The hydraulic system that has obtained the invention patent is upgraded from the traditional open hydraulic system to a closed hydraulic system, and the respirator that exchanges the oil tank with air is removed, and the entire oil tank system adopts a closed structure. Avoid water vapor and tiny particles in the air from entering the hydraulic system. At the same time, the entire hydraulic system is equipped with three sets of high-precision filtration systems, which makes the hydraulic system cleaner as it is used, and the probability of hydraulic system valve stuck and wear is greatly reduced, and the service life of hydraulic oil is greatly improved. improve.