Brake Rotor Magnetic Domain Processing for Noise Damping

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Solution Overview

Problem

Brake rotors experience significant noise issues due to inadequate damping of resonant frequencies, leading to high warranty concerns for automotive OEMs, which existing technologies have not effectively addressed.

Innovation Solution

The method involves applying a controlled magnetic field to brake rotors using a current-carrying coil to increase magneto-mechanical damping by modifying the magnetic domain structure, including increasing closure domains and movement of non-180° domain walls, thereby reducing vibrational energy and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional brake rotor materials and designs are used, then manufacturing simplicity is maintained, but damping capacity is insufficient leading to high noise levels

Engineering Contradiction:

Improvebrake squeal noiseVSAvoidmaterial processing complexity

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies magnetic field parameters (strength, frequency, duration) to change the magnetic domain structure of the brake rotor material. By controlling parameters such as magnetic field intensity (e.g., 0.5-2.0 Tesla), frequency (e.g., 1-100 Hz), and exposure duration, the damping capacity is enhanced without changing the base material composition, thus reducing brake squeal noise while maintaining manufacturing simplicity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite magnetic domain structure within the existing brake rotor material by superimposing specific magnetic domain patterns (e.g., closure domains, 180-degree and non-180-degree domain walls) during controlled magnetic field exposure. This composite domain structure increases internal friction and damping capacity, effectively reducing noise without requiring material substitution or complex manufacturing processes

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If magnetic field strength is increased to improve damping, then vibrational energy absorption improves, but energy consumption and potential material damage increase

Engineering Contradiction:

Improvevibrational energyVSAvoidenergy consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic magnetic field exposure with controlled cycles (e.g., multiple on-off cycles at specific frequencies) to gradually reorient magnetic domains and increase damping capacity. This periodic action allows energy-efficient domain wall movement and closure domain formation over time, achieving effective vibrational energy absorption without requiring continuously high energy input that would cause material damage

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies magnetic field exposure that is sufficient to achieve the desired damping enhancement but not excessive. By optimizing the magnetic field parameters (strength, frequency, duration) to the minimum effective levels needed to create the desired domain structure, the patent achieves adequate vibrational energy absorption while minimizing energy consumption and avoiding material damage from overly intense exposure

Inventive Principle:

Principle #16Partial or excessive action

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 approach reduces brake squeal noise by up to 96% and increases fatigue strength of suspension springs by 5%, significantly improving the damping properties of brake rotors and related metal parts.

Implementation Method 1

placing said brake rotor in electrical contact with a current carrying coil and closing a circuit to apply current to said coil producing a magnetic field in said brake rotor

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Material damping involves internal friction generated in the material in response to a stress. Magneto-mechanical damping is one of the several mechanisms that generate internal friction

Methodology Applied

Scientific EffectMagneto-mechanical damping: Magnetoelastic Effects

Implementation Method 3

increasing numbers of closure domains absorbing vibrational energy, and movement on the non 180° domain walls

Methodology Applied

Scientific EffectMagnetic domain wall movement: Magnetic Hysteresis

Data Source

PatentEP2580361B1Magnetic and electrical processing of metals, metal alloys, metal matrix composite parts and components

Publication Date: 2021.08.04 RASSINI FRENOS S A DE

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AI summary

A method of processing a metal for improved damping of a metal part is provided. The method comprises placing the metal part inside a current carrying coil and closing a circuit for to apply current to the coil, thus producing a magnetic field in the metal part. Thereafter, the circuit is opened for a time and then the circuit is closed a second time to apply a second current to the coil. The circuit is then opened a second time and the metal part is removed from the current carrying coil.