JPH0899538A - Vehicular wheel motor - Google Patents

Abstract

PURPOSE: To provide a vehicular wheel motor that can facilitate the manual push-pull of a vehicle with simple structure and suppress the generation of noise at the time of extremely low speed immediately after start, immediately before stop, and the like. CONSTITUTION: In a vehicular wheel motor 1, the reduction gear ratio of a reduction gear 5 is set to 1/10 or less, the stator 70 of an electric motor 4 is constituted of a closed slotted iron core, and the ratio between the number of magnetic poles 8c of the rotor 8 of the electric motor 4 and the number of slots of the stator 70 is set to be non-integer times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel motor for a vehicle, which is used as a drive source for an industrial vehicle such as a cargo handling vehicle and which is constructed by integrally mounting an electric motor with a speed reducer on a wheel of the industrial vehicle.

[0002]

2. Description of the Related Art A wheel motor for a vehicle used as a drive source for an industrial vehicle such as a cargo handling vehicle has a planetary gear reducer built-in, or the rotary output of a rotary electric motor is passed through the gear reducer. And the like, which are transmitted to wheels (Japanese Patent Publication No. 59-26486).

The above-mentioned vehicle wheel motors are usually
In order to make the electric motor small and large in output, it is necessary to make the rotational speed relatively high and the output rotational speed relatively low,
The speed reduction ratio of the speed reducer is set to 1/20 or more. For example, the rotation speed of the electric motor is 3000 rpm, and the speed reduction ratio of the speed reducer is set so that the output rotation speed transmitted to the wheels is about 150 rpm. There is.

[0004]

However, in each of the above-described conventional vehicle wheel motors, the number of gears used is large and the meshing rotation speed of each gear is high. Therefore, when a battery rises or a motor failure occurs, The traction force required to push and pull the vehicle is so large that it is difficult to push and pull the vehicle manually.

In order to facilitate pushing and pulling of the vehicle by such human power, a vehicle wheel motor having means for releasing the meshing of a part of the gears constituting the speed reducer from the outside has been proposed if necessary. It is (actual exploitation Sho 62-1610
No. 26), the structure is very complicated by providing a means for releasing the meshing of a part of the gears constituting the speed reducer.

On the other hand, when the reduction gear ratio of the reduction gear is set to 1/10 or less, the battery rises or the motor fails even if there is no means for releasing the meshing of a part of the gears forming the reduction gear. Pushing and pulling the vehicle by human power at the time of occurrence becomes relatively easy, and the structure is simplified, but since it is necessary to make the output speed relatively low as described above,
By setting the reduction ratio of the speed reducer to 1/10 or less, it is necessary to significantly reduce the rotation speed of the electric motor.

However, if the rotation speed of the electric motor is significantly reduced, a large reaction load received from a wheel under a large load such as vehicle weight and a low torque of the electric motor at a very low speed immediately after starting or immediately before stopping. It has been found that a tapping sound of each gear of the speed reducer is generated due to the relationship with the torque pulsation, that is, cogging, and the tapping sound becomes a noise that makes a person uncomfortable.

An object of the present invention is to provide a vehicle having a simple structure that can easily push and pull the vehicle by human power and can suppress the generation of noise at extremely low speed immediately after starting and immediately before stopping. To provide a wheel motor.

[0009]

According to the first aspect of the present invention,
In a vehicle wheel motor configured by integrally mounting an electric motor with a speed reducer on wheels, a reduction ratio of the speed reducer is set to 1/10 or less, and a stator of the electric motor is configured by a closed slot iron core, The ratio between the number of magnetic poles of the rotor of the electric motor and the number of slots of the stator is set to be a non-integer multiple.

According to a second aspect of the present invention, in the vehicle wheel motor according to the first aspect, the closed slot iron core constituting the stator has a ring-shaped connecting portion on the inner peripheral surface of which the rotor is arranged to face each other. Magnetic pole portion core formed with a plurality of magnetic pole teeth radially extending outward from each other, and a yoke portion arranged so as to surround the magnetic pole portion iron core outside and a plurality of grooves formed in an inner peripheral portion. An iron core, each of the magnetic pole teeth is fitted into a corresponding groove, and the connecting portion is formed such that the width dimension in the radial direction gradually decreases toward the central portion between the magnetic pole teeth. Is characterized by.

According to a third aspect of the present invention, in the vehicle wheel motor according to the second aspect, the minimum radial width of the connecting portion is 1% to 3% of the inner diameter of the connecting portion.
It is characterized in that the size is set within the range up to%.

[0012]

In the vehicle wheel motor according to the first aspect of the present invention, the reduction ratio of the reduction gear is set to 1/10 or less, the stator of the electric motor is constituted by the closed slot iron core, and the number of magnetic poles of the rotor of the electric motor is fixed. Since the ratio to the number of slots of the child is set to be a non-integer multiple, the traction force required to push and pull the vehicle is reduced to a size where the vehicle can be easily pushed and pulled manually, and the magnetic flux due to the number of magnetic poles is reduced. And cogging caused by abrupt fluctuations of magnetic flux between each slot are suppressed, and a large reaction load and electric motor from a wheel that receives a large load such as vehicle weight at very low speed immediately after starting or just before stopping The hitting sound of the gear caused by the relationship with the cogging is suppressed.

According to another aspect of the wheel motor for a vehicle of the present invention, the closed slot iron cores that constitute the stator extend radially outward from the ring-shaped connecting portions where the rotor faces the inner peripheral surface. It has a magnetic pole portion core formed with a plurality of magnetic pole teeth, and a yoke portion core arranged so as to surround the outside of the magnetic pole portion core and having a plurality of grooves formed in the inner peripheral portion, each magnetic pole tooth corresponding Since the connecting portion is formed so that the width in the radial direction becomes gradually smaller toward the central portion between the magnetic pole teeth, the occurrence of cogging of the electric motor at extremely low speed is suppressed. A decrease in the efficiency of the electric motor due to an increase in the self-resonance of the stator is suppressed.

In the wheel motor for a vehicle according to the third aspect of the invention, the minimum radial width dimension of the connecting portion is set within the range of 1% to 3% of the inner diameter dimension of the connecting portion. While suppressing the efficiency decrease due to the increase, it is possible to secure sufficient strength in the connecting portion when the magnetic pole portion core is formed by press molding or the like.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the construction of an embodiment of a vehicle wheel motor of the present invention, and FIG. 2 is a view showing the construction of a stator and a rotor of an electric motor of the vehicle wheel motor of FIG. 1, respectively. Is.

As shown in FIG. 1, a vehicle wheel motor 1 used as a drive source for an industrial vehicle includes a housing 60 arranged inside a wheel 3 having tires (wheels) 2 mounted therein. Includes a motor 4 and a gear reducer 5. 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
The partition plate 63 is interposed between the inner case 1 and the inner case 62. The inner case 62 and the partition plate 63 are bolts 10
The outer case 61 and the partition plate 63 are fastened together by bolts (not shown). Outer case 6
1, the inner case 62 and the partition plate 63 are cast by aluminum die casting.

A shaft insertion hole 61a is formed in the center of the outer case 61.
And a partition wall portion 61b for forming a horseshoe-shaped space S inside the outer case 61 (inside the housing 60).

The inner case 62 is fixed to the vehicle body side (not shown) with bolts (not shown).

The electric motor 4 is housed in the inner case 62 and is composed of a closed slot iron core (stator).
70, a rotor (rotor) 8 rotatably provided inside the stator 70, and an output shaft 9 for transmitting the rotation output of the rotor 8 to the wheel 3 via the gear reducer 5. Have.

As shown in FIG. 2, the stator 70 includes a magnetic pole portion core 71 and a yoke portion core 72 arranged so as to surround the magnetic pole portion core 71 outside. The magnetic pole core 71 is
A ring-shaped connecting portion 7 in which the rotor 8 is arranged so as to face the inner peripheral surface.
A plurality of magnetic pole teeth 7 extending radially from 1a toward the outside
It is configured by laminating a large number of magnetic thin plates on which the projections for forming 1b are formed. The magnetic pole teeth 71b are arranged at equal intervals in the circumferential direction of the connecting portion 71a. In addition,
In this embodiment, the number of magnetic pole teeth 71b is set to 12, and the number of closed slots formed by the connecting portions 71a between the magnetic pole teeth 71b is 12.

The connecting portion 71a is tapered on the outer peripheral side so that the radial width dimension gradually decreases toward the central portion between the magnetic pole teeth 71b, and the radial width dimension 1 at the central portion is the connecting portion 7e. It is set to 2% of the inner diameter dimension L. In this embodiment, 1 is set to 2% with respect to L, but the radial width dimension 1 in the central portion is set within the range of 1% to 3% with respect to the inner diameter dimension L of the connecting portion 71a. It suffices to set it so that it fits, and thereby, when punching the magnetic thin plates one by one, sufficient strength of the minimum radius width dimension portion can be secured. Further, the inclination angle θ toward the central portion between the magnetic pole teeth 71b is set to 60 degrees with respect to the straight line passing from the center of the stator 70 to the central portion (minimum width dimension portion).

A three-phase field coil 74 is wound around each magnetic pole tooth 71b via a coil bobbin 73, and the field coil 7b
A rotating magnetic field is generated by 4.

The yoke core 72 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 of the inner peripheral portion forms a fitting groove 72b, and the tip of the magnetic pole tooth 71b of the corresponding magnetic pole portion iron core 71 is fitted in each fitting groove 72b. In addition,
In this embodiment, the number of fitting grooves 72b is twelve.

The stator 7 is attached to the outer periphery of the yoke core 72.
A bolt insertion hole 72a for receiving the bolt 13 for fixing 0 to the partition plate 63 is provided.

As shown in FIG. 1, the rotor 8 has a shaft insertion hole (rotation center hole, which is a rotation center hole) over the entire axial length thereof.
It includes a rotor body 8b provided with a hollow portion) 8a.
As shown in FIG. 2, a plurality of skew magnetized magnets 8c arranged at equal intervals in the circumferential direction are mounted on the outer peripheral portion of the rotor body 8b. In this example,
The skew angle of the skew magnetized magnets 8c is 10 degrees, and the number of skew magnetized magnets 8c is 8 so that the ratio of the number of skew magnetized magnets 8c to the number of closed slots is a non-integer multiple.

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. Rotor body 8
An outer peripheral portion of b having a short axial length is rotatably opposed to an inner peripheral portion of the stator 70, and bearings 14a such as ball bearings press-fitted to both ends of the inner peripheral portion of the rotor main body 8b having a short axial length,
It is configured to rotate around the output shaft 9 via 14b.

A mounting flange 15 is integrally formed at one end of the output shaft 9, and the mounting flange 15 is fixed to the hub 3a of the wheel 3 with bolts 16 and nuts 17. One end of the output shaft 9 has a shaft insertion hole 61 of the outer case 61.
A bearing 18 such as a ball bearing is rotatably supported at a, and the other end is rotatably supported in a central recess of the inner case 62 through a bearing 19 such as a ball bearing.
The output shaft 9 is inserted (penetrated) in the shaft insertion hole 8a of the rotor 8 in a non-contact state.

The electric motor 4 whose main constituent elements are the stator 70 and the rotor 8 is a flat brushless 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. Is configured to be.
The output rotation speed of the electric motor 4 is 750 rpm.

A plurality of gear speed reducers 5 (four gears in this embodiment) are used.
(2 pieces) 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 support shaft 20 is arranged eccentrically with the output shaft 9 and below the output shaft 9. One end of the support shaft 20 is rotatably supported in a recess of the partition plate 63 via a bearing 21 such as a ball bearing, and the other end is rotatably supported in a recess of the outer case 61 via a bearing 22 such as a ball bearing. .

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 generated by the stator 70, 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 the second and third gears 5b, 5
After being decelerated by c, it is transmitted to the fourth gear 5d, and as the fourth gear 5d decelerates and rotates, the output shaft 9 and the wheel 3 move to the fourth gear.
It rotates in the same direction as the rotor 8 at the same speed as the gear 5d.

For example, when the rotor 8 normally rotates at 750 rpm, the rotation output shaft 9 and the wheel 3 are connected to each other by the gear reducer 5
The speed is reduced by 150 rpm and the positive rotation is performed at 150 rpm, and the speed reduction ratio is 1/5.

At the center of the partition plate 63, the rotor body 8b is provided.
Insertion hole 6 for inserting (penetrating) the axial length of the non-contact state
3b is formed. In a space S formed by the partition plate 63 and the horseshoe-shaped partition wall portion 61b of the outer case 61, a first control circuit for driving the electric motor 4 is formed.
The board 23 is attached by screws (not shown). Further, on the back surface of the partition plate 63 (the surface opposite to the surface on which the first substrate 23 is arranged), a doughnut-shaped first drive circuit for driving a electric current to the electric motor 4 driven by a signal from the control circuit. Two substrates 25 are attached. In this way, by making the space for the control circuit into a horseshoe shape, it becomes possible to take the accommodation space for the control circuit as wide as possible in the limited space inside the housing 60.

Various circuit elements (not shown) constituting a control circuit for driving the electric motor 4 are attached to the horseshoe-shaped first substrate 23, and a field coil is attached to the donut-shaped second substrate 25. A power transistor (power MOSFET) 25a for supplying a current to 73 is attached. An insulating sheet film (not shown) is interposed between the partition plate 63 and the first substrate 23 and the second substrate 25.

The position of the rotor 8 of the electric motor 4 is determined by the position detector 2
Detected at 6. The position detection unit 26 includes a ring-shaped magnet 26a embedded in the upper surface of the rotor 8 and magnetic poles attached at a predetermined angle (for example, 120 degrees) at a position on the second substrate 25 facing the ring-shaped magnet 26a. It is composed of a sensor 26b.

A magnetic sensor such as a Hall element can be used as the magnetic pole sensor 26b, and the position detecting section 26 can be composed of various known means such as position detection by an optical sensor. is there.

As described above, the reduction ratio of the speed reducer 5 is 1 /
Since it is set to 10 or less, the number of gears to be used is small and the meshing rotation speeds of the gears 5a, 5b, 5c, 5d are low, and the structure is simple, and when the battery rises or the motor malfunctions, The traction force required for pushing and pulling the vehicle is reduced to a size at which the vehicle can be pushed and pulled easily by human power, and the push and pull of the vehicle by human power can be facilitated with a simple structure.

Further, the stator 70 of the electric motor 4 is formed of a closed slot iron core, and the ratio of the number of magnetic poles (8) of the rotor 8 of the electric motor 4 to the number of slots (12) of the stator 70 is a non-integer multiple. Therefore, the gears 5a, 5b, 5 depending on the relationship between the large reaction load received from the wheel 2 and the cogging of the electric motor 4 at a very low speed such as immediately after starting and immediately before stopping.
The generation of tapping sounds c and 5d is suppressed, and it is possible to suppress the generation of noise at extremely low speed immediately after starting and immediately before stopping.

Further, as in the present embodiment, by mounting the skew magnetizing magnet 8c on the rotor 8, it is possible to more reliably suppress the occurrence of torque pulsation at low torque of the electric motor 4 at extremely low speed, that is, cogging. be able to.

Further, since the stator 4 is formed of a closed slot iron core and the connecting portion 71a is formed so that the width in the radial direction becomes gradually smaller toward the central portion between the magnetic pole teeth 71b, it becomes possible to operate at extremely low speed. While suppressing the occurrence of cogging of the electric motor 4 in Fig. 4, the decrease in the efficiency of the electric motor 4 due to the increase in the self-resonance inductance is suppressed.

Furthermore, since the minimum outer diameter direction width l of the connecting portion 71a is set to 2% of the inner diameter dimension L of the connecting portion 71a, press forming or the like can be performed while suppressing a decrease in efficiency due to an increase in self-inductance. Thus, when forming the magnetic pole portion iron core 71, it is possible to secure sufficient strength of the portion of the connecting portion 71a having the minimum outer diameter direction width dimension. The minimum radial dimension l in the connecting portion 71a
Is within the range of 1% to 3% of the inner diameter L of the connecting portion 71a, the same effect can be obtained.

In this embodiment, the skew magnetized magnet 8c is attached to the rotor 8, but instead of this,
The same effect can be obtained by mounting a sine wave magnetizing magnet.

In this embodiment, the number of skew magnetized magnets 8c is 8 and the number of closed slots is 12 so that the ratio of the number of skew magnetized magnets 8c to the number of closed slots is a non-integer multiple. However, the number of skew magnetized magnets 8c and the number of closed slots are not limited to this.

[0046]

As described above, according to the vehicle wheel motor of the first aspect, the reduction ratio of the speed reducer is reduced to 1 /.
Since it is set to 10 or less, the stator of the electric motor is configured by a closed slot iron core, and the ratio of the number of magnetic poles of the rotor of the electric motor to the number of slots of the stator is set to a non-integer multiple,
The traction force required to push and pull the vehicle is reduced to a level where the vehicle can be pushed and pulled easily by human power, and fluctuations in magnetic flux due to the number of magnetic poles and cogging caused by rapid fluctuations in magnetic flux between slots are suppressed. Then, at the very low speed such as immediately after starting and immediately before stopping, the hammering noise of the gear generated due to the relationship between the large reaction load received from the wheel that is heavily loaded such as the vehicle weight and the cogging of the electric motor is suppressed,
With a simple structure, it is possible to easily push and pull the vehicle by human power, and it is possible to suppress the generation of noise at extremely low speed immediately after starting and immediately before stopping.

According to the vehicle wheel motor of the second aspect, the closed slot iron core forming the stator is radiated outward from the ring-shaped connecting portion in which the rotor is opposed to the inner peripheral surface. The magnetic pole portion iron core formed with a plurality of magnetic pole teeth each extending, and arranged so as to surround the outside of the magnetic pole portion iron core,
Having a yoke portion core having a plurality of grooves formed in the inner peripheral portion,
Since each magnetic pole tooth is fitted into the corresponding groove and the connecting portion is formed so that the width in the radial direction becomes gradually smaller toward the central portion between the magnetic pole teeth, the cogging of the electric motor at extremely low speed can be prevented. It is possible to suppress the decrease in the efficiency of the electric motor due to the increase in the freewheeling inductance of the stator while suppressing the occurrence.

According to the vehicle wheel motor of the third aspect, the minimum radial width dimension of the connecting portion is set within the range of 1% to 3% of the inner diameter dimension of the connecting portion. While suppressing the efficiency decrease due to the increase of the inductance, it is possible to secure sufficient strength at the connecting portion when the magnetic pole core is formed by press molding or the like.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of an embodiment of a vehicle wheel motor of the present invention.

FIG. 2 is a diagram showing configurations of a stator and a rotor of an electric motor of the vehicle wheel motor shown 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) 8 ... Rotor 8c ... Skew magnetizing magnet 60 ... Housing 70 ... Stator 71 ... Magnetic pole part core 71a ... Connecting part 71b ... Magnetic pole teeth 72 ... Yoke part core 72b ... Fitting groove

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Iijima 1-4-1 Chuo, Wako, Saitama Stock Company Honda R & D Co., Ltd.

Claims (3)

[Claims] 1. A wheel motor for a vehicle, which is configured by integrally mounting a motor with a speed reducer on wheels, wherein a reduction ratio of the speed reducer is set to 1/10 or less, and a stator of the motor is a closed slot iron core. And a ratio of the number of magnetic poles of the rotor of the electric motor to the number of slots of the stator is set to be a non-integer multiple. 2. The closed slot iron core forming the stator has a plurality of magnetic pole teeth radially extending outward from an inner peripheral surface of a ring-shaped connecting portion facing the rotor. A magnetic pole part core and a yoke part core which is arranged so as to surround the magnetic pole part core outside and has a plurality of grooves formed in the inner peripheral part, and each magnetic pole tooth is fitted in a corresponding groove. 2. The vehicle wheel motor according to claim 1, wherein the connecting portions are formed such that the width dimension in the radial direction gradually decreases toward the central portion between the magnetic pole teeth. 3. The vehicle according to claim 2, wherein the minimum radial dimension of the connecting portion is set to a dimension within a range of 1% to 3% of an inner diameter dimension of the connecting portion. Wheel motor.