Load-sensitive control system, control method and hydraulic system

Abstract

The invention discloses a load-sensitive control system, a control method and a hydraulic system, and relates to the field of engineering machinery. The load-sensitive control system, the control method and the hydraulic system are used for achieving self-adaptive matching of system pressure and load pressure. The load-sensitive control system comprises a variable pump, a load-feedback oil circuit and a differential pressure control valve; the differential pressure control valve is connected with the variable pump and the load-feedback oil circuit, and the differential pressure control valve can enable a difference value between pressure of an outlet of the variable pump and pressure of a load on the load-feedback oil circuit to be changeable. According to the technical scheme, the load-sensitive system with the differential pressure changeable is provided, the system can eliminate the flow saturation phenomenon occurring in the idle-speed operation process of an engine and improve the speed regulating characteristic of the load-sensitive system, and meanwhile the energy-saving property of the system is improved.

Description

technical field [0001] The invention relates to the field of engineering machinery, in particular to a load sensitive control system, a control method and a hydraulic system. Background technique [0002] The load sensing system has good energy-saving characteristics and stability, and has been widely used in the crane hydraulic system. At present, the variable pressure pump load sensitive system of domestic and foreign manufacturers generally uses the method of constant pressure difference control. [0003] Variable pump: According to a certain control strategy, the displacement of the oil pump can be changed, generally a plunger pump. [0004] Variable pump load sensing system: The system can sense the pressure and flow demand of the actuator through the load feedback oil circuit, and feed back the pressure signal to the control mechanism of the variable pump, so that it can automatically adjust the displacement and pressure of the variable pump, and always match the load...

AI Technical Summary

Problems solved by technology

[0007] The inventor finds that there are at least the following problems in the prior art: see figure 1 , using the method of constant pressure difference control, in order to meet the pressure difference required by the system at the highest engine speed flow, it is necessary to set the ΔP value higher, otherwise the system flow will not increase

However, when the engine is idling, due to the high pressure difference of ΔP, when the handle is turned to half cavity, the variable displacement pump has reached the maximum displacement.

Continue to pull the handle in a large range, the handle control pressure changes, but the system flow does not change, making the handle control range narrow, there is a large idle stroke, which affects the speed regulation of the system

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