A magnetic circuit unit and a loudspeaker using the same

Abstract

The present invention discloses a magnetic circuit unit and a loudspeaker using the magnetic circuit unit, comprising: a permanent magnet made of rare earth material, a U iron, and a washer; the permanent magnet is placed in a receiving groove of the U iron; a recess is provided in the center of the permanent magnet; and the washer covers the surface of the permanent magnet facing away from the bottom. The permanent magnet is roughly cylindrical, and the recess is roughly a cylindrical through hole; the axis of the permanent magnet coincides with the axis of the recess; and the washer is annular. The diameter of the recess is 20% to 70% of the diameter of the permanent magnet. The diameter of the recess is 35% of the diameter of the permanent magnet. There are two permanent magnets, including an outer magnet and an inner magnet; a receiving portion is provided in the center of the outer magnet to cover the inner magnet; the grade of the outer magnet is larger than that of the inner magnet; and the inner magnet is solid throughout or has a cavity in the center.

Description

Technical Field

[0001] The present application relates to the technical field of loudspeaker devices, and in particular to a magnetic circuit unit and a loudspeaker using the magnetic circuit unit. Background Art

[0002] Based on the structure of the speaker, speakers can be roughly divided into external magnetic speakers and internal magnetic speakers; both types of speakers include magnetic circuit units; the magnetic conductive component in the magnetic circuit unit of the external magnetic speaker is T iron, and the magnetic conductive component of the internal magnetic speaker is U iron; the magnetic conductive component is also used to place magnets. The magnet is a key component in the magnetic circuit of the speaker unit and determines the performance of the speaker.

[0003] T has an iron core, so the permanent magnet corresponding to the T iron will be provided with a corresponding avoidance groove; the magnetic conductive component is an internal magnetic speaker of the U iron. In the inherent cognition of technical personnel in this field, the use of the permanent magnet placed in the U iron does not require additional modification, and the entire piece only needs to be placed in the groove of the U iron.

[0004] Thanks to the use of permanent magnets made of rare earth materials in internal magnetic speakers, internal magnetic speakers can be smaller in size and have better performance than other types of speakers. However, the price of permanent magnets made of rare earth materials continues to rise, and the rare earth elements contained in them are still non-renewable resources. At the same time, the mining of rare earth mines also causes serious environmental pollution.

[0005] In the design of the magnetic circuit of the internal magnetic loudspeaker, the structure of the entire rare earth magnet is not optimized to reduce the material cost of producing the loudspeaker. Summary of the Invention

[0006] The present invention mainly addresses the above problems and proposes a magnetic circuit unit and a loudspeaker using the magnetic circuit unit, aiming to solve the technical problems in the background technology.

[0007] To achieve the above-mentioned objectives, the present invention provides a magnetic circuit unit, comprising: a permanent magnet made of rare earth material, a U iron, and a washer; the permanent magnet is placed in an accommodating groove of the U iron; a recess is provided in the center of the permanent magnet; and the washer covers the surface of the permanent magnet facing away from the bottom.

[0008] Furthermore, the permanent magnet is substantially a cylinder, the recess is substantially a cylindrical through hole; the axis of the permanent magnet coincides with the axis of the recess; and the washer is annular.

[0009] Furthermore, the diameter length of the recessed portion is 20% to 70% of the diameter length of the permanent magnet.

[0010] Furthermore, the diameter length of the recessed portion is 35% of the diameter length of the permanent magnet.

[0011] Furthermore, there are two permanent magnets, which include an outer magnet and an inner magnet; a receiving portion is provided in the center of the outer magnet to cover the inner magnet; the grade of the outer magnet is larger than that of the inner magnet; the inner magnet is solid throughout or has a cavity in the center.

[0012] Furthermore, the number of the permanent magnets is multiple, including an outer layer magnet and multiple inner layer magnets that are nested together; the center of the outer layer magnet is provided with a receiving portion that covers the outermost inner layer magnet among the multiple inner layer magnets; the brand of the outer layer magnet is greater than the brand of the multiple inner layer magnets; the brand of the magnet relative to the outer layer among the multiple inner layer magnets is greater than the brand of the inner layer magnet nested together.

[0013] Furthermore, the innermost magnet among the plurality of inner magnets is solid or has a cavity in the center.

[0014] A magnetic circuit unit includes a permanent magnet made of rare earth material, a U-iron, and a washer; the permanent magnet is roughly a rectangular parallelepiped; the permanent magnet is placed in a receiving groove of the U-iron; the permanent magnet includes a central magnet and one or more side magnets respectively arranged in parallel on both sides of the central magnet; the brand of the side magnets is larger than that of the central magnet, and the washer covers the surface of the permanent magnet facing away from the bottom.

[0015] A loudspeaker employs the aforementioned magnetic circuit unit.

[0016] Compared with the prior art, the magnetic circuit unit and the loudspeaker using the magnetic circuit unit provided by the present invention can reduce the use of rare earth magnets such as permanent magnets by setting a recessed portion in the permanent magnet magnet in the magnetic circuit unit whose magnetic conductive component is U iron in an internal magnetic loudspeaker, thereby reducing the cost of the magnetic circuit unit and reducing the pollution caused by rare earth mining to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a cross-sectional view of the magnetic circuit unit of a conventional internal magnetic speaker.

[0018] Figure 2 This is a schematic diagram of the three-dimensional structure of an embodiment of a magnetic circuit unit of the present application.

[0019] Figure 3 for Figure 3 sectional view of .

[0020] Figure 4 This is a cross-sectional view of a 20 mm through hole in a recessed portion of a 28.4 mm diameter permanent magnet in a magnetic circuit unit of the present application.

[0021] Figure 5This is a cross-sectional view of a magnetic circuit unit of the present application, in which a permanent magnet is divided into two, an outer magnet and an inner magnet.

[0022] Figure 6 This is a cross-sectional view of another embodiment of a magnetic circuit unit of the present application, in which the permanent magnet is divided into two, an outer magnet and an inner magnet.

[0023] Figure 7 This is a cross-sectional view of a magnetic circuit unit of the present application, in which the permanent magnet is divided into two, an outer magnet and an inner magnet, and the inner magnet is provided with a cavity.

[0024] Figure 8 This is a cross-sectional view of a magnetic circuit unit of the present application in which there are multiple permanent magnets, including an outer magnet and two inner magnets that are intertwined with each other.

[0025] Figure 9 This is a schematic diagram of the three-dimensional structure of an embodiment of a magnetic circuit unit of the present application in which the permanent magnet is a rectangular parallelepiped.

[0026] Figure 10 for Figure 9 sectional view of .

[0027] Figure 11 This is a schematic diagram of the three-dimensional structure of another embodiment of the magnetic circuit unit of the present application in which the permanent magnet is a rectangular parallelepiped.

[0028] Figure 12 for Figure 11 sectional view of .

[0029] Figure 13 This is a cross-sectional view of another embodiment of a magnetic circuit unit of the present application in which the permanent magnet is a rectangular parallelepiped.

[0030] Figure 14 This is the magnetic field distribution diagram of a magnet with a diameter of 28.4 mm, a thickness of 6 mm, and a brand of N40 in the magnetic circuit unit of a conventional internal magnetic speaker.

[0031] Figure 15 for Figure 14 Magnetic induction intensity curve of the magnet in the magnetic gap.

[0032] Figure 16 This is a magnetic field distribution diagram of a permanent magnet with a diameter of 28.4 mm, a thickness of 6 mm, and a brand of N40 in a magnetic circuit unit of the present application, and a recessed portion with a cylindrical through hole with a diameter of 6 mm.

[0033] Figure 17 This is a magnetic field distribution diagram of a permanent magnet with a diameter of 28.4 mm, a thickness of 6 mm, and a brand of N40 in a magnetic circuit unit of the present application, and a recessed portion with a cylindrical through hole with a diameter of 10 mm.

[0034] Figure 18This is a magnetic field distribution diagram of a permanent magnet with a diameter of 28.4 mm, a thickness of 6 mm, and a brand of N40 in a magnetic circuit unit of the present application, and a recessed portion with a cylindrical through hole with a diameter of 20 mm.

[0035] Figure 19 for Figure 14 - Figure 18 Comparison curve of magnetic induction intensity in the magnetic gap of the middle magnet.

[0036] Figure 20 This is a magnetic field distribution diagram of a permanent magnet with a thickness of 6 mm in a magnetic circuit unit of the present application, with an outer layer magnet of 28.4 mm in outer diameter and brand N40, and an inner layer magnet of 10 mm in outer diameter and brand N35 provided in its receiving portion.

[0037] Figure 21 This is a magnetic field distribution diagram of a permanent magnet with a thickness of 6 mm in a magnetic circuit unit of the present application, with an outer layer magnet of 28.4 mm in outer diameter and brand N40, and an inner layer magnet of 20 mm in outer diameter and brand N35 provided in its receiving portion.

[0038] Figure 22 This is a magnetic field distribution diagram of a permanent magnet with a thickness of 6 mm in a magnetic circuit unit, an outer magnet with an outer diameter of 28.4 mm and a brand N40, and an inner magnet with an outer diameter of 20 mm and a brand N32 provided in its receiving portion.

[0039] Figure 23 for Figure 14 、 Figure 18 、 Figure 20 - Figure 22 Comparison curve of magnetic induction intensity in the magnetic gap of the middle magnet.

[0040] Figure 24 This is a magnetic field distribution diagram of a permanent magnet with a thickness of 6 mm in a magnetic circuit unit, an outer magnet with an outer diameter of 28.4 mm and brand N40, and an inner magnet with an outer diameter of 10 mm and brand N35 and a ring with a diameter of 10 mm and brand N32 in its accommodating portion.

[0041] Figure 25 This is a magnetic field distribution diagram of a permanent magnet with a thickness of 6 mm in a magnetic circuit unit, with an outer magnet of 28.4 mm in outer diameter and brand N40, and an inner magnet of 10 mm in outer diameter and brand N35 in the receiving part, and a cylindrical cavity magnet with a diameter of 10 mm.

[0042] Figure 26 for Figure 14 、 Figure 18 、 Figure 20 - Figure 22 、 Figure 24 、 Figure 25 Comparison curve of magnetic induction intensity in the magnetic gap of the middle magnet.

[0043] Reference numerals shown in the figure: 1, permanent magnet; 101, recessed portion; 110, outer magnet; 120, inner magnet; 121, cavity; 130, middle magnet; 140, side magnet; 2, U iron; 3, washer. DETAILED DESCRIPTION

[0044] Please refer to Figure 2 - Figure 6 、 Figure 14 - Figure 26 This embodiment provides a magnetic circuit unit, including a permanent magnet 1 made of rare earth material, a U iron 2, and a washer 3; the permanent magnet 1 is placed in the accommodating groove of the U iron 2; a recess 101 is opened in the center of the permanent magnet 1; the washer 3 covers the surface of the permanent magnet 1 away from the bottom.

[0045] During improved testing of the permanent magnet 1, it was found that the magnetic field strength at the center of the permanent magnet 1 and washer 3 was significantly lower than that at the periphery. Therefore, the center of the permanent magnet 1 and washer 3 was removed to form a recessed portion 101. The magnetic field strength provided by the permanent magnet 1 and washer 3 is, to a certain extent, within an acceptable range compared to the magnetic field strength of a single, integral permanent magnet 1. The impact on the performance of the magnetic circuit unit is also within an acceptable range. Recessed portion 101 can be a through hole or a blind hole.

[0046] By providing a recess 101 in the permanent magnet 1 in the magnetic circuit unit of the internal magnetic speaker, in which the magnetic conductive component is the U iron 2, the use of the permanent magnet 1, which is a rare earth material, can be reduced, thereby reducing the cost of the magnetic circuit unit and reducing the pollution caused by rare earth mining to a certain extent.

[0047] Providing a recessed portion 101 on the permanent magnet 1 not only reduces material usage and reduces costs, but the presence of the recessed portion 101 also reduces the weight of the magnetic circuit unit, making the speaker lighter and easier to transport and carry, and increases the surface area of ​​the permanent magnet 1. When the speaker is working at high power, it will generate heat, and the heat will cause high temperature in the magnetic gap. For magnets made of rare earth materials, it may cause irreversible magnetic degradation, and the magnet will slowly demagnetize until it has no magnetism. The recessed portion 101 increases the surface area of ​​the permanent magnet 1, reduces heat energy storage, makes it easier for the permanent magnet 1 to dissipate heat, and extends the service life of the permanent magnet 1.

[0048] Please refer to Figure 3 - Figure 4 The permanent magnet 1 is roughly cylindrical, and the recessed portion 101 is roughly a cylindrical through hole; the axis of the permanent magnet 1 coincides with the axis of the recessed portion 101; and the washer 3 is annular.

[0049] The washer 3 corresponds to the permanent magnet 1. After a cylindrical through hole is set in the permanent magnet 1, the washer 3 is ring-shaped and corresponds to the recessed portion 101. The magnetic field strength of the central part of the permanent magnet 1 and the washer 3 is lower than that of the periphery. Therefore, the washer 3 is designed in a ring shape, and the impact on the performance of the magnetic circuit unit is also within an acceptable range.

[0050] Please refer to Figure 3 - Figure 4 、 Figure 16 - Figure 19 In some embodiments, the diameter of the recessed portion 101 is 20% to 70% of the diameter of the permanent magnet 1 .

[0051] Taking a cylindrical rare earth magnet with a brand of N40, a diameter of 28.4 mm and a thickness of 6 mm as an example, after testing, recesses 101 with diameters of 6 mm, 10 mm and 20 mm were dug out from the center of the magnet, and the magnetic field strength of the magnet was analyzed and compared. Curves a, b, c and d correspond to the magnetic induction intensities in the magnetic gap when the magnet is a whole structure, the recess 101 is 6 mm, the recess 101 is 10 mm and the recess 101 is 10 mm, respectively. These permanent magnets 1 were then applied to a magnetic circuit unit and assembled into a loudspeaker for testing and comparison. Within an acceptable range, when the diameter length of the recess 101 is less than 35% of the diameter length of the permanent magnet 1, the overall performance of the loudspeaker is less affected to an acceptable extent.

[0052] Preferably, the diameter of the recessed portion 101 is 35% of the diameter of the permanent magnet 1 .

[0053] After repeated tests, it was determined that the diameter of the recessed portion 101 is less than 35% of the diameter of the permanent magnet 1 , which can reduce the amount of magnets used and reduce costs while ensuring better magnetic induction strength of the permanent magnet 1 .

[0054] Please refer to Figure 5 - Figure 7 There are two permanent magnets 1, which include an outer magnet 110 and an inner magnet 120; a receiving portion is provided in the center of the outer magnet 110 to cover the inner magnet 120; the grade of the outer magnet 110 is larger than that of the inner magnet 120; the inner magnet 120 is solid throughout or has a cavity in the center.

[0055] In some embodiments, the accommodating portion is a cylindrical through hole, or may be a blind hole, and the accommodating portion is the recessed portion 101 of the original single permanent magnet 1 .

[0056] The grade of rare earth magnets is positively correlated with their price; the higher the grade, the more expensive they are. Providing only a recessed portion 101 in a permanent magnet 1 is not the most optimal design, as the magnetic field strength of a magnet is continuously distributed from weak to strong from the center to the periphery. Following this pattern, magnets of different grades are arranged in a distributed pattern from the center to the edge, with the grade of the outer magnets 110 set to be greater than that of the inner magnets 120. For permanent magnets 1 with recessed portions 101, the recessed portions 101 are filled with inner magnets 120 of a relatively low grade to compensate for the low magnetic induction intensity caused by the empty recessed portions 101, thereby achieving the highest cost-effectiveness.

[0057] Please refer to Figure 14 、 Figure 18 、 Figure 20 - Figure 23 , taking the outer magnet 110 brand of N40 and the inner magnet 120 brand of N35 and N32 as an example, after different sizes of the recessed portion 101 and different brands of inner magnets 120 are built into the recessed portion 101 for combination comparison, the outer magnet 110 brand is N40 and the diameter is 28.4 mm; curve e is the magnetic induction intensity in the magnetic gap of the permanent magnet 1 using a whole piece of N40 brand magnet, curve f is the magnetic induction intensity in the magnetic gap of the permanent magnet 1 with a recessed portion 101 diameter of 6 mm, and curve g is the magnetic induction intensity in the magnetic gap of the permanent magnet 1 with a recessed portion 101 diameter of Curve h is the magnetic induction intensity in the magnetic gap when the diameter of the through hole of the outer magnet 110 is 10 mm and the brand of the inner magnet 120 is N35. Curve i is the magnetic induction intensity in the magnetic gap when the diameter of the through hole of the outer magnet 110 is 20 mm and the brand of the inner magnet 120 is N35. Curve j is the magnetic induction intensity in the magnetic gap when the diameter of the through hole of the outer magnet 110 is 20 mm and the brand of the inner magnet 120 is N32. Curve k is the magnetic induction intensity in the magnetic gap when the diameter of the recessed portion 101 of the permanent magnet 1 is 20 mm.

[0058] After comparative analysis, except for curve g which deviates more from curve e than curve k, other scheme combinations are close to curve e. Therefore, a low-cost scheme can be selected to replace the permanent magnet 1 with a whole high-grade magnet to achieve the highest cost-effectiveness.

[0059] The schemes corresponding to curve h and curve i show that the magnetic field strength loss of these two designs is small, basically maintained between the permanent magnet 1 without the recess 101 and the recess 101 with a length of 6 mm, which is a more preferred scheme.

[0060] Please refer to Figure 8The number of the permanent magnets 1 is multiple, including an outer layer magnet 110 and multiple inner layer magnets 120 that are nested with each other; the outer layer magnet 110 is provided with a receiving portion at its center to enclose the outermost inner layer magnet 120 among the multiple inner layer magnets 120; the brand of the outer layer magnet 110 is greater than the brand of the multiple inner layer magnets 120; the brand of the magnet relative to the outer layer among the multiple inner layer magnets 120 is greater than the brand of the inner layer magnet 120 nested with it.

[0061] Please refer to Figure 7 The innermost magnet among the plurality of inner magnets 120 is solid or has a cavity in the center.

[0062] The inner layer magnets 120 are arranged in a plurality and are interlocked with each other, so as to reduce the usage of high-grade and high-priced permanent magnets 1, reduce material costs, and improve the cost performance of the magnetic circuit unit.

[0063] Please refer to Figure 14 、 Figure 18 、 Figure 20 - Figure 22 、 Figure 24 - Figure 26 , taking the outer magnet 110 brand N40 and the inner magnet 120 brand N35 and N32 as an example, after different recessed portion 101 sizes and different brands of inner magnets 120 are built into the recessed portion 101 for combination comparison, the outer magnet 110 brand is N40, with a diameter of 28.4 mm; curve l is the magnetic induction intensity in the magnetic gap of the permanent magnet 1 using a whole piece of N40 brand magnet, curve m is the magnetic induction intensity in the magnetic gap of the permanent magnet 1 with a recessed portion 101 diameter of 6 mm, curve n is the magnetic induction intensity in the magnetic gap of the permanent magnet 1 with a recessed portion 101 diameter of 10 mm, curve o is the magnetic induction intensity in the magnetic gap of the outer magnet 110 with a through hole diameter of 10 mm and the inner magnet 120 brand N35, curve p is the magnetic induction intensity in the magnetic gap of the outer magnet 110 with a through hole diameter of 20 mm, The magnetic induction intensity in the magnetic gap when the inner magnet 120 is of N35 grade is shown. Curve q shows the magnetic induction intensity in the magnetic gap when the through-hole diameter of the outer magnet 110 is 20 mm and the inner magnet 120 is of N32 grade. Curve r shows the magnetic induction intensity in the magnetic gap when the outer magnet 110 surrounds two inner magnets 120, the innermost inner magnet 120 has a diameter of 10 mm and is of N32 grade, and the inner magnet 120 of the innermost inner magnet 120 and the outer magnet 110 form a circular ring with a width of 5 mm and is of N35 grade. Curve s shows the magnetic induction intensity in the magnetic gap when the through-hole diameter of the outer magnet 110 is 15 mm and the inner magnet 120 is of N35 grade, and the through-hole diameter of the inner magnet 120 is 10 mm. Curve t shows the magnetic induction intensity in the magnetic gap when the recess 101 of the permanent magnet 1 has a diameter of 20 mm.

[0064] The scheme corresponding to curve r shows that the magnetic field strength loss of the three inner magnets 120 arranged in an interlocking manner is basically maintained between the design without a hole and the design with a 6 mm recess 101. If the centermost N32 inner magnet 120 is removed, that is, the scheme corresponding to curve s, the center value is only slightly lower by 1.5% than the design with a 10 mm through hole.

[0065] Therefore, this low-cost solution can be selected to replace the permanent magnet 1 with a whole piece of high-grade magnet to achieve the highest cost-effectiveness.

[0066] It is worth noting that, for the sake of ease of understanding, the above description describes the recessed portion 101 as being dug out from the permanent magnet 1. This does not mean that the recessed portion 101 is punched or drilled out from the entire permanent magnet 1 at a later stage. Rather, the recessed portion 101 is formed by plastic molding of the mold when the permanent magnet 1 is sintered together with the permanent magnet 1, and is not formed by secondary processing.

[0067] Please refer to Figure 7 - Figure 13 A magnetic circuit unit includes a permanent magnet 1 made of rare earth material, a U iron 2, and a washer 3; the permanent magnet 1 is roughly a rectangular parallelepiped; the permanent magnet 1 is placed in the accommodating groove of the U iron 2; the permanent magnet 1 includes a central magnet 130 and one or more side magnets 140 respectively arranged on both sides of the central magnet 130; the brand of the side magnets 140 is larger than the brand of the central magnet 130, and the washer 3 covers the surface of the permanent magnet 1 facing away from the bottom.

[0068] This magnetic circuit unit is used when the speaker is square as a whole, so as to avoid the permanent magnet 1 being set as a whole in the magnetic circuit unit, reduce the use of rare earth magnets such as the permanent magnet 1, reduce the cost of the magnetic circuit unit, and reduce the pollution caused by rare earth mining to a certain extent.

[0069] The present invention also provides a loudspeaker using the aforementioned magnetic circuit unit.

Claims

1. A magnetic circuit unit, characterized in that: It includes a permanent magnet made of rare earth material, a U iron, and a washer; the permanent magnet is placed in the receiving groove of the U iron; a recess is opened in the center of the permanent magnet; the washer covers the surface of the permanent magnet away from the bottom; The permanent magnet is substantially cylindrical, and the recess is substantially a cylindrical through hole; the axis of the permanent magnet coincides with the axis of the recess; the washer is annular; the diameter of the recess is 20% to 70% of the diameter of the permanent magnet; There are two permanent magnets, which include an outer magnet and an inner magnet; a receiving portion is provided in the center of the outer magnet to cover the inner magnet; the grade of the outer magnet is larger than that of the inner magnet; the inner magnet is solid throughout or has a cavity in the center.

2. A magnetic circuit unit according to claim 1, characterized in that: The diameter length of the recessed portion is 35% of the diameter length of the permanent magnet.

3. A magnetic circuit unit, characterized in that: It includes a permanent magnet made of rare earth material, a U iron, and a washer; the permanent magnet is placed in the receiving groove of the U iron; a recess is opened in the center of the permanent magnet; the washer covers the surface of the permanent magnet away from the bottom; The permanent magnet is substantially cylindrical, and the recess is substantially a cylindrical through hole; the axis of the permanent magnet coincides with the axis of the recess; the washer is annular; the diameter of the recess is 20% to 70% of the diameter of the permanent magnet; There are multiple permanent magnets, including an outer layer magnet and multiple inner layer magnets that are nested together. The outer layer magnet is provided with a receiving portion at its center to enclose the outermost inner layer magnet among the multiple inner layer magnets. The outer layer magnet has a larger brand than the multiple inner layer magnets. Among the multiple inner layer magnets, the brand of the magnet opposite to the outer layer is larger than the brand of the inner layer magnet nested together.

4. A magnetic circuit unit according to claim 3, characterized in that: The innermost magnet among the plurality of inner magnets is solid or has a cavity in the center.

5. A magnetic circuit unit, characterized in that: It includes a permanent magnet made of rare earth material, a U iron, and a washer; the permanent magnet is roughly a rectangular parallelepiped; the permanent magnet is placed in the accommodating groove of the U iron; the permanent magnet includes a central magnet and one or more side magnets respectively arranged on both sides of the central magnet, and the central magnet and the side magnets are arranged along the length direction of the U iron; the brand of the side magnets is larger than that of the central magnet, and the washer covers the surface of the permanent magnet facing away from the bottom.

6. A speaker, characterized in that: A magnetic circuit unit as described in any one of claims 1 to 5 is used.

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