JPH0640717B2 - Ironless armature - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an armature of a coreless motor that is widely used in copiers, automatic welding machines, NCI working machines, car air conditioners, OA, FA and electrical equipment fields. Relates to an ironless armature having a structure in which an armature winding formed of an insulated wire or a self-bonding insulated wire is sealed with a thermosetting resin composition and used at a relatively high temperature.

Structure of the conventional example and its problems The characteristics and reliability of the iron-free core motor usually depend largely on the performance of the armature part. Particularly in an ironless core armature in which an armature winding is formed of an insulated wire or a self-bonding insulated wire and is sealed with a thermosetting resin composition, the performance of the thermosetting resin composition is important. It has an influence.

For example, in a motor with a relatively large capacity of several watts to several kilowatts, it is possible to repeatedly start and stop frequently.
Alternatively, when the ambient temperature during use as a motor is high, the ironless core armature is usually used at a relatively high temperature of 150 to 180 ° C. Therefore, as for the ironless core armature, dimensional stability at the time of heat in such a relatively high temperature range, thermal rigidity, hot strength, and heat deterioration resistance are important in securing this type of motor characteristics and reliability. In order to satisfy these characteristics, for example, an armature winding sealed with an epoxy resin composition has been put into practical use. The epoxy resin composition is a composite composed of a filler, a mold release agent, and other additives added as necessary to the epoxy resin.

The reason why the above-mentioned epoxy resin is preferably used is that a cured product having excellent heat resistance, mechanical strength and chemical resistance can be obtained, and that it can be used as an insulated wire forming an armature winding or as a self-fusing insulated wire. This is because it has excellent abilities. Among them, the property that the epoxy resin cures comparatively slowly by ring-opening polymerization is advantageous for obtaining an ironless core armature with little curing strain and high dimensional accuracy and thermal shock resistance. In addition, since the melting viscosity at the time of sealing the armature winding is relatively low, it is easy to seal the armature winding with a precise structure, which is advantageous in maintaining the motor characteristics with less deformation of the armature winding. That's why. Furthermore, since the melt viscosity is relatively low, a relatively large amount of filler such as alumina, aluminum hydroxide, silica, zirconium silicate, etc. can be added, so that the conductor of the armature winding and the resin composition for sealing it can be The difference in thermal expansion is slightly reduced,
Alternatively, the thermal conductivity of the resin composition becomes relatively large, and various characteristics such as dimensional stability during heating, thermal rigidity, hot strength, and heat resistance characteristics as an ironless core armature even at a high temperature of 150 to 180 ° C. Is practically sufficient.

As described above, the epoxy resin and the compound with a large amount of the filler make the half-faced epoxy resin, which is a serious ironless armature constituent member, ensure relatively high curing and durability as a motor relatively slowly. The fact of progress has been a serious drawback to productivity from the viewpoint of armature winding sealing work. On the other hand, the unsaturated polyester resin is cured extremely rapidly because of a typical radical polymerization mechanism, and is extremely effective for improving productivity. However, the heat resistance of these unsaturated polyester resin cured products at a practical temperature is, for example, about 80 to 100 ° C. for phthalic anhydride type and about 150 ° C. for iriphthalic acid type or terephthalic acid type. In addition, the fact that it is fast-curing means an increase in curing strain, which is also a cause of seriously affecting the thermal shock resistance of the ironless core armature and the durability as a motor. In particular, when a fibrous filler is used as a constituent component of a cured resin product, the curing strain associated with polymerization curing overlaps with the fiber orientation, making it extremely difficult to ensure dimensional accuracy. Further, at the glass transition temperature or higher of the unsaturated polyester resin cured product, the influence of fiber orientation is likely to appear in the coefficient of thermal expansion and the like. Generally, the maximum glass transition temperature obtained from a cured product using an isophthalic acid-based or terephthalic acid-based styrene-based copolymerizable monomer is up to 170 ° C., so the iron-free armature temperature when used as a motor is 170 When the temperature exceeds ℃, the thermal expansion difference due to the fiber orientation overlaps the thermal expansion difference between the armature winding conductor and the thermal expansion anisotropy. It becomes difficult to maintain sex.

On the other hand, as a low shrinkage agent of the unsaturated polyester resin, for example, if various thermoplastic resins are used together, the dimensional accuracy at the time of armature winding encapsulation is extremely high, but as a coreless armature at high temperature, It becomes even more difficult to maintain and secure the characteristics and reliability of.

That is, the productivity of the ironless core armature and the characteristics and reliability of the motor are in conflict with each other.

OBJECT OF THE INVENTION The present invention is a thermosetting resin composition having extremely high heat resistance and thermal shock resistance in order to secure the characteristics and reliability as an iron-free core armature, in which polymerization and curing are extremely fast, and at least an armature winding. An attempt is made to provide a coreless armature that seals a portion.

Configuration of the Invention The configuration of the ironless core armature of the present invention is an armature winding portion and a resin composition for sealing the armature winding portion, and the resin composition is a composite consisting of the following groups a, b and c: Further, the group b is 70% by weight or more of the composite.

(a): An unsaturated polyester resin containing 5 to 40% by weight of a trifunctional triazine compound.

(b): an inorganic filler having a particle size of 20 μm or less and a particle size of 50
Inorganic filler of 70 μm or more (70/30 to 30/70 weight ratio) (c): Polymerization initiator, internal release agent, reinforcing agent, pigment and other additives added as necessary.

The present invention will be described in more detail below.

First, the armature winding referred to in the present invention is a winding group wound with an insulated electric wire or a self-bonding insulated electric wire, and its winding terminal is usually in a state of being electrically connected to a commutator. . The shape of such an armature winding can be selected from a flat shape to a cup shape based on the design concept of a coreless motor. Furthermore, the armature winding may include the commutator and the armature shaft that is an armature-constituting member.

The resin composition for sealing the armature winding referred to in the present invention is a composite consisting of the above-mentioned groups a, b and c, and the group b accounts for 70 to 85% by weight of the composite. Here, the group a is an unsaturated polyester resin containing 5 to 40% by weight of a trifunctional triazine compound.

The above unsaturated polyester resin is used by the present inventor in Japanese Patent Application No.
As proposed in 9-28950 (JP-A-60-174035), it is a copolymerizable monomer solution of an unsaturated polyester alkyd, and various additives such as a polymerization inhibitor are added if necessary. And contains at least 5 to 40% by weight of a trifunctional triazine compound. Here, the unsaturated polyester alkyd comprises an unsaturated dicarboxylic acid as a carboxylic acid component and optionally a saturated dicarboxylic acid, and a glycol component as an alcohol component. Fumaric acid as the unsaturated dicarboxylic acid,
Examples include maleic acid, itaconic acid, and citraconic acid. As the saturated dicarboxylic acid, orthophthalic acid, phthalic anhydride and the like can be used, but isophthalic acid, terephthalic acid, tetra- and hexahydrophthalic acid and the like are preferable.
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 adducts, alkylene oxide adducts of halogenated bisphenols, 1.
4-cyclohexanedimethanol and the like.

Although it is possible to appropriately use a vinyl-type or allyl-type copolymerizable monomer for the unsaturated polyester alkyd, the above-mentioned Japanese Patent Application No. 59-28950 (JP-A-60-1).
No. 74035), an unsaturated polyester resin containing 5 to 40% by weight of a trifunctional triazine compound is also used in the present invention.

The above trifunctional triazine compound is a compound having three allyl groups by adding allyl alcohol to the triazine ring, and examples thereof include triallyl isocyanurate and triallyl cyanurate. The triazine compound having three such allyl groups is 5% by weight in the unsaturated polyester resin.
In the following, the desired characteristics cannot be maintained as an ironless armature 4
If it is 0% by weight or more, the hardening strain becomes large, and the desired dimensional accuracy cannot be obtained, so that the thermal shock resistance and burnout characteristics of the ironless armature will be seriously affected.

On the other hand, the group b constituting the resin composition has a particle size of 20 μm.
It is composed of a mixture of m or less and 50 μm or more of inorganic particulate filler, and the mixing ratio thereof is in the range of 70/30 to 30/70 (weight ratio). When the mixing ratio of the inorganic particulate filler of 20 μm or less is 70 or more, the thermal shock resistance and burnout characteristics of the obtained ironless core armature are impaired, and when it is 30 or less, the dimensional stability and strength of the ironless core armature at the time of heating are remarkable. Be damaged.

As the above-mentioned inorganic granular filler, calcium carbonate fused quartz, clay, talf, zirconium silicate, alumina, aluminum hydroxide, silica sand, cold water stone and the like can be appropriately used.

On the other hand, the group c constituting the resin composition is a polymerization initiator of an unsaturated polyester resin belonging to the group a, or an internal release agent,
It refers to various additives used for smoothly encapsulating the armature winding of a composite composed of a and b groups such as a pigment and a reinforcing agent.

For example, as a polymerization initiator, dicumyl peroxide, t
-Butyl perbenzoate, 2.5-dimethyl-2.5
-Di-t (butylperoxy) hexane is used, internal fatty acids, higher alcohols, higher fatty acid esters or higher fatty acid esters and metal soaps are used as internal release agents, and glass fibers, organic fibers and the like are used as reinforcing agents. In addition to these, various additives such as carbon black and antimony trioxide, which normally constitute the thermosetting resin composition, may be appropriately used as necessary.

The mixing ratio of the resin composition consisting of the groups a, b and c is determined by the present inventor in Japanese Patent Application No. 59-23114 (Japanese Patent Laid-Open No. 60-
No. 167662), it is essential that at least b group occupy 70 to 80% by weight of the resin composition, and if it is less than 70% by weight, the thermal shock resistance and durability of the ironless core armature obtained are significantly impaired. Not only does it become difficult to maintain and maintain the desired dimensional accuracy, but if it is 85% by weight or more, the mechanical strength of the resin composition after curing decreases and the resin composition becomes brittle. In addition, a,
The mixing method of the b and c groups and the constituents of the resin composition appropriately selected from the a and c groups are determined within a range that satisfies the characteristics and reliability of the ironless core armature.

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.

The unsaturated polyester alkyd of the unsaturated polyester resin used terephthalic acid as the saturated dicarboxylic acid component and fumaric acid as the unsaturated dicarboxylic acid component. Triallyl isocyanurate as the trifunctional triazine compound, 2
Calcium carbonate was used as the inorganic filler of 0 μm or less and 50 μm or more, dicumyl peroxide was used as the polymerization initiator, glass chopped strand was used as the reinforcing agent, and higher fatty acid ester was used as the internal release agent. In addition, vinylon chopped strands, polyethylene powder, etc. were used as appropriate additives as needed.

The various constituent components belonging to the above-mentioned resin compositions a, b, c, and the group were kneaded together in a kneader in the proportions shown in Table 1 below. However, the numerical values shown in Table 1 are% by weight.

Separately, acid anhydride / diglycidyl ether bisphenol A type, acid anhydride / epoxy novolac type and poly-
Conventional Example 1 of an epoxy resin composition containing 80% by weight or 75% by weight of silica in each p-vinylphenol / diglycidyl ether bisphenol A epoxy resin
Prepared as ~ 4.

Next, a flat armature winding of 38 turns / coil, 23 segments is prepared using the self-bonding insulated electric wire.
Ironless core armatures made of the epoxy resin compositions according to the examples and comparative examples shown in the table and the separately prepared conventional example were manufactured by the transfer molding method. Here, the ironless core armature has an outer diameter of 94 mm and the thickness of the main magnetic flux linkage part of the armature winding part is 2.2 m.
m and the molding conditions were 160 ° C ± 5d in Examples and Comparative Examples.
eg, 3min, 100kgf / cm ² , and in the conventional example, 155 ° C ± 5deg,
After 5 minutes and 100 kgf / cm ² , it was further post-cured at 150 ° C. and 6 Hrs.

The thermal shock resistance of the ironless core armatures are collectively shown in Table 2 below. However, thermal shock is 120 ° C in advance in a hot air circulation type thermostat.
The operation of charging 10 iron-free core armatures each heated in above into methanol kept at −30 ° C. was repeated 10 times.

In Examples 1 to 10 and Comparative Examples 1 to 13 according to the present invention, the work of sealing the armature winding to form a coreless armature is extremely efficient as compared with the conventional example. In particular, since the unsaturated polyester resin contains the trifunctional triazine compound, the polymerization and curing are extremely fast, and the original physical properties can be secured without post-curing unlike the epoxy resin shown in the conventional example. In the case of Comparative Examples 1-13, the thermal shock resistance of the ironless core armature accompanying the increase in hardening strain due to rapid hardening is significantly impaired as shown in Table 2, and the motor characteristics are maintained. Is difficult.

Next, Examples 1 to 10, Comparative Examples 1 to 14 and Conventional Example 1
Using the ironless core armature of No. 4 as a motor, continuous free area operation with a DC 13.5V fan was performed in an atmosphere of 80 ° C. 1500
Tables 3 and 4 collectively show the state of the ironless core armature after the passage of Hrs. The initial temperature of the ironless core armature is 18
It is 0-185 degreeC.

As is apparent from Table 3, Examples 1 to 10 according to the present invention show motor characteristics in spite of the temperature of the ironless core armature reaching 180 to 185 ° C. as in the conventional example using the epoxy resin. It has been maintained for a long time. However, Comparative Examples 1 to 1
In No. 4, it is clear that an increase in hardening strain during manufacturing of the ironless core armature has a significant influence on maintaining the motor characteristics. Further, as is clear from Table 4, Examples 1 to 10 according to the present invention are similar to the conventional example even with respect to the abrasion of the brush, and the durability as a motor has practically sufficient characteristics. There is.

Effects of the Invention As described above, the present invention focuses on an unsaturated polyester resin that is extremely fast in polymerization and curing as a sealing resin for an armature winding,
In order to ensure its practical heat resistance, a trifunctional triazine compound is adopted, and the inorganic filler is 70% by weight or more of the cured resin of the sealing resin for the armature winding, and the particle size is 20μ.
70/3 or less of inorganic particulate filler having a particle size of m or less and 50 μm or more
Since it is set to 0 to 30/70 (weight ratio), the influence of curing strain due to polymerization and curing is eliminated, and it has the same thermal shock resistance as before and has stable motor characteristics for a long time at high temperature. A sustainable ironless armature can be obtained very efficiently.

Claims (1)

[Claims] 1. A thermosetting resin composition for sealing at least an armature winding portion, (a): an unsaturated polyester resin containing 5 to 40% by weight of a trifunctional triazine compound, and (b): An iron-free core armature comprising 70 to 85% by weight of an inorganic filler, (c): an additive, wherein the inorganic filler of the group (b) is an inorganic filler having a particle diameter of 20 μm or less and a particle diameter of 50 μm or more. An ironless armature, wherein the weight ratio of the inorganic filler is 70/30 to 30/70.