Variable valve control device

A variable valve control device for an internal combustion engine having an intake valve, an exhaust valve and a drive shaft, comprising:

• a rotatable and axially movable driven shaft provided with a cam having axially and radially different profile for opening and closing at least one of the intake valve and the exhaust valve, opening/closing timing of the valve being variable by adjusting angular phase of the driven shaft relative to the drive shaft and lift stroke of the valve being variable by adjusting axial position of the driven shaft;
• Angular phase control means having a drive side rotor rotating in synchronism with the drive shaft and a driven side rotor rotating together with the driven shaft but allowing the axial movement of the driven shaft, an angular phase of the driven side rotor relative to the drive side rotor being hydraulically controlled;
• and
• axial movement control means having a pressure chamber and a piston fixed with the driven shaft and axially moving in the pressure chamber, an axial movement of the piston is hydraulically controlled,
• wherein the angular phase control means and the axial movement control means are basically operative independently of each other but hydraulic pressure more than minimum operating pressure for axially moving the piston is always ready to be applied to the axial movement control means at the time when the angular phase control means actually changes the angular phase of the driven side rotor relative to the drive side rotor.