JPH02275994A - Electromagnetic type sounding body - Google Patents

Abstract

PURPOSE:To prevent a plastic magnet from chipping and a cracking and a coil from disconnection by providing a cut part where the lead wire of the coil is led out in the reverse surface of the plastic magnet arranged on a plate together with the coil, and performing insert molding in a mold integrated with a frame. CONSTITUTION:The plastic magnet is used as the magnet 22 of a field part, the cut part 37 where the lead wire 36 of the coil 21 is run is formed in the reverse surface of the magnet 22, and the insert molding is performed in the mold part 28 united with the frame 27. Thus, the plastic magnet is used. Consequently, the magnet neither chips nor cracks when a component is transported or supplied to the metallic mold, so no powder of the magnet is reduced and such a complicate shape that an escape groove for the lead wire is provided can easily worked.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electromagnetic sounding body used as a sounding body in various industrial fields such as home appliances, office automation equipment, and automobiles.

BACKGROUND OF THE INVENTION In recent years, small and thin electromagnetic sounding bodies that generate sound through acoustic vibrations have been attracting attention, and their structures are becoming more complex as they become more multifunctional.

Therefore, an example of a wash-resistant electromagnetic sounding body mounted on a circuit board, which we proposed earlier, will be explained with reference to the drawings.

Fig. 5 is a plan view of a conventional electromagnetic sounding body, and Fig. 6 is a plan view of a conventional electromagnetic sounding body.
It is a front sectional view taken along the line A-0-B in the figure.

A coil 3 is fixed to a magnetic circuit consisting of a plate 1 having a magnet 4 and a center ball 2, and a frame 9 that fixes the plate 1 to form a field section, and a diaphragm with high magnetic permeability is connected through a narrow gap 8. A metal diaphragm consisting of a suspension 11 and a suspension 12 is provided so as to be held at the upper end of the frame 9. The metal diaphragm is previously absorbed and supported by the plate 1 due to the DC magnetic field generated by the magnet 4, but when an AC signal is applied to the coil 3 through the terminal 5, AC magnetic flux is superimposed thereby, and an attractive force is generated. changes depending on the frequency of the AC signal, causing the metal diaphragm to vibrate and generate sound. The generated sound is amplified by the cavity 15 between the resonance cases 14 and is emitted to the outside through the sound emitting hole 16.

Since this is a wash-resistant type, a waterproof membrane 13 is provided on the upper surface of the frame 9 to which the metal diaphragm is attached, and two sound emitting holes 16 are provided at the lower side of the resonance case 14. Further, in order to directly mount the coil 3 on the board, the electrical coupling portion 6 between the wire 7 of the coil 3 and the terminal 5 is provided inside the resonant case 14 rather than outside. Further, the magnet 4 is wrapped in a resin molded part 10 so as not to be easily broken.

Further, in order to prevent the magnet 4 from slipping, even if it moves in the direction of the magnet stopper or in the circumferential direction of the molding die of the magnet mold part 10, it will not be exposed from the mold part 10.

Problems to be Solved by the Invention However, in such a structure, as shown in FIG. 7, the sintered magnet 4 is insert-molded in the mold part 10, but there are problems when transporting the parts or supplying the parts to the mold. Sometimes the magnet 4 will chip or break. As a result, fragments of the magnet 4 may enter the porcelain gap 18,
The magnet 4 may crack, resulting in poor performance, and if the lead wire 7 of the coil 3 comes out from the side of the coil 3, for example, it may catch on the corner of the magnet 4 and break.

The present invention aims to provide an electromagnetic sounding body that can solve these problems.

Means for Solving the Problem In order to solve this problem, the present invention uses a plastic magnet as the magnet of the field part, and provides a notch on the lower surface of a part of the magnet through which the lead wire of the coil is inserted. It is insert molded into a molded part that is integrated with the frame.

action The effect of this technical means is as follows.

In other words, by using Plus Deck magnets, the magnets do not chip or break when transporting the parts or feeding the parts into the mold, so no magnet powder is generated.

Furthermore, since it is a plastic magnet, complex shapes such as rounded corners and escape grooves for lead wires can be easily created.

EXAMPLE Hereinafter, an example of the present invention will be explained using FIGS. 1 to 4.

19 is a plate having a center pole 20, a coil 21 wound in a ring shape around the center pole 20 one above the plate, and a ring-shaped magnet 22 arranged around the outer periphery of this coil 21 to create a field. It makes up the department. Further, a connection 24 is arranged on the plate 19 to be electrically connected to the end of the coil 21 and led to a terminal 23.

These field parts include a cylindrical part 26 formed to cover the outer peripheral edge of the plate 19 and having a stepped part 25 at the upper end.
A frame 27 is formed, and when this frame 27 is formed, a mold part 28 is formed in which the magnet 22 and one coil of the plate 19 are molded at the same time, and only the center pole 20 is exposed on the upper surface of this mold part 28. It's out.

The stepped portion 25 of the cylindrical portion 26 of the frame 27 holds a peripheral portion of a metal diaphragm comprising a suspension 30 having a diaphragm 29 made of a high magnetic permeability material coupled to the center.

Furthermore, a waterproof membrane 31 is coupled to the upper surface of the metal diaphragm of the cylindrical portion 26 of the frame 27.

Further, a resonance case 32 is placed over the frame 27, and a cavity 33 is formed by this resonance case 32, and sound emission holes 34 are provided at two locations at the bottom of this resonance case 32.

When an AC signal is applied to the coil 21 through the terminal 23 in such a configuration, the resulting AC magnetic flux is superimposed, and the attractive force changes according to the frequency of the AC signal, causing the metal diaphragm to vibrate and generate sound. do. This generated sound is amplified by the cavity 33 of the resonance case 32, and the sound is amplified by the sound emission hole 34.
released to the outside through.

Further, numeral 35 is a part of a stopper formed from a molding die to prevent the magnet 22 from slipping.

Furthermore, a plastic magnet is used as the magnet 22 of the field section, and the glue-1 wire 36 of the coil 21 is drawn out from the lower surface of a part of the magnet 22 as shown in FIGS. 3 and 4. A notch 37 is provided, and the magnet 22 is insert-molded in a molded part 28 that is integrated with the frame 27, so that the magnet 22 is inserted into the molded part 28 as shown in FIG.
Even if the wire 36 comes out from the side of the coil 21 instead of the bottom,
Since the notch 37 of the magnet 22 can be avoided, the lead wire 36 will not be caught on the magnet 22 and disconnected.

Effects of the Invention The present invention uses a plastic magnet in which magnetic powder is mixed in resin as the magnet in the field part.
It is insert molded into a molded part that is integrated with the frame, and by using a plus deck magnet,
Performance variations due to chipped or cracked magnets, and gap defects due to magnet powder will no longer occur.

Furthermore, since magnets with complex shapes can be easily created,
By creating a shape that can avoid changes in the position of the coil lead wire, it is possible to eliminate wire breaks.

[Brief explanation of drawings]

Fig. 1 is a plan view of an electromagnetic sounding body according to an embodiment of the present invention, Fig. 2 is a sectional view taken along C-0-D of Fig. 1, Fig. 3 is a sectional view of the same essential parts, and Fig. 4 is a sectional view of the same main part. An enlarged view of the main parts, FIG. 5 is a plan view of a conventional electromagnetic sounding body, and FIG. 6 is a sectional view taken along A-0-B in FIG. 5.
FIG. 7 is a sectional view of the main part. 19...Plate, 20...Center pole, 21...Coil, 22...Magnet, 23...Terminal, 24... ...Connection part, 25...Step part, 26...Cylindrical part, 27...Frame, 28...Mold part, 29... ...Diaphragm, 30...
・Suspension, 31... Waterproof membrane, 32...
... Resonance case, 33 ... Cavity, 3
4...Sound emission hole, 35...Part of stopper. Name of agent Patent attorney Shigetaka Awano 1 person Irukunet 5' Line part Iku-shaped part 30-inch suspension 31- Rib water eel 32- Resonance case O- Cahety S-11-hole hole 35- Stopper Part 'Aan'-\-11 et al. 11/ \ l \ 1X ) 1, △, 7 \ / ノ/ l-

Claims (1)

[Claims] It is equipped with a field part consisting of a magnet and a coil placed on a plate, a frame surrounding the field part, and a resonance case having a metal diaphragm and a sound emitting hole arranged in the cylindrical part of the frame. A plastic magnet in which magnetic powder is mixed in resin is used as the magnet, a cutout is provided on the lower surface of a part of the magnet to draw out the lead wire of the coil, and the magnet is placed in a molded part that is integrated with the frame. Electromagnetic sounding body made by insert molding.