Patent ID: 8118003

Claim:
A valve operating system of an engine which is configured to change lift characteristics of a valve for opening and closing a port for air-intake or for air-exhaust, comprising: a drive cam provided at a camshaft which is configured to rotate in association with a crankshaft; and a pivot cam mechanism which is provided between the drive cam and the valve; wherein the pivot cam mechanism includes: a pivot member which is angularly displaceably supported by a first support shaft and includes a pressing portion which is configured to press the valve by the angular displacement of the pivot member around the first support shaft, the pivot member causing the valve to reciprocate; and a driven member which is angularly displaceably supported by a second support shaft provided at the pivot member eccentrically from the first support shaft and radially outward relative to and away from the first support shaft and has a sliding contact surface which is configured to slidably contact the drive cam, the driven member being configured to transmit displacement of the drive cam to the pivot member; and wherein the pivot cam mechanism causes the driven member to be angularly displaced around the second support shaft to change relative attitudes of the driven member and the pivot member and causes the pivot member and the driven member to be integrally pivoted around the first support shaft according to rotation of the drive cam.