Robert Boschgmbh

Heinz Kleinschmidt

Heinz Flaschar

Peter Kroll

Klaus Sopha

Heinz Gand

Rainer Hoheisel

Joachim Heiser

Roland Schempp

Horst Hesse

Winfried Arnold

Hermann Sanzenbacher

Walter Kobald

Gunter Fischer

Hugo Preun

Werner Zeuch

Petrus Thomassen

Konrad Braunlinger

A two-way pressure-control valve has a housing formed with an axially extending bore adjacent whose front end opens a front port and adjacent whose rear end opens a rear port. A valve body is slidable in the bore between the rear port and the front end and a piston is slidable in the bore between the rear end and the rear port. Thus the valve body can slide across the front port and block fluid flow between the ports via the bore, and the valve body and the piston define a front compartment, a middle compartment always connected to the rear port and connectable to the front port when the valve body is moved forwardly, and a rear compartment. A passage is formed in the housing for connecting the front port to the rear compartment so that the pressure in the middle and rear ports is always effective across the piston. In addition the valve body is formed with an axially through-going small-diameter orifice that allows pressurization of the front compartment to the same pressure as the middle compartment. The front compartment is connected to the front port via a pilot valve that opens when a predetermined pressure differential is exceeded. Finally a spring biases the valve body rearwardly into a position blocking the front port. Such a valve opens whenever the pressure in either of the ports exceeds the pressure in the other port by a predetermined pressure differential.

Two-way pressure-control valve

A control arrangement for supplying pressure fluid through a supply conduit from a source of pressure fluid to at least two hydraulically operated consumer devices includes, for each of the consumer devices, a valve having a valve member movable axially between a neutral position preventing flow of pressure fluid to the respective consumer device and two working positions respectively connecting the consumer device to the source of pressure fluid or a return conduit. A throttle is located in the supply conduit between a first point of the latter from which a first branch conduit branches off to a first of the valves and a second point from which a second branch conduit branches off to the second of the valves. The arrangement includes further a control valve and a control circuit therefor, controllable at least by the valve member of one of the valves. In the neutral position of all valve members the supply conduit is connected with the return conduit to form therewith a neutral fluid circulation passage.

Control arrangement for supplying pressure fluid to at least two

A hydraulic control system has a three-position valve which in its central position disconnects the high-pressure and low-pressure sides of a pressure source from outlet lines but connects these sides of the source together through a low-pressure valve. Moved to either of its end positions the valve is disconnected from between the sides of the pressure source and the output lines are connected to the high-pressure and low-pressure source sides. A pressure-limiting valve is connected between the sides of the source. In addition, the high-pressure side is connected via pressure-reducing valve and a restriction to a pair of pilot valves which are in turn connected to the low-pressure side. These pilot valves are also connected to opposite chambers of a pilot cylinder that controls the valve body. The pressure-reducing valve between the pilot valves and the high-pressure side maintains a medium-pressure level in the system when the valves move from its central position.

Hydraulic control system

An electrohydraulic control unit which regulates the flow of hydraulic fluid to and from one or more consumers by way of a directional control valve has a cylinder for a piston which is mechanically connected with or constitutes the spool of the directional control valve and divides the interior of the cylinder into two plenum chambers connected to the outlet of the pump, either directly or by way of a pressure reducing valve. The chambers are further connected with the tank and each of the fluid supplying and evacuating conduits for each of the two chambers contains a flow restrictor. Th flow restrictors in conduits for admission of fluid to the chambers are mounted upstream of check valves and the flow restrictors in conduits for evacuation of fluid from the chambers are mounted upstream of or constitute integral parts of two solenoid-operated auxiliary valves. The four flow restrictors together constitute a hydraulic bridge circuit.

Electrohydraulic control unit

Growing community of inventors

Stuttgart, Germany

Heinz Kleinschmidt