Pyrotechnic Bolt Release for Vehicle Crash Energy Management

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Solution Overview

Problem

Existing connecting devices in motor vehicles fail to provide adequate occupant protection in various crash scenarios by not efficiently releasing structural members to reduce vehicle stiffness and absorb collision energy effectively.

Innovation Solution

A connecting device with a bolt joint system incorporating a pyrotechnical charge and igniter that, upon receiving an ignition signal, detonates to destroy the bolt joint connection, allowing a structural member to be released from the chassis, thereby reducing the vehicle's front end structure stiffness and enhancing occupant protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the vehicle structure maintains high stiffness through fixed bolt joint connections, then the structural strength and stability are improved, but the occupant protection in crash scenarios deteriorates due to excessive acceleration

Engineering Contradiction:
Improvestructural strengthVSAvoidoccupant acceleration
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The bolt joint system transitions from a static fixed connection to a dynamic releasable connection. The pyrotechnical charge enables the connection to change state from connected to released based on crash conditions, allowing the structure to adapt its stiffness dynamically to protect occupants

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the bolt joint system remains connected during crash, then the structural stability is maintained, but the collision energy absorption efficiency deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidcollision energy absorption
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The pyrotechnical charge is pre-positioned near the bolt joint system to enable rapid release action. Upon receiving an ignition signal during crash, it detonates to destroy the connecting function, allowing the structural member to be released and energy to be absorbed by deformation zones

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If a traditional sliding bolt mechanism is used for release, then the releasing function is achieved, but the occupant protection in various crash scenarios deteriorates due to insufficient protection

Engineering Contradiction:
Improvereleasing functionVSAvoidoccupant protection
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The mechanical sliding bolt release mechanism is replaced with a pyrotechnical charge-based destruction system. The pyrotechnical charge detonates to destroy the nut or bolt, providing a more reliable and rapid release mechanism that effectively protects occupants in various crash scenarios

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

The solution effectively reduces occupant acceleration and injury risk by adaptively releasing structural members during predicted crashes, allowing deformation zones to absorb collision energy more efficiently.

Implementation Method 1

said igniter being adapted to, when receiving an ignition signal, bring said charge to detonate, said pyrotechnical charge being located near the bolt joint system such that it, upon detonation, destroys the connecting function of the bolt joint system

Methodology Applied
Scientific EffectDetonation: Detonation

Data Source

PatentEP2143962B1Connecting device arranged in a motor vehicle and a method for controlling the same
Publication Date: 2011.11.02 AUTOLIV DEV AB
  • EP2143962B1 patent drawingFigure 1~2
  • EP2143962B1 patent drawingFigure 3a~3b
  • EP2143962B1 patent drawingFigure 3c

AI summary

The present invention relates to a connecting device (8) arranged in a motor vehicle (1) for releasably connecting a structural member (2) of the vehicle (1) to the vehicle chassis (3), said connecting device (8) comprising a bolt joint system (9). The connecting device (8) further comprises a pyrotechnical charge (23) and an igniter (23), said igniter (23) being adapted to, when receiving an ignition signal, bring said pyrotechnical charge (23) to detonate, said pyrotechnical charge (23) being located near the bolt joint system (9) such that it, upon detonation, destroys the connecting function of the bolt joint system (9), for releasing said structural member (2) from the chassis (3).