Prestressed Brake Drum or Rotor

Author:  Larry B. Hester, Dayton, OH
Source:  US Patent 5,352,305
Doc ID:  1994041
Year of Publication:  1994
Abstract:  
Uniformly distributed compressive stresses are induced in the machined surfaces of brake drums and brake rotors. The compressive stresses cancel residual tensile stresses induced in the surfaces by machining operations during fabrication. Cancellation of the surface tensile stresses delays formation of cracks during brake service use and extends the service life of the brake drum or rotor. Shot peening is an applicable prestressing process which also imparts a surface roughness that reduces the time required to burnish brake pads to match the shape of the drum or rotor surface. The reduction of burnishing time reduces the amount of surface cracking caused by surface heating by brake pad high spots as the high spots are ground down.