Unitary Elastomer Overload Bumper for Vehicle Hood

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Solution Overview

Problem

The existing overrunning abutments for motor vehicle hoods are costly due to the high investment required for bi-injection molds, leading to increased unit costs and issues like parasitic metallic noises and paint peeling when the hood contacts the side wings.

Innovation Solution

A single injection mold is used to manufacture an overlapping abutment with a damping body and a quarter-turn type attachment member made of elastomeric material, reducing production costs and eliminating direct contact between the hood and side wings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If bi-injection mold is used to manufacture overrunning abutment, then the abutment can be made with complex structure (damping body + attachment member), but the manufacturing cost increases significantly

Engineering Contradiction:
Improveabutment structureVSAvoidmold investment cost
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The patent combines the damping body and attachment member into a single integrated component made of elastomeric material. The attachment member is molded directly as part of the damping body, eliminating the need for separate snap-fastening mechanisms and reducing mold complexity. This merging of functions allows single-injection molding while maintaining the required structural complexity for both damping and attachment purposes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses elastomeric material that provides both the damping function and the attachment function through its inherent properties. The material's elasticity allows it to serve as both the shock-absorbing body and the fastening element, eliminating the need for composite construction with multiple materials and simplifying the molding process to a single injection cycle.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If overlapping abutment is installed to prevent hood contact with side wings, then noise and paint peeling are prevented, but the unit cost of the abutment increases

Engineering Contradiction:
Improvenoise and paint peelingVSAvoidunit cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent employs a cost-effective design where the attachment member is molded from the same elastomeric material as the damping body, eliminating the need for expensive bi-injection molding. This simplified manufacturing approach reduces the unit cost significantly while maintaining the protective function against noise and paint peeling through the overlapping abutment structure.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If quarter-turn type attachment member is used, then the abutment can be securely fastened to the inner lining, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvefastening securityVSAvoidmold design
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The quarter-turn attachment member is integrated directly into the damping body as a single molded component. The attachment member's head with lateral branches and shoulders is formed as part of the damping body structure, eliminating the need for separate attachment components and simplifying the mold design while maintaining secure fastening capability through the quarter-turn mechanism.

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

The solution significantly reduces the unit cost of overrunning abutments and prevents noise and paint peeling by ensuring proper alignment and tension of the hood, enhancing user experience and vehicle quality.

Implementation Method 1

a damping body (11) made of elastomer

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

damping body made of elastomeric material

Methodology Applied
Scientific EffectEnergy absorption: Damping

Implementation Method 3

cooperating by form fitting with said orifice so as to ensure the locking in rotation

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 4

shoulders being capable of resting against the upper face of the circumference of said orifice

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP3969710B1Overload bumper for motor vehicle hood
Publication Date: 2023.07.12 STELLANTIS AUTO SAS
  • EP3969710B1 patent drawingFigure 1~2
  • EP3969710B1 patent drawingFigure 3~4
  • EP3969710B1 patent drawingFigure 5~6

AI summary

The invention relates to an overslam bumper for a motor vehicle hood comprising an exterior panel lined with an interior lining, the bumper comprising a vibration-damping body (11) which is made of elastomer and has an upper surface (12) provided to be placed against the lower surface of the interior lining, the bumper also comprising an attachment member (16) rigidly connected to the vibration-damping body (11) and capable of cooperating with an opening provided in the interior lining for attaching the bumper to the hood. The invention is characterised in that the quarter-turn attachment member (16) is formed unitarily with the vibration-damping body (11) from the same elastomer material as the latter.