Development history and latest technology of gantr

The development history and latest technology of shipbuilding gantry crane (2)

II. The latest technology

since our company began to design large shipbuilding gantry crane with relevant data in the mid-1990s, it has experienced three stages: imitation, improvement and independent research and development. From the technical development of shipbuilding gantry crane, it mainly embodies three aspects

(1) overall structure

in the early stage of our design, double beam structure is generally used, such as the 300t of Nantong COSCO Kawasaki × 116m gantry crane and Bohai Shipyard 480t × 122m gantry crane. With the increase of the crane span, the problem of the lateral stiffness of the main beam of the double beam gantry crane becomes more and more prominent, causing the upper trolley to deviate. Therefore, the large-span shipbuilding gantry crane generally adopts the single beam structure

since 2004, we have improved the frame structure of the upper trolley of the double beam gantry crane for shipbuilding, adopted the rigid and flexible leg form similar to the gantry structure, and solved the problem of the upper trolley deviation with a rigid and flexible frame structure, and obtained a patent

at present, the overall structure of large shipbuilding gantry crane basically adopts two forms: double beam and single beam. The span of double beam has reached 208 meters, and the span of single beam has reached 239 meters. These two forms have their own advantages and disadvantages: the double beam is easy to maintain, the three hook height is the same, the main beam structure is simple, easy to manufacture, but the self weight is relatively heavy; The self weight of the single beam is light, but it is difficult to get off the trolley for maintenance. Two types of shipbuilding gantry cranes are generally designed according to the requirements of users

(2) mechanism form

the mechanism form of large shipbuilding gantry crane has been greatly improved. Due to this form of gantry crane, the lifting height is generally about 80-90 meters, and the lifting weight of a single hook is 300t-500t. How to reasonably configure the form of lifting winch and reduce the weight of the trolley is one of the main goals pursued by the design. Due to the large lifting capacity and high lifting height, the lifting winch of the gantry crane designed in the early stage generally adopts the form of double drums. The drum is arranged on both sides of the upper trolley, and the steel wire rope is directly lowered from the drum to the hook pulley block. Since the component weight and load weight are at the cantilever end of the upper trolley, the dead weight of the upper trolley is heavy

at present, in terms of the layout of the lifting mechanism of the trolley, we generally use the single drum lifting winch and the chain driven winch rope arrangement mechanism. The winch is arranged in the middle of the trolley, which not only reduces the self weight of the winch, but also uses the weight of the winch to balance the weight of some lifting loads, thus reducing the self weight of the trolley. With the improvement of the overall manufacturing level of China's machinery industry, the hard tooth reducer has replaced the medium hard tooth reducer, and the steel wire rope with new structure has replaced the traditional steel wire strength, which also further reduces the weight of the mechanism. The weight of the new car can be reduced by about 1/3 compared with that of the traditional car

(3) electrical control

the electrical control system of large shipbuilding gantry crane generally has high requirements for speed control and safety protection of each mechanism. At first, DC speed regulation system was generally used. With the improvement of frequency conversion control technology, AC frequency conversion control system is mostly used at present, which reduces the investment cost, improves the reliability of control, and facilitates the daily maintenance. The spokesman of the general office of the Standing Committee of the National People's Congress said in his speech that it would be repaired and maintained in 2015

large shipbuilding gantry cranes generally have high requirements for the lifting and walking of the upper and lower trolleys, the walking mechanism of the rigid leg side and the flexible leg side of the crane, and the synchronization of the two cranes when they are hoisted together. At present, in the synchronization of the lifting structure, absolute value encoder is used for detection and control. On the traveling mechanism (including the rigid and flexible legs of the upper and lower trolley and the crane), absolute value encoder installed on the detection wheel is used for the detection and control of the traveling distance. For the crane traveling mechanism, the ground induction switch is added to correct the possible errors of the encoder. 2. Only when it is used correctly can the detection advantage error of the pressure shear experimental machine be brought into play, At the same time, an out of tolerance limit switch is installed at the flexible hinge to prevent extreme conditions. The installed capacity of large shipbuilding gantry crane is large, mostly about 2-4 kW, so the requirement of energy saving is also one of the factors that need to be considered in the design. At present, the energy-saving design generally adopts AFE (igpt) common DC bus, and the transmission system with energy regeneration feedback, which can save a lot of energy (about 20~50% can be saved) in actual operation

the safety protection of large shipbuilding gantry crane is more prominent than that of general cranes. In addition to the conventional safety protection functions, we also installed industrial video system, laser anti-collision system, crane management system, etc. on this crane

in order to know the use of the equipment in time and analyze the cause of the failure and guide the maintenance work in time when the equipment breaks down, we have also added a remote monitoring system on some cranes to use the Internet to know the use of the equipment in time and guide the treatment of the failure