Sleeve type sound amplification structure and loudspeaker

Abstract

The invention discloses a sleeve type sound amplification structure and a loudspeaker, the sleeve type sound amplification structure comprises a sound production unit and a magnetic circuit unit, the magnetic circuit unit comprises a central magnet and a plurality of groups of edge magnetic structures, the central magnet is rectangular, the plurality of groups of edge magnetic structures are nested layer by layer from inside to outside by taking the central magnet as a center, and the edge magnetic structures are arranged in the central magnet. The edge magnet structure comprises four edge magnets which are respectively matched with four edges of the central magnet; the sound production unit comprises a vibrating diaphragm and a plurality of voice coils, the plurality of groups of edge magnetic structures are nested layer by layer by taking the central magnet as a center, magnetic gaps for accommodating the voice coils are formed at intervals, and the plurality of voice coils are bonded with the vibrating diaphragm; the voice coil is used for driving the vibrating diaphragm to produce sound; therefore, the relatively effective length of the voice coil in the magnetic field is increased by segmenting the larger voice coil, and meanwhile, the magnetic field is superposed after segmentation, so that the strength and the utilization rate of the voice coil can be further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of speakers, and in particular, to a sleeve - type sound amplification structure and a speaker. Background Art

[0002] A speaker is an electro - acoustic transducer. The speakers used in various electronic products such as mobile phones and tablet computers are thin - shaped products. Its basic structure includes a vibration part, a magnetic circuit part, and a structure part. The vibration part mainly includes a diaphragm and a voice coil. The diaphragm and the voice coil are connected. After an alternating current is applied, the voice coil moves in the magnetic field and drives the diaphragm to vibrate. In this way, the electrical signal is converted into a mechanical vibration signal. The magnetic circuit part mainly includes a permanent magnet, which provides a stable magnetic field for the vibration part. The structure part is used to install the vibration part and the magnetic circuit part, including a chassis for support, a surround located around the diaphragm to provide elastic support to ensure the movement of the diaphragm, and a dust cap to prevent dust from entering the voice coil and the magnetic circuit system, etc. Thus, its principle is that when an audio current passes through the voice coil, the voice coil is affected by the electromagnetic force in the magnetic field and generates an alternating motion. This motion drives the diaphragm to vibrate, and the vibration of the diaphragm pushes the air to generate sound waves, which are finally perceived as sound by the human ear. Limited by the limited space and shape of the thin plate, it is difficult to increase the sound volume of the speaker in electronic products, and the upper limit of its sound improvement is relatively low. Summary of the Invention

[0003] In order to overcome the defects of the prior art, the technical problem to be solved by the present invention is to provide a sleeve - type sound amplification structure and a speaker, which can effectively increase the upper limit of the sound volume of the speaker by increasing the relative length of the voice coil and the magnetic field strength in a limited space.

[0004] To achieve this purpose, the present invention adopts the following technical solutions:

[0005] A sleeve - type sound amplification structure provided by the present invention includes a sound - generating unit and a magnetic - circuit unit. The magnetic - circuit unit includes a central magnet and several groups of side - magnetic structures. The central magnet is rectangular, and several groups of the side - magnetic structures are nested layer by layer from the inside to the outside with the central magnet as the center. The side - magnetic structure includes four side magnets that respectively cooperate with the four sides of the central magnet. The sound - generating unit includes a diaphragm and several voice coils. There are magnetic gaps for accommodating the voice coils between several groups of the side - magnetic structures nested layer by layer with the central magnet as the center. Several voice coils are bonded to the diaphragm. Thus, the voice coils drive the diaphragm to generate sound. Several voice coils are respectively arranged in the corresponding magnetic gaps, and the voice coils and the central magnet are concentrically arranged. In this way, by dividing a larger voice coil, the relative effective length of the voice coil in the magnetic field is increased, and at the same time, the magnetic fields are superimposed after division, and its intensity and utilization rate can be further improved.

[0006] Such as Figure 1As shown, during the design process, in order to quantify the standard for improving the sound of the speaker, let the sound of the speaker be Q, then the sound Q can be expressed as:

[0007]

[0008] Among them, G is the comprehensive index; r i is the width of the i-th magnetic gap from the center magnet outwards; x is the total number of side magnetic structures and voice coils set, and L i refers to the effective length of the i-th voice coil; D i is the length of the i-th side magnetic structure from the center magnet outwards, and d i is the width of the i-th side magnetic structure from the center magnet outwards.

[0009] Meanwhile, to avoid sound distortion and ensure structural stability, the following constraint conditions need to be satisfied:

[0010] S10: Distortion constraint, satisfying:

[0011]

[0012] C is the distortion critical parameter;

[0013] S20: Feasibility constraint, satisfying:

[0014] S21: Geometric nesting constraint, when the intersecting sides of the center magnet are equal, that is, when the center magnet is square, let its side length be T 1 , the recurrence relation of the length of each layer of side magnetic structure is:

[0015]

[0016] And when i = 0, D 1 = T 1 ;

[0017] If the intersecting sides of the center magnet are not equal, similarly, the recurrence is carried out according to the above formula;

[0018] S22: To prevent mechanical interference between the voice coil and the magnet during vibration, the cross-sectional width of the i-th voice coil from the center magnet outwards is y i , then:

[0019] y i ≤λr i (0 < λ < 1)

[0020] S23: To ensure structural stability, the displacement of the voice coil during vibration does not exceed the safe range of the magnetic gap:

[0021]

[0022] Among them, a is the diaphragm stiffness and β is the safety factor.

[0023] A loudspeaker includes a diaphragm, and the above-mentioned sleeve-type sound amplification structure is arranged in the diaphragm; to efficiently improve the upper limit of the sound improvement of the loudspeaker.

[0024] The beneficial effects of the present invention are as follows:

[0025] In the present invention, the voice coil is designed in a sleeve type under the limitation of shape and space. By increasing the relative length of the voice coil in the magnetic field and the intensity of the magnetic field where the voice coil is located, the electromagnetic force received by the voice coil in the magnetic field is increased, so that the voice coil can have a larger amplitude when driving the diaphragm to vibrate, thereby improving the sound of the loudspeaker. At the same time, by establishing a design calculation model based on the above structure, the optimal sound improvement design under different requirements can be optimized and assisted to avoid the distortion of the sound quality of the loudspeaker. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the principle annotation of a sleeve-type sound amplification structure provided in the specific embodiment of the present invention;

[0027] Figure 2 It is a schematic diagram of the principle of a sleeve-type sound amplification structure provided in the specific embodiment of the present invention

[0028] In the figure:

[0029] 1, sound generating unit; 2, magnetic circuit unit;

[0030] 21, central magnet; 22, edge magnetic structure; 221, edge magnet; 23, magnetic gap;

[0031] 11, diaphragm; 12, voice coil. Specific Embodiments

[0032] The technical solution of the present invention will be further described below in conjunction with the drawings and through specific embodiments.

[0033] The sound volume emitted by the loudspeaker depends on the electromagnetic force acting on the voice coil 12 in the magnetic field, that is, when the received electromagnetic force is large, the amplitude of the voice coil 12 driving the diaphragm 11 will be larger, so that the loudspeaker can emit a louder sound. When the received electromagnetic force is small, the amplitude of the voice coil 12 driving the diaphragm 11 will be smaller, and at this time the sound emitted by the loudspeaker is smaller; the electromagnetic force received by the voice coil 12 in the magnetic field can be expressed by the following formula:

[0034] F = B · I · L

[0035] Among them, F represents the electromagnetic force received by the voice coil 12 in the magnetic field; B represents the intensity of the magnetic field; I represents the current passing through the voice coil 12; L represents the length of the voice coil 12;

[0036] As can be seen from the above formula, the magnitude of the force is proportional to the current, the magnetic field strength, and the length of the voice coil 12. When the current is used as the signal input, the electromagnetic force on the voice coil 12 in the magnetic field can be increased by increasing the magnetic field strength and the length of the voice coil 12, so as to achieve the purpose of increasing the sound of the speaker; that is, let the sound of the speaker be Q, then:

[0037] Q ∝ F

[0038] Based on the above principle, as Figure 1 shown, a sleeve-type sound amplification structure is proposed, which mainly includes a sound generating unit 1 and a magnetic circuit unit 2. The magnetic circuit unit 2 includes a central magnet 21 and several groups of side magnetic structures 22. The central magnet 21 is rectangular, and several groups of side magnetic structures 22 are nested layer by layer from the inside to the outside with the central magnet 21 as the center. The side magnetic structure 22 includes four side magnets 221 that cooperate with the four sides of the central magnet 21 respectively;

[0039] The sound generating unit 1 includes a diaphragm 11 and several voice coils 12. There are magnetic gaps 23 for accommodating the voice coils 12 between several groups of side magnetic structures 22 nested layer by layer with the central magnet 21 as the center. Several voice coils 12 are respectively arranged in the corresponding magnetic gaps 23, and the voice coils 12 are concentric with the central magnet 21; several voice coils 12 are bonded to the diaphragm 11; thus, the voice coils 12 are used to drive the diaphragm 11 to generate sound; the four corners of the central magnet 21 and the voice coils 12 adopt rounded corners for easy assembly and to prevent stress concentration, and the diaphragm 11 adopts a polymer composite film material TPEE middle film or metal film with a foam sandwich structure to ensure the sound quality of the speaker;

[0040] In this way, through the structure of multiple side magnetic structures 22 and the nested layers of multiple voice coils 12, which is similar to a sleeve-type structure, at the same time, the central magnet 21 and several groups of side magnetic structures 22 form a multi-layer inner magnetic structure, and the central magnet 21 and the side magnets 221 are permanent magnets; this not only increases the intensity of the voice coil 12 in the magnetic field by using multiple groups of magnets, but also makes the magnetic field more stable, reduces magnetic leakage, and at the same time increases the effective length of the voice coil 12 in the magnetic field, so that the force on the multiple voice coils 12 in the magnetic field is greater. When they jointly drive the diaphragm 11 to vibrate and generate sound, a larger amplitude can be obtained, thereby improving the upper limit of the sound generation of the speaker,

[0041] Preferably, several voice coils 12 are connected to each other through a circuit, and the voice coils 12 are connected to the external circuit through FPC to ensure the lossless transmission of the audio signal;

[0042] Several voice coils 12 are connected in series. At this time, let the total electromagnetic force received by several voice coils 12 be F t , then:

[0043] Q ∝ F t

[0044] Then the electromagnetic force F on the i-th voice coil 12 is i For: F i =B i ·L i I;

[0045] Among them, L i It refers to the effective length of the i-th voice coil 12 from the center magnet 21. Let the width of the i-th magnetic gap 23 from the center magnet 21 to the outside be r i , the length of the side magnet 221 in the i-th side magnet structure 22 from the center magnet 21 is D i , the width of the side magnet 221 in the i-th side magnet structure 22 from the center magnet 21 is d i ,but k is the proportionality coefficient;

[0046] When the number of voice coils 12 is x:

[0047] where F t is the resultant force of the electromagnetic forces on the x voice coils 12;

[0048] In summary: The sound of the speaker is Q is:

[0049]

[0050] Wherein, η is the electroacoustic conversion efficiency, and I is the current in the voice coil 12;

[0051] Let G = η·I·k, we get:

[0052]

[0053] Among them, G is the comprehensive coefficient;

[0054] According to the above function model, on the basis of the above sound amplification structure, the adjustment strategy for maximizing the sound Q is:

[0055] (1) Increase the number of voice coils 12 to x within the allowable range of space and mass, so as to maximize the total effective length of the voice coil 12 in the magnetic field.

[0056] (2) increasing the magnetic field strength of the voice coil 12, that is, increasing the length and width of the side magnetic blocks or reducing the width r of the magnetic gap 23;

[0057] Preferably, when improving the sound through the above strategy, the following constraints need to be met:

[0058] To avoid sound quality distortion, the F t In the linear range, that is:

[0059]

[0060] Among them, C is the distortion critical parameter;

[0061] Meanwhile, the influence in the physical space also needs to be considered, mainly including the following three aspects:

[0062] (1) Geometric nesting constraint. When the intersecting sides of the central magnet 21 are equal, that is, when the central magnet 21 is square, let its side length be T 1 , and the length recurrence relation of each layer of side magnetic structure 22 is:

[0063]

[0064] And when i = 0, D 1 = T 1 ;

[0065] If the intersecting sides of the central magnet 21 are not equal, the recurrence is carried out according to the above formula in the same way;

[0066] (2) To prevent mechanical interference between the voice coil 12 and the magnet during vibration, the cross-sectional width of the i-th voice coil 12 from the central magnet 21 is y i , then:

[0067] y i ≤λr i (0 < λ < 1)

[0068] (3) To ensure structural stability, the displacement of the voice coil 12 during vibration does not exceed the safe range of the magnetic gap 23:

[0069]

[0070] Among them, a is the stiffness of the diaphragm 11, and β is the safety factor.

[0071] The present invention is described through preferred embodiments. Those skilled in the art know that without departing from the spirit and scope of the present invention, various changes or equivalent replacements can be made to these features and embodiments. The present invention is not limited by the specific embodiments disclosed herein, and other embodiments falling within the scope of the claims of this application belong to the scope of protection of the present invention.

Claims

1. A sleeve-type sound amplification structure, characterized in that: The invention comprises a sound-generating unit (1) and a magnetic circuit unit (2), wherein the magnetic circuit unit (2) comprises a central magnet (21) and a plurality of sets of side magnetic structures (22), wherein the central magnet (21) is rectangular, and the plurality of sets of side magnetic structures (22) are nested layer by layer from the inside to the outside with the central magnet (21) as the center, and the side magnetic structures (22) comprise four side magnets (221) respectively cooperating with the four sides of the central magnet (21); The sound-emitting unit (1) comprises a diaphragm (11) and a plurality of voice coils (12); a plurality of groups of side magnetic structures (22) are nested layer by layer with the central magnet (21) as the center and separated by magnetic gaps (23) for accommodating the voice coils (12); the plurality of voice coils (12) are respectively arranged in corresponding magnetic gaps (23); the voice coils (12) and the central magnet (21) are concentrically arranged; and the plurality of voice coils (12) are bonded to the diaphragm (11).

2. A sleeve-type sound amplification structure according to claim 1, characterized in that: A plurality of the voice coils (12) are interconnected via a circuit, and the voice coil (12) is connected to an external circuit via an FPC to ensure lossless transmission of audio signals.

3. A sleeve-type sound amplification structure according to claim 2, characterized in that: A plurality of voice coils (12) are connected in series.

4. The sleeve-type sound amplification structure according to claim 1, characterized in that: The four corners of the central magnet (21) and the voice coil (12) are rounded transitionally arranged.

5. The sleeve-type sound amplification structure according to claim 1, characterized in that: The central magnet (21) and a plurality of groups of the side magnet structures (22) form a multi-layer internal magnet structure, and the central magnet (21) and the side magnets (221) are permanent magnets.

6. The sleeve-type sound amplification structure according to claim 1, characterized in that: The diaphragm (11) is made of a polymer composite film material TPEE with a foamed sandwich structure or a metal film.

7. The sleeve-type sound amplifying structure according to claim 6, characterized in that: Assume the sound of the speaker is Q, then the sound Q can be expressed as: Among them, G is the comprehensive index; r i is the width of the i-th magnetic gap (23) from the center magnet (21) to the outside; x is the total number of the side magnetic structures (22) and the voice coils (12) provided, L i refers to the effective length of the ith voice coil (12); D i is the length of the i-th side magnetic structure (22) from the central magnet (21), d i is the width of the i-th side magnetic structure (22) outward from the central magnet (21).

8. The sleeve-type sound amplifying structure according to claim 7, characterized in that: To avoid sound distortion and structural stability, the following constraints need to be met: S10: Distortion constraint, satisfying: C is the distortion critical parameter; S20: Feasibility constraints, satisfying: S21: Geometric nesting constraint. When the intersecting sides of the central magnet (21) are equal, that is, when the central magnet (21) is a square, assuming that its side length is T1, the recursive relationship of the length of each layer of the side magnetic structure (22) is: And when i=0, D1=T1; If the intersecting sides of the central magnet (21) are not equal, the above formula is used for recursion in the same way; S22: In order to prevent the voice coil (12) from mechanically interfering with the magnet during vibration, the cross-sectional width of the i-th voice coil (12) from the central magnet (21) to the outside is y i ,but: y i ≤λr i (0<λ<1) S23: To ensure structural stability, the displacement of the voice coil (12) during vibration does not exceed the safe range of the magnetic gap (23): Wherein, a is the stiffness of the diaphragm (11), and β is the safety factor.

9. A loudspeaker, characterized in that: It comprises a sound basin, in which a sleeve-type sound amplification structure as claimed in any one of claims 1 to 8 is arranged.

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