Metering valve

Abstract

The invention provides a metering valve which comprises a valve core arranged in a valve body, a metering sleeve, a center valve rod and a spring, wherein two groups of sealing elements and sealing working surfaces are formed between the metering sleeve and the center valve rod and can be sealed, a metering chamber is defined by the two sealing elements as well as the internal surface of the metering sleeve and the external surface of the metering sleeve between the two sealing elements, and each sealing working surface is composed of a cylindrical seal surface, a transitional surface and a non-seal surface, during the process that the sealing elements and the sealing working surfaces slide relative to each other so as to realize seal or detach seal, the sealing working surfaces do not cut the sealing elements; and in addition, the spring with appropriate fatigue strength appropriate is selected according to the actual stress in operation. Therefore, in the metering valve provided by the invention, the sealing elements and the spring are not easy to damage or lapse, thus the metering valve has the advantage of longer service life.

Description

technical field [0001] The invention relates to the technical field of valves, in particular to a quantitative valve for controlling a fluid source to quantitatively release fluid outward. Background technique [0002] Quantitative valve is a special valve that can precisely control the flow rate released by the fluid source each time. Quantitative valves are widely used in daily life. For example, common sprays, fuel-type nail guns and other products are equipped with quantitative valves. [0003] see figure 1 , which shows a quantitative valve used in a fuel nail gun provided by the US Patent No. US6302297 named "External metering valve for a fuel cell". The quantitative valve includes a valve body 16 , a valve core 32 , a spring 40 , a seal 46 and a seal 44 arranged in the valve body 16 . Wherein, the fuel tank 12 is connected to the lower end of the valve body 16 and communicates with the spring chamber 29 and the quantitative chamber 30 inside the valve body 16 . Th...

AI Technical Summary

Problems solved by technology

However, when assembling the spring, the optional size of the outer diameter of the spring is severely limited due to the need for the spring to pass through the quantitative chamber. When selecting the spring, it is necessary to have sufficient rigidity and strict The size of the spring is carefully controlled, resulting in the final selected spring with a small outer diameter but strong stiffness. Since the spring is always working under a stress higher than its own fatigue strength, the fatigue life of the spring is severely limited

When the spring is close to its fatigue life, it will not be able to quickly reset the spool, and at this time, the quantitative valve will fail

It can be seen that the quantitative valve provided by the above-mentioned prior art has the disadvantage that the service life of the valve is too short because the fatigue strength of the spring cannot meet the stress demand.

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