| Crawler crane is mobile crane crawler device, lifting operation part into crawler chassis, walking on the crawler attachment, which can undertake material lifting, transportation, loading and unloading, installation and so on. It has so many advantages, such as small size in grounding and turning radius, adapting to bad floor, good capacity in climbing and lifting, hanging heavy load without hitting a leg, driving with some special devices to become grab crane, electromagnetic crane or hammers, which widely uses in electric power construction, dredging operations, municipal construction, bridge construction, petrochemical industry, water conservancy and hydropower industries. Because of the load of driving and lifting arm long combination good performance, Crawler crane has its unique incomparable advantages. Nowadays, with the rapid development of our economy, the scale of the national construction is much more larger than before, the need of the quality, height and volume of the item hoisting is much more bigger, so crawler crane rapidly shows its superiority and market capacity rising, which attracts the attention of international well-known manufacturers, domestics crane industry and arises crawler crane development.It expounded the transmission way, principle and application of hydraulic transmission technology, based on the analysis of crawler crane composition, working principle, characteristics and structure of walking system. It also established the dynamic mathematical model, got input/output transfer function according to the digital analysis of walking crawler crane hydraulic components. Adopting 100t Li Shi Le system as simulation object and according to the main parameters hydraulic components , it established the intuitive physical model AMESim.In Li Shi Le system, we adopted multi-channel valves system which is characterized by proportional control, two pump control according to the power, hydraulic linked, three positions and six channels, without power overreaching. The flow of two pumps could change alone according to their own load, this system′s load adaptive is superior to that of the whole power system. Because of pressure loss, single pump absorbs the motor power partly, working ability of the system is limited. Based on the crane using this system nowadays, with intention to make it work perfectly, this paper draws conclusions under the results got from detections and simulations:(1) Flow is irrelevant with load pressure, it directly decided by the size of valve opening, indirectly by the pump displacement of system and the engine speed, the flow is basically limited when the valve opening is fixed. When we need fixed flow under low engine speed, we should increase the pump displacement which is provided to the proportional valve in order to maintain large flow. The pump displacement is large at low speed, so system need larger drive torque.(2) Crawler crane is an equipment drived by much load at the same time, when applying load sensing technology to it, the hydraulic pump's LS feedback pressure reflected the maximum load, so the pressure loss in low-voltage is larger.(3) With the crane speeds of 700r/min and 1900r/min and different walking stations, based on the pressure produced from the control mouths of walk valve, pump, load feedback and others, we can get the position and cause reason of the pressure loss which come from the pressure gap formatted when the oil flow through the balancing valve and one-way valve, there are also pressure loss in pipes, multi-channel valve and center axially symmetrical. There are pressure losses at every parts in walking system, and the loss in pipe does not match the valve. To change the smaller diameter of pipe in multi-channel valve and larger pressure loss, there are some advises that could effectively reduce the loss , improve the application of system power, and well protect the engine, they are increasing the channel diameters of motor balancing valve, pipes linked the pump export and entrance of multi-channel valve, introducing speed signal of engine to match motivation adaptability. It shows that the dynamic graphs got from simulation are anastomosis with those got from experiments, so the simulated results of walking drive hydraulic system can be basis of designing and improvement of hydraulic crawler cranes, also be the reference of building other hydraulic system in engineering mechanical.
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