Achievement of Theoretical Quantitative Evaluation Method and Effective Countermeasures for Manual Transmission Nibble

With remarkable advance achieved recently in vehicle basic performance and reliability, people are placing higher priority on human sensibility functions such as vehicle operating ease and ride comfort. As to manual transmissions, lighter and smoother gearshift feeling is in demand. Research for meeting this demand involves elaborate analysis of the phenomena that govern shift feeling and the factors of the phenomena. With conventional development methods in which designs are verified by testing, however, it is difficult to make such analysis adequately. There has thus been strong desire to apply design-stage verification development. Under this background, this study was aimed at realizing application, from early in development, of an analytical method for quantifying shift feeling. Focusing of synchronizer nibble that strongly affects smooth shift feeling, this paper discusses how equations for such design-stage verification have been formulated as well as an effective step devised to eliminate the nibble.