| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission ratio variable device and a vehicle steering device, capable of holding an axial direction position, regardless of the driving state of a screw shaft, in a simple structure and easy assembling.SOLUTION: This transmission ratio variable device includes the screw shaft 22 relatively non-rotatably and axially movably connected to an upper shaft 21, a ball screw nut 23 screwed with the screw shaft 22 and relatively non-rotatably and axially immovably connected to a lower shaft 20, and a driving shaft 30 capable of driving the screw shaft 22 in an axial direction. By the rotation of the ball screw nut 23 according to axial movement of the screw shaft 22, the rotation of the upper shaft 21 is increased or decreased in speed to be transmitted to the lower shaft 20, and thereby a transmission ratio between both of the upper shaft 21 and the lower shaft 20 can be varied. In the transmission ratio variable device, a pair of coil springs 50 and 51 are provided at both ends of the screw shaft 22 to press the screw shaft 22 in the axial direction, and the screw shaft 22 is pinched between the coil springs 50 and 51. |
