Magnetic circuit device for loudspeaker and loudspeaker

Abstract

This invention discloses a magnetic circuit device for loudspeakers and a loudspeaker. The magnetic circuit device for loudspeakers includes a magnet, pole pieces, a T-iron, and a voice coil. The pole pieces are disposed on one side of the magnet; the T-iron includes a base and a central post, with the base located on the other side of the magnet, and the central post passing through the magnet and the pole pieces; the side of the magnet facing the pole pieces, the pole pieces, the central post, the base, and the side of the magnet facing the base form a closed magnetic path. A thinning section is provided in the path of the magnetic path to form a magnetic saturation region, and the equivalent relative permeability of the magnetic saturation region is less than 500. Therefore, this magnetic circuit device for loudspeakers only needs to set a thinning section in the path of the magnetic path to form a magnetic saturation region, which can effectively improve the frequency response and distortion of the loudspeaker and improve the sound quality. The setting of the thinning section only needs to be completed in the original process, without adding other processes or additional auxiliary materials, so that the overall manufacturing cost of the magnetic circuit device for loudspeakers in mass production will not be increased.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of sound-generating devices, and more particularly to magnetic circuit devices for loudspeakers and loudspeakers. Background Technology

[0002] In a loudspeaker, when the voice coil vibrates in the negative direction, it will shift significantly towards the central T-iron. The high permeability of the T-iron will greatly concentrate the alternating magnetic flux around the voice coil, directly causing the voice coil inductance to change drastically and nonlinearly with the vibration displacement, affecting the frequency response of the loudspeaker and also causing harmonic distortion.

[0003] In existing technologies, an aluminum short-circuit ring is added next to the magnetic circuit gap of the speaker. The eddy current effect of the short-circuit ring is used to counteract part of the alternating magnetic flux generated by the voice coil, thereby reducing the nonlinear fluctuation of the voice coil inductance with displacement. This solution has been verified over a long period of time and can achieve a relatively stable inductance suppression effect in conventionally sized speakers.

[0004] However, the application of this type of aluminum short-circuit ring not only requires the addition of several exclusive processes such as short-circuit ring positioning, glue fixing, and insulation testing to the original magnetic circuit assembly process, which lengthens the overall production cycle, but also increases the material cost of aluminum materials and supporting auxiliary materials. Especially in the production scenario of mass consumer speakers, it will significantly increase the overall manufacturing cost. Summary of the Invention

[0005] The purpose of this invention is to provide a magnetic circuit device and a loudspeaker, solving the problem that the existing technology of setting up short-circuit rings and other structures in loudspeakers leads to a lengthened overall production process and increases the cost of materials such as aluminum, which significantly increases manufacturing costs in the mass production of loudspeakers.

[0006] To achieve this objective, the embodiments of the present invention adopt the following technical solutions: In a first aspect, embodiments of the present invention provide a magnetic circuit device for a loudspeaker, comprising: magnet; An electrode is disposed on one side of the magnet and is attached to one side of the magnet. The T-iron includes a base and a central column. The base is located on the other side of the magnet and is in contact with the other side of the magnet. The central column passes through the magnet and the pole piece, and the central column and the pole piece are spaced apart. The voice coil is inserted between the pole piece and the center post; The magnet, the side facing the pole piece, the pole piece, the central column, the base, and the side facing the base form a closed magnetic path. A thinning section is provided in the path of the magnetic path to form a magnetic saturation region. The equivalent relative permeability of the magnetic saturation region is less than 500.

[0007] Optionally, the central column has a plurality of convex teeth spaced apart around the central column in a circumferential direction, the convex teeth forming the magnetic saturation region.

[0008] Optionally, the spacing between two adjacent protrusions increases first and then decreases along the axis of the central column towards the base.

[0009] Optionally, the base includes a chassis, a side ring disposed on the edge of the chassis, and a bottom ring connected to the side ring. The bottom ring abuts against the bottom wall of the magnet. The central column is disposed on the side of the chassis facing the magnet. A thinning groove is provided on the inner or outer side of the side ring so that the chassis forms the magnetic saturation region.

[0010] Optionally, a thinning hole is formed inward on the side of the central column away from the base. The depth of the thinning hole is greater than half the height of the central column, and the diameter of the thinning hole is greater than the radius of the central column, so that the sidewall of the central column forms the magnetic saturation region.

[0011] Optionally, the thinning hole includes a vertical section and a curved section distributed along the central column axis toward the base. The diameter of the vertical section remains constant, while the diameter of the curved section decreases along the central column axis toward the base so that the wall thickness gradually increases.

[0012] Optionally, a thinning annular groove is formed on the side of the electrode away from the magnet and near the central post to form the magnetic saturation region.

[0013] Optionally, the sidewall of the thinning annular groove near the central column is inclined, and the inclination angle is less than 45°.

[0014] Optionally, a metal cap is fitted onto the end of the central column away from the base.

[0015] In a second aspect, embodiments of the present invention provide a loudspeaker, which includes: frame; The magnetic circuit device for a loudspeaker as described in any one of the first aspects is disposed in the frame.

[0016] In this embodiment of the invention, the magnetic field lines generated by the magnet travel along a closed magnetic path, originating from the side of the magnet facing the pole piece, passing through the pole piece, voice coil, center post, and base, before returning to the side of the magnet facing the base. The voice coil is located within the magnetic field between the pole piece and the center post. When an alternating current that varies with the audio signal is applied, the voice coil experiences an Ampere force that changes synchronously in direction and magnitude, thereby generating reciprocating vibrations. This achieves the conversion of electrical signals into mechanical vibrations, ultimately driving the diaphragm to push the air and produce sound. The magnetic path is thinned to form a magnetic saturation region, and the equivalent relative permeability within this region is less than 500, creating a high magnetic reluctance barrier near the voice coil. This significantly reduces the total amount of alternating magnetic flux, resulting in a substantial decrease in inductance. With reduced inductance, the high-frequency radiated sound power of the speaker does not rapidly attenuate as the frequency increases, improving high-frequency extension and effectively enhancing the speaker's frequency response. Furthermore, the formation of the magnetic saturation region allows the voice coil inductance to remain relatively stable, preventing current distortion caused by sudden changes in inductance during large voice coil displacements. It also reduces harmonic distortion, thereby improving sound quality. Therefore, the magnetic circuit device for this loudspeaker only requires a thinning section within the magnetic path to create the magnetic saturation region, effectively improving the loudspeaker's frequency response and distortion, and enhancing sound quality. The thinning section can be added within the existing process, without requiring additional steps, extending the production cycle, or adding extra auxiliary materials. This ensures that the overall manufacturing cost of mass-producing loudspeaker magnetic circuit devices remains unchanged. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the magnetic circuit device for a loudspeaker in Embodiment 1 of the present invention; Figure 2 This is a structural cross-sectional view of the magnetic circuit device for a loudspeaker in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the structure of the central column of the magnetic circuit device for a loudspeaker in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the simulated magnetic saturation region of the magnetic circuit device for a loudspeaker in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram illustrating the improved frequency response of the magnetic circuit device for a loudspeaker in Embodiment 1 of the present invention compared to a conventional structure; Figure 6 This is a schematic diagram illustrating the improvement in harmonic distortion of the magnetic circuit device for loudspeakers in Embodiment 1 of the present invention compared to a conventional structure; Figure 7 This is a table comparing the weight of the magnetic circuit device for a loudspeaker in Embodiment 1 of the present invention with that of a conventional structure and the highest temperature of the voice coil. Figure 8 This is a schematic diagram of the magnetic circuit device for a loudspeaker in Embodiment 2 of the present invention; Figure 9 This is a cross-sectional view of the magnetic circuit device for a loudspeaker in Embodiment 2 of the present invention; Figure 10 This is a schematic diagram of the simulated magnetic saturation region of the magnetic circuit device for a loudspeaker in Embodiment 2 of the present invention; Figure 11 This is a schematic diagram of the magnetic circuit device for a loudspeaker in Embodiment 3 of the present invention; Figure 12 This is a structural cross-sectional view of the magnetic circuit device for a loudspeaker in Embodiment 3 of the present invention; Figure 13 This is a schematic diagram of the simulated magnetic saturation region of the magnetic circuit device for a loudspeaker in Embodiment 3 of the present invention; Figure 14 This is a schematic diagram of the magnetic circuit device for a loudspeaker in Embodiment 4 of the present invention; Figure 15 This is a cross-sectional view of the magnetic circuit device for a loudspeaker in Embodiment 4 of the present invention; Figure 16 This is a schematic diagram of the simulated magnetic saturation region of the magnetic circuit device for a loudspeaker in Embodiment 4 of the present invention.

[0018] In the picture: 1. Magnet; 2. Electrode; 21. Thinning ring groove; 3. T-iron; 31. Base; 311. Chassis; 312. Side ring; 313. Bottom ring; 32. Center post; 321. Convex tooth; 322. Blind hole; 323. Thinning hole; 4. Voice coil; 5. Magnetic path; 6. Magnetic saturation region; 7. Metal cap. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] like Figures 1 to 16 As shown, the present invention provides a magnetic circuit device for a loudspeaker and a loudspeaker.

[0024] Example 1: Reference Figures 1 to 4 The magnetic circuit device for this loudspeaker includes a magnet 1, a pole piece 2, a T-iron 3, and a voice coil 4. The pole piece 2 is disposed on one side of the magnet 1 and is attached to one side of the magnet 1; the T-iron 3 includes a base 31 and a center post 32, the base 31 is located on the other side of the magnet 1 and is attached to the other side of the magnet 1, and the center post 32 passes through the magnet 1 and the pole piece 2; the voice coil 4 is inserted into the pole piece 2 and sleeved on the center post 32; wherein, the side of the magnet 1 facing the pole piece 2, the pole piece 2, the center post 32, the base 31, and the side of the magnet 1 facing the base 31 form a closed magnetic path 5, and a thinning section is provided in the path of the magnetic path 5 to form a magnetic saturation region 6, the equivalent relative permeability of the magnetic saturation region 6 being less than 500.

[0025] The magnetic field lines generated by magnet 1 travel along the closed magnetic path 5, originating from the side of magnet 1 facing pole piece 2, passing through pole piece 2, voice coil 4, center post 32, and base 31, before returning to the side of magnet 1 facing base 31. Voice coil 4 is located within the magnetic field between pole piece 2 and center post 32. When an alternating current, varying with the audio signal, is applied, voice coil 4 experiences a synchronously changing Ampere force, resulting in reciprocating vibration. This converts the electrical signal into mechanical vibration, ultimately driving the diaphragm to push air and produce sound. A thinning section is incorporated within magnetic path 5 to form a magnetic saturation region 6, with an equivalent relative permeability below 500. This creates a high magnetic reluctance barrier near voice coil 4, significantly reducing the total amount of alternating magnetic flux and thus substantially decreasing inductance. With reduced inductance, the high-frequency radiated sound power of the speaker does not rapidly decay with increasing frequency, improving high-frequency extension and effectively enhancing the speaker's frequency response. Furthermore, the formation of the magnetic saturation region 6 allows the inductance of the voice coil 4 to remain relatively stable, avoiding current distortion caused by sudden changes in inductance when the voice coil 4 undergoes large displacement. It also reduces harmonic distortion, thereby improving sound quality. Therefore, during the production of this loudspeaker magnetic circuit device, only a thinning section needs to be added to the path of the magnetic passage 5 to form the magnetic saturation region 6, which can effectively improve the frequency response and distortion of the loudspeaker and enhance sound quality. The thinning section can be added within the existing process, without adding any new steps, lengthening the production cycle, or requiring additional auxiliary materials, thus ensuring that the overall manufacturing cost of mass-producing loudspeaker magnetic circuit devices is not increased.

[0026] Specifically, both the pole piece 2 and the magnet 1 are annular. The magnet 1 is clamped between the base 31 and the pole piece 2. The end of the central column 32 away from the base 31 can pass through the pole piece 2 and is spaced apart from it. The voice coil 4 is inserted between the pole piece 2 and the central column 32, with the inner side of the voice coil 4 spaced apart from the central column 32 and the outer side of the voice coil 4 spaced apart from the pole piece 2. The height L of the central column 32 is preferably greater than the stroke of the voice coil 4, so that the voice coil 4 is always within the magnetic field region supported by the central column 32 within the positive and negative vibration ranges, avoiding a sudden change in the magnetic field when the voice coil 4 reaches the edge of its stroke.

[0027] Optionally, the central column 32 has a plurality of convex teeth 321 distributed circumferentially around the central column 32, the convex teeth 321 forming a magnetic saturation region 6.

[0028] Specifically, the edge of the central column 32 furthest from the base 31 is locally concave, thus forming multiple spaced protrusions 321. The thickness of the protrusions 321 can be between 1.5mm and 2.5mm. The multiple protrusions 321 make the central column 32 appear serrated overall, and the wall thickness h0 at the protrusion 321 location is significantly reduced. The relationship between the cross-sectional area A and the wall thickness h0 in the magnetic path 5 is A=2πRh0, which is directly proportional to the wall thickness h0. The relationship between the magnetic flux density B and the cross-sectional area A is B=φ / A, which is inversely proportional to the magnetic flux density B. The equivalent relative permeability μ1=u2 / μ0, where μ2=B / H and μ0=4π×10 -7 H / m, equivalent relative permeability μ1 = B / μ0H, where H is the magnetic field strength. In summary, the equivalent relative permeability μ1 is inversely proportional to the wall thickness h0. However, as h0 decreases, the magnetic flux density B of the central column 32 increases and exceeds the magnetic flux density saturation threshold B of the central column 32. s When h0 decreases and B increases, the rate of increase of magnetic flux density B decreases significantly, while the equivalent relative permeability decreases rapidly. This results in the equivalent relative permeability of the magnetic saturation region 6 formed by the tooth 321 as a thinning part being lower than 500.

[0029] Optionally, the spacing between two adjacent teeth 321 increases and then decreases along the axis of the central column 32 towards the base 31.

[0030] Specifically, the concave surface between two adjacent protrusions 321 is arc-shaped, so that the wall thickness of the upper part of the protrusion 321 decreases while the wall thickness of the lower part increases. This makes the distance between two adjacent protrusions 321 first increase and then decrease along the axis of the central column 32 towards the base 31. By precisely controlling the curvature and size of the concave part during processing, the size of the magnetic saturation region 6 can be precisely controlled. This ensures that the magnetic saturation region 6 is not too small and cannot completely block the alternating magnetic flux, resulting in insufficient inductance reduction, nor is it too large and encroaches on the main magnetic circuit space, causing loss of main magnetic flux. This ensures that the inductance fluctuation of the voice coil 4 is minimal throughout its entire vibration stroke, avoiding abnormal situations such as force distortion and dynamic displacement of the voice coil 4.

[0031] Optionally, a metal cap 7 is fitted onto the end of the central column 32 that is away from the base 31.

[0032] Specifically, the metal cap 7 consists of a top cover and a collar, which are integrated into one piece. The top cover closes the end face of the collar, and a through hole is provided in the center of the top cover. The collar is fitted onto the outside of the center post 32, which is the side of the center post closest to the voice coil 4, and the inner wall of the collar fits against the outer wall of the center post 32. The metal cap 7 can be made of aluminum, which has a certain degree of deformation capability. When fitted, it forms an interference fit with the center post 32, thus eliminating the need for gluing or other processes.

[0033] When an alternating audio current is passed through the voice coil 4, an alternating magnetic field is generated around it. The metal cap 7 is fitted on the center post 32. As a highly conductive but non-magnetic metal, it will induce strong ring-shaped eddy currents in the alternating magnetic field, thereby generating significant Joule thermal damage. This greatly consumes the energy of the alternating magnetic field of the voice coil 4, effectively canceling out a large amount of alternating magnetic flux, and preventing the center post 32 from concentrating the magnetic flux. This further reduces the inductance and improves the high-frequency response and distortion performance of the speaker.

[0034] The loudspeaker includes a frame and a magnetic circuit device for the loudspeaker as described above. The magnetic circuit device for the loudspeaker is disposed in the frame.

[0035] During the manufacturing process of this loudspeaker, the magnetic circuit device only needs to be machined with a thinning part in the magnetic path 5 to form a magnetic saturation region 6, which can effectively improve the frequency response and distortion performance of the loudspeaker and improve the sound quality. There is no need to add structures such as short-circuit rings, which can shorten the loudspeaker manufacturing process and reduce the amount of auxiliary materials used, thereby effectively reducing the overall manufacturing cost of loudspeakers in mass production.

[0036] Reference Figures 5 to 7 Based on actual simulation comparisons, the speaker with a magnetic saturation region 6 and a metal cap 7 in the magnetic path 5 of this invention shows significant improvements in frequency response and distortion compared to the speaker with an aluminum short-circuit ring in the traditional structure. The total weight of this invention is 0.52 kg, and the maximum temperature of the voice coil 4 is 110°C, while the total weight of the traditional structure is 0.58 kg, and the maximum temperature of the voice coil 4 reaches 123°C.

[0037] Example 2: Based on Example 1, the difference between this example and Example 1 lies in the location of the thinning portion.

[0038] Reference Figures 8 to 10 Optionally, the base 31 includes a chassis 311, a side ring 312 disposed on the edge of the chassis 311, and a bottom ring 313 connected to the side ring 312. The bottom ring 313 abuts against the bottom wall of the magnet 1. The central column 32 is disposed on the side of the chassis 311 facing the magnet 1. The inner or outer side of the side ring 312 is provided with a thinning groove so that the chassis 311 forms a magnetic saturation region 6.

[0039] Specifically, the chassis 311, side ring 312, and bottom ring 313 are integrated into one structure, while the central column 32 is also integrated with the chassis 311. The central column 32, chassis 311, side ring 312, and bottom ring 313 all form part of the magnetic path 5. Thinning grooves are provided on the inner or outer side of the side ring 312, reducing its wall thickness h1. The wall thickness h1 can be limited to between 2.5mm and 3.5mm, while the wall thickness of the conventional structure is around 6mm. The principle of reducing the wall thickness h1 to form the magnetic saturation region 6 is the same as that in Embodiment 1, and will not be repeated here. The inner side of the side ring 312 is the side of the side ring 312 closest to the magnet 1 and the central column 32, while the outer side of the side ring 312 is the side of the side ring 312 furthest from the magnet 1 and the central column 32.

[0040] A recessed blind hole 322 can be provided on the side of the central column 32 away from the base 31 to reduce the wall thickness of the central column 32. The blind hole 322 can be inverted conical. An insertion groove can also be provided on the outer wall of the central column 32 to accommodate the metal cap 7. The thickness of the insertion groove is the same as the thickness of the metal cap 7, so that the metal cap 7 can be completely embedded on the outer side of the central column 32.

[0041] Example 3: Based on Example 1, the difference between this example and Example 1 lies in the location of the thinning portion.

[0042] Reference Figures 11 to 13 Optionally, a thinning hole 323 is formed inward on the side of the central column 32 away from the base 31. The depth of the thinning hole 323 is greater than half the height of the central column 32, and the diameter of the thinning hole 323 is greater than the radius of the central column 32, so that a magnetic saturation region 6 is formed on the side wall of the central column 32.

[0043] Specifically, a thinning hole 323 is formed inside the central column 32 towards the base 31. The thinning hole 323 is a blind hole 322, and its depth and diameter are both relatively large, so that the wall thickness h2 of the central column 32 after the thinning hole 323 is formed is significantly reduced. In this embodiment, h2 can be between 1.5mm and 2.5mm, and the depth of the thinning hole 323 is equal to the height of the central column 32. The principle of the reduction of wall thickness h2 as the magnetic saturation region 6 formed by the thinning part is the same as the principle of the magnetic saturation region 6 formed in Embodiment 1, and will not be repeated here.

[0044] Optionally, the thinning hole 323 includes a vertical section and a curved section distributed along the axis of the central column 32 toward the base 31. The diameter of the hole in the vertical section remains unchanged, while the diameter of the hole in the curved section decreases along the axis of the central column 32 toward the base 31 so that the wall thickness gradually increases.

[0045] Specifically, by dividing the thinning hole 323 into a vertical section and a curved section, the magnetic saturation region 6 is concentrated in the vertical section, which is directly opposite the voice coil 4. This allows the magnetic saturation region 6 to accurately cover the overlapping area with the voice coil 4 when it vibrates negatively, effectively reducing the possibility of inductive nonlinear distortion caused by the large displacement of the voice coil 4, and improving the frequency response and distortion of the loudspeaker.

[0046] A slot can also be provided on the side of the center post 32 facing the voice coil 4 to accommodate the metal cap 7. The thickness of the slot is the same as the thickness of the metal cap 7, so that the metal cap 7 can be completely embedded on the outside of the center post 32.

[0047] Example 4: Based on Example 1, the difference between this example and Example 1 lies in the location of the thinning portion.

[0048] Reference Figures 14 to 16 Optionally, a thinning annular groove 21 is provided on the side of the electrode 2 away from the magnet 1 and near the central column 32 to form a magnetic saturation region 6.

[0049] Specifically, the pole piece 2 is annular, with a through hole in its center for the voice coil 4 to be inserted. The inner side of the pole piece 2 is spaced apart from the voice coil 4, and the inner side of the voice coil 4 is spaced apart from the center post 32. A thinning annular groove 21 is provided on the pole piece 2 near the center post 32, which significantly reduces the local wall thickness of the pole piece 2. Based on the principle in Embodiment 1, a magnetic saturation region 6 can be formed at this thinned part. The sidewall of the thinning annular groove 21 near the center post 32 is inclined, and the inclination angle is less than 45°. This ensures that a uniform magnetic saturation region 6 is formed on the entire side of the pole piece 2 near the voice coil 4, thereby ensuring that the force coefficient of the voice coil 4 remains symmetrical at different positions during vibration.

[0050] A recessed blind hole 322 can be provided on the side of the center post 32 away from the base 31 to reduce the wall thickness of the center post 32. The blind hole 322 can be inverted conical. A insertion slot can also be provided on the side of the center post 32 facing the voice coil 4 to accommodate the metal cap 7. The thickness of the insertion slot is the same as the thickness of the metal cap 7, so that the metal cap 7 can be completely embedded on the outside of the center post 32.

[0051] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A magnetic circuit device for a loudspeaker, characterized in that, include: magnet; An electrode is disposed on one side of the magnet and is attached to one side of the magnet. The T-iron includes a base and a central column. The base is located on the other side of the magnet and is in contact with the other side of the magnet. The central column passes through the magnet and the pole piece, and the central column and the pole piece are spaced apart. The voice coil is inserted between the pole piece and the center post; The magnet, the side facing the pole piece, the pole piece, the central column, the base, and the side facing the base form a closed magnetic path. A thinning section is provided in the path of the magnetic path to form a magnetic saturation region. The equivalent relative permeability of the magnetic saturation region is less than 500.

2. The magnetic circuit device for a loudspeaker according to claim 1, characterized in that, The central column has multiple convex teeth that are spaced apart around the central column in a circumferential direction, and the convex teeth form the magnetic saturation region.

3. The magnetic circuit device for a loudspeaker according to claim 2, characterized in that, The distance between two adjacent protrusions increases first and then decreases along the axis of the central column towards the base.

4. The magnetic circuit device for a loudspeaker according to claim 1, characterized in that, The base includes a chassis, a side ring disposed on the edge of the chassis, and a bottom ring connected to the side ring. The bottom ring abuts against the bottom wall of the magnet. The central column is disposed on the side of the chassis facing the magnet. Thinning grooves are provided on the inner or outer side of the side ring so that the chassis forms the magnetic saturation region.

5. The magnetic circuit device for a loudspeaker according to claim 1, characterized in that, The central column has a recessed thinning hole on the side away from the base. The depth of the thinning hole is greater than half the height of the central column, and the diameter of the thinning hole is greater than the radius of the central column, so that the sidewall of the central column forms the magnetic saturation region.

6. The magnetic circuit device for a loudspeaker according to claim 5, characterized in that, The thinning hole includes a vertical section and a curved section distributed along the central column axis toward the base. The diameter of the vertical section remains constant, while the diameter of the curved section decreases along the central column axis toward the base so that the wall thickness gradually increases.

7. The magnetic circuit device for a loudspeaker according to claim 1, characterized in that, A thinning groove is formed on the side of the electrode away from the magnet and near the central column to create the magnetic saturation region.

8. The magnetic circuit device for a loudspeaker according to claim 7, characterized in that, The sidewall of the thinning annular groove near the central column is inclined, and the inclination angle is less than 45°.

9. The magnetic circuit device for a loudspeaker according to any one of claims 1 to 8, characterized in that, A metal cap is fitted onto the end of the central column that is away from the base.

10. A loudspeaker, characterized in that, include: frame; The magnetic circuit device for a loudspeaker as described in any one of claims 1 to 9 is disposed in the frame.

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