A double magnetic circuit high magnetic flux density magnetic circuit structure of bone conduction speaker

Abstract

The application belongs to the technical field of loudspeakers, and particularly relates to a double-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker. The technical scheme is as follows: a double-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker, comprising an upper outer ring magnet, an outer ring magnetic conducting member, a lower outer ring magnet, an upper inner ring magnet, an inner ring magnetic conducting member, a lower inner ring magnet and a voice coil; the upper outer ring magnet, the outer ring magnetic conducting member and the lower outer ring magnet form an outer ring magnetic circuit system, the upper inner ring magnet, the inner ring magnetic conducting member and the lower inner ring magnet form an inner ring magnetic circuit system, and the voice coil is arranged in an annular magnetic gap formed between the outer ring magnetic circuit system and the inner ring magnetic circuit system. The application provides the double-magnetic-circuit high-flux-density magnetic circuit structure of the bone conduction loudspeaker, which can guide to improve the magnetic flux density of the magnetic gap and improve the driving efficiency through a more reasonable magnetic circuit structure and magnetic conducting structure.

Description

Technical Field

[0001] This invention belongs to the field of loudspeaker technology, and specifically relates to a dual magnetic circuit high flux density magnetic circuit structure for a bone conduction loudspeaker. Background Technology

[0002] Bone conduction loudspeakers are acoustic loudspeaker units that convert electrical signals into mechanical vibrations and transmit them to the auditory system through the human skeleton. They are widely used in open-back headphones and sports wearable devices. Unlike traditional dynamic loudspeakers, which mainly rely on a diaphragm to push air to generate sound pressure, bone conduction loudspeakers typically need to output higher mechanical vibration forces and displacements within a limited volume, placing higher demands on the energy conversion efficiency, magnetic field strength, and linear stability of the drive system.

[0003] Existing bone conduction loudspeakers mostly employ a magnetic circuit system consisting of a permanent magnet, a magnetic conductor, and a voice coil. The permanent magnet provides a constant magnetic field, the magnetic conductor forms a closed magnetic circuit and guides the magnetic flux, and the voice coil is placed in the magnetic gap. When the voice coil is energized, it generates a Lorentz force in the magnetic field, thereby driving the transmission component to vibrate and achieve bone conduction output. Because bone conduction products are often limited by wearing comfort and size, the magnetic circuit structure usually needs to form the highest possible magnetic flux density in the magnetic gap within a small space to improve driving efficiency, reduce power consumption, and improve output capabilities at different frequency bands.

[0004] The magnetic circuit structure of existing bone conduction loudspeakers usually uses a single magnetic circuit or a relatively simple combination of magnet and magnetic conductor to form a working magnetic gap at the voice coil. However, due to the constraints of miniaturization and wearing comfort, the volume of the magnet and the cross-sectional area of ​​the magnetic conductor path are limited, making it difficult for the magnetic flux to be fully concentrated in the magnetic gap area. This results in limited space for increasing the magnetic flux density in the magnetic gap, which in turn leads to a smaller Lorentz force generated per unit current and lower driving efficiency.

[0005] At the same time, due to the unreasonable magnetic reluctance distribution in the magnetic flux circuit, it is common for magnetic flux to be dispersed or even leaked in the non-working area, which reduces the effective magnetic flux utilization rate and makes it difficult to concentrate the limited magnetic energy on the voice coil working area, thus limiting the output capability under the same power consumption conditions.

[0006] In addition, the magnetic field distribution in the magnetic gap region of the existing structure is often non-uniform. The force on the voice coil is prone to fluctuate with position changes during the reciprocating motion, resulting in insufficient driving linearity and stability. This manifests as unbalanced output at different frequency bands, increased distortion or decreased efficiency under large amplitude conditions.

[0007] In summary, existing bone conduction loudspeaker magnetic circuit structures cannot simultaneously achieve concentrated magnetic flux distribution and high magnetic gap flux density within a limited space, nor can they balance driving efficiency, output performance, and linear stability. Summary of the Invention

[0008] To address the aforementioned problems in the existing technology, the present invention aims to provide a dual-magnetic-circuit high-flux-density magnetic circuit structure for bone conduction loudspeakers. This structure can guide and enhance the magnetic flux density in the gap and improve driving efficiency through a more rational magnetic circuit structure and magnetic guiding structure. It also solves the problem that existing bone conduction loudspeaker magnetic circuit structures cannot simultaneously achieve concentrated magnetic flux distribution and high magnetic flux density in a limited space, and it is also difficult to balance driving efficiency, output performance, and linear stability.

[0009] The technical solution adopted in this invention is as follows: A dual-magnetic-circuit high-flux-density magnetic circuit structure for a bone conduction loudspeaker includes an upper outer ring magnet, an outer ring magnetic conductor, a lower outer ring magnet, an upper inner ring magnet, an inner ring magnetic conductor, a lower inner ring magnet, and a voice coil. The upper outer ring magnet, the outer ring magnetic conductor, and the lower outer ring magnet form an outer ring magnetic circuit system, and the upper inner ring magnet, the inner ring magnetic conductor, and the lower inner ring magnet form an inner ring magnetic circuit system. The voice coil is arranged in the annular magnetic gap formed between the outer ring magnetic circuit system and the inner ring magnetic circuit system.

[0010] The magnet assembly is connected to the fixed structure through a suspension system. After an audio current is passed through the voice coil, it generates an electromagnetic interaction with the magnetic field where the magnet assembly is located, thereby driving the magnet assembly to vibrate in a predetermined direction under the support and guidance of the suspension system.

[0011] This invention establishes a coaxial outer and inner magnetic circuit system, which, together with the outer and inner magnetic guide components, form a low-resistivity closed magnetic circuit. This allows for concentrated distribution and effective utilization of magnetic flux within the annular magnetic gap region corresponding to the voice coil, thereby increasing the effective magnetic flux density and utilization rate within the magnetic gap. Compared to single magnetic circuit structures or simple combinations of magnets and guide components, this invention enhances the working magnetic field and reduces leakage and ineffective flux loss within a limited structural size.

[0012] Compared to existing bone conduction loudspeakers, this invention, by employing a structure combining a long voice coil and a short magnetic gap, ensures that the voice coil continuously receives a relatively stable electromagnetic driving force throughout the entire movement process, thereby improving the Lorentz force output level and ultimately enhancing the driving efficiency and output performance of the bone conduction loudspeaker.

[0013] This invention forms a superimposed or synergistic magnetic field distribution at the annular magnetic gap by the outer and inner magnetic circuit systems, which helps to improve the uniformity and stability of the magnetic field in the magnetic gap, reduce the fluctuations caused by the force changing with position during the reciprocating motion of the voice coil, thereby improving the driving linearity and working stability, reducing distortion and improving the output consistency at different frequency bands.

[0014] In a preferred embodiment of the present invention, a voice coil skeleton is connected to the voice coil. The voice coil skeleton is used to stably support and position the voice coil, and to efficiently transmit the driving force generated by the voice coil to the bone conduction vibration transmission component, thereby further improving energy transfer efficiency and structural reliability.

[0015] As a preferred embodiment of the present invention, one end of the voice coil skeleton extends out of the annular magnetic gap formed between the outer magnetic circuit system and the inner magnetic circuit system.

[0016] As a preferred embodiment of the present invention, the voice coil is wound around the outer periphery of the voice coil frame or the inner periphery of the voice coil frame.

[0017] As a preferred embodiment of the present invention, the voice coil skeleton may be cylindrical, annular, frame-like, or a partially load-bearing structure.

[0018] As a preferred embodiment of the present invention, the voice coil has one or more winding layers, and the winding method of the voice coil is either single winding or multiple winding, in order to meet different driving requirements.

[0019] In a preferred embodiment of the present invention, the upper outer ring magnet, the outer ring magnetic conductor, the lower outer ring magnet, the upper inner ring magnet, the inner ring magnetic conductor, and the lower inner ring magnet constitute a magnet assembly. The magnet assembly is connected to the voice coil frame via a suspension system. The voice coil frame is fixedly mounted on a fixed structure, and the magnet assembly is connected to the fixed structure via the suspension system.

[0020] In a preferred embodiment of the present invention, the upper outer ring magnet is correspondingly arranged with the upper inner ring magnet, the outer ring magnetic conductor is correspondingly arranged with the inner ring magnetic conductor, and the lower outer ring magnet is correspondingly arranged with the lower inner ring magnet.

[0021] As a preferred embodiment of the present invention, the outer ring magnetic conductor and the inner ring magnetic conductor are integral magnetic conductors, split magnetic conductors, or magnetic conductor structures formed by combining multiple magnetic conductor components.

[0022] As a preferred embodiment of the present invention, the number of the upper outer ring magnet, the lower outer ring magnet, the upper inner ring magnet, and the lower inner ring magnet are one or more. That is, the number, shape, polarity arrangement, and corresponding positional relationship of the magnets of the upper outer ring magnet, the lower outer ring magnet, the upper inner ring magnet, and the lower inner ring magnet can all be adjusted according to the magnetic field strength, volume constraints, and performance requirements of the target product.

[0023] The beneficial effects of this invention are as follows: 1. This invention establishes a coaxial outer and inner magnetic circuit system, which, in conjunction with the outer and inner magnetic guide components, forms a low-resistivity closed magnetic circuit. This allows for concentrated distribution and effective utilization of magnetic flux within the annular magnetic gap region corresponding to the voice coil, thereby increasing the effective magnetic flux density and flux utilization rate within the magnetic gap. Compared to a single magnetic circuit structure or a simple combination of magnets and guide components, this invention can enhance the working magnetic field and reduce leakage flux and ineffective flux loss within a limited structural size.

[0024] 2. This invention forms a superimposed or synergistic magnetic field distribution at the annular magnetic gap by the outer and inner magnetic circuit systems, which helps to improve the uniformity and stability of the magnetic field in the magnetic gap, reduce the fluctuations caused by the force changing with position during the reciprocating motion of the voice coil, thereby improving the driving linearity and working stability, reducing distortion and improving the output consistency at different frequency bands. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a cross-sectional view of the present invention; Figure 3 This is a schematic diagram of surface magnetic flux density; Figure 4 This is a schematic diagram of the surface magnetic flux density lines.

[0026] In the diagram: 1-Upper outer ring magnet; 2-Outer ring magnetic conductor; 3-Lower outer ring magnet; 4-Upper inner ring magnet; 5-Inner ring magnetic conductor; 6-Lower inner ring magnet; 7-Voice coil; 8-Voice coil frame. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0029] like Figure 1 and Figure 2As shown, the dual-magnetic-circuit high-flux-density magnetic circuit structure of the bone conduction loudspeaker in this embodiment includes an upper outer ring magnet 1, an outer ring magnetic conductor 2, a lower outer ring magnet 3, an upper inner ring magnet 4, an inner ring magnetic conductor 5, a lower inner ring magnet 6, and a voice coil 7. The upper outer ring magnet 1, the outer ring magnetic conductor 2, and the lower outer ring magnet 3 form the outer ring magnetic circuit system, and the upper inner ring magnet 4, the inner ring magnetic conductor 5, and the lower inner ring magnet 6 form the inner ring magnetic circuit system. The voice coil 7 is arranged in the annular magnetic gap formed between the outer ring magnetic circuit system and the inner ring magnetic circuit system. The magnet assembly is connected to the fixed structure through a suspension system. After an audio current is passed through the voice coil 7, it generates an electromagnetic interaction with the magnetic field where the magnet assembly is located, thereby driving the magnet assembly to vibrate in a predetermined direction under the support and guidance of the suspension system.

[0030] To reliably support the voice coil 7, a voice coil frame 8 is connected to the voice coil 7. The voice coil frame 8 is used to stably support and position the voice coil 7, and efficiently transmit the driving force generated by the voice coil 7 to the bone conduction vibration transmission component, further improving energy transfer efficiency and structural reliability. One end of the voice coil frame 8 extends out of the annular magnetic gap formed between the outer and inner magnetic circuit systems. The voice coil 7 is wound around the outer circumference or inner circumference of the voice coil frame 8. The voice coil frame 8 can be cylindrical, annular, frame-like, or a partially load-bearing structure. The voice coil 7 can have a single or multiple winding layers, and the winding method can be single winding or multiple windings to meet different driving requirements.

[0031] The upper outer ring magnet 1, the outer ring magnetic conductor 2, the lower outer ring magnet 3, the upper inner ring magnet 4, the inner ring magnetic conductor 5, and the lower inner ring magnet 6 constitute a magnet assembly. The magnet assembly is connected to the voice coil frame 8 via a suspension system. The voice coil frame 8 is fixedly mounted on a fixed structure, and the magnet assembly is connected to the fixed structure via the suspension system.

[0032] The upper outer ring magnet 1 is correspondingly arranged with the upper inner ring magnet 4, the outer ring magnetic conductor 2 is correspondingly arranged with the inner ring magnetic conductor 5, and the lower outer ring magnet 3 is correspondingly arranged with the lower inner ring magnet 6. The outer ring magnetic conductor 2 and the inner ring magnetic conductor 5 are integral magnetic conductors, separate magnetic conductors, or magnetic conductor structures formed by combining multiple magnetic conductor components.

[0033] The number of the upper outer ring magnet 1, lower outer ring magnet 3, upper inner ring magnet 4, and lower inner ring magnet 6 are one or more. That is, the number, shape, polarity arrangement, and corresponding positional relationship of the magnets of the upper outer ring magnet 1, lower outer ring magnet 3, upper inner ring magnet 4, and lower inner ring magnet 6 can be adjusted according to the magnetic field strength, volume constraints, and performance requirements of the target product.

[0034] In this invention, the voice coil 7 is arranged in the annular magnetic gap formed between the outer and inner magnetic circuit systems. The annular magnetic gap is continuously arranged circumferentially and serves as the effective working magnetic field region of the voice coil 7. The outer magnetic guide 2 and the inner magnetic guide 5 are respectively located in the magnetic flux loops of their respective magnetic circuit systems, providing low magnetic resistance paths and guiding and converging the magnetic flux. This allows the magnetic flux generated by the outer and inner magnetic circuit systems to overlap or synergistically distribute at the annular magnetic gap, thereby increasing the magnetic flux density within the gap and improving the uniformity of the magnetic field distribution.

[0035] And, as Figure 3 and Figure 4 As shown in the COMSOL multiphysics simulation results, under the same external dimensions and magnet material parameters, the magnetic flux can achieve a more concentrated distribution in the annular magnetic gap region through the synergistic guiding effect of the inner and outer dual magnetic circuits and the magnetic conductor. The peak magnetic flux density within the annular magnetic gap can reach approximately 1T (maximum). These simulation results demonstrate that the structure of this invention can effectively increase the working magnetic field strength of the magnetic gap, enabling the voice coil 7 to obtain a greater Lorentz force output under the same current conditions, thereby improving driving efficiency and enhancing the output performance of the bone conduction loudspeaker.

[0036] During operation, when an audio current is applied to the voice coil 7, it interacts electromagnetically with the magnetic field formed by the magnet assembly, thereby generating an electromagnetic force that drives the magnet assembly to move. Under the elastic support and guidance of the suspension system, the magnet assembly vibrates mechanically in a predetermined direction, achieving bone conduction output of sound. By employing both internal and external dual magnetic circuits and the combined guidance of magnetic conductive components, this invention can increase the effective magnetic flux density and magnetic flux utilization rate at the magnetic gap within a limited space, thereby improving driving efficiency and enhancing linearity and stability during the driving process.

[0037] This invention establishes a coaxial outer and inner magnetic circuit system, which, together with the outer magnetic guide 2 and the inner magnetic guide 5, form a low-resistivity closed magnetic circuit. This allows the magnetic flux to be concentrated and effectively utilized within the annular magnetic gap region corresponding to the voice coil 7, thereby increasing the effective magnetic flux density and flux utilization rate within the magnetic gap. Compared to a single magnetic circuit structure or a simple combination of magnets and magnetic guides, this invention can enhance the working magnetic field and reduce leakage flux and ineffective flux loss within a limited structural size.

[0038] Compared to existing bone conduction loudspeakers, this invention, by employing a structure that combines a long voice coil 7 with a short magnetic gap, ensures that the voice coil 7 continuously receives a relatively stable electromagnetic driving force throughout the entire movement process, thereby improving the Lorentz force output level and ultimately enhancing the driving efficiency and output performance of the bone conduction loudspeaker.

[0039] This invention forms a superimposed or synergistic magnetic field distribution at the annular magnetic gap by the outer and inner magnetic circuit systems, which helps to improve the uniformity and stability of the magnetic field in the magnetic gap, reduce the fluctuations caused by the force change with position during the reciprocating motion of the voice coil 7, thereby improving the driving linearity and working stability, reducing distortion and improving the output consistency at different frequency bands.

[0040] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A dual-magnetic-circuit high-flux-density magnetic circuit structure for a bone conduction loudspeaker, characterized in that: It includes an upper outer ring magnet (1), an outer ring magnetic conductor (2), a lower outer ring magnet (3), an upper inner ring magnet (4), an inner ring magnetic conductor (5), a lower inner ring magnet (6), and a voice coil (7); the upper outer ring magnet (1), the outer ring magnetic conductor (2), and the lower outer ring magnet (3) form an outer ring magnetic circuit system, the upper inner ring magnet (4), the inner ring magnetic conductor (5), and the lower inner ring magnet (6) form an inner ring magnetic circuit system, and the voice coil (7) is arranged in the annular magnetic gap formed between the outer ring magnetic circuit system and the inner ring magnetic circuit system.

2. The dual-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker according to claim 1, characterized in that: The voice coil (7) is connected to a voice coil frame (8).

3. The dual-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker according to claim 2, characterized in that: One end of the voice coil skeleton (8) extends out of the annular magnetic gap formed between the outer magnetic circuit system and the inner magnetic circuit system.

4. The dual-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker according to claim 2, characterized in that: The voice coil (7) is wound around the outer periphery of the voice coil frame (8) or the inner periphery of the voice coil frame (8).

5. The dual-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker according to claim 2, characterized in that: The voice coil skeleton (8) is cylindrical in shape, and the voice coil (7) is connected to the voice coil skeleton (8) on the entire circumference.

6. The dual-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker according to claim 5, characterized in that: The voice coil (7) has a single or multiple winding layers, and the winding method of the voice coil (7) is a single winding or a multiple winding.

7. The dual-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker according to claim 2, characterized in that: The upper outer ring magnet (1), the outer ring magnetic conductor (2), the lower outer ring magnet (3), the upper inner ring magnet (4), the inner ring magnetic conductor (5), and the lower inner ring magnet (6) constitute a magnet assembly. The magnet assembly is connected to the voice coil skeleton (8) through a suspension system.

8. The dual-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker according to claim 1, characterized in that: The upper outer ring magnet (1) is correspondingly arranged with the upper inner ring magnet (4), the outer ring magnetic conductor (2) is correspondingly arranged with the inner ring magnetic conductor (5), and the lower outer ring magnet (3) is correspondingly arranged with the lower inner ring magnet (6).

9. The dual-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker according to claim 1, characterized in that: The outer ring magnetic conductor (2) and the inner ring magnetic conductor (5) are integral magnetic conductors, split magnetic conductors, or magnetic conductor structures formed by combining multiple magnetic conductor components.

10. The dual-magnetic-circuit high-flux-density magnetic circuit structure of a bone conduction loudspeaker according to claim 1, characterized in that: The number of the upper outer ring magnet (1), the lower outer ring magnet (3), the upper inner ring magnet (4), and the lower inner ring magnet (6) are one or more respectively.

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