One-way high-pressure limiting valve

Abstract

A high pressure pressure-limiting check valve is used in a hydraulic unipump of agricultural machinery, realizing going forward, drawing back, stop and speed changing. The invention includes a pump cover body, a valve stem, a big spring, a small spring, an axle sleeve and a nut. The valve stem drills through the center hole of a valve seat and the axle sleeve. One end of the big spring is sheathed on the valve seat and the other end is sheathed on the axle sleeve. The nut is connected with the valve stem. The invention is characterized in that the external circumference of the valve stem and the hole of the valve seat adopt an exact dynamic fit. The joint of the left end of the valve stem extending out of the valve seat hole and the valve seat adopts the linear seal. The seal face of the valve stem is a sphere surface. A steel sleeve is arranged inside the valve opening of the pump cover body. The joint of the steel sleeve and the valve seat also adopts the linear seal. The seal face of the valve seat is also sphere surface. The external circumference of the vale seat and the axle sleeve and the valve opening of the pump cover body adopt a clearance fit. The invention has the advantages of good seal performance, stable pressure, low noise and safe operation. The invention improves the on-off characteristic, consequently improving the efficiency and the operational reliability of the agricultural machinery.

Description

technical field [0001] The invention relates to the technical field of hydraulic valves, in particular to a combined valve of a safety valve and a check valve in a combined hydraulic pump. Background technique [0002] Rice combine harvesters and other agricultural machinery mostly use hydraulic combination pumps to achieve forward, backward, stop and speed change control. Among them, the one-way high-pressure pressure limiting valve is an important component of the hydraulic combination pump. It has a one-way valve and a safety valve. Two functions; the one-way high-pressure pressure-limiting valve is located in the pump cover body of the hydraulic combined pump. Flow; the one-way high-pressure pressure limiting valve in the current hydraulic combined pump includes the pump cover body, the valve seat set in the valve hole of the pump cover body, the valve stem, the spring, the bushing, and the nut, wherein the valve stem freely passes through the valve seat The center hole...

AI Technical Summary

Problems solved by technology

[0002] Rice combine harvesters and other agricultural machinery mostly use hydraulic combination pumps to achieve forward, backward, stop and speed change control. Among them, the one-way high-pressure pressure limiting valve is an important component of the hydraulic combination pump. It has a one-way valve and a safety valve. Two functions; the one-way high-pressure pressure-limiting valve is located in the pump cover body of the hydraulic combined pump. Flow; the one-way high-pressure pressure limiting valve in the current hydraulic combined pump includes the pump cover body, the valve seat set in the valve hole of the pump cover body, the valve stem, the spring, the bushing, and the nut, wherein the valve stem freely passes through the valve seat The center hole, the valve port is sealed with a tapered surface, one end of the spring is sleeved on the valve seat, the other end is sleeved on the shaft sleeve, the shaft sleeve and the valve stem are connected by threads, and the pressing force of the spring can be changed by rotating the shaft sleeve; The structure can control the walking operation of the machine, but there are still some problems in the following aspects: First, there is no guide device between the valve stem and the center hole of the valve seat, and the length L of the spring and the middle diameter d of the spring 2 The ratio is greater than 3, according to the principle of mechanical design, when the spring L:d 2 When >3, it is necessary to add a guide device. Since there is no guide device, the spring is easy to bend axially, causing the valve seat, bushing and valve hole to be stuck. It is easy to generate noise; the third is that the sealing surface of the valve stem is tapered, the sealing is unreliable, and the opening and closing characteristics are poor; resulting in unreliable use, the maximum torque and maximum speed of the output shaft are reduced

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