Torque-measuring shaft

Abstract

A torque-measuring shaft includes a measuring shaft disposed on a shaft axis of the torque-measuring shaft, loadable in torsion and having at least one rotationally symmetric surface region disposed coaxially with the shaft axis as well as a measuring device disposed on the measuring shaft for measuring a torsion of the measuring shaft, wherein the torque-measuring shaft has a material weakening disposed in radial direction inside the measuring shaft, eccentrically relative to the shaft axis.

What is claimed is: 
     
         1 . A torque-measuring shaft comprising:
 (a) a shaft axis;   (b) a measuring shaft disposed on the shaft axis, loadable in torsion and having at least one rotationally symmetric surface region disposed coaxially with the shaft axis;   (c) a measuring device disposed on the measuring shaft for measuring a torsion of the measuring shaft; and   (d) a material weakening disposed in a radial direction inside the measuring shaft eccentrically relative to the shaft axis;   wherein the material weakening comprises, in the measuring shaft, at least one recess disposed in the radial direction inside the measuring shaft eccentrically relative to the shaft axis; and   wherein said recess perforates the measuring shaft, preferably parallel to the shaft axis.   
     
     
         2 . Torque-measuring shaft according to  claim 1 , wherein a stiffening element, which comes into contact with the rims of the recess, preferably under torsion, is disposed in the recess. 
     
     
         3 . Torque-measuring shaft according to  claim 2 , wherein the stiffening element is formed in one piece with the measuring shaft. 
     
     
         4 . Torque-measuring shaft according to  claim 1 , wherein the recess perforates the measuring shaft parallel to the shaft axis. 
     
     
         5 . Torque-measuring shaft according to  claim 1 , wherein the recess provided with a cover on at least one end, preferably on both ends ( 20 ,  21 ) of the measuring shaft. 
     
     
         6 . Torque-measuring shaft according to  claim 1 , wherein the material weakening is convex in a direction of the rotationally symmetric surface region. 
     
     
         7 . Torque-measuring shaft according to  claim 1 , wherein a measuring web which has a minimum width perpendicular to its axial alignment parallel to the shaft axis and starting therefrom broadens steadily up to a radial extent of the recess, is disposed between the material weakening and the rotationally symmetric surface region. 
     
     
         8 . Torque-measuring shaft according to  claim 7 , wherein the measuring web is formed in one piece with the measuring shaft. 
     
     
         9 . Torque-measuring shaft according to  claim 1 , comprising at least two, preferably at least four material weakenings disposed in radial direction inside the measuring shaft, respectively eccentrically relative to the shaft axis and mutually symmetrically relative to the shaft axis. 
     
     
         10 . Torque-measuring shaft according to  claim 1 , wherein the material weakenings are respectively identically configured. 
     
     
         11 . Torque-measuring shaft according to  claim 1 , wherein the measuring shaft is formed in one piece. 
     
     
         12 . Torque-measuring shaft according to  claim 1 , wherein the measuring means comprise strain gauges and/or are mounted on the rotationally symmetric surface region, preferably in the region of the material weakenings or of a measuring web. 
     
     
         13 . Torque-measuring shaft according to  claim 1 , wherein a flange is attached to or is formed in one piece with the measuring shaft on at least one end, preferably on both ends thereof.