Countershaft gear transmission

摘要

A countershaft gear transmission is disclosed wherein a plurality of main gears including a first main gear and a second main gear rotatably mounted to a main or output shaft, a countershaft drivingly connected to an input shaft has counter gears in constant engagement with the plurality of main gears and wherein when a low gear ratio is established the first main gear transfers power from the countershaft to the main shaft and when a high gear ratio is established the second main gear transfers power. The first main gear is formed on an outer race of a one-way clutch whose inner race is free to rotate on the main shaft. A synchronizer is coupled with the main shaft for coupling the inner race of the one-way clutch with the main shaft in all of the forward gear ratios. A disc clutch is coupled with the main shaft for coupling said second main gear with said main shaft in the high gear ratio.