Steering Wheel Capacitive Sensor Band for Hidden Contact Sensing

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Solution Overview

Problem

Existing proximity and contact sensor devices for motor vehicle steering wheels face issues such as an unpleasant appearance due to visible wires, increased costs and labor for cavity creation, inability to apply sensors to spokes, and susceptibility to disturbances.

Innovation Solution

A rectangular extendable band with flat conductive tracks covered by adhesive layers and protected by a removable slider, integrated into the steering wheel rim using capacitive multi-channel circuitry, allowing for capacitive sensing without visible wires and enabling application to spokes with reduced cost and disturbance prevention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a metal wire is wrapped about the steering wheel and covered with a sponge layer, then the appearance is improved, but the structure becomes more complex and costly

Engineering Contradiction:

ImproveappearanceVSAvoidstructure

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The invention extracts the wire from the structure entirely and replaces it with a flat conductive track system printed directly on a flexible support, eliminating the need for wire wrapping and sponge covering while maintaining the capacitive sensing function

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical wire-wrapping system is replaced with a printed circuit board approach where conductive tracks are created through printing and etching processes, substituting mechanical assembly with manufacturing processes

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Shape

If cavities are provided on the steering wheel to house the wire, then the appearance is improved, but the manufacturing cost and labor time increase

Engineering Contradiction:

ImproveappearanceVSAvoidmanufacturing cost

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

The invention eliminates the need for cavities by using a flat conductive track system that can be applied directly to the steering wheel surface, removing the requirement for structural modifications and cavity creation

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The flexible support with printed conductive tracks acts as a thin film that conforms to the steering wheel surface without requiring structural cavities, enabling direct mounting on the outer surface

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If a metal wire is used for the sensor, then the capacitive sensing function is achieved, but the wire cannot be applied to the spokes

Engineering Contradiction:

Improvesensing functionVSAvoidapplication area

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The flexible support allows the conductive track system to be applied to complex geometries including spokes and curved surfaces, providing the adaptability that rigid wire structures cannot achieve

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible support enables the sensor system to adapt to different steering wheel designs and geometries, including spokes, by conforming to the surface rather than requiring fixed wire routing

Inventive Principle:

Principle #15Dynamics

4Reliability

If a metal wire is used for the sensor, then the capacitive sensing is achieved, but the wire is susceptible to disturbances

Engineering Contradiction:

Improvesensing functionVSAvoiddisturbances

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention replaces the metal wire with a printed conductive track system that can be integrated with grounding and shielding structures, reducing susceptibility to electromagnetic disturbances

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The flat conductive tracks serve multiple functions including sensing, grounding, and shielding, providing integrated disturbance rejection that single-function wire systems cannot achieve

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 sleek appearance, reduces costs by a quarter compared to wire conductors, enables branching for multiple sensing zones, and effectively screens disturbances, allowing for reliable proximity and contact detection.

Implementation Method 1

The tracks 6, 6', 6" perform the function of plates of a capacitor used as the sensitive element for proximity/contact sensing

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2790995B1Proximity and contact sensor device in motor vehicle steering wheels.

Publication Date: 2016.10.26 I R C A S P A IND RESISTENZE CORAZZATE E AFFINI

Figure 1~2

AI summary

A proximity and contact sensor device in motor vehicle steering wheels, characterised by comprising an extendable band (2), the length of which is slightly less than the circumference of the steering wheel and of which one surface has fixed to it at least one conductive track (6, 6', 6") covered with a biadhesive layer (14), said conductive track consisting of a flat metal path obtained by treating a metal sheet applied to said extendable band, said conductive track being connected to a multi-channel capacitive sensor circuit (8) connected by a field bus (10) to the vehicle control unit (12)..