Synchronizer re-energization for improved cold shift comfort

摘要

A synchronizer mechanism for synchronizing the rotation of gears between a power input shaft and a power output shaft in a manual transmission includes a hub and a synchronizer sleeve disposed about the hub and moveable relative thereto into and out of engagement with adjacent gears to synchronize the rotation of the adjacent gears with the rotation of the power input shaft. An indexing mechanism is employed for indexing the synchronizer sleeve into and out of engagement with adjacent gears. The indexing mechanism includes a retaining mechanism and a detent portion having a main synchronization detent and at least one second synchronization detent disposed laterally adjacent the main synchronization detent. The main synchronization detent causes an intermediate clutch ring to contact a cylindrical cone portion on a gear and begin the change in angular velocity of the gear and to begin the synchronization sequence of the mechanism at a first time. The second synchronization detent causes the intermediate clutch ring to contact a cylindrical cone portion on a gear and change the angular velocity of the gear and synchronizer mechanism at a second time reducing the minor speed difference between the gear and synchronizer sleeve caused by loss of synchronization between the time of sleeve and ring indexing and initial engagement contact of the sleeve to the clutch teeth of the gear.