Motor-driven power steering system
AssigneeAisin Seiki Kabushiki Kaisha
InventorsAkio Hashimoto, Tomio Yasuda
Life of this patent
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Abstract
A power steering system makes use of a direct-current servomotor to produce an auxiliary torque added to the torque which is applied to the steering wheel of a vehicle by the driver. The system includes an electronic apparatus, which receives a signal indicating the velocity of the vehicle, divides the whole range of the vehicle velocity into at least three ranges, and determines under which of these ranges the present velocity falls. In the lowest range, the control apparatus energizes the motor to produce such an auxiliary torque. In the middle range, the apparatus de-energizes the motor and so no auxiliary torque is generated. In the highest range, the apparatus connects a load such as a resistor with the coil in the motor to brake the rotation of the steering wheel.
Claims5
A motor-driven power steering system comprising:
- an electric motor,
- coupling means for coupling the motor to the steering shaft of a vehicle,
- torque detecting means for detecting the steering torque applied by the driver,
- a motor braking means connected to the coil in the motor, and
- an electronic control apparatus for dividing the range of the velocity of the vehicle into at least three ranges, the control apparatus energizing the motor according to the output signal from the torque detecting means in the first range of the velocity, the control apparatus de-energizing the motor in the second range of the velocity, the control apparatus energizing the braking means in the third range of the velocity.
Dependencies are inferred from the claim text.