| 摘要 |
PURPOSE:To prevent occurrence of excessive thrust force during normal drive operation by arranging a first cam surface formed in one of input and output members and a second cam member so that they are inclined in parallel with each other, and by clamping rollers between both cam surfaces by the compression force of compression spring. CONSTITUTION:First and second cam rollers 10, 11 are held between first and second cam surfaces 12a, 13a being clamped therebetween by the compression force of a compression spring 17. Accordingly, even though torque abruptly varies from a normal drive condition to a reverse drive condition, the cam surfaces 12a, 13a and the cam rollers 10, 11 which make contact with each other never separate from each other. Further, the compression force of a compression spring 17 has a function ensuring a minimum thrust force with which a V-belt is not loosed during reverse drive operation. Further during normal drive operation since no more than the compression force of the compression spring 17 is added to the thrust force transmitted from the first cam roller 10 to the first cam surface 12a, no twist torque component which has been essential in the conventional arrangement is added, thereby there is no fear of excessive force effected during normal drive operation.
|
