Patent ID: 8727924

Claim:
A drive force output apparatus for a vehicle, comprising: a drive source that outputs a drive force; at least two motor generators, which include a first motor generator and a second motor generator; and a drive force transmission device that has at least two planetary gear mechanisms, which include a first planetary gear mechanism and a second planetary gear mechanism; an electric power source that is adapted to supply an electric power to or receive an electric power from the first motor generator and the second motor generator; and control means for controlling the drive source, the first motor generator and the second motor generator, wherein: a drive force input shaft is connected to an output shaft of the drive source to conduct the drive force between the drive force input shaft and the output shaft of the drive source; a drive force output shaft is connected to a wheel of the vehicle to conduct a drive force between the drive force output shaft and the wheel of the vehicle; the drive force input shaft, a rotatable shaft of the first motor generator, a rotatable shaft of the second motor generator and the drive force output shaft are connected with each other through the drive force transmission device to conduct a drive force therebetween; a planetary ratio of the first planetary gear mechanism and a planetary ratio of the second planetary gear mechanism are set such that all of the following values become equal to each other: a maximum value of a drive force of the first motor generator, which is generated when a total input-to-output speed ratio between a rotational speed of the drive force input shaft and a rotational speed of the drive force output shaft is a first predetermined value upon operation of the first motor generator as an electric motor; a maximum value of a drive force of the first motor generator, which is generated when the total input-to-output speed ratio is a second predetermined value that is larger than the first predetermined value upon operation of the first motor generator as the electric motor; and a maximum value of a drive force of the first motor generator, which is generated when the total input-to-output speed ratio is in a range from the first predetermined value to the second predetermined value upon operation of the first motor generator as an electric generator; and the control means controls the first motor generator and the second motor generator according to a demanded output of the drive force output shaft.