Torque transmission unit, drive train and method for operating a torque transmission unit

A drive train for a motor vehicle, comprising:

• an internal combustion engine;
• an electric machine;
• transmission unit;
• and
• a torque transmission unit including a first input side mounted rotatably about an axis of rotation, a second input side, an output side, a hydrodynamic converter, a lock-up clutch, and a freewheel,
• the first input side being connected to the internal combustion engine in a torque-locking manner, a first to be introduced to the first input side via the internal combustion engine;
• the second input side being connected to the electric machine in a torque-locking manner, a second torque being introduced to the second input side via the electric machine;
• the output side being connected to the transmission unit in a torque-locking manner;
• and
• the lock-up clutch being parallel to e hydrodynamic converter;
• wherein the freewheel is downstream of the hydrodynamic converter, and the second input side is downstream of the freewheel in a torque flow of the first torque from the first input side to the output side;
• wherein the freewheel is selectively operatable between a first freewheel operating state and a second freewheel operating state,
• wherein the freewheel is designed to connect torque-locking manner, the hydrodynamic converter to the output side in the first freewheel operating state of the freewheel to transmit the first torque from the first input side to the output side when the lock-up clutch is open;
• wherein the freewheel is designed to decouple the hydrodynamic converter from the output side in the second freewheel operating state to at least partially prevent torque transmission of the second torque from the second input side to the hydrodynamic converter.

A method for operating a torque transmission unit comprising:

• operating a first input side at a first speed;
• introducing a torque into the torque transmission unit via a second input side, wherein the second input side is operated at a second speed that is sent from the first speed;
• wherein a difference between the first speed and the second speed is smaller than a predefined speed difference;
• wherein a lock-up clutch is open;
• operating a freewheel in a freewheel operating state that at least partially interrupts a torque transmission of the torque from the second input side to a hydrodynamic converter;
• wherein the torque is transmitted to an output side.