Development of a Matlab application to predict the sliding wear of swashplate-pins region on axial piston hydraulic motors

Perfezionamento e collaudo del motore idraulico TH68.This master’s degree thesis is performed in collaboration with Bonfiglioli group, in a more specific way, with the Hydraulic Motors department. The target of the work is to obtain a method to estimate the wear of a hydraulic motor thus compute its lifetime. The motor considered is a new generation axial piston swashplate motor, it is designed with a feedback control system for varying the displacement according to the input signal that the operator applies, trough the joystick, for the specific operation that is going to perform. This kind of device is used in the track drives dedicated to construction machinery which can provides an output torque of up to 17,000 Nm, designed for a continuous pressure of 450 bar, a maximum oil flow of 160 l/min and it can go beyond the 2: 1 displacement ratio that is normally seen as a limiting factor. During the pre-production tests performed both by Bonfiglioli and main costumer some problems have arisen, but my research is focused on one of them: the wear between the swash plate and the pins on which it oscillates. The analysis is performed on given database obtained during both the test at the bench and on the field, in which a reduction of maximum displacement vs. time has been seen. To study this behavior Matlab software is used. Taking as input motor design data and tests data, I calculated the correlation between displacement and time, computing the wear of plate pin region for each test. Knowing this, is possible to perform a regression problem based on data fitting in which, using a formula with the principal factors of wear, it is possible to compute the weight coefficients of each component. This will allow to obtain the resulting wear for both field and bench tests. Once the coefficients have been found, it is possible to perform prediction of different layout of the motor varying the input data according to the modification performed. To do this, an application was created. This software allows the operator to change the main motor parameter and to compute the real lifetime of the optimized motor.