The Development Of CHF-20 Percussive-Rotary Reverse-circulation Drill

This thesis is finished by combining the scientific and technological development plan project in Ji Lin Province: Development of CHF-20 percussive—rotary and reverse—circulation drill. At the present time, the mainly pore-forming method of large diameter compresol pile is adopting rotary drill or percussive drill in china. But the efficiency is very poor of the rotary drill working on original rock. The percussive drill can penetrate stratum easily on original rock or gravel, but it can work on clay stratification and penetrate difficultly on overlying stratum. In the engineering construction, the hole often penetrates different strata, the stratum components are complex, so we must have different drilling methods. At present, most of the drills only have single function, they can only proceed rotary drilling or percussive drilling. The present drilling method is penetrate original rock and gravel with percussive drill and penetrate clay soil and dandy soil strata with rotary drill. The result is as follows: firstly, the drilling efficiency is low, because we must exchange the two drills in the scene and a lot of time is wasted. Secondly, the cost of drilling is too high. There is only the Shanghai mineral exploration plant can produce rotary—percussive drill, but it penetrates stratum mainly on rotary drilling, manual percussive drilling is just assistant, the efficiency is inferior to automatically percussive drill. In abroad, pneumatic DTH with high pressure air compressor and rotary boring drill are often used in large diameter pore-forming, the drilling efficiency and quality are high, but cost much, and are limited by strata. To the above-mentioned problems, on the basis of analyzing existing corresponding products and relevant documents both at home and abroad synthetically, combined normal percussive drilling with rotary drilling method, Percussive—rotary and reverse—circulation drill and outfitting tools were developed. The drill penetrate stratum mainly by percussive drilling and with rotary drilling assistant, satisfied the requirement of using one drill drilling on different strata. Saved auxiliary time and improved drilling efficiency. One drill have two functions, reduced the drill and drilling cost, it is a new kind of drill for road and bridge foundation work construction field, and created great originality innovation in the aspect of combining the drill's rotary and percussive function. As the partial contents of the project plans in the provincial science committee, on the basis of drilling technology, rock soil mechanics, theory of mechanics, optimization theory and the knowledge of computer emulation, this thesis carried out a theory analyses and design calculation for the percussion machinery. The main content is as follows: 1. The research of percussive machinery. The percussive machinery of percussive—rotary and reverse—Circulation drill was developed. The drill can satisfy the requirement of large diameter drilling, especially drilling in hard formation, the efficiency is high. In design, the percussive machinery main and auxiliary hoist clutches have been mounted on the same high speed shaft, the twist moment is low, therefore it is easy to operate clutches, the work is safe and reliable. 2. Various movement parts of the percussive machinery were researched by dynamics simulation firstly by the hypothesized prototypical technology. According to the real structure of various spare parts, material quality attribute and assembly relations, use the Solidworks2005 software to establish hypothesized simulation model, through simulation analysis, we can get the dynamics parameter of centroid displacement, centroid acceleration and average kinetic energy and so on. Made use of the finite element analysis method, proceeded kinematics and dynamics analyses to the percussive machinery, the design parameter and structure became more reasonable. 3. The movement model of the percussive machinery was established. The optimized design was carried on to the percussive machinery. The essential sizes about the percussive machinery were calculated out by compose program of optimized design. The calculation is coincident with the result of design.