JPH11308708A - Electric vehicle and its driving motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric vehicle and its driving motor from which a differential gear can be eliminated, and which enable the weight reduction and the cost reduction while a single motor is used. SOLUTION: A driving motor 20 consists of a DC brushless motor which is composed of a single stator 22 and two rotors 23 and 24 arranged on a common axis. The rotary shafts 25 and 30 of the respective rotors 23 and 24 are linked with left and right driving wheels 11 through planetary gear mechanisms 26 and 31 and universal joints 29 and 34 respectively and, further, linked with each other with a clutch mechanism having retaining balls. A current applied to the armature coil of the stator 22 is controlled in accordance with the rotation position of one rotor 23. When a difference in the number of rotation is produced between the rotary shafts 25 and 39, the clutch mechanism slips.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle in which the structure of a power motor is improved and a power motor thereof.

[0002]

2. Description of the Related Art Conventional electric vehicle drive systems include a drive system that distributes rotational force from a single power motor to left and right drive wheels via a differential gear that absorbs the rotational speed difference between the left and right wheels, There are two types, one in which a motor is provided for each of the drive wheels and both left and right wheels are driven at a required number of revolutions.

[0003]

The former has a drawback that it requires a relatively large differential gear, which increases the weight and cost. Further, the latter has a disadvantage that the weight and the cost also increase because two sets of the motor and its controller are required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electric vehicle which can eliminate a differential gear while using a single motor and can reduce the weight and cost, and a motor for driving the electric vehicle.

[0005]

According to a first aspect of the present invention, there is provided a power motor mounted on a body of an electric vehicle for driving left and right driving wheels, and a single stator provided in a motor case. And two rotors that are rotatably provided independently of each other with respect to the stator and are connected to the right and left driving wheels.

A power motor according to a second aspect of the present invention is characterized in that, in the above-mentioned motor, the rotating shafts of both rotors are connected via a clutch mechanism which is disengaged and slips with a predetermined torque or more.

According to a third aspect of the present invention, there is provided an electric vehicle including a power motor for driving left and right driving wheels on a vehicle body, wherein the power motor is provided in a single stator provided in a motor case; And two rotors that are rotatably provided independently of each other and connected to the right and left drive wheels.

[0008]

According to the first and third aspects of the present invention, since the stator is single, the weight can be reduced as compared with the case where two independent motors are provided. Since an independent rotor is provided for each drive wheel, no differential gear is required, which also contributes to weight reduction.

According to the second aspect of the present invention, when the vehicle is traveling straight, the left and right drive wheels rotate at the same speed, so that no torque acts between the rotating shafts of the two rotors and the clutch mechanism Is in a connected state, and both rotors rotate synchronously. When a difference in the number of rotations of the drive wheels occurs due to the turning of the vehicle, a torque is generated between the rotation shafts of the two rotors connected to these wheels, and when the torque exceeds a predetermined value, the clutch mechanism is disengaged. It is possible to rotate with a free rotational speed difference. Therefore, in most cases, both rotors rotate synchronously and rotate with high efficiency, and only when the vehicle turns, the clutch mechanism slips and stable turning is possible.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 10 is an electric vehicle body,
Reference numeral 11 denotes left and right driving wheels, and the driving shaft 1 of each driving wheel 11
1A is connected to a shock absorber 13 via a bearing 12, and is supported by the vehicle body 10 via this. A power motor 20 is fixed to the vehicle body 10 at the center of each of the left and right drive wheels 11.

The power motor 20 is constituted by, for example, a DC brushless motor, and its specific structure is as follows. A single stator 22 is disposed in the motor case 21, which has a well-known structure in which an armature winding is wound around a stator core, not shown in detail. A rotor housing space having a columnar shape is formed on the inner peripheral side of the stator 22, and two rotors 23 and 24 are coaxially arranged side by side here. Each of the rotors 23, 24 is set to have a size occupying about half of the rotor accommodating space, and has field portions 23A, 24A on the outer peripheral portions, respectively (see FIG. 2).

The rotating shaft 25 of one rotor 23 has an end opposite to the other rotor 24 protruding to the side of the stator 22 and is directly connected to a sun gear 26A of a planetary gear mechanism 26. The planetary gear mechanism 26 is, for example, a ring gear 2.
6C is a planetary type in which the output shaft 27 is connected to a planetary gear 26B.
9 is connected to one drive shaft 11A. Further, the rotation shaft 30 of the other rotor 24 has an end opposite to the one rotor 23 protruding to the side of the stator 22 and is directly connected to a sun gear 31A of another set of planetary gear mechanisms 31. The output shaft 32 connected to the planetary gear 31B of the planetary gear mechanism 31 penetrates through a bearing 33 provided on the motor case 21 and protrudes outside the motor case 21. The other drive shaft 11A also via a universal joint 34. It is connected to.

On the other hand, as shown in FIG. 3, a small diameter connecting shaft portion 25A protruding toward the opposite rotor 24 is provided at an end of the rotating shaft 25 of the rotor 23 in the motor case 21.
Are fitted to the outer periphery of the accommodating recess 30A formed at the end of the rotating shaft 30 of the counterpart rotor 24 with a predetermined gap left therebetween, and are rotatable via a bearing 30B.

A ball housing hole 35 is formed in the connecting shaft portion 25A from the outer peripheral surface toward the center axis direction.
A steel engagement ball 36 is always accommodated therein by being urged in a protruding direction by a compression coil spring 37. An engagement hole 38 with which the engagement ball 36 is engaged is formed on the inner peripheral wall of the housing recess 30A of the counterpart rotating shaft 30, and when the engagement ball 36 is engaged with the engagement hole 38. The two rotating shafts 25 and 30 rotate integrally with each other. When a rotation difference occurs between the rotating shafts 25 and 30, a torque is generated between the rotating shafts 25 and 30, and when the torque reaches a predetermined value or more, the engaging ball 3
6, the compression coil spring 37 is compressed and pushed back into the ball receiving hole 35, so that the connection between the rotating shafts 25 and 30 is released. Therefore, the engagement ball 36 and its related structure are separated. The clutch mechanism is configured to be disengaged and slip with a predetermined torque or more.

Although not shown, a well-known position detecting means such as a Hall element for detecting the rotational position of one of the rotors 23 is provided on the stator 22 side. The stator 22
Required armature coils are energized and the rotors 23, 24
The control device 39 and the power supply battery 40 for this purpose are installed at predetermined positions of the vehicle body 10.

This embodiment has the above configuration, and its operation will now be described. The electric vehicle runs using the power motor 20 as a drive source, and the power motor 20 is driven by detecting the rotational position of the rotor 23 and sequentially energizing the armature coils. When the electric vehicle travels straight, the left and right drive wheels 11 only need to be driven at the same rotational speed. However, both rotors 23 and 24 rotate synchronously. At this time, the engagement balls 36 of the clutch mechanism are engaged with the engagement holes 38, and the rotating shafts 25, 30 of the rotors 23, 24 are connected by the clutch mechanism.
4 reliably rotates synchronously and the motor efficiency does not decrease.

On the other hand, during cornering of the electric vehicle, the outer drive wheels 11 rotate at a higher rotational speed than the inner drive wheels. Then, a rotational speed difference is generated between the rotating shafts 25, 30 of the rotors 23, 24, so that a torque is generated between the shafts 25, 30. Is pushed back into the ball receiving hole 35 against the pressure. That is, since the clutch mechanism is in a state in which the connection between the two rotating shafts 25 and 30 is released, the two rotating shafts 25 and 26 rotate freely without being restrained from each other. Therefore, even if only a single stator 22 is provided, there is no influence from the rotational difference between the left and right wheels generated at the time of cornering of the electric vehicle.

As described above, the power motor 20 of the present embodiment comprises a single stator 22 and two rotors 23,2.
4, the left and right drive wheels 11 can be efficiently driven, so that the size and weight of the vehicle can be reduced as compared with a vehicle including two power motors and a control device therefor. Also, 1
Compared to a system in which both wheels are driven via a differential gear by a power motor of a stand, the weight of the differential gear is increased, so that the weight can be reduced.

In this embodiment, since the two rotors 23 and 24 are connected via the clutch mechanism, when the rotors rotate at the same speed, the clutch mechanism is in the connected state and both rotors 23 and 24 are connected. Rotate synchronously,
The efficiency as a DC brushless motor is not reduced. In addition, when a difference between the rotation speeds and a torque equal to or greater than a predetermined value is generated, the connection between the two rotation shafts 25 and 30 is released so that a slip occurs, so that the vehicle can turn stably.

In the present invention, since the power motor 20 is configured as a DC brushless motor, it is preferable to provide the above-described clutch mechanism. However, when this is configured by an induction motor, a rotating armature type DC brush motor, or the like. In this case, since the necessary slippage occurs naturally between the two, it is not necessary to provide a clutch mechanism.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the power motor.

FIG. 3 is an enlarged sectional view of the clutch mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Body 11 ... Drive wheel 20 ... Power motor 21 ... Motor case 22 ... Stator 23, 24 ... Rotor 26, 31 ... Planetary gear mechanism 36 ... Engagement ball 37 ... Compression coil spring 38 ... Engagement hole

Claims (3)

[Claims] An electric vehicle is mounted on a vehicle body to drive left and right driving wheels. A single stator provided in a motor case is provided so as to be rotatable independently of each other with respect to the stator. A power motor for an electric vehicle, comprising two rotors connected to the right and left drive wheels. 2. The power motor according to claim 1, wherein the rotating shafts of the two rotors are connected via a clutch mechanism that is disengaged and slips with a predetermined torque or more. 3. A vehicle having a power motor for driving left and right drive wheels on a vehicle body, wherein the power motor is provided with a single stator provided in a motor case and rotating independently of the stator. An electric vehicle comprising two rotors, which are provided as possible and are connected to the right and left driving wheels.