Designing a Control and Containment Device for Cradle-Mounted, Axial-Actuated Swash Plates

Many axial-piston pumps utilize a swash plate for regulating discharge flow. In this research, the required control and containment forces are examined for a cradle-mounted, axial-actuated swash plate. These forces are described in closed-form for providing the designer with information that is necessary for sizing these critical components within the pump. In this research, it is shown that a proper design of the control device may be used to load the cradle bearings equally during high-pressure operation. While previous research has shown that a transverse-actuated swash plate will tend to dislocate itself from the cradle during high speed and low pressure operation, this research shows that an axial-actuated swash-plate tends to keep the swash-plate well seated within the cradle during all operating conditions. The information presented here is generalized for typical characteristics of swash plates that are used within the industry and is therefore useful for analyzing existing designs as well as new ones.