Original AbstractHydraulic lifting platform is a versatile crane lifting equipment, widely used in factories, docks, construction, transportation, sports, equipment maintenance and other high-altitude operations and maintenance. Existing hydraulic lifting platform there are many, can be roughly divided into: four-wheel mobile lifting platform, push-type lift platform, car load lifting platform, fixed platform lift, scissor lift platform, four-post lift The two column lift and so on.In recent years, with the rapid increase in the use of cars, China's booming auto industry, especially the car industry. This makes the auto repair industry has grown, demand for automotive maintenance equipment rapid expansion, but also the maintenance requirements in the automotive tools and equipment requirements on the increasingly high lift vehicle repair workshop is essential and most important maintenance machinery and equipment. The role of auto lift car is in need of repair, a smooth upgrade to the appropriate height, so that maintenance workers at the bottom of the car chassis maintenance and inspection. Generally divided into high column car lift and scissors. Either way, are required to meet the synchronous lifting the car, cornering can not happen, and asked for the empty chassis bottom for easy maintenance workers for maintenance work which requires lifting platform synchronous lifting, running smoothly. Therefore, maintenance of the car lifting platform equipment is generally driven by hydraulic system.With the expanding service sector, as well as the further development of automation, the maintenance staff to reduce labor intensity, making the easy maintenance, and can better improve the efficiency of vehicle maintenance, and car maintenance service quality, so the hydraulic lift Platform automation requirements are also rising. Vehicle maintenance is currently required to meet the synchronization control, lifting the platform lift system depends mainly on the hydraulic system and electrical control and drive systems, but the lift platform is currently owned by the widespread leakage, internal leakage, short life, the operation not flexible, synchronous operation and low defects. To avoid these disadvantages, require more precise synchronization to ensure that the hydraulic lifting platform lift precision, and now most of the hydraulic lifting platform simultaneously phasing out all traditional hydraulic valves, the use of more precise control of the new electro-hydraulic servo valve, electro-hydraulic proportional digital electro-hydraulic valve and valve to control the hydraulic system, to achieve synchronization and high precision. As a form of electro-hydraulic proportional valve type of diverse, easy to use composition of a variety of electrical and computer-controlled hydraulic system, control of high precision, installation flexibility and strong anti-pollution and many other advantages.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 smoothrunning, low noise, fast response, high precision synchronization of the repair and maintenance in the car played a crucial role.With the hydraulic lift platform in the automotive repair industry, application and further improvement and innovation in the maintenance of hydraulic lifting platform has the car can achieve more complex functions, the structure of the platform, drive on, and a variety of control systems, has been greatly improved. The current lift platform lift system is mainly driven by the hydraulic system, of course, do not rely on hydraulic pressure, as well as dual-use diesel electric rotary lift platform, now appeared battery driven lift platform, continuously variable transmission can be achieved with safer, more convenient and low noise advantages. Lifting platform is currently widespread leakage, internal leakage, short life, the operation is not flexible, synchronous operation and low defects. To avoid these disadvantages, require more precise synchronization to ensure that the hydraulic lifting platform lift precision, and now most of the hydraulic lifting platform simultaneously phasing out all traditional hydraulic valves, the use of more precise control of the new electro-hydraulic servo valve, electro-hydraulic proportional digital electro-hydraulic valve and valve to control the hydraulic system, to achieve synchronization and high precision. As a form of electro-hydraulic proportional valve type of diverse, easy to use composition of a variety of electrical and computer-controlled hydraulic system, control of high precision, installation flexibility and strong anti-pollution and many other advantages, applications become increasingly broadened.In China, although synchronous hydraulic lifting platform for such development, production started late, but with China's rapid economic development, in order to adapt to China in various fields used by the synchronous hydraulic lifting platform development needs and take the large-scale, 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 computer and mechanical, electrical, fluid integration progress of the study, major domestic and foreign companies have to compete with the computer (electronic) control system to improve overall performance and reduce the use of hydraulic components, 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 shortcomings 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 in-depth research and development, in the hydraulic system components and further understanding and learning , Combined with the modernization of hydraulic components and automation and control components within the hydraulic control through traditional high-tech components and control elements of existing comparative and comprehensive 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 four-wheeled 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, compact structure, large power weight ratio, ease of manipulation and control, labor-saving 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 closed-loop control of hydraulic systems, hydraulic systems used to satisfy the synchronization requirements of precision and control to achieve the four-wheeled 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 two-car front-wheel, 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 to control, but intends to adopt more new electro-hydraulic proportional control valve to control. Electro-hydraulic proportional control valve is between the ordinary hydraulic valveand servo valve between a fluid control valves, servo valves with similar functions, but also has its specific advantages. Proportional solenoid valve is replaced by the proportion of ordinary hydraulic valve adjustment and control devices and form, it can be given input voltage or current signal proportional continuous, remote control of the direction of flow, pressure and flow. Reasonable use of electro-hydraulic proportional control valve can improve the automation and accuracy, and simplify the system. Commonly used proportional valve can be divided into: proportional pressure valve, proportional flow valves and proportional directional valve three.The design uses electro-hydraulic proportional control system, closed-loop feedback control system, the detection by the sensor and fed back through the electro-hydraulic proportional plc valve, electro-hydraulic proportional control valve opening size corresponding to the achievement of the hydraulic cylinder to achieve synchronous lifting control accuracy. To ensure the hydraulic cylinder to achieve at work to ensure self-locking, hydraulic system should be in each cylinder fuel supply system with check valve to achieve self-lock function to ensure the safety of hydraulic lifting platform. Overload protection to ensure the realization of the hydraulic system, hydraulic system relief valve in the hydraulic pump that needs to be installed to ensure the safety of the system to provide a certain pressure. Oil to the system to meet the system requirements to run and quality of hydraulic oil, hydraulic system should be in the inlet and outlet port to install filters. In order to meet the hydraulic system can be fully automated, the system of hydraulic directional control valve solenoid valve are used. In order to better respond to energy problems, you can, where necessary, instead of using the accumulator motor-driven pump provides the pressure accumulator to provide the direct use of the hydraulic cylinder pressure to meet the relevant sport.In order to achieve self-locking hydraulic cylinder to the function of the hydraulic system in the bottom of each cylinder are equipped with check valve, check valve can achieve one-way self-locking, two-way communication function of the oil. In order to provide security to meet the hydraulic system pressure, not suddenly as high pressure hydraulic system of the adverse effects or even damage some of the hydraulic components, so as a safety valve with pressure relief valve to prevent hydraulic overload protection. In order to achieve automation of the hydraulic system to meet the simultaneous operation of the system is more accurate, and the realization of the system's high efficiency, rapid response requirements, the use of electro-hydraulic proportional directional control valve to high precision, fast response to the synchronization control. Most of the traditional manual control valve, which controlled comparison machinery, it is difficult to achieve automation. Electromagnetic valve, use the pull solenoid valve to control the direction of control of the commutation circuit to achieve better automated results. Shunt valve assembly, also known as synchronous valve, is a hydraulic diversion valve, valve functions in one set of the independent hydraulic device. Shunt valve synchronization is the set speed sync, that is, when two or more cylinders cylinder under different loads, respectively, the shunt valve set pressure and flow through the sensitive internal components automatically adjust the fuel tank of exercise to maintain synchronization.Shunt valve assembly is mainly used in multi-cylinder hydraulic cylinder and the synchronization control system. Split set by the synchronous control flow valve hydraulic system has a simple structure, low cost, design, sets, debugging and ease of use, reliability and many other advantages, which shunt valve assembly in the hydraulic system has been widely used, so there will also be a reasonable set of flow diversion valve used to achieve simultaneous control of two hydraulic cylinders. In the hydraulic system, the oil cleanliness of the normal operation of the hydraulic system has a vital role, so the oil pump and fuel tank return port port filters have been installed in order to ensure that the cleaning fluid degrees, which is an indispensable circuit hydraulic system attachment.In this system, due to the beneficial effects of gravity, the decline in the course of lifting platform, you can completely rely on gravity to provide power, where only one-way valve on the hydraulic control valve port for remote control of the pressure to provide, in under the action of gravity to allow check valve can be decreased to achieve oil return channel, as the pressure is not big, so no need to re-use of oil pump drive motors to achieve the check valve through the oil pressure can be used directly to provide the pressure accumulator, so the treatment, not only simplifies the system control, and can better save energy and avoid frequent start the motor, can effectively extend the life of the motor and pump, and to improve the efficient use of the hydraulic system, which can be said that the biggest advantage of the system design.Hydraulic platform of exercise is to achieve the various hydraulic cylinders rise and fall, but the rise and fall during the lifting phase will be a period in the acceleration of movement, until the required speed to the speed, the platform will achieve a uniform motion and then decelerate to stop. Throughout the campaign process, the hydraulic lifting platform mainly by the external load platform of the car's own weight of gravity and composition. Therefore, the size of the external load is relatively stable and unchanging, and only in the acceleration phase of operation of the entire platform will have a maximum load.Hydraulic lifting platform synchronized variety of mechanical structure, a four-wheel mobile lifting platform, elevating platform vehicle-mounted, fixed landing platform, sets of cylinder-type lift platform, four-column lifting platform, the two-column lifting platform, scissor Lifting platform, and other mechanical structure, and mechanical structure of different ways to achieve different movements to meet the different, specific ways of working and working environment.The design of synchronous hydraulic lifting platform is designed to meet the car repair industry in the use of lifting platform. Maintenance workers to consider maintenance when the car convenient and comfortable, you need to lift the car a certain height, but such use conditions, most of the requirements of hydraulic lifting platform is fixed, so the fixed hydraulic lift platform. While the four cylinder design can be fixed in the foundation, and to consider their own characteristics and the hydraulic cylinder the height, you can dig a pit in the maintenance shop type of foundation, the four cylinder bolts to fully firmly fixed to the ground by on. In order to be able to check and repair chassis, hydraulic lifting platform not designed for the whole plate fixed on the hydraulic cylinder in the bottom four shelves, is thoughtful, Idesigned the mechanical structure to meet the four-wheel placed in the middle hollow of the platform structure, so that not only meet the maintenance requirements, but also save a portion of material, making the structure more simple and beautiful. Taking into account the car body as a whole if there is a need to use floating platform from the condition, for example, remove the wheels need repair or need to dress up tires, etc., are required to meet all hold up the whole body, this, this design in each set of two plates of another set of lifting devices, lifting devices to facilitate use of the vehicle chassis will hold up, to achieve overall body vacant. To consider the overall open on the car platform, hold up the car fixed and plate lifting devices, and can be used scissor lift to reach the level of a structure. The biggest advantage of using this structure is not hold up in the chassis to the plate when retracted within this structure, so that the overall structure is beautiful and practical. To meet the car on the platform do not slip and stable place on the platform, placed on the plate anti-slip skid plate.Programmable Logic Controller (PLC) is an industrial control computer, is the succession of computer, automatic control technology and communication technology as one of the new automatic device. It has strong anti-interference ability, low price, reliability, programming is simple, easy to use and so on, in the industrial field operators by the likes of engineering, so PLC in all areas of industrial control is widely used.The design is based on the ratio of the hydraulic cylinder piston rod valve position control system, namely the use of PLC control signal generated by electro-hydraulic proportional valve driver to control the exact location of the hydraulic cylinder. Hydraulic cylinder piston rod displacement sensor displacement feedback signal output by the A / D converted into digital signals into the computer, the PLC signals within a given comparison, and the control algorithm according to the set after the output control signal, after D / A converted to analog voltage or current signal proportional electro-hydraulic control valve spool position to control the flow of the hydraulic cylinder transmission, drive hydraulic cylinder, to achieve the position of the piston with a load control system as a whole constitute a closed-loop control for precise positioning .原文摘要液压升降平台是一种多功能起重升降设备，广泛应用于工厂、码头、建筑、交通、体育馆、设备检修等高空作业及维修。
