Analysis of Development Direction of Domestic Cranes

(1) Improving the structure of hoisting machinery and reducing its own weight Domestic cranes have mostly adopted computer optimization design to improve the technical performance of the whole machine and reduce its own weight, and adopt new structures as far as possible under this premise. For example, a half-detour main beam structure is used in the 5 to 50t general-purpose bridge crane. Compared with the normal box beam, the small stiffened plate in the main beam can be reduced or eliminated, the short stiffened plate can be eliminated, and the structural weight can be saved. Processing hours. At present, the National Spark Plan proposes that the bridge adopts four separate unequal height structures so that when it is at the same height as an ordinary bridge crane, the height of the bovine leg of the factory can be lowered by 1.5m; the ends of the two main beams are placed On the end beams, they are connected with high-strength bolts; as a result, the height of the wheel treads is reduced and the elevation of the factory's bovine leg is reduced. Under the effect of vertical wheel pressure, the column's calculation height is reduced, which reduces the cost of plant infrastructure and increases the life of the plant.

(2) Towards large-scale development Due to the importance and funding of the State-Guangxi source, many large and medium-sized hydropower stations have been built, and generating units have become larger and larger. In particular, the construction of the Three Gorges Project has rapidly increased the demand for large cranes. Two 1200/125t bridge cranes are installed in the main plant of the left bank of the Three Gorges Project and are equipped with 2000t large tower cranes. There are many large and medium-sized hydropower stations currently under construction, such as Yantan in Guangxi, Longtan, Geheyan in Qingjiang, and Shuikou hydropower station in Fujian; there are many nuclear power plants and large and medium-sized thermal power plants that need to be built. Large tonnage can be expected. The demand for high-performance cranes is very large and has broad prospects.

(3) Full use of foreign advanced technology The cranes and small-sized vehicles operating mechanism adopts the German “triple” drive device of demag, which hangs on the inner side of the end beam to prevent it from being affected by the understeer and vibration of the main beam. The performance and life of the operating mechanism, and the compact structure, beautiful appearance, easy installation and maintenance. With the improvement of domestic machining capacity, it is possible to make boring of the end beams of the cart and the trolley frame as a whole. Therefore, a 45-degree split and a wheel set or a cylindrical bearing box may be used instead of the angular bearing box and mounted on the axle of the wheel. The centerline of the axle hole on the wheel and the centerline of the end-beam form a standard 90 degree, so the horizontal and vertical deflection of the wheel can be strictly controlled within the specified range, so as to avoid the occurrence of the snaking track phenomenon. Since the small frame is formed by one boring after welding, the centerlines of the four wheel holes are in the same plane, so the problem of landing at three points is solved successfully.

The hoisting mechanism adopts a gear reducer with medium hard tooth surface or hardened tooth surface. The gear precision reaches level 7, and the tooth surface hardness reaches 320 HBS, which improves the carrying capacity and prolongs the service life. Electrical control has absorbed foreign advanced technologies and adopted a novel energy-saving speed control system. Such as thyristor cascade open-loop or closed-loop system, adjustment ratio up to 1:30. With the increase in speed requirements, variable frequency speed control systems will also be used on cranes. At the same time, the microcomputer control will also be applied to cranes. For example, the 600t dam gantry crane of the Three Gorges Project requires the use of a variable frequency speed control system, automatic microcomputer correction, and a high-precision high-precision microcomputer monitoring system. With the increase in demand for production and development of remote-controlled cranes, Baosteel has made recommendations for the development of remote-controlled cranes after inspecting foreign steel cranes to increase safety and reduce labor.