Bosch Rexroth Ag

Robert Boschgmbh

Heinrich Loedige

Gerhard Keuper

Peter Stachnik

Soenke Jessen

Milan Djurovic

Christoph Keyl

Reiner Kunz

Disclosed is a lifting gear valve arrangement for controlling a double-action lifting gear or an add-on unit with a continuously adjustable directional control valve and with an individual pressure compensator via which a pressure medium volume flow to and from a lifting cylinder of the lifting gear can be controlled. A proportionally adjustable pressure limiting valve is provided in the pressure medium flow path between an outlet connection of the directional control valve and a working connection of the lifting gear valve arrangement, via which the pressure inside this area can be limited to a maximum value. The adjustment of the pressure limiting valve is preferably performed as a function of the operating states of the lifting gear or of the type of add-on unit.

Lifting gear valve arrangement

A hydraulic control system for controlling preferably at least two consumers, has a pump supplying the consumers with a pressure medium and having an adjustable pump capacity, an adjustable metering orifice assigned to each of the consumers, a power-beyond connection to which at least one power-beyond consumer is attachable, an inlet pressure scale connected downstream of the pump and provided in a pressure medium flow path between the pump and at least one of the two consumers, wherein the power-beyond connection branches off in the pressure medium flow path between the pump and the inlet pressure scale, a spring with a force acting upon the inlet pressure scale in a closing direction, an inlet having a pressure acting upon the inlet pressure scale in an opening direction, wherein the inlet pressure scale is configured so that it is actable upon in the closing direction selectively by either a highest load pressure or by a pressure that is greater than the highest load pressure.

Hydraulic control system

A hydraulic control system for controlling preferably at least two consumers, has a pump with an adjustable delivery quantity supplying pressure fluid, an adjustable metering orifice with which the consumers are each associatable, a power beyond connection to which at least one power beyond consumer is connectable, an inlet pressure governor unit situated downstream of the pump and acted on in a closing direction by a load pressure of the consumers or of the at least one power beyond consumer, the inlet pressure governor unit being provided in a pressure fluid flow path between the pump and at least one of the two consumers, while the power beyond connection branching off from a pressure fluid flow path between the pump and the inlet pressure governor unit, a tank, the inlet pressure governor unit in a spring-prestressed position closing a connection to the at least one of the two consumers and the tank, and in another position a pressure fluid connection to the tank is opened, the inlet pressure governor unit being movable into an additional position in which a throttled connection to the tank is opened.

The invention discloses a hydraulic control arrangement for controlling a number of consumers, particularly of a mobile working machine. In addition to the consumers of the control arrangement, an additional consumer should be able to be connected to a power beyond port. All consumers and power beyond consumers are supplied with hydraulic fluid by a pump. An input pressure scale is provided downstream of the pump, and the greater of the load pressures of the consumers or of the at least one power beyond consumer is applied to the control port of said input pressure scale.

Hydraulic control arrangement

What is disclosed is a hydraulic control arrangement for controlling a consumer, comprising a continuously adjustable directional control valve, an individual pressure compensator associated to the latter, as well as shut-off blocks arranged downstream from the directional control valve. In accordance with the invention, in the case of a insufficient supply of the consumer the pressure compensator is subjected not to the pressure in the supply (load pressure) but to a higher pressure, so that the control pressure difference at the supply control edge is raised.

What is disclosed is a hydraulic control arrangement for controlling a hydraulic consumer, comprising an adjustable supply measuring orifice and an adjustable drain measuring orifice as well as a pressure compensator arranged in a pressure medium delivery. The control arrangement moreover comprises a releasable cut-off block that acts as a check valve in the direction of supply and may be released in the direction of drain by means of a control pressure. In accordance with the invention, the pressure compensator is subjected to a constant force in the opening direction and to the lower one of the pressures downstream from the supply measuring orifice and upstream from the drain measuring orifice in the closing direction.

Growing community of inventors

Vaihingen, Germany

Heinrich Loedige