A flat earphone magnet unit with a magnetic conductive structure

Abstract

This utility model relates to a planar magnetic headphone magnet unit with a magnetically conductive structure. It includes a diaphragm, a permanent magnet array, and a support frame. The permanent magnet array consists of multiple strip-shaped permanent magnets symmetrically distributed on both sides of the diaphragm. A magnetically conductive alloy with a permeability μ≥10 is fixedly disposed on the outer side of the non-working surface of each strip-shaped permanent magnet. 4 A soft magnetic material with resistivity ρ≥50μΩ·cm has a U-shaped semi-enclosed cross-section that matches the magnet profile; the magnetic alloy is 0.1-0.5mm thick and has a 0.05-0.2mm gap with the magnet. Optionally, a hollow design is adopted. By constraining the magnetic field diffusion, the magnetic flux density is increased by 18% and the uniformity by 40%. At the same time, the alloy coating reduces the magnet breakage rate by 80%, achieving a synergistic breakthrough in acoustic performance and mechanical reliability.

Description

Technical Field

[0001] This utility model relates to the field of planar magnetic headphone technology, and specifically to a planar magnetic headphone magnet unit with a magnetic conductive structure. Background Technology

[0002] As an electroacoustic transducer based on the principle of electromagnetic drive, the core performance of planar magnetic headphones is directly related to the efficiency of the magnetic circuit system. In traditional designs, permanent magnet arrays are arranged in a parallel and symmetrical manner, driving the conductor layer to vibrate and produce sound by forming an alternating magnetic field on both sides of the diaphragm. However, this structure has inherent defects: the magnetic field lines at the edges of the magnets tend to diffuse into non-working areas, resulting in a reduction in the magnetic field strength acting on the diaphragm, and insufficient spatial uniformity, which in turn affects the consistency of the force on the diaphragm.

[0003] This magnetic field attenuation and distortion causes a triple problem: nonlinear increase in electromagnetic driving force, resulting in audible harmonic distortion under large signals; localized stress concentration in the diaphragm, disrupting high-frequency phase consistency; and peripheral leakage magnetic interference with surrounding circuits. The industry typically compensates for this by increasing the magnet volume or adding more magnetic poles, but this significantly increases device weight (by 20%-30%) and material costs (neodymium iron boron accounts for over 40% of the total cost), contradicting the trend towards lightweight portable devices. Therefore, there is an urgent need for a structure that can simultaneously achieve efficient magnetic field utilization, improved uniformity of magnetic field distribution, and mechanical reinforcement without increasing magnet volume. Utility Model Content

[0004] To address the aforementioned issues and optimize the process, this solution proposes adding a high-permeability metal layer to the non-working surface of the permanent magnet array (i.e., the side facing away from the diaphragm). This metal layer confines the magnetic field diffusion through a magnetic shielding effect, the mechanism of which involves two physical processes:

[0005] (1) By utilizing the high permeability of soft magnetic materials, the magnetic field lines that originally dissipated to the periphery of the magnet are redirected back to the working air gap region, thereby increasing the effective magnetic flux density.

[0006] (2) By adjusting the spatial distance and geometry between the metal layer and the magnet, the uniformity of the magnetic field distribution in the diaphragm plane is improved.

[0007] Specifically, this utility model provides a planar magnetic headphone magnet unit with a magnetically conductive structure, including a diaphragm, a permanent magnet array, and a support frame for mounting the permanent magnet array. The permanent magnet array is symmetrically distributed on both sides of the diaphragm to form a working air gap; the permanent magnet array is snapped and fixed to the support frame.

[0008] The permanent magnet array includes multiple strip permanent magnets, and a magnetically conductive alloy is fixedly disposed on each strip permanent magnet on the outer side of the non-working surface of the permanent magnet array opposite to the diaphragm; the magnetically conductive alloy is a soft magnetic alloy material, and its shape matches the contour of the non-working surface of the strip permanent magnet.

[0009] Furthermore, the magnetic permeability μ of the magnetic alloy is ≥10 4 And the resistivity ρ ≥ 50 μΩ·cm.

[0010] Furthermore, the cross-section of the magnetic alloy is U-shaped, and the thickness of the magnetic alloy is 0.1 mm to 0.5 mm.

[0011] Furthermore, the magnetically conductive alloy has a semi-enclosed structure, covering the outer surface and at least part of the end face of each bar permanent magnet in the permanent magnet array.

[0012] Furthermore, a gap is provided between the magnetic alloy and the non-working surface of the bar permanent magnet, the width of which is 0.05mm to 0.2mm.

[0013] Furthermore, the material of the magnetically conductive alloy is an iron-nickel alloy or an iron-silicon-aluminum alloy.

[0014] Furthermore, the magnetic alloy is fixed to the non-working surface of the bar permanent magnet by an adhesive or snap-fit ​​structure.

[0015] Furthermore, the length of the magnetically conductive alloy is longer than that of the bar permanent magnet, and both ends of the magnetically conductive alloy extend beyond the end face of the bar permanent magnet by 0.2-0.5 mm.

[0016] Furthermore, the magnetically conductive alloy has a hollow structure, and the shape of the hollow holes in the magnetically conductive alloy is hexagonal, rectangular, circular, or square.

[0017] Furthermore, the area of ​​the hollow holes in the magnetic alloy accounts for 50% to 70% of the surface area of ​​the magnetic alloy.

[0018] The beneficial effects of this utility model are as follows:

[0019] This structural improvement offers three advantages: First, the enhanced magnetic flux density improves the linearity of the electromagnetic driving force and diaphragm displacement, helping to reduce nonlinear distortion under large signals; second, a more uniform magnetic field distribution reduces local stress concentration on the diaphragm, improving phase consistency in the high-frequency band; and finally, constrained magnetic field diffusion reduces the impact of external electromagnetic interference on sensitive circuits. The additional eddy current losses introduced by the metal layer were also addressed during implementation.

[0020] While maintaining the original magnet volume, using a 0.3 mm thick soft magnetic alloy layer can increase the average magnetic induction intensity of the diaphragm region by about 18% (measured by a gaussmeter), and the field strength gradient at the edge of the magnetic pole decreases significantly (finite element simulation shows that the non-uniformity is improved from ±12% to ±7%).

[0021] The coating of the edges and corners of the bar permanent magnet with a magnetically conductive alloy reduces the drop breakage rate of black magnetic materials by 80% (industry average 5% → 1%), and the extended design at both ends increases impact resistance by 3 times. A high-resistivity alloy (ρ≥50μΩ·cm) combined with a hollow design controls eddy current losses to <3% (traditional magnetically conductive covers >8%), ensuring transient response speed. Performance upgrades are achieved without increasing magnet capacity, resulting in a 15%-20% weight reduction per unit, and the magnetically conductive alloy accounts for <5% of the material cost (compared to 40% for NdFeB). Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Appendix Figure 1 This is an exploded view of one side of the magnet unit of this utility model;

[0024] Appendix Figure 2 This is a cross-sectional view of the magnet unit of this utility model;

[0025] Appendix Figure 3 This is a schematic diagram showing the shape of the bar-shaped permanent magnet and the magnetically conductive alloy of this utility model;

[0026] Appendix Figure 4 This is a schematic diagram of the shape of the rectangular hollowed-out magnetic alloy of this utility model;

[0027] Appendix Figure 5 This is a schematic diagram showing the shape of other hollowed-out magnetic alloys of this utility model.

[0028] The components include: 1 diaphragm, 2 permanent magnet array, 21 strip permanent magnets, 211 non-working surface of the diaphragm, and 4 support frame. Detailed Implementation

[0029] Example 1:

[0030] See Figures 1 to 5 This utility model provides a planar magnetic headphone magnet unit with a magnetically conductive structure, including a diaphragm 1, a permanent magnet array 2, and a support frame 4 for mounting the permanent magnet array. The permanent magnet array 2 is symmetrically distributed on both sides of the diaphragm 1 to form a working air gap; the permanent magnet array 2 is snapped and fixed to the support frame 4.

[0031] The permanent magnet array 2 includes multiple strip permanent magnets 21. A magnetically conductive alloy 3 is fixedly disposed on each strip permanent magnet 21 outside the non-working surface 211 of the diaphragm 1 in the permanent magnet array 2. The magnetically conductive alloy 3 is a soft magnetic alloy material, and its shape matches the contour of the non-working surface of the strip permanent magnet 21.

[0032] Furthermore, the magnetic permeability μ of the magnetic alloy 3 is ≥10. 4 And the resistivity ρ ≥ 50 μΩ·cm.

[0033] Furthermore, the cross-section of the magnetic alloy 3 is U-shaped, and the thickness of the magnetic alloy 3 is 0.1 mm to 0.5 mm.

[0034] Furthermore, the magnetically conductive alloy 3 has a semi-enclosed structure, covering the outer surface and at least part of the end face of each bar permanent magnet in the permanent magnet array 2.

[0035] Furthermore, a gap is provided between the magnetically conductive alloy 3 and the non-working surface 211 of the bar permanent magnet 21, and the width of the gap is 0.05mm to 0.2mm.

[0036] Furthermore, the material of the magnetically conductive alloy 3 is an iron-nickel alloy or an iron-silicon-aluminum alloy.

[0037] Furthermore, the magnetic alloy 3 is fixed to the non-working surface of the strip permanent magnet 21 by an adhesive or snap-fit ​​structure.

[0038] Furthermore, the length of the magnetically conductive alloy 3 is longer than that of the bar permanent magnet 21, and both ends of the magnetically conductive alloy 3 extend beyond the end face of the bar permanent magnet 21 by 0.2-0.5 mm.

[0039] Furthermore, the magnetically conductive alloy 3 has a hollow structure, and the shape of the hollow holes in the magnetically conductive alloy 3 is hexagonal, rectangular, circular, or square.

[0040] Furthermore, the area of ​​the hollow holes in the magnetic alloy 3 accounts for 50% to 70% of the surface area of ​​the magnetic alloy 3.

[0041] Thus far, the description of the above embodiments has been provided for illustrative and descriptive purposes. This is not intended to be exhaustive or limiting of the present disclosure. Individual elements or features of particular embodiments are generally not limited to those particular embodiments, but may be interchanged and used in selected embodiments where applicable, even if not specifically shown or described. In many respects, the same elements or features may also be varied. Such variations are not considered a departure from this disclosure, and all such modifications are intended to be included within the scope of this disclosure.

[0042] Example embodiments are provided so that this disclosure will become thorough and will fully convey the scope to those skilled in the art. Numerous details, such as examples of specific parts, apparatus, and methods, are set forth to provide a thorough understanding of embodiments of this disclosure. It will be apparent to those skilled in the art that the specific details are not required, and the example embodiments may be implemented in many different forms, neither of which should be construed as limiting the scope of this disclosure. In some example embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

[0043] Technical terms are used herein for the purpose of describing specific exemplary embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a” and “the” as used herein may also refer to the plural forms. The terms “comprising” and “having” are inclusive and therefore specify the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or additional having of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. Unless expressly indicated in order of execution, the method steps, processes, and operations described herein are not to be construed as necessarily requiring performance in the specific order discussed and shown. It should also be understood that additional or optional steps may be employed.

Claims

1. A planar magnetic headphone magnet unit with a magnetically conductive structure, characterized in that: It includes a diaphragm (1), a permanent magnet array (2), and a support frame (4) for mounting the permanent magnet array. The permanent magnet array (2) is symmetrically distributed on both sides of the diaphragm (1) to form a working air gap. The permanent magnet array (2) is snapped and fixed to the support frame (4). The permanent magnet array (2) includes multiple strip permanent magnets (21). A magnetically conductive alloy (3) is fixedly disposed on each strip permanent magnet (21) outside the non-working surface (211) of the permanent magnet array (2) facing away from the diaphragm (1). The magnetically conductive alloy (3) is a soft magnetic alloy material, and its shape matches the contour of the non-working surface of the strip permanent magnet (21).

2. The planar magnetic headphone magnet unit with a magnetically conductive structure according to claim 1, characterized in that: Magnetic alloy (3) with permeability μ≥10 4 And the resistivity ρ ≥ 50 μΩ·cm.

3. The planar magnetic headphone magnet unit with a magnetically conductive structure according to claim 1, characterized in that: The cross-section of the magnetic alloy (3) is U-shaped, and the thickness of the magnetic alloy (3) is 0.1 mm to 0.5 mm.

4. The planar magnetic headphone magnet unit with a magnetically conductive structure according to claim 1, characterized in that: The magnetic alloy (3) has a semi-enclosed structure, covering the outer surface and at least part of the end face of each bar permanent magnet in the permanent magnet array (2).

5. The planar magnetic headphone magnet unit with a magnetically conductive structure according to claim 1, characterized in that: A gap is provided between the magnetic alloy (3) and the non-working surface (211) of the bar permanent magnet (21), the width of which is 0.05 mm to 0.2 mm.

6. The planar magnetic headphone magnet unit with a magnetically conductive structure according to claim 1, characterized in that: The magnetically conductive alloy (3) is made of iron-nickel alloy or iron-silicon-aluminum alloy.

7. The planar magnetic headphone magnet unit with a magnetically conductive structure according to claim 1, characterized in that: The magnetic alloy (3) is fixed to the non-working surface of the bar permanent magnet (21) by an adhesive or snap-fit ​​structure.

8. The planar magnetic headphone magnet unit with a magnetically conductive structure according to claim 1, characterized in that: The length of the magnetic alloy (3) is longer than that of the bar permanent magnet (21), and the two ends of the magnetic alloy (3) extend beyond the end face of the bar permanent magnet (21) by 0.2-0.5 mm.

9. The planar magnetic headphone magnet unit with a magnetically conductive structure according to claim 1, characterized in that: The magnetic alloy (3) has a hollow structure, and the hollow holes of the magnetic alloy (3) are hexagonal, rectangular, circular or square.

10. The planar magnetic headphone magnet unit with a magnetically conductive structure according to claim 9, characterized in that: The area of ​​the hollow holes in the magnetic alloy (3) accounts for 50% to 70% of the surface area of ​​the magnetic alloy (3).

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