Patent ID: 7780563

Claim:
A drive force distribution apparatus comprising: an input shaft having a drive force receiving end and an output end; first and second output shafts disposed parallel to the input shaft; a first epicyclic gear group having two degrees of freedom, with the first epicyclic gear group including a first gear mounted on the input shaft, a second gear coupled to the first output shaft through a carrier of the first epicyclic gear group, and a third gear which is a ring gear, with the carrier of the first epicyclic gear group being disposed on a first axial side of the first gear of the first epicyclic gear group that is opposite from a second axial side of the first gear of the first epicyclic gear group where the drive force receiving end is disposed; a second epicyclic gear group having two degrees of freedom, with the second epicyclic gear group including a first gear mounted on the input shaft, a second gear coupled to the second output shaft through a carrier of the second epicyclic gear group, and a third gear which is a ring gear, with the carrier of the second epicyclic gear group being disposed on a first axial side of the first gear of the second epicyclic gear group that is opposite from a second axial side of the first gear of the second epicyclic gear group where the first epicyclic gear group is disposed, the drive force receiving end of the input shaft being disposed on the first axial side of the first gear of the second epicyclic gear group; a motor-output transmission system including first and second control pinions engaged with the third gears of the first and second epicyclic gear groups, respectively, such that the first control pinion is engaged with only the third gear of the first epicyclic gear group and the second control pinion is engaged with only the third gear of the second epicyclic gear group, a first pinion shaft fixed to the first control pinion to rotate therewith, a second pinion shaft fixed to the second control pinion to rotate therewith, the first and second control pinions being disposed on the first and second pinion shafts, respectively, and first and second middle pinions engaging each other, with the first middle pinion fixed to the first pinion shaft and the second middle pinion fixed to the second pinion shaft; and a motor/generator operatively coupled to the third gears of the first and second epicyclic gear groups so that mutually different drive forces are transmitted from the motor/generator to the first and second epicyclic gear groups, the motor/generator being attached to the first pinion shaft to rotate the first pinion shaft.