WO2008143466A1

WO2008143466A1 - Plate combining structure for audio appliance having closed flux and combining method thereof

Info

Publication number: WO2008143466A1
Application number: PCT/KR2008/002848
Authority: WO
Inventors: Joon-Bum An
Original assignee: Dae Han Special Metal Ind Co., Ltd
Priority date: 2007-05-22
Filing date: 2008-05-22
Publication date: 2008-11-27
Also published as: KR100812327B1; WO2008143466A4

Abstract

Disclosed are a plate connecting structure for an audio appliance having a closed magnetic flux path and a connecting method thereof. In the plate connecting structure, in which a voice coil is excited by an audio signal, the magnetic flux of the voice coil and the magnetic flux of a permanent magnet leaked between a yoke plate and a top plate cross each other such that the voice coil is vibrated according to the size and frequency of the audio signal, and a vibration plate attached to the voice coil is vibrated by the vibration of the voice coil to generate a sound wave, a pin insertion hole is formed through the permanent magnet, an insert pin is inserted into the pin insertion hole, and the yoke plate and the top plate are connected to both ends of the insert pin by welding.

Description

PLATE COMBINING STRUCTURE FOR AUDIO APPLIANCE HAVING CLOSED FLUX AND COMBINING METHOD

THEREOF

Technical Field

[1] The present invention relates to a plate connecting structure for an audio appliance having a closed magnetic flux path, in which components are firmly connected and a yoke plate and a top plate are connected to both ends of a permanent magnet to maximize the saturation of a magnetic field, and more particularly to a plate connecting structure for an audio appliance having a closed magnetic flux path and a connecting method thereof, in which an insert pin passes through a permanent magnet and a yoke plate and a top plate are welded to both ends of the insert pin to prevent the damage to the yoke plate, the top plate, and the permanent magnet and the increase of the total thickness. Moreover, the present invention relates to a plate connecting structure for an audio appliance having a closed magnetic flux path and a connecting method thereof, in which unnecessary layers, such as adhesive layers between plates and a permanent magnet, are omitted to maximize the saturation of a magnetic field, and the plates are connected to the permanent magnet by an electric welding method to automate a process for connecting the plates to the permanent magnet.

Background Art

[2] In general, each of audio appliances having a closed magnetic flux path, such as a micro speaker or an earphone (hereinafter, is commonly called "audio appliances having a closed magnetic flux path"), is one of speakers connected to audio appliances, such as a portable terminal, a cassette, or a CD player.

[3] FIGs. 9 and 10 respectively illustrate examples of these audio appliances having a closed magnetic flux path.

[4] As shown in FIGs. 9 and 10, in an audio appliance having a closed magnetic flux path, a voice coil 100 is excited by an audio signal, the magnetic flux of the voice coil 100 and the magnetic flux of a permanent magnet 400 leaked between a yoke plate 200 and a top plate 300 cross each other and thus the voice coil 100 is vibrated according to the size and frequency of the audio signal, and a vibration plate 500, to which the voice coil 100 is attached, is vibrated to generate a sound wave.

[5] In the above audio appliance having a closed magnetic flux path, the top plate 300 and the yoke plate 200 are respectively fixed to both ends of the permanent magnet 400. Here, the top plate 300 and the yoke plate 200 are respectively fixed to both ends of the permanent magnet 400 using a rivet 900, as shown in FIG. 9, or using adhesive layers 900' as shown in FIG. 10.

[6] In case that the top plate 300 and the yoke plate 200 are fixed to the permanent magnet 400 using the rivet 900, the top plate 300, the yoke plate 200, and the permanent magnet 400 may be deformed or broken due to an impact applied thereto in a process of applying pressure to both ends of the rivet 900. Further, a riveting process is required, and thus the total number of processes is increased.

[7] Further, in case that the top plate 300 and the yoke plate 200 are fixed to the permanent magnet 400 using the adhesive layers 900' as shown in FIG. 10, the adhesive layers 900' which are unstable, may be separated from the top plate 300, the yoke plate 200, and the permanent magnet 400, or the total thickness of the connecting structure may be increased.

[8] Moreover, the magnetic field of the permanent magnet 400 is not sufficiently saturated in a space, in which the closed magnetic flux path is formed, due to the adhesive layers 900'. Disclosure of Invention Technical Problem

[9] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a plate connecting structure for an audio appliance having a closed magnetic flux path, in which an insert pin is installed in a permanent magnet and a top plate and a yoke plate are respectively fixed to both ends of the permanent magnet by welding the top plate and the yoke plate to both ends of the insert pin to prevent damage to parts and prevent the increase in the total thickness, and any adhesive layer is omitted to maximize the saturation of a magnetic field.

[10] It is another object of the present invention to provide a plate connecting structure for an audio appliance having a closed magnetic flux path, in which the welding between plates and an insert pin is automated with a welding device and thus the total assembly process of the audio appliance is automated. Technical Solution

[11] In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a plate connecting structure for an audio appliance having a closed magnetic flux path, in which a voice coil is excited by an audio signal, the magnetic flux of the voice coil and the magnetic flux of a permanent magnet leaked between a yoke plate and a top plate cross each other such that the voice coil is vibrated according to the size and frequency of the audio signal, and a vibration plate attached to the voice coil is vibrated by the vibration of the voice coil to generate a sound wave, wherein a pin insertion hole is formed through the permanent magnet, an insert pin is inserted into the pin insertion hole, and the yoke plate and the top plate are connected to both ends of the insert pin by arc welding or resistance welding.

[12] In accordance with another aspect of the present invention, there is provided a method for connecting a yoke plate and a top plate to both ends of a permanent magnet of an audio appliance having a closed magnetic flux path, in which a voice coil is excited by an audio signal, the magnetic flux of the voice coil and the magnetic flux of the permanent magnet leaked between the yoke plate and the top plate cross each other such that the voice coil is vibrated according to the size and frequency of the audio signal, and a vibration plate attached to the voice coil is vibrated by the vibration of the voice coil to generate a sound wave, comprising inserting an insert pin into a pin insertion hole formed through the permanent magnet, and welding the yoke plate and the top plate to both ends of the insert pin, wherein the permanent magnet has a long cylindrical shape provided with the pin insertion hole, and the permanent magnet provided with the insert pin inserted into the pin insertion hole is produced by cutting the permanent magnet on condition that the insert pin is inserted into the pin insertion hole, or inserting the insert pin, which was cut, into the pin insertion hole of the permanent magnet, which was cut. Brief Description of the Drawings

[13] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[14] FIG. 1 is a cross-sectional view illustrating different embodiments of an audio appliance having a closed magnetic flux path with a plate connecting structure in accordance with the present invention;

[15] FIG. 2 is an exploded perspective view illustrating one embodiment of the plate connecting structure for the audio appliance in accordance with the present invention;

[16] FIG. 3 is an exploded perspective view illustrating another embodiment of the plate connecting structure for the audio appliance in accordance with the present invention;

[17] FIG. 4 is a perspective view illustrating the plate connecting structure of FIG. 3;

[18] FIG. 5 is a perspective view illustrating different embodiments of an insert pin provided on the plate connecting structure for the audio appliance in accordance with the present invention;

[19] FIG. 6 is a cross-sectional view illustrating another embodiment of the insert pin in a used state provided on the plate connecting structure for the audio appliance in accordance with the present invention;

[20] FIGs. 7 and 8 are enlarged cross-sectional views respectively illustrating different embodiments of plate connection parts of the audio appliance in accordance with the present invention; and [21] FIG. 9 is a cross-sectional view illustrating a conventional audio appliance having a closed magnetic flux path with a plate connecting structure; and

[22] FIG. 10 is a cross-sectional view illustrating another conventional audio appliance having a closed magnetic flux path with a plate connecting structure. Best Mode for Carrying Out the Invention

[23] Now, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings.

[24] FIG. 1 is a cross-sectional view illustrating different embodiments of an audio appliance having a closed magnetic flux path with a plate connecting structure in accordance with the present invention, FIG. 2 is an exploded perspective view illustrating one embodiment of the plate connecting structure for the audio appliance in accordance with the present invention, FIG. 3 is an exploded perspective view illustrating another embodiment of the plate connecting structure for the audio appliance in accordance with the present invention, FIG. 4 is a perspective view illustrating the plate connecting structure of FIG. 3, FIG. 5 is a perspective view illustrating different embodiments of an insert pin provided on the plate connecting structure for the audio appliance in accordance with the present invention, FIG. 6 is a cross-sectional view illustrating another embodiment of the insert pin in a used state provided on the plate connecting structure for the audio appliance in accordance with the present invention, and FIGs. 7 and 8 are enlarged cross-sectional views respectively illustrating different embodiments of plate connection parts of the audio appliance in accordance with the present invention.

[25] As shown in FIGs. 1 to 8, a plate connecting structure for an audio appliance having a closed magnetic flux path in accordance with the present invention is formed by welding a yoke plate 2 and a top plate 3 to both ends of an insert pin 10.

[26] The audio appliance of the present invention includes, as described above, a voice coil 1 excited by an audio signal, a permanent magnet 4 generating a magnetic flux, which crosses the magnetic flux of the voice coil 1, and the yoke plate 2 and the top plate 3 respectively installed at both ends of the permanent magnet 4.

[27] Further, the voice coil 1 is installed at the outer or inner part of the permanent magnet

4, and a vibration plate 5 is connected to one end of the voice coil 1. That is, the voice coil 1 is wounded in a ring shape on the outer part of the permanent magnet 4, and the vibration plate 5 is installed at cylindrical end of the voice coil 1, as shown in FIG. 1, such that the vibration plate 5 is vibrated by the vibration of the voice coil 1 and thus generates a sound wave.

[28] Hereinbefore, the schematic constitution of the audio appliance in accordance with the present invention was described in brief. Here, only some components of the audio appliance were described, and thus a description of other components of the audio appliance, which are equal or similar to those of a general audio appliance having a closed magnetic flux path, will be omitted. Now, only a structure of connecting the yoke plate 2 and the top plate 3 to both ends of the permanent magnet 4, which is the subject matter of the present invention, will be described in detail.

[29] A unit for fixing the yoke plate 2 and the top plate 3 to both ends of the permanent magnet 4 is the insert pin 10, as described above, and the fixation of the yoke plate 2 and the top plate 3 to both ends of the permanent magnet 4 is achieved by welding.

[30] That is, the insert pin 10 is fixed to a pin insertion hole 41, which is formed through the permanent magnet 4, and then the yoke plate 2 and the top plate 3 are welded to both ends of the insert pin 10.

[31] During the welding, any welding method, such as arc welding or resistance welding, may be used.

[32] The insert pin 10 has a simple cylindrical shape, as shown in FIGs. 2 and 3.

[33] Here, the insert pin 10 has an outer diameter, which is larger than the inner diameter of the pin insertion hole 41 formed through the permanent magnet 4, and is inserted into the pin insertion hole 41 by interference fit, thus preventing the insert pin 10 from being shaken in the pin insertion hole 41 or being separated from the pin insertion hole 41.

[34] An interference fit part 11 is formed on the insert pin 10 by thickening the middle portion of the insert pin 10, as shown in FIG. 5. That is, the interference fit part 11 having an outer diameter, which is larger than the inner diameter of the pin insertion hole 41 formed through the permanent magnet 4, is formed on the middle portion of the insert pin 10, such that only the interference fit part 11 can be inserted into the pin insertion hole 41 of the permanent magnet 4 by interference fit.

[35] Further, as shown in FIG. 5C, the interference fit part 11 formed on the insert pin 10 is provided with uneven regions 1 Ia so that the uneven regions 11a can be distorted when the insert pin 10 is inserted into the pin insertion hole 41 by interference fit in case that the outer diameter of the interference fit part 11 is excessively increased, thus preventing the permanent magnet 4 from being broken.

[36] Further, as shown in FIG. 6, a bending part 12 is formed on the insert pin 10 so that the bending part 12 carries out a spring action on condition that the bending part 12 is inserted into the pin insertion hole 41 formed through the permanent magnet 4 and thus is not separated from the pin insertion hole 41.

[37] Although the insert pins 10 having various structures were described above, the scope of the present invention is not limited thereby.

[38] The insert pin 10 may have the same length as the thickness of the permanent magnet

4 such that both ends of the insert pins 10 can coincide with both ends of the permanent magnet 4, as shown in FIG. 7, or have a longer length than the thickness of the permanent magnet 4 such that both ends of the insert pins 10 can protrude from both ends of the permanent magnet 4, as shown in FIG. 8.

[39] In case that the length of the insert pin 10 is longer than the thickness of the permanent magnet 4, as shown in FIG. 8, through holes 21 and 31 are respectively formed through the centers of the yoke plate 2 and the top plate 3, and thus both ends of the insert pin 10 are extended to middle portions of the through holes 21 and 31 of the yoke plate 2 and the top plate 3. By extending both ends of the insert pin 10 to the middle portions of the through holes 21 and 31 of the yoke plate 2 and the top plate 3, when both ends of the insert pin 10 are melted in welding, the molten ends of the insert pin 10 are located at the middle portions of the through holes 21 and 31 of the yoke plate 2 and the top plate 3, and thus the yoke plate 2 and the top plate 3 are easily welded to both ends of the insert pin 10.

[40] Hereinafter, a process of connecting the yoke plate 2 and the top plate 3 to both ends of the permanent magnet 4 of the audio appliance in accordance with the present invention will be described.

[41] As described above, a unit for connecting the yoke plate 2 and the top plate 3 to both ends of the permanent magnet 4 is the insert pin 10, and the yoke plate 2 and the top plate 3 are connected to the insert pin 10 by welding.

[42] In order to weld the yoke plate 2 and the top plate 3 to both ends of the insert pin 10, the insert pin 10 is first fixed to the pin insertion hole 41 formed through the permanent magnet 4. Here, the insert pin 10 is fixed to the pin insertion hole 41 by inserting the insertion pin 10, which was cut into a desired length in advance, into the pin insertion hole 41 formed through the permanent magnet 4, which was produced in advance, i.e., cut into a desired thickness in advance, by interference fit. However, in case that the permanent magnet 4 and the insert pin 10 are connected on condition that they were cut in advance, it is not easy to insert the short insert pin 10 into the pin insertion hole 41 of the thin permanent magnet 4. Thus, it is preferable that the insert pin 10 is first inserted into the pin insertion hole 41 before the permanent magnet 4 is cut, and then the permanent magnet 4 provided with the insert pin 10 is cut into a desired thickness.

[43] However, the present invention is not limited by the above embodiment.

[44] That is, the insert pin 10 having a long length is inserted into the pin insertion hole 41 of the permanent magnet 4 having a long cylindrical shape by interference fit, and then the permanent magnet 4 and the insert pin 10 are simultaneously cut on condition that the insert pin 10 is inserted into the pin insertion hole 41 of the permanent magnet 4. Thereby, it is possible to more easily fix the insert pin 10 to the pin insertion hole 41 formed through the permanent magnet 4. Industrial Applicability

[45] As apparent from the above description, the present invention provides a plate connecting structure for an audio appliance having a closed magnetic flux path and a connecting method thereof, in which an insert pin is installed in the center of a permanent magnet and a yoke plate and a top plate are respectively welded to both ends of the insert pin, thus easily connecting the yoke plate and the top plate to both ends of the permanent magnet.

[46] That is, the plates are welded to both ends of the insert pin, thus preventing the deformation or breakage of components generated by a conventional method for connecting plates using a rivet, and preventing the increase of the total thickness of the audio appliance due to adhesive layers.

[47] Further, the plate connecting structure of the present invention maximizes the saturation of a magnetic field in the closed magnetic flux path by the adhesive layers.

[48] Moreover, an automatic device for welding the insert pin and the plates is used, and thus the total assembly process of the audio appliance is automated and the productivity of the audio appliance is increased.

[49] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] A plate connecting structure for an audio appliance having a closed magnetic flux path, in which a voice coil is excited by an audio signal, the magnetic flux of the voice coil and the magnetic flux of a permanent magnet leaked between a yoke plate and a top plate cross each other such that the voice coil is vibrated according to the size and frequency of the audio signal, and a vibration plate attached to the voice coil is vibrated by the vibration of the voice coil to generate a sound wave, wherein a pin insertion hole is formed through the permanent magnet, an insert pin is inserted into the pin insertion hole, and the yoke plate and the top plate are connected to both ends of the insert pin by arc welding or resistance welding.

[2] The plate connecting structure according to claim 1, wherein the insert pin has a cylindrical shape, and an interference fit part having a larger diameter than the inner diameter of the pin insertion hole of the permanent magnet or a bending part pressing the inner wall of the pin insertion hole to carry out a spring action is formed at the middle portion of the insert pin.

[3] The plate connecting structure according to claim 2, wherein a plurality of uneven regions is formed on the interference fit part formed at the middle portion of the insert pin.

[4] The plate connecting structure accordingto claim 3, wherein both ends of the insert pins coincide with both ends of the permanent magnet.

[5] The plate connecting structure according to claim 3, wherein a through hole is formed through each of the yoke plate and the top plate, and both ends of the insert pin are extended to the middle portions of the through holes of the yoke plate and the top plate.

[6] A method for connecting a yoke plate and a top plate to both ends of a permanent magnet of an audio appliance having a closed magnetic flux path, in which a voice coil is excited by an audio signal, the magnetic flux of the voice coil and the magnetic flux of the permanent magnet leaked between the yoke plate and the top plate cross each other such that the voice coil is vibrated according to the size and frequency of the audio signal, and a vibration plate attached to the voice coil is vibrated by the vibration of the voice coil to generate a sound wave, comprising inserting an insert pin into a pin insertion hole formed through the permanent magnet, and welding the yoke plate and the top plate to both ends of the insert pin, wherein the permanent magnet has a long cylindrical shape provided with the pin insertion hole, and the permanent magnet provided with the insert pin inserted into the pin insertion hole is produced by cutting the permanent magnet on condition that the insert pin is inserted into the pin insertion hole, or inserting the insert pin, which was cut, into the pin insertion hole of the permanent magnet, which was cut.