VALVE GEAR FOR ENGINE

PROBLEM TO BE SOLVED: To perform switching to an optimum valve timing according to the low rotation, middle rotation or high rotation of an engine.SOLUTION: A camshaft phase variable device 40 includes: a first driven member 41 which is relatively rotatable to an intake-side camshaft 34 by transmitting rotation of a crankshaft thereto; a second driven member 42 which is displaceable in the rotating direction and axial direction relative to the first driven member; a guide member 43 which is provided to be rotatable integrally with the camshaft, and is relatively displaceable in the rotating direction and axial direction relative to the second driven member; a first centrifugal weight 44 disposed between the first driven member and the second driven member; a second centrifugal weight 45 disposed between the second driven member and the guide member; and a biasing member 46 which biases the first and second driven members and the guide members in an approaching direction. The second driven member and the guide member are moved by a centrifugal force acting on both the centrifugal weights and relatively displaced in the rotating direction and axial direction relative to the first driven member to displace the rotating directional phase of the camshaft relative to the crankshaft.