The Design And Study On Mechanical Automatic Vertical Drilling System

With the development of drilling technology, vertical drilling system is increasingly used in scientific drilling petroleum drilling and geological drilling. However, borehole deviation is almost inevitable due to complex strata, drilling machines and technologies. Therefore, the design and development of vertical drilling system are tremendously significant.In order to overcome a mass of problems of existing vertical drilling tools, such as high cost, break of drilling tools, airproofing of hydraulic oil, and anti-interfering , hot-resistant abilities as well as slow play under low pressure of inclinometry system, and then to make drilling tools quick play under high pressure, release drilling pressure to adapt to complex strata better, a suit of mechanical automatic vertical drilling system with simple-structure and low cost is provided in this dissertation. Without hydraulic system, electromagnetic teleclinometer and circuit controlled system, my designed system could realize hole- straightening only based on self-adjustment of the lopsided block centroid, which could transform the torque to radial restoring force to achieve incline rectification.The newly designed mechanical automatic vertical drilling system includes upper lopsided block, lower lopsided block, stopper, inner eccentric ring, outer eccentric ring and weaving point of crowned gear teeth. The designed permitted side-play amount of double eccentric rings is 8.7mm, which could realize a slant angle of 0.8 degree.The newly designed mechanical vertical drilling system could realize incline rectification through two methods working together.The limit angle of the upper and the lower lopsided blocks is 90 degrees. When the drilling tools starts to incline, the upper and the lower lopsided blocks would move to a slantwise position at 45 degrees based on their centroid. The upper block drives the inner ring and turns it while the lower block drives the outer ring. The needle bearings are installed in the inner and outer rings to decrease the friction coefficient. The engagement of the rings produce radial restoring force, which is passed by the needle bearing between the inner eccentric ring and crowned gear teeth to the axis of crowned gear teeth. And then, according to the principle of lever, inclined drilling tools are rectified with the weaving point of crowned gear teeth as supporting point.The upper and lower lopsided blocks at the limit angle of 90 degrees would drive the inner and outer eccentric rings rotating respectively to the position at the angle of 45 degrees with inclined bottom surface. If the blocks are in an inappropriate position, the eccentric rings would have a tendency to rotate to the right position. In both cases, mechanical limits of crowned gear teeth axis would be produced to strengthen incline rectification of drilling tools.