Importance

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Abstract

A variable valve device changes a valve lift amount in a cylinder head. The device includes: a camshaft having plural cams with different valve lift amounts; plural rocker arms in contact with the plural cams to move a valve; a switching mechanism that couples and separates the rocker arms by oil pressure; and an oil control valve that controls the oil pressure. The switching mechanism includes a hydraulic piston moveable forward and backward to couple and separate the rocker arms. First and second oil passages extend from the oil control valve to the hydraulic piston. The first oil passage includes an oil groove through which oil is allowed to pass at a predetermined rotation phase of the camshaft. The second oil passage is closed by the hydraulic piston after the rocker arms are separated from one another along the backward movement of the hydraulic piston.

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First Claim