JP6003484B2 - Corona-resistant insulating member and article using the same - Google Patents

Description

  The present invention drastically improves the corona resistance, which deteriorates over time due to the occurrence of partial discharge such as corona discharge and arc discharge when used under high voltage, and does not eventually lead to dielectric breakdown. The present invention relates to an insulating member and various articles using the insulating member as a member. The corona-resistant insulating member of the present invention can be advantageously used in an ignition coil used in an internal combustion engine such as a vehicle engine.

  In an ignition coil used for an internal combustion engine such as a vehicle engine, a primary coil (primary coil) and a secondary coil (secondary coil) wound around an inner peripheral side and an outer peripheral side around the same axis line For example, a high voltage of 20 to 40 kV is generated in the secondary coil using the electromagnetic induction action. The high voltage generates a spark between a pair of electrodes in the spark plug connected to the secondary coil, and a combustion operation in the internal combustion engine is performed by the spark.

  It has been proposed to use various insulating members for the ignition coil. However, in the case of general-purpose resin materials, there is a drawback that the chemical / thermal stability is low and the reliability is insufficient. In addition, ceramic materials are disadvantageous in that they are heavy, lack toughness, have low mechanical strength, and need to be exposed to high temperatures during production, resulting in high production costs. PPS (polyphenylene sulfide) resin, PBT (polybutylene terephthalate) resin, PET (polyethylene terephthalate) resin, PPE (polyphenylene ether) resin, epoxy resin so that it can withstand high voltages as well as not suffer from such drawbacks Are used in modern ignition coils.

  As an example, Patent Document 1 discloses that the ignition coil case and the primary bobbin are molded using PPS resin instead of the conventional PBT resin, thereby reducing the size of the ignition coil without impairing the output energy. The illustrated ignition coil for an internal combustion engine is described.

  By the way, in recent years, as a vehicle engine or the like, a high output, low fuel consumption, low emission engine has been developed, and a required voltage for an ignition system is increasing year by year. Therefore, also in the insulating member used for the ignition coil, it is necessary to improve the corona life (durability) that can withstand a high voltage for a long time, and further contrivance is required for the material to be used.

  In order to meet the above demand, Patent Document 2 discloses an insulating member used for an ignition coil having a primary coil and a secondary coil, and the insulating member performs a dehydration decomposition reaction on an insulating material serving as a base. An insulating member for an ignition coil characterized by adding a dehydrating decomposition reagent to be generated is described.

  Patent Document 3 discloses a primary coil obtained by winding a primary winding a plurality of times, a secondary coil obtained by winding a secondary winding having a wire diameter of 30 to 100 μm a plurality of times, and a wire of the primary winding. An ignition coil for an internal combustion engine is described which has a resin molded body that impregnates between the intermediate winding and the secondary winding and seals the primary coil and the secondary coil. In this internal combustion engine ignition coil, the resin molded body is made of 65 fillers composed of 60% by weight or more of spherical silica and 40% by weight or less of crushed silica in order to suppress the progress of electric trees in the resin molded body. It is characterized by containing from 80% by weight to 80% by weight.

JP-A-8-339928 JP 2008-166365 A JP 2009-278074 A

  However, the above prior art still has problems to be solved. For example, in the case of an insulating member for an ignition coil described in Japanese Patent Application Laid-Open No. 2008-166365, the improvement of corona resistance is achieved by adding a dehydration decomposition reaction agent. Since the width is not large, further improvement is required. Moreover, since the mechanism for improving the corona resistance depends on the dehydration decomposition reaction, the improvement in the corona resistance at the product use temperature (usually a high temperature around 130 ° C.) is small. In addition, in the case of an ignition coil for an internal combustion engine described in Japanese Patent Application Laid-Open No. 2009-278074, the life of the corona is extended by adding an inorganic filler as a filler, but the matrix for blending the filler is a resin. As such, the chemical stability is low and the improved corona resistance achieved is inferior to ceramic materials. The term “corona resistance” means that when used in this specification, the material deteriorates with time even when it is exposed to partial discharge such as corona discharge and arc discharge. This means that the material or a member formed from the material has sufficient resistance to be used stably and with high reliability over a long period of time without suffering dielectric breakdown or the like.

  The object of the present invention is therefore to have good chemical / thermal properties in addition to having a corona life (excellent durability) that can withstand high voltages for long periods of time and prevent deterioration over time due to partial discharges. It is an object of the present invention to provide a novel insulating member useful for manufacturing an ignition coil or the like, which is highly reliable in corona resistance due to stability, is lightweight and tough, and can be provided at low cost.

  The object of the present invention is to dramatically increase the reliability by using as a member a novel insulating member that can prevent deterioration with time and dielectric breakdown due to partial discharge due to excellent corona resistance, The object is to provide various articles including an ignition coil for automobiles.

  Other objects of the present invention will be readily understood from the following detailed description.

  The inventors of the present invention have paid attention to improving corona resistance by reversely using the energy generated by the discharge that has caused the deterioration of the resin. As a substance capable of forming an inorganic substance that can contribute to the improvement of corona resistance by receiving energy from electric discharge in the surface resin (one side or both sides) or in a matrix resin of an insulating member made of resin, “inorganic insulating coating forming silicon” It is effective to apply "containing material" or "inorganic insulating substance-forming silicon-containing material" (in the present invention, these silicon-containing materials may be collectively referred to simply as "precursor"). Knowledge was obtained and the present invention was completed.

  Specifically, in the present invention, the insulating member is not formed of a single resin, but is formed in the form of a composite insulating member from a main body made of a base resin and an inorganic insulating coating covering the main body. Here, the inorganic insulating coating uses the energy by partial discharge, which has been a problem by deteriorating the resin in the past, that is, in the matrix resin as a precursor to form the inorganic insulating coating or This energy can be used as a heat source for converting the inorganic insulating coating-forming silicon-containing material present on the surface of the matrix resin to form the inorganic insulating coating, and can be formed from the silicon-containing material. Here, the mechanism by which the silicon-containing material is converted into the inorganic insulating coating is that the silicon-containing material constituting the silicon-containing material reacts with oxygen by partial discharge, resulting in the formation of silicon oxide and the use of an insulating member. As the reaction continues, further reaction proceeds. As a result, a substance having a very high insulating property as compared with the resin is precipitated, and the insulating property improves as the insulating member is used. In the insulating member of the present invention, as a result of the inorganic insulating coating formed on the surface of the insulating member, excellent corona resistance derived from the occurrence of partial discharge can be achieved in the insulating member.

  According to another method, the insulating member may be composed of a single resin. In that case, the matrix resin is similar to the inorganic insulating coating-forming silicon-containing material, and has a similar mechanism. A substance that can be produced, that is, an inorganic insulating substance-forming silicon-containing material is blended. Insulating members made of resin have an inorganic insulating substance-forming silicon-containing material dispersed inside them, so that excellent corona resistance derived from the occurrence of partial discharge is achieved in insulating members by the same mechanism as above. can do.

In one aspect, the present invention is an insulating member used in the presence of a partial discharge generated by application of a high voltage,
A composite insulating member comprising a main body made of a base resin and an inorganic insulating coating-forming silicon-containing material applied to at least one surface of the main body, and the silicon-containing material is partially discharged to the insulating member When the is applied, the insulating member can be converted into the inorganic insulating coating.

In another aspect, the present invention is an insulating member used in the presence of a partial discharge generated by application of a high voltage,
The insulating member is formed of a compound material in which an inorganic insulating substance-forming silicon-containing material is dispersed in a base resin, and the silicon-containing material is obtained when a partial discharge is applied to the insulating member. The insulating member is characterized in that it can be converted into an inorganic insulating coating.

  Furthermore, the present invention, in another aspect, resides in an article, for example, an electrical product, an automobile part, etc., such as an automobile ignition coil, comprising the insulating member according to the present invention as a constituent element.

  According to the present invention, as will be understood from the following detailed description, since the corona resistance of the insulating member can be dramatically improved, various articles (products) using the insulating member in part or in whole. ), For example, the service life and reliability of an automobile ignition coil can be improved. In addition, since the insulating member is made of a resin, the weight can be reduced, and a good mechanical strength and high toughness can be achieved by selecting the resin. Further, these excellent effects can be realized not only in the ignition coil but also in other articles that are used under a high voltage and have an insulating member as one member.

It is explanatory drawing which showed in cross section the 1 manufacturing method of the insulating member by this invention. It is explanatory drawing which showed another manufacturing method of the insulation member by this invention in the cross section. It is sectional drawing which showed an example of the ignition coil which can use the insulating member of this invention as one member. It is the fragmentary sectional view which showed the usage example of the insulating member of this invention in the ignition coil shown in FIG. It is a schematic diagram of the test apparatus used for the corona resistance evaluation test of an insulating member.

  Next, an embodiment for carrying out the present invention will be described with reference to FIGS.

  FIG. 1 is an explanatory view showing in section a method for manufacturing an insulating member according to the present invention. As shown in FIG. 1C, the insulating member 5 of the present invention is a composite insulating member composed of a main body 1 made of a base resin and an inorganic insulating coating 4 formed only on the upper surface of the main body 1. is there. Note that the inorganic insulating coating 4 may be formed only on the lower surface of the main body 1 as necessary, or may be formed on both the upper and lower surfaces of the main body 1. The insulating member 5 of the present invention can exert its effect particularly when used in the presence of partial discharge generated by application of a high voltage.

  According to the present invention, the inorganic insulating coating 4 is not formed by directly applying to the surface of the main body 1 but is formed through its precursor (A) or (B). . That is, the inorganic insulating coating 4 is applied to the surface of the main body 1 with the liquid inorganic insulating coating-forming silicon-containing material 2 as shown in FIG. After the sheet-like or film-like inorganic insulating coating-forming silicon-containing material 3 is laminated as shown in FIG. 2, the composite insulating member as the obtained precursor is formed by applying partial discharge. According to the present invention, the inorganic insulating coating-forming silicon-containing material 2 or 3 can be converted into the inorganic insulating coating 4 by using the energy by partial discharge that has caused the resin to deteriorate.

  In the practice of the present invention, as long as the base resin constituting the main body is an insulating resin, the material, shape, size, and the like are not limited, and the insulating resin that is normally used as an insulating member is not limited. An appropriate resin can be arbitrarily selected and used. Suitable insulating resins include, for example, general-purpose thermoplastic / thermosetting plastics such as PPS (polyphenylene sulfide) resin, PA (polyamide) resin, PBT (polybutylene terephthalate) resin, PP (polypropylene) resin, PE ( Polyethylene) resin, PET (polyethylene terephthalate) resin, PPE (polyphenylene ether) resin, PEEK (polyether ether ketone) resin, LCP (liquid crystal polymer), PEI (polyetherimide) resin, PAI (polyamideimide) resin, phenolic resin And engineering plastics such as epoxy resin and super engineering plastics. A particularly suitable base resin is excellent in heat resistance and insulation, and also in terms of physical properties and cost, and can be a PPS resin.

  The inorganic insulating coating can be formed from a liquid inorganic insulating coating-forming silicon-containing material or a sheet-like or film-like inorganic insulating coating-forming silicon-containing material, and a desired inorganic insulating coating is formed. As long as the coating-forming silicon-containing material is not limited. That is, the silicon-containing material can be basically used as long as it is a viscous liquid or sheet (film) containing silicon (Si) element in its structure. The silicon-containing material can contain an arbitrary additive for improving workability and physical properties as required. Suitable additives include, for example, a viscosity modifier for improving processability, a curing reaction catalyst (such as platinum), a colorant, and a physical property improver (such as a rubber component).

  Further describing the coating-forming silicon-containing material, a preferred silicon-containing material is an adhesive based on organopolysiloxane. In the case of this adhesive, as a result of the silicon (Si) contained therein reacting effectively with oxygen by partial discharge, a substance having a very high insulating property can be easily generated. The silicon (Si) element content in the silicon-containing material is preferably an amount that can be effectively used for the reaction as described above, usually in the range of about 5 to 95% by weight, and more preferably about 40%. It is in the range of ˜50% by weight. The silicon-containing material is more preferably a silicone adhesive. Such adhesives are also commercially available, and are readily available, for example, as product number SE1714 from Toray Dow Corning.

  As described above, the inorganic insulating coating is formed by applying a liquid inorganic insulating coating-forming silicon-containing material to the surface of the main body made of the base resin, or by forming a sheet-like or film-like inorganic insulating coating-forming silicon-containing material. Can be formed by applying partial discharge to the obtained composite insulating member as a precursor. When an inorganic insulating coating is formed by application of a liquid silicon-containing material, it can be applied by using a conventional method such as brush application, spray application, dip application, etc., and subsequently cured by leaving or heating. . The film thickness of the coating is usually in the range of about 10 to 4000 μm. In addition, when forming an inorganic insulating coating by laminating a sheet-like or film-like silicon-containing material, for example, a sheet or film of a silicon-containing material is formed in advance, and this sheet or film is, for example, under pressure. If necessary, an appropriate adhesive can be used in combination and laminated or integrated on the surface of the resin member by means of spreading, winding, heat shrinking or the like. The thickness of the sheet or film is usually in the range of about 10 to 4000 μm.

According to another method, the insulating member 5 of the present invention can be formed by a technique as shown in FIG. In the case of this embodiment, as described above with reference to FIG. 1, instead of applying a liquid, sheet-like or film-like inorganic insulating coating-forming silicon-containing material to the surface of the main body made of the base resin. As shown in FIG. 2 (A), an inorganic insulating material-forming silicon-containing material 8 capable of exhibiting the same behavior as the inorganic insulating coating-forming silicon-containing material is dispersed in the base resin 7 itself. Use compound material. The form of the silicon-containing material 8 to be dispersed is not particularly limited, but is preferably used in the form of a fine powder in order to achieve good dispersibility and the like. Moreover, the compounding quantity of the silicon-containing material 8 can be changed in a wide range. The silicon-containing material 8 is converted to the inorganic insulating substance-containing base resin 9, in other words, the insulating member 5 when partial discharge is applied thereto. As can be easily understood, in the case of this compound material, as in the case described above with reference to FIG. 1, silicon (Si) contained in the compound material effectively reacts with oxygen by partial discharge. In addition, an inorganic insulating material having a high insulating property can be easily generated in the insulating member 5.

  The insulating member of the present invention can be advantageously used as one member in various products that require excellent corona resistance, such as electrical products and automobile parts. As an example of a product in which the insulating member of the present invention can be used, an example of an automobile ignition coil will be described below with reference to FIG.

  FIG. 3 is a longitudinal sectional view showing a basic configuration of an ignition coil 100 to which the present invention can be applied. In the illustrated ignition coil 100, the housing 10 is made of a hard resin such as PBT, has a rectangular box shape having a bottom surface larger than the cross-sectional area of the plug hole 12 of the engine head 11, and is fixed to the outside of the opening of the plug hole 12. Has been. In addition, connector portions 10 a that protrude outward from the housing 10 are integrally formed on the side wall of the housing 10. The connector portion 10a serves to electrically connect an external power source (not shown) and the igniter 23. Furthermore, a cylindrical member 10 b that protrudes from the housing 10 toward the plug hole 12 is integrally formed on the bottom wall of the housing 10 that faces the engine head 11.

  As shown in the figure, a central core 13, a primary spool 14, a primary coil 15, a secondary spool 16 and a secondary coil 17 are accommodated in the housing 10, and an outer peripheral core 18 is disposed outside the housing 10. Is provided.

  The central core 13 is formed by laminating magnetic materials and has a cylindrical shape as a whole. The central core 13 is provided so that its axial direction is substantially perpendicular to the axial direction of the plug hole 12.

  The outer peripheral core 18 is formed by laminating magnetic materials, and has a box shape that opens toward the plug hole 12 as a whole. A pair of opposing side surfaces of the outer core 18 are opposed to both end surfaces of the central core 13, thereby forming a closed magnetic path that suppresses magnetic energy loss between the central core 13 and the outer core 18. ing.

  The primary spool 14 is made of a hard resin such as PP or PE, and is provided substantially concentrically with the central core 13 on the outer peripheral side of the central core 13. The primary coil 15 is formed by winding a primary winding 115 having a circular cross section around a bobbin-shaped primary spool 14. Note that the primary coil 15 is formed by winding a copper wire having a diameter of 0.3 to 0.8 mm for 100 to 230 turns.

  The secondary spool 16 is made of a hard resin such as PP or PE, and is provided substantially concentrically with the central core 13 on the outer peripheral side of the primary coil 15. The secondary coil 17 is formed by winding a secondary winding 117 having a circular cross section around a bobbin-shaped secondary spool 18. The secondary coil 17 is formed by winding a copper wire having a diameter of 30 to 100 μm, preferably 40 to 50 μm, using a winding method such as 10,000 to 20000 turns and oblique winding.

  The housing 10 is filled with a resin material 20. The resin material 20 is interposed between the secondary coil 17 and the housing 10, and electrically insulates both. The resin material 20 is also interposed between the primary coil 15 and the secondary coil 17 and electrically insulates both.

  As shown in the drawing, the seal member 24 is made of a rubber material and has a substantially cylindrical shape as a whole. The seal member 24 is interposed between the outer peripheral surface of the cylindrical member 10b, the bottom wall of the housing 10, and the upper surface of the engine head 11, and seals the opening of the plug hole 12. A high voltage terminal 22 is provided on the inner peripheral side of the cylindrical member 10 b, and the winding end portion of the self-bonding wire constituting the secondary coil 17 is electrically connected to the high voltage terminal 22 via the metal terminal 21. Has been.

  In the above configuration, when the igniter 23 having a built-in switching element cuts off the current flowing through the primary coil 15 by a signal from an engine control unit (not shown), the mutual induction between the primary and secondary coils 15 and 17 causes A high voltage of 40 kV is generated in the secondary coil 17. The high voltage generated in the secondary coil 17 in this way is guided to the spark plug 101 via the high voltage terminal 22 and the like, and spark discharge is generated at the tip of the spark plug 101.

  As described above, the housing 10 is filled with the resin material 20, and the resin material 20 includes the central core 13, the primary spool 14, the primary coil 15, the secondary spool 16, the secondary coil 17, and the outer core. 18 and the igniter 23 are sealed and insulated.

  The illustrated resin material 20 contains 75% by weight of spherical silica (not shown) as a filler in a thermosetting resin. In addition to insulating properties, the thermosetting resin has adhesiveness to the central core 13, primary spool 14, primary coil 15, secondary spool 16, secondary coil 17, outer core 18, and igniter 23, and cost saving. Therefore, it is preferable to use an epoxy resin. When the temperature is lower than the glass transition point Tg, the resin material 20 becomes a glass having no fluidity, and when the temperature is higher than the glass transition point Tg, the resin material 20 becomes a fluid rubber. In addition, although both differ in a state, a composition is the same.

  In the ignition coil 100 shown in FIG. 3, the insulating member of the present invention can be used as, for example, an annular resin part that insulates a plug hole and a high voltage portion (for example, a spring). FIG. 4 is a partial sectional view showing an example of use of the insulating member of the present invention in the ignition coil shown in FIG.

  As shown in the figure, the insulating member 5 of the present invention has a form of an annular member surrounding the spring 19 and is disposed in a space of a plug hole 12 formed inside the engine head 11. The insulating member 5 includes a main body 1 made of a base resin, and inorganic insulating coatings 4a and 4b formed on both surfaces of the main body 1. The inorganic insulating coating is formed by laminating a sheet of inorganic insulating coating-forming silicon-containing material on the main body 1 and then exposing it to partial discharge. Details of the formation of the inorganic insulating coating are as described above.

  Subsequently, the present invention will be described with reference to examples thereof. In addition, this invention is not limited by the following Example.

  In this example, in order to confirm that a highly reliable, lightweight, and tough insulating member can be manufactured at low cost, the following test is performed using the test apparatus for corona resistance evaluation shown in FIG. An evaluation test was conducted under the conditions.

  In the test apparatus shown in FIG. 5, a plate-like sample 31 is a PPS resin flat plate (100 mm × 100 mm × 1 mm), and a film-like sample 32 is laminated thereon. The film-like sample 32 was a silicone adhesive (product number: SE1714, manufactured by Toray Dow Corning) having a thickness of 0.5 mm or less. As shown in the drawing, these samples were sandwiched between a spherical upper electrode (steel ball) 34 having a diameter of 20 mm and a flat plate lower electrode (GND) 35 having a diameter of 25 mm with an interelectrode distance of 1 mm. Next, the upper electrode 34 was pressed against the sample 32, the ignition coil 33 was connected to the upper electrode 34, and a voltage of 25 kV was applied at a frequency of 100 Hz. The waveform of the ignition coil 33 was a break waveform. It was 710 hours when the voltage application was repeated and the corona destruction lifetime until the corona destruction occurred in the sample 21 was measured. Then, for comparison, when the above method was repeated with the film-like silicone adhesive sample 32 removed, the corona fracture life until the corona fracture occurred was significantly shortened to 105 hours. confirmed.

  In the example of the present invention, the corona fracture life is 710 hours, and in the comparative example, it is at most 105 hours. Therefore, according to the present invention, silicon contained in the insulating member or on the surface of the insulating member is contained in silicon. It can be seen that by applying the material, the corona resistance of the insulating member after being exposed to partial discharge can be greatly improved.

  According to the present invention, since it is possible to achieve a remarkable effect such that the corona resistance of the insulating member can be dramatically improved, the insulating member of the present invention can be used in various ways using part or all of the insulating member. The present invention can be advantageously used in the manufacture of products such as electrical products and automobile parts. An example of usable articles for automobile parts includes ignition coils, inverters, converters, motors, chargers, alternators, starters, insulators, power transistors, relays, and the like.

1 Base resin (main body)
2 Liquid Silicon-Containing Material 3 Film-like Silicon-Containing Material 4 Inorganic Insulating Coating 5 Insulating Member 7 Base Resin 8 Inorganic Insulating Substance Forming Silicon-Containing Material 9 Inorganic Insulating Substance Containing Base Resin 10 Housing 11 Engine Head 12 Plug Hole 19 Spring 31 PPS resin flat plate 32 Sample (silicone adhesive film)
33 Ignition coil 34 Upper electrode 35 Lower electrode 100 Ignition coil 101 Spark plug

Claims (9)

An insulating member used in the presence of partial discharge generated by application of high voltage,
Insulating member is an inorganic insulating material forming silicon-containing material has been formed from the dispersion allowed was compounded material within the base resin, the silicon-containing material, partial discharge is applied to the insulating member An insulating member characterized in that it can be converted into an inorganic insulating coating. The insulating member according to claim 1 , wherein the silicon-containing material is an adhesive mainly composed of organopolysiloxane. The base resin is a polyphenylene sulfide (PPS) resin insulation member according to claim 1. The insulating member according to claim 1, wherein the insulating member is a resin component that insulates the plug hole from the high voltage portion. An article comprising the insulating member according to any one of claims 1 to 4 as a constituent element. It said partial discharge occurs when using the article as an electrical product, article of claim 5. It said partial discharge occurs when using the article as automobile parts, article of claim 5. It said partial discharge occurs when using the article as an ignition coil, article of claim 5. The article is an ignition coil, and the ignition coil includes the insulating member disposed in a space of a plug hole formed inside the engine head, and surrounds a spring of the ignition coil with the insulating member. The article according to claim 5.

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