Hydraulic unit for a cylinder head of an internal combustion engine with variable gas exchange valve drive hydraulically

Proposed is a hydraulic unit (5) for a cylinder head (2) of an internal combustion engine with hydraulic variable valve gear (1). In the hydraulic unit, a high-pressure chamber (11), a medium-pressure chamber (12) and a reservoir serving as a hydraulic fluid low pressure chamber (16) are formed. The low-pressure chamber communicates via a throttle point (17, 17 ', 17' ', 17' '') with the medium-pressure chamber, wherein the throttle point by means of a displaceable valve body (19, 19 ', 19' ', 19' '') is formed and anch each position of the valve body having different large flow cross-sections.