Investigation of the effect of the gap on the friction forces in the piston pair of the axial piston hydraulic machine

Abstract

In modern positive displacement hydraulic drives, axial-piston hydraulic swash plate machines are widely applied, which is due to their high-energy consumption and simplicity of design. However, a large dead-band significantly reduces their control range. The friction force in the piston mechanism and the volume losses significantly affect the dead-band. One of the factors that influence the value of the friction forces in the ‘piston-cylinder’ pair is the value of the relative gap in this kinematic pair. This article presents an analysis of the results of experimental researches on the effect of the gap size on the friction forces in a piston pair. The analysis allows us to develop recommendations for choosing the size of the gap between the piston and the guide bushing, respective to the minimum values of the friction forces, which as a result will lead to a decrease in the dead-band of the hydraulic machine.