Force-Based Power Steering System
First Claim
Patent Images
1. A power steering system for a vehicle comprising:
- a pressurized fluid source;
at least one power cylinder;
a first valve operatively connected to the at least one power cylinder to control a steering direction; and
a second valve for controlling an amount of steering assist, the second valve having an input port fluidly connected to the pressurized fluid source and an output port fluidly connected to an input port of the first valve.
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Accused Products
Abstract
A power steering system includes a double-acting power cylinder (16) having a four-way valve (20) for controlling steering direction. An accumulator (26) stores pressurized fluid that is controllably supplied to the four-way valve (20) by an electronically controlled three-way valve (28) based upon an applied torque measured at a steering wheel (12).
25 Citations
25 Claims
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1. A power steering system for a vehicle comprising:
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a pressurized fluid source; at least one power cylinder; a first valve operatively connected to the at least one power cylinder to control a steering direction; and a second valve for controlling an amount of steering assist, the second valve having an input port fluidly connected to the pressurized fluid source and an output port fluidly connected to an input port of the first valve. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for operating a power steering system comprising
a) measuring applied torque on a steering wheel and providing a signal representative of the magnitude thereof; -
b) determining and providing a signal representative of a desired pressure value to be applied to an input port of a directional control valve as a function of at least the applied torque; c) measuring and providing a signal representative of an actual pressure value present at the input port of the directional control valve; d) comparing the signal representative of the actual pressure value to the signal representative of the desired pressure value; e) forming a power control signal based upon the comparison in said step d); and f) controlling a supply of pressurized fluid to the input port of the directional control valve in response to the power control signal in order to provide the desired pressure value to the input port of the directional control valve. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A power steering system for a vehicle comprising:
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an accumulator; a steering wheel; a four-way valve for controlling a steering direction, the four-way valve mechanically coupled to the steering wheel, the four-way valve selectively fluidly connecting an input port to a left output port or a right output port for controlling steering direction; and a three-way valve for controlling an amount of steering assist, the second valve having an input port fluidly connected to the accumulator and an output port fluidly connected to the input port of the four-way valve. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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Specification