Husco International, Inc.

Deere & Company

Lynn A Russell

Eric P Hamkins

Raud A Wilke

Kristen Dawn Cadman

Michael C Layne

Steve Gary Fleischmann

Leif Pedersen

Mark J Jervis

Andreas S Pack

James E Olsen

Robert Jonathan Valenta

Sean M Haggerty

Michael J Clark

Mark Schultz

A vehicle with a load sensing hydraulic control system is disclosed.

Differential pressure control

A hydraulic system has several valve sections, each having a directional valve that controls fluid flow from a pump to a hydraulic actuator. A mechanism senses a greatest pressure among the hydraulic actuators to provide a load sense pressure. One valve sections has a pressure compensation apparatus includes a pressure compensation valve that reduces fluid flow between a given directional valve and an associated hydraulic actuator in response to pressure at a control port, and a pressure regulating valve that responds to the load sense pressure and pressure in the associated hydraulic actuator by selectively applying output pressure from the pump and the load sense pressure to the control port.

Control valve assembly with a workport pressure regulating device

An array of valve sections in a hydraulic system are connected to a supply line, a tank return line, and a load sense line. One valve sections includes a control valve with a metering orifice through which fluid flows from the supply line to a valve outlet. A load sense node is coupled by a load sense orifice to the load sense line. A load sense pressure limiter prevents pressure at the load sense node from exceeding a threshold level. A pressure compensator is connected in a fluid path between the valve outlet and one of the hydraulic actuators. The pressure compensator opens and closes the fluid path in response to pressure at the valve outlet and pressure at the load sense node, thereby governing the maximum amount of pressure that the respective valve section can apply to the hydraulic actuator.

Post-pressure compensated hydraulic control valve with load sense pressure limiting

A member that is driven by a hydraulic actuator tends oscillate when fluid flow to the hydraulic actuator is terminated. A pressure relief device reduces that oscillation by connecting first and second first relief valves to the hydraulic actuator. The first relief valve provides a relatively large first relief passage as long as pressure in the hydraulic actuator remains above a threshold. A second relief valve opens a second relief passage at substantially the same threshold pressure and thereafter remains open as long as the pressure remains above another lower threshold. A timer causes the second relief valve to close a given interval of time, if the pressure does not drop below the other lower threshold.

Valve assembly for attenuating bounce of hydraulically driven members of a machine

An improved pressure-compensated hydraulic system for feeding hydraulic fluid to one or more hydraulic actuators. A remotely located, variable displacement pump provides an output pressure equal to input pressure plus a constant margin. A pressure compensation systems requires that a load-dependent pressure be provided to the pump input through a load sense circuit. A reciprocally spooled, multiported isolator transmits the load-dependent pressure to the pump input but prevents fluid in the load sense circuit from leaving the load sense circuit and flowing through a relatively long conduit leading to the remotely located pump. In a multi-valve array, at least one valve section has a backflow-preventing shuttle valve which prevents backflow through the pressure compensation system if a main relief valve is operative.

Pressure compensating hydraulic control system

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Eagle, WI, United States of America

Lynn A Russell