The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 13, 2001
Filed:
Dec. 31, 1999
James S. Fisher, Auburn, IN (US);
Roland C. Smith, Milford, IN (US);
Dana Corporation, Toledo, OH (US);
Abstract
Bevel gears having a carbon content of at least about 0.4% by weight, preferably 0.5% by weight are manufactured by a process which includes forging a steel blank having a carbon content of at least 0.4% by weight until a bevel gear precursor having essentially the tooth configuration and dimensions of the desired product gear is obtained, and hardening the teeth of the gear precursor by induction heating without machining of the teeth. The initial forging is precise enough so that no further machining of the teeth is required. This requires forging to a tolerance specified in AGMA class 6. The gear is then induction hardened, first by preheating at a lower frequency, say 10 KHz, then induction heating at a higher frequency, say 50 KHz, in order to obtain a desired hardness profile. The desired hardness profile includes the surface hardness of at least 50, preferably 60, on the Rockwell C scale and a core hardness not over Rockwell C 45, preferably from Rockwell 25 to Rockwell 40. This invention provides a low-cost manufacturing process which is especially suited for differential gears, such as pinion mate gears and side gears, and other non-automotive gears that do not have to carry a high torque load. This process eliminates costly steps of manufacturing and carburizing heat treatment.