JPS633404B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for manufacturing a rectangular enameled wire. In manufacturing rectangular enameled wire, it is desirable to apply and bake enamel paint to a uniform thickness on the flat surface, edge surface, and corner portions of the rectangular conductor, but in reality, changes in the viscosity of the enamel paint, surface tension effects, and resin It is extremely difficult to coat and bake to a uniform thickness due to curing shrinkage and other factors. For this reason, in the method of manufacturing rectangular enameled wires, rectangular enameled wires are likely to be produced which have different coating thicknesses on the flat surface, edge surface, and corner portions. Among rectangular enameled wires that have different coating thicknesses on the flat surface, edge surfaces, and corners, rectangular enamelled wires with significantly uneven coatings on the flat surface have a large gap between the wires when wound into electrical equipment coils. This has the disadvantage that the coil space factor is significantly reduced. Another drawback of this type of rectangular enameled wire is that it has poor coil windability because the coating thickness on the flat surface is uneven. The purpose of the present invention is to provide a novel method for manufacturing a rectangular enameled wire that can eliminate the drawbacks of the prior art described above and improve the coil space factor by eliminating the unevenness of the coating on the flat surface. It is something. That is, the gist of the present invention is to correct the unevenness of the enamel film on the flat surface of a rectangular enameled wire obtained by coating and baking an enamel paint on a rectangular conductor by rolling it to correct the unevenness within a rolling reduction ratio of 0.5 to 15%. Here, the rolling reduction is the value calculated as rolling reduction = a-b/a x 100, where a is the maximum finished dimension in the flat direction before straightening rolling, and b is the finished dimension in the flat direction after straightening rolling. It is. The reason why the rolling reduction is set in the range of 0.5 to 15% in the present invention is as follows. In other words, the rolling reduction ratio is 0.5
% or less, the straightening rolling has no effect and the unevenness of the film on the flat surface cannot be eliminated. On the other hand, the reason why the rolling reduction is 15% or less is because if the rolling reduction is 15% or more, the appearance of the enamel film will change significantly, and the mechanical properties of the rectangular enameled wire, especially the elongation properties of the enamel film, will be significantly reduced. Next, the present invention will be explained with reference to the drawings. FIG. 1 shows a cross-sectional view of a rectangular enamelled wire produced by a conventional method, and shows that the coating on the flat surface is extremely uneven. FIG. 2 shows a cross-sectional view of a rectangular enamelled wire manufactured with the dimensions of the present invention, and shows that the unevenness of the film on the flat surface has been eliminated. FIG. 3 is a schematic diagram showing an example of the method for manufacturing a rectangular enameled wire according to the present invention. The round conductor 1 fed out from the conductor feeding bobbin 3 passes through a guide pulley 4 and enters a rolling roll 5, where it is rolled into a rectangular conductor of a predetermined size. Next, the rolled rectangular conductor enters an annealing furnace 6 to be annealed, and then is guided into an enamel paint tank.
Enamel paint is applied, then excess paint is squeezed out with a die 8, and the wire is baked in a baking oven 9 to form a rectangular enameled wire. Next, this rectangular enameled wire is guided by a straightening roll 10, straightened and rolled at a reduction rate of 0.5 to 15%, and finally wound onto a winding bobbin 11. Comparative examples using the conventional method and examples using the method of the present invention are shown below. Comparative example 1 A round copper wire with a conductor diameter of 0.45mmφ was rolled using a rolling roll.
After forming a rectangular copper wire of 0.23 x 0.70 mm, it is introduced into an annealing furnace and annealed. Next, an enamel paint was applied onto the rectangular copper wire and baked to obtain a rectangular enameled wire. The coating on the flat surface of the obtained rectangular enameled wire was extremely uneven. Comparative Example 2 The unevenness of the enamel film on the flat surface of the rectangular enameled wire obtained in Comparative Example 1 was corrected rolled to a rolling reduction of 0.3% to obtain a rectified rectangular enameled wire. Comparative Example 3 The rectangular enameled wire obtained in Comparative Example 1 was corrected and rolled so that the unevenness of the enamel film on the flat surface was 17% to obtain a rectangular enameled wire. Example 1 The unevenness of the enamel film on the flat surface of the rectangular enameled wire obtained in Comparative Example 1 was corrected rolled to a rolling reduction of 0.7% to obtain a rectified rectangular enameled wire. Example 2 The unevenness of the enamel film on the flat surface of the rectangular enameled wire obtained in Comparative Example 1 was corrected rolled to a rolling reduction of 5% to obtain a rectified rolled rectangular enameled wire. Example 3 The unevenness of the enamel film on the flat surface of the rectangular enameled wire obtained in Comparative Example 1 was corrected rolled to a rolling reduction of 15% to obtain a rectified rectangular enameled wire. The following table shows the characteristics test results of the rectangular enamelled wires obtained in the comparative examples and examples.

[Table] The test method for the characteristic test is as follows. The elongation property test is a test that evaluates the elongation properties of the coating on rectangular enameled wire. This test is first of a length of approx.
A 30cm rectangular enamelled wire was taken, and the gauge length was 20cm.
Attach it to a tensile testing machine so that the tensile speed is 200.
The crack initiation elongation rate (%) of the enamel film was determined when it was stretched at mm/min. The coil space factor is the ratio (%) of the coil cross-sectional area to the sum of the cross-sectional areas of the wound rectangular enamelled wire. This test uses a model coil (length x width x length, 70
(mm x 70mm x 140mm). As is clear from the results, the rectangular enamelled wire manufactured according to the present invention can improve the unevenness of the coating on the flat surface without significantly impairing the elongation properties of the rectangular enameled wire coating compared to the rectangular enameled wire manufactured by the conventional method. In addition, it is possible to significantly improve the coil space factor when winding an electrical equipment coil, and its industrial value is great.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a rectangular enamelled wire manufactured by a conventional method, FIG. 2 is a cross-sectional view of a rectangular enameled wire manufactured by the method of the present invention, and FIG. 3 shows an embodiment of the manufacturing method of the present invention. FIG. 1: conductor, 2: film, 3: delivery bobbin,
4: Guide pulley, 5: Rolling roll, 6: Annealing furnace, 7: Paint tank, 8: Paint drawing die, 9:
Baking furnace, 10: Straightening roll, 11: Winding bobbin.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a rectangular enameled wire in which a round conductor is rolled into a rectangular conductor, and then an enamel paint is applied and baked on the rectangular conductor to obtain a rectangular enameled wire. When the maximum finished dimension in the direction is a, the finished dimension in the flat direction after straightening rolling is b, and the rolling reduction ratio is a-b/a x 100, rolling the rectangular enameled wire at a rolling reduction range of 0.5 to 15%. A method for producing a rectangular enameled wire, which comprises correcting the unevenness of an enamel film.