Torque Sensor Shielding Static Electricity and Noise

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Solution Overview

Problem

Conventional torque sensors using magnetic sensors are prone to damage and malfunction due to electrostatic energy and noise, as these can pass through the sensor body, causing dielectric breakdown or erroneous detection.

Innovation Solution

The detection device incorporates magnetism collection rings and a shielding member to direct static electricity and noise to a grounded member, preventing them from passing through the sensor body by forming a conductive path with the lowest resistance, thus protecting the sensor from damage and ensuring accurate magnetic flux detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the magnetic sensor is disposed in the magnetic flux path for detection, then the sensor can detect magnetic flux density accurately, but static electricity and noise can pass through the sensor causing damage or malfunction

Engineering Contradiction:
Improvemagnetic flux detection accuracyVSAvoidsensor damage resistance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent divides the sensor assembly into functionally separate components: the magnetic sensor element for detection and the conductive member (shielding structure) for electrostatic protection. This segmentation allows the sensor to be positioned in the magnetic flux path for accurate detection while the conductive member intercepts static electricity and noise before they reach the sensor, resolving the contradiction between detection accuracy and damage resistance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conductive member acts as an intermediary between the magnetic flux path and the magnetic sensor. It is positioned to intercept static electricity and electromagnetic noise, providing a protective barrier that allows the sensor to remain in the magnetic flux path for accurate detection without being exposed to harmful electrical disturbances

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a conductive path for static electricity is provided through the sensor body, then electrostatic energy can be discharged, but the sensor may still suffer dielectric breakdown or noise interference

Engineering Contradiction:
Improveelectrostatic discharge capabilityVSAvoiddielectric breakdown and noise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the electrostatic protection function from the sensor body itself and assigns it to a separate conductive member (shielding structure). This conductive member is specifically designed to intercept and discharge static electricity through a dedicated path that does not involve the sensor's dielectric components, thereby preventing dielectric breakdown while still providing electrostatic discharge capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The conductive member converts potentially harmful static electricity and electromagnetic noise into a beneficial protective mechanism. By providing a low-resistance path for electrostatic discharge through the conductive shielding structure, the system safely dissipates harmful electrical energy before it can damage the sensor, transforming a harmful factor into a protective feature

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

This configuration effectively restricts damage to the sensor and prevents malfunction by allowing static electricity and noise to escape to the ground without passing through the sensor body, ensuring reliable torque detection in applications like electric power steering systems.

Implementation Method 1

a magnetism-collecting ring for collecting magnetic flux generated by the member

Methodology Applied
Scientific EffectMagnetic flux collection: Magnetic Field

Implementation Method 2

The Hall IC includes an element part that detects magnetic flux

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP3396343B1Torque sensor
Publication Date: 2021.10.06 DENSO CORP
  • EP3396343B1 patent drawingFigure 1
  • EP3396343B1 patent drawingFigure 2
  • EP3396343B1 patent drawingFigure 3

AI summary

A detection device includes a conductive member, a facing member, and a sensor portion. The conductive member is provided to be conductive to a grounded member having a ground potential. The sensor portion includes a sensor element, a sensor main body, and a grounded terminal. The sensor element is disposed in a sensor placement region which is located between the conductive member and the facing member and in which a distance between the conductive member and the facing member is shortest. The conductive member is provided to be conductive to the grounded terminal or a grounded wiring portion connected to the grounded terminal in a conductive region different from the sensor placement region. Accordingly, static electricity and noise escape to the grounded member without passing through the sensor main body. Therefore, damage to and malfunction of the sensor are restricted.