Stamped Lock Reinforcement for Trunk Doors

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Solution Overview

Problem

Existing motor vehicle lock reinforcements for trunk doors are difficult to manufacture by stamping due to their hollow, deep shape and are subjected to high forces during trunk closure, leading to stress and making it challenging to mount the lock securely.

Innovation Solution

A lock reinforcement for trunk doors is created by bending a metal sheet, featuring a box-like shape with a planar attachment wall and a perpendicular receiving wall, joined by a connecting wall, with stiffening walls and assembly lugs for secure fixation and pre-holding of the lock, eliminating the need for stamping and providing enhanced endurance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the lock reinforcement is made with a hollow, deep shape to provide structural strength, then the strength and durability are improved, but the manufacturing complexity increases and stamping becomes difficult

Engineering Contradiction:
Improvelock reinforcement strengthVSAvoidstamping difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The lock reinforcement is divided into multiple planar components (attachment wall, receiving wall, connecting wall, stiffening walls) that are formed separately and then assembled together. This segmentation allows each component to be manufactured using simple stamping processes while the assembled structure provides the required hollow, deep shape and structural strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lock reinforcement components are nested together to form a box-like structure where the attachment wall, receiving wall, connecting wall, and stiffening walls create interconnected chambers and spaces. This nesting approach achieves the hollow, deep configuration needed for strength while maintaining manufacturability through progressive assembly of flat components.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If the lock reinforcement is subjected to high forces during trunk closure, then the structural integrity is tested, but the mounting difficulty and stress concentration increase

Engineering Contradiction:
Improveendurance under slammingVSAvoidlock mounting difficulty
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The lock reinforcement structure includes pre-formed assembly lugs and receiving walls that are prepared in advance during manufacturing. These features provide predetermined mounting locations and alignment guides that simplify the lock installation process while ensuring the structure is already optimized to handle closure forces before the lock is even mounted.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The reinforcement structure incorporates localized stiffening walls and strategically positioned assembly lugs at critical stress points. This local quality enhancement provides targeted strength where mounting forces and slamming forces are most concentrated, rather than uniformly strengthening the entire structure, thereby reducing overall complexity while improving reliability.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If the reinforcement structure is simplified for easy manufacturing, then the ease of manufacture is improved, but the pre-holding capability and structural stability are reduced

Engineering Contradiction:
Improveproduction simplicityVSAvoidlock pre-holding capability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The reinforcement is segmented into distinct functional walls (attachment wall for mounting to the door, receiving wall for lock engagement, connecting wall joining them, and stiffening walls for structural support). Each segment is optimized for its specific function while maintaining overall simplicity in manufacturing through stamping and assembly of flat components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reinforcement structure combines multiple sheet metal components with different orientations and functions to create a composite structure. The attachment wall provides mounting stability, the receiving wall provides lock engagement, and the stiffening walls provide structural rigidity, together creating a composite system that achieves both manufacturability and pre-holding capability.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3539806B1Arrangement of an openable body section of a motor vehicle with lock reinforcement
Publication Date: 2023.05.03 RENAULT SA
  • EP3539806B1 patent drawingFigure 1
  • EP3539806B1 patent drawingFigure 2~4
  • EP3539806B1 patent drawingFigure 5~7

AI summary

The invention relates to an arrangement (10) comprising a motor vehicle opening (1), in particular a trunk-type opening (20), a lock reinforcement (100) (30) fixed to this opening and a lock (30), the opening comprising a lining (22) having a first face (21) and a second face (23), the first face (21) being opposite the second face (23), a panel (26) comprising an inner face (25) and an outer face (27), the inner face (25) being opposite the outer face (27), the second face (23) of the lining (22) being fixed to the inner face (25) of the panel (26), the lock reinforcement (100) (30) being obtained by folding a metal sheet and the lock reinforcement (100) (30) being fixed to the first face (21) of the lining (22).