| With several times speed raises, China railway has brought itself in line with international railway practice nowadays. The designed maximum speed of dedicated passenger railway lines is to reach 350km/h, and the bridge has changed accordingly to meet demand of high speed and heavy load service, for instance the single-duct girder mass is about 850 ton. Therefore ordinary bridge can not meet the construction requirements, and the paper has finished the design of JQ900C bridge girder erecting machine. The main work and result is shown as follow.The paper has put forward a overall scheme of JQ900C bridge girder erection machine, includes structure version, hydraulic system and electrical system. The system reliability design, work program module and so on perform the bridging function.Of the whole structure, main work is taken on the design and introduction of the lifting crane, main girder, rear and front support frame and guide girder. Highlight of the creative feature is the simple through span girder which has high safety performance, and lower mass of itself compared with other like types. With tyre running, low gravity center and few auxiliary operations, it is a low cost but high efficiency product.The hydraulic system has seven independent subsystem, each has its own pump. The electromagnetic directional valves control every execute component. The rear support frame is hybrid hydraulic system, namely close loop moving system. Other systems equipped with open loop system to control execute component. Each system has oil stopcock, oil quantity indicator, oil press indicator and protective function.The electrical system adopts control net-DCS. With PLC as its inner core, the whole net composes the device level, control level and management level to meet the safety, reliability and convenience requirements of bridge girder erecting... |
