Torque Sensor Bar Magnets Steering Shaft Attachment

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Solution Overview

Problem

Existing torque sensors in steering systems face challenges in attachment to upper steering shafts and are costly due to the use of ring magnets.

Innovation Solution

A torque sensor design featuring a first rotor with apertures and bar magnets, a second rotor with tooth members, and Hall effect sensors to generate signals indicative of torque applied between the rotors, with a controller determining torque values from these signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ring magnets are used in torque sensors, then torque measurement capability is achieved, but manufacturing cost increases and attachment difficulty increases

Engineering Contradiction:
Improvetorque measurement capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive ring magnets with multiple inexpensive bar magnets that can be easily manufactured and attached. Each bar magnet is a simple, low-cost component that can be individually secured in aperture slots, making the overall torque sensor more cost-effective while maintaining functional capability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent divides a single ring magnet into multiple discrete bar magnets arranged around the first rotor. This segmentation allows each magnet to be independently positioned in apertures with aperture slots, simplifying attachment to the upper steering shaft and enabling easier manufacturing and assembly compared to a monolithic ring magnet structure.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If ring magnets are used in torque sensors, then torque measurement capability is achieved, but attachment to upper steering shaft becomes challenging

Engineering Contradiction:
Improvetorque measurement capabilityVSAvoidattachment to upper steering shaft
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent divides a single ring magnet into multiple discrete bar magnets arranged around the first rotor. This segmentation allows each magnet to be independently positioned in apertures with aperture slots, simplifying attachment to the upper steering shaft and enabling easier manufacturing and assembly compared to a monolithic ring magnet structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces aperture slots as an intermediary feature between the bar magnets and the upper steering shaft. These slots receive the bar magnets and provide a mechanical interface for secure attachment, facilitating easier installation and removal of the torque sensor on the steering shaft without requiring complex attachment mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design provides an improved, cost-effective torque measurement system that accurately determines torque applied to a vehicle's steering system, enhancing attachment efficiency and reducing manufacturing costs.

Implementation Method 1

first and second Hall effect sensors disposed in an open region of the second rotor proximate to the first rotor. The first and second Hall effect sensors generate first and second signals, respectively, indicative of an amount of torque applied between the first and second rotors

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP2455735B1Torque sensing system having torque sensor, and steering system
Publication Date: 2018.02.14 GM GLOBAL TECHNOLOGY OPERATIONS LLC
  • EP2455735B1 patent drawingFigure 1
  • EP2455735B1 patent drawingFigure 2~3
  • EP2455735B1 patent drawingFigure 4

AI summary

A torque sensing system having a torque sensor, and a steering system, are provided. The torque sensor includes a first rotor having apertures extending therethrough and bar magnets disposed in the apertures. The torque sensor further includes a second rotor defining an interior region with the first rotor being disposed in the interior region. The second rotor has tooth members extending toward the first rotor. The torque sensor further includes first and second Hall effect sensors disposed in an open region of the second rotor proximate to the first rotor. The first and second Hall effect sensors generate first and second signals, respectively, indicative of an amount of torque applied between the first rotor and the second rotor.