Abstract:
A new type of thrust foil bearing is proposed. The advantage of this bearing is that it can change the dynamic characteristics such as the axial stiffness of the foil bearing by the combination of bump foil and flat foil. Taking the new type of thrust foil bearing as a research object, the deformation of top foil and bump foil of the thrust foil bearing is analyzed by elastic mechanics theory, and the non-isothermal Reynolds equation is obtained by combining viscosity-temperature equation, three-dimensional energy equation of the gas film and isothermal Reynolds equation. The non-isothermal Reynolds equation is processed by the small perturbation method to obtain the steady control equation and differential control equation of the gas film pressure. Using finite difference method and point-by-point relaxation iteration method to solve it numerically, the air film pressure distribution, air film thickness distribution, foil deformation distribution, air film temperature distribution, axial stiffness, and axial damping of the thrust foil bearing are obtained. The results show that the dynamic stiffness and damping of foil bearing decrease with the increase of wave arch half-length, wedge gap height difference and wave arch radius. Dynamic stiffness and dynamic damping increase with the increase of whirl frequency ratio, rotational speed, wave foil thickness, top foil thickness and bearing outer diameter.