Modular Vehicle Safety Actuator With Adjustable Gas Chamber Volume

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Solution Overview

Problem

Existing safety devices in vehicles, such as hood lifters, require multiple actuators with different characteristics, leading to increased costs due to the need for separate toolings and dimensions.

Innovation Solution

A modular actuator design that allows adaptation of the actuator's characteristics by varying the volume of the gas chamber using interchangeable pistons and spacers, enabling customization of force, speed, and stroke length for specific applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple actuators with different characteristics are used to meet specific application requirements, then the actuator can be customized for force, speed and stroke length, but the production cost increases due to the need for separate toolings and dimensions

Engineering Contradiction:
Improveactuator characteristics adaptationVSAvoidproduction cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The actuator is divided into modular components: a standardized housing and interchangeable pistons with different characteristics. Each piston can be independently selected or customized to provide specific force, speed, and stroke length requirements while using the same housing tooling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A universal housing design is created that can accommodate multiple piston variants. The housing serves multiple functions: containing the gas generator, providing mounting interfaces, and working with different piston types to deliver various actuator characteristics without requiring separate toolings for each variant.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If the volume of the gas chamber is varied to change actuator characteristics, then the force and speed can be adapted, but this requires changing the housing dimensions which increases manufacturing complexity

Engineering Contradiction:
Improvegas chamber volume variationVSAvoidhousing dimension variations
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of varying housing dimensions to change gas chamber volume, the solution moves the variation to the piston dimension. The housing maintains fixed dimensions while the piston's internal gas chamber volume is adjusted by changing piston length or internal geometry, separating the dimensional stability requirement from the volume adaptation need.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The piston acts as an intermediary component between the standardized housing and the gas generator. By placing the gas chamber volume variation in the piston rather than the housing, the piston mediates between the need for standardized housing tooling and the need for varied gas chamber volumes across different applications.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables the creation of tailor-made actuators that meet specific application requirements while reducing production costs by using a single housing dimension and interchangeable components.

Implementation Method 1

a piston adapted to fit in the housing and being configured to be moved from a retracted position to an extended position, and a gas generator... the piston has a first end forming a pressure surface facing the first end of the housing... the gas generator is in fluid connection with the gas chamber

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Data Source

PatentEP4289685B1A safety device in a vehicle
Publication Date: 2025.04.30 AUTOLIV DEV AB
  • EP4289685B1 patent drawingFigure 1
  • EP4289685B1 patent drawingFigure 2a~2c
  • EP4289685B1 patent drawingFigure 3

AI summary

A safety device in a vehicle is provided. The safety device comprises a modular actuator (100) comprising a housing (1) having a first end (2), a piston (4) adapted to fit in the housing (1) and being configured to be moved from a retracted position to an extended position, and a gas generator (15). The piston (4) has a first end forming a pressure surface (6) facing the first end (2) of the housing (1). A gas chamber (8) is formed between the pressure surface (6) of the piston (4) and an inner wall of the first end (2) of the housing (1), and the gas generator (15) is situated in the gas chamber (8). The volume of the gas chamber (8) as seen in a condition when the piston (4) is in the retracted position may be selectively adapted by replacing a piston (4) having a first volume with a piston having a second volume, the second volume being different than the first volume; and/or arranging a spacer (25) in the gas chamber (4).