JP5724767B2 - Outer magnet type magnetic circuit unit for speaker and manufacturing method thereof - Google Patents

Description

  The present invention relates to a speaker outer magnetic type magnetic circuit unit and a method for manufacturing the same.

  Speakers using magnets are broadly divided into internal magnetic speakers and external magnetic speakers. Each speaker has a basic configuration including a magnetic circuit having a magnetic gap in which a voice coil is disposed, a vibrating body driven by an electromagnetic force generated by energizing the voice coil, and a frame for instructing them (for example, Patent Document 1). , 2).

  The external magnet type speaker has a magnet arranged on the outer peripheral side of the magnetic gap into which the voice coil is inserted. As shown in the longitudinal sectional view of FIG. The vibration unit 120 is supported by a frame 110 and an outer magnet type magnetic circuit unit 130.

  The vibration unit 120 includes a voice coil bobbin 121, a voice coil 122 provided on the outer periphery of the voice coil bobbin 121, a damper 123 that supports the voice coil bobbin 121 so as to be able to vibrate, and a diaphragm attached to the upper part of the voice coil bobbin 121. 124, an edge portion 125 attached to the outer peripheral edge of the diaphragm 124, and a center cap 126 attached to the central portion of the diaphragm 124. In the vibration unit 120, the outer peripheral edge of the damper 123 is attached to the frame 110, and the outer peripheral edge of the edge portion 125 is attached to the frame 110, so that the diaphragm 124 can vibrate together with the voice coil bobbin 121. Supported by the frame 110.

  The outer magnet type magnetic circuit unit 130 includes a yoke 131, a ring-shaped magnet 132, and a ring-shaped top plate 133.

  The yoke 131 has a center pole 135 formed at the center of the bottom plate 134. The ring-shaped magnet 132 is concentric with the center pole 135 and is sandwiched and fixed by the bottom plate 134 and the top plate 133. A magnetic gap 136 is formed between the outer peripheral surface on the upper end side of the center pole 135 and the peripheral surface of the central opening of the top plate 133.

  In the outer magnetic type magnetic circuit unit 130, the upper part of the top plate 133 is fixed to the frame 110, and the voice coil 122 of the vibration unit 120 supported by the top plate 133 is placed in the magnetic gap part 136. Has been placed.

  Further, the inner magnet type speaker has a magnet arranged on the inner peripheral side of the magnetic gap into which the voice coil is inserted, and an example of the structure is shown in the longitudinal sectional view of FIG. 220 includes a vibration unit 120 supported by a frame 110 and an inner magnet type magnetic circuit unit 230.

  In the inner magnet type magnetic circuit unit 230, a columnar (or cylindrical) magnet 232 is housed in a yoke 231 having a space inside. The yoke 231 has an upper end surface fixed to the frame 110 and an opening at the center. A plate 233 attached and fixed to the upper end of the magnet 232 is located in the opening. Further, the voice coil 122 of the vibration unit 120 is inserted through the opening, and the lower end side of the voice coil 122 is positioned so as to contain the plate 233. The frame 110 is attached with a vibration unit 120 having a structure similar to that of an external magnetic speaker.

  By the way, in any of the outer magnet type speaker and the inner magnet type speaker, when the current flowing through the voice coil is the same, the speaker output becomes larger as the magnetic circuit configuration has a magnetic gap with a larger magnetic field.

  In an external magnet type speaker where the magnet is arranged on the outer periphery side of the magnetic gap, the voice coil is arranged inside the magnet, so there is no restriction on the size of the magnet due to the size of the voice coil. The magnetic field of the magnetic gap can be increased. Conventionally, a low-magnetization but inexpensive ferrite magnet has been used in a magnetic circuit of an external-magnet-type speaker in which the area of the magnet can be increased.

  On the other hand, in an internal magnet type speaker in which a magnet is arranged on the inner peripheral side of the magnetic gap, the area of the magnet is limited by the size of the voice coil surrounding the outer peripheral side of the magnet. Limits arise. Conventionally, in an internal magnet type speaker, a magnetic gap of a large magnetic field using a magnet having a strong magnetic force such as an alnico magnet, a rare earth magnet, that is, a Sm—Co magnet, or a neodymium magnet (ie, Nd—Fe—B magnet). To achieve a compact and high-powered speaker.

  Whether the magnetic circuit configuration is an internal magnetic type or an external magnetic type is appropriately selected depending on the use and conditions of the speaker.

JP 2008-99106 A JP 2011-151716 A

  By the way, as means for increasing the magnetic gap magnetic field of the external magnet type speaker, there are a method of reducing the gap of the magnetic circuit and a method of using a rare earth magnet having a large magnetic force in addition to increasing the magnet as described above.

  Conventionally, the top plate, bottom plate, and magnet that make up the magnetic circuit of an external-magnet speaker are mostly fixed using an adhesive. However, the magnetic gap is determined by the processing accuracy of the magnet and the bonding accuracy of each component. Is larger than that required for driving the voice coil, which hinders the magnetic field in the magnetic gap portion from being reduced. In particular, when a ferrite sintered magnet or a rare earth sintered magnet is used, the processing accuracy is about ± 0.1, and when combined with the adhesion accuracy, the original required gap of about +0.1 to 0.3 is required.

  When a rare earth magnet is used in an external magnet type speaker, the magnet is exposed on the outer peripheral surface of the speaker, so that rusting occurs depending on the surrounding environment, which causes a reduction in speaker performance and malfunction.

  In order to solve these problems, a magnetic circuit configuration for increasing the accuracy of the magnetic gap portion and a magnetic circuit configuration that hardly causes rust even when a rare earth magnet is used are required.

  Accordingly, an object of the present invention is to provide an external magnetic circuit for a speaker that has a magnetic gap portion with high accuracy and high magnetic field, which is unlikely to cause rusting even when a rare earth magnet is used, in view of the conventional problems as described above. It is to provide a unit and its manufacturing method.

  Other objects of the present invention and specific advantages obtained by the present invention will become more apparent from the description of embodiments described below.

The present invention is an external magnetic type magnetic circuit unit for a speaker, comprising a yoke having a center pole formed at the center of a ring-shaped bottom plate, a ring-shaped magnet portion surrounding the center pole, and the center pole. A top plate having a central opening peripheral surface that forms a magnetic gap portion with the upper end side outer peripheral surface of the center pole. The ring-shaped magnet portion is covered with an integrally formed resin part on the inner peripheral side and the outer peripheral side, and a space surrounded by the top plate, the yoke, and the resin part is filled with a rare earth magnet material. resin material made ring-shaped magnet which is injection molded, the resin component containing an oxide-based magnet material by Characterized in that it is configured.

In the outer magnetic type magnetic circuit unit for a speaker according to the present invention, the resin component may be formed by injection molding.

  Moreover, in the outer magnetic type magnetic circuit unit for a speaker according to the present invention, the resin component is formed by connecting resin portions arranged on the inner and outer circumferences of the ring-shaped magnet via one or more rims. be able to.

The present invention provides a yoke having a center pole formed in the center of a ring-shaped bottom plate, a ring-shaped magnet portion surrounding the center pole, a ring shape surrounding the center pole, and the magnet portion being the bottom A top plate having a central opening peripheral surface that is sandwiched between and fixed to a plate and forms a magnetic gap portion with an upper peripheral surface of the center pole. Out of a loudspeaker composed of a magnet material, consisting of a ring-shaped magnet whose inner and outer peripheral sides are covered with an integrally formed resin part, the resin part being made of a resin material containing an oxide magnet material. A method of manufacturing a magnetic type magnetic circuit unit, comprising: a yoke, a resin component, and an outer magnetic type magnetic circuit unit for a speaker. The top plate is set in an injection mold, and a rare earth magnet material is filled into the space surrounded by the top plate, yoke, and resin parts through the gate hole formed in the top plate, and a ring magnet Is formed by injection molding to manufacture an outer magnetic type magnetic circuit unit for a speaker in which the top plate, yoke, resin component and ring magnet are integrated.

  The speaker external magnetic type magnetic circuit unit according to the present invention includes a ring-shaped magnet portion having a structure in which at least the outer peripheral side of a ring-shaped magnet made of a rare earth magnet material is covered with a resin component. The ring magnet made of rare earth magnet material is not exposed on the outer peripheral surface of the magnetic circuit unit, and rusting of the ring magnet can be reduced, and the resin parts are made of oxide magnet material By doing so, the magnetic field of a magnetic gap part can be enlarged, the usage-amount of an expensive rare earth magnet material can be suppressed, and a required magnetic characteristic can be acquired.

  In the present invention, a magnetic circuit unit with high accuracy and high magnetic field can be provided by forming these components by injection molding.

  That is, in the external magnetic type magnetic circuit unit for a speaker according to the present invention, one or both of the resin component and the ring magnet are formed by injection molding, and the resin component is disposed on the inner and outer circumferences of the ring magnet. Since the resin portions to be connected are connected via one or more rims, the magnetic gap of the speaker outer magnet type magnetic circuit unit can be formed with high accuracy.

  Furthermore, according to the present invention, the yoke, the resin component, and the top plate constituting the speaker outer magnet type magnetic circuit unit are set in an injection mold, and the gate hole formed in the top plate is inserted through the gate hole. The above-mentioned top plate, yoke, resin component and ring magnet are integrated by filling a space surrounded by the top plate, yoke and resin component with a rare earth magnet material and forming a ring magnet by injection molding. An external magnetic type magnetic circuit unit for a speaker can be manufactured.

  Therefore, according to the present invention, it is possible to provide an outer magnetic type magnetic circuit unit for a speaker which is less likely to rust even when a rare earth magnet is used, and which has a magnetic gap portion with high accuracy and high magnetic field, and a method for manufacturing the same. it can.

It is a longitudinal cross-sectional view of the external magnet type speaker to which the present invention is applied. It is a disassembled perspective view of the outer-magnet-type magnetic circuit unit for speakers with which the said outer-magnet-type speaker was equipped. It is a figure which shows typically an example of the manufacturing method of the resin component which comprises the said outer-magnet-type magnetic circuit unit for speakers. It is a figure which shows typically an example of the manufacturing method of the yoke which comprises the said outer-magnet-type magnetic circuit unit for speakers. It is a figure which shows typically an example of the manufacturing method of the top plate which comprises the said outer-magnet-type magnetic circuit unit for speakers. It is a figure which shows typically an example of the manufacturing method of the said outer-magnet-type magnetic circuit unit for speakers. It is a longitudinal cross-sectional view which shows typically the various comparative examples of the structure of the said outer-magnet-type magnetic circuit unit for speakers. It is a longitudinal cross-sectional view which shows the structure of a general internal magnet type speaker. It is a longitudinal cross-sectional view which shows the structure of a general external magnet type speaker.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The present invention is applied to an outer magnet type speaker 100 having a structure as shown in FIGS. 1 and 2, for example.

  This outer magnet type speaker 100 includes a vibration unit 20 supported by a frame 10 and an outer magnet type magnetic circuit unit 30 for speakers.

  FIG. 1 is a longitudinal sectional view of the outer magnet type speaker 100, and FIG. 2 is an exploded perspective view of the outer magnet type magnetic circuit unit 30 for the speaker provided in the outer magnet type speaker 100.

  The vibration unit 20 includes a voice coil bobbin 21, a voice coil 22 provided on the outer periphery of the voice coil bobbin 21, a damper 23 that supports the voice coil bobbin 21 so as to be able to vibrate, and a diaphragm attached to the upper part of the voice coil bobbin 21. 24, an edge portion 25 attached to the outer peripheral edge of the diaphragm 24, and a center cap 26 attached to the center portion of the diaphragm 24. In the vibration unit 20, the outer peripheral edge of the damper 23 is attached to the frame 10, and the outer peripheral edge of the edge portion 25 is attached to the frame 10, so that the diaphragm 24 can vibrate together with the voice coil bobbin 21. It is supported by the frame 10.

  The speaker outer magnet type magnetic circuit unit 30 includes a yoke 31, a ring-shaped magnet portion 32, and a ring-shaped top plate 33.

  The yoke 31 has a center pole 35 formed at the center of a ring-shaped bottom plate 34. The ring-shaped magnet portion 32 is concentric with the center pole 35 and is sandwiched and fixed by the ring-shaped bottom plate 34 and the top plate 33. A magnetic gap portion 36 is formed between the outer peripheral surface on the upper end side of the center pole 35 and the peripheral surface of the central opening of the top plate 33.

  In the outer magnetic type magnetic circuit unit 30 for speaker, the upper part of the top plate 33 is fixed to the frame 10, and the voice coil 22 of the vibration unit 20 supported by the top plate 33 is connected to the magnetic gap part 36. Is placed inside.

  The ring-shaped magnet portion 32 in the speaker external-magnet-type magnetic circuit unit 30 provided in the external-magnet-type speaker 100 includes a ring-shaped magnet 38 whose outer peripheral side is covered with a resin component 37. Is made of a resin material containing an oxide magnet material, and the ring-shaped magnet 38 is made of a rare earth magnet material containing either Nd (neodymium) or Sm (samarium).

  As shown in the exploded perspective view of FIG. 2, the speaker outer magnet type magnetic circuit unit 30 includes a resin part 37 in the speaker outer magnet type magnetic circuit unit 30 that covers the outer peripheral side of the ring magnet 38. 37A and the resin part 37B which covers the inner peripheral side are connected via a rim 37C.

  The resin part 37 may be composed of different parts on the inner diameter side and the outer diameter side. For example, as shown in FIG. The accuracy can be improved.

  Further, the yoke 31 and the top plate 33 of the speaker outer magnet type magnetic circuit unit 30 are formed by pressing magnetic materials 31A and 33A, respectively, as schematically shown in FIGS. 4 and 5. Is formed.

  The ring-shaped magnet portion 32 in the speaker outer magnet type magnetic circuit unit 30 has one or both of the resin component 37 and the ring-shaped magnet 38 formed by injection molding. The component 37 is formed in advance by injection molding, and the ring-shaped magnet 38 is formed by injection molding when the speaker outer magnet type magnetic circuit unit 30 is manufactured.

  Here, FIG. 6 schematically shows an example of a method for manufacturing the speaker outer magnet type magnetic circuit unit 30.

  That is, when manufacturing the speaker outer magnet type magnetic circuit unit 30, as shown in FIG. 6A, first, in the first step, the yoke constituting the speaker outer magnet type magnetic circuit unit 30 is formed. 31, the top plate 33, and the resin component 37 are set in the injection mold 50 with the spacer 36A inserted so as to secure the magnetic gap portion 36.

  The top plate 33 is provided with a gate hole 331 for injection molding of the ring-shaped magnet 38. As shown in FIG. 6B, in the next second step, the gate hole 331 of the top plate 33 is provided. A ring-shaped magnet 38 is injection molded by filling a space surrounded by the yoke 31, the top plate 33 and the resin component 37 with a rare earth magnet material containing either Nd (neodymium) or Sm (samarium). It is formed by.

  In this way, by filling the space surrounded by the yoke 31, the top plate 33 and the resin component 37 with the rare earth magnet material and forming the ring-shaped magnet 38 by injection molding, the yoke 31, the top plate 33, the resin part 37 and the ring-shaped magnet 38 are integrated, and as shown in FIG. 6C, in the next third step, the resin mold 37 is removed from the injection mold 50 and the spacer 36A is removed to remove the spacer 36A. A speaker outer magnet type magnetic circuit unit 30 having a magnetic gap portion 36 formed by a gap of a predetermined distance between the outer peripheral surface of the upper end side of the center pole 35 and the peripheral surface of the central opening of the top plate 33 is manufactured. .

  Here, the resin component 37 may be a general resin such as nylon (polyamide fiber), PPS (polyphenylene sulfide), PP (polypropylene), etc., as long as it can withstand the temperature at the time of injection of the ring magnet 38. By using a magnet material in which resin and magnetic powder are mixed, the magnetic field of the magnetic gap portion can be increased as compared with the case where only resin is used.

  The magnet material used for the resin component 37 is preferably, for example, a ferrite-based injection-molded magnet material. Furthermore, the magnetic field of the magnetic gap portion 36 can be further increased by using an anisotropic ferrite-based injection-molded magnet material.

  In the speaker outer magnet type magnetic circuit unit 30 of this example, the resin component 37 is formed in advance by injection molding, and the ring magnet 38 is ejected when the speaker outer magnet type magnetic circuit unit 30 is manufactured. The resin component 37 may be formed by injection molding when the speaker outer magnetic type magnetic circuit unit 30 is manufactured. One of the resin component 37 and the ring-shaped magnet 38 may be formed by a method other than injection molding. For example, the resin part 37 may be produced by cutting, for example, but the injection molding method is suitable in view of productivity, cost, ease of production, and the like.

  The outer magnetic type magnetic circuit unit 30 for a speaker includes a ring-shaped magnet portion 32 having a structure in which at least the outer peripheral side of a ring-shaped magnet 38 made of a rare earth magnet material is covered with a resin component 37. Can reduce rusting. Moreover, the magnetic field of the magnetic gap part 36 can be made larger by comprising the said resin component 37 with an oxide type magnet material. Furthermore, the magnetic circuit unit 30 with high accuracy and high magnetic field can be provided by producing these parts by injection molding.

  Here, an external magnetic type magnetic circuit unit 30 for a speaker in which only the outer peripheral surface of a ring-shaped magnet 38 made of a rare earth magnet material is covered with a resin component 37 made of an oxide-based magnet material is shown in FIG. Samples S1 to S6 having various structures shown in A) to (F) were prepared, and their magnetic properties and the like were measured. The results shown in Table 1 were obtained.

  A sample S1 shown in FIG. 7A is an external magnetic type magnetic circuit unit 130 for a speaker having a conventional structure in which the outer peripheral surface of the ring-shaped magnet 132 is not covered with a resin component.

  In the sample S2 shown in FIG. 7B, a ring-shaped magnet 38 having a shape in which the outer peripheral surface of the ring-shaped magnet 132 in the outer magnetic type magnetic circuit unit 130 for a speaker having the above-described conventional structure is scraped by 1 mm to secure a space for resin parts. Is an external magnetic type magnetic circuit unit 130A for speakers.

  In the sample S3 shown in FIG. 7C, the outer peripheral surface of the ring-shaped magnet 38 in the speaker external magnetic type magnetic circuit unit 136A of the sample S2 is covered with a resin component 37 having a thickness of 1 mm made of an oxide-based magnet material. This is an external magnetic type magnetic circuit unit 30A for a speaker having the above structure.

  In the sample S4 shown in FIG. 7D, the outer peripheral surface of the top plate 33 in the outer magnet type magnetic circuit unit 30A for the speaker of the sample S3 is also shaved so This is an external magnetic type magnetic circuit unit for speaker 30 </ b> B having a structure covered with a resin part 37.

  An outer magnetic type magnetic circuit unit for speaker 30C of sample S5 shown in FIG. 7E is obtained by setting the thickness of the resin component 37 in the outer magnetic type magnetic circuit unit for speaker 30B of sample S4 to 3 mm.

  A speaker outer magnetic type magnetic circuit unit 30D of sample S6 shown in FIG. 7F is obtained by setting the thickness of the resin component 37 in the speaker outer magnetic type magnetic circuit unit 30B of sample S4 to 2 mm. The rare earth magnet materials in Table 1 were all bonded magnet materials (Wellmax-S5B-18M) manufactured by Sumitomo Metal Mining Co., Ltd .. This material is a material with a maximum magnetic energy product (BH) max of 140 kJ / m3 (18MGOe), and other rare earth injection bonded magnet materials can also be used, but the same shape because the properties are inferior to the above materials In this case, the magnetic force 1 and the magnetic force 2 are reduced.

  As shown in Table 1, the outer peripheral surface of the ring-shaped magnet 132 in the sample S2 shown in FIG. In the external magnetic type magnetic circuit unit for speaker 130A having a structure that secures a space, the outer surface of the ring-shaped magnet is cut off, so that it occurs in the magnetic gap portion 136 than in the external magnetic type magnetic circuit unit for speaker 130 having a conventional structure. The magnetic force to be weakened. Like the samples S3 to S6 shown in FIGS. 7C to 7F, the outer peripheral surface of the ring-shaped magnet 38 in the outer magnetic type magnetic circuit unit 130A for the speaker of the sample S2 is covered with the resin component 37. In the speaker outer magnetic type magnetic circuit units 30A, 30B, and 300C, the magnetic force generated in the magnetic gap portion 36 and the leakage magnetic flux can be reduced as compared with the speaker outer magnetic type magnetic circuit unit 130A of the sample S2. it can. The resin component 37 is made of an oxide magnet material having a residual magnetic flux density of 2.0 kG, a coercive force of 1.6 kOe, and a specific gravity of 3.

  Therefore, the speaker external magnetic type magnetic circuit unit 30 having the above-described configuration includes the ring-shaped magnet portion 32 having a structure in which at least the outer peripheral side of the ring-shaped magnet 38 made of the rare earth magnet material is covered with the resin component 37. As a result, the ring magnet 32 is not exposed to the outer peripheral surface of the speaker outer magnet type magnetic circuit unit 30, so that rusting of the ring magnet 38 can be reduced and the resin component 37 is oxidized. By using a material-based magnet material, the magnetic force generated in the magnetic gap portion 36 can be increased, the leakage magnetic flux can be reduced, the amount of expensive rare earth magnet material used can be suppressed, and the necessary magnetic characteristics can be obtained. be able to. Furthermore, by producing these parts by injection molding, it is possible to provide a high-accuracy and high-magnetic field outer magnetic type magnetic circuit unit 30 for speakers.

  10 frames, 20 vibration units, 21 voice coil bobbins, 22 voice coils, 23 dampers, 24 diaphragms, 25 edge portions, 26 center caps, 30, 30A, 30B, 30C, 30D speaker external magnetic circuit units, 31 yokes , 32 Magnet part, 33 Top plate, 34 Bottom plate, 35 Center pole, 36 Magnetic gap part, 37 Resin part, 37A, 37B Resin part, 37C Rim, 38 Ring magnet, 100 External magnet type speaker

Claims (4)

A yoke in which a center pole is formed at the center of the ring-shaped bottom plate;
A ring-shaped magnet surrounding the center pole;
A ring-shaped surrounding the center pole, the magnet unit is being sandwiched and fixed between the bottom plate has a central opening the circumferential surface forming the magnetic gap portion between the upper end side outer peripheral surface of the center pole With a top plate,
The ring-shaped magnet part is covered with a rare earth magnet material in the space surrounded by the top plate, the yoke and the resin part, with the inner and outer sides covered with an integrally formed resin part. An external magnetic type magnetic circuit unit for a speaker comprising a molded ring-shaped magnet, wherein the resin component is made of a resin material containing an oxide-based magnet material. The speaker outer magnet type magnetic circuit unit according to claim 1, wherein the resin component is formed by injection molding.   The said resin component connects the resin part arrange | positioned at the inner and outer periphery of the said ring-shaped magnet via one or more rim | limbs, The any one of Claim 1 or Claim 2 characterized by the above-mentioned. Outer magnetic type magnetic circuit unit for speaker. A yoke in which a center pole is formed at the center of a ring-shaped bottom plate, a ring-shaped magnet portion surrounding the center pole, and a ring shape surrounding the center pole, the magnet portion being between the bottom plate And a top plate having a central opening peripheral surface that forms a magnetic gap portion between the center pole and the upper peripheral surface of the center pole, and the ring-shaped magnet portion is made of a rare earth magnet material. An external magnetic type magnetic circuit for a speaker comprising a ring-shaped magnet whose inner peripheral side and outer peripheral side are covered with an integrally formed resin part, wherein the resin part is made of a resin material containing an oxide-based magnet material A unit manufacturing method comprising:
Set the yoke, resin parts and top plate constituting the outer magnetic type magnetic circuit unit for the speaker in the injection mold,
The top plate is formed by injection molding by filling a rare earth magnet material into a space surrounded by the top plate, yoke, and resin parts through a gate hole formed in the top plate. A method of manufacturing an external magnetic type magnetic circuit unit for speakers, comprising: manufacturing an external magnetic type magnetic circuit unit in which a yoke, a resin component, and a ring magnet are integrated.

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