JP2002015928A - High-voltage transformer and ignition transformer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem the conventional high-voltage transformers that it is hard to firmly bond a high-voltage transformer coil bobbin formed of heat-resistant molded body to epoxy casting resin by a method, in which the thermal deformation temperature of a coil bobbin is 140 deg.C or higher in a high-voltage transformer having an output voltage of 10 to 35 kv, and then the coil bobbin is formed of a mixed material of a crystalline high-molecular compound and noncrystalline high-molecular compound, by which the coil bobbin is improved in adhesion to epoxy casting resin, so as to realize a small transformer which is high in heat resistance and stability. SOLUTION: A mixed material is composed of heat-resistant crystalline high- molecular compound and noncrystalline high-molecular compound, and the mixture material is loaded with inorganic filler to serve as bobbin material, by which epoxy casting resin forms a compatible layer with the noncrystalline high molecular compound contained in the surface of a bobbin formed of the bobbin material. Furthermore, the bobbin itself is improved in mechanical strength and regulated in thermal expansion coefficient by the crystalline high-molecular compound and inorganic filler, and as a result, the bobbin is bonded firmly to casting resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small high-voltage transformer comprising primary and secondary coils and a magnetic core.

[0002]

2. Description of the Related Art Small transformers, such as ignition transformers for automobiles and horizontal output transformers for driving CRTs, need a function of generating a special pulse-like high voltage having an output voltage of 10 kV to 35 kV. These are formed by assembling the primary and secondary coils and the magnetic core, then injecting and hardening a casting resin into the coil part, applying a special pulse voltage to the primary coil, This transformer outputs a high voltage by boosting with the next coil.

[0003] A direct ignition type automotive ignition transformer is
For example, a structure as shown in FIG. 1 is manufactured as follows. That is, the secondary coil (3) wound on the secondary bobbin (2) is arranged around the internal magnetic core A (1-1), and the primary coil (3) wound on the primary bobbin (4) is further arranged. 5), attach the internal magnetic core B (1-2) to both ends of the coil, and
Store in (6). Next, the casting resin (7) is put into the case, poured into the gap (8) in the transformer and the minute gap (9) in the coil, and then heat-cured. An external magnetic core (1-3) is wound around the case to complete the transformer.

A horizontal output transformer for driving a cathode ray tube is manufactured, for example, as shown in FIG. 2 as follows. That is, around the primary coil (5) wound on the primary bobbin (4), the secondary coil (3) wound on the secondary bobbin (2) via the interlayer material (10) is arranged, The case (6) is fitted in these. Next, the casting resin (7) is put into the case, poured into the gap (8) in the transformer and the minute gap (9) in the coil, and then heat-cured. Insert the magnetic core (1) to complete the transformer.

[0005] These transformers need to generate a predetermined function for a long period of time in a high temperature atmosphere in a narrow space inside the apparatus, and may be left in a low temperature and high humidity atmosphere. Sex is desired.

In this type of high-voltage transformer, the combination of the casting resin and the bobbin material is important, and the adhesion is insufficient, and peeling occurs between the two or the thermal expansion coefficients of the two do not match. If the constituent material cracks due to the applied thermal stress, there is a danger that the coil itself will be electrically broken down by the discharge. Further, the withstand voltage of the bobbin material and the casting resin itself is also required.

Conventionally, from the viewpoint of preventing dielectric breakdown, a combination excellent in the adhesiveness between the cast resin and the bobbin material has been selected. As the cast resin, an epoxy resin having a heat deformation temperature of 90 ° C. to 120 ° C. and a bobbin material have been used. Polyphenylene oxide and polystyrene mixed composition having a heat distortion temperature of about 120 ° C. (for example, G
E company, brand name Noryl) was widely used.

[0008] It has been used that the surface of the noril material partially swells when it comes into contact with a liquid epoxy resin, and forms a strong adhesive layer with the curing of the epoxy resin.

[0009]

According to these conventional methods, the epoxy resin used and the bobbin material have low thermal deformation temperatures, so that when the high-voltage transformer is placed in a high-temperature atmosphere of 120 ° C. or higher, the components are softened. This causes a problem of causing electrical breakdown and mechanical deformation of the material itself. In automotive ignition transformers, to improve power controllability,
In place of the conventional distributor system in which power is distributed from one transformer to a plurality of engine units, a system in which a plurality of transformers are directly connected to the same number of engine units is being introduced. In a horizontal output transformer for driving a CRT, a display is used. There is a need to reduce the weight and cost of the products. In each case, the transformer is downsized and the heat resistance is 1
It is necessary to increase the temperature from a level of 20 ° C. or less to a range of 120 ° C. to 220 ° C.

However, since the conventional transformer has only a limited combination of materials, it has been impossible to cope with a severe use condition and a demand for downsizing of parts. If an epoxy resin or a general bobbin material having a high heat deformation temperature is used to improve the heat resistance of the coil, the adhesion between the two cannot be secured, and it is also difficult to match the thermal expansion coefficients between the two.

An object of the present invention is to solve these conventional problems and to obtain a compact, heat-resistant, low-cost high-voltage transformer.

[0012]

SUMMARY OF THE INVENTION A feature of the present invention is that a transformer comprising a primary coil, a secondary coil, and a magnetic core is obtained by casting and hardening a casting resin in a coil portion, and has an output voltage of 10 kV to 35 kV. , Wherein the heat deformation temperature of the casting resin is 130 ° C. or more, and the heat deformation temperature of the coil bobbin is 140 ° C. or more.

The heat deformation temperature indicates the temperature at which the cast resin cured product and the bobbin molded product start to be deformed when left standing at a high temperature. For convenience, a load of 1.82 MPa is applied according to ASTM D648. Can be replaced with the measured value. However, in an actual transformer, deformation may start at a temperature 10 to 20 ° C. lower than the value of ASTM D648. Since bobbin moldings are made of thermoplastic resin, large deformation occurs immediately after deformation starts.However, since epoxy cast resin is a thermosetting resin, even if it exceeds the heat deformation temperature, it will immediately undergo significant deformation. I can't. 120 ℃ high voltage transformer
For the purpose of practical use as described above, considering the margin, the heat deformation temperature of the epoxy cast resin is 130 ° C. or more, and the heat deformation temperature of the bobbin material is 10 ° C. higher than that of the epoxy cast resin. The temperature was set to 140 ° C. or higher.

As the casting resin, an epoxy resin containing an inorganic filler is used. The inorganic filler contained in the casting resin is quartz or quartz glass or a mixture of quartz and quartz glass, and if necessary, other inorganic fillers such as alumina, hydrated alumina, and calcium carbonate are added to improve the properties. be able to.

In order to maintain the heat distortion temperature of the cast resin at 130 ° C. or higher, bisphenol A diglycidyl ether and bisphenol F diglycidyl ether are used as main agents for epoxy resins. The addition of an epoxy compound is effective.

The alicyclic epoxy compound has a relatively low viscosity before curing and has an action of improving the heat distortion temperature of the cured epoxy product. Examples thereof include cyclohexene oxide and 3,4-epoxycyclohexylmethyl-3. , 4-epoxycyclohexanecarboxylate and the like.

As a curing agent for an epoxy resin, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and hexahydrophthalic anhydride are useful. In particular, methylhexahydrophthalic anhydride and hexahydrophthalic anhydride increase the heat distortion temperature of the epoxy cured product.

Examples of the curing accelerator for epoxy resins include imidazoles, especially 2-ethyl-4-methylimidazole and its acrylonitrile adduct, 1-methyl-2-ethylimidazole.

There are various types of inorganic fillers for casting resin, such as quartz, quartz glass, alumina, hydrated alumina, calcium carbonate, talc, mica, and general glass spheres. In consideration of the above, it is desirable to use quartz or quartz glass or a mixture of quartz and quartz glass as a main component. This makes it possible to maintain the coefficient of thermal expansion at a level close to the value of the coil bobbin while ensuring the electrical insulation of the cast resin.

The inorganic filler for the casting resin is added in an amount of 20% by weight to 55% by weight. More preferably, the inorganic filler is added in an amount of 30 to 50% by weight. 20% by weight
Below, the difference between the coefficient of thermal expansion of the cast resin and the bobbin material becomes large, causing problems such as cracking of the cast resin cured product in the transformer. When the content is 55% by weight or more, the viscosity of the cast resin becomes high, and it becomes difficult to inject the cast resin into the transformer.

As the coil bobbin, a mixture of a crystalline polymer and a non-crystalline polymer is used. An inorganic filler is contained in these polymer mixtures. When a non-crystalline polymer is mixed with a crystalline polymer and various inorganic fillers are added, a heating mixer is used so that both polymers can be forcibly mixed in a molten state. It is desirable to form these polymer mixtures once into pellets and then into various shapes using an injection molding machine.

As the material for the coil bobbin, a mixture of a crystalline polymer and an amorphous polymer containing an inorganic filler is used. This material is a heat-resistant polymer material that can be injection molded and has a heat deformation temperature of 140 ° C. or higher.

The polymer material constituting the coil bobbin is not particularly limited as long as it has a heat deformation temperature of 140 ° C. or higher. Examples of the crystalline polymer include polyphenylene sulfide resin, polyether nitrile resin, and polybutylene terephthalate. Resin, liquid crystal polymer resin,
Examples of the non-crystalline polymer include polyetherimide resin, polyethersulfone resin, polysulfone resin, and polycarbonate resin.

The crystalline polymer mentioned here does not swell even if it is in contact with a liquid epoxy resin for a long time. On the other hand, when the amorphous polymer comes into contact with the liquid epoxy resin at the time of casting or during the curing process, the surface portion dissolves with the epoxy resin to form a compatible layer.

The inorganic filler contained in the coil bobbin is mainly made of glass fiber, and if necessary, other inorganic fillers such as talc, mica, general glass spheres, quartz, quartz glass, alumina, calcium carbonate, etc. are added. Characteristics such as electrical insulation, thermal expansion coefficient, mold damage, and price can be improved.

The inorganic filler for the coil bobbin is contained in an amount of 20 to 55% by weight based on the bobbin material. More preferably, the inorganic filler is contained in an amount of 30 to 50% by weight. If the content is 20% by weight or less, the adhesiveness between the cast resin and the bobbin material is poor, and problems such as peeling and cracking of the cast resin cured product in the transformer occur. When the content is 55% by weight or more, the formability of the bobbin is inferior.

Generally, a polymer molded article (11) and an epoxy resin
In order to improve the adhesion with (12), as shown in FIG.
Three methods are conceivable.

The first method is to form a strong bond by reacting a molded body (11) made of a reactive polymer (13) with an epoxy resin (12). If necessary, an inorganic filler (14) such as glass fiber is blended into the molded body. In this method, there is a problem that it is difficult to obtain a heat-resistant reactive polymer that can be used, and the material itself becomes expensive.

In the second method, an inorganic filler (15) which easily adheres to the epoxy resin (12) is blended in the polymer molded body (11),
The inorganic filler (15) and the epoxy resin (12) are bonded to ensure strong adhesion. If necessary, an inorganic filler (14) such as glass fiber is blended into the molded body. This method can be implemented relatively easily,
There are problems that it is difficult to maintain the adhesion between (16) and the inorganic fillers (14) and (15), and that the adhesion to the epoxy resin is reduced when the surface of the molded body is contaminated.

In the third method, the amorphous polymer (18) and the epoxy resin (12) in the polymer molded body (11) are partially compatible with each other so as to have molecular entanglement. A layer (17) is made to ensure strong adhesion. As the heat-resistant polymer applicable to this method, conventionally, only a material having a heat distortion temperature of 140 ° C. or lower is known and cannot be used for applications requiring heat resistance. In the present invention, the above amorphous polymer (18) has a heat distortion temperature of 1
Utilizing the fact that it has been found that it has a heat resistance of 40 ° C. or higher and forms a compatible layer with an epoxy resin.

The reason that the crystalline polymer (19) is blended with the non-crystalline polymer (18) is to improve the fluidity during molding, to improve the adhesive strength and mechanical strength, and to reduce the price. is there. Some crystalline polymers have a lower viscosity in the fluid state than non-crystalline polymers, and those containing crystalline polymers are easier to mold, making them suitable for manufacturing thin, long, heat-resistant molded products. I have.
In addition, the addition of an inorganic filler (14) such as glass fiber to a mixture of a non-crystalline polymer and a crystalline polymer, in addition to improving the adhesive strength and mechanical strength, reducing the price, It can be used to match the coefficient of thermal expansion of the molding with the epoxy casting resin.

The combination of the above-mentioned cast resin containing an inorganic filler and a bobbin using a heat-resistant polymer material makes it possible to exhibit the performance of a high-voltage transformer.
By treating the bobbin surface, the reliability of the transformer can be ensured and the service life can be further extended. That is, conventionally known methods such as sandblasting, oxygen plasma treatment, ultraviolet ozone treatment, and corona discharge treatment can be used on the surface of the coil bobbin.

[0033]

Next, embodiments of the present invention will be described in detail.

Example 1: Compound containing bisphenol A diglycidyl ether and an alicyclic epoxy compound as main components as epoxy resin, mixture of methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride as curing agent, curing accelerator 60 containing imidazole
A liquid epoxy casting resin composition comprising 40% by weight of an equal amount of quartz and quartz glass as the inorganic filler was prepared based on the weight%. Epoxy resin, curing agent,
By selecting the compounding ratio of the curing accelerator, it is possible to obtain a composition exhibiting a predetermined heat deformation temperature when cured by heating.

Further, plastic molded plates of various compositions and Al rods to be adhered to the plastic molded plates were prepared. The plastic plate is cut out to a thickness of 3 mm, length 12 mm, width 12 mm, Al bar is length 18 mm,
It was cut out to 3.6 mm in diameter (0.1 square cm in cross section). Place the epoxy resin composition prepared in advance in the center of the plastic plate, heat the whole in a heating furnace with the Al bar standing on it, cure the epoxy resin composition, and bond the plastic plate and the Al bar I let it. Curing of the cast resin was performed by raising the temperature from around room temperature, but the final curing conditions were strictly controlled. The adhesive strength was measured by fixing the plastic plate horizontally and lifting the Al bar vertically.

Table 1 shows the selection of plastic plates. The conditions and adhesiveness of the cast resin and plastic plate are shown. The adhesion was shown in terms of the state of the test piece after curing of the epoxy resin before the test, the bonding strength at the time of the bonding test, and the breaking state of the plastic plate after the test.

The comparison Nos. 1 to 9 in Table 1 show the levels of the conventional products. ASTM D648 as coil bobbin material (measuring load: 1.8
2MPa) A polyphenylene oxide and polystyrene mixture composition (PPO composition, for example, Noryl, trade name, manufactured by GE) having a heat distortion temperature of 100 to 139 ° C has been widely used.

When the epoxy resin was cured under the final curing conditions of 100 ° C./3 h (Comparative No. 1), the PPO composition did not show any deformation of the plate itself, but it was necessary to keep the thermal deformation temperature of the epoxy resin high. When cured at a high temperature of 120 ° C to 150 ° C, the plate itself deformed (Comparative Nos. 2 to 3). However, a plate containing an inorganic filler has a large adhesive strength, and a broken state also causes cohesive failure of the plate itself.

Polyphenylene sulfide (PPS, for example, manufactured by Polyplastics Co., Ltd., product name: FORTRON) causes plate deformation when there is no inorganic filler (Comparative No. 4) and has a low adhesive strength, but the inorganic filler does not. Enter (Comparative No. 5 and
6) The bonding strength is improved, and the destruction state becomes cohesive failure from the interface.

Polyetherimide (PEI, for example, Ultem, manufactured by GE) has minute voids and cracks at the portion in contact with the epoxy resin. The fracture state was cohesive failure, and the one containing the inorganic filler (Comparative No. 8) had higher adhesive strength than the one without the inorganic filler (Comparative No. 7).

A molded plate obtained by mixing PPS with PEI (Comparative No. 9) has no deformation of the plate and causes cohesive failure, but has an adhesive strength of 20 MPa.
Above target values suitable for high-voltage transformer applications are somewhat lacking. The molded plates (Execution Nos. 1 and 2) obtained by adding PEI to PPS and further adding an inorganic filler are in a good state before the test, and the bond strength and the fracture state satisfy the target.

[0042]

[Table 1]

Example 2: The adhesiveness between a plastics molded product whose surface was contaminated with a release material and an epoxy resin was examined.

Table 1 shown in Example 1 Comparison No. 6 and Example N
A plastic molded article similar to o.2 was immersed in a toluene solution of silicone oil and then pulled up, and the toluene was sufficiently dried to prepare a model sample whose surface was contaminated with silicone oil, and an adhesion test was performed.

The molded plate according to the present invention is as shown in Table 2 No. 2,
As shown in 2-1 and 2-2, it has stable adhesiveness even if the surface is contaminated. On the other hand, Table 2 Comparison No. 6 comparison of contaminated products
Nos. 6-1 and 6-2 show a decrease in adhesiveness.

[0046]

[Table 2]

Example 3 A molded plate was prepared by changing the blending ratio of the crystalline polymer PPS and the non-crystalline polymer PEI with respect to the glass fiber added at 30% by weight, and Table 1 of Example 1 No. 2 An adhesion test was performed in the same manner as in the above, and the results shown in FIG. 4 were obtained.

When the content of the non-crystalline polymer PEI with respect to the total amount of the crystalline polymer PPS and the non-crystalline polymer PEI is 10 to 90% by weight, abnormalities in the adhesion test piece and interfacial destruction after the adhesion test may occur. However, it showed an adhesive strength of 20MPa or more suitable for high-voltage transformer applications.

Further, the same adhesion test piece as that used in FIG. 4 was used to observe the cross-section of the bonded portion with an SEM and a micro infrared analyzer.
An epoxy resin compatible layer of 0.5 to 20 microns was detected.

Example 4: In the same manner as in Example 1,
An epoxy cast resin composition having a final curing of 150 ° C. for 3 hours and a heat distortion temperature of 150 ° C. was prepared.

Further, as a high voltage transformer for casting the above resin composition, a direct ignition type automobile ignition transformer having the structure as shown in FIG. 1 was prepared. This transformer is 22mm in diameter and 100mm in length, 1mm in diameter and 90mm in length.
The secondary coil has a secondary coil with a diameter of 15 mm and a length of 90 mm.
The primary and secondary bobbins made of various materials were molded and then subjected to a predetermined winding to form primary and secondary coils, respectively.

Internal magnetic core (1-1, 1-2), secondary bobbin (2)
After assembling the coil (3), the primary bobbin (4) and the coil (5), the case (6), the whole was heated and dried in a heating furnace at 115 ° C.
Adhered water was removed. This was placed in a vacuum, and a liquid epoxy casting resin composition (7) prepared in advance was injected. Curing of the cast resin was performed by raising the temperature from around room temperature, but the final curing conditions were strictly controlled. The outer magnetic core (1-3) was fitted on the outside of the case (6) to obtain a completed ignition transformer.

The initial state of the transformer was determined by visual inspection and electrical rating operation. In addition, this transformer is
The transformer was subjected to a thermal shock test with 1 h and 130 ° C. for 1 h, and the operation of the transformer was tested for each cycle to check the insulation breakdown. The point at which dielectric breakdown inside the transformer is electrically detected is indicated as life.

Table 3 shows the selection status of the casting resin and the composition of the bobbin material. The conditions of the casting resin and the bobbin when manufacturing the transformer and the characteristics of the transformer are shown. In Comparative No. 10 in Table 3, since the amount of the inorganic filler in the cast resin was small, the expansion coefficient of the coil including the bobbin did not match, and the cast resin cracked. Also, compare No.11
As shown in (1), if the amount of the inorganic filler in the casting resin is too large, the viscosity becomes too high, and poor injection occurs when the casting resin is injected into the transformer. As shown in execution Nos. 3 to 7, when the amount of the inorganic filler in the casting resin is 20 to 55% by weight,
The transformer as a product has a thermal shock life of 300 cycles or more, meeting the target.

In Comparative No. 12, since the amount of the inorganic filler in the bobbin material was small, the coefficient of thermal expansion of the cast resin did not match, and the cast resin and the bobbin peeled off during the thermal shock test. At the 10th cycle, electrical breakdown occurred. Also, compare No.13
As shown in (1), when the amount of the inorganic filler in the bobbin is too large, molding defects such as insufficient flow occur. As shown in Examples 8 to 10, when the amount of the inorganic filler in the bobbin is 20 to 55% by weight, the transformer as a product has a thermal shock life of 300 cycles or more.

[0056]

[Table 3]

Example 5: In the same manner as in Example 1,
It is composed of 60% by weight of epoxy resin, 30% by weight of quartz and 30% by weight of quartz glass.
An epoxy casting resin composition at 55 ° C. was prepared.

In the same manner as in Example 4, a direct ignition type automobile ignition transformer was prepared, and a liquid epoxy casting resin composition prepared in advance was injected and cured to obtain a completed ignition transformer. Obtained.

As shown in Table 4, the initial state and the thermal shock life of the ignition transformer having different types of bobbins were determined.

Comparative Nos. 14 to 17 are non-crystalline polymers such as polyetherimide resin (PEI), polyethersulfone resin (PES, manufactured by Mitsui Chemicals, Inc.) and polysulfone resin (PS
U, for example, Teijin Acomo Co., Ltd., trade name Udel), bobbin made of polycarbonate resin (PC, for example, Teijin Limited, trade name Panlite), Comparative Nos. 18 to 21 are polyphenylene sulfide resins that are crystalline polymers (PPS), polyether nitrile resin (PENi, for example, manufactured by Idemitsu Material Co., Ltd.), polybutylene terephthalate resin (PBT, for example, manufactured by BASF, trade name Ultradur), liquid crystal polymer (LCP, for example, manufactured by Polyplastics Co., Ltd.) The characteristics of an ignition transformer using a bobbin made of Vectra (trade name) are shown.

The ignition transformer using PSU (Comparative No. 16) and PC (Comparative No. 17) as bobbins was inoperable due to cracking of the bobbin during the injection of epoxy cast resin and curing. Other ignition transformers (Comparative Nos. 14, 15 and Nos. 18-21) were good in the initial state, but when subjected to a thermal shock test, they were electrically destroyed and did not reach the target 300 cycles. .

The ignition transformer using the bobbin according to the present invention composed of a crystalline polymer, an amorphous polymer and an inorganic filler (Nos. 11 to 17) was subjected to not only the initial state but also a 300-cycle thermal shock test. After that it worked fine.

[0063]

[Table 4]

Example 6: In the same manner as in Example 1,
It is composed of 60% by weight of epoxy resin, 30% by weight of quartz and 30% by weight of quartz glass.
An epoxy casting resin composition at 55 ° C. was prepared.

As the high voltage transformer, a horizontal output transformer for driving a cathode ray tube having the structure as described in FIG. 2 was prepared. This transformer is 40mm in diameter, 52mm in length and 17mm in diameter
It has a primary coil of 45 mm in length and a secondary coil of 30 mm in diameter and 30 mm in length. The primary and secondary bobbins made of various materials were molded and then subjected to a predetermined winding to form primary and secondary coils, respectively.

Outside the primary bobbin (4) and the coil (5), the secondary coil (3) wound into the secondary bobbin (2) through the interlayer material (10) made of a polyimide film is fitted. After assembling (6), the whole was heated and dried in a heating furnace at 115 ° C. to remove adhering moisture. This was placed in a vacuum, and a liquid epoxy casting resin composition (7) prepared in advance was injected. Curing of the cast resin was performed by raising the temperature from around room temperature, but the final curing conditions were strictly controlled. The magnetic core (1) was inserted through the center of the primary bobbin (4) to obtain a finished horizontal output transformer.

The initial state of the transformer is appearance inspection and rated output
The determination was made by electrically measuring a 25 kV flyback pulse. Further, the transformer was subjected to a temperature cycle test in which one cycle was -40 ° C for 1 hour and 130 ° C for 1 hour. At each cycle, the transformer was subjected to a rated operation test, and the state of electrical breakdown inside the transformer was checked.

Table 5 shows the initial state and the thermal shock life of the horizontal output transformer having different types of bobbins.
PPO composition (Comparative No. 22), PSU (Comparative No. 24), PC (Comparative No. 2)
The horizontal output transformer using 5) as a bobbin could not be operated due to the deformation of the bobbin or the cracking of the bobbin during the injection of epoxy cast resin and curing. Other horizontal output transformers (Comparison No. 2
3. In the comparison Nos. 26 to 27), the initial state was good, but when subjected to the thermal shock test, it was electrically broken and did not reach the target 300 cycles.

The horizontal output transformer (embodiments Nos. 18 to 22) using a bobbin according to the present invention comprising a crystalline polymer, a non-crystalline polymer, and an inorganic filler is not only in the initial state, but also in the initial state.
It also worked properly after the cycle thermal shock test.

[0070]

[Table 5]

Example 7 A direct ignition type automobile ignition transformer (11) as shown in FIG. 3 was formed by using the casting resin and the bobbin shown in Table 3 No. 5. This ignition transformer (2
0) has a diameter of 22 mm and a length of 130 mm. This is 2
Primary bobbin (2) and coil (3), primary bobbin (4) and coil (5),
The inner magnetic cores (1-1, 1-2) and the outer magnetic cores (1-1) are attached to the case (6) and the coil part (12) made of epoxy cast resin (7).
3) is arranged. The signal entering the input section (21) is boosted to a high voltage of about 15 kV at the peak by the coil section (23) through the control circuit (22), and then from the output section (25) through the rectification section (24). Is output. The ignition transformer (20) is connected to a spark plug (30) arranged in a combustion cylinder (29) together with an intake port (26), an exhaust port (27), a control valve (28), and the like, in the engine to form a plug hole. Used in (31).

This ignition transformer normally operates with a pulse waveform of an output voltage of 20 kV for 1000 hours or more even when continuously operated at 150 ° C.

[0073]

As described above, according to the present invention, the adhesiveness between the bobbin of the high-voltage transformer and the casting resin can be highly assured. As a result, the operating characteristics under severe temperature cycle conditions are secured, and a small high-voltage transformer with high heat resistance and high reliability can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an automotive ignition transformer.

FIG. 2 is an explanatory diagram of a CRT driving horizontal output transformer.

FIG. 3 is an explanatory view of the state of adhesion between a polymer molded body and an epoxy resin.

FIG. 4 is a view showing the adhesive strength between a polymer molded body and an epoxy resin.

FIG. 5 is a diagram showing a practical state of an automotive ignition transformer.

[Explanation of symbols]

1-1: Internal magnetic core A, 1-2 ... Internal magnetic core B, 1-
3 ... external magnetic core, 2 ... secondary bobbin, 3 ... secondary coil, 4
... Primary bobbin, 5 ... Primary coil, 6 ... Case, 7 ... Cast resin, 8 ... Transformer gap, 9 ... Coil gap, 10
... interlayer material, 11 ... polymer molded body, 12 ... epoxy resin,
13: reactive polymer, 14: inorganic filler, 15: adhesive inorganic filler, 16: polymer material, 17: compatible layer, 18
... Amorphous polymer, 19 ... Crystalline polymer, 20 ... Ignition transformer, 21 ... Input unit, 22 ... Control circuit, 23 ... Coil unit, 24 ... Rectifier unit, 25 ... Output unit, 26 ... Suction port, 27
... Exhaust port, 28 ... Control valve, 29 ... Combustion cylinder, 30 ... Spark plug, 31 ... Plug hole.

Continued on the front page (72) Inventor Kazutoshi Kobayashi 2520 No. Odaiba, Hitachinaka City, Ibaraki Prefecture Within the Hitachi, Ltd. Automotive Equipment Group (72) Inventor Makoto Iida 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd. F term in the Manufacturing Technology Laboratory (Reference) 4J002 CF07W CF18W CG00X CH02W CM04X CN01W CN03X DL006 FA046 FD016 GQ00

Claims (8)

[Claims] 1. A transformer having a primary coil, a secondary coil and a magnetic core, obtained by casting and curing a casting resin in a coil portion, and having an output voltage of 10 kV to 35 kV, wherein a heat deformation temperature of the coil bobbin is 140 ° C. The casting resin is an epoxy resin, the coil bobbin is made of a mixture of a crystalline polymer and an amorphous polymer, and the weight ratio of the crystalline polymer to the amorphous polymer is from 1 to 9 A high voltage transformer characterized by a 9: 1 ratio. 2. A transformer having a primary coil, a secondary coil, and a magnetic core, obtained by casting and hardening a casting resin in a coil portion, and having an output voltage of 10 kV to 35 kV. 140 ° C or higher, coil bobbin heat deformation temperature is 1
30 ° C. or higher, the casting resin is an epoxy resin, the coil bobbin is made of a mixture of a crystalline polymer and an amorphous polymer, and the weight ratio of the crystalline polymer to the amorphous polymer is 1: 1. A high voltage transformer characterized in that the ratio is 9 to 9: 1. 3. The casting resin according to claim 1, wherein the inorganic filler is 20% by weight to 55%.
Claims 1 and 2 wherein the coil bobbin comprises a mixture of a crystalline polymer and an amorphous polymer containing from 20% to 55% by weight of an inorganic filler. Item 2. The high voltage transformer according to Item 2. 4. The high-voltage transformer according to claim 3, wherein the inorganic filler contained in the casting resin is made of quartz, quartz glass, or a mixture of quartz and quartz glass. 5. The high-voltage transformer according to claim 3, wherein the inorganic filler contained in the coil bobbin is made of glass fiber or a mixture containing glass fiber. 6. The crystalline polymer constituting the coil bobbin is polyphenylene sulfide resin, polyether nitrile resin, polybutylene terephthalate resin, liquid crystal polymer resin, and the non-crystalline polymer is polyether imide resin, polyether sulfone resin, polysulfone. 3. The high-voltage transformer according to claim 1, wherein the high-voltage transformer is a resin or a polycarbonate resin. 7. The high voltage transformer according to claim 1, further comprising a compatible layer formed when the epoxy resin is cured after being compatible with the surface of the coil bobbin. 8. An ignition transformer having the high-voltage transformer according to claim 1.