An overflow valve for a pilot pump

Abstract

Disclosed is an overflow valve for a pilot pump. The overflow valve for the pilot pump comprises a bush, a valve element, a spring and a valve sleeve. An annular groove is formed in the left end of the large cylinder on the head portion of the valve element, wherein the diameter of the annular groove is phi C, and the depth of the annular groove is L. V-shaped grooves are evenly distributed in the surface of the large cylinder on the head portion of the valve element. Clearance fit with two different numerical values is adopted by matching between the surface of the cylinder on the tail portion of the valve element and an inner hole of the valve sleeve. According to the overflow valve, due to the fact that the annular groove is formed in the left end of the large cylinder on the head portion of the valve element, wherein the diameter of the annular groove is phi C, and the depth of the annular groove is L, the opening and closing characteristic of the overflow valve is improved, the quantity of leakage in the closing process is reduced, and the working efficiency is improved. The eight V-shaped grooves with the 60-degree included angles are evenly distributed in the surface of the large cylinder on the head portion of the valve element so that the overflowing stability can be improved, and vibration and swing can be avoided. Clearance fit with two different numerical values is adopted by matching between the cylinder on the tail portion of the valve element and the hole of the valve sleeve, the sealing performance of the portion with the diameter phi A needs to be good, the designed clearance value is small, the clearance value of the portion with the diameter phi B is large, and therefore the situation that the quantity of leakage in the closing process of the overflow valve is small is guaranteed, and the problem that a pilot pump vibrates and swings when an overflow valve is completely opened is solved.

Description

technical field [0001] The invention relates to a relief valve for a pilot pump. The relief valve is mainly used in the pilot oil supply system of a loader or an excavator. On the one hand, it ensures that the pilot pump can supply oil to the pilot valve in time and effectively. On the one hand, it protects the pilot hydraulic system. Background technique [0002] like figure 1 Shown is the basic structural diagram of the pilot pump relief valve, mainly composed of bushing 2, valve core 3, spring 4, valve sleeve 5, pressure regulating screw 6, O-ring 7, lock nut 8, etc. The above parts are collectively installed in the pump body 1 of the pilot pump. Its hydraulic schematic diagram is as follows Figure 4 As shown, when the pilot valve is working, the pilot pump supplies oil to it, and the relief valve is closed; when the pilot valve is not working, the relief valve is opened to drain the pressure oil of the pilot pump. There are two problems in the prior art: one is the ...

AI Technical Summary

Problems solved by technology

There are two problems in the prior art: one is the low closing efficiency of the relief valve, resulting in a large amount of leakage, which makes the oil supply of the pilot valve insufficient and affects its working efficiency; When it is drained, it will often produce vibration, which will cause the pilot pump to vibrate, which not only affects the normal operation of the pilot pump, but also greatly reduces the service life of the pilot pump

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