Runflat Insert Locking Mechanism for Surface Pressure Management

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Solution Overview

Problem

Existing emergency running inserts for motor vehicle wheels face issues with surface pressure increases and potential damage when screws are tightened, leading to impairments in the connection of partial elements.

Innovation Solution

The use of cast material partial elements with internal threads and metallic plates, along with elastic material buffers and reduced thickness plates, allows for improved force distribution and assembly without requiring screw nuts, enabling better performance characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If screws are tightened by nuts to connect partial elements, then the connection strength is improved, but surface pressure increases leading to damage

Engineering Contradiction:
Improveconnection strengthVSAvoidsurface pressure
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

A casting intermediary material is introduced between the screw/nut connection and the partial element surfaces. The screw passes through a through-bore in the casting, and the casting material surrounds and distributes the clamping force, preventing concentrated surface pressure while maintaining connection strength

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connection method is changed from direct metal-to-metal contact with nuts to a casting-embedded screw connection. The casting material transforms the concentrated clamping force into distributed stress, changing the pressure parameters from high local concentration to lower distributed pressure

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If nuts are used to secure screws, then the connection is stabilized, but assembly complexity increases due to positioning and anti-twisting requirements

Engineering Contradiction:
Improveconnection stabilityVSAvoidassembly complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The nut component is completely removed from the connection system. Instead of using nuts that require positioning and anti-twisting measures, the screw threads directly engage with threaded holes in the casting, eliminating the need for separate nut installation and securing operations

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fastening function previously requiring separate screw and nut components is merged into a single screw-component system where the screw threads directly engage with the casting. This combines multiple functions (connection, stabilization, positioning) into one simplified assembly step

Inventive Principle:
Principle #5Merging (Combining)

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 reduces surface pressure and prevents damage by distributing force more evenly and eliminating the need for screw nut installation during assembly, ensuring improved performance and stability of the emergency running insert.

Implementation Method 1

The plate can preferably have a casing made of an elastic material, in particular in the form of a PU layer, so that there is a buffer layer which prevents stresses inside the partial elements of the rotor due to the different expansion behavior of different materials of partial element and plate

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2141032B1Runflat insert for vehicle wheel with locking means
Publication Date: 2010.03.31 EUROPLAST NYCAST
  • EP2141032B1 patent drawingFigure 1
  • EP2141032B1 patent drawingFigure 2
  • EP2141032B1 patent drawingFigure 3

AI summary

The bracing fail-safe insert (1) has a rim and pneumatic tire arranged on the rim, where two, particularly three circular segment-shaped subcomponents are provided. The subcomponents of the rotor (3) consist of a casting material, particularly plastic or a composite material. The tightener comprises screws, which connect both the subcomponents of the rotor with each other.