Abrasive grinding wheel and related production method

Abstract

An abrasive grinding wheel ( 10 ) that comprises an annular body ( 20 ) made of abrasive material provided with a central hole ( 21 ) and a reducing ring ( 30 ) provided with a central attachment hole ( 32 ), wherein the reducing ring ( 30 ) is inserted into the central hole ( 21 ) so that the attachment hole ( 32 ) of the reducing ring ( 30 ) is coaxial with respect to the central hole ( 21 ) of the annular body ( 20 ), wherein the reducing ring ( 30 ) comprises two opposing enlarged axial end stretches ( 311 and 312 ) configured to axially lock the reducing ring ( 30 ) to the central hole ( 21 ) of the annular body ( 20 ).

1 . A method for producing abrasive grinding wheels that comprises:
 forming, through a pressing of an abrasive mixture comprising abrasive powders and a resinoid binder; an annular body provided with a central hole;   inserting a reducing ring provided with a central attachment hole inside said central hole of the annular body, so that the attachment hole is coaxial with respect to the central hole; and   fixing the reducing ring to the annular body by means of riveting the reducing ring.   
     
     
         2 . The method according to  claim 1 , wherein the fixing of the reducing ring by means of riveting comprises plastically deforming at least one edge proximal to an axial end of the reducing ring. 
     
     
         3 . The method according to  claim 1 , wherein the formation of the annular body comprises the creation of the central hole with an axially variable cross section. 
     
     
         4 . The method according to  claim 3  wherein the creation of the central hole provides for the formation of two opposing end stretches having enlarged sections at two axial ends of the central hole and at least one central stretch having a tapered section interposed axially between the two end stretches. 
     
     
         5 . The method according to  claim 4 , wherein the insertion of the reducing ring inside the central hole provides for the coaxial insertion of the reducing ring in the central hole, so that an enlarged axial end stretch of the reducing ring substantially engages to measure with one of the end stretches of the central hole and wherein the fixing of the reducing ring to the annular body through riveting of the reducing ring provides for riveting a further axial end stretch of the reducing ring so as to radially enlarge such further axial end stretch of the reducing ring; the further axial end stretch of the reducing ring thus radially enlarged engaging to measure with the other end stretch of the central hole. 
     
     
         6 . The method according to  claim 1 , wherein the fixing of the reducing ring to the annular body is performed through hot riveting of the reducing ring. 
     
     
         7 . The method according to  claim 1 , which comprises the step of enlargement through milling of the attachment hole of the reducing ring. 
     
     
         8 . An abrasive grinding wheel that comprises:
 an annular body made of abrasive material, obtained by pressing of an abrasive mixture comprising abrasive powders and a resinoid binder, wherein the annular body is provided with a central hole; and   a reducing ring provided with a central attachment hole, wherein the reducing ring is inserted into the central hole so that the attachment hole of the reducing ring is coaxial with respect to the central hole of the annular body, and wherein the reducing ring comprises two opposing enlarged axial end stretches configured to axially lock the reducing ring to the central hole of the annular body.   
     
     
         9 . The abrasive grinding wheel according to  claim 8 , wherein the central hole of the annular body comprises two opposing axial end stretches having enlarged sections with respect to a central stretch having a tapered section axially interposed between the two axial end stretches having enlarged sections, the opposing axial end stretches of the reducing ring substantially engaging to measure with the axial end stretches of the central hole of the annular body. 
     
     
         10 . The abrasive grinding wheel according to  claim 8 , wherein the reducing ring is made of a plastic material.