JP2004253818A - Ignition coil for internal-combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil which generates a desired high voltage, by restraining the occurrence of cracks near the corners of both ends in the axis direction of a center core part. <P>SOLUTION: A rubber cylindrical member 17 is integrally molded in the shape of a cylindrical bag. The cylindrical member 17 covers the outer peripheral side surface of a center core part 12 comprising a core body 13 and permanent magnets 14 and 15, the corners of both the ends in the axial direction and a part of both end surfaces in the axial direction. Consequently, since cracks are prevented from occurring at the periphery of the outer peripheral side surface of the center core part 12, and a secondary spool 20 near the corners of both the ends of the center core part 12 and an epoxy resin 26, where the cracks are especially easy to occur, discharging between a high-voltage part and the center core part 12 is prevented. Further, by making the cylindrical member 17 deform elastically so that forces that the center core part 12 receives in the radial direction and the axial direction is relaxed, magnetostriction will not be generated at the center core part 12. Consequently, a desired high voltage is applied to an ignition plug. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an ignition coil for an internal combustion engine, and more particularly to a stick-shaped ignition coil for an internal combustion engine that is directly mounted on a plug hole.

  As a conventional stick-shaped ignition coil for an internal combustion engine (hereinafter, an “ignition coil for an internal combustion engine” is referred to as an ignition coil), a central core portion having a rod-shaped core body is disposed around an axis, and a primary coil and 2. Description of the Related Art It is known that a resin spool around which a secondary coil is wound is provided, and a resin is filled in a housing of the ignition coil as an insulating material between members. The resin filling the housing not only serves as an insulating material but also permeates between the wire members of the coil and plays a role in preventing winding collapse of the coil. There is also known an ignition coil in which a permanent magnet is provided on at least one of both ends in the axial direction of a core body to form a central core portion and increase a voltage generated by the ignition coil.

  However, in a state where not only the resin insulating material but also a case member such as a spool surrounding the outer periphery of the central core portion is in direct contact with the central core portion, the temperature changes between the central core portion having a different expansion coefficient and the resin insulating material or the case member. When expansion and contraction are repeated, the resin insulation material and the case member in contact with the central core portion, particularly the resin insulation material and the case member in contact with the axial end corners of the central core portion, have cracks (insulation deficient portions). crack) may occur. If a crack occurs in the resin insulating material or the case member around the central core, there is a risk of discharging through the crack between the secondary coil or the high voltage terminal as the high voltage part and the central core as the low voltage part. . When a discharge occurs between the high-voltage part and the central core, the insulation between the high-voltage part and the central core is broken, and the voltage generated in the secondary coil decreases. Cannot be applied.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide an ignition coil that prevents a crack from being generated in the vicinity of both end corners in the axial direction of a central core portion and generates a desired high voltage.

  According to the ignition coil according to the first and second aspects of the present invention, the central core portion composed of a rod-shaped core body or a permanent magnet disposed on at least one of both ends of the rod-shaped core body and the core body in the axial direction is provided. The axial end corners are covered with cushioning members. Accordingly, it is possible to prevent a case member such as a spool surrounding the outer periphery of the central core portion and a resin insulating material from directly contacting an axial end corner portion of the central core portion, and to prevent the central core portion from being in contact with the resin insulating material and the case member. The buffer member absorbs the difference in the expansion coefficient of the resin, so that even if the resin insulating material or the case member having a different expansion coefficient from the center core part together with the center core part repeatedly expands and contracts with a change in temperature, the cushion member covers the core member. It is possible to prevent a crack as an insulation defect portion from occurring in the resin insulating material and the case member near the axial end corner of the central core portion. This prevents discharge between the secondary coil or high-voltage terminal as the high-voltage part and the central core as the low-voltage part, and prevents dielectric breakdown between the high-voltage part and the central core. Therefore, it is possible to prevent the voltage generated in the secondary coil from lowering and apply a desired high voltage to the spark plug.

  According to the ignition coil according to the fifth aspect of the present invention, since the cushioning member is formed in a bag shape, the cushioning member can be integrally formed. As a result, the number of parts is reduced and the number of assembling steps is reduced. Furthermore, since a hole having a diameter smaller than the diameter of the central core portion is provided in at least one of both ends in the axial direction of the cushioning member, the core body and the permanent magnet are inserted into the cushioning member from the hole of the integrally formed cushioning member. Can be inserted.

  According to the ignition coil according to the sixth and seventh aspects of the present invention, since the buffer member is composed of a plurality of members, the manufacture of the buffer member is facilitated. According to the ignition coil according to the eighth, ninth or tenth aspect of the present invention, since the center core portion and the cushioning member are integrally formed, the cushioning member does not fall off from the center core portion at the time of assembling, and the assembling is easy. become. Here, the integral molding means that the cushioning member formed on the central core portion is not detachable and forms a part as a whole with the cushioning member formed on the outer periphery of the central core portion.

  According to the ignition coil according to the eleventh aspect of the present invention, since the buffer member covers the entire surface of the center core, the center core does not come into contact with the resin insulating material or the case member. Therefore, generation of cracks in the resin insulating material and the case member around the central core portion can be prevented. According to the ignition coil according to the twelfth aspect of the present invention, since the end corners of the center core are chamfered, it is possible to prevent cracks from being generated in the buffer member in contact with the end corners of the center core.

  According to the ignition coil according to the thirteenth aspect of the present invention, both ends of the center core portion including the rod-shaped core body, or the rod-shaped core body, and the permanent magnets disposed on at least one of the axial ends of the core body. One of the corners faces the space, and the other of the two corners faces the space or is covered by the cushioning member. Accordingly, a case member such as a spool surrounding the outer periphery of the central core portion and a resin insulating material do not contact the corner portions at both axial ends of the central core portion. Therefore, even if the resin insulating material and the case member having a different expansion coefficient from the central core portion together with the central core portion repeatedly expand and contract with the temperature change, the resin insulating material near the axial end corner of the central core portion and It is possible to prevent the case member from cracking as an insulation defect. This prevents discharge between the secondary coil or high-voltage terminal as the high-voltage part and the central core as the low-voltage part, and prevents dielectric breakdown between the high-voltage part and the central core. Therefore, it is possible to prevent the voltage generated in the secondary coil from lowering and apply a desired high voltage to the spark plug.

  According to the ignition coil according to claim 16 of the present invention, by providing another buffer member at at least one of both ends in the axial direction of the central core portion, the central core portion having a different expansion coefficient from the resin insulating material or the case. Even if the member repeatedly expands and contracts with a change in temperature, it is possible to reduce the load applied from the resin insulating material or the case member in the axial direction of the central core portion. Therefore, the occurrence of magnetostriction in the central core portion can be prevented, so that the voltage generated in the secondary coil can be prevented from lowering and a desired high voltage can be applied to the ignition plug.

  According to the ignition coil of the present invention, the other cushioning member also serves as a sealing member between the axial end surface of the central core and the case member, so that the axial end angle of the central core is provided. It is possible to prevent the resin insulating material from entering the portion with a small number of parts. This reduces the number of assembly steps.

  Hereinafter, a plurality of examples showing embodiments of the present invention will be described with reference to the drawings.

  (First Embodiment) FIGS. 1 to 4 show an ignition coil according to a first embodiment of the present invention.

  The ignition coil 10 shown in FIG. 1 is housed in a plug hole formed for each cylinder above an engine block (not shown), and is electrically connected to an ignition plug (not shown) on the lower side of FIG. The ignition coil 10 includes a cylindrical housing 11 made of a resin material. A housing 11a formed in the housing 11 has a central core 12, a secondary spool 20, a secondary coil 21, a primary spool 23, The primary coil 24, the outer core 25, and the like are housed. The central core portion 12 includes a core body 13 and permanent magnets 14 and 15 disposed at both ends of the core body 13. The epoxy resin 26 filled in the accommodating chamber 11a penetrates between the members in the ignition coil 10 to ensure electrical insulation between the members as a resin insulating material.

  The cylindrical rod-shaped core body 13 is assembled by laminating thin silicon steel plates in the radial direction so that the cross section is substantially circular. The permanent magnets 14 and 15 have polarities opposite to the direction of the magnetic flux generated when excited by the coil. Further, the outer periphery of the core body 13 is covered with a rubber cylindrical member 17 as a first buffer member which is a buffer member. Further, a cap 19 having a through hole is fitted to the permanent magnet 14 covered by the cylindrical member 17. The cap 19 and the secondary spool 20 constitute a case member surrounding the outer periphery of the central core portion 12.

  The cylindrical member 17 is integrally formed in a cylindrical bag shape as shown in FIG. The cylindrical member 17 is located between the cylindrical portion 17a, the annular portions 17b and 17c provided at both ends in the axial direction of the cylindrical portion 17a and having a through hole 18 in the center, and the cylindrical portion 17a and the annular portions 17b and 17c. Corner 17d. As shown in FIGS. 3 and 4, the cylindrical portion 17 a covers the outer peripheral side surface of the central core portion 12, the annular portions 17 b and 17 c cover a part of both axial end surfaces of the central core portion 12, and the corner portion 17 d is located at the center. The end corners of the permanent magnets 14 and 15 which are the end corners of the core 12 are covered. The annular portions 17b and 17c are formed so as to be thicker than the cylindrical portion 17a, and constitute a second buffer member which is a buffer member. Since the diameter of the through hole 18 is smaller than the diameter of the permanent magnets 14 and 15, the core body 13 and the permanent magnets 14 and 15 are inserted into the cylindrical member 17 while expanding the through hole 18.

  As shown in FIG. 1, the secondary spool 20 is provided on the outer periphery of the cylindrical member 17, and is formed of a resin material into a closed-end cylindrical shape with the permanent magnet 15 side closed. The secondary coil 21 is wound around the outer periphery of the secondary spool 20, and a dummy coil 22 is further wound around the high voltage side of the secondary coil 20 in a single winding. The dummy coil 22 electrically connects the secondary coil 21 and the terminal plate 40. By electrically connecting the secondary coil 21 and the terminal plate 40 with the dummy coil 22 instead of a single wire, the surface area of the electrical connection between the secondary coil 21 and the terminal plate 40 is increased, and the electrical connection is made. Avoid electric field concentration.

  The primary spool 23 is provided on the outer periphery of the secondary coil 21 and is formed of a resin material. The primary coil 24 is wound around the primary spool 23. A switching circuit for supplying a control signal to the primary coil 24 is provided outside the ignition coil 10, and the primary coil 24 and a switching circuit (not shown) are electrically connected to each other via a terminal formed by insert-molding the connector 30. I have.

  The outer core 25 is mounted further outside the primary coil 24. The outer peripheral core 25 is formed by winding a thin silicon steel sheet in a cylindrical shape and does not connect the winding start end and the winding end end, and thus forms a gap in the axial direction. The outer peripheral core 25 has an axial length extending from the outer peripheral position of the permanent magnet 14 to the outer peripheral position of the stone 15. The high-voltage terminal 41 is insert-molded below the housing 11. The central portion of the terminal plate 40 forms a claw portion bent in the direction in which the high-voltage terminal 41 is inserted. The high-voltage terminal 41 is electrically connected to the terminal plate 40 by inserting the tip of the high-voltage terminal 41 into the claw portion. The wire at the high voltage end of the dummy coil 22 is electrically connected to the terminal plate 40 by fusing or soldering. The spring 42 is electrically connected to the high voltage terminal 41 and is electrically connected to the ignition plug when the ignition coil 10 is inserted into the plug hole. A plug cap 43 made of rubber is attached to the open end of the housing 11 on the high voltage side, and an ignition plug is inserted into the plug cap 43. When a control signal is supplied from the switching circuit to the primary coil 24, a high voltage is generated in the secondary coil 21, and this high voltage is applied to the ignition plug via the dummy coil 22, the terminal plate 40, the high voltage terminal 41, and the spring 42. .

  Next, the operation of the ignition coil 10 according to the temperature change will be described. The expansion coefficients of the secondary spool 20 and the epoxy resin 26 surrounding the outer periphery of the central core section 12 are different from the expansion coefficients of the core body 13 and the permanent magnets 14 and 15 which constitute the central core section 12. Usually, the expansion coefficients of the secondary spool 20 and the epoxy resin 26 are larger than the expansion coefficient of the central core portion 12. Therefore, if the center core portion 12 is not covered with the cylindrical member 17 and the secondary spool 20 or the epoxy resin 26 is in direct contact with the center core portion 12, the temperature change causes the center core portion 12 and the secondary spool 20. When the epoxy resin 26 repeatedly expands and contracts, cracks may occur in the secondary spool 20 and the epoxy resin 26 that are in contact with the central core 12. In particular, cracks are likely to occur in the secondary spool 20 and the epoxy resin 26 that are in contact with the end corners of the permanent magnets 14 and 15. If a crack occurs in the secondary spool 20 or the epoxy resin 26 which is in contact with the corners of the end portions of the permanent magnets 14 and 15, the high voltage side of the secondary coil 21 which is a high voltage portion, the dummy coil 22, the terminal plate 40 or the high voltage terminal Discharge may occur through a crack between the central core portion 12 and the low voltage portion. When a discharge occurs between the high-voltage portion and the central core portion 12, the insulation between the high-voltage portion and the central core portion 12 is broken, and the voltage generated in the secondary coil decreases. It cannot be applied.

  However, in the first embodiment, the outer peripheral side surface of the central core portion 12 and the end corners of the permanent magnets 14 and 15 are covered with the cylindrical member 17 made of an elastic material. The end portion 15 is prevented from coming into direct contact with the secondary spool 20 or the epoxy resin 26. Furthermore, even if the center core portion 12 and the secondary spool 20 and the epoxy resin 26 which have different expansion rates due to the temperature change repeatedly expand and contract, the difference in the expansion rates is absorbed by the cylindrical member 17 being elastically deformed. Can be. Accordingly, it is possible to prevent the secondary spool 20 and the epoxy resin 26 from being cracked around the outer peripheral side surface of the central core portion 12 and especially near both corners of the central core portion 12 where cracks are easily generated. It is possible to prevent discharge from occurring between the portion and the central core portion 12. Thereby, a desired high voltage can be applied to the ignition plug.

  Also, since the expansion coefficient of the cap 19, the secondary spool 20, and the epoxy resin 26 is different from the expansion coefficient of the central core portion 12 composed of the core body 13 and the permanent magnets 14 and 15, it is large. Due to the contraction of the next spool 20 and the epoxy resin 26, a force acts to contract the central core portion 12 in the radial direction and the axial direction. For this reason, a load is applied to the central core portion in the radial direction and the axial direction from the resin insulating material and the case member due to a difference in expansion coefficient. In particular, when a load is applied to the central core portion in the axial direction, the magnetic permeability of the core body may decrease (hereinafter, “permeability decreases due to the load on the central core portion” is referred to as magnetostriction), and the ignition coil There is a problem that the generated voltage decreases. That is, when a force is applied in the axial direction of the central core portion 12, magnetostriction in which the magnetic permeability of the core main body 13 decreases occurs, and the voltage generated in the secondary coil 21 may decrease. However, since the cylindrical portion 17a covers the outer peripheral side surface of the central core portion 12 and the annular portions 17b and 17c that are thicker than the cylindrical portion 17 cover a part of both ends in the axial direction, the cylindrical member 17 is elastically deformed so that The force applied to the core 12 in the axial direction is reduced, and no magnetostriction occurs in the core body 13. Thereby, a desired high voltage can be applied to the ignition plug.

  In the first embodiment, the permanent magnets 14 and 15 are provided at both ends of the core body 13, but permanent magnets may be provided only at one end of the core body 13.

(Second embodiment)
FIG. 5 shows an ignition coil according to a second embodiment of the present invention. Components substantially the same as those in the first embodiment are denoted by the same reference numerals.

  In the second embodiment, a permanent core is not disposed at both ends of the core main body 27, and the core main body 27 alone forms a central core portion. The cylindrical member 17 covers the outer peripheral side surface, both end corners, and part of both end surfaces of the core main body 27. Accordingly, also in the second embodiment, cracks are prevented from being generated around the outer peripheral side surface of the core main body 27, and especially near the corners at both ends of the core main body 27 where cracks are easily generated. Therefore, it is possible to prevent discharge between the high voltage portion and the central core portion 12. Thereby, a desired high voltage can be applied to the ignition plug.

  Further, since the cylindrical member 17 is elastically deformed, the force applied to the core main body 27 in the radial direction and the axial direction is reduced, and no magnetostriction occurs in the core main body 27. Thereby, a desired high voltage can be applied to the ignition plug.

(Third embodiment)
6 and 7 show an ignition coil according to a third embodiment of the present invention. Components substantially the same as those in the first embodiment are denoted by the same reference numerals.

  The rubber tubular member 50 as the first cushioning member includes a cylindrical portion 50a, a corner portion 50b, and a disk portion 50c which is also a second cushioning member, and has a cylindrical bag shape with a closed bottom with the permanent magnet 15 side closed. Is molded. The cylindrical portion 50a covers the outer peripheral side surface of the central core portion 12, the annular corner portion 50b covers the end corner portion of the permanent magnet 15, and the disk portion 50c covers the end surface of the permanent magnet 15. The tubular member 50 is formed on the permanent magnet 14 side so as to extend beyond the end face of the permanent magnet 14. The rubber plate member 51 as the first buffer member and the second buffer member is formed in a circular shape separately from the cylindrical member 50, and has a larger diameter than the permanent magnet 14. The end corners of the permanent magnet 14 are covered by the cylindrical member 50 and the plate member 51, and the end surface of the permanent magnet 14 is covered by the plate member 51. Further, since the plate member 51 seals the gap between the cap 19 as the case member and the permanent magnet 14, the epoxy resin 26 does not enter the central core portion 12.

  Also in the third embodiment, cracks are prevented from being generated around the outer peripheral side surface of the central core portion 12, and especially near the corners at both ends of the central core portion 12 where cracks are easily generated. Therefore, it is possible to prevent discharge between the high voltage portion and the central core portion 12. Thereby, a desired high voltage can be applied to the ignition plug.

  Furthermore, since the cylindrical member 50 and the plate member 51 are elastically deformed, the force applied to the central core portion 12 in the radial direction and the axial direction is reduced, and no magnetostriction occurs in the central core portion 12. Thereby, a desired high voltage can be applied to the ignition plug. The first cushioning member is composed of two members, a tubular member 50 and a plate member 51. Since the tubular member 50 is formed into a bottomed tubular shape having no end face at one end in the axial direction, the first cushioning member is provided. The manufacture of the member is easy.

(Fourth embodiment)
FIGS. 8 and 9 show an ignition coil according to a fourth embodiment of the present invention. Components substantially the same as those of the third embodiment are denoted by the same reference numerals. A rubber tubular member 52 as a first cushioning member includes a cylindrical portion 52a, a corner portion 52b, and an annular portion 52c, and is formed into a cylindrical bag shape. The cylindrical portion 52a covers the outer peripheral side surface of the central core portion 12, the annular corner portion 52b covers an end corner portion of the permanent magnet 15, and the annular portion 52c covers a part of the end surface of the permanent magnet 15. The cylindrical portion 52a extends toward the permanent magnet 14, but its end does not reach the end surface of the permanent magnet 14.

  The rubber plate members 53 and 54 as the second buffer members are formed in a circular shape separately from the cylindrical member 52. The plate members 53 and 54 are smaller in diameter than the permanent magnets 14 and 15, and are in contact with the end faces of the permanent magnets 14 and 15, respectively. As shown in FIG. 8, the end corner of the permanent magnet 14 faces the space 100 and is not in contact with any member. Further, since the plate member 53 seals the gap between the cap 19 as the case member and the permanent magnet 14, the epoxy resin 26 does not enter the central core portion 12.

  In the fourth embodiment, since the end corners of the permanent magnet 14 face the space 100 and the end corners of the permanent magnet 15 are covered with the cylindrical member 52, both ends of the central core 12 in the axial direction are provided. The corner is not in contact with the secondary spool 20 or the epoxy resin 26. Further, since the cylindrical portion 52a covers the outer peripheral side surface of the center core portion 12, even if the center core portion 12, the secondary spool 20, and the epoxy resin 26 repeatedly expand and contract with a change in temperature, the center core portion 12 is not covered. Since the secondary spool 20 and the epoxy resin 26 are prevented from generating cracks around the outer peripheral side surface, and especially near both corners of the central core portion 12 where cracks are easily generated, the high voltage portion and the central core portion 12 are prevented from cracking. It is possible to prevent discharge between the two. Thereby, a desired high voltage can be applied to the ignition plug.

  Further, the elastic deformation of the plate members 53 and 54 reduces the force applied to the central core portion 12 in the radial and axial directions, so that magnetostriction does not occur in the central core portion 12. Thereby, a desired high voltage can be applied to the ignition plug. Further, since the plate member 53 serving as the second cushioning member also serves as a seal member between the end face of the permanent magnet 14 and the cap 19, the number of parts is reduced and the number of assembling steps is reduced.

  In the fourth embodiment, the end corner of the permanent magnet 14 faces the space 100 and is not in contact with other members. However, the end corner of the permanent magnet 15 may face the space. Alternatively, both end corners of the permanent magnets 14 and 15 may face the space. In the above-described plurality of embodiments of the present invention, at least one of the outer peripheral side surface of the central core portion and the both end corners in the axial direction is covered with the cylindrical member serving as the first buffer member, and the other is covered with the cylindrical member, It faces the space. Therefore, it is possible to prevent the secondary spool 20 and the epoxy resin 26 having different expansion coefficients from the center core portion from coming into contact with the outer peripheral side surface and the corners at both ends of the center core portion, and to elastically deform the first cushioning member. It absorbs the difference in expansion rate. Therefore, even if the center core portion, the secondary spool 20 and the epoxy resin 26 repeatedly expand and contract with the temperature change, the periphery of the outer peripheral side surface of the center core portion, and especially the axial direction of the center core portion where cracks are liable to occur. Cracks can be prevented from occurring in the secondary spool 20 and the epoxy resin 26 near the corners at both ends. This can prevent a discharge from occurring along a crack between the high-voltage portion and the central core portion, which is a low-voltage portion, in the ignition coil, so that a desired high voltage can be applied to the ignition plug. .

  Further, the outer peripheral side surface of the central core portion is covered by the cylindrical member, and both end surfaces in the axial direction of the central core portion are covered by the cylindrical member or the plate member as the second cushioning member. Even if the secondary spool 20 and the epoxy resin 26 having different expansion rates from the core part expand and contract, the cylindrical member or the plate member is elastically deformed, so that the force applied to the central core part in the radial direction and the axial direction is reduced. You. Therefore, a desired high voltage can be applied to the ignition plug without generating magnetostriction in the central core portion.

  In the above embodiments, the cylindrical member as the first cushioning member extends in the axial direction of the central core, and is formed so as to cover at least one end corner of the central core and the outer peripheral side surface. However, the first cushioning member may be composed of a plurality of members, and the first cushioning member may cover only the end corners of the central core portion. In the above embodiments of the present invention, the cylindrical member and the plate member are formed of rubber. However, the cylindrical member and the plate member may be formed of an elastomer resin, and the center core portion may be insert-molded in the cylindrical member. Further, the center core may be inserted into a cylindrical member formed of an elastomer resin.

  In addition, an elastic member such as an elastomer resin or rubber may cover the surface of the center core portion 12 to form the first cushioning member by integral molding by injection molding, baking, or dipping. In this case, the first cushioning member may cover the entire surface of the central core 12, or may have a small through hole at one end to identify the end of the central core 12. By integrally molding the center core portion 12 and the first cushioning member, the first cushioning member does not drop off from the center core portion 12 at the time of assembly, thereby facilitating assembly.

  Also, the first buffer member is formed by mounting the permanent magnets 14 and 15 on the core body 13 in advance to form the central core portion 12, covering the central core portion 12 with the heat-shrinkable tube, and thermally shrinking the heat-shrinkable tube. It may be formed. In addition, the corners of the center core 12, that is, the corners of the permanent magnets 14 and 15 are chamfered by grinding or grinding them so that they come into contact with the corners of the center core 12. The first buffer member may be prevented from being damaged.

1 is a cross-sectional view illustrating an ignition coil according to a first embodiment of the present invention. It is sectional drawing which shows the cylinder member of 1st Example. FIG. 3 is an enlarged view of a portion taken along line III of FIG. 1. FIG. 4 is an enlarged view of an IV line portion in FIG. 1. FIG. 4 is a sectional view illustrating an ignition coil according to a second embodiment of the present invention. FIG. 7 is a sectional view showing one end of an ignition coil according to a third embodiment of the present invention. It is sectional drawing which shows the other end of the ignition coil by 3rd Example. FIG. 11 is a sectional view showing one end of an ignition coil according to a fourth embodiment of the present invention. It is sectional drawing which shows the other end part of the ignition coil by 4th Example.

Explanation of reference numerals

Reference Signs List 10 ignition coil 11 housing 12 central core 13 core body (central core)
14, 15 permanent magnet (center core)
17 Tube member (first buffer member, second buffer member)
17b, 17c annular portion (second buffer member)
17d corner (first cushioning member)
18 Through hole 19 Cap (case member)
20 Secondary spool (case member)
21 secondary coil 23 primary spool 24 primary coil 25 outer core 26 epoxy resin (resin insulating material)
27 core body (center core)
50 cylindrical member (first buffer member, second buffer member)
50c disk part (second buffer member)
51 plate member (first buffer member, second buffer member)
52 cylindrical member (first buffer member)
53, 54 plate member (second buffer member)
100 space

Claims (17)

An internal combustion engine ignition coil that generates a high voltage applied to an internal combustion engine ignition device,
A central core portion composed of a rod-shaped core body and filled with a resin insulating material,
A primary spool and a secondary spool disposed on the outer periphery of the center core,
A primary coil wound on the primary spool, and a secondary coil wound on the secondary spool,
A cushioning member that covers an axial end corner of the central core portion,
An ignition coil for an internal combustion engine, comprising: The ignition coil for an internal combustion engine according to claim 1, wherein the center core portion further includes a permanent magnet disposed on at least one of both axial ends of the core body. The said central core part, the said primary spool, the said secondary spool, the said primary coil, and the said secondary coil are accommodated in the accommodation chamber of a housing, The Claim 1 characterized by the above-mentioned. Ignition coil for internal combustion engine. The ignition coil for an internal combustion engine according to claim 3, wherein a resin insulating material is filled in the housing chamber of the housing. The said buffer member is formed in the shape of a bag, The hole which has a diameter smaller than the diameter of the said center core part is provided in at least any one of the axial direction both ends of the said center core part, The Claims 1 thru | or 2 characterized by the above-mentioned. 5. The ignition coil for an internal combustion engine according to claim 4. The ignition coil according to any one of claims 1 to 5, wherein the buffer member includes a plurality of members. The ignition coil for an internal combustion engine according to claim 6, wherein the buffer member includes a buffer member that covers an outer peripheral side surface of the central core, and a buffer member that covers both axial ends of the central core. The ignition coil for an internal combustion engine according to claim 1, wherein the center core portion and the cushioning member are integrally formed. 9. The ignition coil according to claim 8, wherein the buffer member is made of an elastomer resin. The ignition coil for an internal combustion engine according to claim 1, wherein the shock-absorbing member comprises a heat-shrinkable tube. 9. The ignition coil for an internal combustion engine according to claim 1, wherein the cushioning member covers the entire surface of the central core portion. The ignition coil for an internal combustion engine according to any one of claims 1 to 9, wherein an end corner of the center core is chamfered. An internal combustion engine ignition coil that generates a high voltage applied to an internal combustion engine ignition device,
Filled with resin insulating material, a rod-shaped core body, or a central core portion made of a permanent magnet disposed on at least one of both ends in the axial direction of the rod-shaped core body and the core body,
A primary spool and a secondary spool disposed on the outer periphery of the center core,
A primary coil wound on the primary spool, and a secondary coil wound on the secondary spool,
A resin insulating material filled in the ignition coil,
One of the two corners in the axial direction of the central core portion faces a space, and the other of the two corners faces the space or is covered with a cushioning member. Ignition coil. 14. The ignition coil for an internal combustion engine according to claim 13, wherein the center core portion, the primary spool, the secondary spool, the primary coil, and the secondary coil are housed in a housing chamber of a housing. 14. The ignition coil for an internal combustion engine according to claim 13, wherein the housing chamber of the housing is filled with a resin insulating material. 14. The ignition coil for an internal combustion engine according to claim 13, wherein another buffer member is disposed on at least one of both ends in the axial direction of the central core portion. The another cushioning member seals between an axial end face of the central core portion where an end corner facing a space is located, and a case member surrounding the outer periphery of the central core portion. The ignition coil for an internal combustion engine according to claim 13, wherein