Rear-wheel steering apparatus for vehicles
AssigneeMazda Motor Corporation
InventorsHiroshi Ohmura, Masanobu Kosaka, Koji Hosoda
Life of this patent
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Abstract
A rear-wheel steering apparatus having a high-speed step motor revolving in accordance with a target steering angle ratio and a power cylinder for converting a change of the revolved angle of the motor to an amount of steering angle of rear wheels with a power assist by a hydraulic power. When a failure is detected in the rear-wheel steering system when the steering angle ratio is changed from in-phase to opposite phase, an oil pressure is released out of the power cylinder simultaneously with an interruption of current supply to the motor.
Claims16
A rear-wheel steering apparatus which controls a phase inversion of a steering angle ratio of rear wheels when a vehicle is turned, comprising:
- electric motor means for setting the steering angle ratio of the rear wheels adjustably with respect to the steering angle of front wheels;
- hydraulic driving means for driving the rear wheels with an oil pressure in accordance with the steering angle ratio set by said electric motor means;
- detection means for detecting a failed state in a rear-wheel steering control system;
- a fail-safe valve for releasing the oil pressure from said hydraulic driving means in order to force to return the steering angle of the rear wheels to a neutral position;
- and
- control means for controlling to stop said electric motor means and controlling said fail-safe valve to release the oil pressure from said hydraulic driving means in response to a detection of the failed state.
A rear-wheel steering apparatus which controls a phase inversion of a steering angle ratio of rear wheels when a vehicle is turned, the apparatus comprising:
- electric motor means for setting the steering angle ratio of the rear wheels adjustably with respect to the steering angle of front wheels;
- hydraulic driving means for driving the rear wheels with an oil pressure in accordance with the steering angle ratio set by said electric motor means;
- detection means for detecting a failed state in a rear-wheel steering control system;
- a fail-safe valve for releasing the oil pressure from said hydraulic driving means in order to force to return the steering angle of the rear wheels to a neutral position;
- and
- control means for controlling to interrupt a current to the electric motor means and for controlling said fail-safe valve to release the oil pressure from said hydraulic driving means in response to a detection of the failed state.
Dependencies are inferred from the claim text.