Hydro-mechanical transmission

A hydro-mechanical transmission comprising:

• an input shaft adapted to be connected to a rotational power source;
• an output shaft adapted to be connected to a load;
• a hydrostatic unit driven by the input shaft and having an output;
• a mechanical transmission having a planetary gear system including first and second planetary gear sets including a pair of sun gears (S1) and (S2), a ring gear (R2), the sun gear (S1) being driven by the input shaft, the ring gear (R2) being driven by the hydrostatic unit output while the carrier is selectively coupled to the output shaft through a low range clutch and the sun gear (S2) is selectively coupled to the output shaft through a high range clutch to provide two forward speed ranges.

A hydro-mechanical transmission comprising:

• an input shaft adapted to be connected to a rotational power source;
• an output shaft adapted to be connected to a load;
• a hydrostatic unit driven by the input shaft and having an output;
• a mechanical transmission having a planetary gear system, the mechanical transmission having a pair of input elements with one input element coupled to the hydrostatic unit output to be driven thereby and one input element coupled to the input shaft and continuously driven thereby, the mechanical transmission combining the two inputs into a single hydro-mechanical power output, the mechanical transmission having a planetary system with three planetary gear sets including a reversing planetary gear set, a low range clutch, a high range clutch and a reverse brake whereby the transmission has two forward speed ranges and one reverse speed range for infinitely variable speed adjustment between a full speed reverse and a full speed forward.