Torque limiter

The utility model provides a torque limiter. The torque limiter comprises an elastic sheet, an elastic nut, a first main shaft, a second main shaft and a square head which are matched with one another in a manner of penetrating in sequence, wherein the first main shaft comprises a disc part extending in radial direction, and a columnar part and a cylindrical part which axially extend along two sides of the disc part respectively; a plurality of through holes extending axially are uniformly formed along the circumferential direction of the disc part; a plurality of ball sockets corresponding to through holes in the first main shaft are arranged on the second main shaft; a steel ball and a spring are arranged in each through hole; one end of each spring is propped against the bottom surface of the elastic sheet; the other end of each spring is propped against each steel ball and is used for extruding the half of each steel ball into the corresponding ball socket. According to the torque limiter, when the output torque of a pneumatic movable digital display type valve operator is larger than the set torque of the torque limiter, the torque limiter is capable of skidding and idling, thereby playing a role in protecting the valve; the number of the springs and the steel balls can be adjusted according the size of the needed torque safe cut-off value, so that the requirements of different products can be met.