Telescopic Steering Column Locking Cam Mechanism
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Solution Overview
Problem
Existing locking mechanisms for axially adjustable steering columns face challenges in packaging efficiency, load requirements, and dependability, particularly in ensuring proper locked and unlocked conditions while maintaining axial adjustability and collapsible functionality.
Innovation Solution
A locking mechanism comprising a locking cam with a hub, upper arm, and leg defining teeth, which pivots about a pin to engage or disengage with the steering column's teeth, allowing for adjustable locking and unlocking positions through an interface surface and tab mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a telescoping positive lock mechanism is used to maintain fixed telescopic/axial position, then reliability is improved, but device complexity increases
Solution Approach 1:
The locking cam is segmented into distinct functional zones: a locked position zone with first cam surface for engagement, and an unlocked position zone with second cam surface. This segmentation allows the single locking cam to provide reliable locking while maintaining structural simplicity through functional division rather than multiple separate components.
Solution Approach 2:
The locking cam serves multiple functions: it provides positive locking engagement through tooth interaction, enables full telescopic range of motion through the unlocked position, and ensures reliable locking under load through the biased engagement state. This multi-functionality reduces the need for additional specialized components, thereby reducing overall device complexity while maintaining reliability.
2Adaptability or versatility
If a locking mechanism is designed to allow full telescopic range of adjustment, then adaptability is improved, but reliability deteriorates
Solution Approach 1:
The locking cam is designed with dynamic characteristics that allow it to transition smoothly between locked and unlocked states. The cam surfaces are profiled to provide progressive engagement and disengagement, enabling the mechanism to adapt to the full telescopic range while maintaining reliable locking at any positioned. The spring bias dynamically adjusts the engagement force based on operational conditions.
Solution Approach 2:
The cam surface geometry changes parameters throughout the telescopic range: the first cam surface provides high engagement force for reliable locking, while the second cam surface allows disengagement for full adjustment range. This parameter variation in the cam profile enables the mechanism to maintain reliability across the entire telescopic range of motion.
3Area of stationary object
If the upper arm and leg are positioned close together, then packaging efficiency is improved, but ease of operation deteriorates
Solution Approach 1:
The adjustment lever is positioned in a different spatial dimension relative to the locking cam, approaching from a direction that allows access to the cam interface without requiring excessive lateral space. This dimensional arrangement enables compact packaging of the locking mechanism while maintaining ease of operation through lever actuation from an accessible position.
Solution Approach 2:
The adjustment lever acts as an intermediary between the operator and the locking cam, providing mechanical advantage and force multiplication. This intermediary mechanism allows the operator to easily actuate the locking cam with minimal force, making operation easy even when the upper arm and leg are positioned close together for compact packaging.
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
The solution enhances operational dependability and packaging efficiency by ensuring secure locking and flexible adjustment of the steering column, allowing for full telescopic/axial range while maintaining safety during energy absorption events.
Implementation Method 1
a pin extending through the locking cam to allow the locking cam to pivot about the pin between the locked position and the unlocked position
Data Source
AI summary
A locking mechanism for an axially adjustable steering column having an adjustment lever, the locking mechanism includes: a locking cam including a hub, an upper arm, and a leg defining a set of teeth, the upper arm and the leg extend from the hub in a same direction to define a space therebetween, the upper arm includes an interface surface facing the leg that interfaces with the adjustment lever to move the locking cam between a locked position and an unlocked position; and a pin extending through the locking cam to allow the locking cam to pivot about the pin between the locked position and the unlocked position. In the locked position, the set of teeth of the leg engage with a set of teeth of the axially adjustable steering column. In the unlocked position, the set of teeth of the leg are spaced apart from the set of teeth of the axially adjustable steering column.