VARIABLE VALVE MECHANISM FOR ENGINE

A variable valve apparatus for an engine is provided to manufacture a cylinder head of the engine with compact structure, and to relieve stress by switching cams with a coil spring and hydraulic pressure of engine oil. An engine comprises a rocker shaft(7) arranged in a cylinder head, a cam shaft(8) arranged in the cylinder head in parallel with the rocker shaft, placed in an upper part of the rocker shaft and composed of a first cam(9a) and a second cam(9b), a first rocker arm(15) turned, supported to the rocker shaft and driven by the first cam to transmit displacement of the first cam to a valve, and a second rocker arm(20) arranged in parallel with the first rocker arm, turned and supported to the rocker shaft and driven by the second cam. A variable valve apparatus(V) is composed of a switching unit(30) selectively transmitting displacement of the second rocker arm to the first rocker arm, and the switching unit is installed at a side of the cam shaft. The switching unit comprises a first contact part(31) mounted in the first rocker arm, a second contact part(40) mounted in the second rocker arm and opposed to the first contact part corresponding to turning direction around the rocker shaft, and a switching element(36) mounted in the contact part, contacted to the other contact part and displaced between the first position transmitting displacement of the second rocker arm to the first rocker arm and the second position not to be contacted to the other contact part.