JP2010239594A - Magnetic circuit for speaker and speaker employing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic circuit for speaker, improved in quality, wherein performance and efficiency can be improved in spite of cost reduction, and a magnet constituting the magnetic circuit is surely held between a top plate and a bottom plate, thereby eliminating the risk of deviating the arrangement of the magnet. <P>SOLUTION: The magnetic circuit for speaker comprises a pole with which a bottom plate part is formed integrally, a top plate, an annular magnet, a plate magnet and a plurality of connecting members. The bottom plate part, the top plate and the annular magnet comprise fixture inserting holes. Each connecting member is comprised of a hollow tubular member to be inserted through the fixture inserting hole of the annular magnet, and a fixture to be inserted into the tubular member. The annular magnet and the plate magnet are concentrically placed on the bottom plate part, the annular magnet and the plate magnet are held between the top plate and the bottom plate part, and the fixture connects the top plate and the bottom plate part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a speaker magnetic circuit and an electrodynamic speaker using the same.

  A conventional electrodynamic speaker includes a magnetic circuit of a multi-ferrite magnet, the bottom plate of a pole following a circular magnet, and a magnetic circuit in which the outer peripheral edge of the plate has a form like a “petal” There is something. Ferrite magnets may be rare earth magnets, some of which attempt to increase the performance and efficiency of their magnetic circuits, while simultaneously reducing costs and improving readability. (Patent Document 1)

  In another conventional electrodynamic speaker, a bolt that penetrates up and down the magnetic circuit communicates with a top plate, a single annular magnet, and a bottom plate to form a magnetic circuit. (Patent Document 2)

European Patent Application No. 1381252 JP-A-57-4696

  However, in the conventional electrodynamic speaker, when the adhesive strength between the bottom plate and the magnet, the top plate and the magnet, or the magnets is insufficient, they may be peeled off or the arrangement may be shifted. Therefore, it had one aspect lacking in reliability from the viewpoint of product quality assurance.

  According to the present invention, although the magnetic circuit has high performance and high efficiency at a low cost, the top plate and the bottom plate can securely hold the magnet constituting the magnetic circuit, and there is a possibility that the magnet arrangement may be shifted. The object is to provide a magnetic circuit for a speaker that has no quality and is excellent in quality.

The magnetic circuit for a speaker of the present invention has a pole formed integrally with a bottom plate part,
A top plate, an annular magnet, a flat plate magnet, and a plurality of connecting members are provided, a bottom plate portion, a top plate, and an annular magnet are provided with fixture insertion holes, and the connecting member is used to fix the bottom plate portion. It is composed of a hollow cylindrical member that is inserted into the fixture insertion hole and the fixture insertion hole of the annular magnet, and a fixture that is inserted into the cylindrical member, and the annular magnet and the flat plate magnet are concentrically mounted on the bottom plate portion. The top plate and the bottom plate portion sandwich the annular magnet and the flat plate magnet, and the fixture connects the top plate and the bottom plate portion.

  Preferably, in the speaker magnetic circuit of the present invention, concentric circular magnets and flat magnets are alternately placed in the circumferential direction.

  Preferably, in the speaker magnetic circuit according to the present invention, either the annular magnet or the flat magnet is stacked on a plurality of stages and placed on the bottom plate portion.

  Moreover, the speaker of this invention is equipped with said magnetic circuit for speakers.

  The method for manufacturing a magnetic circuit for a speaker according to the present invention includes a step of placing an annular magnet and a flat plate magnet on a bottom plate portion of a pole, and a hollow cylindrical member is inserted into a fixture insertion hole of the annular magnet. And a step of connecting the top plate and the bottom plate portion.

  Hereinafter, the operation of the present invention will be described.

  A magnetic circuit for a speaker according to the present invention includes a pole integrally formed with a bottom plate portion, a top plate, an annular magnet, a flat plate magnet, and a plurality of connecting members. The bottom plate portion, the top plate portion, The annular magnet is an outer magnet type magnetic circuit configured to include a fixture insertion hole. The annular magnet and the flat plate magnet are placed on the bottom plate portion, and the top plate and the bottom plate portion sandwich the annular magnet and the flat plate magnet.

  The connecting member includes a fixing member insertion hole in the bottom plate portion, a hollow cylindrical member that is inserted into the fixing tool insertion hole of the annular magnet, and a fixing tool. Since the cylindrical member communicates with the fixture insertion hole of the bottom plate portion and the fixture insertion hole of the annular magnet, the cylindrical member determines the position where the annular magnet is disposed on the bottom plate portion. Therefore, since it becomes easy to arrange the annular magnet and the flat magnet on the circular bottom plate portion at equal intervals in a concentric manner, variation in the completed quality of the magnetic circuit can be reduced and excellent. Playback audio quality can be ensured.

  Since the fixture passes through the cylindrical member inserted through the fixture insertion hole of the bottom plate portion and the fixture insertion hole of the annular magnet, and connects the top plate and the bottom plate portion, the fixture is The inner diameter side end face of the annular magnet is not cut. Therefore, since the magnetic circuit can be configured without affecting the magnetic flux density generated by the magnet, it is possible to supply a speaker magnetic circuit with excellent reproduction sound quality.

  The annular magnet and the flat magnet are, for example, small circular rare earth magnets and can be procured at a relatively low cost. The rare earth magnet has a strong holding force and can generate a high magnetic flux density. Further, these magnets can be arranged concentrically on the bottom plate portion of the pole to constitute a large magnetic circuit. Therefore, even in the case of a large magnetic circuit, it is possible to provide a speaker magnetic circuit with high efficiency and excellent reproduction sound quality at low cost.

  The speaker magnetic circuit according to the present invention and the speaker using the speaker magnetic circuit can be manufactured at low cost even when a large magnetic circuit is configured, and the speaker magnetic circuit has high performance and high efficiency. A circuit can be provided. Furthermore, even if the magnet is fixed with a fixing tool, it does not cause a problem such as generation of dust in the magnetic circuit, so that it is possible to provide an electrodynamic speaker with excellent reproduction sound quality.

It is an exploded view explaining the magnetic circuit 1 for speakers of this invention.

It is the side view and sectional drawing explaining the magnetic circuit 1 for speakers of this invention.

It is a graph which shows the magnetic flux density distribution of the magnetic circuit 1 for speakers of this invention, and the magnetic circuits 10 and 20 for speakers as a comparative example.

FIG. 10 is an exploded view illustrating Comparative Example 10.

FIG. 10 is an exploded view illustrating Comparative Example 20.

Bottom plate part 2
Paul 3
Top plate 4
Annular magnet 5
Flat magnet 6
Connecting member 7
Fixing tool insertion hole 21, 41, 51
Step 22
Screw hole 23
Cylindrical member 71
Flathead screw 72

  Hereinafter, although the magnetic circuit for speakers according to preferred embodiments of the present invention will be described, the present invention is not limited to these embodiments.

  1 and 2 are diagrams for explaining a speaker magnetic circuit 1 according to a preferred embodiment of the present invention. FIG. 1 is an exploded view of a speaker magnetic circuit 1 according to the present invention. FIG. 2 is a side view of the speaker magnetic circuit 1 and a cross-sectional view taken along the line OA at the cross-sectional position passing from the center O through the fixture insertion hole. For the convenience of illustration in FIG. 2, a view in which the countersunk screws 72 are not attached is shown.

  The speaker magnetic circuit 1 of the present embodiment includes a pole 3 integrally formed with a bottom plate portion 2, a substantially annular top plate 4, and a small circular magnet sandwiched between the top plate 4 and the bottom plate portion 2. 5, a small circular plate magnet 6, and a plurality of connecting members 7. The bottom plate portion 2, the top plate 4, and the annular magnet 5 each have a fixture insertion hole. The connecting member 7 includes a fixing member insertion hole 51 of the annular magnet 5, a hollow cylindrical member 71 that is inserted into the fixing member insertion hole 21 illustrated in FIG. 2B of the bottom plate portion, and a fixing tool. . The fixture in the present embodiment is a countersunk screw 72.

  The pole 3 and the top plate 4 are made of soft iron, and the annular magnet 5 and the flat magnet 6 are neodymium magnets. The annular magnet 5 and the flat magnet 6 may be a rare earth magnet having a high holding force and capable of generating a high magnetic flux density, and may be a samarium-cobalt magnet. The cylinder member 71 and the countersunk screw 72 which comprise the connection member 7 are comprised with the material of a nonmagnetic body, and are comprised with stainless steel in a present Example.

  The bottom plate portion 2 formed integrally with the pole 3 is a flat portion formed in a circle around the outer periphery of the center pole, and has a width of about 25.8 mm. The bottom plate portion 2 is formed with a fixture insertion hole 21 having a diameter of 8.0 mm. The fixture insertion hole 21 is formed by forming a step portion 22 with which the cylindrical member 71 abuts and a screw hole 23 into which a flat head screw 72 is screwed. The step portion 22 has a depth of 3.0 mm from the plane of the bottom plate portion 2, and the screw hole 23 has a depth of 8.0 mm from the plane of the step portion 22. The screw hole 23 is a hole that does not penetrate the bottom plate portion 2, but may be a through hole. In the present embodiment, since the countersunk screw 72 is used in the screw hole 23, a screw groove is formed.

  The cylindrical member 71 constituting the connecting member 7 is erected by the cylindrical member 71 being inserted into the fixture insertion hole 21 of the bottom plate portion 2 and contacting the step portion 22. The cylinder member has a height of 15.0 mm, an outer diameter of 8.0 mm, and a fixture insertion hole 73 having an inner diameter of 4.5 mm. Since the depth of the stepped portion 22 is 3.0 mm, the cylindrical member 71 has a height of 12.0 mm on the plane of the bottom plate portion 2 and stands upright.

  The annular magnet 5 is placed on the bottom plate portion 2 so that the fixture insertion hole 51 of the annular magnet 5 and the fixture insertion hole 21 of the bottom plate portion 2 communicate with each other. Therefore, the cylindrical member 71 communicates with the fixture insertion hole 51 of the annular magnet 5 and the fixture insertion hole 21 of the bottom plate portion. The annular magnet 5 has a diameter of 24.0 mm and a thickness of 3.0 mm, and the inner diameter of the fixture insertion hole 51 is 8.0 mm. Since the cylindrical member 71 stands upright at a height of 12.0 mm on the bottom plate portion 2, by stacking four annular magnets 5, the height of the cylindrical member 71 and the height of the four annular magnets 5 overlapped with each other. Is the same. In this embodiment, the annular magnet 5 is placed on the bottom plate portion 2 and the tubular member 71 is communicated. However, the tubular member 71 is inserted into the bottom plate portion 2 and the annular magnet 5 is inserted into the upright tubular member 71. And may be placed.

  The flat magnets 6 are arranged between the annular magnets so as to be concentric with the annular magnet 5. The flat magnet 6 has dimensions of a diameter of 24.0 mm and a thickness of 6.0 mm. Since the thickness of the flat magnet 6 is twice the thickness of the annular magnet 5, if the two flat magnets 6 are stacked and placed, the height of the four circular magnets 5 and the height of the flat magnet 6 are increased. Sato becomes the same. The flat magnet 6 is fixed to the bottom plate portion with an adhesive. Further, the stacked flat magnets are also fixed by an adhesive.

  On the bottom plate portion 2, five sets of annular magnets 5 and five sets of flat plate magnets 6 are alternately arranged concentrically. Here, the diameter of the bottom plate portion is about 110.0 mm, and a relatively large magnetic circuit can be configured. The top plate 4 is placed from the upper part where the annular magnets 5 and the flat magnets 6 are alternately arranged concentrically. The top plate 4 is mounted so that the fixture insertion hole 41 of the top plate 4, the fixture insertion hole 51 of the annular magnet 5 through which the cylindrical member 71 is inserted, and the fixture insertion hole 21 of the bottom plate portion 2 communicate with each other. Placed.

  From the upper part of the top plate 4, the countersunk screw 72 is inserted into the fixture insertion hole 41 of the top plate, the fixture insertion hole 51 of the annular magnet 5 through which the cylindrical member 71 is inserted, and the fixture insertion hole 21 of the bottom plate portion 2. Communicate. Since the countersunk screw 72 is screwed into the screw hole 23 formed in the lower part of the fixture insertion hole 21, the top plate 4 and the bottom plate part 2 firmly hold the annular magnet 5 and the flat plate magnet 6. Therefore, the annular magnet 5 and the flat magnet 6 are less likely to be displaced even if a strong horizontal force is applied to the magnetic circuit. In this embodiment, the countersunk screw 72 is a countersunk head screw having an M4 head and a length of 30 mm.

  An electrodynamic speaker can be constituted by the speaker magnetic circuit of this embodiment, at least the speaker diaphragm, the voice coil bobbin connected to the speaker diaphragm, and the voice coil wound around the voice coil bobbin. it can.

  FIG. 3 shows magnetic flux density distribution graphs of the speaker magnetic circuit 1 and speaker magnetic circuits 10 and 20 as comparative examples described later. The speaker magnetic circuit 1 of the present embodiment has a magnetic flux density of about 1.51 [T] at the maximum. On the other hand, the loudspeaker magnetic circuit of Comparative Example 2 composed entirely of the flat magnet 6 described later has a magnetic flux density of about 1.56 [T] at the maximum. The magnetic circuit for a speaker of Example 1 has a magnetic flux density of about 1.45 [T] at the maximum. Therefore, the magnetic circuit for a speaker according to the present invention has a magnetic flux density of only about 3.2% and a high magnetic flux compared to the magnetic circuit for a speaker of Comparative Example 2, although the annular magnet 5 is used. It is possible to provide a magnetic circuit for a speaker that can generate density and has a good quality and a good balance in which the magnet is not easily separated from the magnetic circuit.

  FIG. 4 is a diagram for explaining a speaker magnetic circuit 10 as a first comparative example. The speaker magnetic circuit 10 of the comparative example is a magnetic circuit constituted only by the annular magnet 6 instead of the flat magnet 6 of the speaker magnetic circuit 1 of the foregoing embodiment. Accordingly, common structures, dimensions, and structures unnecessary for description are partially omitted.

  The speaker magnetic circuit 10 is configured by arranging four sets of four annular magnets 5 on the bottom plate portion 2 at equal intervals in a concentric manner. The bottom plate portion 2 includes ten fixture insertion holes (not shown), and the fixture insertion holes of the bottom plate portion 2 communicate with the fixture insertion holes 51 of the annular magnet 5. The cylindrical member 71 is inserted into the fixture insertion hole of the bottom plate portion 2 and the fixture insertion hole 51 of the annular magnet 5, and the top plate 4 is placed on the upper portion of the annular magnet 5. The top plate 4 includes ten fixture insertion holes 41. From the top of the top plate 4, a flat head screw 72, a fixture insertion hole 41 of the top plate 4, a fixture insertion hole 51 of the annular magnet 5 through which the tubular member is inserted, and a fixture insertion hole of the bottom plate portion 2 The top plate 4 and the bottom plate portion 2 are fixed to each other.

  From the magnetic flux density distribution graph of FIG. 3, since all the magnets of the speaker magnetic circuit 10 of the comparative example 1 are configured using the annular magnet 5, the magnetic flux density is larger than that of the speaker magnetic circuit 1 of the embodiment. Can't get.

  FIG. 5 is a diagram for explaining a speaker magnetic circuit 20 as a second comparative example. The speaker magnetic circuit 20 of the comparative example 2 is a magnetic circuit configured only by the flat magnet 6 instead of the annular magnet 5 of the speaker magnetic circuit 1 of the above-described embodiment. Accordingly, common structures, dimensions, and structures unnecessary for description are partially omitted.

    The speaker magnetic circuit 20 is configured by arranging ten sets of two stacked flat magnets 6 on the bottom plate portion 2 at equal intervals in a concentric manner. Since the arrangement position of the flat magnet 6 is not determined in the upper part of the bottom plate portion 2, it is difficult to arrange the flat magnets 6 in a concentric manner or at equal intervals. The flat magnet 6 is fixed to the bottom plate portion 2 with an adhesive.

  From the magnetic flux density distribution graph of FIG. 3, since all the magnets of the speaker magnetic circuit 20 of the comparative example 2 are configured using the flat magnet 6, the magnetic flux density is larger than that of the speaker magnetic circuit 1 of the embodiment. Can be obtained. However, the bottom plate portion 2 and the flat magnet 6, the flat magnets 6 or the flat magnet 6 and the top plate 4 are fixed by an adhesive. If the adhesive strength is insufficient or the adhesive is deteriorated or the like is likely to be peeled off, the magnetic circuit for a speaker is applied to the reliability of quality.

  As described above, according to the present invention, in the speaker magnetic circuit, the annular magnet 5 and the flat magnet 6 are placed on the upper portion of the bottom plate portion 2, and the cylindrical member 71 is connected to the fixture insertion hole 51 of the annular magnet 5. The bottom plate portion 2 communicates with the fixture insertion hole 21, the top plate 4 is placed on the top of the magnet, and the countersunk screws 72 pass through the fixture insertion hole 41 of the top plate 4 and the fixture insertion of the annular magnet 5. It is inserted into the fixture insertion hole 73 of the cylindrical member 71 inserted into the hole 51 and the fixture insertion hole 21 of the bottom plate portion 2 and screwed into the screw hole 23 formed in the fixture insertion hole 21 of the bottom plate portion 2. As a result, the top plate 4 and the bottom plate portion 2 are connected to each other, so that the magnet of the magnetic circuit is not peeled off or the arrangement is not shifted. It is possible to provide a use magnetic circuit.

  Since the magnetic circuit for a speaker according to the present invention can be configured regardless of whether the magnetic circuit is large or small, an electrodynamic speaker and headphone provided with a magnetic circuit using a plurality of magnets. The present invention can also be applied to other acoustic transducers such as a microphone.

Claims (5)

A pole with an integrated bottom plate,
A top plate, an annular magnet, a flat plate magnet, and a plurality of connecting members;
The bottom plate portion, the top plate, and the annular magnet include a fixture insertion hole,
The connecting member is composed of a hollow cylindrical member that is inserted into the fixture insertion hole of the bottom plate portion and the fixture insertion hole of the annular magnet, and a fixture that is inserted into the cylindrical member,
The annular magnet and the flat plate magnet are placed concentrically on the bottom plate portion,
The top plate and the bottom plate portion sandwich the annular magnet and the flat plate magnet,
The fixture connects the top plate and the bottom plate portion;
Magnetic circuit for speakers. The annular magnets placed concentrically and the plate magnets are alternately placed in the circumferential direction.
The magnetic circuit for a speaker according to claim 1. Either the annular magnet or the flat plate magnet is stacked in a plurality of stages and placed on the bottom plate portion,
The speaker magnetic circuit according to claim 1 or 2.   A speaker comprising the speaker magnetic circuit according to claim 1. A step of placing an annular magnet and a flat plate magnet on the bottom plate portion of the pole;
A step of inserting a hollow cylindrical member into the fixing hole of the annular magnet;
Connecting the top plate and the bottom plate portion,
A method of manufacturing a magnetic circuit for a speaker.

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