JPH07112337B2 - Ironless armature manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coreless motor widely used in OF, FA and electrical equipment fields such as copying machines, NC machine tools, car coolers, and more specifically, insulated wires or self-bonding. TECHNICAL FIELD The present invention relates to a method for manufacturing a wire-wound ironless core armature in which an armature winding is formed from a magnetically insulated wire and the winding is sealed with an unsaturated polyester resin composition.

Structure of Conventional Example and Problems Thereof In general, an armature winding is formed by winding an insulated wire or a self-bonding insulated wire and integrally forming it with a supporting iron core by a binder such as varnish. However, in the case of an armature winding that does not have a supporting iron core like a non-iron core armature, the armature winding itself must be integrally rigidified by some method. In particular, in the case of a coreless armature having a relatively large capacity of several watts to several kilowatts, the characteristics required for integrally rigidizing the armature winding are also high. Above all, dimensional stability, heat resistance, mechanical properties, electrical properties, etc. are important for ensuring the reliability of the iron-free core armature, and unsaturated polyester or epoxy resin is filled within the range satisfying these properties. An ironless core armature in which an armature winding is sealed with a resin composition obtained by collectively kneading an additive, a release agent, a pigment, and other additives that are added as necessary has been put into practical use.

The reason why unsaturated polyester resin or epoxy resin is used as the resin composition for sealing the armature winding is that the melting viscosity at the time of sealing the armature winding is low, so that a dense electric machine is used. This is because it is easy to seal the child winding and the deformation of the armature winding is small, which is advantageous in maintaining the motor characteristics. Moreover, since it is possible to mix a relatively large amount of inorganic filler, the conductor of the armature winding,
Because the difference in thermal expansion with the resin composition that seals this is reduced, or because the thermal conductivity of the resin composition becomes relatively large,
This is because, for example, it is advantageous in suppressing a temperature rise during motor operation and dimensional stability. The unsaturated polyester resin is used for a motor having a comparatively light load, and the epoxy resin is used for a comparatively heavy load. The reason for this is that, in general, unsaturated polyester resin has an inorganic filler content of about 60 to 70% by weight from the viewpoint of workability at the time of encapsulating the armature winding, and, for example, as much as 80% by weight like epoxy resin It is difficult to mix the above inorganic filler.
In addition, unsaturated polyester resin is significantly faster than the curing of epoxy resin, so that it has a large curing strain and it is difficult to secure dimensional accuracy.For example, a low shrinkage agent made of a thermoplastic resin is required. This is because it is disadvantageous compared to when it is used.

However, as described above, the iron-free core armature having practically sufficient reliability is widely used in various industrial fields due to the operating characteristics and structural characteristics of the motor derived from the armature structure. As a result, the range of uses where the load is relatively light has expanded. Particularly in this type of field, there are increasing demands for economical advantages of ironless motors, rationalization of manufacturing methods, and stabilization of quality.

From the above viewpoint, the problem of the ironless core armature in which the armature winding is sealed with the unsaturated polyester resin composition used at a relatively light load will be described.

The unsaturated polyester resin is a copolymerizable monomer solution of unsaturated polyester alkyd, and various additives are further added. These unsaturated polyester resins have serious drawbacks such as gelation during storage, changes with time in resin characteristics such as viscosity and curing characteristics, while they are viscous liquids, and fillers, reinforcing agents, pigments, low There is a handling difficulty when kneading a shrinking agent and the like all at once to obtain a resin composition.
In addition, unsaturated polyester resins are legally dangerous substances, and therefore their storage or storage must be legally regulated and special consideration must be given.

OBJECT OF THE INVENTION The present invention solves the problems in manufacturing an iron-free core armature that seals an armature winding with the unsaturated polyester resin composition described above, while maintaining the economical advantage over the epoxy resin. The aim is to simplify the winding sealing work.

Composition of the Invention The present invention comprises an unsaturated polyester alkyd / copolymerizable monomer (weight ratio 95/5 to 40/60) which is solid at room temperature, a polymerization initiator, a filler, and other additives to be added as necessary. A method for manufacturing a non-iron core armature in which an unsaturated polyester alkyd mixed powder is mixed below the softening temperature of the unsaturated polyester alkyd to form an unsaturated polyester alkyd mixed powder, and then extruded above the softening temperature to seal the armature winding.

The unsaturated polyester alkyd mixed powder that is solid at room temperature used in the present invention does not cause gelation at all, and does not change with time in resin characteristics, and can be stored for a long term which can be said to be almost indefinite. . In particular, if the unsaturated polyester alkyd is a pulverized product, it can be dissolved very easily in the copolymerizable monomer, and the copolymerizable monomer, the polymerization initiator, the filler and other additives to be added as necessary are not mixed. When the unsaturated polyester alkyd mixed powder is mixed at a temperature not higher than the softening temperature of the saturated polyester alkyd and extruded at a temperature not lower than the softening temperature, a resin composition for easily sealing the armature winding can be obtained. Moreover, the resin composition is exactly the same as the case where the unsaturated polyester resin is used in terms of the sealing property of the armature winding and the physical properties of the cured product. Therefore, the above-mentioned manufacturing method is advantageous in that the viscosity is easier to handle than the manufacturing method using the unsaturated polyester resin and the process is simplified, and the resin composition is formed immediately before the armature winding sealing. It is also possible to have optimum resin properties at that time, which is advantageous in maintaining the quality of the iron-free core armature.

The present invention will be described in more detail below.

The unsaturated polyester alkyd solid at room temperature referred to in the present invention is used for general unsaturated polyester resins. That is, it comprises an unsaturated dicarboxylic acid as a carboxylic acid component and optionally a saturated dicarboxylic acid, and a glycol component as an alcohol component. Unsaturated dicarboxylic acids include fumaric acid, maleic anhydride, itaconic acid, citraconic acid, etc., and saturated dicarboxylic acid components include orthophthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetra and hexahydrophthalic acid. . The glycol component is ethylene glycol, 1
-2- and 1.3-propanediol, 1.3- and 1.4-butanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, alkylene oxide adducts of bisphenols, hydrogenated bisphenols and their alkylene oxide additions Products, alkylene oxide adducts of halogenated bisphenols, 1 ・
4-cyclohexanedimethanol and the like. Such an unsaturated polyester alkyd has a softening point of room temperature or higher, preferably 80 to 100 ° C., and is a pulverized product. The pulverized product preferably has a particle size finer than 10 mesh practically.

One of the main components, the copolymerizable monomer, is styrene,
Examples include α-methylstyrene, vinyltoluene, divinylbenzene, monochlorostyrene and diallyl phthalate.

The unsaturated polyester alkyd solid at room temperature and the copolymerizable monomer are used in a weight ratio of 95/5 to 40/60. When the weight ratio is more than 95/5, there is a large friction when extruded as a resin composition, and it is impossible to extrude under uniform conditions due to this frictional heat. Furthermore, it is easy to deform the armature winding, etc. This is because it is disadvantageous in maintaining the motor characteristics. On the other hand, if this ratio is less than 40/60, the amount of low molecular weight substances is too much, so that the filler easily separates when the armature winding is sealed,
It is disadvantageous from the viewpoint of sealing property.

Next, the polymerization initiator used in the present invention generally needs to have a kick-off temperature, which is exhibited when curing these resins, higher than the softening temperature of the unsaturated polyester alkyd, specifically 15 A temperature higher than ℃ is desirable. That is, dicumyl peroxide, t-butyl perbenzoate, 2,5-dimethyl-2,5-dit (butyl peroxy) hexane and the like. In addition, it is preferable to add a granular filler such as calcium carbonate, talc, clay, or hydrated alumina as a filler as much as possible within a range not impairing the sealing property of the armature winding. Further, a reinforcing agent such as glass fiber, a releasing agent such as metal soap of higher fatty acid, a pigment such as carbon black, and a flame retardant such as antimony trioxide can be appropriately added as required.

The mixing ratio of the unsaturated polyester alkyd solid at room temperature and the copolymerizable monomer (weight ratio 95/5 to 40 to 60), the polymerization initiator, the filler, and other various additives to be added as necessary is determined by the electric machine. It is determined within a range that satisfies the characteristics and reliability of the iron-free core armature while considering the sealing property of the child winding. It should be noted that the mixing of each component is carried out below the softening temperature of the unsaturated polyester alkyd to give an unsaturated polyester alkyd mixed powder, but when the softening temperature is exceeded, the mixing becomes uneven and the quality of the ironless core armature cannot be maintained. Further, extruding the mixture at a temperature above the softening temperature of the unsaturated polyester alkyd is promptly an unsaturated polyester resin composition in the presence of 60 to 70% by weight or more of the filler, and further, this resin composition This is because it is necessary to maintain the stability of the product. Further, in order to smoothly extrude from the die or nozzle, it is preferable to extrude the mixture while applying a pressure of at least 30 Kgf / cm ² or more.

Description of Examples Next, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.

In the examples, "parts" means "parts by weight".

(Example) An unsaturated polyester alkyd pulverized product having a molecular weight of 14500 and a softening point of 92 ° C. obtained from an acid component consisting of 50 mol of terephthalic acid and 50 mol of fumaric acid, 90 mol of ethylene glycol, and 10 mol of 1.2-propylene glycol 75 Parts, diallyl phthalate monomer 25 parts, dicumyl peroxide 1 part, calcium carbonate 400 parts, glass fiber 30 parts, carbon black 1 part,
3 parts of zinc stearate were mixed below 50 ° C. When this unsaturated polyester alkyd mixed powder is supplied from a hopper equipped with a twin-screw cone type screw to a heating cylinder provided with an equal pitch single screw preheated to 100 ° C., a molten unsaturated polyester resin composition is obtained from a nozzle at the tip of the cylinder. Discharge. The figure is a characteristic diagram showing the relationship between the temperature of the resin composition and the torque applied to the blade when the molten resin composition is mixed by a roll type blade in a heated closed mixer. When the temperature is higher than the softening temperature of the unsaturated polyester alkyd, the temperature of the molten resin composition is much more stable than when the temperature is lower than the softening temperature. Incidentally, when the unsaturated polyester alkyd mixed powder is pushed in the cylinder at a pressure of about 30 Kgf / cm ² with the twin-screw type screw attached to the hopper, the unsaturated polyester resin composition is obtained in the screw in-line type injection machine, The armature winding can be sealed as it is. The surface runout of a flat coreless armature with a thickness of 2.0 mm and an outer diameter of 90 mm, in which an armature winding with a conductor diameter of 0.32 mm, 40 turns / coil, and 23 coils was sealed under the conditions of 170 ° C ± 5 deg × 60 sec.
0.07mm (n = 100), thermal shock (120 ℃ <->-30
(° C) x 10 times, with practically sufficient dimensional accuracy.

As a comparative example, terephthalic acid type unsaturated polyester resin
100 parts, dicumyl peroxide 1 part, calcium carbonate 4
A premixed unsaturated polyester resin composition was obtained by kneading together 00 parts, 30 parts of glass fiber, 1 part of carbon black, and 3 parts of zinc stearate with a kneader. Incidentally, the unsaturated polyester resin is viscous at 25 ° C. and 1500 Poise and is not handled well. Using this, an armature winding similar to that of the example was sealed by transfer molding at 170 ° C. ± 5 deg 90 sec to obtain a non-iron core armature. The surface runout of the obtained ironless core armature was 0.10 mm (n = 100), which had the same dimensional accuracy as that of the examples and the same thermal shock resistance.

As described above, the present invention uses a solid unsaturated polyester alkyd at room temperature and stores it as a mixed powder together with a copolymerizable monomer, a polymerization initiator and a filler. Since there is no day change and the unsaturated polyester resin composition can be prepared immediately before the sealing of the armature winding, it is easier to handle than the case where a viscous unsaturated polyester resin is used, and the process is simpler. It is advantageous in that it has optimum resin characteristics at that time, and the armature winding sealing property and the characteristics of the obtained ironless core armature are exactly the same as when using unsaturated polyester resin. There is an effect that it can be obtained stably.

[Brief description of drawings]

The figure is a characteristic diagram showing the relationship between the temperature of the molten resin composition and the screw rotation torque.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroaki Hirata 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 58-186348 (JP, A) JP 57-145555 (JP, A)

Claims (1)

[Claims] 1. An unsaturated polyester alkyd solid at room temperature, a copolymerizable monomer (weight ratio 95/5 to 40/60), a polymerization initiator and a filler are mixed at a temperature not higher than the softening temperature of the unsaturated polyester alkyd. To produce an unsaturated polyester alkyd mixed powder, and extruding the mixed powder at an extrusion temperature equal to or higher than the softening temperature of the unsaturated polyester alkyd to seal the armature winding.