Steering Column Collapse Limiter Cam Mechanism

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Solution Overview

Problem

Traditional stowable steering columns face challenges in implementing a fixed limiter feature for energy absorption stroke distance, especially when the available stow/telescope stroke is greater than the desired energy absorption stroke, and pyrotechnic devices used for motion limitation are costly and complex to manage.

Innovation Solution

A steering column assembly with a collapse limiting feature that includes a cam portion and a blocking portion, allowing a greater range of travel during stowing while arresting motion after a prescribed energy absorption stroke, using a telescope drive bracket and multiple jackets to enable bi-modal operation for stowing and energy absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed limiter feature is implemented in a stowable steering column, then energy absorption stroke distance is limited, but the available stow/telescope stroke is greater than the desired energy absorption stroke

Engineering Contradiction:

Improveenergy absorption stroke limitationVSAvoidstow/telescope stroke

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The collapse limiting feature transitions from a static blocking position to a retracted position through cam surface interaction. The blocking portion dynamically moves out of the first jacket's path during stow/telescope operations when the cam surface engages, allowing full stroke range, while automatically returning to block the path during energy absorption events when hydraulic pressure drops.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The collapse limiting feature serves dual functions: it limits energy absorption stroke distance during impact events while simultaneously allowing full stow/telescope stroke during normal operations. The same mechanical component adapts its function based on the operational mode, eliminating the need for separate limiting mechanisms for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If pyrotechnic pin-extension devices are used for motion limitation, then energy absorption stroke is limited, but device complexity and cost increase

Engineering Contradiction:

Improveenergy absorption stroke limitationVSAvoidpyrotechnic device complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex pyrotechnic mechanical systems with a hydraulic-mechanical system. The collapse limiting feature is actuated by hydraulic pressure differential rather than pyrotechnic ignition, eliminating the need for specialized pyrotechnic components, monitoring systems, and special warehousing requirements while achieving the same motion limitation function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The collapse limiting feature automatically actuates based on hydraulic pressure conditions without requiring external pyrotechnic ignition or electronic monitoring. The hydraulic system itself provides the actuation force through pressure differential, making the system self-regulating and eliminating the need for specialized pyrotechnic device management.

Inventive Principle:

Principle #25Self-service

3Reliability

If a blocking portion is positioned to limit energy absorption stroke, then energy absorption is controlled, but it impedes normal stow/telescope actuation

Engineering Contradiction:

Improveenergy absorption stroke controlVSAvoidstow/telescope actuation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The blocking portion dynamically changes position based on operational mode. During normal stow/telescope operations, hydraulic pressure on the cam surface pushes the blocking portion out of the first jacket's path, allowing full range of motion. During energy absorption events, pressure differential causes the blocking portion to return to its blocking position, automatically controlling stroke without impeding normal operations.

Inventive Principle:

Principle #15Dynamics

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 allows for unimpeded stow/telescope actuation under normal conditions while providing motion arrest during energy absorption, effectively managing the stroke distance and eliminating the need for costly pyrotechnic devices.

Implementation Method 1

contact between the telescope drive bracket and the cam portion biases the blocking portion out of a first jacket path

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Gradient

Implementation Method 2

limitation of the overall energy absorption axial displacement distance

Methodology Applied

Scientific EffectEnergy absorption: Deformation

Data Source

PatentUS11958526B2Steering column energy absorption displacement limiter

Publication Date: 2024.04.16 STEERING SOLUTIONS IP HOLDING CORP

AI summary

A steering column assembly includes a telescope drive bracket. The steering column assembly also includes a first jacket operatively coupled to the telescope drive bracket. The steering column assembly further includes a second jacket, wherein the first jacket is telescopingly moveable relative to the second jacket. The steering column yet further includes a collapse limiting feature having a cam portion and a blocking portion, wherein the blocking portion defines a first range of travel of the first jacket in a first position, wherein contact between the telescope drive bracket and the cam portion biases the blocking portion out of a first jacket path to allow a second, greater range of travel for the first jacket.