Power control valve and loader constant variable hydraulic system

Abstract

The invention relates to a loader quantitative-variable hydraulic system and aims to overcome the defect that the input power of a variable pump in the existing quantitative-variable hydraulic system accounts for a large amount. The invention further discloses a power control valve. A first cavity in a valve body is communicated with a port PLS and acts on the right end of a main valve element. A valve element spring is disposed at the left end of the main valve element. A valve sleeve sleeves the main valve element. A second cavity is communicated with a port P1 and acts on the right end of the valve sleeve. A third cavity is communicated with a port P and acts on the left end of the valve sleeve. A valve sleeve spring provides leftward elastic force for the valve sleeve. An oil drainage passage communicated with the third cavity and a port T are formed in the main valve element and the valve sleeve. When the main valve element moves leftwards relative to the valve sleeve, the oil drainage passage is communicated. When the main valve element moves leftwards relative to the main valve element, the oil drainage passage is reduced or closed. The power control valve has the advantages that the valve sleeve and the main valve element form a follow-up mechanism, the input power of the variable pump of the loader quantitative-variable hydraulic system can be controlled by the power control valve, and the input power is prevented from accounting for a large amount.

Description

technical field [0001] The invention relates to a loader hydraulic system, in particular to a power control valve used in a loader constant-displacement hydraulic system and a loader constant-displacement hydraulic system with the power control valve. Background technique [0002] At present, the commonly used loader hydraulic systems include quantitative hydraulic systems, fixed variable hydraulic systems and full variable hydraulic systems. The technical characteristics of each hydraulic system are as follows: [0003] The throttling loss, overflow loss, and loss along the way of the quantitative hydraulic system have large power losses and low energy conversion efficiency, but the system is simple in structure and low in cost; [0004] The full variable hydraulic system has no overflow loss, and the throttling loss and the loss along the process are the lowest, the energy conversion efficiency is high, and the energy saving effect is good, but the hydraulic components ar...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a loader in view of the shortcomings of the variable pump in the fixed variable hydraulic system of the existing loader that the input power of the pump accounts for a large proportion of the input power of the pump under heavy load due to the output of the rated displacement, which leads to insufficient power input of the walking system. Power control valve used in constant variable hydraulic system and loader constant variable hydraulic system with the power control valve

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