Magnetic Spring Damper Isolator for Engine Torsional Vibration
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Solution Overview
Problem
Existing torsional vibration dampers for vehicle engines face challenges with noise, weight, cost, and fatigue life, particularly with the introduction of start-stop systems, which traditional elastomeric and mechanical spring-based isolators fail to address effectively.
Innovation Solution
A magnetic isolator system using a plurality of magnets with like polarities to provide isolator functionality, allowing for a specific degree of rotation between the hub and pulley, offering a non-linear spring rate without the need for elastomeric or mechanical springs, thus reducing noise, weight, and material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If elastomeric rubber springs are used in isolator systems, then non-linear spring rate is provided, but fatigue life is limited and temperature performance varies
Solution Approach 1:
The patent replaces elastomeric rubber springs with a magnetic field-based isolator system. Magnets are positioned between the hub and pulley to create magnetic repulsion forces that provide the isolator function, eliminating the need for contact-based mechanical springs and their associated fatigue and temperature limitations.
Solution Approach 2:
The patent changes the physical state and properties of the isolator system by using magnetic field strength and polarity arrangements to achieve non-linear spring characteristics. By varying magnet positions, sizes, and polarities, the system achieves temperature-independent non-linear spring behavior that elastomeric materials cannot provide.
2Adaptability or versatility
If mechanical springs are used in isolator systems, then large free angle is provided for start/stop, but audible noise is produced and weight increases
Solution Approach 1:
The patent eliminates mechanical contact between spring components by using magnetic repulsion forces. The magnets create the necessary isolator effect without physical rubbing or contact, thereby eliminating audible noise while maintaining the large free angle required for start-stop operations.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the hub and pulley, replacing direct mechanical contact. This magnetic intermediary transmits the isolator function without requiring physical contact, thus eliminating noise while preserving the required range of motion.
3Reliability
If mechanical springs are used in isolator systems, then isolator functionality is provided, but manufacturing cost and material cost increase
Solution Approach 1:
The patent replaces complex mechanical spring assemblies with a simpler magnetic field-based system. This substitution eliminates the need for precision-machined spring cavities, nitriding processes, and complex seating arrangements, thereby reducing both material and manufacturing costs while maintaining isolator functionality.
Solution Approach 2:
The patent uses magnets that can be simpler and less expensive to manufacture than precision-machined mechanical spring components. The magnetic isolator system eliminates the need for expensive post-processing treatments like nitriding and complex assembly procedures.
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 magnetic isolator system provides a quiet, lightweight, and cost-effective solution with improved fatigue life and temperature-frequency characteristics, offering a large free angle for engine start/stop operations while maintaining effective vibration damping.
Implementation Method 1
The repulsive forces between the plurality of magnets allow a particular amount or degree of rotation of the hub relative to the pulley or vice versa
Data Source
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AI summary
Damper-isolators are disclosed that have a hub defining a bore for receiving a shaft, a pulley body mated to the hub to collectively define a magnet track that is concentric about the bore, a damper assembly operatively disposed between the hub and a belt engaging portion of the pulley body, a first magnet positioned within the magnet track and connected to the hub for rotation therewith, and a second magnet positioned within the magnet track and connected to the pulley body for rotation therewith. The first magnet and the second magnet are positioned with like polarities facing one another. A front end accessory drive system having one of the damper-isolators is also disclosed.