Method of Producing Torque Sensor Shafts

Author:  Renshiro Ishino;Yoshio Shibata
Source:  US Patent 5,205,145
Doc ID:  1992067
Year of Publication:  1992
Abstract:  
This invention relates to a method of producing magnetostriction type torque sensor shafts adapted to detect a change in permeability when a torque is applied. A plurality of shot peening operations are applied to the surface of a torque sensor shaft in such a manner that the diameter of shot particles to be used is decreased each time. This arrangement ensures that the region in which the residual stress is as a maximum and approximately constant lies over a wide range as seen in the direction of the depth from the outermost surface of the shaft and extends from a deep area to an area close to the surface of the shaft. As a result, the hysteresis and nonlinearity of the shaft are improved and it becomes possible to use a wide range of excitation frequencies.