TORQUE LIMITER AND VALVE ACTUATOR

摘要

A torque limiter which can detect torque of both opening and closing of a valve and in which different torque values for opening and closing of the valve can be easily set. The torque limiter (17) is provided with a torque arm (171) having a connection section (171b) which is connected to a drive side gear (24) and an intermediate gear (23) and also having an arm section (171a) projecting from the connection section (171b); an opening spring means (172) and a closing spring means (173) which apply spring force balancing with force acting, in proportion to torque of a load in opening and closing operation of the valve, in the direction of a tangential line at the meshing point of the intermediate gear (23); an opening torque detecting switch (175) and a closing torque detecting switch (174) which are, when torque of a load in opening and closing operation of the valve exceeds a predetermined value, operated by the arm section (171a); and a torque limiter shaft (176) passed through the opening and closing spring means (172, 173). The torque limiter shaft (176) is adapted such that spring force of each of the opening and closing spring means (172, 173) can be adjusted from an end of the torque limiter shaft (176).