Four-wheel vehicle steering apparatus
First Claim
1. A four-wheel steering apparatus for a vehicle having steerable front and rear wheels, comprising:
- in-phase steering control means for generating hydraulic output for steering the rear wheels in the same direction as that of the front wheels in accordance with a steering state of the front wheels;
antiphase steering control means, arranged in parallel to said in-phase steering control means, for generating hydraulic output for steering the rear wheels in a direction opposite to a direction in which the steering state of the front wheels changes, in accordance with a rate of change in the steering state of the front wheels; and
a hydraulic actuator receiving the hydraulic output from the in-phase steering control means to generate a steering force for steering the rear wheels in the same direction as that of the front wheels, receiving the hydraulic output from the antiphase steering control means to generate a steering force for steering the rear wheels in a direction opposite to a direction in which the steering state of the front wheels changes, and steering the rear wheels in accordance with a composite force of the steering forces.
1 Assignment
0 Petitions
Accused Products
Abstract
A four-wheel steering apparatus for a vehicle includes a hydraulic actuator for steering the rear wheels, and first and second oil pumps. An in-phase steering control valve is connected between the first oil pump and the actuator and outputs first hydraulic output for steering the rear wheels in phase with the front wheels in accordance with a steering state of the front wheels. An antiphase steering control valve is connected between the second oil pump and the actuator and outputs second hydraulic output for steering the rear wheels in opposite phase to the front wheels in accordance with a rate of change in the steering state of the front wheels. The hydraulic actuator combines the first and second hydraulic outputs from the control valves and steers the rear wheels in accordance with the difference between the hydraulic outputs.
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Citations
24 Claims
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1. A four-wheel steering apparatus for a vehicle having steerable front and rear wheels, comprising:
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in-phase steering control means for generating hydraulic output for steering the rear wheels in the same direction as that of the front wheels in accordance with a steering state of the front wheels; antiphase steering control means, arranged in parallel to said in-phase steering control means, for generating hydraulic output for steering the rear wheels in a direction opposite to a direction in which the steering state of the front wheels changes, in accordance with a rate of change in the steering state of the front wheels; and a hydraulic actuator receiving the hydraulic output from the in-phase steering control means to generate a steering force for steering the rear wheels in the same direction as that of the front wheels, receiving the hydraulic output from the antiphase steering control means to generate a steering force for steering the rear wheels in a direction opposite to a direction in which the steering state of the front wheels changes, and steering the rear wheels in accordance with a composite force of the steering forces. - View Dependent Claims (2, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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3. A four-wheel steering apparatus for a vehicle having steerable front and rear wheels, comprising:
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in-phase steering control means for generating hydraulic output for steering the rear wheels in the same direction as that of the front wheels in accordance with a steering state of the front wheels; antiphase steering control means, arranged in parallel to said in-phase steering control means, for generating hydraulic output for steering the rear wheels in a direction opposite to a direction in which the steering state of the front wheels changes, in accordance with a rate of change in the steering state of the front wheels; and a hydraulic actuator including a pair of first hydraulic chambers for receiving the hydraulic output from said in-phase steering control means to generate a steering force for steering the rear wheels in the same direction as that of the front wheels and a pair of second hydraulic chambers for receiving the hydraulic output from said antiphase steering control means to generate a steering force for steering the rear wheel in a direction opposite to a direction in which the steering state of the front wheels changes, for steering the rear wheels in accordance with a composite force of the steering forces. - View Dependent Claims (4, 5)
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22. A four-wheel steering apparatus for a vehicle having steerable front and rear wheels, comprising:
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power steering means for producing hydraulic pressure in accordance with a steering operation and assisting steering of the front wheels in accordance with the produced hydraulic pressure; first and second hydraulic sources; in-phase steering control means, connected to said first hydraulic source and said power steering means, for outputting, in accordance with the hydraulic pressure produced by the power steering means, hydraulic pressure supplied from said first hydraulic source as first hydraulic output for steering the rear wheels in phase with the front wheels; antiphase steering control means, connected to said second hydraulic source and said power steering means, for outputting, in accordance with a rate of change in the hydraulic pressure produced by said power steering means, hydraulic pressure supplied from said second hydraulic source as second hydraulic output for steering the rear wheels in opposite phase to the front wheels; and a hydraulic actuator, connected to said in-phase and antiphase steering control means, for combining the first and second hydraulic outputs and steering the rear wheels in accordance with the difference between the first and second hydraulic outputs.
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23. A four-wheel steering apparatus for a vehicle having steerable front and rear wheels, comprising:
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first and second hydraulic sources; a first hydraulic actuator for steering the rear wheels; a second hydraulic actuator for steering the rear wheels; in-phase steering control valve means, arranged between said first hydraulic source and said first hydraulic actuator, for guiding hydraulic pressure from said first hydraulic source to said first hydraulic actuator to steer the rear wheels in phase with the front wheels in accordance with a steering state of the front wheels; and antiphase steering control valve means, arranged between said second hydraulic source and said second hydraulic actuator, for guiding hydraulic pressure from said second hydraulic source to said second hydraulic actuator to steer the rear wheels in opposite phase to the front wheels in accordance with a rate of change in the steering state of the front wheels.
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24. A four-wheel steering apparatus for a vehicle having steerable front and rear wheels, comprising:
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first and second hydraulic sources; a first hydraulic actuator for steering the rear wheels; a second hydraulic actuator for steering the rear wheels; steering gear ratio variable control means for correcting a steering angle of the front wheels; in-phase steering control valve means, arranged between said first hydraulic source and said first hydraulic actuator, for guiding hydraulic pressure from said first hydraulic source to said first hydraulic actuator to steer the rear wheels in phase with the front wheels in accordance with a steering state of the front wheels; and antiphase steering control valve means, arranged between said second hydraulic source and said second hydraulic actuator and between said second hydraulic source and said steering gear ratio variable control means, for guiding hydraulic pressure from said second hydraulic source to said second hydraulic actuator and said variable control means to steer the rear wheels in opposite phase to the front wheels in accordance with a rate of change in the steering state of the front wheels and to increase the steering angle of the front wheels.
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Specification