External speed measuring device for roller motor

The utility model relates to an external speed measuring device for a roller motor, which comprises a supporting bottom plate, a motor body and a tachometer body, the motor body is arranged at the top end of the supporting bottom plate, and the tachometer body is arranged on one side of the top end of the supporting bottom plate. A sliding assembly is arranged at the position, between the motor and the tachometer body, of the top end of the supporting bottom plate, the sliding assembly comprises a sliding block, a detection assembly is installed at the top end of the sliding block, and the detection assembly comprises a detection block; one end of an output shaft of the motor body is provided with a rotating assembly which is used for cooperating with the detection assembly to carry out rotating speed detection. According to the utility model, the distance between the detection block and the output shaft of the motor body can be kept unchanged through the arrangement of the sliding strip and the sliding groov