3. When the relationship between the constant pilot pressure control and constant voltage control between the control priority to the pilot pressure control source hydraulic motor, the pilot pressure control and constant voltage control can not control the motor, the motor constant working pressure below the set pressure The motor will be fully provided by the pilot pressure control system; when the motor operating pressure reaches the set pressure constant, constant pressure control servo valve motor will be automatically controlled. Construction machinery often work in heat, dust, mud splashes, low or high temperatures and light radiation is very hostile environment, requiring hydraulic medium and long-term components work reliably in harsh environments. To this end the hydraulic motor maintenance, in addition to the traditional protection technology, developed a filter element from technology, new filters, hydraulic cylinders and other new materials. In order to prevent dirt from entering the system affect the reliability of the hydraulic motor repair, experts recommended on the tank bulkhead construction machinery hydraulic system of the installation of the filter back to the oil filter to remove impurities are not filtered; additionally provided an electromagnet in the tank to absorb iron. In order to improve the life of the hydraulic pump motor, some hydraulic system uses a pneumatic compression pump suction tank to improve conditions, to prevent the occurrence of cavitation. Currently, there are three commonly used methods of inflating for reference: ① machine using compressed air compressed air systems provide; ② rely on liquid thermal expansion of pressurized air above the liquid surface; ③ pump compressed air using the engine change. Hydraulic motors agents, crystal creating hydraulic assurance (certification), a hydraulic motor provided by the Jinan Jing Chong Hydraulic Machinery Co., Ltd .. Jinan Jing Chong Hydraulic Machinery Co., Ltd. (www.jnjcyy.com) (www.jnjcyy.com) Shandong Jinan, mining machinery leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, the maximum meet customer needs. In the crystal creating hydraulic leadership with the staff warmly welcome all inquiries negotiations to create the crystal creating hydraulic better future.