Method for producing a cam that can be placed on a hollow shaft to form a camshaft

US6438836B1 · kind B1 · utility

Assignee

• Daimlerchrysler AG · US

Inventors

• Andreas Barth · Schnaittach, DE
• Henning Blocker · Seevetal, DE
• Klaus Brandes · Asendorf, DE
• Frank Rohwer · Moisburg, DE

Key dates

• Filing date: May 16, 2001
• Grant date: Aug 27, 2002
• Expiry date: May 16, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T74/2101
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A process is provided for the production of a cam to be joined to a hollow shaft to form a camshaft. In order to make the cam suitable for stable long-term operation on the camshaft, the internal compressive stresses achieved in the cam track before the joining of the cam to the camshaft being so high that the tensile stresses resulting from joining are permanently overcompensated, it is provided that the material selected for the cam is a steel in which the carbon can be dissolved easily as cementite in the pearlite and martensite or is in the form of a fine composite carbide. The cam, which is composed of a hardenable steel, should be fully hardened and, during tempering in the hardening operation, the basic hardness should be set in a range of between 25 and 40 HRC. The cam should then be edge-zone-hardened in a two-stage heating process by induction hardening at a medium frequency of 10-35 kHz, after the preheating stage of the heating process, the introduction of heat being interrupted for 0.3-1.5 seconds. After the action of the preheat, the cam track should then be heated in such a way by means of medium frequency that an edge-zone hardening depth of between at least 0.5 mm …