Sauer-Danfoss Inc.

Charles D Throckmorton

Michael D Gandrud

Jimmy W Bolinger

Chad J Daniel

Stephen D Cromer

Michael J Stoltenow

Glenn M Mahony

A hydraulic pressure control system having a variable displacement pump fluidly connected to a hydraulic motor. The pump provides flow to a first circuit upon demand. Remaining flow is provided to a second circuit. The second circuit includes a pilot controlled pressure reducing valve that adjusts the pumps outlet pressure based upon a sensed loads taken from a conduit between the pressure control valve and an active flow regulator valve.

Dynamically stable pressure control system

A hydrostatic transmission having a hydraulic pump that is fluidly connected to a hydraulic motor. The transmission also has a pressure control valve that has first and second stages and is fluidly connected to the hydraulic pump. By utilizing the pressure control valve when the first stage of the pressure control is at a minimum pressure the second stage determines the minimum charge pressure setting for the hydrostatic transmission.

Hydrostatic transmission having proportional pressure variable displacement pump for loop charge and fan flow supply

A priority circuit is provided that is in communication with an open circuit pump and priority and auxiliary systems. The circuit comprises a first valve with an inlet in communication with the pump, an outlet in communication the priority system, and a load sensing inlet in communication with the priority system, wherein the first valve modulates to maintain a predetermined pressure differential between pressure at the load sensing inlet and pressure at the outlet. The circuit further comprises a second valve with an inlet in communication with the pump, an outlet in communication with the auxiliary system, and a load sensing inlet in communication with the priority system, wherein the second valve is normally closed and opens when pressure at the load sensing inlet of the second valve is less than pressure at the inlet of the second valve minus the predetermined pressure differential of the first valve.

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Ames, IA, United States of America

Charles D Throckmorton