Variable valve operating mechanism

A variable valve operating mechanism comprising:

• two valve operating members for opening and closing two valves individually;
• a drive cam provided on a single camshaft;
• two swing arms for transmitting a power of the drive cam to the valve operating members individually by swinging about a different axis to the camshaft;
• and
• a variable device for modifying a displacement of the swing arm per rotation of the drive cam in accordance with an operating condition of the internal combustion engine, the variable device comprising:
• a single control shaft;
• an actuator for driving the control shaft;
• and
• a cam device that operates in conjunction with the control shaft to dissimilate the displacement of the two swing arms,
• wherein the cam device comprises two variable cams for driving the two swing arms individually, and the two variable cams are provided on the control shaft and are provided with cam surfaces having respectively different profiles,
• wherein, in a first rotation section of the control shaft, each of the cam surfaces of the two variable cams comprises the maximum lift portion at which the respective valves reach a maximum lift, and
• wherein in a second rotation section of the control shaft, which is adjacent to the first rotation section, the cam surface of one of the variable cams comprises continuous maximum lift portions for maintaining the maximum lift of the valve, and the cam surface of the other variable cam comprises a gradually decreasing lift portion for continuously decreasing the lift of the valve.