JPS603728B2 - Insulated conductor molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an insulated conductor molding device for hardening an insulating layer containing a thermosetting resin such as a vertical mill wire ring of an electrical device or an insulating steel strip connected thereto by heating and pressing. .

Recent electrical equipment has increased in capacity, or has become 4-shaped with the same output, and the insulation of conductors, such as the insulated wire ring used for this or the insulated steel strip connected to the wire, has a thin insulation layer and has insulation characteristics. Increasingly, there is a demand for a material with good insulation properties and uniform insulation properties with little variation.

There are two methods of insulating conductors: the vacuum pressure impregnation method and the resin-rich method, both of which involve impregnating an inorganic material such as mica or glass with a thermosetting synthetic resin such as epoxy resin or polyester resin and applying heat and pressure. By hardening,
A common structure for insulation these days is to integrate the insulation layers.

However, in both the vacuum pressure impregnation method and the gin-rich insulation method, the insulation properties vary greatly depending on the structure of the molding device used for curing under heat and pressure. FIG. 1 shows a general molding paint of a secondary molding device and a cross-sectional view of a state in which an insulated conductor is molded using the molding paint.

The conductor 1 is wrapped with an insulating layer 2, and further has an insulating layer 2 on its outer surface.
It is surrounded by a mold 3 having an L-shaped cross section. During molding, the molding jig 3 is pressurized from the outside by liquid pressure, the pressure of a shrink tape, or mechanical pressure from a spring, etc., and at the same time heated by a heating device. The thermosetting synthetic resin cures and forms a solid insulating layer. The conductor 4 is usually made by bundling multiple wires or forming a wire ring with multiple turns, but since the cross section is generally quadrilateral, two L-shaped molding jigs are used to make the conductor 4. The sides are pressed. The function of the mold jig 3 during this pressurization is that a force Fa is applied to the upper and lower insulating layers 2a in a direction perpendicular thereto, and to the both side insulating layers 2b,
A force Fb in a direction perpendicular to this is applied. At this time, the insulating layer 2
If the coefficient of friction between the mold jig 3 and the mold jig 3 is set as
A force Fd=Fb×mu in the same direction as this is applied to the surface of the insulating layer 2b on both sides, and the side facing the curved corner of the L-shape of the mold jig 3 is the closed corner, and the end of the side of the L-shape is If the side is called the open side corner, the open side corner lc of the conductor
The insulating layer 2 at the closed corner is
A tensile force is applied to the surface c, and the insulating layer 2c at the closed corner becomes thinner. Also, the force F on the conductor corner ld side is
c and force Fd, a compressive force is applied to the surface of the insulating layer 2d at the open corner, and the insulating layer 2d at the open corner becomes thicker. In recent years, with the increase in the capacity of electrical equipment and the increase in voltage, the thickness of the insulating layer 2 has also become thicker than before, and the thicker the insulating layer 2 is, the more
The non-uniformity of the thickness of 2d becomes significant.

The insulation thickness has a direct effect on the dielectric breakdown voltage, and in particular, if the insulating layer 2c at the corners becomes extremely thin, this causes an extremely low dielectric breakdown voltage. Therefore, conventionally, the thickness of the insulating layer 2 had to be designed to be thicker overall in consideration of the thinning of the insulating layer 2c at the corners, making it difficult to increase the voltage and downsize, and increasing manufacturing costs. It had drawbacks. In the present invention, the insulation thickness of the insulation layer of a conductor is not locally thinned in any part, but rather it is made somewhat thicker at the corners. An object of the present invention is to provide an insulated conductor molding device that can manufacture an insulated conductor with good insulation properties and low crackling and excellent reliability even when the conductor is thick.

Hereinafter, one embodiment of the present invention shown in FIG. 2 will be described. In FIG. 2, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted. A flat first molding jig 4 is brought into contact with each of the four sides of the insulating layer 2 of the conductor 1, which has a quadrilateral cross section.
A letter-shaped second mold pick-up tool 5 is brought into contact. The pressurizing device is one that mechanically pressurizes using a clamp 6 and a spring 7, which is installed at alternate angles in the longitudinal direction of the conductor 1. In addition, heat shrinkable material, atmospheric pressure, hydraulic pressure, or It may also be done by powder pressing or the like. Then, an adhesive tape (not shown) is provided on the surface of the first mold pick-up tool 4 that comes into contact with the insulating layer 2 to increase the coefficient of friction between the insulating layer 2 and the first mold pick-up tool 4. Teflon (not shown) is applied to the contact surface of the mold holder 5 with the first mold jig 4 to reduce the coefficient of friction between the first and second mold jig 4 and 5, and to reduce the pressure. In this case, the second molding jig 5 is made to slide against the first molding jig. In addition, as a means to reduce the coefficient of friction between the first and second mold pick-up tools 4 and 5, Teflon coating may be applied to the first mold odor pick-up 4 side, and It may be applied to both mold jigs. Also, means for applying or supporting a lubricant such as silicone grease, or means for spraying Teflon on at least one of the contact surfaces between the first and second mold linings 4 and 5. Alternatively, there is a method of attaching or winding a Teflon sheet. As another means of increasing the coefficient of friction between the insulating layer 2 and the first mold odor pick-up 4, adhesive, high viscosity varnish, etc. may be applied to the contact surfaces of the first mold pick-up tool 4. means for adhering the to the insulating layer 2, the first
There is a method of mechanically or chemically roughening the contact surface of the mold jig 4 to the insulating layer 2. Next, the effect will be explained.

When applying pressure, a force Fa is applied to the upper and lower insulating layers 2a in a direction perpendicular to this, and a force Fb in a direction perpendicular to this is applied to the insulating layers 2b on both sides, and the insulating layer 2 is applied with these forces. The principle of being pressurized is the same as that of conventional pressurization. Now, considering the forces Fc and Fd shown in FIG. 1 that are conventionally applied to the surfaces of the upper and lower insulating layers 2a and both side insulating layers 2b, in the one shown in FIG. 2 of this embodiment, each mold When the jigs 4 and 5 are pressurized by an external force, the second mold pick-up 5 slides relative to the first mold jig 4, so the forces Fc and Fd are not generated. Then, only the forces Fe and Ff, which are the reaction forces pushed by the first mold paint 4, are applied to the insulating layers 2c and 2d at each corner, and the insulating layers 2c at the closed corners of the subordinate columns shown in FIG. without reducing the insulation thickness. On the contrary, the insulating layers 2c and 2d at each corner are all uniformly coated with the upper and lower insulating layers 2a,
It can be formed thicker than 2b. It goes without saying that the upper and lower insulating layers 2a and 2b on both sides have a uniform thickness. It is extremely easy in terms of industrial production to attach adhesive tape to the first mold pick-up tool 4 and to attach Teflon to the second mold odor control 5. As mentioned earlier, the conductor 11 has a quadrilateral cross section, so the electric field in the insulating layers 2c and 2d at each corner is higher than the electric field in the insulating layers 2a and 2b at the top and bottom and on both sides. , an insulating layer 2 at each corner of the insulated conductor manufactured by the apparatus of this example.
As mentioned above, the thicknesses of c and 2d are thicker than the upper, lower, and both side insulating layers, so that the insulating strength at the weakest point can be increased and the insulating properties can be improved.

FIG. 3 shows the insulation characteristics of insulated conductors manufactured using the conventional molding device and the molding device of this embodiment. The vertical axis shows the dielectric breakdown voltage, and the mechanical axis shows the number of turns of the insulating tape on the insulating layer. It can be seen from this that the curve b representing the present embodiment is far superior to the curve a representing the conventional one. FIG. 4 shows another embodiment, which is the same as FIG. 2 except that the pressurizing device is replaced with a heat-shrinkable material 8.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but may include the following without changing the gist thereof:
Of course, it can be implemented with various modifications.

As explained above, according to the present invention, the outer four parts of the insulating layer
A flat first mold pick-up tool is brought into contact with each of the surfaces, and a second mold pick-up tool with an L-shaped cross section is put in contact with each of the outer corners of the first mold pick-up tool.
By making it slide against the mold jig,
The insulating layer at each corner of the manufactured insulated conductor is uniformly thicker than the upper, lower, and both side insulating layers, and the thickness of the upper, lower, and both side insulating layers is also uniform. This can be similarly achieved with an insulating layer or a thin insulating layer for low-voltage equipment, and it is possible to manufacture a highly reliable insulated conductor that always has high insulating properties and has little variation in properties.

Therefore, it is possible to design and manufacture a thin insulating layer without increasing the thickness of the insulating layer unnecessarily, thereby increasing the cooling effect and making it possible to reduce the size and weight of the device.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the main parts of a conventional insulated conductor molding device, FIG. 2 is a sectional view showing an embodiment of the insulated conductor molding device of the present invention, and FIG. 3 is a sectional view of the conventional insulated conductor molding device and the present invention. FIG. 4 is a curve diagram showing a comparison of insulation properties of insulated conductors manufactured in one embodiment, and FIG. 4 is a sectional view showing another embodiment. 1... Conductor, 2... Insulating layer, 4... First mold jig, 5... Second mold vulgarity, 6, 7... - Clamp and spring that are pressurizing devices, 8...Heat shrink material that is pressurizing devices. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In an insulated conductor molding device for curing an insulating layer wrapped around a conductor having a quadrilateral cross section and containing a thermosetting resin under heat and pressure, a flat plate is provided on each of the four outer sides of the insulating layer. A first molding jig is brought into contact with the first molding jig, a second molding jig having an L-shaped cross section is brought into contact with each outer corner of the first molding jig, a pressure device is provided on the outside of the second molding jig, and the insulating layer is The coefficient of friction between the first mold jig and the second mold jig is set to be larger than the coefficient of friction between the first and second mold jig, so that the second mold jig is moved against the first mold jig during pressurization. An insulated conductor molding device characterized by being made to slide. 2. The means for reducing the coefficient of friction between the first and second molding jigs is an insulation according to claim 1, characterized in that Teflon is baked on the contact surface of at least one of the molding jigs. Conductor molding equipment. 3. The means for increasing the coefficient of friction between the insulating layer and the first molding jig is characterized in that an adhesive tape is provided on the contacting surface of the insulating layer of the first molding jig. The insulated conductor molding device according to item 1 or 2.