| Trend of the rapidly development of the transportation industry and the auto industry has pushed the tire industry made leaps and bounds. China’s tire production has ranked in the forefront of the world, but the high quality and representative brand tires are scarce. The European and American countries continuously revised testing standards improve tire quality requirements. Both manufacturers and distributors focus their eyes on tire quality inspection of automobile with higher requirements. In the strictly controlled quality management system, the tire dynamic balance performance is paid more attention. Because when the vehicle at high speed, the tire unbalance will cause the wheel bumps and swing, operating performance, stable performance, safety performance and comfortable performance are impacted. During long time driving, temperature of the tire crown increases, while the continuously impact to the weakest section of the tire will cause tire aging to blowout. Traffic accidents caused by tire blowout in our country are increasing year by year. It plays an important part in people’s life safety. Through the quality online inspection, the personnel can trace back the reasons why the unbalance is lead in just based on the detection data and very process parameter is to be reviewed. The exploration of key technology and law of high-quality tire production will provide theory support to the structure optimization design and manufacturing process improving. At the same time, it will reduce the defective rate and pollution, and save energy, lead it to the development direction of green tire.At present, just few number of tire dynamic balance testing machines have been occupied in the domestic, even worse is that there is no equipment. There are hundreds of small tire enterprises in Shandong Province, most of them are with small scale and high defective rate. The technical equipments are very poor and weak, while the energy is wasted. Technology and equipment for detecting tire dynamic balance quality do not meet the demands of tire produce, development, testing and quality control. Furthermore, as every tire needs to be detected, so the efficiency is a major challenge for detection, especially online testing. Therefore, the research on tire dynamic balance online detection machine with high precision, high performance price ratio, high efficiency of the testing has been evoking the focus of the automobile production enterprises and tire production enterprise.Based on the on-site detection process and actual requirements, this research designs new structure of tire dynamic balance online test machine, by means of mechanical analysis, mathematical modeling, analysis and calculation software and experimental method to research the key technologies. The contents of this research mainly include:1. Two types of mechanical structure geometric model and online intelligent electrical control and solution system were put forwarded.2. According to the kinetic theory, the modal analysis of the spindle system under alternating dynamic load during the testing process was to be carried out. Both the transfer matrix method and the finite element method were adopted to calculate the critical speed and natural frequency of the lower spindle system, the upper spindle system, and the upper and lower spindle coupling system. The influence such as bearing stiffness, bearing spacing, "rim-tire" quality and external overhang length upon on the inherent critical speed and frequency was discussed. It provided guidance for the selection of measurement speed to avoid the resonance region, to ensure the safety and stability of the equipment operation.3. According to the translation equivalence principle of space force system in theoretical mechanics, the dynamic model of tire dynamic balance machine was established. Based on the testing principle, the calculation model, calibration model and eccentricity compensation model were presented. Dynamic balance measuring process is a multi variable nonlinear dynamic indirect measurement process, so the influence coefficient method was adopted. Based on the black box theory, the least square method was used to calculate the complex influence parameters. Eccentricity compensation mainly used the whole power reverse eliminate method base 2 to test even times to obtain the machine’s unbalance.4. Researched on the key factors which influenced the calculation accuracy upon the calibration coefficients. Based on the introduced "multilevel rim" and "level" measurement method, considering the effect on the tire unbalance, which the rim width brings in, the calibration model is corrected. By experimental method, the influence of key parameters concluding preloading force of sensor, measuring range and resolution of charge amplifier, weight of the adding weights on the test results has been studied. The calculation method with no tire is proposed based on the upper and lower shaft locking structure. It reduced the clamping error, eliminated tire pressure fluctuation and poor lubrication effect of bead, shorten the calibration time. This method is proved to be more stability and repeatability.5. Studied on the key technologies of the eccentric compensation process. Two types of compensation rim structure were designed. It could reduce the machine’s unbalance into an acceptable or ideal range. Based on the new compensation rim, combined with the eccentricity compensation operation and algorithm, it can obtain more exact calibration influence coefficient and system unbalance. Moreover, in view of the dislocation phenomenon of the upper and lower rim found in practice, the corrective strategy was proposed, and related electric control system was also organized.6. The wavelet threshold de-noising method called "adaptive optimal decomposition level-auto correlation threshold" was carried out. The algorithm based on the cosine window interpolation FFT was derivated. It has effectively inhibited the spectral leakage and fence effect, laying the foundation for the accurate extraction of signal characteristics.Based on a lot of field test, zero correction and MN test methods were adopted to verify the accuracy, stability and reproducibility of the measurement results. After identification, it has reached the leading domestic level. This study provides the theoretical and technical supports for design and manufacture of tire dynamic balance online testing machine, pointing out a practical and feasible way to research and development the tire dynamic balance testing machine with completely independent intellectual property rights, which showed great theoretical significance and practical application value to improve the quality of the tire in China. |
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