| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a driving device for an electric vehicle which is speed variable and is highly efficient, without having to install a transmission mechanism thereto. <P>SOLUTION: A motor M having an outer rotor type rotor 6 and a stator 8, is equipped with an actuator 12, capable of moving the stator in the axial direction of the rotor to provide a variable field motor, allowing the opposed magnetic pole surfaces of the stator and the rotor to be changed. Gears 14a, 14b, having a fixed transmission ratio are provided to the rotor and wheels WR, and a chain 15, is hooked between both gears, to provide a chain transmission mechanism. Superior transmission efficiency can be secured without transmission loss by the transmission; and when the duty ratio for performing the duty control is reached to a preset duty limit value, the distance between the stator and the rotor is increased to control and weaken the magnetic field. This allows the motor characteristics to be of high-speed type, enabling speed variable performance equivalent to the driving device by using the transmission mechanism, and can prevent deterioration in the efficiency caused by the provision of the transmission mechanism. <P>COPYRIGHT: (C)2008,JPO&INPIT |
