Capacitive Steering Wheel Horn Sensor
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Solution Overview
Problem
Conventional steering arrangements for motor vehicles require a long actuation path for the horn, making it inconvenient for users to operate.
Innovation Solution
A capacitive sensor system with multiple electrically conductive surfaces on both the steering wheel body and actuating surface, allowing for a 'pathless' actuation by detecting changes in capacitance, ensuring reliable operation at any point on the surface, and optionally using a single conductive surface on one component to interact with multiple surfaces as a capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional mechanical switching element is used for the horn, then the horn can be activated, but the actuating surface requires a relatively long travel distance making operation inconvenient
Solution Approach 1:
The patent replaces the conventional mechanical switching element with a capacitive sensor that detects changes in capacitance rather than requiring mechanical movement. The actuating surface is formed as one electrode of the capacitor, and when pressed against the steering wheel body (forming the other electrode), it triggers the horn through electrical field detection rather than mechanical travel, thus eliminating the need for long actuation distance while improving ease of operation
Solution Approach 2:
The patent introduces an electrical field as an intermediary between the user's pressing action and the horn activation. The capacitive sensor detects the change in electrical field (capacitance) when the actuating surface is pressed, using this electrical intermediary to trigger the horn without requiring direct mechanical contact or long travel distance, thereby resolving the contradiction between ease of operation and actuation distance
2Reliability
If multiple electrically conductive surfaces are arranged on both steering wheel body and actuating surface, then reliable operation is ensured at any user position, but device complexity increases
Solution Approach 1:
The patent divides the actuating surface into multiple independently controllable capacitive sensor regions, each with its own electrically conductive surface. This segmentation allows different zones of the steering wheel to be activated independently, ensuring that regardless of user position, at least one sensor region will be properly actuated, thereby improving reliability while maintaining manageable complexity through modular sensor design
3Ease of manufacture
If a single electrically conductive surface interacts with multiple surfaces, then cost is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent designs one electrically conductive surface (typically on the actuating surface) to serve multiple functions by interacting with several different electrically conductive surfaces on the steering wheel body. This single multi-functional surface can detect presses from different locations and angles, reducing the total number of conductive surfaces needed and lowering manufacturing costs, while the multi-functionality is achieved through careful design of the electrical field detection range
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 simplifies the mechanical concept, reduces costs, enhances user comfort, and ensures reliable horn activation with a potentially shorter actuation stroke, improving usability and reliability.
Implementation Method 1
The two electrically conductive surfaces form a type of sensor surface, such that they act together as the electrodes of a capacitor. The switching signal is generated based on the change in capacitance of the capacitor when the actuating surface is actuated
Data Source
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AI summary
The steering arrangement or steering wheel (1) has a steering wheel body (2), a fixing surface (5) that is arranged at the steering wheel body and a shifting element. The shifting element has a capacitive sensor. An electrical conducting surface is arranged at the steering wheel body and fixing surface.