JPS604571B2 - resin molded coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to resin molded coils for dry transformers, welders, instrument transformers, reactors, etc. that are molded using resin such as epoxy resin and polyester resin. The present invention relates to a method of forming an air duct for the coil.

Conventionally, the method of manufacturing resin-molded coils for use in dry-type transformers and the like has generally been to place a bare coil in a mold, and then pour resin into the mold.

For large-capacity coils, a manufacturing method was used in which a cooling air duct was formed inside the coil using a mold. However, in such a method, a large amount of work time is required for mold release processing, assembly, mold disassembly after resin hardening, and maintenance.

In addition, it takes a long time for the resin to harden, and the mold cannot be reused during this time, so many molds are required, and in the case of models with many specifications, such as dry type transformers, expensive molds are required. I had to prepare a lot. Now, the following method has already been devised for the purpose of solving such manufacturing problems, simplifying the manufacturing process, and providing a high-performance resin molded coil.

This method does not use a mold, and it also solves the problem of deterioration of electrical and mechanical properties due to resin leakage, which occurs when impregnated or injected resin is heated and cured without using a mold. This is the ideal method. When this method is used to heat and harden a coil impregnated or injected with resin, the coil surface is irradiated with ultraviolet rays while rotating the impregnated coil to form a leak-proof film (this impregnated or injected resin contains a composition that is cured by ultraviolet rays.) After that, it is further heated and cured. According to this method, the above-mentioned problems were solved, and even coils that were impregnated with a large amount of resin and were very prone to leaking, such as dry type transformers and voltage transformers, could be manufactured without any problems. However, as the capacity of the coil increases, its volume increases and the outer circumferential surface of the coil alone is insufficient to dissipate the internal heat generated during operation.In order to deal with this problem, it is easy to consider installing an air duct inside the coil. However, as shown in Figure 1, methods for forming ducts on the inner insulation 2, such as duct forming methods for varnish-immersed dry type transformers and oil-immersed transformers, are used. The conductor 3 is wound closely from one end to form a conductor layer, and the duct piece 4 is placed on top of the conductor layer.
In the method in which the conductor 3 is further wound to form a conductor layer and an air duct is formed between the conductor layers, the surface of the conductor layer facing the duct piece is in direct contact with air, which is one of the most important performance characteristics of a resin molded coil. The disadvantage was that the moisture resistance and dust resistance, which are the main characteristics, were impaired.

The present invention has been made for the purpose of providing a resin-molded coil without using a mold as described above, which has a duct having excellent moisture resistance and dust resistance.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, embodiments of the method according to the invention will be explained with reference to the drawings.

FIG. 2 shows a plan view of a resin molded coil according to the present invention, and FIG. 3 shows a sectional view thereof. In the figure, 1 is a resin molded coil, 2 is an inner insulating layer wound around the innermost circumference of the coil, 3 is a conductor closely wound on the inner insulating layer 2, and 4 is an intervening conductor layer. A duct piece for forming an air duct, 5 is a duct insulating layer formed on both sides of the duct in contact with the conductor layer, and 6 is a duct piece formed around the outermost periphery of the conductor wound in a predetermined number of layers. This is the outer insulating layer. Furthermore, 7 is an end side insulation formed at both ends of the conductor layer, 8
A feature of the invention is the insulating padding enclosed between the duct pieces on either side of the portion where the conductor is transferred across the duct. Next, the construction procedure of the resin molded coil of this example will be explained.

After a metal cylindrical winding core (not shown) is subjected to a suitable release treatment, this winding core is attached to a winding machine. In order to form the inner insulating layer 2, predetermined insulating materials such as glass cloth, aromatic polyamide paper, polyester non-woven fabric, etc., which are easily soaked in resin, are wrapped around the outer periphery of the core multiple times, singly or in combination. After that, the conductive wire 3 is wound closely with a predetermined insulation dimension left at the end of the coil, and then a plurality of strips of insulating material cut to a predetermined dimension are stacked on both sides of the conductor layer, and the conductor 3 An end insulation 7 having a thickness approximately equal to that of the end insulation 7 is inserted. Next, the conductor 3 is transferred to the next layer on the conductor layer and the end side insulation through an insulator in which a duct piece 4 is arranged at an appropriate interval between two predetermined duct insulations 5, Furthermore, after forming a conductor layer in which the conductor was closely wound and end-side insulation, a predetermined insulating material was wound around the outermost periphery of these coils a plurality of times to form an outer insulating layer 6. Note that the same materials as those for the inner insulating layer 2 were used for the end side insulating layer 7 and the outer insulating layer 6. A polyester mat was stuffed between the duct pieces 4 at the portion where the conductor 3 was transferred across the duct to completely embed the conductor to be transferred, thereby completing an elementary coil. Then, a resin-molded coil was obtained from this raw coil by the method described above without using a mold. As is clear from the above, the conductor in the duct part, which was conventionally exposed directly to the air, is completely embedded in resin, and the coil is completely dust-proof even if it has a duct.
It has a moisture-proof structure. In the above embodiment, a polyester mat was used as the filler around the conductor that crosses the duct, but other fibrous mats such as aromatic polyamide fibers and glass fibers may be used, or inorganic fillers such as silica may be encapsulated. In addition, high viscosity synthetic resins having chicken tropic properties are also effective and have good workability. Furthermore, in the above embodiment, a coil impregnated with resin and molded was described, but it is also a resin molded coil using prepreg that has been pre-immersed in resin to a semi-hardened state for the inner insulation, duct insulation, outer insulation, and end side insulation. However, the same effects as in the above embodiment can be achieved.

As described above, according to the present invention, since the area between the duct pieces where the conductor moves across the duct is completely embedded in resin, it has excellent green resistance, dust resistance, and heat dissipation efficiency. This has the effect of providing a resin-molded coil with a good air duct.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a conventional example, FIG. 2 is a plan view of a resin molded coil showing an embodiment of the present invention, and FIG. 3 is a front view in cross section taken along line AA in FIG. In the figures, the same symbols indicate the same or corresponding parts, 1 is a resin molded coil, 2 is an inner insulating layer, 3 is a conductor, and 4 is a resin molded coil.
is a duct piece, 5 is a duct insulation layer, 6 is an outer insulation layer,
7 is end side insulation, and 8 is stuffing. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. In a resin molded coil having a conductor layer formed by winding a conductor multiple times and a duct formed between the conductor layers with a plurality of duct pieces interposed therebetween, at least the duct pieces on both sides of the conductor crossing the duct 1. A resin-molded coil characterized in that at least a portion of the duct is filled with an insulator to embed a conductor that crosses the duct. 2. The resin molded coil according to claim 1, wherein the insulator filled between the duct pieces is a high viscosity synthetic resin.