Vehicle Bumper Crash Box Coupling Without Welding

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Solution Overview

Problem

The existing method of welding crash boxes to a crossmember in bumper assemblies is energy-intensive and complex, particularly when the crossmember has a U-shaped or hat-shaped cross-section, making detachment difficult and increasing production costs.

Innovation Solution

A bumper arrangement where crash boxes are coupled to a crossmember using extruded profiles with coupling channels, eliminating the need for material-bonded connections like welding, and utilizing a crossbeam with a web and legs that facilitate direct load transfer and increased stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If crash boxes are welded to the crossmember, then the connection strength is improved, but the manufacturing complexity and energy consumption increase

Engineering Contradiction:
Improveconnection strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The connection system is segmented into modular components: the crossmember with integrated coupling channels, the crash box with matching coupling geometry, and removable coupling means (bolts/screws). This segmentation replaces the monolithic welded joint with discrete, interchangeable parts that simplify manufacturing and assembly while maintaining connection strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Coupling means (bolts, screws, or pins) serve as intermediary elements between the crossmember and crash box. These intermediaries transmit loads between the two components without requiring direct material bonding, eliminating the complexity of welding processes while ensuring adequate connection strength through mechanical fastening.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If crash boxes are welded to the crossmember, then the structural integrity is improved, but the ease of manufacture deteriorates

Engineering Contradiction:
Improvestructural integrityVSAvoidease of manufacture
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The bumper assembly is divided into separately manufacturable components (crossmember, crash boxes, coupling means) that can be produced through cost-effective extrusion and standard fastening processes, then assembled without energy-intensive welding operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The welding process (thermal/mechanical system) is replaced with a mechanical fastening system using bolts, screws, or pins. This substitution eliminates the need for specialized welding equipment, reduces energy consumption, and simplifies the manufacturing process while maintaining structural integrity through proven mechanical connection methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If the crossmember has a U-shaped or hat-shaped cross-section, then the stability is improved, but the welding complexity increases

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

Solution Approach 1:

The coupling channels are merged directly into the crossmember's extruded profile structure. This integration allows the coupling features to be formed simultaneously with the crossmember during the extrusion process, eliminating separate welding operations and reducing manufacturing complexity while preserving the stabilizing U-shaped or hat-shaped cross-section.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If welding is used to connect crash boxes to the crossmember, then the connection reliability is improved, but the production cost increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The welding process is replaced with mechanical fastening using standard bolts, screws, or pins. This substitution eliminates costly welding operations, reduces production time, and lowers manufacturing costs while maintaining connection reliability through proven mechanical fastening methods that allow for easy assembly and disassembly.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach reduces production costs and simplifies assembly by eliminating the need for welding, while enhancing the stability and deformation behavior of the bumper assembly during crashes.

Implementation Method 1

A coupling means (13) engages at least partially in the first coupling channel (10) and connects the crash box (4) to the cross member (2)

Methodology Applied
Scientific EffectMechanical Fastening: Mechanical Fastener

Implementation Method 2

The crash box (4) has a profile extruded in the vertical direction (Z) of the vehicle

Methodology Applied
Scientific EffectExtrusion: Extrusion

Implementation Method 3

In the event of an impact, the kinetic energy is converted into deformation energy by the crash boxes

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP4707078A1Bumper arrangement for a motor vehicle
Publication Date: 2026.03.11 BENTELER AUTOMOBILTECHNIK GMBH
  • EP4707078A1 patent drawingFigure 1
  • EP4707078A1 patent drawingFigure 2a~2d
  • EP4707078A1 patent drawingFigure 3

AI summary

A bumper assembly (1) for a motor vehicle comprising a cross member (2) and a crash box (4) arranged in the region of each end (3) of the cross member (2) for coupling the bumper assembly (1) to a longitudinal member (21) of the motor vehicle, wherein the crash box (4) has a profile extruded in the motor vehicle vertical direction (Z). The crash box (4) has a first coupling channel (10, 11) extending in the motor vehicle vertical direction (Z), wherein a coupling means (13) engages at least partially in the first coupling channel (10, 11) and connects the crash box (4) to the cross member (2), wherein the crash box (4) has a second coupling channel (12) extending in the motor vehicle vertical direction (Z) at its end (22) facing away from the cross member (2) for connecting the crash box (4) to the longitudinal member (21).