Patent ID: 7325522

Claim:
Valve drive for a cam-operated valve of an internal combustion engine, in which the valve is loaded by a closing force against an opening direction of the valve by a valve spring, the valve drive comprising a hydraulic force application device, with which a force can be applied directly or indirectly against a direction of the closing force onto the valve, the force application device including a piston moveable in a displacement direction (R) relative to a cylinder of the force application device through introduction of hydraulic fluid into a pressure chamber formed between the piston and the cylinder, wherein the piston can be moved relative to the cylinder from a first end position (A) into a second end position (B), a braking or damping system to brake movement of the piston relative to the cylinder from when a predetermined relative position is reached between the piston and the cylinder until one of the end positions is reached, the braking or damping system is formed by a braking piston, which is supported so that it can move relative to the piston in the displacement direction and can be moved relative to the cylinder in the displacement direction, wherein an oil chamber is formed between the piston and braking piston, which is sealed from the pressure chamber formed between the piston and cylinder, and a closing element, which open a fluid opening after a predetermined displacement of the braking piston relative to the cylinder is exceeded and close the fluid opening again after falling below the predetermined displacement, whereby a fluid connection can be created or blocked between the pressure chamber formed between the piston and the cylinder and the oil chamber.