System For Opening And Closing A Flap

A system for opening and closing a flap for a motor vehicle, the flap being mounted along one of its edges at a stationary structural component of the motor vehicle for swiveling movement around a swiveling axis between a closed position and an open position, the system comprising:

• a single first non-self-locking drive device coupled between the flap and the stationary structural component, the single first non-self-locking drive device being an electromechanical drive device, the single first non-self-locking drive device comprising:
• a tubular housing that is closed at one end by a base piece;
• a first connecting element coupled to the base piece;
• a second connecting element arranged at a second end of the tubular housing opposite the closed end;
• a rotary drive arranged inside the housing proximate to the closed end;
• and
• a spindle configured to be driven by the rotary drive to axially change a distance between the first and the second connecting elements;
• and
• a single second drive device acting in parallel with the first drive, the second drive device being one of a hydraulic, pneumatic, and hydropneumatic drive device, the second drive device comprising:
• a cylinder having a first closed end articulated at one of the stationary structural component and the flap at a distance from the swiveling axis, the cylinder being at least partially filled with a fluid under pressure;
• a piston that divides an interior of the cylinder into a first work chamber and a second work chamber;
• an axially extending groove formed in the cylinder proximate to the first closed end and configured to increase fluid flow when the piston approaches the closed end of the cylinder;
• a piston rod having a first end coupled to the piston, a second end of the piston rod being guided outward through and out of the first work chamber and articulated at the other of the flap or the stationary structural component at a distance from the swiveling axis;
• a sealing and guiding package adapted to guide the piston rod through and out of the first work chamber;
• a valve arrangement forming a fluid flow connection between the first work chamber and the second work chamber;
• wherein the valve arrangement is closed when the flap is stationary, and
• wherein the single first drive device is arranged at a first edge area of the flap and the single second drive device is arranged at a second edge area of the flap opposite the first edge area of the flap, each edge area extending at substantially a right angle from the swiveling axis,
• whereby the fluid flow, as the flap enters and exits the closed position, bypasses the valve arrangement via the axially extending groove;
• a first spring receiving part arranged at the second end of the piston rod;
• a second spring receiving part arranged at the closed end of the cylinder;
• and
• a spring arranged coaxially with respect to the housing between the first and the second spring receiving parts.