In recent years, with the development of construction machinery industry, foreign truck crane technology has been greatly improved, the quality of the whole machine is more and more small, the lifting performance, under the condition of same weight of about more than a decade ago was reduced by 20% or so, due to the decrease of the light weight, make the vehicle with as few shaft number (especially a large tonnage crane), in this way,Greatly simplifies the structure of the vehicle, reduces the cost, and improves the operation capacity and use economy of the crane.Therefore, now the sales price of imported truck-crane with the same tonnage has dropped significantly compared with the previous ten years, which has caused a great impact on China’s domestic market.
Internal and overseas crane on the entire quality control, there is a big gap in xuzhou heavy machinery co., LTD., the third generation of products (basic level) on behalf of the domestic automobile crane technology as an example, the first generation of eighty s used to finalize the design product, the second to finalize the design product in the ninety s, the third to finalize the design product after 2000,The quality control of the whole machine is shown in Table 1 (excluding the weight of counterweight for the whole ground series and truck cranes above 80 tons) and Figure 1 and Figure 2. It can be seen that although the dead weight of the whole machine with the same tonnage decreases gradually, the change is not large, indicating that the technical progress is slow.The chart also lists the deadweight of the latest product of Liebherr’s LTM series, which shows the obvious gap between domestic products and Liebherr’s LTM series.
The main factors restricting the quality of the whole truck crane are:
First, the technical level of accessories, taking the engine as an example, ten years ago, the domestic crane used 6135Q diesel engine, rated power 160KW, dead weight of 1200KG, and now the use of the basic same power D6114 engine, dead weight only 700KG, a drop of 40%.In recent years, the rapid progress of domestic engine technology, a great contribution to the reduction of the quality of the whole crane, and the technical level of the gearbox, drive axle basic no progress, still restrict the development of the quality and technical level of the whole crane, for the car, wire rope, cylinder, winch and so on in the weight control of technical progress is very little.
Second, the lack of new materials and new technology.At present, the performance grade of foreign wheel crane is 960 kg steel, while the performance grade of domestic material is 460 kg.In addition, for non-metallic materials, foreign on material performance and mature production technology, used in crane scale increasing, and domestic for shortage of material or technology is not mature in the crane used rarely, glass fiber reinforced plastic materials in recent years has been applied on the crane, but the process still lack, need to further efforts.
The 3rd, design means is quite backward or master to new-style design tool still not enough skilled, make present product development is basically in imitate design stage, and developed country already entered complete optimize design stage on product development, its also accumulated rich experience on the control of complete machine quality.
Fourth, lack of perfect test, research system, technical innovation ability is insufficient.At present, the domestic crane production enterprises generally have weak foundation, weak economic strength, insufficient investment in product test research or the heart is willing but the strength is insufficient, not fully equipped with the conditions of independent test and research.Generally, innovative technologies are directly tested on products, so the risk of technological innovation is great, which affects the innovation consciousness of technical personnel to a certain extent.
In order to develop the overall quality control of domestic truck crane and shorten the gap with developed countries, efforts must be made from the following aspects:
1. The layout of the whole machine should be simple, smooth and highlight the key points to promote the application of micro-electronic technology;
Second, the specific structural details of the design to be further refined, designers from the consciousness to abandon the problem on the design idea, the design of each part to achieve the optimization of the structure;
3. For the structural parts that have a great influence on the quality of the whole machine, a set of scientific and reasonable design methods is summarized by using advanced design methods and combining analysis and tests to carry out comprehensive optimization design.
4. To purchase parts, cooperate with supporting manufacturers to find out their gaps, help them improve, make progress together and develop together;
5. Increase the research and application of non-metallic materials and their production processes