Development of quantitative evaluation method of differential units

摘要

Reflecting on differential gear noise issue in many past projects, quantitative evaluation method is required as an alternative of conventional visual hypoid gear tooth contact check so as to improve customer satisfaction in our differential units supply business. In starting a new unit business, we have installed a device for judging and recording the tooth contact by in-line image processing as 100% inspection. This technology was developed in hypoid gears processing field and there was some problems in applying it to assembly lines caused by inaccuracy by human error and by line space limitation etc. After the problems were cleared up through some steps with equipping and improving a prototype device, installed and improved in out-line, this technology was applied to mass-production. By this technology, the tooth contact check, which is a component parts property, has been advanced as a quantitative evaluation method for a complete quality assurance. In addition, the torsional vibration tester is being installed as a quantitative evaluation method for functional property assurance. Torsional vibration can be measured at high speed, and measuring accuracy can be improved by a larger number of sampling. We have recognized correlation between interior noise and the torsional vibration, and judged it possible to assure unit noise by using this functional property. This report introduces these two quantitative evaluation methods as differential unit quality assurance.