Vehicle Power Unit Mounting Bracket with Fragile Portions

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Solution Overview

Problem

Existing power unit mounting structures in fuel cell vehicles are complex and costly, and may fail to absorb collision energy effectively due to non-breakage of attaching brackets during front collisions, leading to inadequate deformation of the vehicle body frame.

Innovation Solution

A power unit mounting structure featuring a sub frame with attaching brackets that have fragile portions which break upon impact, allowing the power unit to detach and absorb collision energy, while simplifying the manufacturing process and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the attaching bracket is designed to break during front collision to absorb energy, then collision energy absorption is improved, but the structure becomes more complex and costly

Engineering Contradiction:

Improvecollision energy absorptionVSAvoidattaching bracket structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The attaching bracket incorporates fragile portions with reduced cross-sectional area or weakened material properties at specific locations. These portions are designed to break at predetermined stress thresholds during front collision, enabling energy absorption through controlled fracture rather than requiring complex multi-component structures.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The attaching bracket is divided into distinct functional zones: robust portions that maintain structural integrity during normal operation and fragile portions that are designed to break during collision. This segmentation allows the single bracket to perform both support and energy absorption functions without requiring multiple separate components.

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If the attaching bracket is designed to break during front collision, then collision energy absorption is improved, but manufacturing cost increases

Engineering Contradiction:

Improvecollision energy absorptionVSAvoidmanufacturing cost

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The fragile portions are created by modifying geometric parameters (reducing cross-sectional area) or material parameters (using softer material) at specific locations of the bracket. These modifications can be achieved through standard manufacturing processes such as casting, forging, or machining, avoiding the need for complex assembly of multiple parts and reducing overall manufacturing cost.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The function of energy absorption is merged into the existing attaching bracket structure rather than being implemented through a separate safety device. The fragile portions are integrated directly into the bracket body, eliminating the need for additional components and reducing assembly complexity and manufacturing cost.

Inventive Principle:

Principle #5Merging (Combining)

3Strength

If a robust attaching bracket is used to ensure structural strength, then structural integrity is improved, but collision energy absorption capability deteriorates

Engineering Contradiction:

Improveattaching bracket strengthVSAvoidcollision energy absorption

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The attaching bracket exhibits non-uniform properties: robust portions with high strength and stiffness for normal load bearing, and fragile portions with reduced strength for controlled breakage during collision. This local differentiation of mechanical properties allows the single component to provide both structural support and energy absorption functions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The attaching bracket transitions from a static load-bearing structure to a dynamic energy-absorbing device during collision. The fragile portions are designed to fail at specific stress thresholds, transforming the bracket from a rigid support structure to a controlled fracture mechanism that absorbs collision energy through deformation and breakage.

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 structure enables efficient absorption of collision energy, simplifies manufacturing, and reduces costs by allowing the power unit to detach easily during front collisions, enhancing safety and economic viability.

Implementation Method 1

the shaft supporting portion of the attaching bracket has fragile portions which break or deform when the impact is applied such that the arm of the power unit shifts to the front direction

Methodology Applied

Scientific EffectImpact force: Impact Force

Data Source

PatentUS10071772B2Power unit mounting structure

Publication Date: 2018.09.11 HONDA MOTOR CO LTD

AI summary

A power unit mounting structure of a vehicle includes a power unit 100, a sub frame 200 disposed below the power unit 100 in the vehicle height direction and at least one attaching bracket 220 for attaching the power unit 100 on the sub frame 200, the power unit 100 has an arm 210 extended from the main body portion thereof to the attaching bracket 220, a tip portion of the arm 210 is axially supported on a pair of shaft supporting portions 221 of the attaching bracket 220 with a shaft member 213 extended to the width direction of the vehicle, and the shaft supporting portion 221 of the attaching bracket 220 has fragile portions 222, 223 which break when the impact is applied such that the aria 210 of the power unit 100 shifts to the front direction.