Patent ID: 7669691

Claim:
A steering device for a vehicle, comprising: a transmission ratio variable mechanism which can mechanically vary a transmission ratio between a steering angle of a steering member and a turning angle of turning wheels, an electric motor including a rotor which can rotate integrally with a determined element in an annular shape of said transmission ratio variable mechanism, and provided for varying the transmission ratio, a controller connected and adapted to control said electric motor to vary the transmission ratio between the steering angle of the steering member and the turning angle of turning wheels, and a lock mechanism for fixing said transmission ratio when an abnormal condition has occurred, wherein said lock mechanism includes a restraining member which is engageable with said determined element or an annular member which is integrally rotated with said determined element, whereby rotation of said determined element can be restrained, wherein said transmission ratio variable mechanism includes a first sun gear connected to the steering member, a second sun gear having an axis corresponding to an axis of the first sun gear and connected to the turning wheels, a planet gear which is meshed with the first and second sun gears, and a carrier in an annular shape which supports the planet gear so as to rotate on an axis thereof and so as to revolve around the axis of the first and second sun gears integrally, wherein said determined element includes said carrier.