Track-laying vehicle electric drive system

An electrical drive system for vehicles comprising, in combination:

• A. a first electric motor for developing a first variable speed, bidirectional output;
• B. a second electric motor for developing a second variable speed, bidirectional output;
• C. a third electric motor for developing a third variable speed output;
• and
• D. a transmission including
• 1) a left output shaft drivingly connected to one vehicle track,
• 2) a right output shaft drivingly connected to the other vehicle track,
• 3) a left combining gear set having a first gear element driven by a said first output, a second gear element drivingly connected with said left output shaft, and a third gear element,
• 4) a right combining gear set having a first gear element driven by said second output, a second gear element drivingly connected to said right output shaft, and a third gear element,
• 5) a cross shaft for commonly applying said third output to said third gear elements of said left and right combining gear sets, and
• 6) a brake operating to ground said third gear elements of said left and right combining gear sets to provide low range vehicle propulsion and steer, and with said third electric motor energized, said brake disengaged to release said third gear elements of said left and right combining gear sets to provide, in combination with said first and second electric motors, high range vehicle propulsion and steer.