| 摘要 |
PROBLEM TO BE SOLVED: To reduce the size and weight of a ball nut while avoiding the influences of alternating torque to be transmitted from a control shaft to an electric motor. SOLUTION: A driving mechanism 6 for controlling the rotation of a control shaft 32 for operating a varying mechanism depending on the operated condition of an engine comprises a ball screw shaft 45 having a ball circulation groove 49 in the outer periphery face, the electric motor 36 for granting rotating force to the screw shaft, the ball nut 46 having a pair of guide grooves 55 in the inner periphery face at front and rear positions in the axial direction for rollingly holding a plurality of balls 64 in cooperation with the ball circulation groove and adapted to linearly travel to the axial direction with the rotation of the ball screw shaft, and a link mechanism for linking the ball nut to the control shaft. Two pin holes 56, 56 are provided in the almost central positions of the ball nut in the axial direction between the guide grooves in such a manner that they passes through the pin shafts 61, 61 connected to other ends 59, 59 of the link members 48 in the direction of the diameter thereof. COPYRIGHT: (C)2004,JPO
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