Pressurization prevention multistage oil cylinder

Abstract

A pressurization prevention multistage oil cylinder comprises an outer cylinder barrel, a piston rod and one or more middle cylinder barrels sequentially arranged between the outer cylinder barrel and the piston rod in a sleeving mode, and the outer wall of the piston rod and the outer wall of the bottom end of each stage of middle cylinder barrel are sleeved with annular pistons. Each piston is provided with a decompressor. Each decompressor comprises a valve seat, a valve element, a spring and a valve sleeve. A first oil hole communicated with a rodless cavity and an axial mounting through hole is formed in each valve seat. Each valve element is of a stepped shaft structure, the small-diameter section of each valve element is close to the corresponding valve seat, the outer wall of the large-diameter section of each valve element is matched with the wall of the corresponding axial mounting hole, a pushing cavity is formed between the small-diameter section of each valve element, the wall of the corresponding axial mounting hole, the corresponding valve seat and the large-diameter section of each valve element, and a second oil hole is formed in each piston. According to the pressurization prevention multistage oil cylinder, when the supercharge pressure of a rod cavity reaches a certain value, oil in the rod cavity flows to the rodless cavity through the second oil holes, the pushing cavities and the first oil holes, and the pressurization effect problem of the rod cavity is solved effectively, and cylinder expansion accidents are avoided.

Description

technical field [0001] The invention relates to an anti-pressurization multi-stage oil cylinder. Background technique [0002] The multi-stage oil cylinder is made up of multiple piston hydraulic cylinders, and the cylinder barrel of the latter piston cylinder is equivalent to the piston rod of the previous piston cylinder. When the pressure oil enters the rodless chamber, the cylinder with the largest effective area of ​​the piston begins to protrude, and when it reaches the end, the cylinder with the second largest effective area of ​​the piston begins to protrude, so a long working stroke can be obtained, while the protruding The smaller the effective area of ​​the cylinder, the faster the extension speed, and the corresponding hydraulic thrust will change from large to small. This change rule of thrust and speed is in line with the operation requirements of most working machines, so this kind of oil cylinder is widely used in the fields of sanitation and mining. [000...

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Problems solved by technology

[0003] During the use of multi-stage oil cylinders, due to the lag of the system response speed, it is easy to cause the oil passage in the rod chamber to be blocked. In the event of jamming, etc., if the oil return path of the rod cavity is blocked, because the two ends of the piston must achieve a force balance, and the effective area of ​​the rodless cavity of the multi-stage cylinder is always greater than the effective area of ​​the rod cavity, therefore, in many There will be a supercharging effect in the rod chamber of the first-stage oil cylinder, and once the supercharging pressure exceeds the yield strength of the cylinder, the cylinder will undergo plastic deformation and a cylinder expansion accident will occur

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