Hydraulic technology is one of the key technologies for the modern mechanical drive and control. The development of homemade advanced high quality construction machinery is limited for that there is no homemade key hydraulic parts. At present, the homemade hydraulic parts is mainly the gear pump, cylinder, and main valve of under 16 MPa, which can only be used at loaders, forklift trucks, and bulldozers. During the application of high pressure variable system (21~45MPa) on excavators, skid steer loaders, road machinery, concrete machinery, piling machinery, mining machines, etc. there is little homemade products. Currently, the homemade medium/advanced construction machinery all adopt imported hydraulic parts (mainly from Japan, Germany, and America). The development of homemade heavy equipment and military equipment are limited by the hydraulic system due to the restriction by foreign suppliers with high price, long delivery period, and small supply, etc.

To meet the demand for machinery products due to the development of national economy and the key construction projects, the key hydraulic parts has been selected as the priority project for scientific product development, which is proposed by Ministry of Industry and Information technology of P.R.C.