Transmission system coupling device and fan

The invention provides a transmission system coupling device, and relates to the technical field of fan systems, the front end of a main shaft is used for connecting a fan blade hub, the outer diameter of the front end of the main shaft is larger than that of the rear end of the main shaft, the rear end of the main shaft is fixed to a flange plate, and a wind wheel locking plate and a gearbox rotating stand are fixedly connected to the flange plate; the wind wheel locking device is installed on the main machine frame, and when parking is needed, a lock rod arranged on the wind wheel locking device moves in the axial direction of the main shaft so as to be inserted into a lock pin hole formed in the wind wheel locking disc, the main shaft is prevented from rotating, and parking is achieved. The wind wheel locking disc is arranged at the rear end of the main shaft, compared with the mode that the wind wheel locking disc is arranged at the front end, the size and the weight of the wind wheel locking disc can be