Patent ID: 8402933

Claim:
A rocker arm changeover device for an engine, comprising: at least one major rocker arm to drive a plurality of intake valves or a plurality of exhaust valves; at least one driven rocker arm arranged in line with the major rocker arm; and a changeover pin that is movable within a first pin hole and a second pin hole to change an engagement state of the major rocker arm and the driven rocker arm between engagement and disengagement, the first pin hole being provided in the major rocker arm and the second pin hole being provided in the driven rocker arm at positions such that the first pin hole in the major rocker arm coaxially matches the second pin hole in the driven rocker arm through rocking motions of the major rocker arm and the driven rocker arm, the changeover pin comprising: a first pin being movable within the first and second pin holes between two positions including a position of the disengagement at which the first pin is retracted into the first pin hole in the major rocker arm, and a position of the engagement at which the first pin protrudes from the major rocker arm; and a second pin being movable relative to the first pin within the first pin hole in the major rocker arm coaxially with the first pin, the second pin and the first pin having mutually overlapping portions within movable ranges of the first pin and the second pin, the second pin having a smaller diameter than the first pin, the first pin having a second-pin support hole into which part of the second pin is receivable to allow the second pin to protrude from the second-pin support hole and be retracted into the second-pin support hole, the first pin having an oil path through which a hydraulic pressure is supplied to the second-pin support hole, the first pin being moved with respect to the major rocker arm to protrude from the major rocker arm in a direction in which the first pin is separated from the second pin when the hydraulic pressure is supplied to the second-pin support hole.