Design And Research Of Screw Drill String Bearing Damper

At present, the number of screw drilling tool grows along with the increasing of oil well. However, there are some problems in the domestic design, processing and maintenance. There are multifarious of failure models in screw drill tool, and the failure of bearing on the drive shaft is the most typical, such as:excessive wear on bearing, crushing, spalling and corrosion etc. The rolling element, the inner and outer ring of the bearing are subjected to a huge impact because of the longitudinal vibration of drill string. And due to the failure of screw drill while increase the cost of drilling. As a result, it is urgent to prolong the screw drill life.The drill string vibration will not only lead to fracture, but also damage the bearing cone bit. And the roller cone drops, the drilling rig will be destructed in further. At present, experts have done a lot of research in the drill string vibration and have achieved good results. But these research focus on the aspects of drill string, and other information on the vibration of the string bearing is very little. In this paper, the stress analysis of the screw drill string bearing is carried out. Designing and installation a damping device to reduce the bearing force. Subsequently, the life of the screw drill string bearing can be prolonged.The dimension of components for the damper are calculated according to the mechanical design manual. A more reasonable design of vibration damper device is designed. At the same time, the disc spring damping element be calculated and checked, and insure the feasibility of working. The screw drill is simplified as three parts:shell.drilling fluid and shafting which is made of rotor, cardan and drive shaft. Establishing the mechanical model of drilling tools under the neutral point of drill string. The virtual prototype model of drilling tool is built in ADAMS software. To analysis the axial bearing capacity on drill string longitudinal vibration at different frequencies, damping element and drilling pressure. From the main perspective of damping effect and working performance stable, we draw the conclusion that C series of disc springs can be used as the most excellent damping component. In addition, the three series of disc springs were harmonic response analysis. And the main analysis points are the displacement and stress in the resonance section. Through compare and analysis the frequency-displacement response curve and frequency-stress response curve, it can get the conclusion that the displacement and stress of C. series of disc springs is smaller compared with the other two series of disc springs. So combined with many different perspectives, the C series of disc springs can be used as the optimal damping component of shock absorber.