Valve unit and a positioning device for converting a rotary motion into a linear motion

A valve unit comprising:

• a positioning device for converting a rotary motion into a linear motion comprising,
• a valve rod,
• a drive unit configured to generate a torque,
• a drive shaft on which an eccentric is arranged,
• a coupling element comprising a slot, the valve rod being connected with the coupling element, and
• an output shaft arranged at the eccentric, the output shaft being configured to move in the slot of the coupling element,
• wherein,
• the valve rod is supported so as to be linearly movable with the coupling element between an initial position in which the valve unit is in a closed position and an end position,
• the slot comprises a guide path configured to cooperate with the eccentric, the guide path of the slot comprising an angle with a plane perpendicular to a direction of movement of the valve rod,
• the initial position of the eccentric is a position which is located, as seen in a direction of rotation, before a dead center existing for an axial movement of the output shaft, the dead center being passed during a rotational movement of the drive shaft, and
• the slot is immovably attached to the valve rod.