摘要 |
A countershaft transmission includes an input shaft, a countershaft, an output shaft, first and second disc type directional clutches associated with the input shaft, and disc type speed clutches associated with the countershaft and output shaft to selectively connect a plurality of constantly meshing gears in preselected patterns to provide three forward speeds and three reverse speeds for a work vehicle such as a track-type tractor. The gears and clutches are functionally arranged in a forward and reverse mechanism serially connected to a three-speed mechanism and a speed reduction ratio change can be made to the speed mechanism without effecting the speed reduction ratio of the forward and reverse mechanism. Reverse speeds greater than 20% faster than the corresponding forward speeds are possible using a three-gear train in the forward and reverse mechanism. The gears, and the directional and speed clutches are arranged to provide a radially and longitudinally compact transmission.
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