Hydraulic powered park brake system
AssigneeInternational Truck Intellectual Property Company, LLC
InventorsRichard Randall Rowan, Steven Randall Lovell, Anton Leonard Rogness, III, Dale A Thomas, Anthony J Casale, David A Dornbach
Life of this patent
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Abstract
A hydraulic circuit for a motor vehicle supports operation of a power steering gear and a power assisted park brake unit incorporating a spring actuated hydraulic release (SAHR) chamber. The hydraulic circuit includes a pump with the power steering gear being connected to receive hydraulic fluid under pressure from the pump. Hydraulic fluid from the pump is delivered to first and second valves, the first or release control valve being connected to the SAHR chamber and the second or recirculation valve being coupled to return hydraulic fluid to a pump inlet.
Claims12
A hydraulic circuit for supporting operation of a power assisted steering and a power assisted park brake application, the hydraulic circuit comprising:
- a spring actuated hydraulic release chamber;
- a pump for pumping hydraulic fluid;
- a power steering gear connected to receive hydraulic fluid under pressure from the pump;
- a recirculation valve for selectively coupling hydraulic fluid from the power steering gear back to the pump;
- and
- a release control valve for selectively coupling hydraulic fluid from the power steering gear to the spring actuated hydraulic release chamber.
A powered park brake and power steering assist system comprising:
- a return line for hydraulic fluid;
- a pump connected to draw hydraulic fluid from the return line;
- a power steering gear connected to receive hydraulic fluid under pressure from the pump;
- a spring actuated hydraulic release chamber;
- an release control line connected to deliver hydraulic fluid to the spring actuated hydraulic release chamber;
- an outlet line from the power steering gear;
- a trap valve connected for transmission of hydraulic fluid between the outlet line and the release control line;
- a release control valve connected to the release control line;
- a recirculation valve connected for transmission of hydraulic fluid from the outlet line to the return line;
- a pressure actuated recirculation valve having a pressure responsive control input and connected for transmission of hydraulic fluid from the outlet line to the return line;
- and
- a pressure feedback line connected between the release control line and the pressure responsive control input of the pressure actuated recirculation valve.
A system for providing powered park brake operation, the system comprising:
- an open circuit power steering system;
- a spring actuated hydraulic release chamber;
- a recirculation valve for selectively coupling hydraulic fluid received from the power steering hydraulic circuit back to the power steering hydraulic circuit;
- a release control valve for selectively coupling hydraulic fluid from the power steering hydraulic circuit to the spring actuated hydraulic release chamber;
- a pressure actuated recirculation valve having a pressure responsive control input, the pressure actuated recirculation valve being connected in parallel with the recirculation valve to recirculate hydraulic fluid through the pump;
- a trap valve connecting the power steering hydraulic circuit to the release control valve;
- and
- a feedback line tapped to a connection between the release control valve and the trap valve, the feedback line providing the pressure input of the pressure actuated recirculation valve.
Dependencies are inferred from the claim text.