JP3973056B2 - Electromagnetic sound generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a small electromagnetic sounding body mainly used in portable electronic devices.
[0002]
[Prior art]
Various products such as electronic devices have been reduced in size and weight with the passage of time, and have been used in large quantities. Along with this, it has been required to supply a large amount of small electromagnetic sounding bodies at a low cost.
[0003]
However, a small electromagnetic sounding body is small and is handled in large quantities, and may be accidentally dropped in the assembly stage and the distribution stage. When falling on the hard floor from the work table, the diaphragm may be plastically deformed depending on the dropping posture. Conventionally, as a measure to prevent plastic deformation of the diaphragm due to such a drop, a part for limiting the amount of movement is provided so that the diaphragm does not move greatly, and the diaphragm limits the amount of movement. In order to buffer or eliminate the force that collides with the portion to be moved, the shape of the portion that limits the amount of movement of the diaphragm has been devised.
[0004]
Next, a conventional example will be described with reference to FIGS. FIG. 5 is a cross-sectional view of an electromagnetic sounding body in a conventional example. FIG. 6 is an E portion detail view showing the E portion of FIG. 5 in an enlarged manner.
[0005]
First, a conventional example will be described with reference to FIG. The case body 101 includes an upper case 102 made of plastic and a bottom plate 103 made of a magnetic material. The case body 101 has a cylindrical side surface 101a, a flat upper end surface 101b, and a flat lower end surface 101c. It has a shape. The cup-shaped upper case 102 is fitted over the outer periphery of the flat and circular bottom plate 103 from the top. A magnetic core 106 is planted in the center of the upper surface of the bottom plate 103, and a coil 107 is formed by winding a winding around the magnetic core 106. Also, an insulating plate 104 is attached to the lower surface of the bottom plate 103, and two terminals 105 are planted on the insulating plate 104. Both terminals of the coil 107 are not connected to the two terminals 105 (not shown). Are connected to each other. A diaphragm center restricting portion 102a is formed at the inner center of the upper case 102, and is opposed to a diaphragm 110 described later with a slight gap. The diaphragm 110 receives an external impact and moves upward. Jumping out is restricted, and the diaphragm 110 is prevented from colliding with other parts such as the inner wall of the permanent magnet 108 to be plastically deformed. In addition, a sound outlet 102b is formed in the center of the diaphragm center restricting portion 102a to communicate the air inside the case body 101 with the outside air. A cylindrical permanent magnet 108 is fixed to the upper surface of the bottom plate 103 and in close contact with the inner side of the upper case 102, and is magnetized in the axial direction, that is, the vertical direction. That is, the magnetic core 106, the coil 107, and the permanent magnet 108 constitute an actuator 109 that excites a diaphragm 110 described later. A flat and circular diaphragm 110 is attracted to the upper end surface of the permanent magnet 108 by the magnetic attraction force of the permanent magnet 108, and the central portion of the diaphragm 110 faces the upper end of the magnetic core 106 with a slight gap. ing.
[0006]
In FIG. 6, the upper end of the permanent magnet 108 is formed in a step shape, the upper case 102 is fitted on the outer periphery and the upper stage, and the diaphragm 110 is placed on the lower stage, and is attracted by the magnetic attractive force of the permanent magnet 108. . The upper case 102 on the upper stage of the permanent magnet 108 protrudes above the diaphragm 110 and restricts the diaphragm peripheral edge limiting portion 102c in order to restrict the diaphragm 110 from jumping upward in response to an external impact. Furthermore, in order to prevent the diaphragm 110 from colliding with the diaphragm peripheral edge restricting part 102c and plastically deforming, the tip of the diaphragm peripheral restricting part 102c is buffered so as to buffer this collision force. It is formed in a large arc.
[0007]
Next, the operation of the above-described conventional example will be described. When the electromagnetic type sounding body of the conventional example shown in FIGS. 5 and 6 falls onto the floor from the work table, for example, the upper case 102 is made of plastic, so it bounces several times, and the magnet of the permanent magnet 108 The diaphragm 110 that is attracted to the upper end surface of the permanent magnet 108 by an attractive force may come off the permanent magnet 108 due to dynamic inertia. Although it is restrained that the diaphragm center restricting portion 102a and the diaphragm peripheral edge restricting portion 102c jump out greatly, it may collide with the diaphragm peripheral restricting portion 102c and be plastically deformed. Although the frequency and the degree of plastic deformation of the diaphragm 110 were improved by making the tip of the diaphragm peripheral limit portion 102c a large arc, it was insufficient. Therefore, the yield in the assembly stage and the distribution stage is lowered, which is an obstacle such as cost reduction.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide an inexpensive electromagnetic sounding body that reduces the impact when dropped and prevents plastic deformation of the diaphragm without changing the structure of the main body.
[0009]
[Means for Solving the Problems]
To achieve the above object, the electromagnetic sound of the present invention, a case body, possess a diaphragm held in the interior of the case body, and an actuator for vibrating the vibrating plate, of the casing body The side surface is covered with a cushion sheet, the cushion sheet is made of urethane foam, and the cushion sheet protrudes from the end surface of the case body by a certain amount .
[0011]
The cushion sheet has a flat plate shape and is wound around a side surface of the case body.
[0012]
Further, the cushion sheet is bonded to at least one end face of the case body.
[0013]
Further, the cushion sheet is characterized in that projecting from the side to cover the end faces of the case body.
[0014]
Further, the cushion sheet is bonded by a bonding material.
[0015]
Further, the bonding material is a double-sided adhesive tape.
[0016]
Further, the bonding material is an adhesive.
[0017]
Further, the cushion sheet is in a tube shape having elasticity, and the cushion sheet is attached to the case body by elasticity.
[0018]
In addition, the cushion sheet has a heat-shrinkable tube shape that shrinks when heated, and the cushion sheet is attached to the case body by heat-shrinkability.
[0019]
Further, the cushion sheet attached to the side surface of the case body protrudes from at least one end surface of the case body.
[0020]
Further, the cushion sheet is formed by a molding die and then attached to the case body.
[0021]
Furthermore, the cushion sheet covers from the side surface of the case body to at least one end surface.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below based on examples with reference to the drawings.
FIG. 1 shows an electromagnetic type sounding body according to a first embodiment of the present invention, wherein (a) shows a cross-sectional view and (b) is a top view of (a). 2A and 2B show an electromagnetic type sounding body according to a second embodiment of the present invention, in which FIG. 2A is a cross-sectional view and FIG. 2B is a top view of FIG. FIG. 3 shows an electromagnetic type sounding body according to a third embodiment of the present invention, in which (a) shows a cross-sectional view and (b) is a top view of (a). 4A and 4B show an electromagnetic type sounding body according to a fourth embodiment of the present invention. FIG. 4A is a sectional view and FIG. 4B is a top view of FIG.
[0023]
First, the structure of the first embodiment will be described with reference to FIG. Similar to the above-described conventional example, the case body 1 includes an upper case 2 made of plastic and a bottom plate 3 made of a magnetic material, and has a cylindrical side surface 1a and a flat upper end surface 1b. And a flat lower end surface 1c form a cylindrical shape. The cup-shaped upper case 2 is fitted over the outer periphery of the flat and circular bottom plate 3. A magnetic core 6 is planted in the center of the upper surface of the bottom plate 3, and a coil 7 is formed on the magnetic core 6 by winding a winding. An insulating plate 4 is attached to the lower surface of the bottom plate 3, two terminals 5 are planted on the insulating plate 4, and both terminal wires (not shown) of the coil 7 are wound on the two terminals 5. ) Are connected to each other. Further, a diaphragm center restricting portion 2a is formed at the inner center of the upper case 2, and a diaphragm peripheral restricting portion 2c is formed at the inner periphery, and is opposed to the diaphragm 10 described later with a slight gap. The plate 10 is restricted from jumping upward in response to an external impact, and the diaphragm 10 is prevented from being plastically deformed. A cylindrical permanent magnet 8 is fixed to the upper surface of the bottom plate 3 and in close contact with the inside of the upper case 2, and is magnetized in the axial direction, that is, in the vertical direction. That is, the magnetic core 6, the coil 7, and the permanent magnet 8 constitute an actuator 9 that excites a diaphragm 10 described later. A flat circular diaphragm 10 is adsorbed to the upper end surface of the permanent magnet 8 by the magnetic attractive force of the permanent magnet 8, and the central portion of the diaphragm 10 faces the upper end of the magnetic core 6 with a slight gap. ing.
[0024]
On the side surface 1a of the case body 1 similar to the conventional example described above, a flat cushion sheet 12a having a width larger than the height of the side surface 1a of the case body 1 by the protruding amount S extends from the upper end surface 1b of the case body 1. It is wound so as to protrude by the protruding amount S and is joined by the joining material 11. As a material of the cushion sheet 12a, flexible natural rubber (NR), isoprene rubber (IR), urethane foam and the like are suitable. As the bonding material 11, a double-sided adhesive tape or an adhesive can be used. Thus, even if the electromagnetic sounding body in which the cushion sheet 12a is wound around the side surface 1a of the case body 1 falls on the floor from the work table, for example, the cushion sheet 12a is deformed, so that the impact force is increased. Since it absorbs, the diaphragm 10 does not plastically deform. In particular, since the cushion sheet 12a protrudes from the upper end surface 1b of the case body 1 by the protrusion amount S, the corners of the side surface 1a and the upper end surface 1b of the upper case 2 where the vibration plate 10 is easily plastically deformed collide with the floor surface. It is effective when falling in a posture to do. In this embodiment, the cushion sheet 12a is configured to protrude only from the upper end surface 1b of the case body 1. However, the cushion sheet 12a may be configured to protrude from the lower end surface 1c of the case body 1. Needless to say, it may be configured to protrude from the surface.
[0025]
Next, the structure of the second embodiment will be described with reference to FIG. The case body 1 and the internal structure of the case body 1 are the same as those in the first embodiment described above. A circular flat cushion sheet 12b having a diameter larger than the side surface 1a of the case body 1 by a protruding amount S is joined to the upper end surface 1b and the lower end surface 1c of the case body 1 similar to the first embodiment described above. Joined by the material 11. As the bonding material 11, a double-sided adhesive tape or an adhesive can be used. The material of the cushion sheet 12b is the same as that of the cushion sheet 12a of the first embodiment described above. Thus, even if the electromagnetic sounding body in which the cushion sheet 12b is joined to the upper end surface 1b and the lower end surface 1c of the case body 1 falls on the floor from the work table, for example, the cushion sheet 12b is deformed. Since the impact force is absorbed by this, the diaphragm 10 is not plastically deformed. In particular, since the cushion sheet 12b protrudes from the side surface 1a of the case body 1 by the protrusion amount S, the corner portion between the side surface 1a of the upper case 2 and the upper end surface 1b or the lower end surface 1c where the diaphragm 10 is easily plastically deformed. It is effective when it collides with a surface. In the present embodiment, the cushion sheet 12b is bonded to the upper end surface 1b and the lower end surface 1c of the case body 1, respectively, but it goes without saying that the cushion sheet 12b may be bonded only to one end surface. .
[0026]
Next, the structure of the third embodiment will be described with reference to FIG. The case body 1 and the internal configuration of the case body 1 are the same as in the second embodiment described above. The outer periphery of the side surface of the case body 1 similar to the second embodiment described above has a length that is larger than the height of the side surface 1 a of the case body 1 by the protruding amount S, and the elasticity and the outer peripheral length of the case body 1 A tube-shaped cushion sheet 12c having a slightly shorter inner peripheral length is placed so as to protrude from the upper end surface of the case body 1 by a protrusion amount S, and is attached to the case body 1 by elasticity. The material of the cushion sheet 12c is the same as that of the cushion sheet 12a of the first embodiment described above. Further, it may be a heat-shrinkable tube that shrinks by heating, and a tubular cushion sheet 12c having an inner peripheral length slightly longer than the outer peripheral length of the case body 1 is covered with the case body 1, and the cushion sheet 12c is attached. It may be contracted by heating and attached to the case body 1. In this way, even if the electromagnetic sounding body with the cushion sheet 12c placed on the side surface 1a of the case body 1 falls on the floor from the work table, for example, the cushion sheet 12c is deformed, so that the impact force is increased. Since it absorbs, the diaphragm 10 does not plastically deform. In addition, it cannot be overemphasized that the cushion sheet 12c may be comprised so that it may protrude from the lower end surface 1c of the case body 1, and it may be comprised so that it may protrude from both end surfaces.
[0027]
Next, the structure of the fourth embodiment will be described with reference to FIG. The case body 1 and the internal structure of the case body 1 are the same as in the third embodiment described above. It attaches to the case body 1 similar to 3rd Example mentioned above by extending and covering the cushion sheet 12d which has the elasticity shape | molded with the shaping | molding die. As a molding method using a molding die, there are a method of molding a flat cushion sheet by brazing or a method of molding by injection molding. Further, the cushion sheet 12d may be attached to the case body 1 by elasticity, and a tube having elasticity and an inner circumference length slightly shorter than the outer circumference length of the case body 1 may be attached as in the third embodiment. As another method, the length of the side surface of the case body 1 is a length obtained by adding an upper end surface cover amount S1 and a lower end surface cover amount S2, and further adding a contraction amount. Alternatively, it may be attached to the case body 1 by being covered with a cushion sheet 12d of a heat-shrinkable tube that has a long inner peripheral length and contracts by heating, and the cushion sheet 12d is contracted by heating. Thus, in the present embodiment, the cushion sheet 12d covers the side surface 1a, the upper end surface 1b, the lower end surface 1c, and all the corners of the case body 1, and the surface of the case body 1 is exposed. Since the area is small, for example, even if it falls from the work table and falls on the hard projection, the probability that the exposed portion of the case body 1 will collide with the hard projection is very small, and the diaphragm 10 is plastic. There is almost no shock that deforms. In addition, you may comprise so that it may cover with the cushion sheet 12d from the side surface 1a to one end surface.
[0028]
【The invention's effect】
As described above, according to the present invention, an electromagnetic sounding body that prevents plastic deformation of the diaphragm can be obtained by covering at least a part of the case body with the cushion sheet.
[0029]
Further, by covering at least a part of the case body with the cushion sheet, the impact at the time of dropping can be reduced at a low cost without changing the structure of the main body portion.
[0030]
In addition, since the cushion sheet protrudes from the side surface or end surface of the case body, when the corner part falls in such a posture as to collide with the floor surface, the impact force is buffered by the deformation of the protrusion part of the cushion sheet. Therefore, the buffering effect is great.
[0031]
Moreover, since the cushion sheet is joined by the joining material, it is easy to automate the joining process.
[0032]
Moreover, since the cushion sheet is in the form of a tube having elasticity and the cushion sheet is attached to the case body by elasticity, the attachment process is easy and can be manufactured at low cost.
[0033]
In addition, the cushion sheet is in the form of a heat-shrinkable tube that shrinks when heated, and since the cushion sheet is attached to the case body by heat-shrinkability, the attachment process is easy and can be manufactured inexpensively. it can.
[0034]
In addition, since the cushion sheet is molded by the molding die and then mounted on the case body, the mounting process is easy and can be manufactured at low cost.
[0035]
Furthermore, since the cushion sheet covers from the side surface to the end surface of the case body, the area where the surface of the case body is exposed is small, and the probability that the exposed portion of the case body collides with a hard protrusion is very small. The plate is hardly subjected to an impact that causes plastic deformation.
[Brief description of the drawings]
FIG. 1 shows an electromagnetic type sounding body according to a first embodiment of the present invention, in which (a) shows a cross-sectional view and (b) is a top view of (a).
2A and 2B are electromagnetic sounding bodies according to a second embodiment of the present invention, in which FIG. 2A is a cross-sectional view and FIG. 2B is a top view of FIG.
FIG. 3 shows an electromagnetic type sounding body according to a third embodiment of the present invention, in which (a) is a cross-sectional view and (b) is a top view of (a).
4A and 4B are electromagnetic sounding bodies according to a fourth embodiment of the present invention, in which FIG. 4A is a sectional view and FIG. 4B is a top view of FIG.
FIG. 5 is a cross-sectional view of an electromagnetic sounding body in a conventional example.
6 is an enlarged view of a portion E showing the portion E of FIG. 5 in an enlarged manner. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,101 Case body 1a, 101a Side surface 1b, 101b Upper end surface 1c, 101c Lower end surface 2, 102 Upper case 2a, 102a Diaphragm center restriction | limiting part 102b Sound emission port 2c, 102c Diaphragm periphery restriction | limiting part 3, 103 Bottom plate 4, 104 Insulating plate 5, 105 Terminal 6, 106 Magnetic core 7, 107 Coil 8, 108 Permanent magnet 9, 109 Actuator 10, 110 Diaphragm 11 Bonding material 12a, 12b, 12c, 12d Cushion sheet

Claims (1)

Possess a case body, a vibration plate which is held inside of the case body, and an actuator for vibrating the vibrating plate, covers the side surface of the case body in the seat cushion, the material of the cushioning sheet is formed of urethane foam The electromagnetic sounding body is characterized in that a cushion sheet projects from the end surface of the case body by a certain amount as it is.

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