Prediction Of The Thermo-elastic And Hydrodynamic Deformation On The Slipper/Swashplate Interface In Axial Piston Pump

The solicitation of Axial Piston Machines(APM)is increasing thanks to its usefulness in several application areas.However,it is still facing problems of the performance loss.Its performance loss is characterised and observed through the low fluid pressure,fractures or elastic deformation of its compounds coming from different aspect of malfunction which are the source of wear,failure or fatigue.To overcome these problems,a proper lubrication design of the slipper/swashplate interface(which is one of the most affected part of APM to be lubricated)is essential for separating the solid bodies from each other and having the minimum possible of thermoelastic and hydrodynamic deformation which is one of the major sources of the performance loss;but the complexity of the physics phenomena involved in addition to the slipper motions under swashplate make this a difficult problem.To better understand the slipper/swashplate interface lubrication and its deformation mechanism,a numerical model has been developed for predicting the thermo-elastic and hydrodynamic deformation of the design.The behaviour and motion of slipper and swashplate have firstly been analysed.Partitioned solvers considering the fluid pressure and temperature distributions,solving respectively Reynolds equation and energy equation are modelled.The solid body dynamics from transient loads and thermal effect have been well developed.The specific materials for slipper and swashplate have been used for simulating the elastic deformation to analyse the evolution of wear and possible fracture of the slipper.To validate the developed numerical simulation,a typical slipper test-rig was designed and manufactured.Several sensors were embedded in the specific slipper pad for measurement during the experimental part: three(03)displacement sensors,three(03)temperature sensors,and a pressure sensor in the slipper pocket.The three(03)displacement sensors measure the distance between the swashplate and the slipper representing the oil film thickness which is the most influential parameter of the lubrication mechanism.So,these displacement sensors can measure the direct distance between the oil film thickness for different of shaft rotation speed and different value of supply load in order to understand the behaviour of the fluid.The developed numerical calculation was used to conduct case studies demonstrating the slipper load carrying capacity and the effect of the thermal,elastic and hydrodynamic deformation of the slipper/swashplate interface.A multi-modelling approach based upon a design of experiment study and the full numerical model explored the interdependence of variables in a multi-land slipper design.A specific test rig is designed for the test and measurement of oil behaviour on slipper/swashplate interface of Axial Piston Pump(APP)to validate the theoretical and simulation results.