Electrodynamic Actuator Arms with Damping Material
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-strength metals used in electrodynamic actuators offer low damping, leading to unwanted vibrations and compromised sound quality due to high bending stress in the arm arrangement, especially at resonant frequencies, despite providing high output power and efficiency.
Innovation Solution
The use of metal arms with a fatigue strength of at least 370 N/mm2 and ultimate tensile strength of 1100 N/mm2, connected by a damping material with a tensile storage modulus of 0.1-6000 MPa and a tensile loss factor of at least 0.1, to reduce oscillation amplitude and minimize mechanical resistance while effectively damping unwanted vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-strength metals are used in the arm arrangement, then output power and efficiency are improved, but damping is reduced leading to unwanted vibrations
Solution Approach 1:
The arm arrangement uses a composite structure combining a metal core (providing strength and high output power) with a damping material coating (providing vibration damping). This composite approach allows simultaneous achievement of high power output and effective vibration suppression, resolving the contradiction between metal strength and damping performance.
Solution Approach 2:
The invention changes the physical parameters of the arm material by applying a damping material coating with specific loss factor characteristics onto the metal core. This parameter modification enables the arm arrangement to maintain structural integrity for high power while introducing sufficient damping to eliminate unwanted vibrations at resonant frequencies.
2Productivity
If high-strength metals are used in the arm arrangement, then mechanical resistance is reduced for high efficiency, but damping is insufficient causing vibrations at resonant frequencies
Solution Approach 1:
The composite arm structure with metal core and damping material coating allows the system to maintain low mechanical resistance for high efficiency while the damping material specifically targets and suppresses vibrations at resonant frequencies, resolving the efficiency-damping contradiction.
Solution Approach 2:
The damping material is applied locally on the surface of the metal core, providing targeted vibration damping at critical locations without significantly increasing mechanical resistance. This local quality enhancement allows the arm arrangement to maintain high efficiency while suppressing resonant vibrations.
3Productivity
If the arms are made thinner to reduce mechanical resistance, then efficiency is improved, but strength and damping are reduced leading to unwanted vibrations
Solution Approach 1:
The composite arm structure allows use of thinner metal cores (improving efficiency by reducing mechanical resistance) while the damping material coating compensates for the reduced inherent damping of thinner sections, preventing unwanted vibrations despite the reduced thickness.
Solution Approach 2:
By changing the surface properties through damping material coating, the invention compensates for the reduced structural parameters (thickness) of the arm, maintaining sufficient damping performance even with thinner arms that provide lower mechanical resistance for higher efficiency.
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 solution enhances damping in the arm arrangement, maintaining high output power and efficiency while significantly improving sound quality by reducing unwanted vibrations and mechanical resistance, even at small sizes.
Implementation Method 1
connected by means of a damping material with a tensile storage modulus of 0.1-6000 MPa and a tensile loss factor of at least 0.1
Implementation Method 2
a damping material with a tensile storage modulus of 0.1-6000 MPa and a tensile loss factor of at least 0.1
Implementation Method 3
arms which are made of a metal with a fatigue strength of at least 370 N/mm2 or an ultimate tensile strength of at least 1100 N/mm2
Implementation Method 4
metal with a fatigue strength of at least 370 N/mm2 or an ultimate tensile strength of at least 1100 N/mm2
Implementation Method 5
An electrical sound signal fed to the voice coil generates a force in the magnetic field of the magnet system and causes a movement between the coil arrangement and the magnet system
Data Source
AI summary
An electrodynamic actuator (1a . . . 1c) for a plate like structure (25) or membrane (2) is disclosed, which comprises a voice coil (7, 7a, 7b), a magnet system (8) and a plurality of arms (17a . . . 17t) coupling the voice coil (7, 7a, 7b) and the magnet system (8) in a movable manner. The arms (17a . . . 17t) are made of a metal with a fatigue strength of at least 370 N/mm2 or an ultimate tensile strength of at least 1100 N/mm2. Each of the arms (17a . . . 17t) comprises at least two arm sections (s, s1, s2), which are arranged movable to each other, and which are connected to each other by means of a damping material (18a . . . 18g) with a tensile storage modulus of 0.1-6000 MPa and a tensile loss factor of at least 0.1, each measured at room temperature of 20° C. Moreover the invention relates to speaker (5) and an electrodynamic transducer (26a, 26b) with such an electrodynamic actuator (1a . . . 1c) and a method of manufacturing an intermediate product for such an electrodynamic actuator (1a . . . 1c).