Yoke of speaker

speaker

Technical field

The present invention relates to a speaker used in a portable communication device such as a mobile phone.

Background technique

A speaker with a magnetic circuit composed of a yoke and a magnet 3 and integrated with a frame is disclosed in, for example, Japanese Patent Laid-Open No. 4-362900.

Fig. 4 is a cross-sectional view of a conventional speaker. The bottomed cylindrical yoke 101 is made of a magnetic material such as iron. The frame 102 made of resin is fixed to the outer periphery of the yoke 101 by pressing and inserting. The magnet 103 is adhesively bonded to the bottom surface of the yoke 101 with a certain distance from the inner surface of the side wall of the yoke 101. The pole plate 104 is adhesively bonded to the upper surface of the magnet 103, and a magnetic gap 104a is formed between the pole plate 104 and the inner surface 101a of the yoke 101. The diaphragm 105 is formed of a resin sheet. The voice coil 106 is located in the magnetic gap 104a, and one end of the voice coil 106 is glued and fixed to the lower part of the diaphragm 105.

The voice coil 106 is formed by winding and heating an insulating-coated coil wire with a hot melt layer formed on the surface. The coil ends 106a at both ends of the voice coil 106 are led out from between the diaphragm 105 and the yoke 101, and are welded and connected to the ends of the lead-out terminals 107 integrally formed on the frame 102.

According to the above configuration, a sound signal is input to the voice coil 106 from an external signal sound source via the lead-out terminal 107, and the coil 106 and the diaphragm 105 are vibrated to produce sound.

If the conventional speaker described above is thinned and increased in output for use in portable communication devices such as mobile phones, the coil end 106a drawn out from between the diaphragm 105 and the yoke 101 may be caused by vibration when the speaker is driven. When the diaphragm 105 or the yoke 101 is in contact, a strange sound is generated. Therefore, a certain amount of space must be left between the diaphragm 105 and the yoke 101, and therefore, the thickness reduction of the conventional speaker is limited.

Summary of the invention

The speaker of the present invention is provided with: a cylindrical yoke having a bottom surface and a side wall, and a notch is formed on the side wall; a magnet arranged on the bottom surface of the yoke at a distance from the side wall of the yoke; A pole plate that forms a magnetic gap between the magnet and the inner surface of the side wall; a frame arranged on the outer periphery of the yoke; a vibrating membrane combined with the outer periphery and the frame; a coil with one end connected to the vibrating membrane and located in the magnetic gap A voice coil formed by winding a wire; and a lead-out terminal provided on the frame and connected to the end of the coil wire drawn from the voice coil. The cut portion is located on the part of the side wall of the forehead corresponding to the end of the coil wire.

The speaker can be made thinner because the interval between the diaphragm and the yoke can be reduced.

Description of the drawings

Fig. 1 is a cross-sectional view of a speaker according to an embodiment of the present invention.

Fig. 2 is a plan view of a voice coil and a yoke of the speaker of the embodiment.

Fig. 3 is a plan view of the coil and another yoke of the embodiment.

Fig. 4 is a cross-sectional view of a conventional speaker.

detailed description

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 coil and a yoke that are the main parts of the speaker.

As shown in Fig. 1, the bottomed cylindrical yoke is made of a magnetic material such as iron. The frame 2 made of resin is fixed to the outer circumference of the yoke by pressing or inserting. The magnet 3 and the inner surface 1 a of the side wall of the yoke 1 are adhesively bonded to the bottom surface of the yoke 1 with a certain interval. The pole plate 4 is adhesively bonded to the upper surface of the magnet 3, and a magnetic gap 4a is formed between the pole plate 4 and the inner surface 1a of the yoke 1. The diaphragm 5 is formed of a resin sheet. The voice coil 6 is located in the magnetic gap 4a, and one end of the voice coil 6 is glued and fixed to the lower part of the diaphragm 5.

One end of the voice coil 6 is glued and fixed to the lower part of the diaphragm 5, and the other end is located in the magnetic gap 4a. The voice coil 6 is formed by winding and heating an insulating-coated coil wire with a hot melt layer formed on the surface.

The lead portions 6a at the coil ends of the coil wire of the voice coil 6 are led out in the tangential direction during winding, pass through the diaphragm 5 and the yoke 1, and are respectively connected to a pair of lead terminals 7 provided on the frame 2 by welding or the like. Electric connection.

In the embodiment, on the cylindrical wall of the yoke 1, the vicinity of the part below the lead part 6a of the coil end drawn in the tangential direction of the voice coil 6, that is, the lead part 6a of the coil end, is seen from above. The opposite part is provided with a notch 1c. The lead portion 6a at the end of the coil is located in and above the cutout portion 1c when the speaker is driven to vibrate in the vertical direction. Therefore, even if the interval between the diaphragm 5 and the yoke 1 is small, the interval between the lead portion 6a at the end of the coil and the yoke 1 can be secured by the cutout portion 1c, so the speaker can be made thinner.

Fig. 3 is a plan view of a voice coil and another yoke of the speaker of the embodiment. The yoke 1b is further provided with a notch 1d.

Because of the magnetic flux leaking from the notch portion 1c, the magnetic flux crossing the voice coil 6 is unbalanced. In the case where the notch 1c is large and the magnetic flux imbalance is large, the diaphragm 5 will fluctuate when vibrating, and it will collide with the yoke 1 and produce a strange sound. In extreme cases, vibration may occur. The film 5 is broken.

The cut-out portion 1d partially reduces the magnetic flux as in the cut-out portion 1c, and eliminates the imbalance of the magnetic flux in the entire yoke 1b. Therefore, the above-mentioned problem is not caused.

In addition, in the speaker in the embodiment, the yokes 1 and 1b are cylindrical, but the same effect can be obtained even in other cylindrical shapes such as a quadrilateral.

In addition, in FIG. 2, the two lead portions 6a of the voice coil 6 are located above the two cutout portions 1c, but only one lead portion 6a may be located on the upper portion of the cutout portion 1c, and the other lead portion 6a passes through the other The path is exported.

The speaker of the present invention can be made thinner by providing a notch at the position of the yoke relative to the position of the lead part of the coil end drawn from the voice coil.