Patent ID: 8051817

Claim:
A variable valve mechanism ( 10 ), comprising: a camshaft ( 12 ) including a drive cam ( 14 ); a rocker shaft ( 25 ) provided parallel to the camshaft ( 12 ); and a variable mechanism ( 30 ) that is provided on the rocker shaft ( 25 ) and interposed between the drive cam ( 14 ) and a valve ( 13 ), and that changes an opening/closing amount of the valve ( 13 ), wherein the variable mechanism ( 30 ) includes a main arm ( 35 ) that is swingably supported by the rocker shaft ( 25 ), and engages with the drive cam ( 14 ), a cam arm ( 40 ) that is swingably supported by the rocker shaft ( 25 ), and has a cam surface ( 41 ) pressing the valve ( 13 ), a control cam ( 31 ) that is provided on the rocker shaft ( 25 ), and has an outer peripheral surface ( 32 ) whose distance from a shaft center ( 26 ) of the rocker shaft ( 25 ) varies gradually, and a displacement member ( 48 ) that is connected to the main arm ( 35 ) and the cam arm ( 40 ) through a connection member ( 46 , 47 ) and is in contact with the control cam ( 31 ), wherein a distance between the displacement member ( 48 ) and the shaft center ( 26 ) is changed by turning of the control cam ( 31 ), and wherein a relative phase between the main arm ( 35 ) and the cam arm ( 40 ) is displaced as the distance between the displacement member ( 48 ) and the shaft center ( 26 ) changes.