JP2009296160A - Speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and thin speaker that makes the most of characteristics of a plastic magnet that can be easily machined in a desired shape and has high mass productivity. <P>SOLUTION: The speaker 1 has: a magnetic circuit 3; a vibration system 4 having a diaphragm 22 attached to a voice coil 21; and a frame 2 for supporting the magnetic circuit 3 and the vibration system 4. In this case, the voice coil 21 is disposed in a magnet gap 17. The magnetic circuit 3 is composed of a plastic magnet 16 having a T-shaped section and a yoke 10 continuously provided at the bottom side and on the periphery of the plastic magnet 16, the number of components of the magnetic circuit conventionally having a three-piece structure is reduced, thus improving the mass productivity of the compact and thin speaker. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a small and thin speaker used for a mobile phone or the like.

  Conventionally, a speaker using a plastic magnet in a magnetic circuit (dynamic type speaker) is known, for example, from Patent Document 1. However, regarding the component configuration and assembly of the magnetic circuit, it was the same as a speaker using a general metal magnet (ferrite, alnico, rare earth, etc.). Regardless of the type of magnet, the magnetic circuit was assembled by adhering the magnet, yoke and pole piece.

JP 2000-32589 A

  The conventional speaker has a problem that the influence of the adhesive used for assembling the magnetic circuit is so great that it is difficult to increase the mass productivity.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a small and thin speaker having high mass productivity by making use of the characteristics of a plastic magnet that can be easily processed into a desired shape.

  To achieve the above object, the present invention provides a speaker comprising a magnetic circuit, a vibration system having a diaphragm attached to a voice coil, and a frame that supports the magnetic circuit and the vibration system, and the voice coil is disposed in a magnetic gap. The magnetic circuit is composed of a plastic magnet having a T-shaped cross section and a yoke provided continuously on the bottom side and the periphery of the plastic magnet, and the magnet itself has the role of a pole piece. Compared to the conventional magnetic circuit of the structure, using a magnet with a larger volume and increasing the driving force of the voice coil, the two-piece structure of the magnetic circuit that was the conventional three-piece structure, that is, the number of parts To reduce.

  In the present invention, it is preferable that the top surface of the plastic magnet is formed as a concave surface and the central portion of the diaphragm is formed in an inverted dome shape.

  In the present invention, a cylindrical portion raised by burring from a yoke on the bottom side of the plastic magnet and a through hole through which the cylindrical portion penetrates the central portion of the plastic magnet are provided, and the plastic magnet is connected to the cylindrical portion. It is preferable to combine with the yoke by crushing the tip of the yoke.

  According to the present invention, the magnetic circuit is composed of a plastic magnet having a T-shaped cross section and a yoke continuously provided on the bottom side and the periphery of the plastic magnet. The reduction can increase the mass productivity of small and thin speakers.

  In the present invention, the top surface of the plastic magnet is formed as a concave surface, and the central portion of the diaphragm is formed in an inverted dome shape, so that a sufficient amplitude of the vibration system is ensured and the acoustic performance is not deteriorated. Further thinning of the thin speaker can be realized.

  In the present invention, a cylindrical portion raised by burring from a yoke on the bottom side of the plastic magnet and a through hole through which the cylindrical portion penetrates the central portion of the plastic magnet are provided, and the plastic magnet is connected to the cylindrical portion. By crushing the tip portion of the coil, it is coupled to the yoke, so that it is not necessary to use an adhesive for assembling the magnetic circuit, and the mass productivity of a small and thin speaker can be further enhanced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a speaker according to an embodiment of the present invention, and FIG. 2 is a plan view of a speaker diaphragm according to an embodiment of the present invention made transparent.

  A speaker 1 shown in FIGS. 1 and 2 includes a yoke-integrated frame 2 made of a magnetic material, a magnetic circuit 3, and a vibration system 4.

  The frame 2 is formed in a low-bottomed cylindrical shape, and has a circular bottom plate 5 and an outer wall 6 rising from the outer peripheral edge of the bottom plate 5. A horizontal step surface 7 is provided on the outer wall 6, and the upper surface of the outer wall 6 is formed with a larger diameter than the lower portion by the step surface 7.

  From the bottom plate 5, a yoke side wall 8, which is an inner wall facing the lower portion of the outer wall 6 with a predetermined gap, is raised, and the yoke side wall 8 and a circular shape formed at the center of the bottom plate 5 inside the yoke side wall 8 are formed. The yoke bottom plate 9 forms a bottomed cylindrical yoke 10 that is lower than the frame 2.

  A pair of lead wire outlets 11 for notching the yoke side wall 8 to the lower end are provided at two left and right sides of the yoke side wall 8, and a pair of circles for inserting lead wire forming jigs into the bottom plate 5 on the bottom side of the lead wire extraction position. A pair of rear sound holes 13 having a substantially semicircular arc shape are provided in the bottom plate 5 on the bottom side of the bottom plate 5 between the outer wall 6 and the yoke side wall 8 other than the lead wire drawing position. Provided. The upper back sound hole 13 in FIG. 2 continuously opens from the bottom plate 5 to the lower portion of the outer wall 6 and the stepped surface 7.

  A substantially semicircular arc-shaped insulating terminal plate 14 whose inner peripheral edge is in contact with the yoke side wall 8 is fixed to the back side of the stepped surface 7 opened by the upper back sound hole 13 in FIG. A pair of external connection terminals (not shown) are attached to the back side of the speaker 1 and a pair of lead wire contact pad portions 15 electrically connected to the external connection terminals are exposed and formed on both end surfaces of the terminal plate 14. The lead wire contact pad portion 15 is exposed in the frame 2 through the back sound hole 13 on the upper side.

  The magnetic circuit 3 includes a plastic magnet 16 and a yoke 10.

  The plastic magnet 16 is formed in a columnar shape having an outer diameter that is substantially the same height as the yoke side wall 8 and slightly smaller than the inner diameter of the yoke side wall 8, and is disposed concentrically on the yoke bottom plate 9. The upper outer peripheral surface of the plastic magnet 16 is opposed to the upper inner peripheral surface with a magnetic gap 17 therebetween.

  Here, taking advantage of the characteristics of the plastic magnet 16 that can be easily processed into a desired shape, the plastic magnet 16 is molded in a T-shaped cross section so that the upper part has a larger diameter than the lower part. Thereby, the upper part of the plastic magnet 16 is brought closer to the yoke side wall 8 than the lower part, so that the magnetic flux is concentrated in the magnetic gap 17. That is, the upper part of the plastic magnet 16 serves as a pole piece, and a larger volume magnet is used in a space-saving manner as compared with the conventional magnetic circuit of the three-piece structure, while increasing the driving force of the voice coil 21 described later, A conventional two-piece magnetic circuit having a three-piece structure, that is, the number of parts is reduced.

  The top surface (upper surface) of the plastic magnet 16 is not a flat surface but a reverse dome-shaped concave surface 18 in order to realize further thinning of the speaker 1.

  Further, in order to connect the plastic magnet 16 and the yoke 10 without using an adhesive, a circular through hole 19 is formed in the central portion of the plastic magnet 16 while passing through a circular through hole 19 in the center portion of the yoke bottom plate 9 by a burring process. When the cylindrical tube portion 20 is raised and the plastic magnet 16 is attached to the yoke 10, the cylindrical portion 20 is fitted into the through hole 19 from the lower side, and the tip portion of the cylindrical portion 20 is formed on the concave surface 18 of the plastic magnet 16. The plastic magnet 16 and the yoke 10 are combined and integrated by projecting upward at the center (deepest part) and crushing the tip of the cylindrical part 20.

  The vibration system 4 includes a voice coil 21 formed by winding a conductive wire around a cylindrical voice coil bobbin made of a metal or plastic film, and a metal or plastic film, which is concentrically attached to the upper portion of the voice coil 21. It is composed of a round diaphragm 22.

  Here, the diaphragm 22 is formed not in the shape of a dome that swells upward but in the shape of an inverted dome that swells downward from the central portion inside the position where the voice coil 21 is attached, in order to realize further thinning of the speaker 1.

  Then, the stepped surface 7 of the outer wall 6 on the outer side of the frame 2 is connected to the rear surface of the outer peripheral edge of the annular edge 24 around the reverse dome 23 of the diaphragm 22 via the diaphragm ring 25 having an L-shaped cross section. The voice coil 21 is disposed in the magnetic gap 17 of the magnetic circuit 3 so as to be movable up and down.

  Lead wires 26 drawn out from the winding start end and winding end end of the voice coil 21 are drawn out from the lead drawing outlet 11 to the outside of the yoke 10 and inserted into the lead drawing position through the circular hole 12 from the lower side of the frame 2. It is hooked by a round bar-shaped forming jig, bent into a substantially U shape (forming), guided to the lead wire contact pad portion 15 to be connected, and the leading end of the lead wire 26 is contacted with the lead wire to be connected by spot welding. It is connected to the pad unit 15.

  In the speaker 1 configured as described above, when an audio signal is input from the external circuit to the voice coil 21 through the pair of external connection terminals, the magnetic field generated in the magnetic circuit 3 and the current flowing in the voice coil 21 are mutually. As a result, the voice coil 21 vibrates up and down, and the surrounding air vibrates up and down in conjunction with it, and the surrounding air is vibrated to produce sound.

  At this time, the magnetic circuit 3 is composed of the plastic magnet 16 having a T-shaped cross section and the yoke 10 continuously provided on the bottom side and the periphery of the plastic magnet 16. The reduction can increase the mass productivity of small and thin speakers.

  In addition, since the top surface of the plastic magnet 16 is formed in the concave surface 18 and the central portion of the diaphragm 22 is formed in an inverted dome shape, a sufficient amplitude of the vibration system 4 is ensured, and the small size without deteriorating the acoustic performance.・ Thin speakers can be made even thinner.

  Furthermore, a cylindrical portion 20 raised by burring from the yoke 10 on the bottom side of the plastic magnet 16 and a through hole 19 through which the cylindrical portion 20 penetrates the central portion of the plastic magnet 16 are provided, and the plastic magnet 16 is connected to the cylindrical portion. Since the tip of 20 is crushed and coupled to the yoke 10, it is not necessary to use an adhesive for assembling the magnetic circuit 3, and the mass productivity of a small and thin speaker can be further enhanced.

  In the present embodiment, one embodiment of the present invention has been described with the round speaker 1, but a square speaker may be used. The present invention is not limited to the present embodiment, and various modifications can be made without departing from the spirit of the present invention.

Sectional drawing of the speaker concerning one embodiment of this invention The top view of the state which transparentized the diaphragm of the speaker concerning one embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Speaker 2 Frame 3 Magnetic circuit 4 Vibration system 10 Yoke 16 Plastic magnet 17 Magnetic gap 18 Concave surface 19 Through-hole 20 Cylindrical part 21 Voice coil 22 Diaphragm 23 Reverse dome part

Claims (3)

  A speaker comprising a magnetic circuit, a vibration system having a diaphragm attached to a voice coil, and a frame that supports the magnetic circuit and the vibration system, wherein the voice coil is arranged in a magnetic gap. A speaker comprising a T-shaped plastic magnet and a yoke provided continuously on and around the bottom of the plastic magnet.   The speaker according to claim 1, wherein the top surface of the plastic magnet is formed as a concave surface, and the central portion of the diaphragm is formed in an inverted dome shape.   A cylindrical portion raised by burring from the yoke on the bottom side of the plastic magnet and a through hole through which the cylindrical portion penetrates the central portion of the plastic magnet are provided, and the plastic magnet is connected to the tip portion of the cylindrical portion. The speaker according to claim 2, wherein the speaker is combined with the yoke by crushing.

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