| 摘要 |
PROBLEM TO BE SOLVED: To freely rotate a steering wheel using a small-size and lightweight clutch of a simple constitution, even if an electric motor and a steering control system break down. SOLUTION: This electric power steering device 10 is provided with a clutch 40 allowing only the transmission of the rotating force from the electric motor 20 to a nut 27 between the electric motor 20 and the nut 27 of a ball screw device 25. The clutch 40 is provided with a driving plate 41 integrally rotating with the electric motor 20, a driven plate 43 integrally rotating with the nut 27, and an intermediate plate 42 axially displacing with its clamped between the driving plate 41 and the driven plate 43. A ball 53 is interposed between ball cramping faces 51A and 52A of the opposed driving plate 41 and the intermediate plate 42, the interval between the ball cramping faces 51A and 52A is made to gradually approach radially outward, and a ball collision part 51B collided with the ball 53 in the rotating direction of the driving plate 41 is formed in the ball clamping face 51A of the driving plate 41. |
