Electric power steering system
First Claim
1. An electric power steering system for a motor vehicle, comprisinga motor operatively connected to a steering system for reducing steering effort,a vehicle speed sensor for producing a vehicle speed signal,a torsion torque sensor provided for detecting torsion torque which is generated in the steering system during a steering operation,assist means responsive to an output signal of the torsion torque sensor for producing an assist signal,driving means responsive to the assist signal for producing a signal for driving the motor,a steering angle sensor provided for detecting steering angle of a steering wheel for producing a steering angle signal,first means responsive to said vehicle speed signal and said steering angle signal for producing a lateral acceleration signal dependent on lateral acceleration exerted on the motor vehicle while said vehicle speed signal is lower than a predetermined value,second means responsive to the lateral acceleration signal for producing a first return torque signal dependent on the lateral acceleration, andthird means for adding the first return torque signal to the assist signal to operate the motor dependent on the first return torque signal via said driving means to return the steering wheel, so as to prevent returning delay of the steering wheel at turning of a corner under high lateral acceleration.
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Accused Products
Abstract
A system having a motor operatively connected to a steering system for reducing the steering effort. The system is provided with a torsion torque sensor provided for detecting torsion torque generating in the steering system in steering operation. In response to the output signal of the torsion torque sensor, an assist signal is produced. A return torque signal dependent on the lateral acceleration exerted on a motor vehicle is generated. The return torque signal is added to the assist signal, thereby operating the motor to return a steering wheel.
23 Citations
14 Claims
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1. An electric power steering system for a motor vehicle, comprising
a motor operatively connected to a steering system for reducing steering effort, a vehicle speed sensor for producing a vehicle speed signal, a torsion torque sensor provided for detecting torsion torque which is generated in the steering system during a steering operation, assist means responsive to an output signal of the torsion torque sensor for producing an assist signal, driving means responsive to the assist signal for producing a signal for driving the motor, a steering angle sensor provided for detecting steering angle of a steering wheel for producing a steering angle signal, first means responsive to said vehicle speed signal and said steering angle signal for producing a lateral acceleration signal dependent on lateral acceleration exerted on the motor vehicle while said vehicle speed signal is lower than a predetermined value, second means responsive to the lateral acceleration signal for producing a first return torque signal dependent on the lateral acceleration, and third means for adding the first return torque signal to the assist signal to operate the motor dependent on the first return torque signal via said driving means to return the steering wheel, so as to prevent returning delay of the steering wheel at turning of a corner under high lateral acceleration.
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13. An electric power steering system for a motor vehicle, comprising
a motor operatively connected to a steering system for reducing steering effort, a torsion torque sensor provided for detecting torsion torque which is generated in the steering system during a steering operation, assist means responsive to an output signal of the torsion torque sensor for producing an assist signal, driving means responsive to the assist signal for producing a signal for driving the motor, first means for producing a varying lateral acceleration signal dependent on lateral acceleration exerted on the motor vehicle, second means responsive to the lateral acceleration signal for producing a varying first return torque signal as a function of the lateral acceleration, and third means for adding the first return torque signal to the assist signal to operate the motor as a varying function dependent on the first return torque signal via said driving means to return the steering wheel, so as to prevent returning delay of the steering wheel at turning of a corner under high lateral acceleration.
Specification