Granted Patent B2

US 7,377,988 · App. 10/410,938 · Granted May 27, 2008

Abstract

Claims (6)

1. A bearing shaft with a hardened section serving as a raceway for rolling elements in a reception bore of a housing, at least one end of the shaft being adapted to be swaged to the reception bore for achieving at least one of a force locking and a positive engagement, and an outer peripheral hardened surface of the shaft having a hardness that is greater than a hardness of ends of the shaft, wherein the entire shaft is at first carbonitrided, quenched and tempered so that a hardness of HV 745-950 (HRC 62-68) is realized, following which, the thus treated shaft is soft annealed to produce a hardness of HV 212-305 (HRB 93-HRC 30), and the outer peripheral surface is then subjected to induction hardening to achieve a final hardness of HV 745-950 (HRC 62-68).

2. A shaft of claim 1 , wherein, after induction hardening, the outer peripheral surface of the shaft comprises fine, well-dispersed spheroidal carbides in a matrix of tempered martensite, with a retained austenite content of 5-25%.

3. A shaft of claim 1 having a solid configuration.

4. A shaft of claim 1 , wherein at least a region of the ends of the shaft has a hollow cylindrical configuration.

5. A shaft of claim 1 used for mounting a roller in an actuating lever of a valve train of an internal combustion engine.

6. A shaft of claim 1 used for mounting a planetary pinion in an automatic transmission of an automotive vehicle.

Assignments (6)