Bosch Rexroth Ag

Robert Boschgmbh

Mannesmann Rexroth Corporation

Mannesmann Rexroth Ag

Wolfgang Kauss

Didier Desseux

Matthieu Desbois-Renaudin

Armin Stellwagen

Gerard Laroze

Frederic Lamarche

Vincent Guyard

Emmanuel Remi Richer

Benoit Galtier

A hydraulic control arrangement includes a common variable displacement pump configured to supply pressure medium to two consumer groups. The pressure level of a control block assigned to one of the consumer groups is set to a different pressure level than that of a further control block assigned to the other consumer group.

Hydraulic control arrangement

A hydraulic pilot control unit includes at least one pressure control valve that can be controlled by means of an actuating device. The pressure control valve includes a control piston connected to a stem by means of a neck. The stem has a resilient operative connection to the actuating device. The neck is fastened to the stem. Thus, the mass of the control piston, which tends to oscillate, is reduced compared to the prior art.

Hydraulic pilot control unit

The invention relates to a hydraulic control arrangement for supplying a pressure medium to at least one consumer. The forward line and/or the return line of the consumer comprises a distributing valve that can be continuously controlled and that has two switch positions, and a lowering brake valve that can be placed in an open position due to the pressure in the supply line. The distributing valve is in an open neutral position and can be displaced, electrically or electrohydraulically, from said neutral position into the direction of the second switch position thereof.

Hydraulic control system

The invention relates to a hydraulic control arrangement and to a method for controlling a hydraulic consumer that comprises a pressure chamber on the input side and on the return side, said pressure chamber being connected to an adjusting pump or a tank via a valve device. The valve device is controlled by means of a control unit via which it can be adjusted in a regeneration mode, in which both pressure chambers are connected to the adjusting pump. According to the invention, the adjusting pump is pressure controlled, whereby in the regeneration mode, it is automatically switched to the normal operation in which the supply side of the pressure chamber is connected to the adjusting pump and the return side of the pressure chamber is connected to the tank when the pumping rate falls below the demand for the pressure medium.

Method and hydraulic control system for supplying pressure medium to at least one hydraulic consumer

A hydraulic control assembly, in particular for controlling hydraulic consumers of a mobile machine, includes a load reporting line () that can be subjected to the highest load pressure of a plurality of hydraulic consumers, triggered simultaneously each via a respective main control valve (), and that is connectable by an end portion () to a pump regulator (). A pressure limiting valve () limits the control pressure in the end portion () of the load reporting line (). The pressure limiting valve () is adjustable as a function of the magnitude of a pilot control signal serving to trigger a main control valve ().

Hydraulic control assembly

A hydraulic control device according to the invention is of load-sensing design and serves to actuate a first hydraulic load and a second hydraulic load. Also provided are a first control valve for actuating the first hydraulic load and a second control valve for actuating the second hydraulic load. A first load signal can be measured on the basis of a load pressure with which the first hydraulic load is acted on, and a second load signal can be measured on the basis of a load pressure with which the second hydraulic load is acted on. Pressure medium from a pressure medium source can be supplied in parallel to the first control valve and to the second control valve. A load signal path can, in order to actuate an adjusting element which is assigned to the pressure medium source, be acted on with a highest presently measured load signal. A limiting device allows the second load signal to be limited to a predefined signal limit value. A switching means can be actuated by means of the second load signal such that, at the latest when the second load signal reaches the signal limit value, the signal conveyed on the load signal path is limited by the limiting device.

Hydraulic control device

The invention relates to a hydraulic control system for providing at least one hydraulic consumer with a pressure medium. Said system comprises an LS pump system and a metering port for adjusting the pressure medium volume flow rate towards the consumer. The LS line is connected to a pressure medium sink via a current regulator. The invention is characterized in that the current regulator can be adjusted depending on the pump rate in order to modify the pressure drop at the metering port.

The invention relates to a hydraulic control device for a priority, first hydraulic consumer and a subordinate, second hydraulic consumer, pressure medium being deliverable to the first or the second consumer via a first or a second metering diaphragm. A pressure scale which allows a constant pressure difference to be adjusted above the first metering diaphragm is mounted upstream from the first metering diaphragm. For this purpose, said pressure scale is provided with a valve piston encompassing a first control edge, by means of which a first flow area between a feeding duct and the first metering diaphragm can be controlled. A second control edge which allows a second flow area to be controlled between the feeding duct and a load signaling line is provided on the valve piston of the first pressure scale.

A hydraulic control arrangement is disclosed for the load-independent control of a consumer with a continuously adjustable distribution valve having a pressure compensator down the line. According to the invention, the pressure compensator has a single-sided damping such that the movement in the opening direction is damped and the movement in the closing direction is substantially undamped. Furthermore, a control arrangement is disclosed in which a load-holding function is integrated in the pressure compensator.

What is disclosed is a hydraulic control system for a mobile equipment, in particular for a wheel or backhoe loader, wherein a shovel is linked to a boom. The angular position of the shovel may be kept constant through the intermediary of an orientation control device during a pivoting movement of the boom relative to the axles of the equipment. In accordance with the invention, the orientation control device is realized such that in the event of a change of a pre-set angular position, a control signal is generated through a pilot control device, whereby a shovel control unit may be controlled in such a manner that the shovel is again returned into its predetermined angular position.

Hydraulic control system for mobile equipment

On a work appliance, an extension arm is held rotatably, and a scoop is held rotatably on the extension arm. Actuation of the extension arm and of the scoop is by means of hydraulic cylinders. Each cylinder is assigned a valve which controls the flow of pressure medium from a pump to the cylinder and from the latter to the tank. A rotational movement of the extension arm is accomplished with the top edge of the scoop maintaining its angular position when the extension arm is being raised or lowered. Valves which control the flow of pressure medium to the cylinders are activated with the ratio of the pressure medium quantities supplied to the cylinders being kept at a constant value independently of the size of the control signal controlling the flow of pressure medium to a cylinder for the actuation of the extension arm.

Control device for a work device comprising a scoop held on an extension arm

What is disclosed is a hydraulic control system for controlling a hydraulic consumer actuating a working tool of a mobile equipment that is provided with oscillation damping means for attenuating oscillations during braking of the working tool. In accordance with the invention, the oscillation damping means comprise two pilot-controlled shut-off valves arranged in opposite directions, that are positioned in a connecting line between a pressure medium supply and a pressure medium drain. The shut-off valves are subjected to the pressure in the drain and in the delivery, respectively, in the opening direction, and also to this pressure and to the force of a spring in the closing direction. Following a predetermined initial stroke of a regulator of the control system, the pressure acting on the drain-side shut-off valve in the closing direction may be reduced, so that the latter is opened by the pressure in the drain, and the connecting line between delivery and return is opened.

A hydraulic control arrangement is disclosed for the control of a consumer, comprising at least one mechanically operated continuously adjustable distribution valve with a subsequent LUDV pressure compensator down the line. In order to lock the consumer the control arrangement is provided with a spring holding the pressure compensator piston in a closed position. Furthermore, the LS line carrying the highest load pressure of all consumers is connected to a reservoir by means of a flow regulator, wherein the pump control may also be relieved by the flow regulator in the sense of a reduction of the pumped volume. According to the invention, the LUDV pressure compensator is pressure-compensated by means of a nozzle through which a connection between the LS line and a portion of the pressure medium flow path downstream of the pump and upstream of the outlet of the pressure compensator is generated. Said nozzle is preferably integrated in the pressure compensator piston.

What is disclosed is a hydraulic control arrangement for a mobile equipment, such as for a backhoe loader or a wheel loader, wherein a working tool of the equipment is adapted to be actuated by means of a hydraulic cylinder whose pressure chambers may jointly be connected with a hydraulic accumulatorfor attenuating pitching oscillations of the working tool.

Hydraulic control arrangement for a mobile equipment

What is disclosed is a control arrangement for an equipment, in particular a wheel loader or a backhoe loader having a shovel mounted articulatedly at a boom, wherein the control arrangement enables a control of the shovel by means of a control pressure of a boom control unit, so that the latter may be taken into a target position during lowering of the boom or while the boom is taken into a floating condition.

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Francheville, France

Wolfgang Kauss