JPS5928006B2 - Baking molding method for insulated conductors - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of baking and forming insulated conductors for electrical equipment.

Conventionally, as a baking molding method for insulated conductors, an insulating layer containing an uncured or semi-cured thermosetting resin is applied around the conductor to wrap it, and baking is performed while applying pressure from the outside toward the center. Molding methods are known.

In this case, the pressurizing means is a cloth-like, tape-like, or sleep-like heat-shrinkable material that is wrapped or covered around the outer periphery of the insulated conductor, and is pressurized by the tightening force that contracts when heated at high temperatures. There is. However, the heat shrinkable bodies used in this case are generally vertical,
Since the lateral thermal contraction rates are approximately the same, there is a drawback that the entire surface of the insulated conductor cannot be tightened with uniform centripetal pressure.
The situation will be explained in detail with reference to FIGS. 1 and 2. To carry out baking forming, an insulated conductor 1 is provided with an insulating layer 2 around it, and the insulated conductor is surrounded by a thermal buffer 3 to uniformly transfer heat, and a planar electric heating element T for heating the insulated conductor 1 is surrounded by a thermal buffer 3. Apply it to the outside,
Further, the heat transfer body 4 is applied to the outside of these, and the heat shrink body 5 is wound from the outside while sequentially shifting the position.

Thereafter, the planar electric heating element T is energized to heat and form it.
At this time, the heat-shrinkable body 5 is heated and contracts, and the contraction in the longitudinal direction of the heat-shrinkable body becomes an effective force for tightening the insulated conductor, but it also contracts in the width direction, so the tightening area by the heat-shrinkable body is Because of this, it is not possible to obtain a uniform tightening force over the entire surface, and gaps 6 are created between the heat-shrinkable bodies, creating areas where no tightening force can be applied at all, so the heat-shrinkable bodies are wound in multiple layers. The need arose. That is, as shown in FIG. 2, when a conventionally used heat-shrinkable body is heated uniformly with both ends held by fixtures 8, the heat-shrinkable body 5 generally forms a broken line at the center where it is not held. As shown in , it has the disadvantage that the shrinkage in the width direction becomes large. on the other hand,
A method is also known in which a sleeve that contracts only in the radial direction but not in the longitudinal direction is inserted through the insulated conductor and then heated and contracted.

However, this method only requires that the insulated conductor surface is completely smooth and its cross-sectional shape is the same in the axial direction (longitudinal direction), but in general, the insulated conductor surface has various unevenness and (direction) There are also cases where the cross-sectional size of the vc insulated conductor is different. The heat shrink sleeve before shrinking has a uniform shape,
After shrinkage, the shrinkage force changes between the recesses and protrusions or between the small cross section and the large cross section of the insulated conductor, and when viewed in the axial direction, the shrinkage force lacks uniformity. SUMMARY OF THE INVENTION An object of the present invention is to provide a baking molding method that eliminates the drawbacks of the prior art described above and can apply uniform centripetal pressure from the periphery of an insulated conductor to form a homogeneous molded insulating layer.

That is, the present invention achieves the intended purpose by forming a heat-shrinkable body by overlapping and staggered winding of tapes that are woven with non-heat-shrinkable fibers as weft threads and heat-shrinkable fibers as warp threads. It was designed to do so.

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

An insulating layer 2 containing an uncured or semi-cured thermosetting resin is wrapped around the conductor 1, and a thermal buffer 3 is placed on the outside of the insulating layer 2.
A planar electric heating element r was placed on the outside of the electric heating element r, and a heat shrinkable body 5 made of polyester fiber was wrapped around the outside of the electric heating element r via a thermal conductor 4 having relatively poor thermal conductivity. As the heat-shrinkable body 5 in this case, as illustrated in FIG. 3, fibers 9 having heat-shrinkability in the longitudinal direction, that is, the warp, are used.
Fibers with almost no heat shrinkage in the width direction, that is, in the weft.
0 was used, and these were woven together into a tape shape. Thereafter, the insulating layer 2 is hardened and molded with a uniform tightening force applied to the entire surface of the insulated conductor by applying current to the sheet electric heating element Rvc and heating it, thereby achieving stable characteristics. We were able to obtain an insulated conductor. As described above in the present invention, a heat-shrinkable body is formed by weaving non-heat-shrinkable fibers as weft threads and heat-shrinkable fibers as warp threads, and then wrapping the tape in a staggered manner. Therefore, even if the surface of the insulated conductor is not smooth, uniform centripetal pressure can be applied from around the insulated conductor to perform homogeneous baking molding.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an insulated conductor to explain the conventional baking molding method, Fig. 2 is a plan view of the heat-shrinkable body showing the properties of the heat-shrinkable body used in the conventional method, and Fig. 3 is the present invention. FIG. 4 is a plan view illustrating a heat shrinkable body used in the present invention, and FIG. 4 is a perspective view of an insulated conductor for explaining an embodiment of the present invention. 1... Conductor, 2... Insulating layer, 5...
...Heat shrinkable body.

Claims (1)

[Claims] 1. A method of baking-molding an insulated conductor in which an insulating layer containing a thermosetting resin is applied around the conductor by pressurizing it from the outside by the contraction force of a heat-shrinkable body provided outside the insulating layer. However, this is a baking molding method for insulated conductors that are formed by overlapping and staggered winding of tapes made by interweaving non-heat-shrinkable fibers as weft threads and heat-shrinkable fibers as warp threads.