JP4045632B2 - Ignition coil - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ignition coil, and more particularly to an ignition coil in which an inner core, an inner winding body and an outer winding body are concentrically housed in a cylindrical case and filled with an insulating resin.
[0002]
[Prior art]
As a conventional ignition coil, as shown in FIG. 16, an inner core 102 is disposed at the center of the case 101, and the primary coil 103 and the secondary coil 104 are concentrically arranged so as to surround the outer periphery of the inner core 102. An arrangement is known (for example, “ignition device for internal combustion engine” described in JP-A-8-293418 and JP-A-9-167709).
[0003]
In addition, since a high voltage for ignition is generated in such an ignition coil 100, the insulating layer 105 is formed by filling the case 101 with an insulating resin and curing, and the insulating layer 105 provides insulation between the members. We are trying to ensure sex.
[0004]
[Problems to be solved by the invention]
However, in the ignition coil, each member disposed in the case 101 is made of a different material such as metal or resin, and since these individual thermal expansion coefficients are different, the ignition coil is different depending on the ambient temperature. When the temperature is lowered, thermal stress due to the thermal shrinkage difference may be generated in the insulating layer 105, and a minute crack, that is, a partial defect may be generated in the layer 105. In addition to the thermal stress caused by the thermal shrinkage difference, such a partial defect is similarly generated by the residual stress generated when the insulating resin is cured and contracted after the case 101 is filled with the insulating resin. .
[0005]
When such a partial defect occurs in the insulating layer 105 between the primary coil 103 and the secondary coil 104, the dielectric constant of the portion where the defect has occurred increases, and the potential gradient in the same portion becomes local. To increase. As a result, the defective portion may be burned out by discharge, which may cause a decrease in durability and reliability in the ignition coil.
[0006]
In addition, cracks may also occur in the insulating layer 105 located on the outer peripheral side of the secondary coil 104 due to the thermal stress or residual stress, and the crack gradually develops to the inner side of the ignition coil 100. Similarly, when a partial defect occurs between the two coils 104 and 105, the durability and reliability of the ignition coil may be similarly reduced.
[0007]
The present invention has been made in view of such circumstances, and its purpose is to suppress the occurrence of partial defects in the resin due to thermal shrinkage or thermosetting shrinkage of the insulating resin, and to improve durability and reliability of the ignition coil. It is to improve the performance.
[0008]
[Means for Solving the Problems]
  Less than,To achieve the above purposeThis means and its action will be described.
Claim 1In the invention, each winding is wound in layersThe inner winding body and the outer winding bodyIn caseHoused inThe innermost layer of the outer winding body and the inner winding body;Between andAboveOuter winding bodyBetween the outermost layer and the caseIn an ignition coil in which an insulating resin is filled and cured,AboveOutside winding bodyOutermost layerEquipped with a film to coatAnd restricting the penetration of the insulating resin between the layers of the outer winding body through the cooperation of the innermost layer wound in alignment with the outer winding body and the film, and when the insulating resin contracts The gist of the invention is to allow a radial separation between the innermost layer and the outermost layer of the outer winding body.
[0009]
  According to the said structure, the outer peripheral part of an outer side winding body is coat | covered with the film.At the same time, the innermost layer of the outer winding body is formed as an aligned winding layer that restricts the penetration of the insulating resin.For,With the cooperation of these films and the innermost layer,It becomes difficult for the insulating resin filled in the case to enter the gaps between the layers of the outer winding body. For this reason, each winding layer of the outer winding body is not bonded by the insulating resin, or even if bonded, it becomes partial, and the gap between the winding layers of the outer winding body can be enlarged. And when this clearance gap expands, the thermal shrinkage and hardening shrinkage of insulating resin are absorbed, and the thermal stress and residual stress which generate | occur | produce in insulating resin are relieved.
[0010]
  Claim 2The invention ofThe ignition coil according to claim 1, whereinSaidAt least one side of the film contacts the same sideAboveOuter winding orBetween the outermost layer of the outer winding body and the casePeelability against insulating resinIts gist is to have it.
[0011]
  According to the above configuration, one surface of the peelable film and the outer winding body orBetween the outermost layer of the outer winding body and the caseThe insulating resin does not adhere and there is an expandable gap between the film and the outer winding body or the insulating resin. Therefore, thermal contraction and curing shrinkage generated in the insulating resin due to expansion of the gap are absorbed. For this reason, even if the insulating resin penetrates into the gaps between the winding layers of the outer winding body and the winding layers are bonded by the insulating resin, the thermal stress and residual stress generated in the insulating resin are reliably reduced. Is done.
[0012]
  Claim 3In the invention, each winding is wound in layersThe inner winding body and the outer winding bodyIn caseHoused inThe outer winding and the inner winding body;Between andAboveOuter winding bodyBetween the case andIn an ignition coil that is filled and cured with insulating resin, at leastPiecesurfaceSaidOuter winding body andAboveA film that is peelable from insulating resinAboveOutside winding bodyInterlayer onlyIntervening inThe gist of this is
[0013]
  According to the above configuration, one surface of the peelable film does not adhere to the outer winding body and does not adhere to the insulating resin that has entered the outer winding body. Therefore, since thermal shrinkage and curing shrinkage that occur in the insulating resin are absorbed by the expansion of the gap between the film and the outer winding body or the insulating resin, the thermal stress and residual stress of the resin are reliably reduced. Become so. In addition, the film is between the outer windings.onlyTherefore, both the inner peripheral portion and the outer peripheral portion of the outer winding body are covered with the insulating resin.
[0014]
  Claim 4In the invention, each winding is wound in layersThe inner winding body and the outer winding bodyIn caseHoused inAn inner resin, which is an insulating resin, is provided between the outer winding body and the inner winding body, and an outer resin, which is an insulating resin, is provided between the outer winding body and the case.In a filled and cured ignition coil, at leastPiecesurfaceButTouch the same surfaceAboveOuter winding orInsideFilm with releasability from resinBy providing a boundary portion between the outer winding body and the inner resin.Covers the inner periphery of the outer winding bodyIt is the gist of that.
[0015]
  According to the above configuration, one surface of the peelable film and the outer winding body orInsideThe resin will not adhere. Therefore, the heat shrinkage and curing shrinkage that occur in the insulating resin are the film and outer winding body orInsideSince the gap between the resin and the resin is increased,InsulationThe thermal stress and residual stress of the resin are reduced.
[0016]
  Claim 5In the invention, each winding is wound in layersAn inner winding body and an outer winding bodyWhenTubular outer coreWhenButIn caseHoused inThe outer winding body and the inner winding body are disposed inside the outer core, and an inner resin, which is an insulating resin, is disposed between the outer winding body and the inner winding body. Between the winding body and the outer core, there is an outer resin that is an insulating resin, respectively.In a filled and cured ignition coil, at leastPiecesurfaceButTouch the same surfaceAboveOuter core orOuter resinFilm with peelabilityIs provided at the boundary between the outer core and the outer resin.Covers the inner periphery of the outer coreIt is the gist of that.
[0017]
  According to the above configuration, one surface of the peelable film and the outer core orOutsideThe resin will not adhere and the film and outer core orOutsideAn expandable gap exists between the resin and the resin. Therefore, since the thermal contraction and curing shrinkage generated in the insulating resin are absorbed by the expansion of the gap, the thermal stress and residual stress of the resin are reduced.
[0018]
  Claim 6In the invention, each winding is wound in layersThe inner winding body and the outer winding bodyIn caseHoused inAn inner resin, which is an insulating resin, is provided between the outer winding body and the inner winding body, and an outer resin, which is an insulating resin, is provided between the outer winding body and the case.In an ignition coil that is filled and cured,InsideResin andOutsideresinOneAt least insidePiecesurfaceButFilm with releasability from insulating resinArrangePlaceIt is the gist of that.
[0019]
  According to the above configuration, one surface of the peelable film and the insulating resin do not adhere, and the filmAndThere is an expandable gap between the edge resin. Therefore, since the thermal contraction and curing shrinkage generated in the insulating resin are absorbed by the expansion of the gap, the thermal stress and residual stress of the resin are reduced.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. This ignition coil is applied to an engine that employs a so-called DLI ignition system (Distributor Less Ignition system) that does not require a distributor.
[0021]
As shown in FIG. 1, the ignition coil 10 includes a case 11, an inner core 12, a secondary coil 13, a primary coil 14, and an outer core 15 accommodated in the case 11. The case 11 includes an igniter 20 for intermittently controlling the primary current flowing through the primary coil 14.
[0022]
As described above, the gaps between the members housed in the case 11 are sealed with the insulating layer 16. This insulating layer 16 is formed by filling a case 11 with a liquid epoxy resin and heating and curing at a predetermined temperature. The insulating layer 16 ensures insulation between the members in the case 11.
[0023]
The case 11 is formed in a substantially cylindrical shape by a resin material such as PBT (polybutylene terephthalate) resin. A connecting portion 11a to which a harness (not shown) from an engine control device (none of which is not shown) is connected to an upper end portion of the case 11 and an ignition coil 10 are bolted to a cylinder head (not shown) of the engine. A mounting portion 11b is integrally formed, and a cylindrical member 18 made of a resin material such as PBT resin is fitted into the lower end portion thereof. A metal high-pressure member 21 is fixed inside the cylindrical member 18, and an upper end portion of a spring 22 electrically connected to a spark plug (not shown) is fixed to the high-pressure member 21. A cylindrical rubber boot 23 made of silicon rubber is fitted on the lower end portion of the cylindrical member 18.
[0024]
The inner core 12 is formed in a cylindrical shape by laminating a plurality of silicon steel plates, and is disposed in the center of the case 11 so as to extend in the vertical direction. Magnets 25 and 26 are fixed to upper and lower ends of the inner core 12, and the magnets 25 and 26 and the inner core 12 are entirely covered with a rubber layer 27.
[0025]
A secondary bobbin 30 having a substantially cylindrical shape is externally fitted to the magnets 25 and 26 and the inner core 12 covered with the rubber layer 27 as described above. The secondary bobbin 30 is made of PPE (polyphenylene ether) resin, which is a thermoplastic resin, and a plurality of ribs 31 are formed on the outer periphery thereof at predetermined intervals in the axial direction. Between these ribs 31, a secondary winding 32 made of an enameled wire having a wire diameter of 0.03 to 0.1 mm is laminated and wound. A terminal 33 that contacts the high-voltage member 21 is fixed to the lower end of the secondary bobbin 30, and a high-voltage side terminal (not shown) of the secondary winding 32 is connected to the terminal 33. The secondary winding 32 and the secondary bobbin 30 constitute a secondary coil 13 that generates a high voltage for ignition.
[0026]
A cylindrical primary coil 14 is fitted on the outer peripheral side of the secondary coil 13 at a predetermined interval in the radial direction. Unlike the secondary coil 13, the primary coil 14 is a bobbin-less coil having no bobbin, and a primary winding 34 made of enameled wire having a wire diameter of 0.3 to 1.0 mm is formed in a cylindrical shape. Thus, it is comprised by the winding body 35 wound in two layers, and a pair of sleeves 37 and 38 arrange | positioned at the both ends of the winding body 35. As shown in FIG. Each of the sleeves 37 and 38 has a function of holding the winding body 35 in a predetermined shape, and flanges 37a and 38a with which the upper and lower ends of the winding body 35 come into contact are formed on the outer periphery thereof.
[0027]
Further, as shown in FIG. 2, the inner peripheral surface of the winding body 35 is substantially entirely covered with a belt-like film 40. An insulating layer 16 is formed between the film 40 and the secondary coil 13.
[0028]
As shown in FIG. 5, the film 40 includes a base layer 41 made of glass cloth, a release layer 42 laminated on the inner peripheral surface of the base layer 41, and an adhesive layer 43 laminated on the outer peripheral surface of the base layer 41. It has a three-layer structure. The release layer 42 is formed by applying a known silicon material (silicon oil) as a mold release material to one surface of the base layer 41, and is in contact with the insulating layer 16. Since this silicon material has a weak affinity for the epoxy resin forming the insulating layer 16, the adhesive force between the peeling layer 42 and the insulating layer 16 is extremely weak. The pressure-sensitive adhesive layer 43 is formed of a well-known silicon-based pressure-sensitive adhesive, and is in contact with an inner peripheral winding layer (hereinafter referred to as “inner peripheral layer”) 35 a of the winding body 35.
[0029]
A cylindrical outer core 15 is fitted on the outer peripheral side of the winding body 35 at a predetermined interval in the radial direction (left-right direction in FIG. 2). The outer core 15 has a double tube structure in which a cylindrical tube made of a silicon steel plate is superposed, and an outer peripheral surface thereof is in contact with an inner peripheral surface of the case 11. An insulating layer 16 is also formed by filling the outer core 15 and a winding layer 35b (hereinafter abbreviated as “outer peripheral layer”) 35b on the outer peripheral side of the winding body 35 with an epoxy resin. The inner peripheral surface of the outer core 15 is in contact with the insulating layer 16.
[0030]
The ignition coil 10 configured as described above is inserted into a plug hole formed in an engine cylinder head (not shown), and is bolted to the cylinder head at the mounting portion 11b. When the ignition coil 10 is fixed to the cylinder head in this way, the spring 22 comes into contact with the upper terminal (not shown) of the spark plug, and the outer periphery of the upper end of the spark plug is covered with the rubber boot 23. The ignition high voltage generated in the secondary coil 13 is supplied to the spark plug via the high-pressure member 21 and the spring 22.
[0031]
Next, a procedure for forming the winding body 35 described above will be described with reference to FIG.
First, as shown in FIG. 3A, the sleeves 37 and 38 are connected to the rotating shaft C1 of the winding machine so that the distance between the flanges 37a and 38a is equal to the length of the winding body 35 in the axial direction. On the other hand, it is fixed so that it can rotate integrally. Next, as shown in FIG. 3B, the film 40 is spirally wound around the rotation axis C1 between the flanges 37a and 38a while rotating the rotation axis C1. At this time, the adhesive layer 43 of the film 40 is made to be the outer peripheral surface. Further, as shown in FIG. 3 (c), the primary winding 34 is aligned between the flanges 37a and 38a on the outer peripheral surface of the film 40, that is, on the adhesive layer 43, that is, the wires are in close contact with each other. In this state, the winding body 35 is formed by winding two layers.
[0032]
As described above, in the ignition coil 10 according to the present embodiment, the inner peripheral surface of the winding body 35 is covered with the film 40, and the film 40 is peeled from the insulating layer 16 located between the coils 13 and 14. Layer 42 is in contact. As described above, since the silicon material forming the peeling layer 42 has a weak affinity for the epoxy resin forming the insulating layer 16, the adhesive force between the film 40 and the insulating layer 16 is extremely weak.
[0033]
Therefore, heat shrinkage or curing shrinkage occurs in the insulating layer 16 located between the coils 13 and 14 or between the primary coil 14 and the outer core 15, and both of the contact portions of the insulating layer 16 and the film 40 are in contact with each other. When a stress is applied to separate the two, a gap G is formed between the two 16 and 40 as shown in FIG. By forming this gap G, the thermal stress and residual stress of the insulating layer 16 are released and reliably reduced.
[0034]
Although the gap G is the same as a crack in that a portion having a large dielectric constant is formed, the gap G is different in that the gap G is formed substantially uniformly throughout the axial direction and the circumferential direction of the ignition coil 10. That is, since the potential gradient does not increase locally like a crack, the gap G cannot be a partial defect that causes partial discharge.
[0035]
As described above, according to the present embodiment, since the thermal stress and residual stress of the insulating layer 16 are released and reliably reduced by the formation of the gap G, the occurrence of partial defects in the same layer 16 is reliably suppressed, and the ignition coil 10 durability and reliability can be improved.
[0036]
Further, since the ignition coil 10 is housed in the plug hole, the primary coil 14 having a bobbinless structure is employed to reduce the diameter. In this way, the primary coil 14 having the bobbinless structure is used. In the case of adopting the above, there is a concern that the primary winding 34 may be collapsed and it becomes difficult to maintain the shape of the winding body 35 in a predetermined shape.
[0037]
In this regard, in this embodiment, the film 40 having the adhesive layer 43 is used, and the primary winding 34 is wound on the adhesive layer 43. Accordingly, the collapse of the primary winding 34 is suppressed by the adhesive force in the adhesive layer 43, and the shape of the winding body 35 and the winding density thereof can be stabilized.
[0038]
In the present embodiment, an adhesive layer 43 made of a silicon-based adhesive is laminated on the outer peripheral surface of the film 40. For this reason, it is possible to absorb heat shrinkage and curing shrinkage generated in the insulating layer 16 by elastic deformation of the adhesive layer 43. Accordingly, since the thermal stress and residual stress of the insulating layer 16 are reduced, the occurrence of partial defects in the same layer 16 can be reliably suppressed.
[0039]
Furthermore, in this embodiment, after winding the film 40 around the rotating shaft C1 of the winding machine, the winding body 35 is manufactured by winding the primary winding 34 on the film 40. Accordingly, when the winding body 35 is extracted from the rotating shaft C1, the inner peripheral surface thereof is protected by the film 40, so that the rotating shaft C1 and the primary winding 34 rub against each other. Thus, the reliability of the ignition coil 10 can be further improved.
[0040]
In the present embodiment, since the release layer 42 and the adhesive layer 43 are formed of a silicon-based material having excellent heat resistance, the layers 42 and 43 are hardly altered by heat. Therefore, even when the ignition coil 10 is used at a high temperature for a long time, the peelability or tackiness in the respective layers 42 and 43 is maintained, and the action based on the above-described peelability and tackiness can be reliably achieved. it can.
[0041]
Further, the ignition coil 10 accommodated in the plug hole as in the present embodiment is limited in its shape and the potential gradient in the case 11 is extremely large. In addition, reliability tends to be greatly reduced. In this respect, the configuration according to the present embodiment can suppress the occurrence of partial defects in the insulating layer 16 due to thermal stress or residual stress, and thus is suitable for the ignition coil having the above tendency.
[0042]
[Second Embodiment]
Next, the second embodiment will be described with a focus on differences from the first embodiment. In addition, about the structure similar to the said 1st Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol.
[0043]
FIG. 6 shows an enlarged cross section of the ignition coil 10 in the present embodiment. As shown in the figure, the ignition coil 10 is different from the first embodiment in the arrangement position of the film 40 in the case 11 and the structure of the film 40. In other words, in this embodiment, the outer peripheral surface of the winding body 35 is substantially entirely covered with the film 40, and the insulating layer 16 is formed between the film 40 and the outer core 15 by being filled with epoxy resin. ing.
[0044]
The film 40 includes a base layer 41 and an adhesive layer 43 laminated on the inner peripheral surface of the base layer 41, and has a two-layer structure in which the release layer 42 is omitted. The base layer 41 is made of a resin material such as polyphenylene sulfide (PPS) resin, polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN) resin, and is in contact with the insulating layer 16 located on the inner peripheral side of the outer core 15. Similar to the first embodiment, the adhesive layer 43 is made of a silicon adhesive and is in contact with the outer peripheral portion of the outer peripheral layer 35a.
[0045]
In the present embodiment, the primary winding 34 is wound in two layers by a winding machine to form the winding body 35, and then the outer circumferential layer 35b of the winding body 35 is formed in the same manner as in the first embodiment. The belt-like film 40 is wound.
[0046]
In the ignition coil 10 having the above-described configuration, the outer peripheral surface of the winding body 35 is covered with the film 40, so that the liquid epoxy resin filled in the case 11 is the outer periphery of the winding body 35. It does not enter between the winding layers 35a and 35b from the side. Further, since the primary winding 34 is aligned and wound to form the winding body 35, epoxy resin may enter between the winding layers 35a and 35b of the winding body 35 from the inner peripheral side thereof. Almost no. As a result, the epoxy resin hardly penetrates between the winding layers 35a and 35b of the winding body 35, and the inner peripheral layer 35a and the outer peripheral layer 35b are not bonded by the epoxy resin or are partially bonded. It becomes. For this reason, the adhesive force between the winding layers 35a and 35b of the winding body 35 is extremely weak.
[0047]
Therefore, heat shrinkage or hardening shrinkage occurs in the insulating layer 16 located between the coils 13 and 14 or between the film 40 and the outer core 15, and tries to separate the inner peripheral layer 35a and the outer peripheral layer 35b of the winding body 35. When the stress is applied, a gap G is formed between the winding layers 35a and 35b as shown in FIG. And by forming such a gap G, the thermal stress and residual stress of the insulating layer 16 are released and reduced. For this reason, also in this embodiment, generation | occurrence | production of the partial defect in the insulating layer 16 can be suppressed, and durability and reliability of the ignition coil 10 can be improved.
[0048]
In the present embodiment, the outer periphery of the winding body 35 is covered with the film 40, and the adhesive layer 43 of the film 40 is brought into contact with the outer peripheral layer 35 b of the winding body 35. Therefore, the collapse of the primary winding 34 is suppressed by the adhesive force in the adhesive layer 43, and the shape of the winding body 35 can be stabilized.
[0049]
[Third Embodiment]
Next, the third embodiment will be described focusing on differences from the second embodiment. In addition, about the structure similar to the said 2nd Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol.
[0050]
FIG. 8 shows an enlarged cross section of the ignition coil 10 in the present embodiment. As shown in the figure, the ignition coil 10 is different from the second embodiment in the structure of the film 40 that covers the outer periphery of the winding body 35. That is, in the present embodiment, a film 40 having a three-layer structure in which a release layer 42 is laminated on the outer peripheral surface of a base layer 41 made of a resin material is used, and the release layer 42 of the film 40 is formed in the outer core 15. It is made to contact with the insulating layer 16 located on the circumferential side. Similar to the second embodiment, the release layer 42 is formed by applying silicon oil to one surface of the base layer 41.
[0051]
According to the present embodiment configured as described above, the peeling layer 42 in contact with the insulating layer 16 has a weak affinity for the insulating layer 16, and thus the adhesive force between the film 40 and the insulating layer 16 is extremely weak. It will be a thing.
[0052]
Therefore, heat shrinkage or curing shrinkage occurs in the insulating layer 16 located between the coils 13 and 14 or between the film 40 and the outer core 15, and the both members 16 and 40 are separated from the contact portion between the insulating layer 16 and the film 40. When the intended stress is applied, a gap G is formed between the two 16 and 40 as shown in FIG. As a result, if an epoxy resin enters between the inner peripheral layer 35a and the outer peripheral layer 35b of the winding body 35 and the both layers 35a and 35b are bonded by the resin, as described in the second embodiment. Even when it is difficult to form the gap G between the two layers 35a and 35b, the gap G is formed between the film 40 and the insulating layer 16 as described above. The resulting thermal and residual stresses are released and reliably reduced. Further, if a gap is also formed between the inner peripheral layer 35a and the outer peripheral layer 35b of the winding body 35, the thermal stress and the like can be further reduced. For this reason, according to this embodiment, generation | occurrence | production of the partial defect in the insulating layer 16 can be suppressed more reliably, and durability and reliability of the ignition coil 10 can be improved.
[0053]
[Fourth Embodiment]
Next, the fourth embodiment will be described focusing on the differences from the first embodiment. In addition, about the structure similar to the said 1st Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol.
[0054]
FIG. 10 shows an enlarged cross section of the ignition coil 10 in this embodiment. As shown in the figure, the ignition coil 10 is different from the first embodiment in the arrangement position of the film 40 in the case 11. That is, in this embodiment, the film 40 is interposed between the inner peripheral layer 35a and the outer peripheral layer 35b of the winding body 35 over the entire periphery. Accordingly, the inner peripheral surface of the inner peripheral layer 35 a and the outer peripheral surface of the outer peripheral layer 35 b are both covered with the insulating layer 16.
[0055]
As in the first embodiment, the film 40 includes a base layer 41 made of glass cloth, a peeling layer 42 laminated on the inner peripheral surface of the base layer 41, and an adhesive layer 43 laminated on the outer peripheral surface of the base layer 41. Has a three-layer structure. The release layer 42 is in contact with the outer peripheral surface of the inner peripheral layer 35a, and the adhesive layer 43 is in contact with the inner peripheral surface of the outer peripheral layer 35b.
[0056]
Further, when forming the winding body 35 in the present embodiment, first, the primary winding 34 is wound only one layer around the rotating shaft C1 (shown in FIG. 3) of the winding machine to The peripheral layer 35a is formed. Then, a belt-like film 40 is wound around the outer periphery of the inner peripheral layer 35a as in the first embodiment. At this time, the adhesive layer 43 of the film 40 is made to be the outer peripheral surface. Thereafter, the primary winding 34 is further wound on the outer peripheral surface of the film 40, that is, on the adhesive layer 43 to form the outer peripheral layer 35 b of the winding body 35.
[0057]
Thus, in this embodiment, since the film 40 is interposed between the winding layers 35a and 35b of the winding body 35 and the release layer 42 is brought into contact with the inner peripheral layer 35a of the winding body 35, the film 40 and the inner peripheral layer 35a are not bonded. Even if the epoxy resin enters from the inner periphery of the winding body 35 to the space between the winding layers 35a and 35b, the resin comes into contact with the release layer 42 of the film 40. The resin and the film 40 are not bonded.
[0058]
Therefore, heat shrinkage or hardening shrinkage occurs in the insulating layer 16 located between the coils 13 and 14 or between the primary coil 14 and the outer core 15, and the inner peripheral layer 35a and the outer peripheral layer 35b of the winding body 35 are formed. When the stress to be separated acts, a gap G is formed between the film 40 and the inner peripheral layer 35a of the winding body 35 as shown in FIG. And by forming such a gap G, the thermal stress and residual stress of the insulating layer 16 are released and reduced. As a result, also in this embodiment, it is possible to suppress the occurrence of partial defects in the insulating layer 16 and improve the durability and reliability of the ignition coil 10.
[0059]
Further, in the present embodiment, the inner peripheral surface and the outer peripheral surface of the winding body 35 are not covered with the film 40, but the film 40 is interposed between the winding layers 35a and 35b of the winding body 35. The inner peripheral surface of the inner peripheral layer 35 a and the outer peripheral surface of the outer peripheral layer 35 b are both covered with the insulating layer 16. Therefore, the mechanical strength of the winding body 35 can be substantially increased, and the primary winding 34 can be prevented from being collapsed, and the shape of the winding body 35 can be stably maintained in the case 11. it can.
[0060]
In this embodiment, since the primary winding 34 is wound on the adhesive layer 43 of the film 40 to form the outer peripheral layer 35b of the winding body 35, the adhesive layer is the same as in the first embodiment. The collapse of the primary winding 34 is suppressed by the adhesive force at 43, so that the shape of the winding body 35 and the winding density thereof can be stabilized.
[0061]
[Fifth Embodiment]
Next, the fifth embodiment will be described focusing on the differences from the first embodiment. In addition, about the structure similar to the said 1st Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol.
[0062]
FIG. 12 shows an enlarged cross section of the ignition coil 10 in the present embodiment. As shown in the figure, the ignition coil 10 is different from the first embodiment in the arrangement position of the film 40 in the case 11 and the structure of the film 40. That is, in this embodiment, the inner peripheral surface of the outer core 15 is substantially entirely covered with the film 40, and the insulating layer 16 is formed by filling the film 40 and the winding body 35 with epoxy resin. Has been.
[0063]
The film 40 includes a base layer 41 and a release layer 42 laminated on the outer peripheral surface of the base layer 41, and has a two-layer structure in which the adhesive layer 43 is omitted. Further, unlike the first embodiment, the film 40 formed in a cylindrical shape is fitted into the outer core 15 so that the peeling layer 42 of the film 40 is brought into contact with the inner peripheral surface of the core 15. The base layer 41 is formed of a resin material such as PPS resin, PET resin, PEN resin, or the like having a rigidity higher than that of the glass cloth in consideration of shape stability when formed into a cylindrical shape as described above, and the outer periphery of the primary coil 14. It is in contact with the insulating layer 16 located on the side. The release layer 42 is formed by applying silicon oil to one surface of the base layer 41 as in the first embodiment.
[0064]
As described above, in this embodiment, the inner peripheral surface of the outer core 15 is covered with the film 40, and the peeling layer 42 of the film 40 is brought into contact with the inner peripheral surface of the outer core 15.
[0065]
Therefore, when heat shrinkage or hardening shrinkage occurs in the insulating layer 16 located between both the coils 13 and 14 or between the primary coil 14 and the outer core 15, and a stress acting to separate the outer core 15 and the film 40 acts, As shown in FIG. 13, a gap G is formed between the both 15 and 40. By forming such a gap G, the thermal stress and residual stress of the insulating layer 16 are released and reliably reduced. As a result, also in this embodiment, it is possible to reliably suppress the occurrence of partial defects in the insulating layer 16 and improve the durability and reliability of the ignition coil 10.
[0066]
In particular, since the outer core 15 made of an iron-based material has an extremely large elastic coefficient and is difficult to be deformed, excessive thermal stress and residual stress tend to be generated in the insulating layer 16 near the outer core 15. According to the present embodiment, since the film 40 is disposed so as to be in contact with the inner peripheral surface of the outer core 15, the thermal stress and residual stress of the insulating layer 16 that tends to be excessive as described above are reliably reduced. Therefore, the occurrence of partial defects in the same layer 16 can be more reliably suppressed.
[0067]
[Sixth Embodiment]
Next, the sixth embodiment will be described focusing on differences from the first embodiment. In addition, about the structure similar to the said 1st Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol.
[0068]
FIG. 14 shows an enlarged cross section of the ignition coil 10 in the present embodiment. As shown in the figure, the ignition coil 10 is different from the first embodiment in the arrangement position of the film 40 in the case 11 and the structure of the film 40. In other words, in the present embodiment, the cylindrical film 40 is disposed concentrically with the coils 13 and 14 in the insulating layer 16 located between the secondary coil 13 and the primary coil 14.
[0069]
The film 40 includes a base layer 41 and a release layer 42 laminated on the inner peripheral surface of the base layer 41, and has a two-layer structure in which the adhesive layer 43 is omitted. After the secondary coil 13 and the primary coil 14 are accommodated in the case 11, the film 40 is inserted into the gap between the coils 13 and 14. The base layer 41 of the film 40 is formed of a resin material such as PPS resin, PET resin, or PEN resin having rigidity higher than that of the glass cloth in consideration of shape stability, and is an insulating layer positioned between the coils 13 and 14. 16 is in contact. The release layer 42 is formed by applying silicon oil to one surface of the base layer 41 as in the first embodiment, and like the base layer 41, the insulating layer 16 located between the coils 13 and 14 is formed. Touching.
[0070]
As described above, in the ignition coil 10 according to the present embodiment, the film 40 is disposed inside the insulating layer 16 positioned between the primary coil 14 and the secondary coil 13, and the inner and outer peripheral surfaces of the film 40 are changed anyway. Is also brought into contact with the insulating layer 16.
[0071]
Therefore, when thermal shrinkage or curing shrinkage occurs in the insulating layer 16 located between the coils 13 and 14 or between the primary coil 14 and the outer core 15, the film 40 and the insulating layer 16 are separated as shown in FIG. A gap G is formed between them. By forming such a gap G, the thermal stress and residual stress of the insulating layer 16 are released and reliably reduced. As a result, also in this embodiment, it is possible to reliably suppress the occurrence of partial defects in the insulating layer 16 and improve the durability and reliability of the ignition coil 10.
[0072]
The embodiment described above can be implemented by changing the configuration as follows. -In the said 1st and 4th embodiment, you may make it comprise the film 40 by the base layer 41 and the adhesion layer 43 by abbreviate | omitting the peeling layer 42. FIG. Thus, even if the peeling layer 42 is omitted, the glass cloth forming the base layer 41 has a weak affinity for enameled wire or epoxy resin, so that the adhesive force between the film 40 and the insulating layer 16 can be made extremely weak. Therefore, the thermal stress and residual stress of the insulating layer 16 can be reduced by the gap formed between the film 40 and the insulating layer 16 or the inner peripheral layer 35a, and the manufacturing cost can be reduced by omitting the release layer 42. Can be reduced.
[0073]
In the first embodiment, the release layer 42 laminated on the inner peripheral surface of the film 40 is brought into contact with the insulating layer 16, but the adhesive layer 43 is omitted and the same layer 43 is formed. A configuration may be adopted in which a release layer 42 is laminated on the outer peripheral surface of the film 40, and this release layer 42 is brought into contact with the inner peripheral layer 35 a of the winding body 35. According to such a configuration, the peeling layer 42 made of a silicon material has a weak affinity for the enameled wire of the winding body 35, so that the adhesive force between the film 40 and the winding body 35 is extremely weak. Therefore, when heat shrinkage or curing shrinkage occurs in the insulating layer 16, a gap is formed between the film 40 and the winding body 35, and the formation of this gap releases the thermal stress and residual stress of the insulating layer 16. Thus, the occurrence of partial defects in the same layer 16 can be reliably suppressed.
[0074]
In the first and fourth embodiments, the base layer 41 of the film 40 is formed of glass cloth. However, the base layer 41 may be formed of a resin material such as PPS resin, PET resin, or PEN resin. Good.
[0075]
In the second, third, fifth, and sixth embodiments, the base layer 41 of the film 40 is formed of a resin material such as PPS resin, PET resin, or PEN resin. For example, as in the first embodiment, the base layer 41 can also be formed of glass cloth. In the third, fifth, and sixth embodiments, when the base layer 41 is formed of glass cloth, the glass cloth has a low affinity for the primary winding 34 and epoxy resin. It can be omitted.
[0076]
In the third embodiment, the adhesive layer 43 laminated on the inner peripheral surface of the base layer 41 is omitted, and the release layer 42 is laminated instead of the same layer 43, and the release layer 42 is used as the outer peripheral layer 35 b of the winding body 35. You may make it contact.
[0077]
In the third, fifth, and sixth embodiments, in particular, in the configuration in which the base layer 41 is formed of a PPS resin, the PPS resin has a weak affinity for an epoxy resin, like a glass cloth. It is also possible to omit the layer 42.
[0078]
In the first to third embodiments, the release layer 42 is formed of a silicon material. However, the release layer 42 may be formed by coating a fluororesin, for example. Further, even if the peeling layer 42 is not separately formed, for example, if the film 40 is formed by a resin material to which a silicon material is added or a glass cloth impregnated with the silicon material, the film 40 having the peeling layer 42 is substantially omitted. Equivalent effects can be achieved.
[0079]
In the fourth embodiment, the arrangement positions of the release layer 42 and the adhesive layer 43 are reversed so that the release layer 42 is laminated on the outer peripheral surface of the base layer 41 and the adhesive layer 43 is laminated on the inner peripheral surface of the base layer 41. It may be.
[0080]
In the fifth embodiment, the release layer 42 is stacked on the outer peripheral surface of the base layer 41. However, the release layer 42 may be stacked on the inner peripheral surface of the base layer 41.
In the sixth embodiment, the release layer 42 is stacked on the inner peripheral surface of the base layer 41, but the release layer 42 may be stacked on the outer peripheral surface of the base layer 41. Further, the film 40 may be disposed inside the insulating layer 16 located on the outer peripheral side of the primary coil 14. Further, a release layer made of a silicon material may be formed on the inner peripheral surface of the outer core 15.
[0081]
In the second to fourth embodiments, the adhesive layer 43 may be omitted. In each of the above embodiments, the primary winding 34 is wound in two layers to form the winding body 35. However, the winding body 35 may have three or more layers.
[0082]
In each of the above embodiments, the film 40 in which the release layer 42 is laminated on both surfaces of the base layer 41 can also be employed.
In each of the above embodiments, the secondary coil 13 is arranged on the inner peripheral side and the primary coil 14 is arranged on the outer peripheral side in the case 11, but the arrangement positions of the coils 13 and 14 are reversed. May be.
[0083]
In each of the above embodiments, the igniter 20 is built in the case 11 of the ignition coil 10, but the igniter 20 may be provided outside the ignition coil 10.
[0084]
In each of the ignition coils in each of the above embodiments, the primary coil 14 has a bobbin-less structure, but the primary coil 14 may have a bobbin.
In the first to fourth and sixth embodiments, the outer core 15 may be fitted outside the case 11 without being accommodated in the case 11.
[0085]
In each of the above embodiments, the present invention is applied to the ignition coil 10 accommodated in the plug hole. However, the ignition coil 10 is not accommodated in the plug hole and disposed on the cylinder head, for example. The present invention can also be applied to.
[0086]
The technical idea grasped from each of the above embodiments will be described below together with the effects thereof.
(1) The ignition coil according to any one of claims 1 to 4, wherein the outer winding body has a bobbin-less structure without a bobbin, and the film has an adhesive layer on a surface in contact with the outer winding body. To do.
[0087]
According to the above configuration, the outer winding body can be prevented from being collapsed by the adhesive force of the adhesive layer, and the shape of the outer winding body can be stabilized.
(2) In the ignition coil described in (1) above, the adhesive layer is made of a silicon-based material.
[0088]
According to the above configuration, since the silicon-based material is excellent in heat resistance, deterioration of the adhesive layer due to heat is suppressed, and even when the ignition coil is used at a high temperature for a long time, the adhesiveness in the same layer is maintained. Can do.
[0089]
(3) In the ignition coil described in (1) above, the adhesive layer is formed of an elastic material.
According to the said structure, the thermal stress and residual stress which generate | occur | produce in insulating resin by the elastic deformation in an adhesion layer can be relieved.
[0090]
(4) The ignition coil according to any one of claims 2 to 6, wherein the film has a release layer made of a silicon-based material.
According to the above configuration, since the silicon material is excellent in heat resistance, alteration of the peeling layer due to heat is suppressed, and even when the ignition coil is used at a high temperature for a long time, the peeling property in the same layer can be maintained. it can.
[0091]
(5) The ignition coil according to any one of claims 1 to 6, wherein the ignition coil is accommodated in a plug hole of an engine.
In the ignition coil accommodated in the plug hole, the shape is limited and the internal potential gradient becomes extremely large. Therefore, when a partial defect occurs, durability and reliability tend to be greatly reduced. According to the said structure, generation | occurrence | production of the partial defect in insulating resin resulting from a thermal stress and a residual stress in such an ignition coil is suppressed, and durability and reliability of an ignition coil can be improved.
[0092]
【The invention's effect】
  In the invention described in claim 1, the outer periphery of the outer winding body is covered with a film.At the same time, the innermost layer of the outer winding body is formed as an aligned winding layer that restricts the penetration of the insulating resin.So thatWith the cooperation of these films and the innermost layer,It becomes difficult for the insulating resin filled in the case to enter the gaps between the layers of the outer winding body. For this reason, each winding layer of the outer winding body is not bonded by the insulating resin, or even if bonded, it becomes partial, and the gap between the winding layers of the outer winding body can be enlarged. When the gap is enlarged, thermal shrinkage and curing shrinkage are absorbed, and thermal stress and residual stress generated in the insulating resin are relaxed. As a result, the occurrence of partial defects in the insulating resin due to excessive thermal stress or residual stress is suppressed, and the durability and reliability of the ignition coil can be improved.
[0093]
  In the invention described in claim 2, at least one side is an outer winding body that contacts the same side orBetween the outermost layer of the outer winding body and the caseA film having releasability with respect to the insulating resin is used. Therefore, the heat shrinkage generated in the insulating resin due to the fact that one surface of the film having peelability does not adhere to the outer winding body or the insulating resin, and the gap between the film and the outer winding body or the insulating resin is enlarged. And cure shrinkage becomes absorbed. For this reason, even if the insulating resin penetrates into the gaps between the winding layers of the outer winding body and the winding layers are bonded by the insulating resin, the thermal stress and residual stress generated in the insulating resin are reliably reduced. Will come to be. As a result, the occurrence of partial defects in the insulating resin due to excessive thermal stress and residual stress is reliably suppressed, and the durability and reliability of the ignition coil can be improved.
[0094]
  In the invention described in claim 3, at leastPiecesurfaceButThe outer winding body and the film between the outer winding body and the insulating resin are peelable.onlyTo intervene. Therefore, one surface of the film having peelability does not adhere to the outer winding body or the insulating resin, and the thermal shrinkage and curing shrinkage generated in the insulating resin increase the gap between the film and the outer winding body. Therefore, the thermal stress and residual stress of the resin are reduced. In addition, the film is between the outer windings.onlyTherefore, both the inner peripheral portion and the outer peripheral portion of the outer winding body are covered with the insulating resin. As a result, the occurrence of partial defects in the insulating resin can be suppressed, the durability and reliability of the ignition coil can be improved, and the mechanical strength of the outer winding body can be substantially increased.
[0095]
  In the invention described in claim 4, at leastPiecesurfaceButAn outer winding body in contact with the same surface orInsideFilm with peelability for resinAt the boundary between the outer winding body and the inner resinThe inner periphery of the outer winding body is covered. Therefore, peelabilityHaveOne side of the film and the outer winding orInsideThe resin does not adhere, and the film and the outer winding orInsideAn expandable gap exists between the resin and the resin. Therefore, since the thermal contraction and curing shrinkage generated in the insulating resin are absorbed by the expansion of the gap, the thermal stress and residual stress of the resin are reduced. As a result, the occurrence of partial defects in the insulating resin is suppressed, and the durability and reliability of the ignition coil can be improved.
[0096]
  In the invention described in claim 5, at leastPiecesurfaceButOuter core in contact with the same surface orOutside resinFilm with peelabilityIs provided at the boundary between the outer core and the outer resin.The inner periphery of the outer core is covered. Therefore, one side of the peelable film and the outer core orOutsideResin does not adhere to the resin, and heat shrinkage and curing shrinkage that occur in the insulating resinOutsideBecause the gap between the resin and the resin is absorbedInsulationThe thermal stress and residual stress of the resin are reduced. As a result, the occurrence of partial defects in the insulating resin is suppressed, and the durability and reliability of the ignition coil can be improved.
[0097]
  In the invention described in claim 6,InsideResin andOutsideresinOneAt least insidePiecesurfaceButFilm with releasability from insulating resinArrangeI try to put it. Accordingly, the one surface of the film having peelability does not adhere to the insulating resin, and the thermal shrinkage and curing shrinkage generated in the insulating resin are absorbed by the expansion of the gap between the film and the insulating resin. The thermal stress and residual stress of the resin are reduced. As a result, the occurrence of partial defects in the insulating resin is suppressed, and the durability and reliability of the ignition coil can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an ignition coil according to a first embodiment.
FIG. 2 is a partially enlarged cross-sectional view of FIG.
FIG. 3 is a perspective view showing a procedure for forming a winding body.
FIG. 4 is a partially enlarged sectional view of an ignition coil.
FIG. 5 is a cross-sectional view of a film.
FIG. 6 is a partially enlarged sectional view of an ignition coil according to a second embodiment.
FIG. 7 is a partially enlarged sectional view of an ignition coil.
FIG. 8 is a partially enlarged cross-sectional view of an ignition coil according to a third embodiment.
FIG. 9 is a partially enlarged cross-sectional view of an ignition coil.
FIG. 10 is a partially enlarged sectional view of an ignition coil according to a fourth embodiment.
FIG. 11 is a partially enlarged cross-sectional view of an ignition coil.
FIG. 12 is a partially enlarged cross-sectional view of an ignition coil according to a fifth embodiment.
FIG. 13 is a partially enlarged cross-sectional view of an ignition coil.
FIG. 14 is a partially enlarged sectional view of an ignition coil according to a sixth embodiment.
FIG. 15 is a partially enlarged sectional view of an ignition coil.
FIG. 16 is a cross-sectional view of a conventional ignition coil.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Ignition coil, 11 ... Case, 12 ... Inner core, 13 ... Secondary coil, 14 ... Primary coil, 15 ... Outer core, 16 ... Insulating layer, 30 ... Secondary bobbin, 32 ... Secondary winding, 34 ... 1 Next winding, 35 ... winding body, 35a ... inner peripheral layer, 35b ... outer peripheral layer, 40 ... film, 41 ... base layer, 42 ... release layer, 43 ... adhesive layer, G ... gap.

Claims (6)

An inner winding body and an outer winding body, each of which is formed by laminating windings , are accommodated in a case, and the outermost winding is provided between the innermost layer of the outer winding body and the inner winding body . In the ignition coil in which an insulating resin is filled and cured between the outermost layer of the body and the case ,
Rutotomoni comprises a film covering the outermost layer of the outer winding body, through cooperation between the said outer winding bodies innermost layer is wound regularly of the film to the outer winding of the layers The intrusion of the insulating resin is restricted, and when the insulating resin is contracted, the radial winding is allowed between the innermost layer and the outermost layer of the outer winding body.
An ignition coil characterized by that. The ignition coil of 請 Motomeko 1,
At least one surface of the film has peelability with respect to the outer winding body contacting the same surface or the insulating resin between the outermost layer of the outer winding body and the case.
An ignition coil characterized by that. An inner winding body and an outer winding body, each of which is formed by stacking windings , are accommodated in a case, and between the outer winding and the inner winding body and between the outer winding body and the case. In the ignition coil in which insulating resin is filled and cured in between ,
Least even single plane is interposed a film having a releasing property to the outer winding member and the insulating resin only between the layers of the outer coil body
An ignition coil characterized by that. An inner winding body and an outer winding body, each of which is formed by laminating the windings , are accommodated in a case, and an inner resin that is an insulating resin between the outer winding body and the inner winding body, In the ignition coil formed by filling and curing the outer resin, which is an insulating resin, between the outer winding body and the case ,
Said outer winding by a film having a releasing property to the outer winding member or the inner resin provided at the boundary portion between the outer winding member and the inner resin least even-sided contacts against the surface The inner periphery of the wire was covered
An ignition coil characterized by that. And inner winding member each winding comprising wound laminated winding and an outer winding body and a tubular outer core is housed in the case, the outer winding body and the inner winding body inside the outer core is An inner resin that is an insulating resin is disposed between the outer winding body and the inner winding body, and an outer resin that is an insulating resin is disposed between the outer winding body and the outer core. In an ignition coil that is filled and cured,
Least even single face was coated with an inner peripheral portion of the outer core by providing a film having a releasing property to the outer core or the outer resin in contact against the surface in the boundary portion between the outer resin and the outer core
An ignition coil characterized by that. An inner winding body and an outer winding body, each of which is formed by laminating the windings , are accommodated in a case, and an inner resin that is an insulating resin between the outer winding body and the inner winding body, In the ignition coil formed by filling and curing the outer resin, which is an insulating resin, between the outer winding body and the case ,
The inner resin and hand least even-sided inside of the outer resin was placed a film having a releasing property to insulation resin
An ignition coil characterized by that.

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