Bone conduction loudspeaker with double-coil hollow design

Abstract

The invention discloses a double-coil bone conduction loudspeaker with a hollow design. The double-coil bone conduction loudspeaker comprises a shell (10), a first elastic sheet (5), a second elastic sheet (6), a first iron washer (8), a second iron washer (9), a magnet (7), a first coil (1), a second coil (2), an adapter plate (12), an upper shell (3) and a lower shell (4), the upper shell (3) and the lower shell (4) are arranged on the upper face and the lower face of the outer shell (10) and jointly define an inner containing space. The first coil (1) is fixedly arranged on an internal extension part of the upper shell (3), and the second coil (2) is fixedly arranged on an internal extension part of the lower shell (4). According to the invention, a fully-wrapped double-coil hollow design is adopted, the acoustic sensitivity and the high-frequency anti-howling capability are remarkably improved, and meanwhile, the compatibility of compact structure, efficient vibration conduction and automatic assembly is realized.

Description

Technical Field

[0001] The present invention relates to the field of loudspeakers, and in particular to a bone conduction loudspeaker with a double-coil hollow design. Background Art

[0002] Bone conduction speakers are a special type of acoustic device that converts electrical signals into mechanical vibrations, transmitting them directly to the auditory system through skeletal structures such as the skull, jaw, or ear bones. These speakers are widely used in hearing aids, assistive listening devices, sports headphones, and voice communication terminals. They offer advantages such as open ear canals, a non-blocking feel, and a comfortable fit, making them particularly suitable for users with hearing loss and those using them in complex environments.

[0003] like Figure 1 As shown, existing bone conduction speakers mostly use a single-coil excitation structure, where the coil is placed between the magnetic circuit formed by the magnet and the magnetic conductive sheet, and the spring drives the vibration component to move vertically. However, this traditional structure has the following technical limitations:

[0004] The single-coil structure has limited magnetic field utilization, especially low thrust output near the FO (lowest resonant frequency), resulting in unsatisfactory mid- and low-frequency performance.

[0005] To achieve sufficient vibration, traditional structures require larger magnets or travel space, which is not conducive to product miniaturization and compactness. In particular, they appear bulky in assistive listening devices or wearable devices.

[0006] Due to the imprecise control of structural resonance, traditional bone conduction speakers often have low inductive reactance in the high-frequency band, making it difficult to effectively suppress howling, affecting sound quality and user experience.

[0007] The single coil + shrapnel structure requires precise adjustment of the magnetic spacing, which makes manual assembly complex and difficult to ensure consistency and yield in mass production.

[0008] To solve the above problems, there is an urgent need for a new bone conduction speaker structure that is optimized in terms of sensitivity, compactness, anti-howling performance, assembly efficiency, etc., so as to better meet the product application needs of high-performance scenarios such as assisted listening and hearing aids. Summary of the Invention

[0009] In order to solve the above problems, the present invention provides a bone conduction speaker with a double-coil hollow design, which can effectively solve the shortcomings of the existing technology.

[0010] The present invention is achieved through the following technical solutions: a bone conduction speaker with a double-coil hollow design, comprising a first spring, a second spring, a first iron washer, a second iron washer, a magnet, a first coil, a second coil, an adapter plate, a housing, an upper housing, and a lower housing;

[0011] The upper shell and the lower shell are arranged on the upper and lower sides of the outer shell and together enclose an internal accommodating space;

[0012] The first coil is fixedly mounted on the inner extension of the upper shell, and the second coil is fixedly mounted on the inner extension of the lower shell;

[0013] The first coil and the second coil are connected in parallel and are arranged at the upper and lower parts of the accommodating space relative to each other;

[0014] The first iron washer and the second iron washer are respectively sleeved on the periphery of the first coil and the second coil, and the first iron washer and the second iron washer are arranged opposite to each other in the axial direction;

[0015] The magnet is sandwiched between the first iron washer and the second iron washer to form a closed magnetic circuit;

[0016] The first spring piece is arranged between the first iron washer and the upper shell, and the second spring piece is arranged between the second iron washer and the lower shell. The first spring piece and the second spring piece jointly support the vibration unit composed of the magnet and the iron washer, and induce magnetic field changes after the first coil and the second coil are energized, driving the vibration unit to vibrate along the axial direction.

[0017] As a preferred technical solution, the first iron washer and the second iron washer are in a ring structure.

[0018] As a preferred technical solution, the first spring piece and the second spring piece have a circular structure with a hole in the middle. They are both made of steel, spring steel, beryllium copper or special high-density steel with elastic recovery properties. Regular or irregular hollow areas are provided on the first spring piece and the second spring piece.

[0019] As a preferred technical solution, the housing is made of aluminum stretch material, plastic injection molding material, iron material or steel material.

[0020] As a preferred technical solution, the upper shell and the lower shell are respectively installed on the upper end and the lower end of the outer shell through a snap-fit structure, an adhesive connection structure or a laser welding structure.

[0021] As a preferred technical solution, the first coil and the second coil are wound with thickened and lengthened wires and connected in parallel to enhance the magnetic field force and improve the sensitivity near the FO frequency.

[0022] As a preferred technical solution, the first iron washer and the second iron washer are made of magnetic conductive material and together with the magnet form a ring magnetic circuit structure.

[0023] As a preferred technical solution, the first iron washer and the second iron washer, the first elastic sheet and the second elastic sheet, and the first coil and the second coil are symmetrically arranged in the axial direction to form a dynamically balanced vibration structure.

[0024] As a preferred technical solution, a wire hole is reserved between the first coil and the second coil for passing the wire.

[0025] As a preferred technical solution, it also includes an adapter plate, which is installed on the top of the upper shell and connected to the lead-out ends of the first coil and the second coil for realizing signal connection with an external circuit.

[0026] The beneficial effects of the present invention are as follows: the present invention adopts a parallel dual-coil structure and arranges a thickened and lengthened wire coil in the effective magnetic field gap. According to the F=BLi principle, a greater electromagnetic driving force can be obtained under the same input voltage and magnetic field conditions, effectively improving the acoustic sensitivity of the speaker near the lowest resonance frequency (FO);

[0027] The present invention uses a dual-coil configuration and a coordinated design of the magnetic circuit structure to enable the speaker to exhibit high inductive reactance characteristics in the high-frequency band, which can quickly attenuate mid- and high-frequency energy, significantly reducing the howling phenomenon caused by mid- and high-frequency feedback in hearing-aid or auxiliary hearing applications, and improving the stability of sound quality.

[0028] The present invention adopts a fully enclosed hollow structure layout, with the coil placed at the extended end of the shell and surrounded by a magnetic conductive sheet. The overall structure is compact, effectively saving internal space of the device, and providing greater design freedom and higher integration for finished products such as audio terminals, wearable devices, and hearing aids.

[0029] The bone conduction speaker of the present invention has a clear modular design of its components. The magnetic circuit unit, coil unit, and housing are assembled in layers in the axial direction, which facilitates standardized and rapid assembly on an automated production line, reduces the difficulty of manual work, and significantly improves product consistency and qualification rate.

[0030] The present invention uses a built-in vibration unit to excite the entire housing to vibrate, so that when the speaker is attached to the surface of human bones (such as the auditory bones, skull or teeth), sound waves can be efficiently transmitted to the auditory system in the form of mechanical vibrations, enhancing the bone conduction listening experience;

[0031] The present invention adopts a fully enclosed double-coil hollow design with the characteristics of high inductance and low distortion. Due to the high inductance, the 200HZ-2000HZ value in the SPL curve is particularly obvious. The curve will be more than 5bB higher, forming a convex peak. The 200HZ-2000HZ value in the SPL curve is an important frequency band that reflects the degree of vocal restoration. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 An internal cross-sectional view of a speaker in the prior art;

[0034] Figure 2 This is a schematic internal cross-sectional view of Example 1 of the present invention;

[0035] Figure 3 This is an explosion diagram of Example 1 of the present invention;

[0036] Figure 4 It is a schematic structural diagram of the shrapnel of the present invention;

[0037] Figure 5 This is a schematic internal cross-sectional view of Example 2 of the present invention;

[0038] Figure 6 This is a schematic diagram of the internal structure of Example 3 of the present invention;

[0039] Description of reference numerals:

[0040] 10. Outer shell; 3. Upper shell; 4. Lower shell; 1. First coil; 2. Second coil; 8. First iron washer; 9. Second iron washer; 7. Magnet; 5. First spring; 6. Second spring; 12. Adapter plate; 13. Wire hole; 71. First magnet; 72. Second magnet; 14. Third iron washer. DETAILED DESCRIPTION

[0041] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0042] Any feature disclosed in this specification (including any appended claims, abstract and drawings), unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0043] Example 1

[0044] like Figure 2-Figure 4As shown, the present invention provides a bone conduction speaker with a double-coil hollow design. In a specific implementation, its structure includes a housing 10, a first spring 5, a second spring 6, a first iron washer 8, a second iron washer 9, a magnet 7, a first coil 1, a second coil 2, an adapter plate 12, an upper housing 3 and a lower housing 4;

[0045] The shell 10 serves as the main supporting structure of the bone conduction speaker. Its appearance can be adapted and designed according to the shell shape of the product to be used. The upper and lower ends of the shell 10 are respectively provided with an upper shell 3 and a lower shell 4. The upper shell 3 and the lower shell 4 are respectively fixed to the top and bottom of the shell 10 by means of snaps, screws or ultrasonic welding, and together with the shell 10 form an overall enclosed internal accommodating space.

[0046] In the accommodation space, the first coil 1 is fixedly mounted on the inner extension of the upper shell 3, and the second coil 2 is fixedly mounted on the inner extension of the lower shell 4;

[0047] The first coil 1 and the second coil 2 are arranged in mirror symmetry in structure and are connected in parallel in circuit connection. The two are located in the upper and lower parts of the accommodation space respectively.

[0048] In order to obtain stronger driving force and higher electroacoustic conversion efficiency, the first coil 1 and the second coil 2 are both wound with thicker and longer wires, so that under the same driving voltage, a stronger Lorentz force can be generated by a larger current, thereby improving the magneto-induced vibration efficiency.

[0049] Surrounding the first coil 1 and the second coil 2 are first and second iron washers 8 and 9, respectively. Both are annular and made of materials with good magnetic conductivity, such as iron or mild steel. These annular magnetic sheets, tightly fitted around the first and second coils 1 and 2, not only help create a stable annular magnetic circuit but also effectively control the direction of the magnetic flux, improving the circuit's tightness and thus enhancing the efficiency of electromagnetic energy utilization.

[0050] The magnet 7 is sandwiched between the first iron washer 8 and the second iron washer 9, located in the center of the two magnetic conductive sheets, forming an efficient magnetic field path by closing the magnetic flux, so that a stable and concentrated effective magnetic field gap is formed in the center of the structure for the coil to act.

[0051] A first spring clip 5 is disposed between the first iron washer 8 and the upper shell 3, and a second spring clip 6 is disposed between the second iron washer 9 and the lower shell 4. Both the first spring clip 5 and the second spring clip 6 are circular in structure with a central opening to reduce mass and provide flexible support. They can be made of steel, spring steel, beryllium copper, or special high-density steel, exhibiting excellent elastic recovery properties and fatigue resistance over long periods of use.

[0052] In order to further regulate the elastic modulus and resonant frequency, regular or irregular hollow areas can be designed on the two spring pieces to optimize their dynamic response capabilities while meeting the structural support strength.

[0053] The function of the spring is not only to provide support, but more importantly, it serves as the bearing structure of the entire magnetic circuit assembly, that is, the magnetic unit composed of the magnet 7 and the iron washer.

[0054] After the coil is energized, the current forms an electromagnetic force under the action of the magnetic field, driving the magnetic unit to perform reciprocating micro-vibrations along the axial direction, that is, from top to bottom or from bottom to top; the vibration is directly transmitted to the bones, such as the skull, teeth or ear bones, through the outer shell 10 or the connection parts with the device casing, so that the sound waves are transmitted to the auditory nervous system in the form of mechanical vibrations through bone conduction, thereby realizing the hearing function.

[0055] A reserved wire hole 13 is provided between the first coil 1 and the second coil 2. This hole 13, located in a fixed portion of the housing or near the adapter plate 12, allows for the coil lead wires or signal cables to pass through. This facilitates electrical connection while ensuring the compactness and integrity of the overall structure. This hole 13 can be injected with glue and sealed during production to prevent dust and moisture from entering the bone conduction speaker.

[0056] To connect to external audio equipment, the bone conduction speaker is also equipped with an adapter board 12. The adapter board 12 is made of a printed circuit board PCB or a flexible circuit board FPC, mounted on the top of the upper shell 3, and connected to the lead terminals of the first coil 1 and the second coil 2 by welding or connectors.

[0057] The adapter board 12 serves as a bridge between the speaker and the external system, and can reliably transmit control signals, audio signals, etc. to the inside of the coils 1 and 2. It also facilitates the integration of amplifier circuits, filtering modules or microcontroller chips to achieve functional expansion such as intelligent control, audio adjustment or status recognition.

[0058] The speaker has a symmetrical and compact structure, and its components are assembled in layers axially, facilitating modular mass production on standardized production lines.

[0059] The highly versatile materials of each component allow for flexible material selection, meeting multiple requirements for magnetic shielding, magnetic conductivity, elasticity, and heat dissipation while reducing manufacturing costs. This speaker structure is not only suitable for use in hearing aids, hearing aids, and voice communication equipment, but also allows for size adjustments and housing modifications to suit different applications, enabling diverse product designs. It has excellent practicality and market prospects.

[0060] Example 2

[0061] like Figure 5As shown, based on Example 1, Example 2 provides a bone conduction speaker with another structural form, whose overall structure and component layout are basically the same as those of Example 1, including components such as the outer shell 10, the upper shell 3, the lower shell 4, the first spring 5, the second spring 6, the first iron washer 8, the second iron washer 9, the magnet 7 and the adapter plate 12, and the connection relationship and functional settings of the relevant components remain unchanged.

[0062] Compared to Example 1, Example 2 differs in that the outer surfaces of the upper shell 3 and lower shell 4 are flush, meaning that their upper and lower surfaces, where they mate with the outer shell 10, lack recessed areas. Compared to Example 1, which included a recessed area on the outer shell, Example 2 eliminates this recess, resulting in a more streamlined overall structure and a slight increase in the shell's width. The increased thickness of the outer shell 10 provides a larger contact surface at the assembly or user end, making it suitable for product designs requiring high requirements for form integrity, fit area, or structural strength.

[0063] This structural form provides diversity in appearance design and assembly methods without changing the core vibration unit and its working principle inside the bone conduction speaker, facilitating the development of multi-size and multi-style product series, and enhancing the product's scalability and engineering application flexibility.

[0064] Example 3

[0065] like Figure 6 As shown, based on Example 1, Example 3 provides a variant of a bone conduction speaker using a dual-magnet structure. This example is consistent with Example 1 in terms of overall structural configuration, component connection relationships, and vibration principle. It still includes components such as the housing 10, upper housing 3, lower housing 4, first coil 1, second coil 2, first iron washer 8, second iron washer 9, first spring 5, second spring 6, and adapter plate 12. The functions and layout of these components remain unchanged.

[0066] The main difference from Example 1 is that in Example 3, the magnet used to generate the magnetic field is replaced by two magnets, namely a first magnet 71 and a second magnet 72, with a third iron washer 14 positioned between them for magnetic flux guidance. Specifically, the first magnet 71 is positioned between the first iron washer 8 and the third iron washer 14, while the second magnet 72 is positioned between the second iron washer 9 and the third iron washer 14. The first magnet 71 and the second magnet 72 are magnetized in opposite directions and arranged axially symmetrically. The third iron washer 14 forms a central isolation and magnetic flux merging node, thereby creating a composite magnetic field structure with dual magnetic sources and a single closed magnetic circuit.

[0067] This dual-magnet setup, through the combined effect of two opposing magnetic sources, enhances the magnetic flux density on both sides of the magnetic circuit without significantly increasing the thickness of the individual magnets. This increases the magnetic flux strength in the effective magnetic field gap, further improving the bone conduction speaker's response efficiency and vibration thrust near the FO frequency. Furthermore, the placement of the third iron washer 14 helps guide the magnetic flux path, suppressing magnetic circuit leakage, improving magnetic field concentration and symmetry, and enhancing the overall dynamic balance of the structure.

[0068] Except for the changes in the number and arrangement of magnets, the rest of the structural design, spring-loaded bearing method, coil excitation method and installation connection method in Example 3 are the same as those in Example 1, and can be adapted to hearing aids, hearing assistance or head-mounted bone conduction products that have higher requirements for driving force output and magnetic field uniformity.

[0069] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that are not conceived through creative work should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined in the claims.

Claims

1. A bone conduction speaker with a double-coil hollow design, characterized in that: It comprises a housing (10), a first spring piece (5), a second spring piece (6), a first iron washer (8), a second iron washer (9), a magnet (7), a first coil (1), a second coil (2), an adapter plate (12), an upper housing (3) and a lower housing (4); The upper shell (3) and the lower shell (4) are arranged on the upper and lower surfaces of the outer shell (10) and together enclose an internal accommodating space; The first coil (1) is fixedly mounted on an inner extension of the upper shell (3), and the second coil (2) is fixedly mounted on an inner extension of the lower shell (4); The first coil (1) and the second coil (2) are connected in parallel and are arranged relatively at the upper and lower parts of the accommodating space; The first iron washer (8) and the second iron washer (9) are respectively sleeved on the periphery of the first coil (1) and the second coil (2), and the first iron washer (8) and the second iron washer (9) are arranged opposite to each other in the axial direction; The magnet (7) is sandwiched between the first iron washer (8) and the second iron washer (9) to form a closed magnetic circuit; The first spring piece (5) is arranged between the first iron washer (8) and the upper shell (3), and the second spring piece (6) is arranged between the second iron washer (9) and the lower shell (4). The first spring piece (5) and the second spring piece (6) jointly support a vibration unit composed of a magnet (7) and the iron washer, and induce a change in the magnetic field after the first coil (1) and the second coil (2) are energized, thereby driving the vibration unit to vibrate in the axial direction.

2. The bone conduction speaker with a double-coil hollow design according to claim 1, characterized in that: The first iron washer (8) and the second iron washer (9) are in a ring structure.

3. The bone conduction speaker with a double-coil hollow design according to claim 1, characterized in that: The first spring piece (5) and the second spring piece (6) are circular in structure with a hole in the middle. They are both made of steel, spring steel, beryllium copper or special high-density steel with elastic recovery properties. Regular or irregular hollow areas are provided on the first spring piece (5) and the second spring piece (6).

4. The bone conduction speaker with a double-coil hollow design according to claim 1, characterized in that: The housing (10) is made of aluminum stretch material, plastic injection molding material, iron material or steel material.

5. The bone conduction speaker with a double-coil hollow design according to claim 1, characterized in that: The upper shell (3) and the lower shell (4) are respectively mounted on the upper end and the lower end of the outer shell (10) via a snap-fit structure, an adhesive connection structure or a laser welding structure.

6. The bone conduction speaker with a double-coil hollow design according to claim 1, characterized in that: The first coil (1) and the second coil (2) are wound with thickened and lengthened wires and are connected in parallel to enhance the magnetic field force and improve the sensitivity near the FO frequency.

7. The bone conduction speaker with a double-coil hollow design according to claim 1, characterized in that: The first iron washer (8) and the second iron washer (9) are made of magnetic conductive material and together with the magnet (7) form an annular magnetic circuit structure.

8. The bone conduction speaker with a double-coil hollow design according to claim 1, characterized in that: The first iron washer (8) and the second iron washer (9), the first spring piece (5) and the second spring piece (6), and the first coil (1) and the second coil (2) are symmetrically arranged in the axial direction to form a dynamically balanced vibration structure.

9. The bone conduction speaker with a double-coil hollow design according to claim 1, characterized in that: A wire hole (13) is reserved between the first coil (1) and the second coil (2) for passing a wire.

10. The bone conduction speaker with a double-coil hollow design according to claim 1, characterized in that: It also includes an adapter plate (12), which is installed on the top of the upper shell (3) and connected to the lead-out ends of the first coil (1) and the second coil (2) to achieve signal connection with an external circuit.

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