Driving device

1. A driving device for a vehicle, comprising:

an internal combustion engine;

a first rotating electric machine;

a second rotating electric machine; and

a transmission, wherein:

the transmission includes:

a first rotating electric machine shaft which is a rotating shaft of the first rotating electric machine;

a second rotating electric machine shaft which is arranged in parallel to the first rotating electric machine shaft and is a rotating shaft of the second rotating electric machine;

a first gear provided in the first rotating electric machine shaft; and

a second gear provided in the second rotating electric machine shaft;

a width in an axial direction of the first rotating electric machine is larger than a width in the axial direction of the second rotating electric machine;

the number of gears provided in a shaft in which a gear for the first rotating electric machine that meshes with the first gear is arranged is smaller than the number of gears provided in a shaft in which a gear for the second rotating electric machine that meshes with the second gear is arranged;

the shaft in which the gear for the first rotating electric machine is arranged is the input shaft to which a driving force from the internal combustion engine is inputted;

the shaft in which the gear for the second rotating electric machine is arranged is the counter shaft provided with an output gear that transmits the driving force from the internal combustion engine and a driving force from the second rotating electric machine to an output shaft;

the input shaft is provided with a first drive gear that transmits the driving force from the internal combustion engine to the counter shaft; and

the first drive gear is arranged at a location closest to the internal combustion engine among power transmission elements provided in the input shaft.

2. The driving device according to claim 1 , wherein

the second gear is arranged at a location closest to the second rotating electric machine among power transmission elements provided in the second rotating electric machine shaft.

3. The driving device according to claim 1 , wherein:

the input shaft is further provided with a second drive gear that transmits the driving force from the internal combustion engine to the counter shaft;

the counter shaft is further provided with a second driven gear driven by the second drive gear;

the gears provided in the input shaft are the first drive gear, the gear for the first rotating electric machine, and the second drive gear; and

the gears provided in the counter shaft are the gear for the second rotating electric machine, the second driven gear, the output gear, and a first driven gear driven by the first drive gear.

4. The driving device according to claim 3 , wherein

a first gear train including the first drive gear and the first driven gear has a reduction ratio larger than that of a second gear train including the second drive gear and the second driven gear.

5. The driving device according to claim 3 , wherein:

the input shaft is further provided with a first connecting and disconnecting mechanism capable of connecting and disconnecting a power transmission path from the input shaft to the first drive gear;

from the side closest to the internal combustion engine, the first drive gear, the first connecting and disconnecting mechanism, the gear for the first rotating electric machine, and the second drive gear are arranged in this order in the input shaft;

a diameter of the gear for the first rotating electric machine is larger than a diameter of the first connecting and disconnecting mechanism; and

the gear for the first rotating electric machine and the first connecting and disconnecting mechanism partially overlap each other in the axial direction.

6. The driving device according to claim 3 , wherein

the counter shaft is further provided with a second connecting and disconnecting mechanism capable of connecting and disconnecting a power transmission path from the second driven gear to the counter shaft.

7. The driving device according to claim 1 , wherein

the gear for the second rotating electric machine is arranged at a location closest to the second rotating electric machine among power transmission elements provided in the counter shaft, and overlaps the first rotating electric machine in the axial direction.

8. A driving device comprising:

an internal combustion engine;

a first rotating electric machine;

a second rotating electric machine; and

a transmission, wherein:

the transmission includes:

an input shaft to which a driving force from the internal combustion engine is inputted;

a differential device connected to an output shaft;

a counter shaft that transmits the driving force from the internal combustion engine and a driving force from the second rotating electric machine to the differential device;

a first rotating electric machine shaft which is a rotating shaft of the first rotating electric machine; and

a second rotating electric machine shaft which is a rotating shaft of the second rotating electric machine;

the input shaft, the counter shaft, the first rotating electric machine shaft, the second rotating electric machine shaft, and the output shaft are arranged in parallel to each other; and

when viewed from an axial direction, a shaft center of the input shaft and a shaft center of the counter shaft are arranged in a virtual triangle formed by connecting a shaft center of the first rotating electric machine shaft, a shaft center of the second rotating electric machine shaft, and a shaft center of the output shaft.

9. The driving device according to claim 8 , wherein:

when viewed from the axial direction, the shaft center of the second rotating electric machine is located closer to the shaft center side of the output shaft than the shaft center of the first rotating electric machine, and is located closer to the shaft center side of the first rotating electric machine than the shaft center of the output shaft; and

a part of the second rotating electric machine is located below a virtual line formed by connecting an uppermost portion of the first rotating electric machine and an uppermost portion of the differential device.

10. The driving device according to claim 8 , wherein:

the input shaft includes:

a first drive gear that transmits the driving force from the internal combustion engine to the counter shaft; and

a gear for the first rotating electric machine that is provided in the input shaft, and transmits the driving force from the internal combustion engine to the first rotating electric machine shaft;

the counter shaft includes:

a first driven gear driven by the first drive gear;

a gear for the second rotating electric machine that is driven by the driving force from the second rotating electric machine; and

an output gear that transmits the driving force from the internal combustion engine and the driving force from the second rotating electric machine to the output shaft;

the first drive gear and the gear for the first rotating electric machine partially overlap the first rotating electric machine when viewed in the axial direction; and

the first driven gear, the gear for the second rotating electric machine, and the output gear partially overlap the second rotating electric machine when viewed from the axial direction.

11. The driving device according to claim 10 , wherein

the first drive gear and the gear for the first rotating electric machine partially overlap the first rotating electric machine and the second rotating electric machine when viewed from the axial direction.