor 1, first,
The rotating shaft 9 is attached to the outer case 6a into which the seal member 27 and the bearings 18 and 22 are press-fitted. The reduction gears, that is, the second, third, and fourth gears 5 are provided on the outer case 6a.
b, 5c, 5d are attached.

Next, the first substrate 23, the second substrate 25, and the stator 7 are attached to the partition plate 6c, and wiring to the stator 7 is performed. Then, the partition plate 6c is fixed to the outer case 6a with bolts 11. Next, the rotor 8 into which the bearings 14b, 14b are press-fitted is inserted into the stator 7. Then, the inner case 6b into which the bearing 19 is press-fitted into the partition plate 6c is attached by the bolt 10.

According to this embodiment, the output shaft 9 of the motor 4
Is rotatably supported at both end portions of the housing 6 in a state where it passes through the rotation center hole of the fourth gear 5d, which is the final stage of the gear reducer 5, and the shaft insertion hole 8a of the rotor 8.
Although the electric motor 4 and the gear reducer 5 are disposed in the space inside the wheel 3, the configuration is simplified. Further, the outer case 6a, the components of the gear reducer 5, the partition plate 6c, the components of the electric motor 4, and the inner case 6b can be sequentially fitted and assembled on the basis of the output shaft 9, so that the assembly is facilitated. In addition, since the support span of the output shaft 9 can be maximized in spite of the short dimension of the wheel motor 1 in the direction of the output shaft 9 as a whole, sufficient support strength against the falling down of the wheel 3 including the tire 2 can be obtained. Becomes possible.

Since the control circuit for driving the electric motor 4 is provided in the space S of the housing 6 and separated by the horseshoe-shaped partition wall 6ab, the vehicle body on which the wheel motor 1 is mounted. This eliminates the need for space for mounting a control circuit on the frame side, protects the control circuit from rainwater, mud, etc., as well as lubricating oil and gear abrasion powder caused by rotation of the rotating shaft 9, the gear reducer 5, and the like. Etc., and also from the radiant heat from the electric motor 4. In addition, since the number of wires of the power system between the vehicle body frame and the wheel motor 1 can be reduced (if the motor 4 has three phases, the number of power lines can be two, and if the body ground, it can be one). The versatility of the motor 1 is improved by minimizing the restriction on the vehicle body to be mounted when mounting the motor 1 on the vehicle body and improving the vehicle mountability, or expanding the use of the motor 1 to other types of vehicles. It becomes possible. Further, the electric motor 4 is constituted by a brushless electric motor having the permanent magnet rotor 8, and the position detector 26 for detecting the position of the rotor 8 is provided on the rotor 8 side. 6c separates from the gear reducer 5 and is disposed close to the rotor 8, so that the sensor signal line between the control circuit and the sensor where noise easily travels is shortened while maintaining the environment of the position detecting section 26 in a favorable environment. be able to.

Further, since the rotor 8 is supported on the output shaft 9 via the bearings 14a and 14b, the diameter of the bearings 14a and 14b supporting the rotor 8 can be small, and the gear reducer 5 can be used.
Is reduced to two steps, the rotor 8 and the output shaft 9 rotate in the same direction, so that the bearings 14a and 14b
Since only a small relative rotation difference between the shaft and the output shaft 9 needs to be supported, the wear resistance is also improved.

The present invention is not limited to the above embodiment. For example, the horseshoe-shaped partition wall can be formed integrally with the partition plate 6c without being formed integrally with the outer case 6a. It is also possible to integrally form the horseshoe-shaped partition wall portions into the outer case 6a and the partition plate 6c in half.

[0033]

As described in detail above, according to the wheel motor of the present invention, the motor is constituted by a brushless motor having a magnet rotor, and the first motor which accommodates the motor in a space inside the wheel. A case, a second case housing the gear reducer, the first case and the second case.
A housing configured by a partition plate for partitioning between the case and the case, a mounting portion for a stator of the motor, and a sensor for detecting a position of the magnet rotor are mounted on a motor housing side of the partition plate. Part, on the gear reduction gear housing side of the partition plate, a support portion for supporting a rotation shaft of a gear of a predetermined stage of the gear reduction gear eccentrically arranged with respect to an output shaft of the electric motor is formed, and an output shaft of the electric motor is formed. Is configured to be supported by the first case accommodating the electric motor and the second case accommodating the gear reducer while penetrating the partition plate, so that the configuration is simple and easy to assemble. In addition, the environment of the sensor for detecting the position of the magnet rotor can be kept good, and the support span of the output shaft can be made long, so that it is possible to obtain high support strength against the fall of the tire.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a wheel motor according to one embodiment of the present invention.

FIG. 2 is a sectional view of a motor housing portion in FIG.

FIG. 3 is a cross-sectional view of a first substrate housing portion in FIG.

FIG. 4 is a sectional view of a second substrate housing portion in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Wheel motor 3 ... Wheel 4 ... Electric motor 5 ... Gear reducer 5a ... 1st gear 5b ... 2nd gear 5c ... 3rd gear 5d ... 4th gear (final stage gear) 6 ... Housing 6a ... Outer case 6ab ... Partition Wall part 6b ... Inner case 6c ... Partition plate 7 ... Stator 8 ... Rotor 8a ... Shaft insertion hole (rotation center hole) 9 ... Output shaft 20 ... Support shaft 23 ... First board 25 ... Second board 26 ... Position detection Part 26a: Ring-shaped magnet 26b: Magnetic pole sensor S: Space

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshihiro Iijima 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Technical Research Institute Co., Ltd. (56) References JP-A-7-96753 (JP, A) JP-A Heihei 7-81436 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60K 7/00

Claims (3)

(57) [Claims] 1. A wheel motor comprising: an electric motor and a gear reducer arranged in a space inside a wheel, wherein the wheel is rotationally driven by a rotation output of the electric motor reduced by the gear reducer. The motor is constituted by a brushless motor having a magnet rotor, and a first case accommodating the motor in a space inside a wheel, a second case accommodating the gear reducer, a first case and a second case. A housing configured by a partition plate that separates the case from the second case, a motor-mounting side of the partition plate includes a stator mounting portion for the motor, and a sensor for detecting a position of the magnet rotor. Attachment portion, on the gear reducer housing side of the partition plate, forming a support portion that supports the rotation shaft of a gear of a predetermined stage of the gear reducer that is eccentrically arranged with the output shaft of the electric motor, The output shaft of the electric motor, in a state penetrating the partition plate,
A wheel motor configured to be supported by a first case accommodating the electric motor and a second case accommodating the gear reducer, respectively. 2. A wall for forming a separated space where the gear reducer is not disposed between a second case accommodating the gear reducer and the partition plate. 2. The wheel motor according to claim 1, wherein the wheel motor is formed integrally with at least one of the partition plates and accommodates a control circuit for driving the electric motor in the space. 3. The wall portion forms a horseshoe-shaped space for accommodating the control circuit by the outer wall of the second case and the partition plate, and the output shaft of the electric motor and the gear reducer are formed in the horseshoe shape. 3. It is configured to be disposed in a space portion formed inside the space of (2).
The described wheel motor.