Vehicle drive system.

摘要

A vehicle drive system including: a source of rotational energy (10); a flywheel (20); a first variable displacement hydrostatic unit (70); a second variable displacement hydrostatic unit (72); differential gear means (62) comprising a first drive terminal, a second drive terminal and a third drive terminal; and including means for selectable coupling of the variable displacement hydrostatic transmissions and the source of rotational energy and the flywheel to the drive wheels of the vehicle, relief valve means (116) operable between the first and second variable displacement hydrostatic units, first means for coupling in a first mode of operation (1) the flywheel and the source of rotational energy to the first drive terminal; (2) the second drive terminal to the first variable displacement hydrostatic unit; (3) the third drive terminal to the drive wheels; second means for coupling in a second mode of operation (1) the flywheel to the third drive terminal; (2) the engine (10) and the first drive terminal to the drive wheels.