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The transformation and upgrading of China's tower crane industry is just in time

  來源:www.whosonmyspace.com

From 2010 to 2014, China's tower crane manufacturing industry grew fastest in three years. In the three years, tower crane manufacturing enterprises surged from more than 280 to nearly 600. This is mainly due to the investment effect of 4.8 trillion yuan. By 2013, with the decline of the investment effect of 4.8 trillion yuan, the growth of the whole industry of tower crane manufacturing declined seriously. It is an indisputable fact that China's economic growth will continue to slow down in the next five years. This is a rare opportunity for the country to adjust its industrial structure and change its development mode.
Similarly, tower machinery manufacturing industry is also facing adjustment. The adjustment of tower crane manufacturing industry will present three trends:
First, the industry will speed up shuffling, eliminating the bad and preserving the good.
Second, the modernization level of production and manufacturing in the industry will be improved, so as to improve production efficiency and product quality.
Third, the concentration of the industry will continue to improve, that is, some large-scale production and manufacturing enterprises will emerge.
Industry will speed up shuffling
From 2010 to 2014, the number of tower manufacturing enterprises increased from more than 280 to nearly 600. This is the effect of economic stimulus, on the other hand, the threshold of tower manufacturing is low. With the slowdown of national economic growth, market demand will shrink significantly from 2012 to 2013. At the same time, the user's awareness of tower crane product quality is constantly improving, and some small-scale enterprises with poor product quality and performance will be eliminated. On the other hand, Xugong Group, Sany Heavy Industry, China Construction Machinery and other large enterprises have also entered the tower machinery manufacturing industry, which is also an important factor in accelerating the shuffling of the tower machinery manufacturing industry.
The modernization level of production and manufacturing in the industry will continue to improve
Tower crane is a kind of non-compact equipment. Structural parts account for a large proportion of products, but the processing accuracy requirements of these structural parts are comparable to those of machine parts. Therefore, the rationality of manufacturing process and the modernization level of production technology and equipment have a great impact on production efficiency, product quality and production cost. The rationality of manufacturing process refers to the rationality of the whole process from raw material processing, welding, machining to painting, which has a direct impact on production efficiency. Second, the modernization of process equipment, which has a direct impact on product quality. At the same time, the improvement of the modernization level of process equipment can minimize the dependence on labor, thereby reducing the labor cost. However, the modernization of manufacturing technology in tower crane manufacturing enterprises is not only to add a few welding manipulators, but to systematically modernize the whole process. First of all, we need to have a correct understanding of the concept. At present, there are only a few construction elevator manufacturing enterprises in China, basically realizing the modern production and manufacturing of process flow and process equipment. This is also the direction that the tower manufacturing industry needs to work hard, and the future development trend.
Industry concentration will continue to improve
In 2010, relevant agencies made a statistics on the concentration degree of tower crane manufacturing industry. The concentration degree of tower crane manufacturing industry is 28%, which is much lower than that of automobile crane 99.5%, caterpillar crane 99%, loader 99%, and other construction machinery such as concrete pump. The level of industry concentration reflects the degree of standardization of an industry and the "cost-effective transparency" of products. In recent years, although the concentration of tower crane manufacturing industry has increased, such as Zhonglian Heavy Branch's output value as high as 8 billion yuan, monopolizing more than 30% of the industry's market share. But the development of the whole industry is still very unbalanced, especially the industry concentration and product cost-effective transparency level is still relatively low. Mainly reflected in the product configuration, performance, quality and other disparities, but the price gap is not large.
In the next five years or so, through accelerating shuffling, eliminating the inferior and preserving the superior, and improving the level of production and manufacturing modernization, the industry concentration will continue to improve.
Development Trend of Tower Crane Products in the Future
It has been nearly 30 years since the introduction of foreign tower crane technology in the 1980s to produce tower cranes. Over the past 30 years, China has made great progress in tower crane manufacturing, but the technological level of tower crane has not improved much. With the development of science and the progress of the times, tower crane products will continue to improve.
There are three trends in the future changes of tower crane products: first, the flattening trend of medium-sized tower crane (63t.m~500t.m) and the booming trend of large-scale tower crane (over 600t.m); second, the technical performance of the three main mechanisms of tower crane will be continuously improved, especially the performance of hoisting mechanism; third, the application of digital technology in tower crane control system will continue to be popularized.


  Trend of Flattening and Arming of Large Tower Cranes
(1) Advantages of flattening of medium-sized tower cranes. The advantages of medium-sized tower crane flattening are embodied in two aspects: manufacture and use.
A. Production and manufacturing advantages. Flat-head tower machine manufacturing can achieve more modular production, can promote enterprises to improve the modernization of process equipment and means of production, and the modernization of process equipment and means of production, can improve production efficiency, improve manufacturing accuracy and reduce production costs.
B. Use advantages. The first is the modular structure of flat-head tower crane, which can minimize the tonnage of lifting equipment when installed and dismantled. Compared with hammer-head tower crane, the installation and dismantling of flat-head tower crane is more safe. Second, in the future, the scale and volume of the project will be larger and larger, and the density of group tower operation will be larger and larger. The interference of flat-head tower crane operation is better than that of hammer-head tower crane.
In addition to the above advantages, the force direction of the upper and lower chords of the crane arm is the same when the working radius of the flat-headed tower crane is different, while that of the hammer-headed tower crane is a statically indeterminate structure. The force of the upper and lower chords of the crane arm is changed when the working radius of the tower crane is different due to the action of the pull rod. This is also a major advantage of flat-head tower crane. It should be said that the flattening of medium-sized tower cranes is an inevitable trend of technological progress and the progress of the times.
(2) Large tower cranes adopt the advantage of booming.
A. When a movable arm tower crane works, the lifting arm does not produce additional moment (except rated moment of tower crane, the downward impact force caused by the self-weight of the lifting arm will generate an additional moment for the tower crane, especially for the large horizontal arm tower crane, which is generally much larger than the rated lifting moment of the tower crane. This is very harmful to the tower body of the tower crane. In the luffing operation of the boom tower crane, the angle of the boom is changed, and the boom is mainly under pressure in theory. Therefore, the section of the boom and the tower body can be relatively small.
B. The balance arm is short. Because the amplitude of the boom tower crane changes the angle of the boom, the boom does not generate additional torque, so the balance arm of the tower crane can be relatively short. For the group tower operation of super high buildings, the advantage of boom tower crane is irreplaceable for water balance boom tower crane.
C. Lifting performance of boom tower crane. The lifting of the variable amplitude of the boom tower crane makes the installation height of the tower crane relatively low, and at the same time, it can minimize the encroachment on the extraterritorial space of the construction site.
Of course, the boom tower crane also has the disadvantage of large energy consumption.
The technical performance of the three main mechanisms of tower crane will be improved continuously.
The performance of the three main mechanisms (hoisting, rotating and amplitude changing) of the tower crane, especially the hoisting mechanism, is very important to the overall performance of the tower crane. But at present, there is a big gap between the technical level and performance of tower crane hoisting mechanism in our country, such as LVF frequency conversion hoisting mechanism using German "Flander" direct cylindrical gear reducer, and the one-type mechanism of Botan MC320 tower crane. But it seems that the proportion of hoists with backward technology is larger. For example, the RCS lifting mechanism of Botan F0 series and the PI-type lifting mechanism of Liebherr's early stage. Both of them are the technologies of the last 60 years. The former has the disadvantage of high energy consumption. Especially when the four and five gears speed regulation are switched each other, great braking moment and mechanical impact will occur between the two motors. At the same time, when the four and five gears are switched, the current impact will be great, while the latter has the disadvantage that the input and output axes of the reducer are parallel. Obviously, the motor and the steel rope drum interfere with each other, and the diameter of the drum is limited, resulting in the uneven arrangement of the hoisting wire rope, and the early wear and service life of the wire rope is short. At the same time, the transmission efficiency of the reducer used in the PI-type hoisting mechanism is low. Although some adopt medium-hard gear, the relative energy consumption of the type is still large.


  In terms of technology and usage, the hoisting mechanism of medium and large tower cranes (150t.m~500t.m) should adopt straight cylindrical gear reducer, L-type arrangement and variable frequency speed regulation. This will become the trend of change in the future. At present, several domestic reducer factories, such as Guomao, Boneng and Jiepai, can basically meet the needs of the configuration of lifting mechanism of medium-sized tower cranes in technology. If they can be applied more, they will objectively promote the improvement of technical level and quality of these enterprises'products.
The application of digital technology in tower crane control system will continue to popularize
At present, digital technology has been widely used in various fields and industries, but the application of tower crane products has not been more fully reflected, especially in the location device of each part of the tower crane, almost all of them are mechanical. In recent two years, some manufacturers have made some electronic products, but these products have many functions, besides satisfying the basic control and anti-collision of tower crane, they also have GPS positioning and powerful data management functions. More importantly, the price of products is too high, so they can not be popularized.
Digital technology is applied to tower crane control system, mainly to realize digital monitoring of moment limit, lifting limit, lifting limit, rotary limit, variable limit, etc. Its principle is to collect information by sensors and proximity switches, process data by amplifiers and analog-to-digital conversion (A/D conversion), and control the executing mechanism by switching input-to-output conversion (I/O conversion). If according to the above control principle, the cost of a digital control system for a medium-sized tower crane should be less than 5000 yuan, which is easy to be accepted by users and popularized. However, the performance of tower cranes will be substantially improved.
The application of digital technology in tower crane control system has the following advantages: First, the accuracy of each limit control of tower crane is greatly improved. Second, operators can monitor tower crane operation in real time. Third, it has the function of "fault tolerance" and "interlocking", such as tower crane can avoid misoperation when lifting. 4. It has anti-collision function for group tower operation. In a word, the application of digital technology in tower crane control system can improve the intelligence level of tower crane qualitatively and the safety of tower crane greatly.
Tower crane is a kind of non-compact equipment, and its own technology is not very high. Future technical improvements and breakthroughs should be made. First, the frequency conversion hoisting mechanism with motor power above 55 KW should realize the secondary inversion of current, that is, the hoisting mechanism should be reduced, and the motor should feed back current to the power grid when it is in the power generation condition, so as to save energy. But this is largely due to the change of concepts in manufacturing and use. Thirdly, the improvement of tower crane intellectualization level, and the improvement of intellectualization level, it is necessary to increase the application of digital technology. Thirdly, the improvement of tower crane intellectualization level, and the improvement of intellectualization level, it is necessary to increase the application of digital technology.
The next 20 years will still be the golden development period of tower machinery manufacturing industry. However, market competition and industry competition will become more intense. Enterprises with certain scale and strength should improve their innovative thinking and ability, especially the modernization level of production and manufacturing, enhance their competitiveness in the industry and lead the development of the industry.

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