F2010C011
Examination of Manual Transmission Gear Jump Out Behavior
In a manual transmission at the prototype development stage, the sleeve can come off of the gear piece during running. This phenomenon is called "gear jump out" and it unusually causes a problem in which the drive force is not transmitted during running. In order to solve this problem the mechanism that causes gear jump out needs to be fully understood. However, gear jump out is a behavior wherein the amount of jump out increases gradually every other rotation. Up until now this has made it very difficult to clarify the gear jump out phenomenon by analyzing the behavior of the components. Therefore, the changes in the behavior of the gear piece, sleeve, and hub over time were clarified using dynamic structural analysis and experimentation in order to reveal the mechanism that causes gear jump out to occur. First, the gear jump out behavior was reproduced using dynamic structural analysis. Then, the gear piece and sleeve behavior with reference to the position of the hub were confirmed to qualitatively match the experimentation results. Next, the friction force generated during one rotation between the spline tooth surfaces of the sleeve and hub was calculated and compared to the critical friction force. As a result, it was found that the friction force between the spline tooth surfaces of the sleeve and hub reached the critical friction force during one rotation, which caused relative displacement of the sleeve and hub, and this indicates that gear jump out behavior or gear jump in behavior is present. On the other hand, it was found that in the regions where the friction force does not reach the critical friction force, that gear jump out behavior and gear jump in behavior are not present. Based on the above, it was found that when a region of no relative displacement exists within the gear jump in region, then gear jump out advances every other rotation. Furthermore, it was found that because the spline tooth surface pressure between the sleeve and hub becomes high in the gear jump in region, that the critical friction force increases and so the friction force does not reach the critical friction force. Consequently, a region of no relative displacement exists within the gear jump in region.
This abstract is supplemented by a PDF, which can be viewed here.
Session: Testing and Simulation of Vehicle and Component Dynamics