Energy-saving type prior unloading valve

Abstract

The invention discloses an energy-saving type prior unloading valve which belongs to the technical field of hydraulic steering systems of engineering machinery. The energy-saving type prior unloading valve comprises a valve body, a prior valve core, a sliding valve, an unloading valve core and an LS control plug screw, wherein an oil channel CF, an oil channel P, an oil channel P2, an oil channel P1 and a return oil channel T1 are formed in a valve hole of the prior valve core; and the oil channel P2, a return oil channel T, an oil channel LS and an unloading safety valve guide return oil channel T2 are formed in a valve hole of the unloading valve core. A load sensing complete hydraulic steering hydraulic system is formed by the energy-saving type prior unloading valve together with a load sensing steering gear and a steering pump, the sliding valve is additionally arranged, and the movement of the sliding valve is controlled through the pressure of the steering gear LS, so that the divided and combined flow high/low pressure control is realized, and the steering prior is ensured; and when a loader is not steered, steering pump hydraulic oil is subjected to prior valve flow combination or load oil returning under the lower pressure, so that the pressure loss of the steering pump combination or the load oil returning in the working condition that the loader is not steered is reduced, the unnecessary energy loss of the system is reduced to the maximum extent, the oil temperature is lowered, and the energy saving effect is effectively achieved.

Description

technical field [0001] The invention belongs to the technical field of hydraulic steering systems of engineering machinery, and in particular relates to an energy-saving priority unloading valve of a load sensing full hydraulic steering hydraulic system of a loader. Background technique [0002] At present, most domestic construction machinery such as loaders use a combination of steering pump, priority valve and load sensing full hydraulic steering system for their load sensing full hydraulic steering systems. The combination of sensing full hydraulic steering gear has obvious energy-saving effect, but no matter which combination, in the process of non-steering and merging, the steering pump oil is all merged into the working system or unloaded and returned to the oil, it is necessary to overcome the spring of the priority valve The peak pressure of the priority valve control pressure can reach about 1.5MPa, and there is always a power loss of about 3KW, resulting in an inc...

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Problems solved by technology

[0003] The application of energy-saving hydraulic components on loaders is a development trend, and it is also the current domestic demand for the green revolution of modern construction machinery such as loaders. Variable steering hydraulic systems are currently not available in China due to high manufacturing costs and maintenance costs. Fast application, the popularization rate of existing mainstream manufacturers is not high, and it is basically in the research stage. Improving the pressure loss problem existing in the existing quantitative steering hydraulic system and improving the reliability of existing products are also urgent tasks

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