| 摘要 |
PURPOSE: A variable valve mechanism is provided to prevent the height rise of the cylinder head because the relative phase of the main arm and the cam arm is changed by the distance change between the displacement member and the axial center of the rocker shaft. CONSTITUTION: A variable valve mechanism comprises a cam shaft(12), a rocker shaft(25), and a variable mechanism(30). The variable mechanism includes a main arm which is supported against the rocker shaft and engaged with a drive cam(14), a cam arm(40) which is supported against the rocker arm and has a cam surface(41) pressing a valve(13), a control cam(31) which is installed on the rocker shaft and has an outer section(32) varying the distance from the axial center(26) of the rocker shaft, and a displacement member(48) which is connected to the main arm and the cam arm through connecting members(46,47) and contacts the control cam. The distance between the displacement member and the axial center is varied by the motion of the control cam, and therefore the relative phase of the main arm and the cam arm is changed.
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