JPS5797421A - Method and device for measuring torque - Google Patents

Abstract

PURPOSE:To measure torque with high precision by fitting one of two cylindrical magnets, whose overall circumferences are polarized at equal intervals, in the other freely and rotatably at a prescribed interval, and detecting an angle of torsion between both the cylindrical magnets in rotation. CONSTITUTION:A driving shaft 6 is coupled with a prime mover, and a load is coupled with a driven shaft 7. When the prime mover is driven, the driving shaft 6, a detection gear 2, a holding tube 15, and an external-ring magnet 13 rotate in one body. The external-ring magent 13 and an internal-ring magnet 14 are polarized at equal intervals to have equal numbers of poles, so that counter magnets have the opposite polarities, so that attractive force operates between poles N and S. The internalring magnet 14 rotates synchronizing with the external- ring magnet 13, and the detection gear 3 and driven shaft 7 rotate together with it. Once a load is applied on the driven shaft 7, the opposte magnets 13 and 14, i.e. detection gears 2 and 3 are displaced from each other at a prescribed angle to generate a phase difference between output signals of gear sensors 4 and 5, thereby calculating the load. Thus, torque is measured with high precision.