JPH1174139A - Ignition coil for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition coil which generates a desired high-voltage cracks from occurring near the corners at both the ends of a center core. SOLUTION: A rubber cylindrical member 17 is formed like a cylinder through integral molding. The cylindrical member 17 covers the outer side face, axial edge corners, and a part of axial edge faces of a center core 12 composed of a core main body 13 and permanent magnets 14 and 15. Therefore, cracks are prevented from occurring around the outer peripheral side edge of the center core 12, a secondary spool 20, and an epoxy resin 26 near the corners at both ends of the center core 12 where cracks are liable to occur, so that electric discharge is prevented from occurring between a high-voltage part and the center core 12. Furthermore, the cylindrical member 17 is elastically deformed, whereby a force applied to the center core 12 in both radial and axial directions can be relaxed, and magnetostriction is prevented from occurring in the center core 12. As a result of this setup, a desired high voltage can be applied to an ignition plug.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 directly mounted on a plug hole.

[0002]

2. Description of the Related Art A conventional stick-shaped ignition coil for an internal combustion engine (hereinafter referred to as an "ignition coil for an internal combustion engine" is referred to as an ignition coil) is provided with a central core portion having a rod-shaped core body disposed around an axis. There is a known type in which a resin spool having a primary coil and a secondary coil wound around the outer periphery thereof is provided, and a resin is filled in a housing of the ignition coil as an insulating material between members. The resin filled in 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 disposed 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.

[0003]

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 center core portion is in direct contact with the center core portion, the center core portion having a different expansion coefficient from the center core portion has a resin. When the insulating material and the case member repeatedly expand and contract due to a temperature change, the resin insulating material and the case member in contact with the central core portion, particularly the resin insulating material and the case in contact with the axial end corners of the central core portion. A crack, which is an insulation defect, may occur in the member. 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.

When the center core and the resin insulating material or the case member repeatedly expand and contract due to a change in temperature, the difference in the coefficient of expansion causes the center core to be loaded radially and axially from the resin insulating material and the case member. Receive. 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). There is a problem that the generated voltage decreases.

An object of the present invention is to provide an ignition coil that prevents cracks from being generated in the vicinity of both axial corners of a central core and generates a desired high voltage. It is another object of the present invention to provide an ignition coil that reduces a load applied to a central core portion due to a temperature change and generates a desired high voltage.

[0006]

According to the ignition coil of the present invention, the ignition coil is disposed on at least one of the rod-shaped core body, the rod-shaped core body, and both ends in the axial direction of the core body. Both end corners in the axial direction of the central core portion made of a permanent magnet are covered with a first cushioning member. 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 both end corners of the central core portion in the axial direction, and to prevent the central core portion from being in contact with the resin insulating material and the case member. Since the first buffer member absorbs the difference in the expansion coefficient, the first buffer member can be expanded even if the center core portion and the resin insulating material and the case member having different expansion coefficients from the center core portion repeatedly expand and contract with the temperature change. It is possible to prevent the resin insulating material and the case member in the vicinity of the two corners in the axial direction of the central core portion covered with the member from being cracked as an insulating defect. This prevents discharge between the secondary coil or high-voltage terminal as a high-voltage part and the central core as a 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 second aspect of the present invention, by disposing the second cushioning member on at least one of both ends in the axial direction of the central core portion, the central core portion and the central core portion are expanded. Even if the resin insulating material and the case member with different rates repeatedly expand and contract with the temperature change,
The load applied in the axial direction of the central core portion from the resin insulating material or the case member due to the difference in the expansion coefficient can be reduced. Therefore, generation of magnetostriction in the central core portion can be prevented, so that a 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 according to the third aspect of the present invention, since the first buffer member is formed in a bag shape, the first buffer member can be integrally formed. As a result, the number of parts is reduced and the number of assembling steps is reduced. Further, since a hole having a diameter smaller than the diameter of the center core portion is provided in at least one of both ends in the axial direction of the first buffer member, the first integrally formed first buffer member is formed.
The core body and the permanent magnet can be inserted into the first buffer member from the hole of the buffer member.

According to the ignition coil according to the fourth aspect of the present invention, since the first buffer member is composed of a plurality of members, the manufacture of the first buffer member is facilitated. According to the ignition coil according to the fifth, sixth or seventh aspect of the present invention, since the central core portion and the first cushioning member are integrally formed, the first cushioning member is dropped from the central core portion during assembly. And assembly becomes easy. Here, the integral molding means that the first cushioning member formed on the central core portion is not detachable and the first cushioning member is formed on the outer periphery of the central core portion to constitute one part as a whole. Means

According to the ignition coil of the present invention, since the first cushioning member covers the entire surface of the central core, the central 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 ninth aspect of the present invention, since the end corner of the center core is chamfered, it is possible to prevent a crack from being generated in the first cushioning member in contact with the end corner of the center core. Can be prevented.

According to the ignition coil of the present invention, the central core comprises a rod-shaped core body, or a rod-shaped core body, and a permanent magnet disposed on at least one of both axial ends of the core body. One of the corners at both ends of the portion faces the space, and the other of the corners faces the space or is covered by the first cushioning member. Therefore, a case member such as a spool surrounding the outer periphery of the central core portion and a resin insulating material are not in contact with both axial corner portions 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 a high-voltage part and the central core as a 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 of the present invention, by disposing the second cushioning member on at least one of both ends in the axial direction of the center core, the center core and the resin having different expansion coefficients are provided. Even if the insulating material and the case member repeatedly expand and contract with the temperature change, it is possible to reduce the load applied from the resin insulating material and the case member in the axial direction of the central core portion. Therefore, generation of magnetostriction in the central core portion can be prevented, so that a 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 according to the twelfth aspect of the present invention, since the second cushioning member also serves as a sealing member between the axial end face of the central core and the case member, the second cushioning member is disposed in the axial direction of the central core. It is possible to prevent the resin insulating material from entering the corners of the end with a small number of parts. This reduces the number of assembly steps.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; (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 11 a formed in the housing 11 has a center 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 a core body 1.
3 and permanent magnets 14 and 15 disposed at both ends.
The epoxy resin 26 filled in the accommodating chamber 11a penetrates between the members in the ignition coil 10 and ensures 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 becomes substantially circular. The permanent magnets 14 and 15 have polarities opposite to the direction of the magnetic flux generated by being excited by the coil. Further, the outer periphery of the core body 13 is covered with a rubber tubular member 17 as a first buffer member. Further, the cylindrical member 1
Cap 1 having a through hole in permanent magnet 14 covered with 7
9 are fitted. Cap 19 and secondary spool 2
Reference numeral 0 denotes 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 includes a cylindrical portion 17a,
The through holes 18 are provided at both ends in the axial direction of the cylindrical portion 17a.
And the corner portions 17 located between the cylindrical portion 17a and the annular portions 17b and 17c, respectively.
d. As shown in FIG. 3 and FIG.
7a covers the outer peripheral side surface of the central core portion 12,
Reference numerals b and 17c cover a part of both end surfaces in the axial direction of the center core portion 12, and corner portions 17d cover end corner portions of the permanent magnets 14 and 15, which are both end corners of the center core portion 12. Annular part 17
b and 17c are formed so as to be thicker than the cylindrical portion 17a, and constitute a second cushioning member. Through hole 18
Are smaller than the diameters 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 holes 18.

As shown in FIG. 1, the secondary spool 20 is disposed 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 is connected to the connector 3
The primary coil 24 and a switching circuit (not shown) are electrically connected to each other through a terminal that is insert-molded at 0.

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, so that a gap is formed 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. High pressure terminal 41 is housing 1
1 is insert-molded below. 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. By inserting the tip of the high-voltage terminal 41 into this claw portion, the high-voltage terminal 41 is electrically connected to the terminal plate 40. 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 mounted on 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, the secondary coil 2
1, a high voltage is generated, and this high voltage is applied to the dummy coil 22,
The voltage is applied to the ignition plug via 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 rates of the secondary spool 20 and the epoxy resin 26 surrounding the outer periphery of the center core 12 are determined by the core body 13, the permanent magnets 14, 15 constituting the center core 12.
Is different from the expansion coefficient. Normally, 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, the center core portion 12 is
Not covered with secondary spool 20 or epoxy resin 2
6 is in direct contact with the central core portion 12, the central core portion 12 and the secondary spool 20 or the epoxy resin 2
6 may repeatedly cause expansion and contraction, and cracks may occur in the secondary spool 20 and the epoxy resin 26 that are in contact with the central core portion 12. In particular, permanent magnets 14, 15
Secondary spool 20 or epoxy resin 2 that is in contact with the
Cracks easily occur in No. 6. When a crack occurs in the secondary spool 20 or the epoxy resin 26 in contact with the end corners 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
Alternatively, discharge may occur through a crack between the high voltage terminal 41 and the central core portion 12 which is a 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 corners of the magnets 14 and 15 are prevented from directly contacting the secondary spool 20 and the epoxy resin 26. Further, the center core portion 12 and the secondary spool 20 and the epoxy resin 2 having different expansion coefficients with the temperature change.
Even if 6 and 7 repeat expansion and contraction, the difference in expansion rate can be absorbed by the cylindrical member 17 being elastically deformed. Therefore, 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 section and the central core section 12. Thereby, a desired high voltage can be applied to the ignition plug.

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, and is large. 19, the contraction of the secondary spool 20 and the epoxy resin 26 exerts a force to shrink the center core portion 12 in the radial and axial directions. In particular, 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 is reduced occurs, and the voltage generated in the secondary coil 21 may be reduced. However, the outer peripheral side surface of the central core portion 12 is
And the annular portions 17b and 17c thicker than the cylindrical portion 17 cover a part of both ends in the axial direction. Therefore, when the cylindrical member 17 is elastically deformed, the force received by the central core portion 12 in the radial direction and the axial direction is reduced. As a result, magnetostriction does not occur 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. However, 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, the central core is constituted by the core main body 27 alone without providing permanent magnets at both ends of the core main body 27. 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. Therefore,
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 at the secondary spool 20 and the epoxy resin 26 near both corners of the core main body 27 where cracks are easily generated. In addition, 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, when the cylindrical member 17 is elastically deformed, the force applied to the core body 27 in the radial direction and the axial direction is reduced, and no magnetostriction occurs in the core body 27. Thereby, a desired high voltage can be applied to the ignition plug. (Third Embodiment) FIGS. 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.

Rubber cylindrical member 5 as first buffer member
Numeral 0 is composed of a cylindrical portion 50a, a corner portion 50b, and a disk portion 50c which is also a second cushioning member, and is formed into a bottomed cylindrical bag with the permanent magnet 15 side closed. 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 cylindrical member 50 is a permanent magnet 1
It is formed on the fourth 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. Permanent magnet 14
Are covered by the tubular member 50 and the plate member 51, and the end surface of the permanent magnet 14 is covered by the plate member 51. Furthermore, 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 occur around the outer peripheral side surface of the central core portion 12, and particularly at the secondary spool 20 and the epoxy resin 26 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.

Further, 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 and axial directions 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 buffer 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 buffer member is formed. 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. The rubber tubular member 52 as the first cushioning member includes a cylindrical portion 52a, a corner 5
2b and an annular portion 52c, and are formed in 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. Although the cylindrical portion 52a extends toward the permanent magnet 14,
Its end does not reach the end face of the permanent magnet 14.

Rubber plate member 5 as second buffer member
Reference numerals 3 and 54 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 center core 1
The epoxy resin 26 does not enter into 2.

In the fourth embodiment, 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 end corners in the direction are not in contact with the secondary spool 20 or the epoxy resin 26. Furthermore, since the cylindrical portion 52a covers the outer peripheral side surface of the central core portion 12, even if the central core portion 12, the secondary spool 20, and the epoxy resin 26 repeat expansion and contraction due to a temperature change, the central core portion 12 will Cracks are prevented from occurring in the secondary spool 20 and the epoxy resin 26 around the outer peripheral side surface, and particularly near the corners at both ends of the central core portion 12 where cracks are easily generated. It is possible to prevent discharge between the two. Thereby, a desired high voltage can be applied to the ignition plug.

Further, since the plate members 53 and 54 are elastically deformed, the force applied to the central core portion 12 in the radial and axial directions is reduced, and no magnetostriction occurs 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 corners on the permanent magnet 14 side face the space 100 and are not in contact with other members, but the end corners of the permanent magnet 15 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 corners at both ends 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 rates 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 cause the first cushioning member to be elastically deformed. 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 circumference of the outer peripheral side surface of the center core portion, and especially the axial direction of the center core portion where cracks easily occur are likely 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 axial end surfaces of the central core portion are covered by the cylindrical member or the plate member as the second buffer member. Even if the secondary spool 20 and the epoxy resin 26 having different expansion rates from the central core portion and the epoxy resin 26 expand and contract together with the central portion, the force applied to the central core portion in the radial direction and the axial direction by the elastic deformation of the cylindrical member or the plate member. Is alleviated. 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 central core portion may be inserted into a cylindrical member formed of an elastomer resin.

An elastic member such as an elastomer resin or rubber may cover the surface of the central 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 central core portion 12 and the first cushioning member, the first cushioning member does not fall off from the central core portion 12 at the time of assembling, so that the assembling becomes easy.

Further, a permanent magnet 14,
15 to form the central core 12 and the central core 1
The first shock-absorbing member may be formed by placing a heat-shrinkable tube on 2 and heat-shrinking the heat-shrinkable tube. Further, the end corners of the central core portion 12, that is, the permanent magnets 14,
By grinding and chamfering the corners of the end of the 15, the first cushioning member in contact with the corner of the end of the central core 12 may be prevented from being damaged.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an ignition coil according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a cylindrical member of the first embodiment.

FIG. 3 is an enlarged view of a portion taken along line III of FIG. 1;

FIG. 4 is an enlarged view of a portion taken along a line IV in FIG. 1;

FIG. 5 is a sectional view showing an ignition coil according to a second embodiment of the present invention.

FIG. 6 is a sectional view showing one end of an ignition coil according to a third embodiment of the present invention.

FIG. 7 is a sectional view showing the other end of the ignition coil according to the third embodiment.

FIG. 8 is a sectional view showing one end of an ignition coil according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view showing the other end of the ignition coil according to the fourth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ignition coil 11 Housing 12 Center core part 13 Core body (Center core part) 14, 15 Permanent magnet (Center core part) 17 Cylindrical member (1st buffer member, 2nd buffer member) 17b, 17c 2 buffer member 17d corner portion (first buffer member) 18 through hole 19 cap (case member) 20 secondary spool (case member) 21 secondary coil 23 primary spool 24 primary coil 25 outer peripheral core 26 epoxy resin (resin) Insulating material) 27 Core body (central core portion) 50 Cylindrical member (first buffer member, second buffer member) 50c Disk portion (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

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kazuhide Kawai 1-1-1, Showa-cho, Kariya-shi, Aichi Pref.

Claims (12)

[Claims] An internal combustion engine ignition coil for generating a high voltage applied to an ignition device of an internal combustion engine, comprising: a rod-shaped core body; or at least one of a rod-shaped core body and both ends in the axial direction of the core body. A primary core and a secondary spool disposed on the outer periphery of the central core, a primary coil wound around the primary spool, and the secondary spool. An internal combustion system comprising: a wound secondary coil; a resin insulating material filled in the ignition coil; and a first cushioning member covering both axial corners of the central core portion. Engine ignition coil. 2. An ignition coil for an internal combustion engine according to claim 1, wherein a second cushioning member is provided on at least one of both ends in the axial direction of said central core portion. 3. The first cushioning member is formed in a bag shape, and a hole having a diameter smaller than the diameter of the central core portion is provided in at least one of both axial ends of the central core portion. The ignition coil for an internal combustion engine according to claim 1 or 2, wherein: 4. The ignition coil for an internal combustion engine according to claim 1, wherein the first buffer member comprises a plurality of members. 5. The ignition coil for an internal combustion engine according to claim 1, wherein said central core portion and said first cushioning member are integrally formed. 6. The ignition coil for an internal combustion engine according to claim 5, wherein said first buffer member is made of an elastomer resin. 7. The ignition coil for an internal combustion engine according to claim 5, wherein said first buffer member is made of a heat-shrinkable tube. 8. The ignition coil for an internal combustion engine according to claim 1, wherein the first cushioning member covers the entire surface of the central core portion. 9. The ignition coil for an internal combustion engine according to claim 1, wherein an end corner of the central core portion is chamfered. 10. An ignition coil for an internal combustion engine that generates a high voltage to be applied to an ignition device for an internal combustion engine, wherein the rod-shaped core body or at least one of both ends in the axial direction of the rod-shaped core body and the core body. A primary core and a secondary spool disposed on the outer periphery of the central core, a primary coil wound around the primary spool, and the secondary spool. A wound secondary coil, comprising: a resin insulating material filled in the ignition coil; one of the two corners in the axial direction of the central core part faces a space, and the other of the two corners Is an ignition coil for an internal combustion engine, which faces a space or is covered by a first cushioning member. 11. The ignition coil for an internal combustion engine according to claim 10, wherein a second cushioning member is provided on at least one of both ends in the axial direction of said central core portion. 12. The second cushioning member is disposed between an axial end face of the central core where an end corner facing a space is located, and a case member surrounding an outer periphery of the central core. 12. The ignition coil for an internal combustion engine according to claim 11, wherein the ignition coil is sealed.