Calculation of the actuator system in swash plate axial piston machines by a coupled multibody and TEHL simulation

Abstract

This paper presents a method for coupling a multibody simulation for the actuator system in axial piston machines in combination with a transient, three-dimensional, thermal elastohydrodynamic contact calculation. For the tribological investigation, the oscillating piston/cylinder contact is focused, whereby a simplified model of the actuator system simulates the loads. The developed method allows the integration of a complex tribological contact simulation under mixed friction conditions into a dynamic multibody simulation based on the Newton–Euler method. It is discussed how the accuracy of the results and the calculation time can be improved by the procedure.

Validation of a coupled multibody and TEHL simulation by a piston/cylinder component test rig

“…This includes the specification of the exact operating parameters as well as the consideration of the component-specific material and surface properties. Detailed descriptions of the applied calculation models are presented by Kroneis et al 22 The boundary conditions of the simulation are defined based on the measured operating points (see section 4.1). The axial movement of the control piston is approximated by a sinusoidal function, which indicates a negligible deviation compared to the measurement.…”

“…For this purpose, a separate cooling circuit regulates the hydraulic oil temperature of the axial piston pump. During operation, the temperature in the control chamber and the 2), swash plate replica (3), control piston (4), control chamber/cylinder (5), cylinder housing (6), pressure sensor (7), temperature sensor (8), slipper pad ( 9), swash plate connection (cylinder) (13), swash plate connection (control piston) ( 14), bearing block (15), eddy current sensor ( 16), sheet metal suspension (17), load cell (19), oil drain port (20), shaft (21), force transmission rod (22), oil drain pipe (23).…”

“…The experimental results are subsequently compared with the results of the thermal elastohydrodynamic simulation presented by Kroneis et al. 22 The geometric dimensions and material data presented in Table 1 were used for the test rig setup. For the investigations, the parameter variations of the operating points shown in Table 2 were carried out.…”

“…Based on this design, the cylinder housing can only move in the axial direction. Whereby the force transmission rod (22), which is connected to the load 2), swash plate replica (3), control piston (4), control chamber/cylinder (5), cylinder housing (6), pressure sensor (7), temperature sensor (8), slipper pad (9), position sensor (10), hydraulic test cylinder (11), servo directional control valve (12), swash plate connection (hydraulic cylinder) (13), swash plate connection (control piston) (14), bearing block (15), eddy current sensor (16), sheet metal suspension (17), oil supply port (18), load cell (19), oil drain port (20).…”

“…Based on the results of the two measurements, the validation of a simulation model is presented. The simulation model for the numerical description of the piston/cylinder contact is introduced by Kroneis et al 22 A multibody simulation model based on the Newton-Euler method describes the motion of the actuator system. Identical to the test rig, the simulation is a mathematical representation of the actuator system, which includes the swash plate, the spherical swash plate connection and the control piston.…”