Capacitive Control Element Mounting for Short Actuation Path

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Solution Overview

Problem

Existing motor vehicle operating devices with pivotable elements face challenges in providing a simple, inexpensive, and stable mechanical structure that accurately detects pull and push operations with a short actuation path, while avoiding impermissible prestressing of force sensors and tolerances.

Innovation Solution

A device with a centrally mounted control element on a bearing point between vertical elongated holes, supported by pins with integrated force sensors, and a floating rotary mounting on vertical slots, allowing for precise detection of forces over a short actuation path, including the use of disk-shaped capacitive or piezoelectric sensors to distinguish between compressive and tensile forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a lever-like operating element with a long actuation path is used to provide haptic feedback, then the actuation path becomes perceptible to the user, but the actuation path length increases beyond what is desirable in every case

Engineering Contradiction:
Improvehaptic feedbackVSAvoidactuation path
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The patent replaces the traditional mechanical lever system with a capacitive sensor system. The operating element is a capacitive touch sensor that detects finger proximity or contact through electrical field changes rather than mechanical movement. This substitution eliminates the need for a long mechanical actuation path while maintaining user feedback through electrical rather than purely mechanical means.

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

Solution Approach 2:

The patent changes the detection parameter from mechanical displacement to electrical capacitance. By measuring changes in capacitance when a finger approaches or touches the operating element, the system can detect user input with minimal physical movement, thus reducing the actuation path length while still providing detectable feedback.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If a short actuation path is used to reduce unnecessary movement, then the actuation path length is minimized, but the force sensor may be prestressed outside its measuring range

Engineering Contradiction:
Improveactuation pathVSAvoidforce sensor measurement range
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent replaces the force sensor-based mechanical detection system with a capacitive sensor system. This eliminates the need for physical contact and force measurement, thereby avoiding the problem of sensor prestressing while maintaining short actuation path requirements. The capacitive sensor detects electrical field changes without requiring mechanical force application.

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

Solution Approach 2:

The patent introduces the electrical field as an intermediary between the user's finger and the sensor. Instead of direct mechanical contact that would prestress the sensor, the capacitive field acts as a mediator that transfers information about finger proximity or contact without requiring physical force, thus keeping the actuation path short while staying within sensor measurement ranges.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If a simple and inexpensive mechanical structure is used, then manufacturing cost is reduced, but the mounting precision and tolerance sensitivity increase

Engineering Contradiction:
Improvemanufacturing costVSAvoidmounting precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces complex mechanical mounting and positioning systems with a capacitive sensor system that is less sensitive to mechanical tolerances. Capacitive sensors can accurately detect finger input even with variations in mounting position, thereby reducing the need for high-precision mechanical manufacturing while maintaining functionality.

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

Solution Approach 2:

The patent changes the detection mechanism from mechanical position sensing to electrical capacitance sensing. This parameter change makes the system less sensitive to mechanical mounting tolerances, as capacitive detection can compensate for positional variations, thereby reducing manufacturing precision requirements while maintaining simple and inexpensive construction.

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

Enables accurate detection of operating element actuations with minimal perceivable movement, preventing force sensors from being prestressed outside their range, and allowing for multiple function triggers based on touch-sensitive capacitive surfaces, ensuring a stable and cost-effective design.

Implementation Method 1

the at least one force sensor is designed as a disk-shaped sensor that works according to a capacitive principle of action

Methodology Applied
Scientific EffectCapacitive principle: Capacitance

Implementation Method 2

Alternatively, the force sensor can also be designed as a piezoelectric sensor

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2984668B1Device for operating multiple functions in a motor vehicle
Publication Date: 2020.11.11 KOSTAL AUTOMOBIL ELECTRIC GMBH & CO KG
  • EP2984668B1 patent drawingFigure 1~2
  • EP2984668B1 patent drawingFigure 3~4
  • EP2984668B1 patent drawingFigure 5

AI summary

The invention relates to a device for operating multiple functions in a motor vehicle, comprising an operating element which is mounted in a pivotal manner about a rotational axle and can thereby be moved between at least two positions, wherein at least one of the positions is associated with a switching function. End sections of the rotational axle of the operating element are mounted in two elongated holes at two lateral mounting points, said holes being oriented along a vertical axis. The operating element is mounted in a centered manner at a central mounting point relative to the direction of the vertical axis, and the operating element is supported on two pins. The combination of mounting the operating element on two pins in a floating manner, mounting the operating element in a vertically centered manner, and rotatably mounting the operating element in a floating manner on two elongated vertical holes produces an operating element mounting which is clearly but not overly defined.