| 摘要 |
PURPOSE:To perform accurate torque measurement free from error due to the gradient of temperature by providing plural coils in the vicinity of a shaft having the magnetostriction effect to compensate an influence due to temperature distribution. CONSTITUTION:Detecting coils L1-L4 form a magnetic circuit [figure (b)] where magnetic fluxes generated from them pass a shaft 1 to be measured. In this case, coils L2 and L4 are formed on peripheral surfaces of magnetic anisotropic parts 4 and 5 where magnetic anisotropies inclined in left-handed and right-handed screw directions to the axis of the shaft 1 are spirally formed, and the permeability in magnetic anisotropic parts 4 and 5 is changed more than that in the other parts when torque is applied. Thus, magnetic fluxes generated from respective coils act upon the shaft at the time of flowing a current to respective coils from an exciting power source 10 and output voltages corresponding to permeability in positions where coils are provided are generated, and torque is operated in accordance with a prescribed formula by an operating means 11, and the error due to temperature distribution is eliminated because coils L1 and L3 out of respective coils are provided in positions where the magnetic anisotropy does not exist. |
