Flexible Magnet Assembly for Power Steering Sensors

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Solution Overview

Problem

Existing power steering systems face challenges in manufacturing cost and reliability due to the complex and expensive methods used for attaching permanent magnetic components to the steering shaft, which are prone to failure under mechanical and temperature stresses.

Innovation Solution

A magnet assembly using a magnetic or magnetizable flexible band applied to a support section of the steering shaft, wound in multiple layers for enhanced magnetic field strength and secured by adhesion, providing a durable and flexible solution that is insensitive to mechanical stresses and temperature variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate components are used to positively lock or bond magnetic rings to a carrier, then the magnetic component is securely fixed, but the manufacturing process becomes complex

Engineering Contradiction:

Improvesecure fixation of magnetic componentVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the carrier and magnetic ring into a single integrated component. The magnetic ring is formed by injection-molding magnetic particles into a cavity of the carrier, eliminating the need for separate fixation components and reducing manufacturing complexity while maintaining secure fixation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The magnetic ring is created as a composite material by injection-molding magnetic particles into a binding material matrix. This composite structure integrates the magnetic properties with the mechanical support function, eliminating the need for separate magnetic components and their associated fixation mechanisms.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a plastic material filled with magnetic particles is injection-molded to form a magnetic ring, then the magnetic component is integrated with the carrier, but the manufacturing process remains complex

Engineering Contradiction:

Improveintegration of magnetic component with carrierVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The carrier is designed to serve multiple functions: it provides mechanical support, defines the magnetic ring geometry through its cavity, and acts as the mold for forming the magnetic ring. This multi-functionality reduces the number of separate components and simplifies the manufacturing process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If adhesive bonding is used to attach the magnetic ring to the carrier, then the manufacturing process is simplified, but the durability under mechanical and temperature stresses is reduced

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoiddurability under stress

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The magnetic ring is formed as a composite material by injection-molding magnetic particles into a binding material. This creates an integrated structure where the binding material and magnetic particles are bonded at the molecular level, providing superior durability under mechanical and temperature stresses compared to adhesive bonding of separate components.

Inventive Principle:

Principle #40Composite materials

4Reliability

If a thick magnetic ring is used to provide sufficient magnetic field strength, then the magnetic field is strong enough for reliable scanning, but the sensor becomes sensitive to mechanical stresses and temperature variations

Engineering Contradiction:

Improvemagnetic field strengthVSAvoidsensitivity to mechanical stresses and temperature

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The magnetic ring is formed as a thin-walled structure by injection-molding into a cavity of the carrier. The thin-walled design reduces sensitivity to mechanical stresses and temperature variations while the integrated structure with the carrier maintains sufficient magnetic field strength for reliable scanning.

Inventive Principle:

Principle #30Flexible shells and thin films

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 reduces manufacturing costs and enhances the reliability of the power steering system by creating a durable, flexible magnetic element that maintains performance under varying conditions, suitable for both torque and steering angle sensors.

Implementation Method 1

a magnetic element which is rotationally fixed to the steering shaft and has a spatially fixed sensor unit cooperating therewith

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

attached to the steering shaft by adhesion to the carrier section

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3622253B1Power-steering with a sensor having a magnet assembly

Publication Date: 2021.12.15 THYSSENKRUPP PRESTA AG

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AI summary

The invention relates to a sensor having a magnet assembly, the magnet assembly comprising a magnet ring arranged on a carrier, which magnet ring is designed for arrangement on a shaft, the magnet ring being produced from a magnetic or magnetizable elastic strip, which is wrapped onto the carrier and fastened to the carrier by adhesion.