Hydro-mechanical transmission

摘要

A hydro-mechanical transmission having a planetary system with three planetary gear sets including a reversing planetary gear set together with two clutches and a reverse brake to provide an infinitely adjustable speed change over the speed range from -20 kph to 60 kph without an additional direction change gear set. The transmission has two forward speed ranges and one reverse speed range. The planetary system has fixed mechanical and hydrostatic power input elements and a fixed output element. The low and high range clutches and the reverse brake direct power flow through the transmission along different paths to produce the different gear ratios. Transmission efficiency is maximized at the field use speed and the transport road speed where an agricultural tractor is most often operated.