Husco International, Inc.

Gary J Pieper

Eric P Hamkins

Jason Greenwood

Corey Quinnell

Andreas S Pack

Jacob Ballweg

Jonathan M Starkey

A system has a variable displacement pump that supplies pressurized fluid to power a plurality of hydraulic functions. Each hydraulic function has a control valve with a variable source orifice controlling fluid flow between the pump and a flow summation node, and a variable metering orifice controlling fluid flow between the flow summation node and a hydraulic actuator. Variable bypass orifices in the control valves are connected in series between the flow summation node and a tank. As the metering orifice in a control valve enlarges, the source orifice enlarges and the bypass orifice shrinks. This alters pressure at the flow summation node, which is used to control the output of the pump. Components are provided to give selected hydraulic functions different levels of priority with respect to consuming fluid flow from the pump.

Hydraulic system with fluid flow summation control of a variable displacement pump and priority allocation of fluid flow

A hydraulic valve assembly includes a pressure compensating valve in which a compensator spool is slideably received in a bore. A pre-compensator gallery connected to a metering orifice, a preload gallery leading to a hydraulic actuator, an auxiliary pump supply passage, and a load sense passage all open into the bore. The compensator spool moves in response to a pressure differential between the pre-compensator gallery and the load sense passage. That movement selectively opens and closes a first path between the pre-compensator gallery and the a preload gallery, and a second path between the auxiliary supply passage and the load sense passage. Control of these paths maintains a constant pressure drop across the metering orifice and generates a pressure signal that is employed to regulate pressure at an outlet of a pump.

Hydraulic control valve system with isolated pressure compensation

An assembly of a plurality of hydraulic control valves is housed in a single-piece body. For each control valve, a spool bore and an aperture for a pressure compensation valve are provided in the monolithic body. Each spool bore is connected to several return passages and a supply passage that extend through the monolithic body. A pair of workports also is connected to each spool bore. A relief valve return passage also extends through the monolithic body and where needed, apertures for pressure relief valves extend from a surface of the monolithic body intersecting the relief valve return passage and a given workport. A load sense passage and a second supply passage also are formed in the monolithic body.

Multiple hydraulic spool valve assembly with a monolithic body

An apparatus and method for controlling hydraulic output to a plurality of actuatable devices are disclosed. The apparatus includes a plurality of main valves coupled, respectively, to the actuatable devices and to respective secondary valves, and also an adjustment valve that is coupled between a pressure source and one or more of the secondary valves. The adjustment valve receives a first indication of a pressure at the one or more secondary valves, and a second indication related to a highest load pressure. The adjustment valve allows pressure to be provided from the pressure source to the one or more secondary valves when the second indication exceeds the first indication, such that an equal amount of fluid flow occurs with respect to each of those secondary valves that is reduced in comparison with the fluid flow to any other secondary valves that are not connected to the adjustment valve.

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Eagle, WI, United States of America

Gary J Pieper