Appeal No. 1998-0123
Application No. 08/251,575
comprising 0.1 wt% up to 1.2 wt% of carbon and the balance
being Fe, the one of the components having a hardened layer
with a grinding allowance portion after being subjected to
carbonitriding and hardening heat treatments, followed by
grinding the grinding allowance portion to obtain a finished
component part having a surface layer which removes the
grinding allowance portion from the hardened layer,
wherein said surface layer comprises:
carbon in a range from 0.9 wt% up to 1.6 wt%;
nitrogen in a range from 0.05 wt% up to 0.3 wt%;
said nitrogen content being at least 0.05 wt% at a depth
of 2% of a diameter of the finished component part inwardly
from a surface of the surface layer; and
a nitrogen gradient, which is the rate of change in the
concentration of nitrogen in the depth direction of said
surface layer, not exceeding 0.5 wt%/mm.
The examiner relies upon the following references as
evidence of obviousness:
Furumura et al. 4,871,268 Oct. 3, 1989
(Furumura)
Hoshino (JP '257) 3-24257 Feb. 1, 1991
(Japanese Published Unexamined Patent Application)
Appellants' claimed invention is directed to a rolling
bearing that has been subjected to carbonitriding and
hardening, followed by grinding to provide a surface layer
comprising carbon and nitrogen in the recited amounts and
possessing a nitrogen gradient not exceeding 0.5 wt%/mm. The
-2-
Page: Previous 1 2 3 4 5 6 7 8 Next
Last modified: November 3, 2007