JP2006320057A - Motor for electric car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor for an electric car which can get stable steerability and sufficient acceleration force by giving a steering wheel and a non-steering wheel the differences in motor mass and rating thereby distributing the acceleration force required as the whole of a vehicle in front and in the rear. <P>SOLUTION: The torque required to accelerate a vehicle is properly distributed to a front wheel being a steering wheel and a rear wheel being a non-steering wheel. That is, a motor for the front wheel is lightened, and specifications of suppressing the torque are applied, and a motor for the rear wheel is made heavier in mass, and a motor of specifications of large torque is applied. The motors in front and in the rear share the torque required as a vehicle properly at large. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric motor used for an electric vehicle, and more particularly to a direct drive type electric motor built in a wheel.

In an electric vehicle in which a conventional electric motor is built in a wheel part, the electric motor has the same mass for both front wheels and rear wheels, and has the same rating (for example, Table 1 and Table 1 of Non-Patent Document 1). See Table 2.)
In a conventional electric vehicle, when driving four wheels or all wheels, the electric motor has been manufactured with the same specifications from the viewpoint of productivity and cost, and therefore, the selection of the electric motor in consideration of the steering is not sufficient.

“Meiden Time Report, Vol. 278, 2001, No. 3, p. 12, 13” 2001 (Table 1, Table 2)

  In conventional electric vehicles, all wheels use electric motors with the same specifications, so there was a merit that mass production effects could be expected in terms of productivity and price, but in terms of steering, measures were not taken to lighten the steering wheels Therefore, there was some difficulty in steep steering.

  To improve steering performance, it is important to reduce the mass of the steered wheels. However, if the mass of the motor is reduced, it will be difficult to produce the required torque. Torque, that is, acceleration force will decrease.

Therefore, in a front-wheel steering vehicle, when the front-wheel motor is lightened and the torque is reduced, a means for compensating the torque necessary for the vehicle with the rear wheels is required to obtain a sufficient acceleration force.

  The present invention distributes the acceleration force required for the entire vehicle by providing a difference in the motor mass and rating of the steered wheel and the non-steered wheel, thereby obtaining stable steering performance and sufficient acceleration force. The purpose is to provide an electric motor.

  In order to achieve the above object, an electric motor for an electric vehicle according to the present invention is to appropriately distribute torque necessary for accelerating a vehicle to a front wheel that is a steering wheel and a rear wheel that is a non-steering wheel. In other words, a specification with a lighter front wheel motor and reduced torque is applied, and a motor with a higher torque and a larger torque is applied to the rear wheel motor. Appropriately share the torque required for the vehicle between the front and rear motors.

  In the electric motor of the present invention, the wheel diameters used in the front wheel motor and the rear wheel motor are the same. In this case, the outer diameter of the electric motor is the same for the front wheel and the rear wheel. Therefore, it is possible to reduce the front wheel motor by reducing the iron core length, and for the rear wheel, it is possible to make a motor with a large torque by increasing the iron core length. Accordingly, the rim width of the wheel is narrower for the front wheel and wider for the rear wheel, so that the electric motor can be mounted on the wheel portion.

  When the vehicle accelerates, its center of gravity moves to the rear of the vehicle, so even if a motor with a larger torque is used for the rear wheels, there is no risk of slipping of the rear wheel tires. Since the front wheels are steered, the lighter the mass, the better the steering stability and the ease of use.

  In general, if a tire or a wheel rotates, a gyro effect causes a force to block the steering angle when attempting to change the steering angle. The gyro effect increases as the outer diameter increases, the mass increases, and the rotational speed increases. However, the gyro effect is increased by attaching an electric motor to the wheel portion.

  Since the required acceleration force of the vehicle is determined at the time of vehicle design, the torque distribution of the front wheel and rear wheel motors is determined in consideration of the handling stability of the vehicle, the riding comfort, the installation space of the motor, etc. .

  As described above, the electric motor according to the present invention distributes the acceleration force necessary for the entire vehicle by providing a difference in the motor mass and the rating of the steered wheel and the non-steered wheel, thereby stabilizing the steering and sufficient acceleration. Provided is an electric vehicle electric motor capable of obtaining power.

  As described above, by applying the present invention, it is possible to provide an electric vehicle electric motor that can sufficiently obtain an acceleration force as a vehicle and is excellent in steering performance. Furthermore, the motor torque distribution matches the weight distribution during acceleration, and a rational electric vehicle motor can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, preferred embodiments of an electric motor for an electric vehicle according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing a state in which the first embodiment is mounted on a front wheel that is steered and a rear wheel that is not steered by the electric motor according to the present invention in the first embodiment.
In FIG. 1, the upper half shows a state where it is attached to the front wheel, and the lower half shows a state where it is attached to the rear wheel, and the tire and the wheel have the same dimensions in the front and rear.

  In the upper half of the front wheel in FIG. 1, the stator 1 is fixed to the stator housing 2, and is attached to the knuckle 5 together with the brake unit 7 and the brake shoe 8, and constitutes a fixed portion of the front wheel portion. The rotor 3 is fixed to the rotor housing 4 and is fixed to the wheel hub 6 together with the tire wheel 9.

  In the lower half of the rear wheel in FIG. 1, the stator 21 is fixed to the stator housing 22 and is attached to the rear wheel axle 25 together with the brake unit 27 and the brake shoe 28, and constitutes a fixed portion of the rear wheel portion. Yes. The rotor 23 is fixed to the rotor housing 24 and is fixed to the wheel hub 26 together with the tire wheel 9.

  If the outer diameter of the iron core is the same, the torque of the motor is proportional to the iron core length. Therefore, if the iron core length of the rear wheel motor is 1.5 times the iron core length of the front wheel motor, for example, Torque is 1.5 times that of the front wheel motor. Hereinafter, the case where the iron core length is 60 mm for the front wheel and 90 mm for the rear wheel will be described.

  An embodiment of the present invention will be described for a case where a torque of 2000 Nm is required as an electric motor from the acceleration force required by the vehicle.

  If the vehicle is a four-wheel drive and the core length is 60 mm and 400 Nm is obtained as a torque, a torque of 600 Nm is generated at 90 mm. If a 400 Nm electric motor is used for the front wheels and a 600 Nm electric motor is used for the rear wheels, a torque of 2000 Nm can be obtained for the vehicle as a whole, and the required acceleration can be obtained.

  On the other hand, when the same motor is used for both the front and the rear, the torque of one motor is 500 Nm, and the iron core length at that time is 75 mm. Therefore, if the present invention is applied, the front wheel motor can shorten the iron core length by 15 mm, which is lighter, and the gyro effect can be reduced accordingly. While the vehicle is accelerating, the center of gravity moves backward and the weight moves toward the rear wheels. For this reason, even if the rear wheel torque is increased in order to obtain a large acceleration force, it is reasonable not to cause the tire to slip.

  FIG. 2 shows the case of the second embodiment, in which the outer diameters of the tire and the wheel are the same in the front and rear, the tire width and the rim width of the rear wheel are widened, and the present invention is applied. Generally, since the front wheels are steered, there is little room in the wheel house (not shown), but the rear wheels are not steered, so it can be said that there is a dimensional room. In large buses and the like, the rear wheels are double tires, and if this is a super single tire, an electric motor with a width more than double that of the front wheels can be applied.

In the sectional view of the electric vehicle electric motor according to Embodiment 1 of the present invention, the upper half shows the front wheel and the lower half shows the rear wheel. In the sectional view of the electric vehicle electric motor according to Embodiment 2 of the present invention, the upper half shows the front wheel and the lower half shows the rear wheel.

Explanation of symbols

1 Stator (front wheel)
2 Stator housing (front wheel)
3 Rotor (front wheel)
4 Rotor housing (front wheel)
5 Knuckles (front wheels)
6 Wheel hub (front wheel)
7 Brake unit (front wheel)
8 Brake shoes (front wheels)
9 Tire wheel 21 Stator (rear wheel)
22 Stator housing (rear wheel)
23 Rotor (rear wheel)
24 Rotor housing (rear wheel)
25 Rear wheel axle 26 Wheel hub (rear wheel)
27 Brake unit (rear wheel)
28 Brake shoe (rear wheel)
29 tire wheel (super single tire)

Claims (4)

In an outer rotor type or inner rotor type direct drive motor that does not have a comet gear or other speed reducer or speed increaser mounted on a wheel portion of a four-wheel, six-wheel, or eight-wheel electric vehicle traveling on a road An electric motor for an electric vehicle, characterized in that the motor mass and the motor rating of the front wheel motor that performs steering and the rear wheel motor that does not perform steering have different specifications. 2. The electric motor for an electric vehicle according to claim 1, wherein the electric motor for a rear wheel that is not steered is heavier and has a higher rating than the front wheel motor that is steered. The electric motor for an electric vehicle according to claim 2, wherein the rear wheel that is not steered is applied wider than the front wheel that steers the rim width of the wheel. The electric motor for an electric vehicle according to claim 2 or 3, wherein the mass and the rating of the electric motor are applied in the opposite direction in an electric vehicle that steers the rear wheel without steering the front wheel.

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