Steering Device Horn Activation via Pressure Sensor

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Solution Overview

Problem

Conventional steering devices require large gaps between the horn cover and the steering wheel surface for horn signal activation, leading to visual and cleaning issues, and have complex, expensive mechanisms with multiple horn contact pairs.

Innovation Solution

A steering device with a pressure sensor connected to an air-filled chamber that detects pressure fluctuations caused by external impacts, eliminating the need for large gaps and complex mechanisms, using a piezoresistive pressure sensor for reliable and compact horn signal activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional horn mechanism with multiple horn contact pairs and prestressed tilting or sliding bearings is used, then horn signal activation is achieved, but the device complexity increases and manufacturing cost increases

Engineering Contradiction:
Improvehorn signal activationVSAvoidhorn mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of horn activation from the complex mechanical contact mechanism and implements it through a simplified pressure sensor system. The pressure sensor detects pressure changes in the air-filled chamber caused by cover deformation, eliminating the need for multiple horn contact pairs and prestressed bearings, thus reducing device complexity while maintaining activation reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical horn contact system with an electronic pressure sensing system. Instead of using mechanical contacts and tilting/sliding bearings to activate the horn, the system uses a pressure sensor that detects pressure fluctuations in the air-filled chamber, substituting a mechanical system with an electronic one to reduce complexity

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

2Ease of operation

If large gaps are provided between the cover and the steering wheel surface surrounding the cover, then horn signal triggering is enabled, but visual appearance deteriorates and cleaning difficulty increases

Engineering Contradiction:
Improvehorn signal triggeringVSAvoidsoiling and visual disturbance
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent changes the operational parameter from requiring large mechanical displacements (cover tilting or sliding) to detecting small pressure changes in the air-filled chamber. The pressure sensor can detect pressure fluctuations caused by minimal cover deformation (less than 1 mm), allowing the cover to be positioned close to the steering wheel surface without affecting horn activation functionality

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

The solution provides a simple, reliable, and compact horn activation system that varies horn sound based on impact force, integrating the horn module into the gas bag module for reduced assembly complexity and minimal gap requirements.

Implementation Method 1

The pressure sensor is preferably a piezoresistive pressure sensor that changes its electrical resistance when the pressure changes

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 2

the pressure sensor already detects pressure waves in the chamber caused by an external impact on the cover

Methodology Applied
Scientific EffectPressure wave propagation: Shock Wave

Data Source

PatentEP3604036B1Steering device for a vehicle and gas bag module for such a steering device
Publication Date: 2021.03.31 DALPHI METAL ESPANA SA
  • EP3604036B1 patent drawingFigure 1~2
  • EP3604036B1 patent drawingFigure 3~4
  • EP3604036B1 patent drawingFigure 5~6

AI summary

The invention relates to a steering device (12) for a vehicle, comprising a steering axis (A) about which the steering device (12) is rotatable, a cover (28) for triggering a horn signal, an air-filled chamber (26) adjacent to the cover (28), a pressure sensor (14) connected to the chamber (26) for detecting pressure fluctuations in the chamber (26), and an electronic control unit (30) electrically connected to the pressure sensor (14) for activating a vehicle horn (32) depending on the detected pressure fluctuations. The invention further includes a gas-bag module (10) for such a steering device (12).