Speaker And Manufacturing Method Thereof

Abstract

The present invention provides a speaker with low deviation while using a ferrite magnet, wherein in one embodiment, the speaker comprises: a frame portion forming an outer shape; a magnetic field forming portion inserted and disposed in the frame portion and forming a ring-shaped space; a voice coil portion having at least a portion inserted and disposed in the ring-shaped space; a damper portion connecting the voice coil portion and the frame portion; a diaphragm connected to the voice coil portion; and a terminal portion electrically connected to the voice coil portion and disposed in the frame portion; wherein the magnetic field forming portion includes an upper plate, a magnet, and a lower plate stacked in a first direction, and the magnetic field forming portion includes a plurality of guide grooves extending from the edge in the first direction.

Description

Technology Field

[0001] The present invention relates to a speaker and a method for manufacturing the same, and to a speaker and a method for manufacturing the same that can provide consistent performance even while including a ferrite magnet. Background Technology

[0002] Generally, a speaker refers to an acoustic device that emits sound by generating compressional waves in the air. It does this by utilizing electrical signals input from sources such as amplifiers, and converting the movement of a voice coil into vibrations of a diaphragm when current flows through it within a magnetic field utilizing built-in magnets. In other words, a speaker is a device that produces sound waves by vibrating a diaphragm with electrical signals.

[0003] A speaker reproduces sound by means of an electrical signal input to a voice coil within the magnetic field of a magnet that supplies a magnetic field to the voice coil. The magnetic field plays a crucial role, and ferrite magnets and neodymium magnets are commonly used to form this field. Neodymium magnets are more expensive than ferrite magnets but can provide strong magnetic force, while ferrite magnets are widely used because, although their magnetic force is weaker, they have high coercivity and excellent magnetic retention, are inexpensive, and possess superior heat resistance.

[0004] Ferrite magnets are manufactured by placing powdered material into a mold, compressing it into a desired shape under high pressure, sintering it at high temperatures, and then magnetizing it. However, shape deviations are prone to occur due to shrinkage and deformation of the ceramic material during the compression and sintering processes. Consequently, these shape deviations can lead to performance variations in speakers using ferrite magnets or result in manufacturing defects. Prior art literature

[0005] (Patent Document 0001) KR 10-2009-0102131 A The problem to be solved

[0006] The present invention aims to solve the problems of the prior art described above by providing a speaker with low deviation while using a ferrite magnet.

[0007] Another objective of the present invention is to provide a speaker that is easy to manufacture and has small manufacturing deviations, and a method for manufacturing the speaker. means of solving the problem

[0008] To achieve the above objectives, the present invention provides the following speaker and a method for manufacturing the speaker.

[0009] In one embodiment, the present invention provides a speaker comprising: a frame portion forming an outer shape; a magnetic field forming portion inserted and disposed in the frame portion and forming a ring-shaped space; a voice coil portion having at least a portion inserted and disposed in the ring-shaped space; a damper portion connecting the voice coil portion and the frame portion; a diaphragm connected to the voice coil portion; and a terminal portion electrically connected to the voice coil portion and disposed in the frame portion; wherein the magnetic field forming portion includes an upper plate, a magnet, and a lower plate stacked in a first direction, and the magnetic field forming portion includes a plurality of guide grooves extending from the edge in the first direction.

[0010] In one embodiment, the magnetic field forming part has a square shape when viewed from the first direction, and the guide groove may be formed at the center of two sides facing each other in the magnetic field forming part when viewed from the first direction.

[0011] In one embodiment, the guide groove may be formed at the center of the four sides when viewed from the first direction.

[0012] In one embodiment, the guide groove may be formed at the corner of the magnetic field forming part when viewed from the first direction.

[0013] In one embodiment, the magnetic field forming part is insert injection molded into the frame part, and the frame part includes a cover part that covers the edge of the magnetic field forming part in the first direction, and the cover part may include a cover groove formed at a position corresponding to the guide groove.

[0014] In one embodiment, the cover portion includes a first cover portion covering a first surface adjacent to the diaphragm in the magnetic field forming portion and a second cover portion covering a second surface facing the first surface, wherein the first cover portion has a first cover length extending from the edge of the magnetic field forming portion that is longer than the depth of the guide groove, and the second cover portion may include the cover groove.

[0015] In one embodiment, the magnetic field forming part has a square shape when viewed from the first direction, and the guide groove is formed at the center of two sides facing each other in the magnetic field forming part when viewed from the first direction, and the lower plate includes a circular pole piece protruding in the first direction, and a ring-shaped space is formed by the pole piece, the magnet, and the circular groove of the upper plate, and the guide groove may be 5 mm or less.

[0016] In one embodiment, when viewed from the first direction, the second cover portion may have a second cover length extending from the edge of the magnetic field forming portion that is smaller than the depth of the guide groove.

[0017] The present invention provides a method for assembling a speaker, comprising: a magnetic field forming part placement step in which a magnetic field forming part including a lower plate, a magnet, and an upper plate is placed in a mold along a first direction in one embodiment; an insert injection step in which a frame part is formed by insert injection molding with the magnetic field forming part placed in the mold; and an assembly step in which a damper part, a voice coil part, a diaphragm, and an edge part are combined with the frame part; wherein the mold includes an upper mold and a lower mold, and the gap between the upper mold and the lower mold at the position where the lower plate, the magnet, and the upper plate are placed corresponds to the stacking height of the lower plate, the magnet, and the upper plate, and the upper mold or the lower mold includes a column located inside the edge of the magnetic field forming part when viewed from the first direction.

[0018] In one embodiment, the magnetic field forming part has a square shape when viewed from the first direction, the lower plate includes a circular pole piece, the width of the column is 5 mm or less, and the magnet may be a ferrite magnet. Effects of the invention

[0020] The present invention can provide a speaker with low deviation while using a ferrite magnet through the above configuration.

[0021] The present invention can provide a speaker that is easy to manufacture and has small manufacturing deviations, and a method for manufacturing the speaker. Brief explanation of the drawing

[0022] Figure 1 is a cross-sectional perspective view of a speaker. Figure 2 is a schematic diagram showing the assembly of the magnetic field forming part of a speaker. FIG. 3 is an exploded perspective view of a speaker including a ferrite magnet according to an embodiment of the present invention. Figure 4 is a cross-sectional view of the speaker of Figure 3. Fig. 5 is a bottom view of the speaker of Fig. 3. FIG. 6 is an assembly flowchart of a speaker including a ferrite magnet according to an embodiment of the present invention. FIG. 7 is a schematic perspective view of the arrangement step of the magnetic field forming part of FIG. 6. FIG. 8 is a bottom view of a speaker including a ferrite magnet according to another embodiment of the present invention. Figure 9 is a plan view of the magnetic field forming part of the speaker of Figure 8. Specific details for implementing the invention

[0023] Preferred embodiments of the present invention will be described below with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0024] In addition, embodiments of the present invention are provided to more fully explain the present invention to those with average knowledge in the relevant technical field.

[0025] In drawings, the shapes and sizes of elements may be exaggerated for clearer explanation.

[0026] In describing the embodiments of the present invention, if it is determined that a detailed description of known technology related to the present invention may unnecessarily obscure the essence of the present invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, such definitions should be based on the content throughout this specification. The terms used in the detailed description are merely for describing the embodiments of the present invention and should not be limited in any way. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form.

[0027] In this description, expressions such as “include” or “equipped” are intended to refer to certain characteristics, numbers, steps, actions, elements, parts or combinations thereof, and should not be interpreted to exclude the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, parts or combinations thereof other than those described.

[0028] In this specification, terms such as 'top', 'upper', 'upper surface', 'lower', 'lower surface', 'lower side', and 'side' are based on the drawings, and in reality, they may vary depending on the direction in which the elements or components are arranged. In this specification, based on the drawing of FIG. 1, the side where the diaphragm is arranged is referred to as the upper side and the side where the yoke is arranged is referred to as the lower side, but this is not absolute and may vary depending on the direction of arrangement.

[0029] Additionally, throughout the specification, when it is said that one part is 'connected' to another part, this includes not only cases where they are 'directly connected,' but also cases where they are 'indirectly connected' with other elements in between.

[0030] The present invention will be described in detail below through each embodiment or example of the invention. It should be noted that each embodiment or example described in this specification is not limited to a single embodiment or example, but may also be combined with other embodiments or examples. Accordingly, the citation of claims in the patent claims is merely an example of an embodiment, and the technical concept of the present invention should not be interpreted as being limited only to a combination with the cited claims; rather, combinations with various claims are also included within the scope of the technical concept of the present invention.

[0031] FIG. 1 shows a cross-sectional perspective view of a conventional speaker, and FIG. 2 shows a schematic representation of the assembly of the magnetic field forming part of the speaker of FIG. 1.

[0032] The speaker (1) includes: a frame portion (10) forming the outer shape of the speaker (1); a magnetic field forming portion (20) that is partially disposed inside the frame portion (10) and forms a magnetic field; a voice coil portion (30) that is disposed adjacent to the magnetic field forming portion (20) and vibrates in conjunction with the magnetic field forming portion (20) according to an electrical signal; a damper portion (40) that is connected to the voice coil portion (30) and supports the voice coil portion (30); a diaphragm (50) that is connected to the voice coil portion (30) and vibrates together with the voice coil portion (30) to form sound; an edge portion (70) that is located between the frame portion (10) and the diaphragm (50) and enables the vibration of the diaphragm (50) relative to the frame portion (10); and a dust cap (80) that blocks the inflow of foreign matter from the upper part of the voice coil portion (30).

[0033] The magnetic field generating part (20) is fixed to the frame part (10), and when an electric signal is received through the terminal part (35) connected to the voice coil part (30), the voice coil part (30) vibrates within the magnetic field formed by the magnetic field generating part (20) to generate sound.

[0034] The magnetic field forming part (20) includes a magnet (21), an upper plate (22), and a lower plate (23). The magnet (21), the upper plate (22), and the lower plate (23) must be accurately positioned so that a magnetic field centered on the voice coil part (30) is symmetrically formed. Only then can the input signal be used to reproduce the sound intended to be output. If the alignment is off, the sound is generated in a distorted manner, which degrades the performance of the speaker (1).

[0035] The speaker (1) is assembled in the order of placing a lower plate (23) having a circular pole piece (23a), joining the upper plate (22) combined with the magnet (21) and frame part (10) using adhesive, placing the voice coil part (30) and damper part (40), and placing the diaphragm (50). Since the assembly of the speaker (1) is done manually using adhesive, a jig for assembly is used to secure the correct position during the manual process.

[0036] As shown in FIG. 2, to assemble the magnetic field forming part (20), a lower plate (23) is placed on a jig (100) in which a groove (101) is formed, adhesive is applied, a magnet (21) is placed, and then adhesive is applied again and bonded to the upper plate (22). Unlike the upper plate (22) or the lower plate (23), in the case of the magnet (21), particularly a ferrite magnet, shape deviation occurs due to shrinkage and deformation of the ceramic material during the process of compressing and sintering the powder. Therefore, in order to insert the magnet (21) into the jig (100), sufficient clearance must be provided in the groove of the jig (100). In the case of having a circular pole piece (23a), rotation cannot be prevented even if the pole piece is aligned at the center. Therefore, due to the clearance, the position of the magnet (21) is inevitably rotated and misaligned despite using the jig (100), and there is a limitation that the sound quality is degraded as a result.

[0037] In particular, when aligning based on a shape with large dimensions during assembly, the allowable margin dimension must also be set large. When the assembled magnetic field forming part (20) is inserted into the frame part (10), the margin dimension must be set based on the external shape, so the margin dimension becomes large, and consequently, the performance of the speaker being produced is inconsistent. That is, a large difference occurs between the width (lr) of the groove (101) of the jig (100) and the length (lm) of the magnetic field forming part (20), so the magnet (21) can rotate to a certain extent within the jig (100).

[0038] In the present invention, a guide groove formed in a part of the magnetic field forming part (20) is applied to align the magnetic field forming part (20) along with a structure in which the magnetic field forming part (20) is inserted and injected into the frame part (10) after assembly, so that a relatively small clearance dimension for the ferrite magnet may be required. Since the clearance dimension may be small, the positional deviation of the ferrite magnet in the assembled magnetic field forming part (20) is reduced, so the quality of the speaker (1) being manufactured can be provided consistently.

[0039] FIGS. 3 to 5 illustrate a speaker (1) according to an embodiment of the present invention. Specifically, FIG. 3 illustrates an exploded perspective view of a speaker including a ferrite magnet according to an embodiment of the present invention, FIG. 4 illustrates a cross-sectional view of the speaker of FIG. 3, and FIG. 5 illustrates a bottom view of the speaker of FIG. 3.

[0040] The speaker (1) includes: a frame portion (10) forming the outer shape of the speaker (1); a magnetic field forming portion (20) disposed inside the frame portion (10) and forming a magnetic field; a voice coil portion (30) disposed adjacent to the magnetic field forming portion (20) and vibrating in conjunction with the magnetic field forming portion (20) according to an electrical signal; a damper portion (40) connected to the voice coil portion (30) and supporting the voice coil portion (30); a diaphragm (50) connected to the voice coil portion (30) and vibrating together with the voice coil portion (30) to form sound; an edge portion (70) located between the frame portion (10) and the diaphragm (50) and enabling the vibration of the diaphragm (50) relative to the frame portion (10); and a dust cap (80) blocking the inflow of foreign matter from the upper part of the voice coil portion (30).

[0041] The magnetic field forming part (20) is formed by stacking an upper plate (22), a magnet (21), and a lower plate (23), and the direction in which the upper plate (22), the magnet (21), and the lower plate (23) are stacked is called the first direction. FIG. 3 is an exploded perspective view of the speaker (1) disassembled along the first direction. In this embodiment, for convenience of explanation, the side where the diaphragm (50) is placed is called the upper side, and the side where the magnetic field forming part (20) is placed can be called the lower side, but the upper and lower directions may be changed depending on the direction in which the speaker (1) is placed.

[0042] The frame portion (10) forms the outer shape of the speaker (1) and is formed of resin, having a structure in which other components are combined. A terminal portion (35) connected to a voice coil portion (30) is arranged on one side of the frame portion (10), and an external signal is transmitted through the terminal portion (35). The frame portion (10) includes a cover portion that covers the edge of the magnetic field forming portion (20). The cover portion may include a first cover portion (11) that covers the edge of the upper plate (22) and a second cover portion (13) that covers the stepped portion (23b) of the lower plate (23), and also includes a side cover portion (12) that connects the first and second cover portions (11, 13) and covers the side of the magnet (21). The frame portion (10) has a shape that widens as it extends upward from the cover portion surrounding the magnetic field forming portion (20), and is configured so that the damper portion (40) and the diaphragm (50) are connected at the upper side of the magnetic field forming portion (20). The cover portion surrounding the magnetic field forming portion (20) will be explained in detail later.

[0043] The magnetic field forming part (20) includes a magnet (21) that forms a magnetic field, an upper plate (22) disposed on the surface facing the diaphragm (50) from the magnet (21), a lower plate (23) disposed opposite the upper plate (22) with the magnet (21) at the center, and a guide groove (26) extending along the first direction from the magnet (21), the upper plate (22), and the lower plate (23).

[0044] The magnetic field generating part (20) may have a roughly rectangular or square shape when viewed from the first direction, and the corners may be rounded, but are not limited thereto. In addition, in this embodiment, the guide groove (26) is formed on both opposing sides of the square-shaped magnetic field generating part (20), but is not limited thereto and may be formed on all four sides.

[0045] When the square shape of the magnetic field forming part (20) is rectangular, the guide groove (26) may be formed at the center of the short side, and in this case, the reduced portion of the magnet due to the formation of the guide groove (26) may be located at a position further from the center than when it is formed at the center of the long side, thereby reducing the effect of magnetic force reduction.

[0046] When viewed from a first direction, the lower plate (23) includes a pole piece (23a) with a circular cross section protruding toward the magnet (21) from the central upper surface, a stepped portion (23b) surrounding the edge of the lower surface, and a groove (23c) and a guide groove (26) positioned in the center of the lower surface. The pole piece (23a) extends into the circular grooves (21a, 22a) of the magnet (21) and the upper plate (22), and a ring-shaped space (25) is formed between the circular grooves (21a, 22a) and the pole piece (23a), and a part of the voice coil portion (30) is positioned in this ring-shaped space (25). The second cover portion (13) of the frame portion (10) is positioned in the stepped portion (23b), and the second cover portion (13) covers the lower surface of the lower plate (23) to fix the position of the magnetic field forming portion (20). The groove (23c) is positioned on the opposite side of the pole piece (23a) and can be used to position it correctly in the lower mold (110) described later.

[0047] An upper plate (22) has a circular groove (22a) formed in the center, and a guide groove (26) is also formed in the upper plate (22), and the first cover portion (11) is arranged surrounding the upper edge of the upper plate (22). Since the first cover portion (11) is formed to cover the guide groove (26) of the magnetic field forming portion (20), the first cover length (l1) extending from the edge of the magnetic field forming portion (20) of the first cover portion (11) of the upper plate (22) is formed to be longer than the second cover length (l2) extending from the edge of the magnetic field forming portion (20) of the second cover portion (12). In this embodiment, the upper plate (22) does not have a stepped portion formed at the edge, but it is possible to form one if necessary.

[0048] The magnet (21) has a circular groove (21a) formed in the center and a guide groove (26) formed on the edge. In this embodiment, the magnet (21) is a ferrite magnet.

[0049] The guide groove (26) is formed in the lower plate (23), magnet (21), and upper plate (22), penetrates the magnetic field forming part (20) when viewed from a first direction, and is formed at a certain depth (th) from the edge. The guide groove (26) can limit the twisting of the magnet (21) during the manufacturing of the magnetic field forming part (20). The width (lh) of the guide groove (26) may be 1 / 5 or less of the short side length (lm) of the magnetic field forming part (20), and preferably 5 mm or less. In the case of a ferrite magnet, it is manufactured with a tolerance of about 1-3% due to shrinkage and deformation of the ceramic material, but when the width (lh) is 5 mm or less, the assembly deviation is at most about 0.1 mm, so the deterioration of sound quality due to rotation of the magnet can be prevented.

[0050] The shape of the guide groove (26) is connected to the edge surface and the curved surface when viewed from the first direction, and the inner corner is a rounded square shape (see FIG. 7), but is not limited thereto and can have various shapes.

[0051] The voice coil section (30) has a wire wound on a bobbin, and a tinsel wire may be connected to the end of the wire. The tinsel wire is connected to a terminal section (35) that is exposed to the outside of the frame section (10). The voice coil section (30) is configured to be attached to the diaphragm (50) and move together with it, and by moving according to an electronic signal transmitted through the tinsel wire within the magnetic field formed by the magnetic field forming section (20), it vibrates the diaphragm (50) to form sound.

[0052] The damper portion (40) connects the inner surface of the frame portion (10) with the voice coil portion (30) and allows vibration of the voice coil portion (30). The diaphragm (50) is connected to the voice coil portion (30) and moves according to the movement of the voice coil portion (30) to form sound. Since it has a cone shape and can be formed from a paper material, it may also be called cone paper. In this embodiment, it has an elliptical shape when viewed from the first direction, but it is not limited thereto and can have various shapes such as a square or a circle.

[0053] The edge portion (70) connects the diaphragm (50) and the frame portion (10), and supports the diaphragm (50) while allowing it to vibrate relative to the frame portion (10). The edge portion (70) is configured to surround the edge of the diaphragm (50).

[0054] Let us describe the magnetic field forming part (20) and the frame part (10). In this embodiment, the magnetic field forming part (20) is insert injection molded into the frame part (10). That is, the frame part (10) is molded through insert injection while the magnetic field forming part (20) is placed in the mold, and thereby the upper plate (22) of the magnetic field forming part (20) is covered by the first cover part (11) of the frame part (10), the side of the magnetic field forming part (20) is covered by the side cover part (12), and the lower plate (23) is covered by the second cover part (13) of the frame part (10).

[0055] The first and second cover portions (11, 13) cover a certain length from the side edge of the magnetic field forming portion (20), the first cover portion (11) surrounds the edge of the upper plate (22) by a first cover length (l1), and the second cover portion (13) surrounds the stepped portion (23b) formed at the edge of the lower plate (23) by a second cover length (l2). The first cover length (l1) is formed to be larger than the second cover length (l2), and the first cover length (l1) is formed to be larger than the depth (th) of the guide groove (26), so that the guide groove (26) is completely covered by the first cover portion (11). Additionally, the second cover portion (13) includes a cover groove (13a), and the cover groove (13a) is formed at a position corresponding to the guide groove (26). That is, as shown in FIG. 5, when viewed from the bottom, the cover groove (13a) and the guide groove (26) are formed to be connected, so that the first cover part (11) is visible through the cover groove (13a) and the guide groove (26). Therefore, even if the cover groove (13a) and the guide groove (26) are open to the outside, the passage is blocked by the first cover part (11), thereby preventing foreign matter from entering the interior of the speaker (1) and preventing air inside the speaker from leaking out.

[0056] Referring to FIGS. 6 and 7, a method for manufacturing a speaker according to an embodiment of the present invention and a mold used in the manufacturing method are illustrated.

[0057] A method for manufacturing a speaker according to one embodiment of the present invention comprises: a magnetic field forming part placement step (S110) in which a magnetic field forming part (20) including a lower plate (23), a magnet (21), and an upper plate (22) is placed in a mold (110, 120) along a first direction; an insert injection step (S120) in which a frame part (10) is formed by insert injection molding with the magnetic field forming part (20) placed in the mold (110, 120); and an assembly step (S130) in which a damper part (40), a voice coil part (30), a diaphragm (50), and an edge part (70) are combined with the frame part (10).

[0058] The magnetic field forming part placement step (S110) corresponds to the conventional magnetic field forming part manufacturing step. In the present invention, the lower plate (23), magnet (21), and upper plate (22) combined with the frame part (10) are bonded using an adhesive and a jig, but in the present invention, the lower plate (23), magnet (21), and upper plate (22) for insert injection are placed in a mold (110, 120) including a guide column (111), and resin is injected to perform insert injection, thereby simplifying the manufacturing process and improving the alignment of the magnetic field forming part.

[0059] The magnetic field forming part placement step (S110) and the insert injection step (S120) are performed using the same mold, and after the magnetic field forming part is placed in the mold in the magnetic field forming part placement step (S110), the insert injection is performed.

[0060] The above mold (S110, S120) includes an upper mold (120) and a lower mold (110), and the gap between the upper mold (120) and the lower mold (110) at the location where the lower plate (23), magnet (21) and upper plate (22) are placed corresponds to the stacking height of the lower plate (23), magnet (21) and upper plate (22), and the upper mold (120) or the lower mold (110) includes a guide column (111) located inside the edge of the magnetic field forming part (20) when viewed from a first direction. In this embodiment, the guide column (111) is formed in the lower mold (110).

[0061] The magnetic field forming part (20) is square-shaped when viewed from the first direction, and the lower plate (23) includes a circular pole piece (23a), and the magnetic field forming part (20) may have the same shape as the magnetic field forming part of FIGS. 3 to 5.

[0062] The guide column (111) has a shape corresponding to the guide groove (26) and, like the guide groove (26), its width may be 5 mm or less. Since the width of the guide column (111) is formed to be smaller than the width of the magnetic field forming part (20), the parts constituting the magnetic field forming part (20) can be positioned in the correct position without rotating relative to each other. In addition, centering of the ring-shaped space (25) in the circular groove (21a, 22a) is important, and centering of the ring-shaped space (25) is achieved by inserting the ring-shaped column (121) formed in the upper mold into the ring-shaped space (25).

[0063] In this embodiment as well, the magnet (21) may be a ferrite magnet, and as mentioned above, a product tolerance of ±2% is typically applied to all shapes except the thickness due to the characteristics of the product. Accordingly, the tolerance of the larger part of the dimension is bound to increase proportionally. In the present invention, by including a guide column (111) of small dimensions, it is possible to minimize assembly deviation to a maximum of ±0.1mm even with a product tolerance of approximately ±2%, thereby eliminating concerns about performance degradation and interference with the assembly partner due to assembly deviation.

[0064] The thickness (tg) of the guide column (111) has the same length as the depth (th) of the guide groove (26), and as shown in FIGS. 4 and 5, the first cover portion (11) is shorter than the first cover length (l1) extending from the edge of the magnetic field forming portion (20), and the second cover portion (12) is formed to be longer than the second cover length (l2) extending from the edge of the magnetic field forming portion (20), so that the guide groove (26) formed by the guide column (111) does not communicate with the internal space of the speaker.

[0065] FIG. 8 shows a bottom view of a speaker including a ferrite magnet according to another embodiment of the present invention, and FIG. 9 shows a top view of a magnetic field forming part of the speaker of FIG. 8.

[0066] In the case of the embodiments of FIGS. 8 and 9, they are identical to the speakers of FIGS. 3 to 5 except for the magnetic field generating part (20), so the differences will be explained with a focus on the magnetic field generating part (20), and the remaining components will be replaced with the description of the speakers of FIGS. 3 to 5.

[0067] In this embodiment, the magnetic field forming part (20) is formed such that the guide groove (26) is not formed at the center of the side of the square shape when viewed from the first direction, but at the corner of the square shape. Accordingly, in this embodiment, the magnetic field forming part (20) has four guide grooves (26) formed at the four corners.

[0068] The width (lh) of the guide groove (26) may be 1 / 5 or less of the short side length (lm) of the magnetic field forming part (20), and preferably 5 mm or less. In the case of the guide groove (26) formed at the corner, the depth of the guide groove (26) may be formed to be the same length as the width (lh) of the guide groove (26), and, as in the embodiments of FIGS. 3 to 5, the first cover part (11) is shorter than the first cover length (l1) extending from the edge of the magnetic field forming part (20), and the second cover part (12) is formed longer than the second cover length (l2) extending from the edge of the magnetic field forming part (20), so that the guide groove (26) formed by the guide column (111) does not communicate with the internal space of the speaker.

[0069] Although the present invention has been described above with reference to embodiments, the invention is not limited thereto and can be implemented with various modifications. Explanation of the symbols

[0070] 1: Speaker 10: Frame part 20: Magnetic field forming part 21: Magnet 22: Upper plate 23: Lower plate 25: Ring-shaped space 26: Guide groove 30: Voice coil section 40: Damper section 50: Diaphragm 70: Edge 80: Dust cap 110: Lower mold 120: Upper mold

Claims

Claim 1 A speaker comprising: a frame portion forming an outer shape; a magnetic field forming portion inserted and disposed in the frame portion and forming a ring-shaped space; a voice coil portion having at least a portion inserted and disposed in the ring-shaped space; a damper portion connecting the voice coil portion and the frame portion; a diaphragm connected to the voice coil portion; and a terminal portion electrically connected to the voice coil portion and disposed in the frame portion; wherein the magnetic field forming portion includes an upper plate, a magnet, and a lower plate stacked in a first direction, and the magnetic field forming portion includes a plurality of guide grooves extending from the edge in the first direction, and the magnetic field forming portion is insert injection molded into the frame portion, and the frame portion includes a cover portion covering the edge of the magnetic field forming portion in the first direction, and the cover portion includes a cover groove formed at a position corresponding to the guide groove. Claim 2 In claim 1, the magnetic field forming part has a square shape when viewed from the first direction, and the guide groove is formed at the center of two sides facing the magnetic field forming part when viewed from the first direction. Claim 3 In claim 2, the guide groove is a speaker formed at the center of the four sides when viewed from the first direction. Claim 4 In claim 1, the guide groove is a speaker formed at the corner of the magnetic field forming part when viewed from the first direction. Claim 5 delete Claim 6 In claim 1, the cover portion comprises a first cover portion covering a first surface adjacent to the diaphragm in the magnetic field forming portion and a second cover portion covering a second surface facing the first surface, wherein the first cover portion has a first cover length extending from the edge of the magnetic field forming portion that is longer than the depth of the guide groove, and the second cover portion includes the cover groove. Claim 7 In claim 1, the magnetic field forming part has a square shape when viewed from the first direction, the guide groove is formed at the center of two sides facing each other from the magnetic field forming part when viewed from the first direction, the lower plate includes a circular pole piece protruding in the first direction, a ring-shaped space is formed by the pole piece, the magnet, and the circular groove of the upper plate, and the guide groove is 5 mm or less. Claim 8 In claim 6, when viewed from the first direction, the second cover portion is a speaker in which the second cover length extending from the edge of the magnetic field forming portion is smaller than the depth of the guide groove. Claim 9 A method for assembling a speaker comprising: a magnetic field forming part placement step of placing a magnetic field forming part including a lower plate, a magnet, and an upper plate in a mold along a first direction; an insert injection step of forming a frame part by insert injection molding with the magnetic field forming part placed in the mold; and an assembly step of combining a damper part, a voice coil part, a diaphragm, and an edge part with the frame part; wherein the mold includes an upper mold and a lower mold, and the gap between the upper mold and the lower mold at the position where the lower plate, the magnet, and the upper plate are placed corresponds to the stacking height of the lower plate, the magnet, and the upper plate, and the upper mold or the lower mold includes a column located inside the edge of the magnetic field forming part when viewed from the first direction. Claim 10 A method of assembling a speaker according to claim 9, wherein the magnetic field forming part is square in shape when viewed from the first direction, the lower plate includes a circular pole piece, the width of the column is 5 mm or less, and the magnet is a ferrite magnet.

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