JPS6243532B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a coreless coil formed by winding a self-welding wire.

A coreless coil is produced by winding self-fusing electric wires, temporarily fixing the self-fusing electric wires to each other and each single coil to form a coil group, shaping this coil group into a predetermined shape such as a cup shape or a flat shape. Manufactured completely solid.

Conventionally, when temporarily fixed coil groups are shaped into a predetermined shape using a predetermined mold, the insulation coating is seriously damaged due to the friction between the self-fused wires that form the coil group, resulting in layer shorts and wire breaks in the coil group. There were many defects. Therefore, when temporarily fixing single coils to form a coil group, temporary fixing is performed using a re-softened synthetic resin coating provided on the single coil in advance, and the coil group is shaped into a predetermined shape while this synthetic resin coating is melted. By shaping and then polymerizing and curing the synthetic resin coating, a completely fixed iron-free coil was obtained.

However, with this method, the amount of synthetic resin that can be attached to the coil group in advance is limited.
Because the self-fusing wires forming the coil are not in close contact with each other and the ends of the coil are not fully integrated, it is generally difficult to heat cure thermosetting resins such as molding materials. Therefore, it was a completely integrated coreless coil. In other words, with conventional ironless coils, there is a limit to the amount of synthetic resin coating used to temporarily secure the coil group.
It was not possible to leave the coreless coil in use after it had been shaped into a specific shape, so it was necessary to completely integrate it by heat curing thermosetting resin such as molding material. .

The present invention is based on the conventional manufacturing method of a coreless coil, and is aimed at further streamlining the method and at the same time, reducing weight, which is one of the important characteristics of a coreless coil.

The present invention provides a method for manufacturing a coreless coil in which a coil wound with self-fused electric wire is temporarily fixed, and then shaped and fixed into a predetermined shape. The temporary fixing is performed by providing a synthetic resin coating film as a component, the shaping is performed while heating and melting the synthetic resin coating film using a predetermined mold, and the synthetic resin coating film is expanded, and then the synthetic resin coating film is expanded. This method is characterized by completely fixing the coil by polymerizing and curing the coating film.

In the present invention, a synthetic resin coating film containing a foaming agent or microcapsules containing it as an essential component refers to a basic resin, a compound capable of polymerizing and curing it, a polymerization initiator, an organic solvent used as necessary, etc. refers to something that consists of Examples of blowing agents that are essential components of this synthetic resin coating include dinitrosopentamethylenetetramine,
Substances that generate gas when heated, such as azodicarbonamide, toluenesulfonyl hydrazide, and azoisobutylnitrile, or substances that generate gas when heated in microcapsules such as polystyrene and polyα-methylstyrene, and even butane,
It is impregnated with an aliphatic or cycloaliphatic hydrocarbon as a blowing agent that does not dissolve fine capsule materials, such as isobutane, propane, pentane, hexane, heptane, petroleum ether, dichloropentane, and cyclopentadiene.

The basic resin includes unsaturated polyester, diallyl phthalate, urethane, epoxy, etc., and among these, unsaturated polyester, diallyl phthalate, etc. are preferred. The unsaturated polyester mentioned here refers to α- and β-unsaturated carboxylic acids or these together with saturated dicarboxylic acids, organic acids including saturated and unsaturated monocarboxylic acids, glycols, polyhydric alcohols, and monohydric alcohols. It is a product obtained by dissolving an unsaturated polyester obtained by an esterification reaction with alcohols such as alcohols in a crosslinking monomer that can be polymerized with the unsaturated polyester, and usually contains a small amount of a polymerization inhibitor, and if desired, a small amount of polymerization inhibitor. It contains polystyrene, polyethylene, polymethyl methacrylate and its copolymer, polyvinyl acetate, polycaprolactone saturated polyester, etc. as a shrinking agent. Moreover, diallyl phthalate refers to polymers such as diallyl orthophthalate and diallyl isophthalate, copolymers thereof, and crosslinking monomers that can be polymerized therewith.

The polymerization initiator for the basic resin is an organic peroxide such as benzoyl peroxide or methyl ethyl ketone peroxide, and the accelerator is a metal salt such as cobalt naphthenate or cobalt octoate, or an amine such as triethanolamine or diethylaniline. It is a kind.

As a method for forming a synthetic resin coating film containing the above-described foaming agent or microcapsules containing the foaming agent as an essential component on the surface of a coil obtained by winding a self-fused electric wire, the coil is coated with an organic solvent of the synthetic resin. After immersing in a solution, drying to the touch, dropping, spraying, or the like may be used as appropriate.
The organic solvent used in this case is preferably a ketone, an alcohol, or the like, and is preferably one that is soluble in the basic resin and capable of solvent-bonding the self-fusing electric wire used. In addition, when using the dipping method, if the viscosity of the synthetic resin solution containing the blowing agent or the microcapsules containing it is set to 20 to 100 cps, it becomes easy to form the synthetic resin coating film on the coil surface. Further, it is desirable to adjust the coating film thickness to 50 to 100μ.

Experimental examples of the present invention will be described below and compared with comparative examples.

[Experiment example]

A self-fusing electric wire having a butyral resin fusing layer having a wire diameter of 0.15φ was wound 49 times, and seven of these wires were stacked and arranged on a winding frame. An acetone solution of a synthetic resin containing microcapsules consisting of the following components was dropped onto this coil and volatilized to obtain a coil group temporarily fixed by the synthetic resin coating film. However, 90 parts by weight of fine capsules diallyl phthalate, 10 parts by weight of monomer, 1 part by weight of benzoyl peroxide, and 3 parts by weight of fine capsules were vinylidene chloride-acrylonitrile copolymer with isobutane as an encapsulating agent.

The apparent thickness of the synthetic resin coating film provided on the coil surface by temporary fixation was 80 to 100 μm. The softening temperature of this coating is 80 to 90°C, which is approximately the same as the expansion temperature of the microcapsules dispersed in the coating.

The coil group has an inner diameter of 19.5φ, an outer diameter of 20.8φ, and a height of 30.0mm.
The coils were transferred to a cup-shaped coil shaping mold, and the coil group was shaped by clamping the mold at 130°C. After shaping, the mold was clamped for 3 minutes to polymerize and harden the synthetic resin coating, and then the molding was started.The space in the mold other than the coil part was also filled by the expansion of the synthetic resin, making it completely solid. A coreless coil in good condition was obtained.

The hardened state of the synthetic resin in the parts corresponding to the mold wall surface and the coil surface in the thus obtained iron-free coil is such that the microcapsules do not expand and are solidly polymerized and hardened. The iron coreless coil was not in use.

[Comparative example]

A coreless coil was manufactured under the same conditions as in the above experimental example except that it did not contain microcapsules. At this point, the coreless coils had imperfect adhesion in parts where the coils were not in close contact with each other and at the ends of the coils, so they were further integrated by transfer molding of diallyl phthalate resin molding material.

As is clear from the above-mentioned experimental examples and comparative examples, according to the present invention, the coil group is shaped into a predetermined shape,
Since the coreless coil after polymerizing and curing the synthetic resin coating can be used as is, the manufacturing process can be streamlined, and one of its important properties is weight reduction.

Claims (1)

[Claims] 1. A method for producing a coreless coil in which a coil wrapped with self-fused electric wire is temporarily fixed and then shaped and fixed into a predetermined shape, in which a foaming agent or a microcapsule containing the foaming agent is an essential ingredient in the wound coil. The temporary fixation is performed by providing a synthetic resin coating, the shaping is performed while heating and melting the synthetic resin coating using a predetermined mold, and the synthetic resin coating is expanded, and the synthetic resin coating is further expanded. A method for manufacturing a coreless coil, which is characterized by completely fixing the coil by polymerization and hardening.