Analysis of load characteristics in linear bearing with shaft used in space environment for rotary-linear motion

The space devices with a function of rotary-linear motion are usually used in an environment of alternating temperature and high vacuum. Because of the clearances between linear bearings and shaft are large and have coordinated relationship with external loads, while the internal contact situation and lubricating reliability will be considerably influenced by the sequence of load applied with torsion and torque. According to the parameters of environment and load conditions, the mathematical models of internal contact situation and gaps are deduced for the whole shaft and every bearing. Using the damping Newton method, the equilibrium equations of load and deformation are solved, and that the contact stresses and deformations of the whole shaft are gained. From the analysis and calculation, the internal contact situation vary according to the bearing clearances which influenced by the sequence of load applied and the environment temperature. The results show that, the internal load distributions and contact stresses in the bearings are determined significantly by different sequence of load applied on the shaft: When applied the radial load first and then the torque, the maximum stresses inside the bearings will increased about 60 percent than those of the reversed sequence loads. This method could be used for space devices tribological analysis and design in the aerospace engineering field.