Patent Translate Powered by EPO and Google Notice This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate, complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or financial decisions, should not be based on machine-translation output. DESCRIPTION JPS61219296 [0001] FIELD OF THE INVENTION The present invention relates to an electromagnetic speaker with reduced leakage flux. 2. Related Art In recent years, the audio industry has been transitioning to the so-called M era by merging with visual devices, and a large number of magnetically shielded speakers that do not cause color shift on the screen even when installed next to a television are commercially available However, the provision of cheaper magnetic shielding speakers is awaited. Hereinafter, a conventional magnetic shielding speaker will be described with reference to the drawings. FIG. 2 is a cross-sectional view of a conventional magnetic shielding speaker. 1 is a yoke, 11L is a center pole portion of the yoke, 2 is a magnet bonded onto the yoke 1, 3 is a top plate bonded onto the magnet 2, 4 is a magnetic circuit composed of the above components, 6 Is a frame fixed to the top plate 3, 6 is a gasket, 7 is an edge with one end adhered to the frame 6, 8 is a diaphragm supported by the edge 7, 9 is a voice coil, and 1o is a damper for supporting the voice coil Reference numeral 11 denotes a dust cap adhered to the central portion of the diaphragm 8. Reference numeral 12 denotes a cancel magnet that is magnetized in the reverse polarity to the magnet 2 and is adhered to the bottom of the yoke, and 13 is a magnetic shielding cover that is adhered to the bottom of the cancel magnet 12. The operation of the magnetic shielding speaker configured as described above will be described below. Assuming that there is no temporary magnet 12 and there is no cancel magnet 12 and only the magnetic shielding cover 13 is coupled, the magnetic flux leaking from the top plate 3 to the outside is only the one directed to the center pole 1 turtle of the yoke 1. The magnetic flux leaking from the upper surface and the side surface of the top plate 3 to the bottom surface and the side surface of the yoke 1 passes through the air shielding cover 13 and hardly leaks to the outside of the magnetic shielding cover 13. However, in this state, since the magnetic resistance between the magnetic shielding cover 13 and the bottom surface of the yoke 1 is reduced, the magnetic flux density of the magnetic gap formed by the center pole portion 1 & and the inner 13-05-2019 1 peripheral surface of the top plate 3 is lowered to deteriorate the efficiency of the speaker. When the cancel magnet 12 magnetized in reverse polarity is inserted between the magnetic shielding cover 13 and the bottom of the yoke 1, the magnetic resistance between this and the magnetic flux apparently appears, and the magnetic flux leaking from the magnetic shielding cover 13 to the bottom of the yoke 1 almost disappears. Can reduce the efficiency of Problems to be solved by the invention However, in the configuration as described above, since the cancel magnet 12 and the magnetic shielding cover 13 are fixed to the joke 1 by adhesion, a drying time after adhesion is required. It had the problem of taking time. Also, the acrylic adhesive used as an adhesive for these parts is very expensive and has low thermal conductivity, so the heat dissipation from the heat generated by the voice coil 9 and transmitted to the yoke 1 is inhibited, and the input resistance of the speaker Also had the problem of dropping the SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an inexpensive magnetic shielding speaker without impairing the input resistance. Means for Solving the Problems In order to solve the above problems, the magnetic shielding speaker of the present invention is configured to screw and fix the cancel magnet and the magnetic shielding cover to the yoke. In the present invention, since the magnetic shielding cover and the cancel magnet are fixed to the joke by the screw according to the above-described configuration, the step of applying the adhesive and the drying time thereof are unnecessary, and the manufacturing man-hour can be significantly shortened. It is possible to reduce the cost because it does not use a common acrylic adhesive. Furthermore, since there is no adhesive that inhibits thermal conduction between the yoke and the cancel magnet, and between the cancel magnet and the magnetic shielding cover, the thermal conductivity is good and the input resistance is not reduced. EXAMPLES The following describes a magnetic shielding speaker according to an example of the present invention with reference to the drawings. FIG. 1 only shows a cross-sectional view of the magnetic shielding speaker in an embodiment of the present invention. In FIG. 1, the same parts as in FIG. 2, which is a conventional example, are assigned the same reference numerals and descriptions thereof will be omitted. The magnetic shielding cover 13 has a hole at its central portion for passing the screw 14, and the yoke 1 is provided with a screw hole for the screw 14 to be fitted. The operation of the magnetic shielding speaker configured as described above will be described with reference to FIG. The operation of the magnetic shield is completely the same as that of the conventional example, so the description will be omitted. Since no adhesive is used between the cancel magnet 12 and the magnetic shielding cover 13, and the space between the cancel magnet 12 and the yoke 1 is also fixed to the yoke 1 by the screw 14 without using an adhesive, The process is extremely simple and does not require drying time. Since no expensive adhesive is required, the cost can be reduced and the heat conductivity is not impeded. As a result, the heat transmitted from the voice coil 9 to the yoke 1 is efficiently transmitted to the cancel magnet 12 and the magnetic shield cover 13 As a result, the input resistance can be prevented from decreasing. In the case of fc using a material with high permeability such as iron for the screw 14, both electrodes of the 13-05-2019 2 cancel magnet 12 are shorted with the screw 14, and as a result, between the center pole portion 1 a and the top plate 3. Although the magnetic flux density will be lowered, if the screw 14 is made of a material with a low permeability such as brass, the above-mentioned decrease in magnetic flux density will not occur at all. Effect of the Invention As described above, according to the present invention, the step of applying the adhesive and the drying time thereof are unnecessary by fixing the cancel magnet and the magnetic shielding cover to the yoke with the screw without using the adhesive #) manufacture Since the number of man-hours can be significantly reduced and expensive adhesives are not used, the cost can be reduced. Furthermore, since there is no adhesive that inhibits thermal conduction between the yoke and cancel magnet, and between the cancel magnet and the magnetic shielding cover, the thermal conductivity is good, and the heat buildup of the voice coil is reduced, so the input resistance is not reduced. It has an excellent effect. Furthermore, the use of a low permeability material such as brass for the screw can also prevent the decrease in magnetic flux density. [0002] Brief description of the drawings [0003] FIG. 1 is a cross-sectional view of a magnetic shielding speaker in an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a conventional magnetic shielding speaker. 1 · · · · · · · · · · · · · · · · · · · · · · · Cancel magnet, 13 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Cancel magnet, 13 · · · · · · · · · · · · · magnetic shielding cover. Name of Agent Attorney Nakao Toshio One other person Ml Fig. 2, 7! ... yoke 2 ... Mak ° 'net 3 ... door-to Bua 1-door 4 ··· h story rice 1i Michino 2 - - CEN Yang tJl- Mak' s Component <ゝ 3? 13-05-2019 3
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