Linear Actuator Armature Weight Reduction via Local Quality
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Solution Overview
Problem
Existing linear actuators for active engine mounts face challenges in effectively managing high-frequency vibrations, leading to reduced performance and increased inertia, which affects their ability to suppress engine vibrations and noise transmission.
Innovation Solution
The linear actuator design incorporates a support element made of non-magnetic material with lower density than the armature, reducing the overall weight and inertia of the actuating element while maintaining magnetic functionality, achieved by minimizing the spatial extension of the armature and using lightweight materials like aluminum or fiber composites, and optimizing the cross-sectional shape to reduce volume without compromising magnetic force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the armature spatial extension is reduced to minimize weight, then the inertia is reduced and high-frequency behavior is improved, but the magnetic force may be compromised
Solution Approach 1:
The armature is designed with non-uniform cross-section where the thickness varies in different regions. The thicker regions are positioned where magnetic field lines are more dense to maintain magnetic force, while thinner regions reduce overall weight. This local variation in quality optimizes the balance between weight reduction and magnetic force maintenance.
Solution Approach 2:
The armature cross-section is designed asymmetrically with respect to radial thickness, being thicker in certain angular positions and thinner in others. This asymmetric design allows strategic placement of magnetic material where it is most effective for force generation while minimizing weight in less critical regions.
2Speed
If the armature volume is minimized to reduce inertia, then the resonance frequency increases, but the magnetic field interaction may be reduced
Solution Approach 1:
The armature thickness is locally optimized to maintain sufficient magnetic interaction volume in regions with higher field line density while minimizing material in regions with lower field interaction, thereby increasing resonance frequency without significantly compromising magnetic force.
3Manufacturing precision
If the armature is made smaller to reduce mass, then the reversal error is reduced, but the magnetic force generation capability may be affected
Solution Approach 1:
The armature design concentrates magnetic material in specific local regions where it is most effective for force generation and reversal control, rather than uniformly distributing material throughout the entire armature volume. This local optimization maintains magnetic force while enabling faster reversal with reduced mass.
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 enhances the actuator's performance at high frequencies by increasing the resonance frequency and reducing reversal errors, allowing for more efficient vibration suppression and noise reduction in vehicle engines.
Implementation Method 1
A linear actuator has a stator with a coil that can be fed with electric current for generating an electromagnetic field
Implementation Method 2
the relevant field lines run in a closed circle in the ferro-magnetic circuit of the linear actuator, in particular through the armature
Data Source
AI summary
A linear actuator for an active engine mount of a vehicle has a stator with a coil that can be fed with electric current for generating an electromagnetic field and an actuating element that is mounted in axially movable fashion with reference to the stator. The actuating element comprises an armature and a ram extending in axial direction and is so mounted in the stator by means of at least one spring element that it can be moved axially in frictionless fashion when the coil is fed with current. The actuating element comprises a support element of a non-magnetic light-weight construction material extending in radial direction between the armature and the ram. Advantageously, the armature is provided only in such regions where there run magnetically relevant field lines of the electromagnetic field of the coil.