Single-Actuator Steering Column Lift and Clamp Lock
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Solution Overview
Problem
Existing locking mechanisms in axially adjustable steering columns lack dependability and efficient load management during collapse events, particularly in vehicle steering systems.
Innovation Solution
A dual-direction locking mechanism with interlocking cams and an energy-absorbing strap, allowing selective locking and unlocking of the steering column assembly, featuring separate tooth tracks for axial direction control and energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a telescoping positive lock mechanism is used to maintain fixed axial position, then locking reliability is improved, but the mechanism increases device complexity and packaging space requirements
Solution Approach 1:
The locking mechanism is segmented into two separate cams (first cam and second cam), each responsible for locking in one axial direction. This segmentation allows each cam to be simpler in design while collectively providing bidirectional locking reliability, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The locking mechanism transitions from a single-dimensional locking approach to a two-dimensional approach by using two cams arranged at different angular positions (e.g., 180 degrees apart). This dimensional change enables bidirectional locking without significantly increasing overall mechanism complexity.
2Reliability
If a telescoping positive lock mechanism is used to maintain fixed axial position, then locking reliability is improved, but packaging space requirements increase
Solution Approach 1:
The first and second cams are nested within the same rotational assembly, sharing a common rotational axis and housing space. This nesting allows the bidirectional locking mechanism to occupy approximately the same volumetric space as a single cam, maintaining compact packaging while achieving improved reliability.
3Manufacturing precision
If separate tooth tracks are used for axial direction control, then locking precision in both directions is improved, but the energy absorption capability during collapse events is reduced
Solution Approach 1:
The energy absorbing strap acts as an intermediary element between the two cam mechanisms. It provides a controlled deformation path that absorbs collapse energy while the cam teeth maintain precise locking engagement, thus preserving both locking precision and energy absorption capability.
Solution Approach 2:
The energy absorption function is extracted from the primary locking function by introducing a dedicated energy-absorbing strap component. This separation allows the tooth tracks to focus on precision locking while the strap independently handles energy absorption during collapse events.
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
Enhances the dependability and operational reliability of the steering column by ensuring secure locking and controlled axial adjustment, while providing energy absorption during collapse events.
Implementation Method 1
The locking mechanism includes a first cam having a plurality of teeth engageable with the first series of teeth in the locked position and disengaged from the first series of teeth in the unlocked position. The locking mechanism further includes a second cam having a plurality of teeth engageable with the second series of teeth in the locked position and disengaged from the second series of teeth in the unlocked position.
Implementation Method 2
The locking mechanism includes an energy absorbing strap defining a first series of teeth extending axially and a second series of teeth extending axially.
Data Source
AI summary
An axially adjustable steering column includes a first jacket. The steering column also includes a second jacket, wherein the first jacket is axially adjustable relative to the second jacket. The steering column further includes an adjustment lever. The steering column yet further includes a locking mechanism, wherein the adjustment lever selectively moves the locking mechanism between a locked position and an unlocked position, wherein the locked position prevents axial adjustment of the first jacket relative to the second jacket in both axial directions, and the unlocked position allows adjustment of the first jacket relative to the second jacket.