| 摘要 |
PURPOSE: To reduce the driving force of a cam in a valve system of an internal combustion engine including a rocker arm, the turning fulcrum position of which is changed to change the lift timing of a valve. CONSTITUTION: Rollers 10, 13 are installed in at least one of contact places in a driving force transmitting path extending from a cam 9 as a driving source to a valve 1 to make the contact into rolling contact. Thus, a first rocker arm can be oscillated by light force, so that even if the number of cylinders of an internal combustion engine is increased, small cam driving force is enough. One 12-1 of contact surfaces in the driving force transmitting path is a circular- arc surface taking the center of the cam as the center. Though the relationship between the lift amount of the valve and the lift timing is changed by moving the position of the turning fulcrum 15C of a second rocker arm 12 in the direction of an arrow A or B, if the cam is a circular-arc surface, at the time of change, the position of the rocker arm 6 will not be changed. |
