Study Of The Unsteady Temperature Field Of Tire

In this paper the unsteady temperature field of tire at the phase, which is from starting to braking is studied when hysteresis heat and friction heat are considered. At the base of summarizing the basic knowledge of tire, the investigative production of tire at overseas and internal field, and the aim and significance of the task are analyzed. The investigative content are given. In this paper by the analysis of theory of hysteresis heat of tire, the relation of stress and strain is summarized, and the heat generation rates of ten types of rubber are studied with experiment. The dependence of heat generation rate of every rubber on temperature and frequency is investigated, and quantitative equations used at the study of temperature field of tire are given. The thermal properties of ten types of rubber of tire are measured in this paper by using the laser light instrument of LFA447. The higher veracity and accuracy are validated by experiments. Therefore, the reliability of the experimental result is higher. The linear relations of thermal diffusivity, thermal conductivity and specific heat of rubber on temperature are obtained by the regression analysis, which are used to forecast the thermal properties of rubber. And the average values of these thermal properties are obtained at the temperature range, which provide the basic data for the numerical simulation of unsteady temperature field of tire. When the tire is running on the road surface, it exchanges heat with environment by the form of convective heat transfer. In this paper the rotating disk immersing a gaseous free stream flow is experimentally investigated with the naphthalene sublimation technique and dimensionless equation is obtained at the range of radius of disk. The rule of convective heat transfer of disk is transformed to a specific tire by using similarity principle, and the dependence of convective heat transfer coefficient of the specific tire on velocity is confirmed. From the relation it is founded that the convective heat transfer coefficient of tire linear increases with an increase of velocity, which provides a quantitative equation for the study of temperature field of tire. The study of friction heat of tire, which depends on the study of friction properties of rubber, is innovation in this paper. The friction experiment is carried out on the high-speed experimental apparatus by using the principle of friction of rubber block on road. The friction coefficients of tread rubber are measured, the gauss equations of frictions only considering press are obtained at different velocities. By analyzing the influence of velocity and press on friction a calculation equation is given. The equation can be used to forecast the friction of tread rubber and analyze the temperature of tire surface. The friction coefficients of different compound of tread rubber are discussed in this paper. It is found that the friction force and friction coefficient are appropriately increased and the resistance of friction of BR9000 is worse than that of SBR1502 and SBR1712. With rational supposition the planar thermal model of unsteady temperature field of tire is founded, the finite element format is provided and the initial condition and boundary condition are given. The simulation program of unsteady temperature field of tire is programmed. The unsteady temperature fields of tire only considering hysteresis heat, and hysteresis heat and friction heat at the same time are simulated and analyzed. It is found that the friction heat of the starting phase of tire is not neglected by analyzing the investigative result. In order to validate the reliability of the simulation result, The surface temperature field and internal temperature field of 165/70R10 tire are experimental studied on the apparatus. It is found that the experimental result is close to the simulant result. On the basis of the study of temperature field of tire, the dynamic properties of eleven types of tread rubber are studied, and the results will provide basis for the compound design. The following works need to continue aftertime. The friction properties of tread rubber will be studied at different conditions. The convective heat transfer will be studied by broadening the range of velocity. The study of heat properties of rubber of tire will be continued. The temperature field of tire covering starting, steady running and braking is studied by founding reasonable model.