【正文】 velopment, in order to adapt to China in various fields used by the synchronous hydraulic lifting platform development needs and take the largescale, standardized , intensive, product support services, achieving mechanical, electrical, fluid integration platform in the application of synchronous movements. The use of synchronous hydraulic lifting platform surface, the service has been expanding, is now in rapid development stage, and now hydraulic lifting platform reliability, security, easy operation and simple directness, and other aspects greatly improved, and with the the popularity and development of puter and mechanical, electrical, fluid integration progress of the study, major domestic and foreign panies have to pete with the puter (electronic) control system to improve overall performance and reduce the use of hydraulic ponents, machine, reducing the whole size and weight, improve the sensitivity of control and synchronization accuracy. In particular, the manufacturers actively introducing and digesting foreign advanced technology, development of new varieties, improving product technology and quality level, has been part of the hydraulic lifting platform synchronized at or close to the international level of similar products. Currently used in the automotive repair Hydraulic synchronous lift platform vehicle maintenance plays an important role in synchronous lifting platform on a variety of hydraulic valves, hydraulic cylinders, hydraulic pump station innovation and improvement, making a hydraulic lifting platform synchronization Smooth running, low noise, fast response, high precision synchronization, for the repair and maintenance of the car plays an irreplaceable role in a wide range prospects. Therefore, the lifting platform for further research and improvement, optimize system performance and structure to further improve to make up for the shortings of existing technology has important significance. The subject of the design of the hydraulic lifting platform main use of theoretical research and design, through the understanding and study of the hydraulic system, as well as existing control technologies and more indepth research and development, in the hydraulic system ponents and further understanding and learning , Combined with the modernization of hydraulic ponents and automation and control ponents within the hydraulic control through traditional hightech ponents and control elements of existing parative and prehensive application of the traditional hydraulic system, based on the research and design more innovative set of machines , Electricity, liquid in one of the hydraulic control system, makes the system more stable and faster to achieve the advantages. Hydraulic lift platform system, requires the ability to achieve fourwheeled vehicles in a controlled synchronous lifting height lifting range, to achieve safe and reliable control of the two front, two rear, two revolvers, two rounds of synchronous lifting the right and to ensure synchronous movements accuracy. The hydraulic lift system also must have a fast response speed, hydraulic power units, small size, pact structure, large power weight ratio, ease of manipulation and control, laborsaving convenience and easy to implement automated, with overload protection for high reliability requirements system, excellent technical performance, while ensuring synchronous hydraulic lifting platform can be anywhere in the vertical direction on a longer time (60 min or longer) within a reliable locking, the system can work continuously and reliably, the system energy efficient, easy to maintain low cost. Hydraulic lift platform to meet system design requirements, synchronous movements smooth, and the design to achieve the functional requirements, develop the system closedloop control of hydraulic systems, hydraulic systems used to satisfy the synchronization requirements of precision and control to achieve the fourwheeled vehicles in a controlled synchronous lifting height lifting range, to achieve safe and reliable control of the two front, two rear, two revolvers, two rounds of synchronous lifting the right and to ensure the accuracy of synchronous movements. To meet the synchronous lifting hydraulic system, the system needs to have synchronization control device to achieve synchronization. Synchronization of hydraulic system is currently running multiple control methods, mainly mechanical synchronization method, pump or motor parallel method, double rod cylinder in series, control valve, synchronizer, synchronization control valve circuit, servo and so on. According to the design of machinery and equipment requirements for the realization of a better twocar frontwheel, two rear, two revolvers, two synchronous lifting the right wheel, respectively, the flexible control, the design of the four hydraulic cylinders used for its intended to achieve their respective parts of the wheel lift and flexible control. Synchronization to achieve higher accuracy and more flexible control, the design does not use the traditional control valves