Bishop Innovation Limited

Juergen Dohmann

Lyle John McLean

Johann Friederich Jaeggi

A die apparatus and method for performing a flashless forging operation to manufacture the toothed portion of a steering rack. The die apparatus includes first and second die members and at least one punch member, each having a forming surface shaped substantially as an obverse of a portion of the toothed portion. At least a portion of the forming surface of the first die member is shaped substantially as the obverse of the teeth of the rack. The first and second die members are moveable towards each other to a closed position, thereby partially forging the toothed portion from a blank placed in the die apparatus, and forming a substantially closed cavity defined by the forming surfaces. The punch member is adapted to move into the cavity once the die members are in the closed position, thereby completing the forging operation.

Steering rack manufacture

A method of manufacturing a steering rack for a vehicle rack and pinion steering system. The rack comprises gear teeth and a shank that has a constant outside diameter and constant wall thickness over the majority of its length. The method comprises performing a forging operation on a tubular member with an elongate member positioned in the bore of a thickened region of the tubular member. The forging operation forms the gear teeth on the thickened region, and the elongate member is retained within the tubular member. The tubular member is made by performing a forming operation on a length of tube stock such that the outside diameter of the thickened region is smaller than the outside diameter of the shank, and the wall thickness of the thickened region is larger than the wall thickness of the shank.

Method of manufacturing a steering rack

A die apparatus and method for performing a flashless forging operation to manufacture the toothed portion of a steering rack. The die apparatus includes first and second die members and at least one punch member, each having a forming surface shaped substantially as the obverse of a portion of the toothed portion. At least a portion of the forming surface of the first die member is shaped substantially as the obverse of the teeth of the rack. The first and second die members are moveable towards each other to a closed position, thereby partially forging the toothed portion from a blank placed in the die apparatus, and forming a substantially closed cavity defined by the forming surfaces. The punch member is adapted to move into the cavity once the die members are in the closed position, thereby completing the forging operation.

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Redfern, Australia

Juergen Dohmann