Design Of Associated Device Of Tribometer And Research On High On High Temperature Tribological Preperties Of Lubricant

Friction testing machine is the most basic element of tribology research and development. “To do a good job, one must first sharpen one's tools”, with the deepening and development of tribology research, the requirements on the function, precision and reliability of the tribological testing device are also higher and higher. In order to meet the requirements of research on tribological properties of lubricating oil at high temperature, based on the National Natural Science Foundation and the National 973 Project, combine with the development frontier of testing theory and technology, this paper develops a kind of high-precision temperature control system for the high temperature four-ball friction testing machine, and designs a sort of grinding spot measuring device and related softwares for the standard four-ball friction testing machine. Meanwhile, this work combine with PDSC and Raman spectrometer tests, the tribological properties of TMPTO at high temperature are studied by experiments, and the influence of different additives on the critical transition temperature of friction coefficient of lubricating oil is studied to research the physical significance of the critical transition temperature of friction coefficient. The main results and conclusions of this paper are as follows:(1) A new type of high-precision temperature control system is developed for high temperature and low speed four-ball friction testing machine. Based on the finite element analysis and theoretical calculation results, design the relevant structure of the test vessel, add the constant temperature circulating water device, combine with subsection PID parameter adjustment, so as to achieve high-precision temperature control of heating and constant temperature section under different temperature conditions. Test results show that, the temperature control system can realize heating at different rates and keep low temperature fluctuations, and the fluctuations range of the temperature decrease from ±4? to ±0.5?, and realize the purpose of high-precision temperature control.(2) By setting the repeatability test in the test environment and combining with the effect of viscosity change on lubrication state, verify the reliability of high temperature and low speed four-ball friction testing machine to test the relationship between the friction coefficient of lubricating oil with the oil temperature. Test results show that, the system data obtained from the three tests can be repeated well. The viscosity change has little effect on the lubrication state. The whole system can keep good reliability.(3) The tribological properties of TMPTO and additives are studied by four-ball friction testing machine at high temperature and low speed. Test results show that, under the conditions of adding different anti-oxygen additives, the critical transition temperature of the friction coefficient in the four-ball test shows the same temperature variation with the initial oxidation temperature of PDSC. To a certain extent, the change trend of the average friction coefficient and the peak intensity of the =C-H and C=C stretching vibration peaks in the Raman spectra show the same corresponding relationship. The oxidation of oil obtained by the four-ball test is not obvious, which is determined by the infrared spectrum analysis. This phenomenon may be related to the test environment.(4) In view of the particularity of the grinding spot measurement of the standard four-ball friction testing machine, combine with the characteristics of digital microscope, use the structure of supporting beam embedded with adjusting nut, combine the magnetic field force and mechanical positioning technology, and research, design and manufacture a set of digital grinding spot measuring device with fast positioning function, and make the grinding spot observation technology realize the purpose of the computer screen display, measurement and recording. This device has already declared the national invention patent and obtained the authorization(patent number: 201410200402.6).