Stamped Steel Outer Cam Press-Fit for Steering Column Clamp Force
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Solution Overview
Problem
Steering systems using stamped steel components face challenges in maintaining clamp forces and increasing costs due to the need for additional parts to retain the stamped steel follower, which was intended to replace more expensive powdered metal parts.
Innovation Solution
A cam assembly featuring a stamped steel outer cam with a press fit within a pocket defined by the lever, eliminating the need for additional fasteners and incorporating a rake adjustment assembly with a rotatable rake lever and bolt for clamping, utilizing a plurality of legs for interaction with an inner cam to lock and unlock the steering column position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stamped steel components are used to replace powdered metal parts, then manufacturing cost is reduced, but additional parts and fasteners are required which increases device complexity and may compromise clamp force reliability
Solution Approach 1:
The outer cam is press-fit directly into the lever assembly, merging two previously separate components (outer cam and lever) into a single integrated unit. This eliminates the need for additional fasteners and retention parts, reducing device complexity while maintaining the cost advantages of stamped steel construction.
Solution Approach 2:
The outer cam is nested within a pocket defined by the lever assembly, with the outer cam fitting inside the lever's structural envelope. This nested configuration allows the outer cam to be retained securely without requiring external fasteners, as the lever assembly itself provides the retention structure.
2Reliability
If additional parts are added to retain stamped steel follower, then reliability of clamp force is improved, but device complexity and cost increase
Solution Approach 1:
The retention function is merged into the lever assembly structure itself through the pocket feature. The pocket provides both structural support and retention for the outer cam, eliminating the need for separate retention parts while maintaining reliable clamp force through the integrated design.
Solution Approach 2:
The lever assembly serves dual functions: it provides structural support and simultaneously retains the outer cam through the integrated pocket feature. The design is self-sufficient, requiring no external retention mechanisms, which maintains reliability while reducing part count.
3Device complexity
If press fit method is used to integrate outer cam with lever, then additional fasteners are eliminated, but manufacturing precision requirements increase
Solution Approach 1:
The pocket in the lever assembly and the outer cam are designed with specific dimensional parameters that enable press-fit engagement. By carefully controlling the size and geometry of the pocket and outer cam interface, the design achieves reliable retention through press-fit without requiring additional fasteners, balancing manufacturing precision requirements with fastener elimination.
Data Source
AI summary
A rake adjustment assembly for a steering column system includes a rake lever that is rotatable. The rake adjustment assembly also includes a rake bolt operative coupled to the rake lever and positioned to selectively exert a clamping force to lock and unlock the rake position of the steering column system. The rake adjustment assembly further includes a cam assembly comprising an outer cam formed of stamped steel and press fit within a pocket defined by an outer face of the lever. The outer cam includes a main body. The outer cam also includes a plurality of legs extending from the main body.