Gear rim and gears produced therefrom

Abstract

Disclosed herein is a multi-segmented fabricated gear rim and gear formed therefrom. Each gear rim segment in the gear is formed from a single unsegmented steel plate. The steel plate has an upper surface from which gear teeth are cut and a lower surface on which the gear sub-structure is welded. Relative to each other, the upper surface of the steel plate possesses high hardenability and poor weldability and the lower surface possesses low hardenability and good weldability. The steel plate is preferably formed using a decarburization process.

What is claimed is:  
     
         1 . A welded assembly comprising a single distinctive steel plate having an upper surface and a lower surface, the upper surface having a higher hardness and carbon content than the lower surface, said upper surface not being suitable for welding; and said lower surface having a ferrous material welded thereto.  
     
     
         2 . A multi-segmented fabricated gear rim, with each gear rim segment being formed from an single unsegmented steel plate, said steel plate having an upper surface from which gear teeth are cut and a lower surface, wherein, relative to each other, the upper surface possesses high hardenability and poor weldability and the lower surface possesses low hardenability and good weldability.  
     
     
         3 . A multi-segmented fabricated gear which is formed from a plurality of gear rim segments, with each gear rim segment being formed from an single unsegmented steel plate, said steel plate having an upper surface from which gear teeth are cut and a lower surface, wherein, relative to each other, the upper surface possesses high hardenability and poor weldability and the lower surface possesses low hardenability and good weldability, wherein there is a gear substructure welded to the lower surface of each steel plate.  
     
     
         4 . A process for forming a multi-segmented fabricated gear comprising (a) subjecting a single flat, unsegmented, steel plate having an inner layer and an outer layer to a decarburization process to thereby reduce the carbon content on all surfaces of the plate exposed to the decarburization process; (b) bending the plate to form a arc-like segment of a circular gear rim; (c) welding gear sub-structure to the decarburized inner layer of the plate; (d) attaching the ends of the welded plate to the ends of one or more similarly decarburized and welded plates to form a circular unit; (e) machining the decarburized surface from the outer layer of the plate; and (f) cutting the gear teeth from the machined outer layer of the plate.