Applied Power Inc.

Parker-hannifin Corporation

James P Janecke

Dale A Knutson

Kishor J Patel

Frank M Fritz

Carl-Johan Omberg

Thomas J Stobbs

Ronald C Koltz

A three-way valve assembly, including a valve body having a fluid flow path and a valve member movable in the fluid flow path between a supply port and a work port, and between a load sense passage and a pressure relief port. The valve member may move between a first position and a second position for controlling flow and regulating fluid pressure differences sensed in the flow path; and for limiting fluid pressure in the flow path to a predetermined pressure level set by a pilot-operated pressure limiter valve when the valve member is in the second position. The valve member may move between the second position and a third position to open the flow path from the load sense passage to the pressure relief port for relieving fluid pressure in the flow path when the fluid pressure from an over-loaded actuator exceeds the predetermined pressure level set by the pressure limiter valve.

Three-way pressure control and flow regulator valve

A hydraulic circuit for controlling the speed of multiple hydraulic fluid power devices when the flow demand of the devices exceeds the flow capacity of a pressure source supplying hydraulic fluid under pressure to the devices has multiple pressure controlled proportional flow supply valves for controlling the supply of hydraulic fluid to the power devices. Load sense pressures which indicate the pressure delivered by the valves to the corresponding devices are compared to determine the highest load sense pressure, which is compared to the supply pressure by a proportional speed sensing valve to regulate the pilot pressure. In the preferred embodiment, the pilot pressure is regulated by the proportional speed sensing valve to be equal to the differential between the supply pressure and the highest load sense pressure, and a limit control is provided in one form of the proportional speed sensing valve. Thus, when the differential between supply pressure and the highest load sense pressure starts falling, as occurs when the flow demand exceeds the flow capacity of the pump, the pilot pressure is reduced, which reduces flow to the power devices proportionally to reduce the speeds of the devices while maintaining substantially constant the proportions of the speeds to one another.

Proportional speed control of fluid power devices

A hydraulic circuit for controlling the speed of multiple hydraulic fluid power devices when the flow demand of the devices exceeds the flow capacity of a pressure source supplying hydraulic fluid under pressure to the devices has multiple pressure controlled proportional flow supply valves for controlling the supply of hydraulic fluid to the power devices. Load sense pressures which indicate the pressure delivered by the valves to the corresponding devices are compared to determined the highest load sense pressure, which is compared to the supply pressure by a proportional speed sensing valve to regulate the pilot pressure. In the preferred embodiment, the pilot pressure is regulated by the proportional speed sensing valve to be equal to the differential between the supply pressure and the highest load sense pressure, and a limit control is provided in one form of the proportional speed sensing valve. Thus, when the differential between supply pressure and the highest load sense pressure starts falling, as occurs when the flow demand exceeds the flow capacity of the pump, the pilot pressure is reduced, which reduces flow to the power devices proportionally to reduce the speeds of the devices while maintaining substantially constant the proportions of the speeds to one another.

A direct-operated, two-way solenoid valve is disclosed. The valve balances the hydraulic flow forces acting on a poppet in order to achieve fast-acting, high-flow operation. The valve has a housing with the poppet mounted in a main bore. The poppet has a sealing end with a longitudinal central bore that is open at the sealing end and terminates in a pressure wall. A radial cross bore in the poppet provides fluid communication between the central bore and an outlet port formed in the housing. The sealing end of the poppet may contact a valve seat to prevent fluid communication between an inlet port formed in the housing and the central bore of the poppet. The sealing end of the poppet is biased into contact with the valve seat to prevent fluid communication between the inlet port and the central bore. An actuator generating a magnetic flux path tends to move the poppet out of contact with the valve seat.

Fluid control valve

A compact, high response regulating valve has a solenoid modulated armature and plunger construction. The solenoid assembly and armature minimize magnetic flux leakage by maintaining the armature in close proximity to the induced magnetic field. In one embodiment, the lightweight armature has a number of holes to increase the speed at which it may be modulated. Mounted to the armature is a regulator plunger which controls fluid communication between the valve's inlet and outlet ports. Normally spring-biased closed, the plunger uses a line seal to maximize flow with minimal longitudinal plunger movement. Plunger response time is enhanced by eliminating elastomeric friction (i.e., eliminating O-rings and replacing them with a number of notches about the plunger periphery). A conical seat and bevelled plunger provide an effective line seal.

High response, compact solenoid two-way valve

An individual segment flow regulator is shown having a two landed spool and two landed bore, all with the same nominal diameter, a plug, a spring and a sensing passage from the main spool of the valve. Supply oil entering between the two lands of the bore is separated from a sensing pressure by one spool land which is slidable within the bore. The other spool land meters the supply fluid. The metering land of the regulator spool opens away from the valve bore land to allow supply fluid through and can shut off the supply. A spring chamber above the spool senses the load pressure which opens the metering spool, thereby increasing the flow and therefore the pressure drop across the main spool area opening. Feedback pressure developed at the bottom of the metering land of the spool is used to close down the regulator spool as the flow, and therefore the pressure drop, across the main spool increases beyond the pre-load force of the bias spring. The feedback land at the bottom of the spool is also the metering land that controls supply pressure to the regulated pressure.

Compensated individual segment flow regulator

A hydraulic pressure control valve includes a modulator-controlled solenoid assembly which selectively axially displaces a disc armature adjacent thereto. When not attracted by the solenoid, the armature is biased away from the solenoid by a wave spring. Movement of the armature opens and closes the outlet of a lower body member to a source of hydraulic fluid under pressure. The armature is improved, having dimples on the face adjacent the solenoid assembly to minimize sticking. Additionally, the center pole of the solenoid is axially adjustable and can therefore be set for different valve performance levels. Assembly of the valve is quickly accomplished using pneumatic pressure under performance conditions for adjustment of and setting the initial displacement of the disc armature. Setting is accomplished by crimping the various components in an outer tube.

Modulating hydraulic pressure control valve and assembly method therefor

A hydraulic pressure control valve includes a spool which has a first end having a first cross-sectional area. The opposite end of the spool has a reduced cross-sectional area. Modulated pressure is provided to a chamber at the first end of the spool and when it increases beyond the force of a biasing spring, an inlet port is connected to an outlet port. Feedback pressure acts on the differential area between a full cross-sectional area of the spool and a reduced area portion of the spool located within the outlet port. The feedback force on the spool is in proportion to the changing control force. A sleeve is provided at the end of the valve adjacent the reduced area portion of the spool, such portion and sleeve cooperating to provide a sliding seal. The outlet port will be coupled to tank whenever the modulated pressure falls below the combination of the spring force and the feedback pressure.

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Waukesha, WI, United States of America

James P Janecke