JP2005205815A - Manufacturing method for electrical machinery equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain electrical machinery equipment having excellent heat dissipation properties and a high mechanical strength and being free of cracking. <P>SOLUTION: An electrical machinery component is set in a casting mold 1. Then, a filling material 4 in the state of particles is filled as an inorganic filling material in the casting mold and a defoamed thermosetting resin composition 5 is cast thereinto in vacuum and cured. Thereby the electrical machinery equipment molded with the resin is manufactured. A fibrous filling material 3 is added to the inorganic filling material. The fibrous filling material is short fibers or cloth and it is constituted of at least one kind of glass, alumina, silica, aluminum nitride, silicon nitride, boron nitride, silicon carbide or magnesium oxide. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an electrical device having excellent heat dissipation and mechanical strength.

2. Description of the Related Art In recent years, heat generation during operation has become a major problem with coil devices such as electric motors and transformers, and semiconductor devices such as power modules and LSIs as their size, density, and output increase. This is because there is a problem of destabilization of device and device characteristics due to heat generation and deterioration of life, and coils and semiconductors are sealed in order to prevent the temperature from rising beyond the limit temperature. It is important to increase the thermal conductivity of the mold resin and dissipate heat efficiently.
A well-known method for solving this problem is that a thermosetting resin composition in which an electrical component such as a coil is set in a casting mold and highly filled with an inorganic filler having a high thermal conductivity is usually used. It is a method of injecting and curing under pressure or vacuum. However, increasing the blending amount of the inorganic filler significantly increases the viscosity of the thermosetting resin composition, which makes it difficult to cast, so there is a limit to the blending amount of the inorganic filler. was there.
In addition, as another conventional example, in a casting mold containing an electrical component such as a coil, a particulate filler such as silica is previously placed, and a thermosetting resin composition is injected and cured under vacuum in this method. Yes (see, for example, Patent Document 1). In this method, since the inorganic filler is previously placed in the casting mold, the viscosity of the thermosetting resin composition can be lowered. Therefore, it is possible to increase the filling rate of the inorganic filler, and it is possible to improve the heat dissipation property of the electrical equipment.
Japanese Patent Laid-Open No. 08-1224779

However, as in the method described in Patent Document 1, when the particulate filler is filled at a high density, the amount of the resin is not reduced accordingly, resulting in a decrease in toughness. After curing, there is a problem that cracks are likely to occur when a heat cycle or mechanical impact is applied.
Therefore, the present invention has been made in view of such problems, and an object thereof is to provide an electrical device that is excellent in heat dissipation, has high mechanical strength, and does not generate cracks.

In order to solve the above problems, the present invention is configured as follows.
The invention according to claim 1 is a thermosetting resin in which an electric part is installed in a casting mold, and then a particulate filler as an inorganic filler is filled in the casting mold, and then defoamed. The composition is cast and cured under vacuum, and a resin-molded electrical equipment manufacturing method is obtained by adding a fibrous filler to the inorganic filler.
According to a second aspect of the present invention, the fibrous filler is a short fiber.
According to a third aspect of the present invention, the fibrous filler is made into a cloth.
According to a fourth aspect of the present invention, the fibrous filler is at least one of glass, alumina, silica, aluminum nitride, silicon nitride, boron nitride, silicon carbide, or magnesium oxide.
According to a fifth aspect of the present invention, the particulate filler is at least one of glass, alumina, silica, aluminum nitride, silicon nitride, boron nitride, silicon carbide, or magnesium oxide.
In a sixth aspect of the present invention, the particle filler has a particle size of 200 μm to 1000 μm.
The invention according to claim 7 is an electrical device obtained by the manufacturing method according to any one of claims 1 to 6.

According to the first aspect of the present invention, since the fibrous filler is filled in addition to the particulate filler, the mechanical strength can be greatly improved. Therefore, it is possible to prevent cracks occurring in the product when it is cured or when a heat cycle or mechanical impact is applied after curing. In general, when a thermosetting resin composition is prepared using a fibrous filler, the viscosity is greatly increased compared to the case where a particulate filler is used, and castability is impaired. Since the fibrous filler is put in the casting mold in advance, the castability is not impaired.
According to the second aspect of the invention, since the fibrous filler is a short fiber, the mechanical strength of the cast cured product can be improved. Moreover, since the short fiber is previously placed in the casting mold, the casting property is not impaired. In addition, short fibers tend to form a continuous heat dissipation network between fillers as compared to particulate fillers. This is effective in improving thermal conductivity, and heat generated during curing is easily dissipated into the mold and the atmosphere, making the curing reaction more uniform and effective in preventing cracks.
According to the invention described in claim 3, since the fibrous filler is made of cloth, a two-dimensional network structure can be formed, and the mechanical strength of the cast cured product can be greatly improved. In addition, since a continuous heat dissipation network is built, the thermal conductivity is improved and the heat generated during curing is easily dissipated into the mold and the atmosphere, making the curing reaction more uniform and effective in preventing cracks. is there.
According to the invention described in claim 4, since the inorganic compound having high thermal conductivity is used as the fibrous filler, the heat dissipation can be improved, and the crack prevention is effective.
According to the invention described in claim 5, since the inorganic compound having a high thermal conductivity is used as the particulate filler, it is possible to improve the heat dissipation and to prevent cracks.
According to the invention described in claim 6, since the particle size of the particulate filler is 200 μm to 1000 μm, it is possible to prevent an increase in pressure loss when casting the thermosetting resin composition. As a result, it is possible to inject the thermosetting resin composition uniformly without any gaps between fillers and parts, so that the mechanical strength is improved.
According to the seventh aspect of the present invention, it is possible to obtain an electrical device that has excellent heat dissipation, high mechanical strength, and no occurrence of cracks.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a process diagram showing a method for manufacturing a linear motor movable element which is an electrical apparatus of the present invention. In the figure, 1 is a casting mold, 2 is a linear motor armature with a coil attached, 3 is a fibrous filler, 4 is a particulate filler, 5 is a thermosetting resin composition, and 6 is a linear motor mover. It is.
As the fibrous filler 3, four types of glass cloth (manufactured by Unitika Glass Fiber Co., Ltd.), alumina cloth, silica cloth, and glass fiber were used. In addition, the thing which does not add the fibrous filler 3 was also used as a comparative example. As the particulate filler 4, silica having a particle diameter of 200 to 400 μm (manufactured by Denki Chemical Co., Ltd.) was used. As a comparative example, silica having a particle size of 100 to 200 μm was used (Sample No. 5). The thermosetting resin composition 5 uses 100 parts of bisphenol F type epoxy resin (Dainippon Ink Chemical Co., Ltd., trade name: Epicron 830) and phenyl glycidyl ether (manufactured by Nagase ChemteX Corporation), trade name: Denacol. EX141) 5 parts and boron trifluoride monoethylamine (manufactured by Stella Chemifa Co., Ltd.) 7 parts were added and mixed uniformly to obtain an epoxy resin composition (Sample Nos. 1 to 6).
Table 1 shows the types of samples in which the fibrous filler and the particulate filler are combined. Samples Nos. 1 to 4 are in this example, and Samples Nos. 5 and 6 are comparative examples.
Next, a manufacturing method of the linear motor movable element of sample No. 1 of this example will be described.
As shown in FIG. 1, in step 1, an armature 2 and a fibrous filler (glass cloth) 3 were installed in the casting mold 1. At this time, one fibrous filler (glass cloth) 3 was arranged on each side of the armature 2 in parallel with the armature 2.
In step 2, a particulate filler (silica) 4 having a particle size of 200 to 400 μm is vibrated into the casting mold 1 in the casting mold 1 in which the armature 2 and the fibrous filler (glass cloth) 3 are accommodated. Filled while giving.
In step 3, the previously prepared epoxy resin composition 5 is heated to 80 ° C. and then defoamed. This is made up of armature 2, fibrous filler (glass cloth) 3, and particulate filler (silica) 4. The casting mold 1 was cast under vacuum.
In step 4, after casting, this was heated and cured at 150 ° C. for 15 hours to complete the mover 6 of the linear motor.
Next, the crack characteristics of the manufactured linear motor movable element 6 were examined. The evaluation method was performed by subjecting the linear motor movable element 6 to 200 cycles of a cooling cycle of −50 ° C. for 4 hours and 130 ° C. for 4 hours, and examining the occurrence of cracks.
As shown in Table 1, no crack was generated even after 200 cycles, and the heat cycle property was good. (The result of the test is ◯ when no crack is generated, △ when slightly cracked, and × when markedly cracked.)

  Sample No. 2-4 in this example was obtained by changing the types of the particulate filler 4 and the fibrous filler 3 as shown in Table 1. For sample Nos. 2 and 3, alumina cloth and silica cloth were used as the fibrous filler 3, and the other conditions were the same as those of sample No. 1. Sample No. 4 was prepared by mixing 5 parts of glass fiber 3 with 70 parts of silica 4 having a particle size of 200 to 400 μm, and uniformly mixing the casting mold 1 with vibration. . Thereafter, the epoxy resin composition 5 was cast and cured in the same manner as Sample No. 1.

Next, as with sample No. 1, the crack characteristics of the manufactured linear motor movable element 6 were examined. As a result, none of the linear motor movable elements 6 of Sample No. 2-4 were cracked after 200 cycles, and the heat cycle performance was good.
In contrast to the examples of the present invention, sample No. 5 of the comparative example uses silica having an average particle size of 100 to 200 μm as the particulate filler 4, but significant cracks were observed. This is presumably because the particle size of the particulate filler 4 is too small, the castability of the thermosetting resin composition 5 is poor, and there are many unimpregnated portions of the resin. Accordingly, the particle size of the particulate filler 4 needs to be 200 μm or more, and in order to fill a gap such as a coil, it needs to be 1000 μm or less. Moreover, although sample No6 of the comparative example was only the particulate filler 4 and did not use the fibrous filler 3, although it was slight, generation | occurrence | production of the crack was recognized.

In this example, bisphenol F type epoxy resin was used as the main component of the thermosetting resin composition 5, but other epoxy resins such as bisphenol A type epoxy resin and cresol novolac type epoxy resin may be used.
In addition, boron trifluoride monoethylamine was used as the curing agent, but it is possible to use a wide range of commonly used epoxy resin curing agents such as acid anhydride curing agents, amine curing agents, and imidazole curing agents. it can. Moreover, various hardening accelerators can also be used together as needed.
Moreover, various additives, such as a diluent, a coupling agent, and a coloring agent, can be used together, and you may use together an inorganic filler.
In this embodiment, one glass cloth 3 is arranged on each side of the armature 2, but this is not particularly limited, and a plurality of glass cloths 3 may be arranged as necessary in consideration of space and the like. You can also. Also, the arrangement method may be arranged perpendicularly or randomly with respect to the armature 2, or the glass cloth 3 may be shortened and dispersed throughout.
Moreover, although the crushed thing was used as the shape of the particulate filler 4, a spherical thing can also be used.

Flow chart showing the manufacturing process of the present invention

Explanation of symbols

1 Casting mold 2 Armature 3 Fibrous filler (glass cloth)
4 Particulate filler (silica)
5 Thermosetting resin composition (epoxy resin composition)
6 Linear motor mover

Claims (7)

Electrical parts are installed in the casting mold, and then the filler is filled with a particulate filler as an inorganic filler. The defoamed thermosetting resin composition is cast under vacuum. In the manufacturing method of the electrical equipment that is cured and resin molded,
The manufacturing method of the electric equipment characterized by adding the fibrous filler to the said inorganic filler.   The method for manufacturing an electrical device according to claim 1, wherein the fibrous filler is a short fiber.   The method for manufacturing an electrical device according to claim 1, wherein the fibrous filler is a cloth.   The said fibrous filler consists of at least 1 sort (s) of glass, an alumina, a silica, an aluminum nitride, a silicon nitride, a boron nitride, a silicon carbide, or magnesium oxide, The any one of Claim 1 to 3 characterized by the above-mentioned. The manufacturing method of the electric equipment of description.   The particulate filler is made of at least one of glass, alumina, silica, aluminum nitride, silicon nitride, boron nitride, silicon carbide, or magnesium oxide, according to any one of claims 1 to 4. The manufacturing method of the electric equipment of description.   6. The method of manufacturing an electrical equipment according to claim 1, wherein a particle size of the particulate filler is 200 μm to 1000 μm.   An electric device obtained by the method for manufacturing an electric device according to any one of claims 1 to 6.

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