Motor-driven power steering system for vehicles
First Claim
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1. A motor-driven power steering system for an automotive vehicle, comprising:
- an input shaft coupled to a steering wheel;
an output shaft coupled to a dirigible wheel;
an electric motor applies an assistive torque to said output shaft;
steering torque detecting means for detecting a steering torque applied to said input shaft;
drive control means, responsive to detected signals from said steering torque detecting means, for applying a driving signal to said electric motor;
freely returning state detecting means for detecting a freely returning state of said steering wheel to generate a motor damping signal when prescribed conditions are met;
speed detecting means for detecting the speed of travel of the automotive vehicle;
widening range means for widening the range of the prescribed conditions for detecting the freely returning state of said steering wheel in response to an increase in the detected speed of travel of the automotive vehicle; and
damping means responsive to the motor damping signal for damping said electric motor.
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Abstract
A motor-driven power steering system for an automotive vehicle has a drive control device for applying a driving signal to an electric motor for generating assistive torque to be applied to an output shaft, based on output signals from a torque detecting mechanism which detects a steering torque acting on an input shaft. The system detects a freely returning state of a steering wheel to dampen the electric motor when prescribed conditions are met. The range of the prescribed conditions is widened as the speed of travel of the automotive vehicle is increased.
73 Citations
5 Claims
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1. A motor-driven power steering system for an automotive vehicle, comprising:
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an input shaft coupled to a steering wheel; an output shaft coupled to a dirigible wheel; an electric motor applies an assistive torque to said output shaft; steering torque detecting means for detecting a steering torque applied to said input shaft; drive control means, responsive to detected signals from said steering torque detecting means, for applying a driving signal to said electric motor; freely returning state detecting means for detecting a freely returning state of said steering wheel to generate a motor damping signal when prescribed conditions are met; speed detecting means for detecting the speed of travel of the automotive vehicle; widening range means for widening the range of the prescribed conditions for detecting the freely returning state of said steering wheel in response to an increase in the detected speed of travel of the automotive vehicle; and damping means responsive to the motor damping signal for damping said electric motor. - View Dependent Claims (2, 3, 4, 5)
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Specification