Steering Column Rake Adjustment via Tapered Slot Guides
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Solution Overview
Problem
Existing steering column assemblies face challenges in achieving lash-free adjustment while maintaining structural integrity, particularly in applications requiring axially fixed lower steering shafts, where axial translation is undesirable, often resulting in complex assemblies or tight tolerance components.
Innovation Solution
The rake adjustment mechanism incorporates a lower jacket with tapered slots and rake guides that are translatable within these slots, along with a rake bolt extending through the jacket and bracket, allowing axial adjustment without translating the steering shaft, using a combination of tapered geometry and flexible connections to maintain a stiff, lash-free interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If tight tolerance interface components or complicated assemblies with additional components are used to eliminate axial translation, then axial translation is prevented, but device complexity increases
Solution Approach 1:
The lower jacket is segmented into two separate tapered slots on opposing sides, each containing its own rake guide. This segmentation allows each slot-guide pair to independently constrain axial translation while maintaining overall structural simplicity and avoiding the need for complex additional components.
2Reliability
If joints are held rigidly together to be lash-free, then lash-free performance is achieved, but adjustment capability is inhibited
Solution Approach 1:
The rake guides are designed to be translatable within the tapered slots during adjustment operations, creating a dynamic interface that allows movement when needed. Once adjusted, the tapered geometry provides rigid constraint to eliminate lash, thus achieving both adjustability and lash-free performance through conditional rigidity.
Solution Approach 2:
The tapered slot geometry changes the constraint parameters dynamically - during adjustment, the wider portion of the tapered slot allows greater freedom of movement, while in the final positioned state, the narrower portion provides tight constraint to eliminate lash, thus adapting the joint characteristics to the operational phase.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables precise rake adjustment with high stiffness and natural frequency, preventing axial translation of the steering shaft while ensuring a consistent rake load and improved noise performance, thus enhancing the structural performance and actuation efficiency of the steering column assembly.
Implementation Method 1
a lower jacket defining a first tapered slot and a second tapered slot, the first and second tapered slots disposed on opposing sides of the lower jacket
Implementation Method 2
The rake guide includes a first portion and a second portion flexibly connected to each other with a hinge extending along a length of the rake guide
Data Source
AI summary
A rake adjustment mechanism of a steering column assembly includes a lower jacket defining a first tapered slot and a second tapered slot, the first and second tapered slots disposed on opposing sides of the lower jacket. Also included is a rake bracket coupled to the lower jacket. Further included is a first rake guide and a second rake guide, each rake guide a single, integrally formed component and disposed between the lower jacket and rake bracket, the first rake guide disposed at least partially within the first tapered slot and the second rake guide disposed at least partially within the second tapered slot, each rake guide translatable within the tapered slot in an axial direction of the lower jacket. Yet further included is a rake bolt extending through the lower jacket, the rake bracket and the first and second rake guides.