JPH10327486A - Loudspeaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an appropriate countermeasure against leakage magnetic flux of a loudspeaker while making the profile thin and ensuring a prescribed vibration area of a diaphragm. SOLUTION: A repulsion magnetic circuit 24 has a center plate 26, a front side magnet 28 and a rear side magnet 30 fixed to both sides of the center plate 26 while the same poles are opposed to each other. Three voice coil mounting holes are made on a diaphragm 32 in a line at an equal interval and the diaphragm 32 is supported to a circumferential wall 18 of a frame 14 via an edge 40 at its circumferential ridge. A voice coil 36 at its inner circumferential side has an annular clearance 38 against the center plate 26 and is fitted to each hole of the diaphragm 32 at an outer circumferential side. An iron plate 48 is placed on an inner face side of the left/right side walls of a cabinet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker in which a bobbin is omitted and a voice coil is directly attached to a diaphragm to achieve a reduction in thickness, and more particularly to a loudspeaker provided with a measure against leakage magnetic flux. is there.

[0002]

2. Description of the Related Art In recent years, with the practical use of thin monitors such as PDPs (plasma display panels), there has been an increasing demand for thinner speakers. The present applicant has omitted the bobbin and attached the outer periphery of the voice coil directly to the diaphragm to reduce the thickness, and provided a plurality of holes for arranging repulsive magnetic circuits in a single diaphragm, A thin speaker in which a repulsion magnetic circuit is arranged in each repulsion magnetic circuit arrangement hole, that is, a multi-point drive type and a predetermined diaphragm area is secured has been filed earlier (not yet published at the time of this application). ).

On the other hand, when a speaker is arranged close to an electric device affected by magnetic flux, it is necessary to take measures against magnetic flux leakage from the speaker. In the conventional speaker, the voice coil is attached to the bobbin, and the cone-shaped diaphragm extends forward from the front end of the bobbin, and the outer peripheral side of the bobbin is vacant. It was easy to take measures against magnetic flux leakage from the speaker.

[0004]

In the above-described thin loudspeaker, the repulsion magnetic circuit is placed at the center and the diaphragm is located at the same position as the center plate of the repulsion magnetic circuit in the front-back direction in order to make it thinner. It is difficult to arrange the magnetic material for magnetic shielding just outside the voice coil. The front magnet is
Although it may be possible to arrange the magnetic shielding magnetic body at a position outside the voice coil in the radiation direction of the repulsion magnetic circuit at the position of the magnet in front of the diaphragm in the axial direction of the repulsion magnetic circuit, In that case, the magnetic material for magnetic shielding becomes a horn, which affects the diffusion of emitted sound.

An object of the present invention is to provide a loudspeaker in which the thickness is reduced and appropriate measures against leakage magnetic flux are taken.

[0006]

A speaker according to the present invention (10)
Has the following (a) to (d). (A) A diaphragm (32) which is provided with a hole for disposing a repulsive magnetic circuit and is supported by a diaphragm support (18) via an edge (40) at a peripheral edge portion. A voice coil (36) attached to the installation hole (c) A plate (26) disposed on the inner peripheral side of the voice coil (36) with a gap (38) between the voice coil (36) and the voice coil (36) And a pair of magnets (28, 30) fixed to both sides of the plate (26) with the same poles facing each other. (D) At least in the axial direction of the repulsion magnetic circuit (24). plate
The magnetic body for magnetic shielding (48) disposed outside the diaphragm support (18) occupying the overlapping range with (26)

The magnetic material for magnetic shielding (48) is a support for the diaphragm.
Even if it is not arranged over the entire circumferential direction of (18),
In particular, it may be arranged only in the direction in which it is desired to avoid the leakage magnetic flux. When the magnetic flux extending radially outward from the plate (26) reaches the magnetic shielding magnetic body (48), it bends, passes through the magnetic shielding magnetic body (48), and passes through the magnetic shielding magnetic body (48). ) Is prevented from leaking outside.

According to another speaker (10) of the present invention, the rear end of the magnetic shielding magnetic body (48) is further provided with a repulsive magnetic circuit (2).
In the axial direction of 4), it reaches rearward beyond the rear end of the repulsion magnetic circuit (24).

The magnetic flux entering the magnetic shielding magnetic body (48) passes through the inside of the magnetic shielding magnetic body (48) and extends in the axial direction of the repulsion magnetic circuit (24) beyond the rear end of the repulsion magnetic circuit (24). And returns to the magnet (30) on the rear side of the repulsion magnetic circuit (24). The result, in particular,
It is possible to reliably suppress the magnetic flux of the rear magnet (30) from going outside the magnetic shielding magnetic body (48).

According to another speaker (10) of the present invention, the diaphragm (32) is provided with a plurality of holes for disposing a repulsive magnetic circuit in a row. A voice coil (36) and a repulsion magnetic circuit (24) are provided corresponding to each repulsion magnetic circuit arrangement hole. The magnetic material for magnetic shielding (48) extends in the direction of arrangement of the holes for disposing the repulsive magnetic circuit.

The speaker (10) has a plurality of repulsive magnetic circuits (2
4) It is longer in the arrangement direction and shorter in the direction perpendicular to the arrangement direction. As a result, of the leakage flux from the speaker (10),
Although the leakage magnetic flux in the short side direction tends to increase, the magnetic material for magnetic shielding (48) is disposed along at least one of the two long sides of the speaker (10), and the speaker ( The magnetic flux that leaks out beyond the magnetic body for magnetic shielding (48) in the short side direction of 10) is blocked and suppressed.

According to another loudspeaker (10) of the present invention, the diaphragm support (18) and the magnetic shielding magnetic body (48) are an integrated product (60) of the same material.

The support for the diaphragm (18) and the magnetic material for magnetic shielding (4
By using 8) as an integrated product (60) of the same material, the labor for assembling the diaphragm support (18) and the magnetic shielding magnetic body (48) can be omitted.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a front view of the speaker 10, and FIG. 2 is a cross-sectional view of the speaker 10 as viewed from the right side.
The cabinet 12 is a storage box for the components of the speaker 10. The dimensions of the outer shape of the cabinet 12 are, for example, about 50 mm in width, about 230 mm in length, and 15 m in depth (depth).
m, and the cabinet 12 is elongated vertically. The slope portion 13 is provided on the front surface of the cabinet 12, has a track shape of a stadium in a front view, and is inclined inward from the outside toward the inside. Frame 14, bottom 16,
Protrudes forward from the periphery of the bottom part 16 and the front face has an edge pasting part 20
And three pole portions 22 arranged at equal intervals on the left-right symmetric line of the frame 14. The upper and lower ends of the frame 14 are provided with raised portions 21 that protrude forward from the edge tension margin 20. The repulsion magnetic circuit 24 is fitted into each pole portion 22 and has a front plate 28 and a rear magnet 30 that are fixed to the center plate 26 in front and rear of the center plate 26 with the same polarity facing the center plate 26 made of a soft magnetic material such as iron. And The diaphragm 32 made of paper has a circumferential contour equal to the track shape of the slope portion 13 and includes a total of three vibrating portions 34. Is a circular hole larger than the outer diameter by a predetermined dimension. Each vibrating part 34 has its front (= front) side aligned on the same plane, its back (= rear) side changed in the front-rear direction, and is thicker at the center and thinner toward the radially outward side. . The rib 39 is provided in a thin portion between the adjacent vibrating portions 34. The cloth edge 40 has the same contour as the track shape of the slope portion 13, is fixed to the peripheral edge portion of the diaphragm 32 and the edge pasting portion 20 on the inner and outer circumferences, respectively, and has a curved shape (FIG. ) To perform the function as a damper. The holding plate 42 extends along the left and right center lines of the diaphragm 32, is fixed to the raised portion 21 of the frame 14 at the upper and lower ends by screws 44, and is
And is fixed to the top of the pole portion 22 by. The rectangular iron plate 48 (in FIG. 2, the iron plate 48 is indicated by a hatched area)
It is fixed to the inner surface of the left and right side walls of the cabinet 12, and extends vertically over the range of both screws 44, and the center plate
It extends from the front end of 26 to the rear end of the repulsion magnetic circuit 24 to the inner surface of the back wall of the cabinet 12.

FIG. 3 is a schematic sectional view of the speaker 10 in the width direction, and FIG. 4 is a magnetic flux diagram in FIG. The front magnet 28 and the rear magnet 30 have their N poles facing each other. The iron plate 48 as the magnetic material for magnetic shielding reaches the front end of the center plate 26 at the front end (upper end in FIG. 3) of the repulsion magnetic circuit 24 in the axial direction. The magnetic flux emitted from the front magnet 28 and the rear magnet 30 travels in the center plate 26 in the surface direction of the center plate 26 and exits radially outward from the peripheral surface of the center plate 26. When the magnetic flux substantially along the plane of the center plate 26 reaches the iron plate 48, the magnetic flux is refracted so as to pass through the iron plate 48, and is suppressed from going outside beyond the iron plate 48. The magnetic flux relating to the rear magnet 30 passes through the inside of the iron plate 48, reaches sufficiently rearward from the rear end of the rear magnet 30, and returns to the rear magnet 30. The magnetic flux relating to the front magnet 28 is such that the magnetic flux that has exited from the center plate 26 along the surface direction of the center plate 26, that is, the magnetic flux that may reach the farthest in the radiation direction of the repulsion magnetic circuit 24 reaches the iron plate 48. Then, by passing through the front end of the iron plate 48, the direction is appropriately changed from the radial outside to the inside. Thus, the magnetic flux heading toward the iron plate 48 is suppressed from going outside beyond the iron plate 48.

FIG. 5 is a sectional view of a structure obtained by partially changing the structure of FIG. The iron plate 48 and the frame 62 are integrated as a part of an integrated iron product 60 as a magnetic material. The frame 62 includes the bottom 16, the peripheral wall 18, and the edge pasting portion 20 of the frame 14 in FIG. 2. The pole 64 is separate from the frame 62, and the bottom is fixed to the frame 62. The integration of the iron plate 48 and the frame 62 by the integrated iron product 60 saves the labor of assembling.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a speaker viewed from a right side surface.

FIG. 2 is a cross-sectional view of the speaker as viewed from the right side.

FIG. 3 is a schematic cross-sectional view in the width direction of the speaker.

FIG. 4 is a magnetic flux diagram in FIG.

FIG. 5 is a sectional view of a structure obtained by partially changing the structure of FIG. 4;

[Explanation of symbols]

 Reference Signs List 10 speaker 18 peripheral wall (diaphragm support) 24 repulsive magnetic circuit 26 center plate (plate) 28 front magnet (magnet) 30 rear magnet (magnet) 32 diaphragm 36 voice coil 38 annular gap (gap) 40 edge 48 Iron plate (magnetic material for magnetic shielding) 60 Iron integrally molded product (integral product)

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI H04R 9/06 H04R 9/06 Z

Claims (4)

[Claims] 1. (a) A diaphragm (32) provided with a hole for disposing a repulsive magnetic circuit and supported on a diaphragm support (18) via an edge (40) at a peripheral edge, and (b) an outer periphery A voice coil (36) whose side is attached to the repulsion magnetic circuit arrangement hole,
(C) A plate (2) arranged on the inner peripheral side of the voice coil (36) with a gap (38) between the voice coil (36) and the voice coil (36).
6) and a pair of magnets (28, 30) fixed to both sides of the plate (26) with the same poles facing each other.
4) and (d) a magnetic shield disposed outside the diaphragm support (18) so as to occupy at least an overlapping area with the plate (26) in the axial direction of the repulsion magnetic circuit (24). Magnetic material (4
8) A speaker comprising: 2. The rear end of the magnetic shielding magnetic body (48) extends rearward beyond the rear end of the repulsion magnetic circuit (24) in the axial direction of the repulsion magnetic circuit (24). Claim 1
The described speaker. 3. The vibrating plate (32) includes a plurality of the repulsion magnetic circuit arrangement holes in a row, and the voice coil (36) and the repulsion magnetic circuit correspond to each of the repulsion magnetic circuit arrangement holes. Circuit (2
The speaker according to claim 1, wherein 4) is provided, and the magnetic body for magnetic shielding (48) extends in an arrangement direction of the holes for disposing the repulsive magnetic circuit. 4. The vibration plate support (18) and the magnetic shielding magnetic body (48) are an integrated product (60) of the same material. The described speaker.