Assist device for use in electric vehicles

A power assist device for use in a vehicle which includes a main switch, an accelerator, a running motor, and a motor driving circuit for controlling the rotation of the motor in response to the setting of the accelerator, the power assist device comprising:

• sudden start restraint means for, when the main switch is turned on with the accelerator in an opened state, restraining motor driving until the accelerator is closed;
• a dismount sensor for sensing a driver's dismount action from the vehicle and outputting a dismount signal after the driver dismounts the vehicle;
• accelerator setting determining means for determining whether the accelerator is in a closed state and outputting an accelerator closed state signal when the accelerator is in the closed state;
• speed mode setting means for setting the vehicle into an extremely slow speed mode when the driver dismounts the vehicle and when the accelerator setting is in a closed state, in response to the dismount signal from the dismount sensor and the accelerator closed state signal;
• and
• speed limit means for setting the rotational speed of the running motor in the extremely slow speed mode to be smaller than a normal value in a normal mode of the vehicle.

An electric vehicle, comprising:

• an accelerator;
• a running motor;
• a motor driving circuit for controlling the rotation of the motor in response to the setting of the accelerator;
• and
• a power assist device comprising:
• a dismount sensor for sensing a driver's dismount action from the vehicle and outputting a dismount signal after the driver dismounts the vehicle;
• accelerator setting determining means for determining whether the accelerator is in a closed state and outputting an accelerator closed state signal when the accelerator is in the closed state;
• speed mode setting means for setting the vehicle into an extremely slow speed mode when the driver dismounts the vehicle and when the accelerator setting is in a closed state, in response to the dismount signal from the dismount sensor and the accelerator closed state signal;
• and
• speed limit means for setting the rotational speed of the running motor in the extremely slow speed mode to be smaller than a normal value in a normal mode of the vehicle.