Progressively stamped clip-on noise damping shim for friction assembly, and method and apparatus for producing clip-on noise damping shim

Abstract

A noise damping shim for a friction assembly is produced by a pre-slit step and a bend and blank step. The pre-slit step forms pre-slits in a shim material at locations where tabs of a noise damping shim are to be formed. The bend and blank step bends each of the tabs at a bent angle relative to the shim material while simultaneously blanking a shim body from the shim material to produce a noise damping shim having bent tabs extending outwardly from a periphery of the shim body.

1 . A noise damping shim for a friction assembly, the shim comprising:
 a shim body that provides a noise damping function when the friction assembly is in use, the shim body having opposing surfaces and a periphery between the opposing surfaces; and   one or more tabs extending outwardly from the periphery of the shim body, each tab having a base section integrally connecting the tab with the shim body, a hook section for engaging with the friction assembly backing plate, and a bent section integrally connecting the base section and the hook section at a bent angle,   wherein an intersection between the periphery of the shim body and each side edge of the base section of each tab forms a sharp corner.   
     
     
         2 . The noise damping shim as claimed in  claim 1 , wherein an angle of the sharp corner between the periphery of the shim body and each of the side edges of the base section of each tab is between about 60° to 120°. 
     
     
         3 . The noise damping shim as claimed in  claim 2 , wherein the angle of the sharp corner between the periphery of the shim body and each of the side edges of the base section of each tab is about 90°. 
     
     
         4 . The noise damping shim as claimed in  claim 1 , wherein the base section of each tab has opposing side edges, and the base section merges into the shim body such that each side edge of the base section intersects the periphery of the shim body with a slit therebetween. 
     
     
         5 . The noise damping shim as claimed in  claim 4 , wherein the slit extends into the shim body along the side edge of the base section, a length of the slit extending into the shim body is equal to or shorter than about 3 mm. 
     
     
         6 . The noise damping shim as claimed in  claim 1 , wherein the base section of each tab has opposing side edges, and the base section merges into the shim body such that each side edge of the base section intersects the periphery of the shim body without a slit therebetween. 
     
     
         7 . The noise damping shim as claimed in  claim 1 , wherein the bent angle between the base section and the hook section is smaller than 90° so that the nose damping shim is clipped on the friction assembly. 
     
     
         8 . The noise damping shim as claimed in  claim 7 , wherein the bent angle is between about 65° to 85°. 
     
     
         9 - 20 . (canceled) 
     
     
         21 . A progressive stamping apparatus for producing a noise damping shim for a friction assembly, the apparatus comprising a progressive stamping die that includes an upper die and a lower die that open and close for stamping, the stamping die defining:
 a pre-slit stage for forming pre-slits in a shim material at locations where tabs of a noise damping shim are to be formed; and   a bend and blank stage for bending each of the tabs at a predetermined angle relative to the shim material while simultaneously blanking a shim body from the shim material to produce a noise damping shim having bent tabs extending outwardly from a periphery of the shim body.   
     
     
         22 . The progressive stamping apparatus as claimed in  claim 21 , wherein the pre-slit stage comprises one or more slitting mechanisms, each slitting mechanism is provided at a location that corresponds to a tab to be formed, and each slitting mechanism has an slitting member provided in one of the upper die and the lower die for forming a pre-slit when the stamping die closes. 
     
     
         23 . The progressive stamping apparatus as claimed in  claim 22 , wherein the slitting member has a cutting edge corresponding to a peripheral edge of a tab. 
     
     
         24 . The progressive stamping apparatus as claimed in  claim 23 , wherein the cutting edge further corresponds to pre-slit sections extending into the tab body. 
     
     
         25 . The progressive stamping apparatus as claimed in  claim 21 , wherein the bend and blank stage comprises:
 one or more bending mechanisms, each bending mechanism being provided at a location that corresponds to a pre-slit formed by the pre-slit stage; and   a blanking mechanism having a punch and a counter punch for blanking the shim body as the stamping die closes.   
     
     
         26 . The progressive stamping apparatus as claimed in  claim 25 , wherein the bend mechanism has a bending cam that is actuated to bend a tab as the stamping die closes.