Analysis of loading distribution for SRB and TSRB combined bearing

Combined bearing, which consists of spherical roller bearing and thrust spherical roller bearing, is an important support in various low-speed and heavy load institutions and the stability of its running state is a strong guarantee for the normal operation of the supporting mechanism. Basing on the wellbore trajectory control tool, the loading distribution of combined bearing under pure radial and axial forces is studied theoretically. Two kinds of limit state of rolling elements movement named "Odd press" state and "Even press" state is considered and the Hertzian line elastic contact model is used to deal with the contact between roller and raceway. The calculation results of contact stress and radial displacement are very close to the analysis results, and the accuracy of the analysis results is verified by the radial displacement experiment. The results show that the radial load will lead to the radial displacement of the combined bearing axis, which is about 5.81×10-3 mm. The radial displacement can affect the guiding accuracy of the tool to a certain extent. The radial displacement can be reduced by adjusting the bearing structure design parameters .This research can be used to design SRB and TSRB combined Bearing in actual engineering problem.