Patents Assigned to Ernst Grob AG
  • Patent number: 4796345
    Abstract: The method of fabricating a rim gear, such as a starter rim gear made of sheet metal, such as sheet steel, comprises cold forming an outer surface of a substantially cylindrical rim portion of a dished blank according to the well known Grob method to effect an external or exterior gear tooth system with proper gear or gear wheel characteristics thereon, thereby also effecting an internal or inner tooth system on the inner surface of the substantially cylindrical rim portion. This method is performed such that at the fabricated rim gear the quotient of the different between an addendum circle diameter or outer diameter of the external gear tooth system and a crown circle diameter or inner diameter of the internal tooth system divided by the wall thickness of the substantially cylindrical rim portion before the start of cold forming is at least 1.6 and that the quotient of the thinnest portion of the tooth flank wall of the fabricated rim gear divided by that wall thickness is at most 0.4.
    Type: Grant
    Filed: July 20, 1987
    Date of Patent: January 10, 1989
    Assignee: Ernst Grob AG
    Inventor: Hans Krapfenbauer