Modelling of the Hydrostatic Relief in the Cylinder Block of an Axial Piston Pump

Axial piston pumps are positive displacement units with the highest possible pressures that can be attained. One of the fundamental pairs affecting the energy efficiency of the hydraulic machine is the cylinder block –valve plate. The work presents the construction of an axial piston pump. Three possible designs of the valve plate were analyzed, namely the design with positive overlap, zero overlap and the one, that is most often used, i.e. with relief grooves. Relationships for the distribution of hydrostatic pressure on the valve plate in the zone high pressure on the inner, outer and middle rings in dependence on the angle of rotation of the cylinder block were developed. Subsequently the location of the resultant hydrostatic forces occurring on the valve plate in the zone high pressure and the upper and lower transition zones relief the cylinder block during its rotation were depicted. Using the MathCad 2001 [5] program, computational simulations of the movement trajectories of the resultant pressing forces acting on the bottoms of the cylinder block located in the zone high pressure and the resultant hydrostatic forces relief the cylinder block during its rotation were performed. For example, the trajectory of the movement of hydrostatic forces pressing and relief the cylinder block for the zero overlap of the valve plate was presented. The work is completed with substantive conclusions.