Variable valve device

A variable valve device configured to change a valve lift amount in a cylinder head, the variable valve device comprising:

• a camshaft formed with a plurality of cams having different valve lift amounts;
• a plurality of rocker arms configured to be in contact with the plurality of cams and move a valve;
• a switching mechanism configured to couple and separate the plurality of rocker arms by oil pressure;
• and
• an oil control valve configured to control the oil pressure applied to the switching mechanism,
• wherein the switching mechanism includes a hydraulic piston configured to be moved forward and backward by the oil pressure such that the plurality of rocker arms are coupled along forward movement of the hydraulic piston, and the plurality of rocker arms are separated along backward movement of the hydraulic piston,
• wherein a first oil passage and a second oil passage extend from the oil control valve to the hydraulic piston,
• wherein a part of the first oil passage is formed by an oil groove through which oil is allowed to pass at a predetermined rotation phase of the camshaft,
• wherein the second oil passage is opened during forward movement of the hydraulic piston and is closed during backward movement of the hydraulic piston, and
• wherein a bypass passage configured to bypass the oil groove when the second oil passage is closed is provided.