Segmented Crush Can Structure for Light-Collision Bonnet Protection

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Solution Overview

Problem

In the event of a light collision, the bonnet of an automobile is prone to deformation due to its low strength compared to the front-side frame, leading to high repair costs.

Innovation Solution

A vehicle-body structure is implemented, featuring a pair of rear-portion crush cans that maintain their shape until a first predetermined load is applied, and a pair of front-portion crush cans that deform at a lower load, positioning the bonnet on the vehicle rear side to avoid collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a bumper reinforcement is disposed on the inner side of a front bumper with crush cans to absorb impact load at light collision, then the front-side frame is protected from damage, but the bonnet deforms and requires expensive repair or replacement

Engineering Contradiction:

Improvefront-side frame protectionVSAvoidbonnet repair cost

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

The crush can is divided into two distinct segments: a front portion with lower strength designed to deform at smaller impact loads, and a rear portion with higher strength designed to maintain shape at light collision loads. This segmentation allows the front portion to absorb impact energy while preventing the bonnet from contacting the rear portion, thereby protecting the bonnet from damage without requiring expensive repairs.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the crush can are assigned different mechanical properties: the front portion has lower strength and yields at smaller loads, while the rear portion has higher strength and maintains structural integrity. This local differentiation in material properties enables the crush can to perform multiple functions: the front portion deforms to absorb energy, while the rear portion remains rigid to prevent bonnet contact and damage.

Inventive Principle:

Principle #3Local quality

2Shape

If the bonnet is positioned at the frontmost position to accommodate design requirements, then the vehicle front appearance is optimized, but the bonnet is more exposed to collision damage

Engineering Contradiction:

Improvevehicle front appearanceVSAvoidbonnet collision exposure

Core Design Contradiction:

ShapeVSObject-affected harmful factors

Solution Approach 1:

The crush can serves as an intermediary element positioned between the obstacle and the bonnet. During light collision, the crush can deforms to absorb impact energy, acting as a mediator that prevents direct contact between the obstacle and the bonnet. This allows the bonnet to be positioned at the frontmost location for optimal appearance while still being protected from collision damage through the intermediary crush can structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If a single crush can structure is used to absorb all impact loads, then the structure is simpler, but it cannot effectively protect the bonnet at light collision while maintaining strength for severe collision

Engineering Contradiction:

Improvecrush can structureVSAvoidbonnet protection effectiveness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The crush can is segmented into front and rear portions with different strength characteristics. The front portion is designed to deform at smaller impact loads, while the rear portion maintains structural integrity. This segmentation enables the crush can to reliably protect the bonnet at light collision by preventing contact, while still providing adequate strength for severe collision scenarios.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The structural parameters of the crush can are varied along its length: the front portion has lower strength parameters that allow deformation at small loads, while the rear portion has higher strength parameters that maintain rigidity. This parameter variation enables the crush can to effectively protect the bonnet at light collision by controlling the deformation behavior of different sections under different load conditions.

Inventive Principle:

Principle #35Parameter changes

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 configuration effectively absorbs impact loads during light collisions, preventing damage to the bonnet and reducing repair costs by minimizing deformation and damage to the bonnet.

Implementation Method 1

perform compressive deformation when the first predetermined load is applied

Methodology Applied

Scientific EffectCompression: Compression

Implementation Method 2

perform compressive deformation when a second predetermined load smaller than the first predetermined load is applied

Methodology Applied

Scientific EffectDeformation: Deformation

Data Source

PatentUS12202548B2Vehicle-body structure that supresses damage from a collision

Publication Date: 2025.01.21 MAZDA MOTOR CORP

AI summary

To suppress damage on a bonnet at light collision, a vehicle-body structure includes rear-portion crush cans that perform compressive deformation when a first predetermined load is applied, and front-portion crush cans that perform compressive deformation when a second predetermined load smaller than the first predetermined load is applied. A front portion of a bonnet is positioned on a vehicle rear side of front portions of the rear-portion crush cans.