| 摘要 |
PURPOSE:To reduce gearing noise in a system with a gear between a timing pulley and a cam shaft for the relative turn thereof through shifting in an axial direction, by using a spring for giving no backlash at the gearing portion of the gear with said pulley and cam shaft. CONSTITUTION:The subject device has a constitution wherein a cylindrical gear 3 with helical teeth on the inner periphery thereof is fitted between a timing pulley 1 and a cam shaft 2, and the outer teeth 3a and the inner teeth 3b of said gear 3 are respectively geared with the inner teeth 1a on the inner periphery of the pulley 1 and the outer teeth 2a on the outer periphery of the cam shaft 2. And the gear is moved in an axial direction by a gear drive mechanism 4 and the cam shaft 2 is turned relatively to the pulley 1, thereby changing the operation cycle of a valve. In this case, said gear 3 comprises two gear components 3c and 3d, a thrust pin 3e connecting both components 3c and 3d to each other so as to be axially slidable, and a spring 3b located between said components 3c and 3d and giving a separating force thereto. |
