摘要:
The present invention relates to an electronically controlled valve for a variable displacement pump, a hydraulic pump and a hydraulic pump system with switchable control functions. Multiple control functions of different types of hydraulic pumps can be implemented via one single electronically controlled valve combined with control elements and sensors. The hydraulic pump systems can be easily integrated into the overall application systems for intelligent control.
摘要:
A hydraulic fan drive for a cooling system of an internal combustion engine, in particular a diesel engine of a mobile working machine or a construction machine, is configured to be switched off for a short time or by way of a transition in dependence on a load of the internal combustion engine. A shut-off valve, which is arranged in a working line connecting a variable-displacement pump to a fan motor, is configured to switch off the fan drive. The fan drive is further configured to be switched off by rotational speed monitoring of the internal combustion engine.
摘要:
A method for controlling a variable displacement pump by calculation by a controller using a closed-center-type directional control valve, the method allowing effective utilization of the variable displacement pump while avoiding the risk of engine stall is provided. The method includes determining a first virtual discharge pressure and a second virtual discharge pressure. The method includes controlling the variable displacement pump based on a smaller value of the first virtual discharge pressure and the second virtual discharge pressure.
摘要:
Proposed is a method for controlling pressure supplied by a hydraulic pump that includes determining whether there is an impending overshoot in a value of the pressure supplied by the hydraulic pump and engaging a peak and hold controller when it is determined that there is an impending overshoot in a value of the pressure supplied by the hydraulic pump, thereby reducing or eliminating supplied pressure overshoot.
摘要:
Provided is a driving device for a working machine, which can drive one or more hydraulic pumps in a large capacity range of as high efficiency as possible. In a driving device for a hydraulic excavator, a controller (41) is provided with a first target delivery-flow-rate setting unit (41a) that computes a first target delivery flow rate of pressure oil, which is to be delivered from at least one of variable displacement hydraulic pumps (2a-2f) to a hydraulic actuator, according to a lever stroke from one of control devices 40a,40b and corresponding one of preset efficiency values set beforehand for the hydraulic pumps.
摘要:
A system and method is provided for controlling a variable displacement piston pump that supplies fluid to one or more loads. If fluid is being supplied through a metering valve to a load, then the variable displacement piston pump is controlled to operate in accordance with a variable flow/variable discharge pressure scheme. However, if fluid is not being supplied through the metering valve to the load, then the variable displacement piston pump is controlled to operate in accordance with a variable flow/constant discharge pressure scheme.
摘要:
The invention relates to an electromagnet for actuating a valve. To this end, the electromagnet (28) comprises an armature (58), which can be axially displaced in an armature space (57, 77) and whose axial motion displaces a tappet (29) to the valve. The electromagnet is provided with reflux channel (71.1), which is connected to the armature space (57, 77) and via which the armature space (57, 77) is connected to a tank volume (25) in order to lead away a pressure medium leakage flow that is flowing out of the valve and into the armature space (57, 77).
摘要:
A flow control system for controlling a variable displacement pump including a metering valve in fluid communication with the pump for metering an output of the pump. A regulating valve receives a portion of the output of the pump as a bypass flow at a first pressure, wherein an output of the regulating valve is at an interim pressure. The interim pressure is substantially equal to an average of the first pressure and a low reference pressure. An actuator sets a displacement of the pump by acting on a piston connected to a cam ring of the pump. The actuator receives the interim pressure and, thereby, the output of the variable displacement pump is determined.
摘要:
A zeroing mechanism for a hydrostatic piston/cylinder unit (1), has an actuating piston (2) that can be moved from a zero position N into at least one deflected position A and can be returned to its zero position N by a zeroing force, the zeroing force being produced at least in part hydraulically.
摘要:
A hybrid or battery type working machine including a hydraulic pump, an electric motor, an electric storage device, and a control device which controls a pump absorption horsepower maximum value in accordance with an amount of electricity stored in the electric storage device. The control device reduces the pump absorption horsepower maximum value by dividing the pump absorption horsepower maximum value into a plurality of regions having different target flow rates, and reduces the pump absorption horsepower maximum value from an old pump absorption horsepower maximum value corresponding to the pump absorption horsepower maximum value which has not yet been reduced to a new pump absorption horsepower maximum value corresponding to the pump absorption horsepower maximum value which has been reduced, so that temporal differences among the regions can increase in a descending order of a target flow rate.