Method and control device for controlling a hydraulic consumer
AssigneeBosch Rexroth AG
InventorBurkhard Knoll
Life of this patent
Estimating the term…
Abstract
A method and a control arrangement for driving at least one hydraulic consumer are disclosed. The control arrangement comprises a pump whose output is adjustable as a function of the load pressure of a consumer. The consumer is driven through a proportional directional valve forming a measuring orifice, a pressure compensator being associated with the directional valve, allowing the pressure drop across the measuring orifice to be maintained constant irrespective of the load pressure. According to the invention, a low load pressure is indicated to the pump when the pressure compensator is completely open, so that the pressure drop across the measuring orifice is reduced.
Claims17
A method for driving a consumer through a control arrangement, comprising:
- controlling an output of a pump as a function of a load pressure in a load pressure channel, so that a pump pressure of the pump is maintained above the load pressure by a predetermined pressure differential;
- keeping a pressure drop across a measuring orifice constant, irrespective of the load pressure, wherein the measuring orifice is formed by a directional valve having a directional valve slide, in which a control piston of a pressure compensator is slidably mounted;
- applying pressure downstream of the measuring orifice to the control piston in an opening direction;
- applying the load pressure and the force of a control spring to the control piston in a closing direction;
- and
- indicating pressure downstream of the measuring orifice to the load pressure channel when the pressure compensator is completely open that is lower than the load pressure of the consumer by an amount that is less than the predetermined pressure differential.
A control system for driving at least one hydraulic consumer, comprising:
- a pump having an adjustable pressure, wherein the pressure is adjustable as a function of load pressure in a load pressure channel, such that the pump pressure is higher than the load pressure by a predetermined pressure differential;
- a measuring orifice formed by a directional valve having a directional valve slide, in which a control piston of a pressure compensator is slidably mounted, wherein a pressure drop across the measuring orifice may be maintained constant, irrespective of the load pressure, with pressure downstream of the measuring orifice being applied to the control piston in an opening direction and the load pressure and a control spring force are applied to the control piston in a closing direction;
- wherein a pressure may be indicated to the load pressure channel when the pressure compensator is completely open that indicates a load pressure that is reduced by less than the predetermined pressure differential, this reduced load pressure indication being controlled by dimensioning at least one of the spring constant and bias of the control spring.
Dependencies are inferred from the claim text.