New generation of the satellite hydraulic pumps

Abstract

Hydraulic satellite machines are known and produced in many versions, recognizable by the number of humps on their inner rotor and external gear, and therefore by the number of cooperating gears (satellites). All known shapes were however designed on the base of preliminary assumption that rotor’s and external gear’s pitch lines are formed by merging arcs, tangent  to each other in the. This assumption makes calculations easier, but the curvature radius of the pitch lines changes instantly in their merging points. Tests made in the Department of Hydraulics and Pneumatics of the Gdansk University of Technology proved that satellite motors may work also as a pump. All known shapes were however designed for motor work - mainly for low-speed, high-torque motors. Sudden changes of the pitch line’s curvature strongly affect velocity and acceleration of pump’s moving parts and forces between them. Because of that, in the pump mode fast wear of teeth in the points of small curvature radius is visible. The obvious effect is reduced durability and high noise emission. To eliminate all those problems the new mechanism, designed for the pump is necessary.