PUB - New Design Concepts for the Tribological Contact of Cylinder Block and Valve Plate
A publication on the subject of "Increasing the performance of the piston drum control mirror contact in axial piston machines" was produced as part of the SFPMC in Bath. A new design concept with pressure pockets in the piston drum and a simulative study were published at the conference.
Axial piston machines are the most widely used type of hydraulic displacement machines and are characterized by their high reliability and efficiency. However, in order to ensure the high efficiency, the tribological contacts have to be precisely optimized. One of the three essential contacts in axial piston machines is the contact of valve plate and cylinder block, which is the subject of this paper. In a previous research project, a simulation model was built up specifically for the tribological contact of valve plate and cylinder block. A test rig was developed and installed for the validation of the simulation results. Both, the experimental and the simulation results show that the cylinder block tilts to the high-pressure side. It holds this preferred position nearly constantly for the different load situations over one revolution with four or five pistons pressurized with high pressure at the same time. The tilting increases the danger of solid body contact in the area of minimum gap height. In addition, it leads to temperature hot spots. Both effects necessitate the use of coatings as alternatives to the commonly used leaded alloys. This paper presents new design concepts for the optimization of the tribological contact of valve plate and cylinder block. Additional pressure pockets in the valve plate’s high-pressure kidney generate a torque and thus reduce the tilt angle of the cylinder block. By implementing additional pressure pockets at the cylinder block an imbalance results, which prevents a constant preferred position. Both concepts have the aim to reduce the heat concentration and improving the overall behavior of the tribological contact. The development and comparison of these concepts are based on a numerical analysis.
|New Design Concepts for the Tribological Contact of Cylinder Block and Valve Plate|
Contribution to a book, Contribution to a conference proceedings (2020)