US Patent 10421350 Inline electromechanical variable transmission system

A drive system includes a first gear set and a second gear set, each having a sun gear, a ring gear, a plurality of planetary gears coupling the sun gear to the ring gear, and a carrier rotationally supporting the plurality of planetary gears; a connecting shaft coupling an engine to the first gear set; a first electrical machine coupled to the first gear set; a second electrical machine coupled to the second gear set; an output shaft configured to transport power from the first electrical machine, the second electrical machine, and the engine to a tractive element; and a clutch selectively rotationally coupling the first carrier to the output shaft when engaged. The output shaft is aligned with the connecting shaft, the first electrical machine, and the second electrical machine to thereby form a straight-thru transmission arrangement.