JP3047682B2 - Mold coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded coil such as a ground coil for a magnetically levitated railway.

[0002]

2. Description of the Related Art For example, a magnetic levitation type ground coil for a railway is attached to a guideway and is used in all weather. Therefore, the conductor coil is used in a severe environment such as being exposed to wind and rain and being exposed to ultraviolet rays from direct sunlight. For example, as disclosed in JP-B-56-5094, a conductor coil is formed by SMC (sheet molding compound). A structure molded with FRP (fiber reinforced plastic) is adopted.

In other words, the purpose of the FRP molding of the ground coil is to insulate the conductor coil, improve the rigidity against mechanical stresses such as electromagnetic force, improve rigidity, and protect the weather resistance. Generally, the SMC is heated in consideration of mass productivity.・ Pressure molding is adopted.

[0004] SMC is a sheet-like resin in which a filler such as glass fiber and calcium carbonate powder is mixed with a resin such as polyester and the like, and is disposed around a conductor coil, and is heated and pressed. It has good electrical and mechanical properties.

However, when a resin-molded ground coil is used outdoors for a long period of time, the resin in the surface layer is deteriorated by ultraviolet rays, causing a choking (separation) phenomenon of the resin and the resin powder to be scattered. . In particular, it has been found that there is a case where the glass fiber in the mold resin may be scattered in a portion where deterioration is severe.

As a conventional technique for preventing the deterioration of weather resistance due to the above-mentioned ultraviolet rays or the like, (1) a weather-resistant paint such as a fluorine-based paint, acrylic, or acrylic urethane is applied to the outer surface of a molded coil (molded product). Apply or (2)
Either polyester film, non-woven fabric, polypropylene film, etc. can be integrally molded with the mold coil,
(3) As disclosed in Japanese Patent Application Laid-Open No. 3-215909, various techniques such as a technique of forming a silicone rubber reinforcing film on the surface of a molded article have been adopted or studied.

[0007]

However, among the techniques for preventing the deterioration of weather resistance as described above, when silicone rubber is used as a reinforcing film as in the method (3), the silicone rubber is sprayed on the exterior surface. Although it has excellent buffering properties against sand and dust, it is technically difficult to form a thin film or make it uniform in thickness when applying silicone rubber by applying or dipping it. The thickness accuracy of the coil (for example, in the case of a molded coil such as a ground coil for magnetic levitation, an accuracy within ± 0.5 mm is required for the thickness of the molded coil of 50 mm from the viewpoint of ride comfort). Difficult to maintain. In addition, when the surface of the molded coil is made of silicone rubber, the rigidity of the entire molded coil is reduced, so that the stress of the FRP is also increased, and the mechanical strength of the molded coil is likely to be reduced. That is, originally, the rigidity of the surface of the molded coil is
It must be high to withstand external forces such as electromagnetic force and train wind pressure, and cannot meet this requirement.

In this respect, the prior arts (1) and (2) can reduce the thickness of the protective film on the outer surface of the molded coil and increase the rigidity of the outer surface of the molded coil.
When applying a fluorine-based paint or the like to the outer surface of the mold coil as in (1), the paint itself is weak in bonding properties, and if there is an external impact on the surface of the mold coil, the paint is easily peeled and the maintenance burden is increased. There is a problem that grows,
Materials such as (2) have a problem that the weather resistance of the film itself is not sufficient.

[0009] As described above, none of these is considered to be sufficient for the long-term use of the ground coil for a magnetically levitated railway as a transportation means, and a countermeasure is required.

The present invention has been made in view of the above points, and an object of the present invention is to provide a molded coil which is installed under severe environmental conditions such as outdoors, such as the above-mentioned ground coil, in terms of thickness accuracy, mechanical strength, long-term weather resistance and impact resistance. An object of the present invention is to provide an excellent molded coil that can satisfy all of the requirements.

[0011]

In order to achieve the above object, the present invention provides a molded coil in which a conductor coil is molded from a plastic (for example, FRP) mixed with a reinforcing material. Then, a composite sheet formed by laminating and bonding a fluorine-based resin film and a fibrous material is integrally formed with the molded article so that the fluorine-based resin film is on the outside.

Here, as the fluorine-based resin film,
PVF (polyfluorinated vinyl), PVDF (polyvinylidene fluoride), ETFE (ethylene-tetrafluoroethylene copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), PFA (tetrafluoroethylene-perfluoro) Alkoxyethylene copolymer), PTFE (polytetrafluoroethylene) and the like. Among them, PVF, PVDF, ETF
E is a more preferable material because a simple corona discharge treatment can be used in the treatment method for improving the adhesion performance.

When ultraviolet rays are transmitted through the fluororesin film, the adhesive is degraded. Therefore, instead of forming a transparent clear film, an ultraviolet absorber is added or the film itself is made into a color film, so that the inside of the film is made transparent. It is important to minimize the effects of ultraviolet light on the environment.

Examples of the fiber material include glass cloth, glass non-woven fabric, polyester cloth, polyester non-woven fabric and the like.

If the composite sheet of a fluororesin film and a fibrous material has a complicated molded product, simply placing a flat composite sheet in a molding die and performing molding will result in a complicated shape. In the case where the film stretches and extremely thin parts are generated extremely, and the intended weather resistance protection is impossible, or the occurrence of wrinkles causes the film to overlap, the composite sheet It is preferable to use a preform that has been preliminarily adjusted to the shape of a molded article in a state in which the preform is heated near the softening point of the fluororesin in advance.

[0016]

According to the above construction, by integrating the mold coil (molded product) and the composite sheet, the resin of the mold coil is adhered to the fiber material in the composite sheet by impregnation, and the fiber material becomes one of the mold coils. Parts, as a result, the substantial thickness of the protective film formed on the outer surface of the molded coil is only a fluororesin film,
The thickness of the protective film can be reduced, and the thickness accuracy of the entire molded coil can be kept good and uniform.

Moreover, the fibrous material in the composite sheet becomes a part of the molded coil as described above, and the fluororesin film is firmly adhered to the surface of the molded coil through the fibrous material. Can prevent the fluororesin film from peeling off even if the impact is applied, and improve the impact resistance. Furthermore, the above-mentioned fluororesin film has a higher purity of the material itself than a fluororesin paint (in the case of a paint,
The purity is lowered due to the addition of an additive or the like for enhancing the adhesion to the object to be coated.) The higher the purity, the better the weather resistance and, even when exposed to ultraviolet rays, can greatly reduce the effects of ultraviolet rays. It can exhibit the characteristic of.

Further, by using the fluorine-based resin film on the outer surface of the molded coil, the rigidity of the molded coil can be increased and the mechanical strength can be increased.

Further, when the shape of the surface of the molded coil is complicated, the composite sheet is preformed in advance according to the surface shape, so that the thickness of the film is not greatly reduced and wrinkles are not generated. A film layer having good adhesion to the film is obtained.

Since the choking phenomenon of the resin of the molded coil due to the deterioration of the weather resistance is mainly caused by the ultraviolet rays, it is needless to say that the composite sheet of the fluororesin film and the fiber material is unnecessary in the portions not exposed to the ultraviolet rays.

[0021]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1A is a perspective view of a molded coil according to an embodiment of the present invention, and illustrates a ground coil for a magnetic levitation type railway as an example, and FIG. −
FIG. 2C is a cross-sectional view of the composite sheet to be a surface protective film, taken along a line A.

In these figures, reference numeral 1 denotes a coil formed by winding a conductor.
Is heated and pressurized to form a molded coil 5, and a composite sheet 3 described below is integrally formed on one surface (the side exposed to solar radiation) of the molded coil (molded product) 5.

As shown in FIG. 1C, the composite sheet 3 is formed by laminating a fluororesin film 3a and a fiber material 3c and bonding them with an adhesive 3b. ETFE film as 3a,
A polyester nonwoven fabric is used as the fiber material 3c, and an epoxy adhesive is used as the adhesive 3b.

First, one surface of the fluororesin film 3a is subjected to corona discharge treatment, an epoxy adhesive 3b is applied to this surface, and then the fiber material 3c is laminated through a laminating roll and heat-cured to cure the composite sheet 3a. I got Further, in this embodiment, the composite sheet 3 is preheated to 150 ° C. in advance, preformed with a mold according to the surface shape of the mold coil 5, and formed into a mold at the time of SMC molding (mold coil molding). By setting
It is integrally formed with P (resin mold) 2. After that, the mounting holes 4a to 4j are formed in the molded coil 5.

Here, the thickness of the fluororesin film 3a is desirably 20 to 100 μm from the viewpoint of the shape followability and the maintenance of weather resistance by the above-described preform.

The metal sodium treatment or corona discharge treatment performed on the surface of the fluororesin film 3a for improving the adhesiveness of the adhesive must be performed so that the surface tension after the treatment is 35 dynes or more.

As exemplified in the means for solving the problem, there are various types of fibrous materials 3c. However, there are various types of fibrous materials 3c from the viewpoint of adhesiveness with the adhesive 3b to be used and affinity with the resin of FRP as the mold resin 2. Select. The treatment of the adhesive 3b is desirably minimized in order to increase the adhesiveness of the resin of the FRP2 during molding.

When performing the preform of the composite sheet 3 described above, it is desirable to use a nonwoven fabric having good followability with the mold as the fibrous material 3c. If a nonwoven fabric is used, the smoothness of the finished surface of the molded product is also good.

The adhesive 3b is not particularly limited. In addition to the epoxy type, the adhesive 3b may be based on the affinity with a fiber base material such as a polyester type, an organic siloxane type, a polyurethane type, or a FRP resin. Can be selected.

The type of FRP2 is not particularly limited, and it is considered that the present invention can be applied to all types molded with a molding die. Examples of the molding method include SMC and RTM (resin transfer molding).

When the FRP molded coil is manufactured by the above-described method, during the SMC molding operation, the surface of the fluororesin film (here, the ETFE film) in contact with the outer mold has good releasability. The mold operation was extremely good as compared with general SMC molding in which the composite sheet 3 was not integrally molded.

The adhesive strength between the composite sheet 3 of the molded article and the mold resin portion 2 was confirmed by a 180 mm peel test at 25 mm.
The FE film 3a and the nonwoven fabric 3c exhibited a strong adhesive force of 2.4 kgf.

Next, in order to investigate the weather resistance of the integrally molded product, a molded plate having a thickness of 5 mm in which the composite sheet 3 and the mold resin 2 are integrally molded as in the case of the FRP molded coil is manufactured, and the molded product is cut. E with sunshine weather meter
A weather resistance test for exposing the TFE film surface side was performed for 1500 hours. In this test, for comparison, a molded plate of only SMC (Comparative Example 1), an SMC molded plate integrally molded with a polyester nonwoven fabric (Comparative Example 2), and ETFE having one surface subjected to corona discharge treatment were integrally molded without using a fiber material. An SMC molded plate (Comparative Example 3) was also tested at the same time. Table 1 shows the measurement results of various characteristics before and after the exposure test by the sunshine weather meter. It is clear that the one according to the invention has excellent weather resistance.

[0035]

[Table 1]

Further, according to the present embodiment, the resin of FRP2 is bonded to the fiber material 3c in the composite sheet 3 by impregnation so that the fiber material 3c becomes a part of the mold coil 5, and as a result, the mold coil 5. The substantial thickness of the protective film formed on the outer surface is only the fluorine-based resin film 3a, and the protective film can be made thinner, and the accuracy of the entire thickness of the molded coil can be kept good and uniform.

[0037]

As described above, according to the present invention,
An excellent mold coil that can satisfy all of the thickness accuracy, mechanical strength, long-term weather resistance, impact resistance, etc. of a molded coil installed in severe environmental conditions such as outdoors like a magnetic levitation type ground coil for railways Can be provided.

[Brief description of the drawings]

1A is a perspective view of a molded coil according to an embodiment of the present invention, FIG. 1B is a cross-sectional view taken along the line AA, and FIG. 1C is a partial cross-sectional view of a composite sheet used in the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Coil, 2 ... Fiber reinforced plastic (mold resin), 3 ... Composite sheet, 3a ... Fluorine resin film,
3b: adhesive, 3c: fiber material, 5: FRP molded coil

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Ikushi Kano 3-1-1, Sachimachi, Hitachi-City, Ibaraki Pref. Inside the Hitachi Works, Hitachi, Ltd. (72) Yoshihiro Haraguchi 3-1-1 Sachimachi, Hitachi-City, Ibaraki No. 1 Inside Hitachi, Ltd. Hitachi Plant (72) Inventor Tomoya Tsunoda 3-1-1, Sakaimachi, Hitachi, Ibaraki Prefecture Inside Hitachi, Ltd. Hitachi Plant (72) Inventor Junji Uchiyama Name of Nakamura, Nagoya City, Aichi Prefecture Station No. 1-4, Tokai Passenger Railway Co., Ltd. (72) Inventor Hiroshi Ariga 3-474-2 Tsukakoshi, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Asahi Glass Co., Ltd. 1-70-2 Inahei, Ichi-city 2 Kotobuki Murayama Plant (58) Fields surveyed (Int. Cl. ⁷ , DB name) H01F 7/20 H01F 7/06

Claims (3)

(57) [Claims] In a molded coil in which a conductor coil is molded from plastic mixed with a reinforcing material, a composite sheet formed by laminating and adhering a fluororesin film and a fiber material to at least one surface of the molded product is provided. A molded coil formed integrally with the molded body so that the fluorine-based resin film faces outward. 2. The molded coil according to claim 1, wherein the plastic is a fiber reinforced plastic. 3. The composite sheet according to claim 1, wherein the composite sheet is preliminarily heated and formed at a temperature near a softening point of a fluorine-based resin film in accordance with the outer shape of the molded body. A molded coil characterized by being integrally molded.