Steering Length Adjuster with Unthreaded Load Path

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Solution Overview

Problem

Existing steering mechanisms for vehicles are prone to reduced durability due to the transfer of bending and buckling loads through threaded sections, which can lead to mechanical failure over time.

Innovation Solution

A steering mechanism design featuring a center link and tie rods with female threads spaced by unthreaded portions, interconnected by a length adjuster with male threads and an unthreaded middle section, allowing for adjustable length and clamping around overlapping unthreaded areas to distribute loads differently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If threaded sections are used to interconnect center link and tie rod, then adjustment and assembly are simplified, but bending and buckling loads cause reduced durability and mechanical failure

Engineering Contradiction:
Improveassembly simplicityVSAvoiddurability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The length adjuster is divided into three distinct sections: a first threaded section for engaging the center link, an unthreaded middle section for load transfer, and a second threaded section for engaging the tie rod. This segmentation allows threaded portions to handle assembly/adjustment functions while the unthreaded middle section handles structural load transfer, resolving the contradiction between ease of assembly and durability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the length adjuster have different structural properties: threaded sections provide adjustable connectivity while the unthreaded middle section provides superior load-bearing capacity. By applying different structural qualities to different locations, the design achieves both ease of assembly and high reliability under bending and buckling loads.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If clamping mechanism is tightened to secure threaded union, then connection stability is improved, but stress concentration on threads increases

Engineering Contradiction:
Improveconnection stabilityVSAvoidthread stress
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The load-carrying function is extracted from the threaded sections and transferred to the unthreaded middle section. The threaded sections are removed from the load path, leaving only the function of connection and adjustment. This extraction eliminates stress concentration on threads while maintaining connection stability through the clamping mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The unthreaded middle section acts as an intermediary element between the center link and tie rod, mediating the load transfer. By introducing this intermediate unthreaded section, the design allows threaded connections to provide stability while preventing direct stress transmission to the threads.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3094541B1Length adjuster and clamping mechanism for a steering mechanism
Publication Date: 2019.01.16 FEDERAL MOGUL MOTORPARTS LLC
  • EP3094541B1 patent drawingFigure 1~2
  • EP3094541B1 patent drawingFigure 3~4B
  • EP3094541B1 patent drawingFigure 5A~6B

AI summary

The steering mechanism includes a center link which extends between opposite longitudinal ends. Each end has a bore with threads which are spaced from the end by an unthreaded portion. A tie rod includes a bore with threads that are spaced form an end of the tie rod by an unthreaded portion. A length adjuster threadedly connects one of the longitudinal ends of the center link with the tie rod. The length adjuster includes threaded sections and an unthreaded middle section. The unthreaded middle section overlaps with the unthreaded portions of the center link and tie rod bores respectively. A first clamp is clamped around the overlapping unthreaded portion of the center Sink bore and the unthreaded middle section of the length adjuster, and a second clamp is clamped around the overlapping unthreaded portion of the tie rod bore and the unthreaded middle section of the length adjuster.