Secondary stretching and retracting hydraulic cylinder and hydraulic equipment

Abstract

The invention discloses a secondary stretching and retracting hydraulic cylinder. The secondary stretching and retracting hydraulic cylinder comprise an outer cylinder barrel (1), a piston rod (3) with a piston and a middle cylinder barrel (2), wherein the outer end of the piston rod is provided with a first oil port (A), a second oil port (B), and a third oil port (C); a first oil channel (A1), a second oil channel (B1) and a third oil channel (C1) which are sealed relative to one another are formed in the piston rod; a first communication oil channel (13) and a second communication oil channel (14) are formed between a rod-free cavity of the middle cylinder barrel and a rod-free cavity of an outer cylinder barrel; the first communication oil channel is provided with a sequence valve (4); and the second communication oil channel is provided with a check valve (6). Moreover, the invention also provides hydraulic equipment with the secondary stretching and retracting hydraulic cylinder. The secondary stretching and retracting hydraulic cylinder and the hydraulic equipment can realize accurate sequential actions, and stretching and retracting of each stage can be independently controlled so as to meet the requirement of a complex mechanism; and the secondary stretching and retracting hydraulic cylinder works reliably, and is long in service life and high in safety.

Description

technical field [0001] The invention relates to a hydraulic cylinder, in particular to a two-stage telescopic hydraulic cylinder. In addition, the present invention also relates to a hydraulic device with the two-stage telescopic hydraulic cylinder. Background technique [0002] The two-stage telescopic hydraulic cylinder is a kind of hydraulic cylinder with a wide application range among multi-stage hydraulic cylinders. The so-called multi-stage hydraulic cylinder refers to a hydraulic cylinder that can achieve two or more levels of expansion and contraction. Those skilled in the art also call it a telescopic hydraulic cylinder, which generally includes an outer cylinder and at least one intermediate cylinder (also known as " "secondary cylinder" or "secondary piston") and piston rod (because the piston rod is often formed in a hollow form to set the corresponding oil pipe or as an oil inlet and outlet passage, so those skilled in the art also call the piston rod "the last...

AI Technical Summary

Problems solved by technology

During the movement of the hydraulic cylinder, the sealing ring of the piston rod of the hydraulic cylinder needs to pass through the oil hole C, and the sealing ring is easily scratched, which affects the service life of the sealing ring, resulting in poor reliability of the hydraulic cylinder

Specifically, the disadvantages of the two-stage telescopic double-acting hydraulic cylinder are: first, it can generally only bear a single load, which cannot meet the requirements of complex mechanisms

In fact, each stage of the two-stage telescopic hydraulic cylinder cannot achieve precise sequence control, and each stage of telescopic movement cannot be controlled independently; second, during the movement of the hydraulic cylinder, the piston rod sealing ring of the hydraulic cylinder needs to The oil hole and the sealing ring are easy to scratch, which affects the service life of the sealing ring, resulting in poor reliability of the hydraulic cylinder

Third, the layout of the oil circuit is relatively complicated, the manufacturing process is difficult, and the reliability is poor; fourth, the area ratio of the rodless chamber to the rod chamber is large, and since the corresponding sealing ring must pass through the oil hole, in order to prevent excessive damage to the sealing ring, the oil hole is generally Smaller design, which results in high resistance and slow return stroke

Fifth, because the two-stage telescopic hydraulic cylinder cannot reliably achieve sequential control, it is prone to failure during use, resulting in failure to work. For example, the hydraulic cylinder is disturbed for some reason, causing the oil passage or oil hole to be blocked. If it is blocked, this will cause the hydraulic cylinder to fail to move, and even cause some cylinders to be damaged due to excessive pressure

Images