JPH0441677Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a small-sized, particularly thin speaker.

[Background technology and its problems]

When designing a small and thin speaker, a major issue is how thin the magnetic circuit can be made. The simplest way to make the magnetic circuit thinner is to reduce the thickness of the bottom of the yoke, but simply reducing the thickness of the bottom of the yoke reduces the cross-sectional area of the magnetic circuit and reduces the magnetic field. This will lead to saturation.

In addition, with conventional thin speakers, it is difficult to mechanically fix the yoke to the frame, and for this reason, most of the methods have been to bond the yoke to the frame using adhesive, but this method is easy to work with. Not only is this extremely poor, but it is also extremely difficult to center the yoke, making it easy to produce defective products due to misalignment of the yoke.

Therefore, the present applicant has proposed a speaker in which the frame and yoke are integrated without adhesive as described above, and the bottom of the frame is effectively used as a part of the bottom of the yoke in terms of magnetic circuitry. It has been proposed earlier.

FIG. 1 is a sectional view showing an integrated structure of a speaker frame and a yoke proposed by the present applicant. In FIG. 1, reference numeral 1 indicates a frame, and the frame 1 is a sheet metal made of a magnetic material such as brass or iron, and is pressed into the shape shown in the figure.
A circular opening 2 is formed in the center of the frame 1. 3 indicates a yoke, which is usually made of silica iron or the like and has a cylindrical shape with a bottom.
A cylindrical protrusion 4 is integrally formed in the center of the bottom surface 3A of the yoke 3. The diameter of this protrusion 4 is approximately equal to the diameter of the opening 2, and the protrusion 4
The peripheral portion 4A of the protrusion 4 is cut into a slightly raised annular shape from the bottom surface 4B of the protrusion 4.

The yoke 3 is a cylindrical bottom part 1 of the frame 1.
inserted into A. The bottom surface portion 1A of the frame 1 is in close contact with the bottom surface of the bottom surface portion 3A of the yoke 3, and the protrusion 4 of the yoke 3 is in contact with the opening 2 of the bottom surface portion 1A of the frame 1.
mated to. The yoke 3 is fixed to the frame 1 by caulking the peripheral portion 4A of the protrusion 4. In other words, as shown in FIG.
The peripheral portion 4A of is caulked by the roll riveting device 5. This roll riveting device 5 is provided with an inclined caulking rod 7 at the tip of a rotary shaft 6 which is rotationally driven by an appropriate drive mechanism, and the caulking rod 7 is rotated by rotation of the rotary shaft 6. The tip of the caulking rod 7 is pressed against the peripheral portion 4A of the protrusion 4 while making the swinging rotation movement. As a result, the peripheral portion 4A of the protrusion 4 is sequentially pressurized and crimped by the tip of the crimping rod 7 along its circular trajectory.

As described above, by making the thickness of the bottom part 3A of the yoke 3 sufficiently thin and bringing the bottom part 1A of the frame 1 into close contact with the bottom part, the bottom part 1A of the frame 1 can be connected to the yoke 3 in terms of the magnetic circuit. Because it is configured to be used effectively as a part of the yoke, the overall thickness of the speaker, which had been limited in the past, can be reduced by the thinner thickness of the bottom of the yoke, making it extremely thin. A thin speaker was realized.

However, fixing the yoke and the frame by the roll riveting method described above requires steps such as processing the yoke into a special shape, which has the problem of increasing the number of steps and man-hours required. Further, when this method is used, there is a drawback that a special device such as a roll riveting device is required.

[Purpose of invention]

This invention aims to reduce the thickness of the magnetic circuit by integrating the yoke and the frame with a simple and inexpensive device, thereby providing a thin speaker.

[Summary of the idea]

This idea consists of a frame made of a magnetic material that has a recessed portion approximately in the center and a first opening provided in the center of the bottom of the recessed portion, and a second opening formed approximately in the center of the flat portion. is inserted into the recess of the frame and fixed to the frame by bending the peripheral edge surrounding the first opening into the second opening so that the inner wall of the first opening of the frame forms a flat surface together with the flat surface. a plate-shaped magnet laminated on a flat surface formed by a flat surface and an inner wall of the yoke; a plate-shaped pole piece laminated on the magnet; and a rising wall of the yoke. This speaker consists of a voice coil placed in the opposing gap between the pole piece and the pole piece, and a diaphragm coupled to the voice coil.

〔Example〕

An embodiment of this invention will be described with reference to the drawings. In order to facilitate understanding of the features of this invention, first, the integrated structure of the frame and yoke will be explained with reference to FIG.

In FIG. 3, numeral 11 indicates a frame, and this frame 11 is made by pressing a sheet metal made of a magnetic material such as brass or iron with a thickness of 0.5 mm into a shape having a recess 11A in the center as shown in the figure. It is. The diameter of this frame 11 is, for example, 50 mm. A circular opening 20 is provided in the center of the frame 11.
is formed. Reference numeral 12 indicates a yoke, and this yoke 12 is made of, for example, silica iron and has a cylindrical shape with a bottom, and the thickness of its flat portion 12A is, for example, 0.7 mm.
This is made thinner than the thickness of the rising wall portion 12B. A circular opening 21 is formed in the center of the flat portion 12A of the yoke 12. The radius of this opening 21 is larger than that of the opening 20 formed in the frame 11 by approximately the thickness of the flat portion 12A of the yoke 12. Therefore, when the yoke 12 is stacked on the frame 11, the peripheral edge surrounding the opening 20 of the frame 11 is
It protrudes inward from the opening 21 of No. 2. The above-described frame 11 and yoke 12 are fixed as follows.

In FIG. 3, 25 and 26 indicate molds for fixing the frame 11 and yoke 12 together. The molds 25 and 26 have planar portions 25A and 26A that face each other, respectively. The mold 25 has a cylindrical protrusion 25B on its flat surface 25A, while the mold 26 has a circular recess 26B on its flat surface 26A. The protrusion 25B and the recess 26B are arranged on the same axis so that they can be inserted and removed, and each diameter is smaller than the diameter of the opening 21 of the yoke 12 and larger than the diameter of the opening 20 of the frame 11. Although not shown, a pressurizing mechanism is provided which moves the molds 25 and 26 in the directions of arrows A and B, and whose pressurizing force can be varied as appropriate.

The frame 11 is stacked between a mold 25 and a mold 26 arranged to face each other by pressing the outer peripheral part of the yoke 12 into the recess of the frame 11.
and a yoke 12 are arranged. At this time, the centers of the openings 20 and 21 of the frame 11 and the yoke 12 and the centers of the molds 25 and 26 are arranged in the same line. By moving the mold 25 and the mold 26 in the directions of arrows A and B, respectively, by the above-mentioned pressurizing mechanism, the protrusion 25B of the mold 25 presses against the opening 20 of the frame 11 and the yoke, as shown in FIG. 12 and is inserted into the recess 26B of the mold 26. Since the pressurizing mechanism is one that can vary the pressurizing force as described above, the mold 2
When the protrusion 25B of No. 5 is fitted into the recess 26B of the mold 26, the pressing force of the flat surfaces of the molds 25 and 26 is set to such an extent that the bottom surfaces of the frame 11 and the yoke 12 are not crushed. Projection 25 of mold 25
When B fits through the opening 20 of the frame 11, the opening 20 formed in the frame 11 is inserted into the mold 25.
Because it is smaller than the diameter of the protrusion 25B of the frame 1
The peripheral edge surrounding the opening 20 of the yoke 12 is bent as shown in FIG. In this manner, the frame 11 and the yoke 12 are fixed together by caulking. Note that the opening 2 formed in the frame 11
The radius of 0 is smaller than the radius of the opening 21 formed in the yoke 12 by approximately the thickness of the flat part 12A of the yoke 12, so as will be described later, the surface on the yoke 12 on which the magnets are stacked is Since the frame 11 is fixed, no unevenness occurs. That is, when the peripheral edge of the opening 20 of the frame 11 is bent into the opening 21 of the yoke 12 and integrated, the inner wall 20A formed by the tip of the bent opening 20 is flat with the upper surface of the flat part 12A of the yoke 12. Form a plane X.

As mentioned above, an example of a speaker according to this invention constituted by the integrated frame 11 and yoke 12 is shown in FIG. A magnet 13 is stacked and fixed on the integrated frame 11 and yoke 12. The magnet 13 is cylindrical and has an opening 22 formed in its center. A pole piece 14 is stacked and fixed on the magnet 13. The pole piece 14 is cylindrical and has an opening 23 formed in its center. An opening 23 formed in this pole piece 14
and an opening 22 formed in the magnet 13 described above.
The diameter of the opening 24 is approximately equal to that of the opening 24 formed in the integrated frame 11 and yoke 12. Therefore, when the magnet 13 and the pole piece 14 are stacked on the integrated frame 11 and yoke 12, the opening 22 and the opening 2
3 and the opening 24 form a through hole. This through hole serves as a path for airflow generated by vibration, and is one of the factors that determines the sound quality of the speaker.

A magnetic gap is formed between the outer peripheral end of the pole piece 14 and the inner peripheral end of the tip of the peripheral part 12B of the yoke 12, and the coil is wound on the peripheral surface of the cylindrical voice coil bobbin 16 within this magnetic gap. A voice coil 15 is provided. This voice coil bobbin 16
The upper end of the diaphragm 17 is attached to the center of the diaphragm 17 . The outer periphery of the diaphragm 17 is attached to the outer periphery of the frame 11 with a paper ring 18. This diaphragm 17 is made of, for example, polyethylene terephthalate film. 19 indicates a cap, and the cap 19 is mounted on the voice coil bobbin 16.

[Application example]

The magnet and pole piece may be disc-shaped instead of ring-shaped.

A structure may be adopted in which a stepped portion is formed in the magnet, and the peripheral edge of the opening of the frame bent by caulking is located within this stepped portion.

[Effect of idea]

According to this invention, since the bottom part of the frame is effectively used as a part of the bottom part of the yoke, the thickness of the bottom part of the yoke can be made sufficiently thin. Therefore, the speaker can be made thinner. In addition, the yoke and frame can be integrated by caulking the periphery of the opening provided in the center of the frame to the periphery surrounding the opening provided in the center of the yoke, so the parallelism of the yoke to the frame and the centering of the yoke can be improved. This is easier and more precise than bonding with adhesives, etc., and does not require any special processing or steps, so the frame and yoke can be integrated with inexpensive equipment. Furthermore, unlike a structure in which the bent end of the frame is in contact with the pole piece, according to this invention, there is no shortening of the magnetic circuit, and the magnetic flux from the magnet can be used efficiently.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views used to explain the previously proposed speaker, and FIGS. 3 and 4 are cross-sectional views used to explain the integrated structure of the frame and yoke in one embodiment of this invention. FIG. 5 is a sectional view of one embodiment of this invention. 11...Frame, 12...Yoke, 12A...
...Flat part, 12B... Rising wall part, 13... Magnet, 14... Pole piece, 15... Voice coil, 17... Vibration plate.

Claims (1)

[Claims for Utility Model Registration] A frame made of a magnetic material that has a recessed portion approximately in the center and a first opening provided in the center of the bottom of the recessed portion, and a second opening provided approximately in the center of the flat portion. a peripheral edge surrounding the first opening is inserted into the recess of the frame so that the inner wall of the first opening of the frame forms a flat surface together with the flat surface; a yoke that is fixed to the frame by being bent inward; a plate-shaped magnet that is laminated on a flat surface formed by the flat surface of the yoke and the inner wall; and a plate-shaped magnet that is laminated on the magnet. A speaker comprising: a plate-shaped pole piece; a voice coil disposed in a gap between the rising wall of the yoke and the pole piece facing each other; and a diaphragm coupled to the voice coil.