Vehicle drive system

A drive system of a vehicle, comprising:

• an internal combustion engine;
• an electric motor;
• an output member that delivers power to driving wheels of the vehicle;
• a differential mechanism that includes a first element, a second element and a third element capable of differential rotation relative to each other, said internal combustion engine being coupled to the first element, said electric motor being connected to the second element;
• a transmission mechanism that establishes a plurality of gear positions that are set stepwise in decreasing order of a gear ratio over a range from the differential mechanism to the output member, by switching among first change gear trains interposed between the first element of the differential mechanism and the output member for transmitting power from the first element to the output member or by switching among second change gear trains interposed between the third element of the differential mechanism and the output member for transmitting power from the third element to the output member, and coupling the first element to the output member without involving any of the change gear trains;
• and
• a differential lock mechanism that switches the differential mechanism between a locked state in which selected two of the first element, the second element and the third element of the differential mechanism are coupled to each other so as to be inhibited from differential rotation, and a released state in which the inhibition of the differential rotation is cancelled, wherein
• the electric motor comprises a stator, and a rotor that is disposed coaxially with the stator and has a space formed radially inside thereof;
• the differential mechanism is placed in the space formed radially inside the rotor;
• and
• the differential lock mechanism is located at a posit on remote from the differential mechanism in an axial direction.