JPH0110914Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to an economical paper winding wire that increases the mechanical strength of coils for transformers, reactors, etc. Generally, in electrical equipment such as transformers and reactors,
It is often used in alternating magnetic fields created by self-coils or other coils. Therefore, in order to reduce the eddy current loss that occurs in the conductor due to this alternating magnetic field, the strands are divided into small pieces within the allowable range in terms of strength, and several of the paper-wrapped strands are bundled.
Furthermore, paper-wound wires commonly wound with insulating paper are commonly used. However, further conductor subdivision is desired to further reduce eddy current losses. However, the more the conductor is divided into smaller pieces, the more the conductor's space factor decreases due to so-called blisters caused by the insulating paper wrapped around the wires. Furthermore, when the mechanical strength of the conductor decreases and a short circuit generates a large current, the coil may be deformed due to the stress caused by the strong electromagnetic force generated. In order to prevent such a situation, it is practically advantageous to bond the finely divided conductors with an adhesive and integrate them. From this point of view, in the case of flat wires,
No. 28475, composite paper winding wire of Utility Model No. 17681, or composite insulated wire of Utility Model No. 57-43292,
Adhesive conductors using self-bonding materials have already been disclosed, such as the insulated wire of No. 26306. As shown in Figure 1, these adhesive conductors are made by stacking self-bonding rectangular enameled wires 1 in parallel and bonding them together with an insulator 2, heating and then cooling them. This results in an integrated adhesive conductor. However, compared to rectangular enameled wire without adhesive, self-bonding rectangular enameled wire coated with adhesive is considerably more expensive because it is coated with adhesive, so conventional wires as shown in Figure 1 are It has the disadvantage of being disadvantageous in terms of economy. However, in view of these drawbacks, this idea
The purpose of this invention is to provide a paper winding wire that has excellent mechanical strength and is inexpensive. This invention will be described below with reference to the embodiments shown in FIGS. 2 and 3. In FIG. 2, 1 is a self-bonding flat enameled wire made by coating a flat enameled wire with an adhesive, 3 is a flat enameled wire, and 4 is an insulating paper used to commonly wrap these wires. Further, F is the stress due to the electromagnetic force generated when a short circuit current occurs, and w is the position where the shear stress is maximum. By the way, the stress F and shear stress Fs applied to a bonded conductor A made by bonding a plurality of rectangular wires to each other are schematically shown in FIG. 4. When stress is applied in this way, the distribution of shear stress Fs becomes parabolic, with the largest value in the middle. In addition, the fourth
In the figure, 5 is a fulcrum. Therefore, when the number of rectangular wires is even as shown in Fig. 2, the two adjacent rectangular wires in the middle are used as the self-bonding rectangular enameled wire 1, which is made by applying adhesive to the rectangular enameled wire. , the others are flat enameled wire 3 with no adhesive applied and self-bonding flat enameled wire 1.
and arranged alternately. If the number of flat wires is odd, as shown in Fig. 3, one flat wire in the middle is used as a flat enameled wire 3 without adhesive applied.
In other cases, self-bonding rectangular enameled wires 1 and rectangular enameled wires 3 to which no adhesive is applied are arranged alternately. In the case of an odd number, by arranging the rectangular enameled wire 3 in the center, the number of relatively expensive self-fusing rectangular enameled wires 1 is reduced. In addition, in the case of an even number, the reason why the two adjacent rectangular wires in the middle are made into self-bonding rectangular enameled wire 1 is due to shear stress.
This is to increase the adhesive strength between the rectangular wires at the center where Fs is greatest. That is, the rectangular enameled wire 3
Due to the surface tension of the varnish, the enamel coating of
The corners are thicker. On the other hand, with respect to the self-bonding rectangular enameled wire 1, it is difficult to overcoat a thick layer of adhesive on the enamel coating, and the thickness of the adhesive layer is usually around 15 μm. Therefore, when the rectangular enameled wire 3 and the self-bonding rectangular enameled wire 1 are placed adjacent to each other, the thick corners of the enamel coating are bonded to each other, resulting in a bonding area sufficient to withstand large shear stress. Furthermore, it is difficult to obtain sufficient adhesive strength. Therefore, in this invention, the two adjacent rectangular wires in the middle with the largest shear stress Fs are bonded together as self-bonding rectangular enameled wires 1, thereby increasing the bonding area between them. This increases adhesive strength. Table 1 shows the results of a three-point bending test on a test piece in which a composite paper winding wire (the number of rectangular wires is as shown) as shown in FIG. 5 was bonded at 150° C. for 15 hours. A is the conventional one as shown in Fig. 1, B is the one according to this invention as shown in Fig. 2, and C is the arrangement in which the rectangular enameled wires 3 and the self-bonding rectangular enameled wires 1 are arranged alternately when the number of rectangular wires is even. Reference example 2 is based on this idea in Figure 3, and the size of one conductor is 1.4 mm thick.
It has a width of 6.0 mm and a length of 150 mm, and the distance between the supporting points for the three-point bending test is 100 mm. In addition, the bending test was performed using an autograph. The measurement temperature was 23°C.

[Table] In the table, a bending strength of 400 Kg/cm ² or more is a result when the test piece becomes "dog-shaped" and does not break at the bonded surface even if the strain is 20 mm or more. From the results shown in Table 1, it is recognized that the adhesive strength of the paper-wound wire of this invention is comparable to that of a paper-wound wire made only of self-bonding rectangular enameled wire. In particular, when the number of rectangular wires is even, as in the reference example in Fig. 5C, the rectangular enameled wire 3 without adhesive and the self-bonding rectangular enameled wire 1 coated with adhesive are simply alternated. The arranged one and the fifth
There is a clear difference between the bending strength of the reference example and that of the invention shown in Figure B, which is 370Kg/ ^cm2 , while the bending strength of the invention is more than 400Kg/ ^cm2 .
This clearly supports that by using the self-bonding flat rectangular enameled wire 1 as the two adjacent rectangular wires in the middle, a large adhesive strength can be obtained in the central portion as described above. As described above, according to this invention, all rectangular wires are made into self-adhesive rectangular wires by combining a rectangular enameled wire without adhesive and a self-adhesive rectangular wire coated with adhesive. Compared to the case of using enameled wire, there is an effect that a paper-wound wire can be obtained which is less expensive as the number of relatively expensive self-bonding enameled wires is reduced without substantially lowering the mechanical strength. Note that adhesives for self-bonding rectangular enameled wire include, for example, polyester, polyamide, phenoxy resin, and urethane resin, and examples of enamel include polyvinyl formal, polyester, and polyurethane.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a conventional composite insulated wire, FIG. 2 is a cross-sectional view showing one embodiment of this invention, and FIG. 3 is a cross-sectional view showing another embodiment of this invention. Figure 4 is a diagram to explain this idea, Figure 5
The figure is a cross-sectional view of a test piece subjected to a bending test. In each figure, the same reference numerals indicate the same or corresponding parts; 1 is a self-bonding rectangular enameled wire, 3 is a rectangular enameled wire, and 4 is an insulating paper.

Claims (1)

[Scope of utility model registration request] In a paper-wound wire made of multiple flat wires stacked in parallel and commonly wound with insulating paper, if the number of flat wires is even, two adjacent flat wires in the middle are coated with adhesive on the flat enamelled wire. The other parts are flat rectangular enameled wires with no adhesive applied and self-fusing rectangular enameled wires arranged alternately, and if the number of flat wires is odd, one in the middle is used. A paper-wound wire characterized in that the rectangular wire of the book is a rectangular enameled wire to which no adhesive is applied, and the other parts are alternately arranged self-bonding rectangular enameled wires and rectangular enamelled wires to which no adhesive is applied. .