Steering Column Rake Pivot Assembly Alignment Bushing
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Solution Overview
Problem
The existing two-bracket mounting system for steering column assemblies can lead to misassembly and reduced travel in the sliding joint due to potential axial mispositioning and relative bias between the lower brackets, resulting in insufficient or shortened travel, especially when the lower brackets are not correctly aligned and pivoted during assembly.
Innovation Solution
A rake pivot assembly featuring a pair of flanges with elongated openings, lower brackets fitting over the flanges, alignment bushings within these openings, and lower bracket pins extending through the flanges to couple the brackets, ensuring proper alignment and preventing off-center assembly errors through the use of alignment bushings with elliptical segments and a flexible strap, which constrain the lower bracket pin during assembly but allow smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-piece lower bracket system is used to reduce weight and cost, then manufacturing cost and weight are reduced, but assembly alignment precision and reliability deteriorate due to potential axial mispositioning and relative bias between brackets
Solution Approach 1:
The alignment bushing acts as an intermediary component between the lower bracket and flange. It features an elongated opening that guides the lower bracket pin during assembly, ensuring proper axial positioning and preventing misalignment. The bushing with its specific geometry (elongated opening oriented perpendicular to the pivot axis) serves as a mechanical guide that constrains the pin to the correct path, thereby maintaining assembly precision while allowing the use of cost-effective two-piece brackets
Solution Approach 2:
The alignment bushing and elongated opening configuration enable self-aligning assembly. The elongated opening automatically guides the lower bracket pin into the correct position during assembly without requiring external alignment tools or procedures. The design inherently prevents misassembly through its geometric constraints, making the assembly process self-correcting and eliminating the need for complex alignment procedures
2Manufacturing precision
If alignment bushings with elongated openings are added to ensure proper alignment, then assembly alignment precision is improved, but device complexity increases
Solution Approach 1:
The alignment bushing serves multiple functions simultaneously: it acts as a structural connector between the lower bracket and flange, provides alignment guidance through its elongated opening, constrains the lower bracket pin to the correct path, and prevents misassembly. By consolidating these multiple functions into a single component, the design achieves high alignment precision without proportionally increasing complexity, as the bushing is a simple cylindrical part with an elongated opening
3Weight of moving object
If two-piece lower brackets are used to make structures lighter and more cost effective, then weight and cost are reduced, but reliability deteriorates due to potential misassembly and insufficient travel
Solution Approach 1:
The alignment bushing with its elongated opening pre-constrains the lower bracket pin to the correct assembly path before final assembly is complete. This preliminary constraint prevents misassembly from occurring in the first place by guiding the pin into proper alignment during the assembly process. The design proactively prevents the harmful effect of misassembly rather than relying on post-assembly adjustments or inspections
Solution Approach 2:
The alignment bushing serves as a mediator that ensures reliable operation of the two-piece lower bracket system. By providing a precise geometric interface between the brackets and flanges, it eliminates relative bias and ensures consistent travel distance. The bushing mediates the interaction between the two separate brackets, making them function as a unified, reliable assembly despite being manufactured as separate pieces
Data Source
AI summary
A rake pivot assembly for a steering column assembly includes a pair of flanges spaced from each other and oriented parallel to each other, each of the flanges defining an elongated opening. The assembly also includes a pair of lower brackets, each of the lower brackets having a portion thereof fitting over one of the pair of flanges. The assembly further includes a pair of alignment bushings, each of the pair of alignment bushings at least partially disposed within one of the elongated openings and positioned between one of the lower brackets and one of the flanges. The assembly yet further includes a pair of lower bracket pins, each of the lower bracket pins extending along a pivot axis of the steering column assembly and through one of the lower brackets and through one of the flanges to couple one of the lower brackets to one of the flanges.