Drive system for a wind turbine

A drive system for a wind turbine comprising:

• a transmission unit with at least one planet wheel stage comprising a hollow wheel, several planet wheels, a planet carrier and a sun wheel,
• first shaft associated with the transmission unit and comprising a coupling flange which is mounted above the planet carrier and configured for connection to a driven machine shaft or rotor shaft,
• a gear case surrounding the transmission unit and a motor unit or generator unit connected to a second shaft of the transmission unit having a motor-side or generator-side end section,
• a rotor of the motor unit or the generator unit, connected with a rotation lock to a hollow rotor shaft which concentrically surrounds the motor-side or generator-side end section and is connected to the motor-side or generator-side end section via a coupling or clamping connection arranged inside the hollow rotor shaft, and
• a gear-case-connecting-piece which is arranged between the transmission unit and the motor unit or generator unit and concentrically surrounds a transmission-side end section of the hollow rotor shaft and forms a bearing seat for a bearing arrangement associated with the hollow rotor shaft, with the bearing seat also supporting the second shaft of the transmission unit.