What is bulldozer?
Bulldozer is a kind of earthwork construction machinery which can excavate, transport and discard rock and soil. It has a wide range of uses in open pit mines. For example, it is used for building dump, leveling automobile dump, gathering dispersed ore and rock, leveling working plate and building site, etc. It is not only used for auxiliary work, but also for main mining work. For example, the stripping and mining of sand deposits, the traction and boosting of scrapers and ploughs, and the reduction of stripping step height with other earthmoving machinery in the non-transportation mining method.
History of Development
Track-type tractor (also known as crawler dozer) was developed by Benjamin Holt, an American, in 1904. It was formed by installing a human-powered bulldozer in front of the tracked tractor. At that time, the power was a steam engine, and then it was successfully developed by natural gas and gasoline engines. The moving crawler bulldozer and bulldozer have also been developed from manual lifting to wire rope lifting. Benjamin Holt was also one of the founders of Caterpillar Inc. in the United States. In 1925, Holt Manufacturing Company merged with C.L. and Best Bulldozer Company to form Caterpillar Bulldozer Company, which became the world's first bulldozer manufacturer. In 1931, Benjamin Holt successfully offline the first batch of 60 bulldozers using diesel engines. With the continuous progress of technology, bulldozers have been powered by diesel engines, bulldozers and looseners are all lifted by hydraulic cylinders. Besides caterpillar bulldozers, there are tyre bulldozers, which are about ten years later than caterpillar bulldozers. Because crawler bulldozers have better adhesion performance and can exert greater traction, the variety and quantity of their products at home and abroad are far more than tyre bulldozers. Internationally, Caterpillar is the largest construction machinery manufacturer in the world. Its caterpillar bulldozers have 9 series D3-D11, the largest D11 RCD, and the power of diesel engine flywheel reaches 634 kw. Komatsu Company of Japan ranks second, and began to introduce and produce D50 caterpillar bulldozers only in 1947. There are 13 series of bulldozers, ranging from D21-D575, the smallest is D21, the diesel engine flywheel power is 29.5 kw, the largest is D575A-3SD, the diesel engine flywheel power is 858 kw, it is also the largest bulldozer in the world; another unique bulldozer manufacturer is Liebhee Group of Germany. R), all of its bulldozers are driven by hydrostatic pressure. After more than ten years of research and development, this technology launched a prototype in 1972, and began mass production of PR721-PR731 and PR741 hydrostatic driving crawler bulldozers in 1974. Due to the limitation of hydraulic components, its maximum power is only 295 Kw, and its model is PR751 for mining purposes.
These three bulldozers represent the highest level of crawler bulldozers in the world today. Several other foreign crawler bulldozers manufacturing enterprises, such as John Deere, Keith, New Netherlands and Dresta, also have high production technology.
The production of bulldozers in China began only after the founding of New China. At first, bulldozers were installed on agricultural tractors. With the development of national economy, the demand for medium-sized and large-sized crawler bulldozers from large mining, water conservancy, power station and transportation departments is increasing. Although the manufacturing industry of medium-sized and large-sized crawler bulldozers has developed greatly, it can not meet the needs of national economic development. For this reason, since 1979, China has successively introduced crawler bulldozer production technology, process specifications, technical standards and material system from Komatsu Company of Japan and Caterpillar Company of the United States. After digestion, absorption and key technology tackling, a pattern dominated by Komatsu technical products in the 1980s and 1990s has been formed.
Since the 1960s, the domestic bulldozer industry has been stable in about four production enterprises, because bulldozer products processing requirements are high, difficult, large-scale production needs greater investment, so ordinary enterprises are afraid to easily step in. However, with the development of the market, starting from the "Eighth Five-Year Plan", some large and medium-sized enterprises in China began to operate bulldozers concurrently according to their own strength, such as Inner Mongolia No. 1 Machinery Factory, Xuzhou Loader Factory, etc., which expanded the bulldozer industry team. At the same time, a small number of enterprises have begun to decline because of poor management and inadaptability to the needs of market development, and some have withdrawn from the industry. At present, the domestic bulldozer production enterprises mainly include: Shantui Construction Machinery Co., Ltd., Hebei Xuanhua Engineering Machinery Co., Ltd., Shanghai Pengpu Machinery Factory Co., Ltd., Tianjin Construction Machinery Factory, Shaanxi New Huanggong Machinery Co., Ltd., Yituo Construction Machinery Co., Ltd. In addition to producing bulldozers, the above-mentioned companies have also begun to engage in the production of other construction machinery products, such as roller, grader, excavator, loader, forklift and so on.
