Computer Aided Design of Axial Piston Machines Having a Roller Piston Bearing

Abstract

Swashplate axial piston machines are simple, compact and low price. This simplicity is at the expense of piston transverse forces which limits machine characteristics. The aim of this study is to propose more effective developed design using roller piston bearing. Ball bearing was proposed to reduce transverse forces acting on the piston end of the axial piston machines. The proposed roller bearing design will provide line contact bearing between roller and cam contour compared to point contact of ball bearing arrangement. The roller runs on a flat surface contour formed on the swashplate which is simpler in manufacturing process. The sliding friction between swashplate and slipper is replaced by a rolling friction between roller and runway of cam surface contour. Results show the feasibility of the developed design. The proposed design promises to increase the pressure limitation of the ball bearing arrangement. Parameters such as piston displacement, cam action angle are the same for both roller and ball piston bearing. A comparison analysis was also performed between two alternative cam contours, sinusoidal and linear piston displacement. The selection criterion was based on piston transverse torque. Results show that sinusoidal piston displacement is much better choice than the linear one.