Patent ID: 7950481
Filing Date: 2011-05-31
Classification: B60K,B60L,B60Y,Y02T

Abstract:
1. A track-type tractor having an electric drive system comprising: an engine configured to provide rotational energy and an electrical generator configured to receive the rotational energy from the engine and to thereby produce electrical energy; at least one electric motor having a rotational output lying on an output axis, for receiving electrical energy from the generator and thereby producing output rotational energy at the rotational output, wherein the at least one electric motor is a liquid-cooled electric motor; at least one power electronics unit configured to control an output of the at least one electric motor, wherein the at least one power electronics unit is liquid cooled; a differential steering unit operably coupled to the at least one electric motor, the differential steering unit having a first output linked to a first driving member and a second output linked to a second driving member, the first and second outputs being axially aligned with one another and with a central axis of the differential steering unit, wherein the central axis of the differential steering unit is non-coaxial with the output axis of the at least one electric motor; a hydraulic steering motor operatively coupled to the differential steering unit to cause the differential steering unit to selectively control an amount of torque supplied to each of the first and second driving members; and an electric energy storage system configured to receive energy from the at least one electric motor during deceleration of the tractor, the storage system further being configured to provide energy to the at least one electric motor in addition to energy produced by the generator to prevent the engine from lugging or stalling.