Elastic Leaf Spring Retaining Device for Vibratory Stability

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Solution Overview

Problem

Existing solutions for holding parts with a low form factor and high center of gravity in motor vehicles, such as electric vehicle chargers, face challenges in stability due to vibratory stresses and space constraints, with traditional methods like straps and screws lacking rigidity and adaptability.

Innovation Solution

A holding device featuring a flange with an elastically deformable leaf spring, tie rods, and a tensioning mechanism using screws and nuts, allowing for adjustable and removable attachment to the support, ensuring stability and adaptability to compact spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a strap is used to hold the part, then the device can be simple and adaptable, but the part becomes unstable under vibratory stresses

Engineering Contradiction:
Improvefixing device complexityVSAvoidpart stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the physical state of the fixing element from flexible (strap) to elastic-rigid (leaf spring). The leaf spring maintains flexibility for adaptation but provides rigid restoring force under vibration, resolving the contradiction between simplicity and stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The leaf spring introduces dynamic elasticity to the fixing system, allowing it to absorb and respond to vibratory stresses dynamically rather than relying solely on static friction or rigid constraint, thereby maintaining stability under vibration while preserving adaptability.

Inventive Principle:
Principle #15Dynamics

2Reliability

If material is added to create flat surfaces for screw fixing, then the part becomes stable, but the volume required exceeds available space

Engineering Contradiction:
Improvepart stabilityVSAvoidholding device volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The leaf spring acts as a thin elastic film that provides the necessary stabilizing force without requiring additional volumetric material. It bends and deforms to accommodate the part's geometry while maintaining contact pressure, eliminating the need for bulky flat surfaces.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention changes from rigid volumetric material (flat surfaces requiring screws) to elastic surface material (leaf spring). This parameter change allows the same stabilizing function to be achieved with minimal volume, fitting within the constrained space around the charger.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If screws are used to fix the holding device, then the part becomes stable, but assembly and disassembly become difficult due to limited access

Engineering Contradiction:
Improvepart stabilityVSAvoidassembly and disassembly ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts the fastening function from the leaf spring itself, allowing the elastic element to provide both the stabilizing force and the retention mechanism. The separate retaining element handles only the attachment function, simplifying the interaction and enabling easier assembly/disassembly through the limited access opening.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The fixing system is segmented into distinct functional elements: the leaf spring for elastic retention and the separate retaining element for mechanical attachment. This segmentation allows each component to be optimized independently, with the retaining element designed specifically for easy insertion and removal through the access opening.

Inventive Principle:
Principle #1Segmentation

4Reliability

If a rigid clamp is used to hold the part, then the part becomes stable, but the device cannot adapt to different part geometries

Engineering Contradiction:
Improvepart stabilityVSAvoidadaptability to part geometry
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The leaf spring changes the mechanical parameter of the fixing element from rigid to elastic. This elasticity allows the element to deform and adapt to different part geometries while maintaining sufficient contact pressure to prevent movement under vibration, simultaneously achieving stability and adaptability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The dynamic elasticity of the leaf spring allows it to conform to various part shapes during installation and maintain optimal contact pressure during operation. This dynamic adaptation capability enables a single design to work with different charger geometries while providing stable retention.

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 device provides robust and stable attachment of parts with a small form factor, maintaining stability under vibratory stresses and accommodating space constraints, while allowing for easy assembly and disassembly without tools.

Implementation Method 1

the flange comprises an elastically deformable element intended to exert pressure on the first face of the part when the flange is tensioned by the tensioning device. According to the invention, the elastically deformable element is formed by a leaf spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3577348B1Device for retaining a part on a support
Publication Date: 2023.03.01 RENAULT SA
  • EP3577348B1 patent drawingFigure 1~2
  • EP3577348B1 patent drawingFigure 3~5

AI summary

Retaining device intended to retain a part (10) on a support (11), comprising a strap (9) intended to be arranged in contact with a first face (10a) of the part (10) to be retained, the first face (10a) being opposite a second face (10b) of the part (10) which is arranged in contact with the support (11), a device (17) for attaching the strap (9) to the support (11) and a device (19) for tensioning the strap (9). Furthermore, the strap (9) comprises an elastically deformable element (12) intended to exert pressure on the first face (10a) of the part (10) when the strap (9) is tensioned by the tensioning device (19).