Constant-tension cable reel

The invention relates to a constant-tension cable reel, which comprises a motor, a speed reducer, a permanent magnet damper, a reel body, a collecting ring, a V-shaped belt and a hand wheel and is characterized in that the speed reducer is arranged in the reel body; the motor is arranged at the lower part of the reel body; the permanent magnet damper is arranged between an input shaft of the speed reducer and an output shaft of the motor; and the output shaft of the speed reducer is directly connected with the reel body. The invention has the advantages of reducing the volume of the entire machine, saving the space and simplifying the structure. The hand wheel is arranged on one side of the speed reducer and is directly connected with the input shaft of the speed reducer, so that the invention accords with the requirement of human-machine ergonomics and the cable can be manually taken up during power failure.