JPS58192314A - Manufacture of resin molded electromagnetic winding - Google Patents

Abstract

PURPOSE:To prevent the decrease of insulation and the deformation of a coil by a method wherein the temperature of a coil which is loaded is kept than the kick-off temperature of resin composition at the time of filling unsaturated polyester resin composition into a metal mold. CONSTITUTION:The metal mold is pre-heated, the temperature of the insulation wire which forms the coil is kept less than the kick-off temperature of the unsaturated polyester resin, and the resin is filled into the cavity of the metal mold. At the temperature less than kick-off one, there is not simultaneous generation of many radicals based on the initiation of rapid decomposition of the polymerization initiator in the unsaturated polyester resin, and therefore the reaction of polymerization is not rapidly started. Thereby, the resin reaches over between wires securely, and accordingly the decrease of insulation property and the deformation of a coil due to sealing can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a resin-molded electromagnetic winding in which at least a part of the electromagnetic winding is transferred or injection molded with an unsaturated polyester resin composition. The method is characterized in that the temperature of the electromagnetic winding to be molded is kept below the kick-off temperature of the resin composition during the process, and the purpose is to improve the reliability of the resin-molded electromagnetic winding.

Generally, an electromagnetic winding formed by winding electric wire is integrated with its supporting core using a binder such as a face. In addition, we are improving the characteristics and reliability of electromagnetic windings, making them smaller and lighter,
For the purpose of streamlining the manufacturing process, etc., resin-molded electromagnetic windings, which are made integrally rigid by heat curing of thermosetting resin, are made into a rigid body by heating and curing thermosetting resin so as to include the electromagnetic windings or their supporting cores as appropriate. The combination is considered as a stator for F-class motor, using polyurethane, polyester wire, etc. as the electric wire forming the electromagnetic winding, and an unsaturated polyester resin composition with a molding temperature of 130 to 160 ° C as a thermosetting resin composition. Some systems using this technology have been put into practical use. Note that the polyurethane and polyester wires referred to here are insulated wires in which an insulating paint containing polyurethane or polyester as an active ingredient is directly coated and baked on the conductor forming the electromagnetic winding, or butyral, etc.
A self-bonding insulated wire with a fusion coating containing phenoxy or the like as an active ingredient. The reason why the above-mentioned polyurethane or polyester wire is used is that the normal temperature of these resin-molded electromagnetic windings does not exceed approximately 120"C, and the electromagnetic winding structure allows it to be directly wound around the support core. In this case, polyurethane wire, which has excellent workability in winding process, is easily used, and when it is necessary to insert electromagnetic winding wire into the support core, polyester wire, which has excellent wear resistance, is used.

On the other hand, an unsaturated polyester resin composition is made by adding a polymerization initiator to an unsaturated polyester resin made by dissolving an unsaturated polyester alkyd with a copolymerizable monomer such as styrene.
Furthermore, reinforcing agents such as glass fibers and granular fillers such as calcium carbonate are added as essential ingredients to the total amount of the resin composition.
It refers to Priminx or BMC which is kneaded together with various additives such as a low shrinkage agent, a pigment, a mold release agent, a flame retardant, a double polymerization inhibitor, etc., which are added as needed by weight or more.

The reason why the above-mentioned unsaturated polyester resin composition is used is that it generally cures by polymerization extremely quickly compared to ezoxy resin, diallyl phthalate resin, etc., and can obtain sufficient heat of polymerization. This is because the molding shrinkage rate can be extremely easily reduced by adding the resin. In other words, fast curing is effective for increasing the productivity of resin-molded electromagnetic windings, and low shrinkage can easily improve the thermal shock resistance of resin-molded electromagnetic windings. This is because the melting point of the thermoplastic resin is relatively high even in the presence of the thermoplastic resin for oxidation, so sufficient heat resistance can be ensured at a common temperature of 120"C or less.Such unsaturated polyester resin composition Reinforcing agents such as glass fiber and granular fillers such as calcium carbonate are used as essential components of
It is an essential active ingredient from the viewpoint of the characteristics and reliability of the resin-molded electromagnetic winding, which plays an important role in the shrinkage rate, thermal conductivity, thermal expansion coefficient 2, mechanical properties, etc. of the resulting molded and cured product. However, on the other hand, such fibers and reinforcing agents are known as thickeners for unsaturated polyester resins and significantly reduce the fluidity of the resin composition. As a result, in the manufacturing process where electromagnetic windings made of insulated wires containing polyurethane or polyester as an active ingredient are integrally made into a rigid body by injection or transfer molding, unsaturated polyester is added between the windings and in narrow gaps with the support core. When the resin composition is filled, it may cause insufficient filling, or it may cause damage to the wire coating due to deformation of the electromagnetic winding, which may reduce the reliability of the resin-molded electromagnetic winding, such as deterioration of the insulation performance of the electromagnetic winding. It was also the cause of the decline.

In this way, the polymerization curing characteristics and fluidity of the unsaturated polyester resin composition are adjusted depending on the manufacturing conditions, manufacturing method, and manufacturing procedure when molding each part of the electromagnetic winding to produce a resin-molded electromagnetic winding. Processability of unsaturated polyester resin composition 9 Workability 2. This has a significant impact on productivity and the characteristics and reliability of resin-molded electromagnetic windings, and many efforts have been made to adjust additives, mold structures, and electromagnetic winding structures. Ta.

The present invention has been made in view of the above background, and includes a method for manufacturing a resin-molded electromagnetic winding in which at least a part of the electromagnetic winding is transferred or injection molded using an unsaturated polyester resin composition. The present invention is characterized in that at least the temperature of the electromagnetic coil loaded in the mold cavity is maintained below the kick-off temperature of the resin composition when filling the mold cavity with the composition. However, in the present invention, the kick-off temperature of an unsaturated polyester resin refers to the temperature at which the polymerization initiator in the resin composition rapidly begins to decompose, generating many radicals at once and rapidly starting the polymerization reaction. To tell. Note that the unsaturated polyester resin composition in the present invention is not particularly limited. Specifically, no special changes are required in the molecular weight of the unsaturated hexapolyester alkyd, its constituent components, the copolymerizable monomer concentration, fibers, fillers, or other various additives added as necessary. On the other hand, the electric wire and winding structure constituting the electromagnetic winding are not limited either.

As a specific implementation means of the present invention, it is effective to adjust the heat conduction from the mold wall surface to the electromagnetic winding in the electromagnetic winding structure in combination with the support core. Alternatively, it can be easily implemented by adjusting the mold structure, manufacturing conditions, etc.

The present invention will be explained in detail below.

(Example 1) Two unsaturated polyester resin compositions A and B were prepared.

However, A is isophthalic acid strongly unsaturated polyester alkyd,
An unsaturated polyester resin consisting of styrene and a low shrinkage agent, and an unsaturated polyester resin consisting of terephthalic acid main unsaturated polyester alkyd and styrene were used for B, and a conventional method was used to obtain the composition shown in Table 1 (unit: weight %). It has been adjusted.

Table 1 FIG. 1 is a characteristic diagram showing the relationship between the viscosity and temperature of the above-mentioned failures A and B. The activation energies of the apparent flow of A and B are both 10 Kc m0f2, which is the same, but on the high temperature side, linearity is lost with respect to the reciprocal of the absolute temperature. The rise of the exothermic peak due to polymerization measured by a differential scanning calorimeter in A and B coincides with the temperature at which linearity is lost on the high temperature side, as in A and B in FIG. This temperature is 113"C for A and 121°C for B, and in both cases, the polymerization initiator in each unsaturated polyester resin composition begins to decompose rapidly, generating many radicals at once and inhibiting the polymerization reaction. This is the temperature at which the temperature starts rapidly, that is, the kink-off temperature (hereinafter referred to as reference temperature) of the unsaturated polyester resin composition in the present invention.

Next 1. Twisted pairs were made using insulated wires made of polyurethane or polyester, which are the active ingredients of an insulating film that is applied directly onto the conductor. A transfer molding mold was prepared that had a structure that supported only both ends of this twisted pair and used a heat insulating material for the support portions.

FIG. 2 is a schematic sectional view of the mold.

In the figure, 1 is the twisted pair, 2 and 2' are silicone rubber parts that support and insulate the twisted pair 1, and 3 is the part that supports and insulates the twisted pair.
A heat exchange part provided in the heat insulating part 2, 4 is a lower mold, 5 is an upper mold, and 6 is a gate part provided in the upper mold 5.

This mold has a structure that allows electricity to be applied to the twisted pair when the twisted pair is loaded and the mold is closed, and the temperature of the twisted pair can be adjusted separately from the mold temperature using the heat exchange part provided in the twisted pair support part 2. It is something.

A transfer mold with the above functions was heated to 150°C.
After heating to eg, the twisted pair prepared in advance is loaded, and the temperature of the insulated wire is adjusted to the kick-off temperature of the unsaturated polyester resin compositions A and B used, 5°C2±10°C1.
The unsaturated polyester resin was pumped into the mold cavity while being controlled at ±20″C.

FIG. 3 is a characteristic diagram showing the relationship between the dielectric breakdown voltage of the resin-molded twisted pair measured and the rate of decrease from the original dielectric breakdown voltage when the kick-off temperature is used as the reference temperature. As is clear from this figure, polyester wire...0
・B (polyester insulated wire is also molded with unsaturated polyester resin composition B), polyurethane wire...
・B (polyurethane insulated wire molded with unsaturated polyester resin composition B), polyester wire...0...A
(molded polyester insulated wire with unsaturated polyester resin composition A), polyurethane wire - A (
It can be seen that all of the polyurethane insulated wires (molded with unsaturated polyester resin composition B) have a high dielectric breakdown voltage retention rate and are stable below the reference temperature. Therefore, the resin is reliably spread between the wires of the electromagnetic winding.

In this way, the present invention, when molding at least a part of the electromagnetic winding with an unsaturated polyester resin composition, adjusts the temperature of the electromagnetic winding loaded into the mold cavity in advance during the filling process of the unsaturated polyester resin composition to the above-described temperature. Adjusted to below the kick-off temperature of the resin or composition, ensuring that the resin spreads between the windings and reducing the insulation performance of the windings due to molding.

Deformation etc. can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a characteristic diagram showing the relationship between apparent viscosity and temperature of unsaturated polyester resin compositions A and B, and the temperatures of A and B in the figure are kick-off temperatures (reference temperatures). Fig. 2 is a schematic cross-sectional view of a mold that can adjust the temperature of the insulated wire, and Fig. 3 is a schematic cross-sectional view of a mold that can adjust the temperature of the insulated wire. FIG. 2 is a characteristic diagram showing the relationship between the dielectric breakdown voltage retention rate of the obtained resin molded insulated wire and the corresponding reference temperature ±t″C. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2, Figure 3, 11.

Claims (1)

[Claims] At least a part of the electromagnetic winding is molded with an unsaturated polyester resin composition, and during the filling process of the unsaturated polyester resin composition, the temperature of the electromagnetic winding loaded in advance into the mold cavity is set to the kick-off temperature of the resin composition. The manufacturing method of resin molded electromagnetic winding is as follows.