Modeling and Analysis of the tilt behavior of the cylinder block in a high-speed axial piston pump

Increasing the rotating speed of the axial piston pump is effective in improving the power-to-weight ratio. However, the cylinder block tilts severely at high speed, which causes significant leakage. In this paper, a dynamic model of the rotating assembly in a high-speed axial piston pump is established to investigate the tilt behavior of the cylinder block when fully considering the relevant factors within the whole rotating assembly, such as the tilt moments due to the inertia of piston-slipper assemblies and the periodic pressure in piston chambers, the elastic deformation of the shaft, and the nonlinear bearing characteristics of the oil film. Furthermore, the cylinder block tilt behavior is measured to validate the established dynamic model. The theoretical and experimental results show that the tilt angle of the cylinder block increases with the increasing rotating speed. And at high rotating speed, the cylinder block tilts much more severely under low outlet pressure. Finally, the bearing capacities of the oil film and the spline coupling are analyzed to find out the dominant factors affecting the tilt behavior of the cylinder block.