Abstract: As one of the key friction pairs of the axial piston pump, the temperature distribution of the valve plate is related to the performance and working life of the axial piston pump. In order to obtain the effect of load pressure on the temperature of the oil film of the valve plate, an in situ measurement scheme of the temperature of the valve plate is proposed. The root-mean-square errors of 5 common interpolation methods are compared. The biharmonic spline interpolation based on Green’s function has the smallest interpolation error. The oil film temperature under 7 pressures is measured, and the collected discrete temperature is retrieved through the corresponding interpolation algorithm to obtain the oil film temperature field of the valve plate. The results show that The highest temperature appears in the exit part of the high pressure side at the bottom dead center, and the lowest temperature appears in the reinforcement bar of the low pressure side. The average temperature rise in the escape part of the high pressure side at the bottom dead center is the largest, and decreases first with the increase of the load pressure, reaches the minimum at 15 MPa, and then rises.,and the average temperature rise at the reinforcement bar of the low pressure side is the smallest. With the increase of load pressure, the maximum temperature rise of the measuring point of the distribution pair decreases first and then increases. The mean temperature rise and the minimum temperature rise are less affected by the pressure. In situ testing scheme can obtain more accurate oil film temperature of the valve pair, and further research can be carried out from the Angle of optimizing the triangular groove structure of the valve plate.

Key words: axial piston pump, valve plate, temperature distribution, biharmonic spline interpolation, stress