JPH0434875B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of assembling a magnetic circuit for an external magnetic type speaker and an internal magnetic type speaker, which are composed of a top plate, a bottom plate, a magnet, and the like. Conventionally, when assembling the magnetic circuit of a speaker with such a configuration, it was necessary to firmly adhere these parts to each other, and adhesives were used for this purpose. As the adhesive, two-component epoxy adhesives and two-component acrylic adhesives are mainly used. In other words, when using a two-component epoxy adhesive, the main ingredient and curing agent must be mixed in advance, but the mixture will harden if it is not used within its pot life, so two-component mixtures are not recommended. The process required heating at a temperature of around 80°C for about 30 minutes using a coating machine. However, recently, the usage conditions for speakers have become stricter, such as repeated heating and cooling (-
40°←→100°C), but when subjected to such repeated heating and cooling, the epoxy adhesive cannot absorb the stress of expansion and contraction, and the magnet may crack. There were disadvantages such as causing On the other hand, two-component acrylic adhesives have a strong odor and can cause skin rash, and the surfaces of the top and bottom plates are usually made of chromate-plated steel plate to increase the rust prevention effect. Similar to epoxy adhesives, the adhesion of this plated surface varies widely depending on the processing conditions of the plating solution and changes over time of the plated steel plate, and this has the drawback of causing poor adhesion. Furthermore, similar to two-component epoxy adhesives, it has the disadvantage of causing cracks in the magnet during repeated heating and cooling (-40°C←→100°C). The present invention provides a novel speaker capable of overcoming the various drawbacks and difficulties encountered in conventional adhesive bonding and assembly of a speaker magnetic circuit consisting of a top plate, a bottom plate, a magnet, etc. The purpose is to obtain a method for assembling a magnetic circuit. In order to achieve this object, the present invention pre-coats the top plate, bottom plate, magnet, etc. that make up the magnetic circuit of the speaker with a heat-activated elastomer adhesive. The assembled parts are combined into the desired state, and then the combined parts are dielectrically or inductively heated with high frequency current under pressure, thereby bonding the parts to each other. It is characterized by instantaneous thermocompression bonding to each other. In addition, as a heat-activated elastomer adhesive, diene rubber 100 parts Metal oxide 3-20 parts Inorganic filler 0-30 parts Vulcanization accelerator 0-10 parts Phenol resin 30-150 parts Polymer-soluble organic solvent 100- It was confirmed that the one having a composition of 1200 parts was the best one. Hereinafter, the method of the present invention will be explained in detail based on the accompanying drawings 1 to 4 and examples showing the method of carrying out the method. First, FIG. 1 shows a vertical sectional view of the main parts of a speaker in an assembled state to which the method of the present invention is applied. In the figure, 1 represents a top plate, 2 represents a bottom plate, and 3 represents a magnet. There is. The mutual contact surfaces ₁ A ₃ and ₃ A ₂ of these parts 1, 2 and 3 are bonded together by the method of the present invention. In addition, in FIG. 1, 10 is a frame, 11 is a damper, 12 is a cone paper, and 13
is a packing, and 14 is a voice coil. The inventor has discovered that the mutual contact surfaces of the top plate 1, bottom plate 2, and magnet 3
To bond ₁ A ₃ and ₃ A ₂ , heat-activated elastomer adhesive is pre-coated on the parts 1, 2 and 3 to be bonded, and these are bonded to each other by induction or dielectric heating. When heat-compression bonding,
It has now been found that all the disadvantages and difficulties associated with conventional adhesive bonding assembly methods can be overcome. In addition, to implement this method, for example, a second
As shown in FIG. As shown in the figure, parts 1, assembled to magnet 3,
2 and 3 may be dielectrically or inductively heated under pressure using a high frequency current. Here, the heat-activated elastomer adhesive used in the method of the present invention has a basic composition of an adhesive made of a selected combination of phenolic resins that are compatible with diene rubber, and is treated with a play coat to provide a long-term , is characterized in that it enables heat-reactivated adhesion even if left unused. Next, in order to confirm that the heat-activated elastomer adhesive used in the method of the present invention is superior in various performances compared to conventionally used adhesives, we investigated adhesives having the basic composition as described above. The table shows the results of a comparative test of adhesion to various adherends using two types of formulation examples and three types of conventionally used adhesives.

[Table] In addition, the formulation examples of the adhesive, as well as the adhesion conditions and test conditions in this case are as follows. 1 Formulation Example (1) Formulation Example 1 Neoprene W (Showa Neoprene Co., Ltd.) 100 parts MgO (#150) 4 parts ZnO (No. 1) 5 parts Nibcil LP (Nihon Aerosil Co., Ltd.) 15 parts Noxel EUR (Shinko Ouchi) Chemical Co., Ltd.) 1 part SP 566 (Schenectaday) 100 parts Tamanol 528 (Arakawa Hayashi Sangyo Co., Ltd.) 20 parts Toluene 455 parts (2) Blend example 2 Neoprene AF (Showa Neoprene Co., Ltd.) 100 parts MgO (#150) 4 Part ZnO (No. 1) 5 parts Nipsil LP (Nippon Aerosil Co., Ltd.) 15 parts Noxel EUR (Ouchi Shinko Kagaku Co., Ltd.) 1 part SP 566 (Schenectaday Co., Ltd.) 100 parts Tamanol 528 (Arakawa Hayashi Sangyo Co., Ltd.) 20 parts Toluene 455 Part 2 Adhesion conditions (1) Application amount: 80-100μ (2) Heat activation: 170℃, 10 seconds, 2Kg/cm ² (using iron) However, as the epoxy resin, use the product name "CEMEDINE No. 1500". Main agent: hardening agent = 1:1
It was mixed, coated and crimped. As for acrylic resin, the product name is “CEMEDINE Y”.
-352A, B", agent A and agent B were applied separately to one side, and both sides were pasted and crimped. The adhesive area was 1 inch wide and 1/2 inch wrap. 3 Test conditions (1) Normal condition: After curing for 7 days at 20℃ and 65%RH,
Measurement of tensile shear strength (2) After curing for 7 days under cold and heat: 20℃ and 65%RH,
-40℃, 2Hrs and 100℃, 2Hrs are one cycle, and after 4 cycles, return to 20℃, 65%RH, and measure tensile shear strength (3) Softening point: 20℃, 65%RH, After curing for 7 days, a load of 500gv was fixed at the end of the specimen and the temperature was increased to 38℃.
Hold the temperature for 15 minutes at 4℃, adjust the temperature at a heating rate of 10 minutes, and measure the temperature when the load drops.However, the tensile rate for tensile shear strength is 50℃.
mm/min. From the results in the table, it can be seen that the absolute value of the tensile shear strength of the adhesive used in the method of the present invention is not necessarily greater than that of conventional adhesives, but is between the values for various adherends. It can be seen that there is no variation. Next, as the thermal activation conditions for the thermally activated elastomer adhesive used in the method of the present invention, the relationship between temperature and time is shown in the table below in terms of tensile shear strength.

[Table] The adhesion conditions and test conditions were the same as in the test, and the adherend was a chromate steel plate. From the table, it can be seen that the required tensile shear strength can be obtained if the temperature is 80°C to 185°C and the time is 5 seconds or more. Furthermore, heat aging tests were carried out under normal conditions and after heat activation, and the results are shown in the table.

[Table] The adhesion conditions and test conditions are the same as in the test. From the table, it can be seen that the heat-activated elastomer adhesive used in the present invention also excels in heat aging tests after heat activation. Based on the above results, it is found that when a heat-activated elastomer adhesive is applied to the assembly of magnetic circuit components of a speaker using the method of the present invention, dielectrically or dielectrically heated with a high-frequency current, and thermocompression bonded, it is possible to use the general method. For this purpose, it is appropriate that the temperature at the bonding point is 100°C to 170°C, the pressing time is 5 to 10 seconds, and the pressing force is 1 to 15 kg/cm ² . Next, examples of heat-activated adhesive assembly according to the method of the present invention will be described. Example: In the case of adhesion test to each material shown in the table, the composition or adhesive P was prepared in advance by
As shown in the figure, the adhesive surface of the bottom plate 2 is coated, and as shown in FIG. 3, the adhesive surface of the top plate 1 is also coated. After sufficiently volatilizing the organic solvent in the adhesive P applied in this way, the fourth
As shown in the figure, top and bottom plates 1,
Sandwich magnet 3 between 2 and cover the entire surface (diameter
100 mm) was subjected to dielectric or dielectric heating using high frequency while applying a pressure of 5 kg. The dimensions of each component used in this case are as follows. Magnet 3: Diameter 100mm Top plate 1: Diameter 95mm Bottom plate 2: Diameter 95mm The results of the drop test of the speakers thermocompressed in this way are shown in the table.

[Table] In the (1) normal drop test, top plate 1 and bottom plate 2 were spray-coated with adhesive P, and after curing them for 7 days at 20°C and 65% RH, magnet 3 was immediately applied. The material was heat-activated adhesively bonded to the material, returned to the temperature of 20°C and 65% RH, and then dropped 1m vertically. (2) In the normal state test after 1 month of plates, each plate 1 and 2 was cured for 1 month under play coat L at 20℃ and 65% RH, and then thermally activated and bonded to magnet 3. The test was returned to 65% RH and a 1m vertical drop was performed. Similarly, (3) the post-cooling/heating cycle test was conducted in the same way as the normal drop test, after curing for 7 days and thermally activated adhesion to the magnet 3, followed by one cycle of -40℃, 2Hrs → 100℃, 2Hrs, and 4 After the cycle, it was returned to the temperature of 20°C and 65% RH, and vertically dropped from 1 m. From the table, it can be seen that in the case of the method of the present invention, even if the parts to be bonded are precoated with adhesive and then cured for a considerable period of time and then thermally activated bonded, the bond strength will not be particularly affected. There can be no. As described above, according to the method of the present invention, the magnetic circuit of the speaker, which is composed of the top plate, bottom plate, magnet, etc., can be firmly bonded to each other without variation, and the bonding process can also be performed using high-frequency current. Productivity can be improved because thermocompression bonding can be carried out instantaneously using dielectric or induction heating.Furthermore, the product can sufficiently withstand repeated cold and hot loads, and there is no risk of cracks in the magnets, etc. , can withstand harsh conditions of use, and parts pre-coated with adhesive exhibit the desired adhesive strength even after being heat-activated bonded for a considerable period of time (2 to 3 months), making the speaker suitable for use. It can exhibit excellent effects such as giving flexibility to the manufacturing process. Although the method of the present invention has been described above with respect to the case of bonding the bottom plate and the magnet that constitute the magnetic circuit of a speaker, the method of the present invention is not limited to this, and will be applied to speakers in the future. In the assembly process, the use conditions are expected to become more severe as adherend materials become more diverse and difficult to adhere to, and the scope of use of speakers expands. Adhesives are capable of fully adapting to changes in materials and harsher usage conditions that are expected in the future, and therefore, the scope of application of the method of the present invention extends widely to these parts and fields. .

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of a speaker to which the method of the present invention is applied together with its magnetic circuit components;
Figures 2-4 are schematic diagrams illustrating the steps of the method of the invention. 1...Top plate, 2...Bottom plate, 3
...Magnet.

Claims (1)

[Scope of Claims] 1. In the magnetic circuit of an external magnetic speaker and an internal magnetic speaker, in which parts such as a top plate, a bottom plate, and a magnet are bonded to each other and are integrally constructed, the bonded portions of each component A heat-activated elastomer adhesive having the following composition is prepared in advance: Low crystalline polychloroprene 100 parts Magnesium oxide 4 to 8 parts Zinc oxide 3 to 5 parts Fine silicic acid 10 to 20 parts Vulcanization accelerator 1 A heat-activated elastomer adhesive having a composition of ~5 parts phenolic resin 80-150 parts toluene 400-800 parts is treated with a play coat, and after combining these play coated parts into a predetermined state, pressure is applied. 1. A method for assembling a magnetic circuit for a speaker, characterized by instantaneously thermocompressing a part to be bonded under dielectric heating or induction heating. 2. Even if the heat-activated elastomer adhesive is play-coated and left for a considerable period of time (2 to 3 months), the adhesion will not occur even if the temperature of the bonded area is 100° to 170°C, the time is 5 to 10 seconds, and the pressure is 2. The method for assembling a speaker according to claim 1, wherein the assembling method is performed at a rate of 1 to 5 kg/cm ² .