Shaft part formed with a rolling groove
AssigneeNtn Corporation
InventorsHiroyuki Uchida, Kenji Ouwa, Kazuho Mimura, Kazuhiko Yoshida
Life of this patent
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Abstract
A shaft part is formed with a rolling groove (5) on which rolling elements (4) roll. At least the rolling groove (5) is induction hardened with no generation of black colored oxidized scale after the induction hardening. A surface of the induction hardened rolling groove (5) is used “as is” as a rolling surface. The surface roughness Ra of the induction hardened surface “as is” of the rolling groove (5) is less than 1.0. The ratio of effective hardened depth of a hardened layer is between 0.15 and 0.45.
Claims13
A shaft part, formed with a rolling groove on which rolling elements roll, comprising:
- at least the rolling groove is induction hardened and has no generation of black colored oxidized scale after the induction hardening, a surface of the induction hardened rolling groove is used, as a rolling surface immediately after the induction hardening process;
- the shaft part is carbon steel including carbon content of 0.47-0.6 wt % and Si of 0.02-0.1 wt %, Cr of from 0.02 to <0.05 wt %, B of 0.0003-0.006 wt %;
- surface roughness Ra of the induction hardened surface, of the rolling groove, immediately after the induction hardening process, is less than 1.0, and a ratio of effective hardened depth of a hardened layer is about 0.15 to about 0.45.
Dependencies are inferred from the claim text.