JPH05300712A - Variable torque-constant type wheel motor - Google Patents

Abstract

PURPOSE:To make a torque constant variable, by moving in a sliding way a rotor magnetic substance provided on the outer periphery of a rotor according to the rotational speed of a wheel, and by varying the respective flux linkages generated by a stator and the rotor magnetic substance. CONSTITUTION:A variable torque-constant type motor 10 is provided in a wheel 12. A rotor main body 20 is fastened to the wheel 12 by bolts 16, 18 via a wheel flange 14. To the rotor main body 20, a rotor flange 40 is fastened, and a weight 46 is provided on the rotor flange 40 in a sliding way. Thus, when a current flows in a coil 38 and the rotor main body 20 is rotated, the wheel 12 is rotated, and a vehicle travels. At this time, the weight 46 is rotated as the rotor main body 20 is rotated, and it generates a centrifugal force. Thereby, a magnet base 28 is moved while opposing to the energizing force of a return spring 52, and it is stopped in the position wherein the centrifugal force is balanced with the energizing force of the return spring 52. Therefore, the positional relation between a magnetic substance and a stator 32 can be varied, and the motor 10 can be driven from a low rotational speed to a high rotational speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a motor incorporated in a wheel used in an electric vehicle, and more particularly to a structure for varying a torque constant.

[0002]

2. Description of the Related Art In recent years, electric vehicles have been actively developed due to their characteristics of quietness and absence of exhaust gas, and some of them have already been put into practical use, although their use is limited.

As a drive system for this electric vehicle, there is a system in which a motor is built in each wheel and driven. Compared with the method in which the output of a single motor is distributed to each wheel, this method is characterized in that parts and space of the transmission system can be omitted and the transmission loss can be eliminated.

However, it is necessary to design the motor portion to be lightweight and small in order to be built in the wheel, to reduce the unsprung load, and to obtain good handling characteristics. Therefore, a permanent magnet type motor is often used as the motor type for this wheel motor. Also,
Since a motor of this type does not require an exciting current, there is no copper loss generated in the exciting coil, and therefore the efficiency is good. However, since the magnetic flux generated by the permanent magnet is always constant, the motor covers from low-speed rotation that requires a large torque (during low-speed traveling) to high-speed rotation that requires a relatively small torque (during high-speed traveling). It was difficult. According to Japanese Patent Application No. 4-5597, which was previously proposed by the applicant, a magnetic body provided on the rotor is slidably moved in the rotor axial direction by a hydraulic actuator, and a magnetic body between the magnetic body and the stator is moved. A configuration is shown in which the flux constant is changed to control the torque constant.

[0005]

However, in the conventional apparatus, a hydraulic actuator including a hydraulic cylinder and a hydraulic pump for sliding the magnetic body is provided, and a control unit for calculating and controlling the operation amount of the hydraulic actuator. Therefore, there is a problem in that the number of parts and weight increase. Furthermore, there is a problem that a control delay occurs due to the time required to calculate the control amount and the operation delay of the hydraulic actuator.

The present invention has been made to solve the above-mentioned problems, and the torque constant can be changed by changing the moving amount of the rotor magnetic body which can slide and move according to the traveling speed with a simple structure. It is an object of the present invention to provide a variable torque constant type wheel motor.

[0007]

In order to achieve the above object, a torque constant variable type wheel motor according to the present invention comprises a stator fixed to a housing and generating a magnetic flux.
A rotor that is rotatably supported on the axle inside the stator and that rotates together with the wheel; and a magnetic body that is arranged on the outer peripheral portion of the rotor and is slidable parallel to the rotation axis of the rotor. A weight that rotates integrally with the rotor and slides in the radial direction, a connecting member that connects the magnetic body and the weight, and a centrifugal force that acts on the weight when the wheel rotates act in a direction opposite to the centrifugal force. A return spring that applies an urging force to the magnetic body.

[0008]

The present invention has the above-mentioned structure, and the magnetic material arranged on the outer circumference of the rotor is slidably moved according to the vehicle speed, that is, the rotational speed of the wheel, to generate the stator and the rotor magnetic material. The torque constant is made variable by changing the number of magnetic flux linkages. The sliding movement of the magnetic body is performed against the biasing force of the return spring by the centrifugal force applied to the weight.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an embodiment of a variable torque constant type wheel motor according to the present invention. The variable torque constant type motor 10 is provided inside the wheel 12, and the rotor body 20 of the variable torque constant type motor 10 is fixed to the wheel 12 via the wheel flange 14 by bolts 16 and 18. Therefore, the motor 1
The rotation of 0 also rotates the wheel 12.

The rotor body 20 has a substantially cylindrical shape and is rotatably supported by the shaft portion 22 of the motor 10 by two bearings 24. Furthermore, serrations 26 are attached to the rotor body 20.
Is provided, and a magnet base 28 having a serration 28a fitted to the serration 26 is arranged slidably in the wheel axial direction. A permanent magnet 30 is arranged on the outer peripheral portion of the magnet base 28.

The stator 32 of the motor 10 is the housing 3
The core 36, which is fixedly arranged on the magnetic disk 4, is formed by laminating magnetic material plates such as silicon steel plates to face the permanent magnet 30. A coil 38 is wound around the core 36, and a magnetic flux is generated by supplying power to the coil 38, and the magnetic flux is linked to the permanent magnet 30.

The feature of the present embodiment is that the rotor body 20 described above is used.
A rotor flange 40 is fixed to the rotor flange 40, and a weight is provided on the rotor flange 40 so as to be slidable in the radial direction. The rotor flange 40 is fixed to the rotor body 20 with bolts 42 and rotates integrally with the rotor body 20. A weight guide 44 is provided on the rotor flange 40. The weight guide 44 has a tubular shape, and a weight 46 is housed inside the weight guide 44. The weight 46 is constrained by the weight guide 44 in the wheel circumferential direction and is slidable by a predetermined amount in the radial direction. This weight 4
6 and the magnet base 28 described above are connected by a cable 48, and a pulley 50 is fixedly arranged on the rotor flange 40 in order to correct different sliding directions. Further, when the magnet base 28 is located at the left end of the serration 26, the weight 46 is related so as to be located at the innermost side in its movable range. Further, a return spring 52 is arranged between the magnet base 28 and the rotor flange 40 so as to apply a biasing force to the left in the drawing.

Next, the operation will be described. When the vehicle is stationary, the wheels do not rotate, and the position of the magnet base 28 is at the left end of the serration 26, that is, the position shown in FIG. 1 due to the return spring 52. The number is also maximum. Therefore, the torque constant of the motor is maximized, and the motor is in a state suitable for low speed running such as when the vehicle starts with high torque.

When a current flows through the coil 38 and the rotor body 20 rotates, the wheel 12 rotates and the vehicle runs. As described above, the weight 46 rotates with the rotation of the rotor body 20, so that a centrifugal force is generated. This centrifugal force resists the biasing force of the return spring 52 from the magnet base 28 connected by the cable 48, Move to the right in the figure. Then, the magnet base 28 stops at a position where the centrifugal force and the urging force of the return spring 52 are balanced. FIG. 2 is a diagram showing a state where the movable range is moved to the right end. In this state, the number of interlinkage magnetic fluxes decreases, the torque constant also decreases, and the state becomes suitable for high speed rotation. That is,
As the number of interlinkage magnetic fluxes decreases, the torque constant (= back electromotive force constant) decreases and the back electromotive force also decreases, enabling higher-speed operation compared to a fixed magnet type motor.

Further, the return spring 52 has a non-linear spring characteristic, and an initial load is applied to the spring, that is, a biasing force remains even when the magnet base 28 is at the left end. The output torque characteristic can be changed.

Another embodiment is shown in FIG.
In addition to the return spring 52, a hydraulic damper 60 is provided. This prevents the weight 46 from abruptly returning and colliding with the weight guide 44 when wheel locking occurs during sudden braking.

As described above, the weight 46 is used in the two embodiments.
Are preferably arranged at equal intervals in the circumferential direction, and the same applies to the return spring 52 and the damper 60. For example, three weights 46 and three return springs 52 may be arranged alternately at 60 ° intervals.

[0018]

As described above, according to the present invention, the magnetic body can be moved by a simple structure, that is, the weight is provided and the centrifugal force applied thereto can move the magnetic body, and the positional relationship between the magnetic body and the stator. Can be changed. As a result, it is possible to operate from low speed high torque to high speed low torque.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the configuration of a preferred embodiment of a variable torque constant type motor according to the present invention.

FIG. 2 is a sectional view of an essential part for explaining the operation of the embodiment.

FIG. 3 is a sectional view showing the configuration of another embodiment of the present invention.

[Explanation of symbols]

 10 torque constant variable type motor 20 rotor body 28 magnet base 30 permanent magnet 32 stator 46 weight 48 cable 52 return spring

Claims (1)

[Claims] 1. A stator fixed to a housing to generate a magnetic flux, a rotor rotatably supported on an axle inside the stator, and rotatable together with a wheel, and a rotor disposed on an outer peripheral portion of the rotor. A magnetic body that is slidable parallel to the rotation axis of the rotor, a weight that rotates integrally with the rotor and slides in the radial direction, and a connecting member that connects the magnetic body and the weight. A return spring that applies a biasing force to the magnetic body that acts in a direction opposite to the centrifugal force applied to the weight when the wheel rotates, and the centrifugal force applied to the weight generated according to the wheel rotation speed A torque constant variable wheel characterized in that the torque constant is made variable by slidingly moving the magnetic body and changing the number of interlinkages of magnetic flux generated by the magnetic body and the stator. Motor.