JP2007311716A - Ignition coil and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition coil and a method of manufacturing the same which can effectively reduce air bubbles remaining in thermosetting resin charged into the ignition coil. <P>SOLUTION: An ignition coil 1 includes a primary coil 21; a secondary coil 22; a magnetic component 4 forming a magnetic circuit of the primary coil 21; a resin component 31 supporting the magnetic component 4; and a stress relaxing member 51 which is disposed between the magnetic component 4 and the resin component 31 in the magnetization direction of the magnetic component 4, and relaxes a stress generated between the magnetic component 4 and the resin component 31. The ignition coil 1 is formed by charging the thermosetting resin 11 into a gap in a case 3 for storing the primary coil 21, the secondary coil 22, the magnetic component 4, and the stress relaxing member 51. The stress relaxing member 51 is made of a foam material including a number of closed cells, and a rubber material having a gas transmission rate equal to or higher than that of natural rubber. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ignition coil used for generating a spark from a spark plug in an internal combustion engine and a method for manufacturing the same.

In an internal combustion engine such as a gasoline vehicle that travels using gasoline as fuel, a spark plug is used to ignite combustion in each cylinder. An ignition coil including a primary coil and a secondary coil is used to generate a high-voltage spark discharge between a pair of electrodes in the spark plug.
In this ignition coil, a magnetic part is used which passes a magnetic field generated when a current is passed through the primary coil and forms an induced magnetic field in a direction opposite to the magnetic field passing direction when the current is interrupted. .

  It is known that when shrinkage stress is applied in the magnetization direction of the magnetic component, the magnetization performance is deteriorated due to the influence of magnetostriction. Therefore, in order to relieve the contraction stress, a stress relieving member is disposed in the magnetization direction of the magnetic component between the magnetic component and the resin component that supports the magnetic component. As the stress relieving member, a silicone foam which has few additives and is easy to manage is used.

Each gap in the ignition coil is filled with a thermosetting resin such as an epoxy resin in order to fix and insulate each component. The filling of the thermosetting resin is performed by setting the gap in the ignition coil in a vacuum state, injecting a liquid thermosetting resin in the vacuum state, and then curing the injected thermosetting resin. ing.
By the way, when the filling failure of the thermosetting resin occurs in the ignition coil, the gap due to the filling failure may cause the generation of cracks or the leakage of high voltage current in the secondary coil. . Therefore, a contrivance is made to eliminate the factor that hinders the injection property of the thermosetting resin.

  For example, in the ignition coil disclosed in Patent Document 1, the upper elastic member is disposed in the vertical direction on the upper elastic member disposed above the central core made of a rod-like magnetic body that is inserted and disposed on the inner peripheral side of the primary coil and the secondary coil. A void removal passage penetrating through is formed. According to this, when filling the ignition coil with epoxy resin, the voids existing in the gap between the central core and the elastic tube covering the outer periphery of the central core are relatively removed via the void removal passage. Can be easily removed.

  However, it has been found that bubbles are generated in the liquid thermosetting resin no matter how much evacuation is performed when the liquid thermosetting resin is injected. When the cause of the bubble generation was investigated, it was found that the silicone foam used as the stress relaxation member generated bubbles.

JP 2004-22582 A

  The present invention has been made in view of such conventional problems, and provides an ignition coil capable of effectively suppressing bubbles remaining in the thermosetting resin filled in the ignition coil and a method for manufacturing the same. It is something to try.

The first invention provides a primary coil and a secondary coil, a magnetic component that forms a magnetic circuit by the primary coil, a resin component that supports the magnetic component, and the magnetic component between the magnetic component and the resin component. A stress relieving member disposed in the magnetization direction of the component to relieve stress generated between the magnetic component and the resin component, the primary coil, the secondary coil, the magnetic component, and the stress relieving member In the ignition coil formed by filling the gap in the case containing the thermosetting resin,
The stress relaxation member is an ignition coil that is made of a foam material having closed cells and a gas material having a gas permeability equal to or lower than that of natural rubber.

In the ignition coil according to the present invention, the stress relaxation member arranged in the magnetization direction of the magnetic component is devised between the magnetic component and the resin component.
That is, the stress relaxation member of the present invention is made of a foam having closed cells and a rubber material having a gas permeability equal to or lower than that of natural rubber.
Thus, the primary coil, the secondary coil, the magnetic component, and the stress relieving member are disposed in the case, and the gap formed in the case is evacuated, and in the vacuum state, the liquid state is heated in the gap. When injecting the curable resin, it is possible to suppress the gas in the closed cells in the stress relaxation member from being transmitted to the outside of the stress relaxation member and to prevent the gas from remaining in the thermosetting resin. it can.

  The reason why the generation of gas can be suppressed is that the gas permeability is equal to or less than that of natural rubber even though the rubber material constituting the stress relaxation member of the present invention is formed from a foam having closed cells. I think it depends. Therefore, when the inside of the case is evacuated, it is effective that gases such as air, carbon dioxide, and nitrogen permeate the stress relaxation member from the closed cells in the stress relaxation member and are generated in the thermosetting resin. I think it can be suppressed.

  Therefore, according to the ignition coil of the present invention, it is possible to effectively suppress the gas from remaining as bubbles in the thermosetting resin filled in the ignition coil. Thereby, it can suppress effectively that a crack generate | occur | produces in a thermosetting resin, and can improve the insulation performance of a thermosetting resin.

The second invention provides a primary coil and a secondary coil, a magnetic component that forms a magnetic circuit by the primary coil, a resin component that supports the magnetic component, and the magnetic component between the magnetic component and the resin component. A stress relieving member disposed in the magnetization direction of the component to relieve stress generated between the magnetic component and the resin component, the primary coil, the secondary coil, the magnetic component, and the stress relieving member In the ignition coil formed by filling the gap in the case containing the thermosetting resin,
The stress relaxation member is an ignition coil that is made of a foam of a rubber material having closed cells and has a skin layer formed at the time of rubber molding on the entire outer peripheral surface thereof. ).

Also in the ignition coil of the present invention, the stress relaxation member arranged in the magnetization direction of the magnetic component is devised between the magnetic component and the resin component.
That is, the stress relaxation member of the present invention is made of a foam of a rubber material having closed cells, and has a skin layer that is a hardened surface layer formed at the time of rubber molding on the entire outer peripheral surface thereof.
Thus, the primary coil, the secondary coil, the magnetic component, and the stress relieving member are disposed in the case, and the gap formed in the case is evacuated, and in the vacuum state, the liquid state is heated in the gap. When injecting the curable resin, it is possible to suppress the gas in the closed cells in the stress relaxation member from being transmitted to the outside of the stress relaxation member and to prevent the gas from remaining in the thermosetting resin. it can.

  The reason why the generation of this gas can be suppressed is that the rubber material constituting the stress relaxation member of the present invention is formed of a foam having closed cells, but has the skin layer on the entire outer peripheral surface thereof. It depends on. Therefore, when the inside of the case is evacuated, it is effective that gases such as air, carbon dioxide, and nitrogen permeate the stress relaxation member from the closed cells in the stress relaxation member and are generated in the thermosetting resin. I think it can be suppressed.

  Therefore, according to the ignition coil of the present invention, it is possible to effectively suppress the gas from remaining as bubbles in the thermosetting resin filled in the ignition coil. Thereby, it can suppress that a crack generate | occur | produces in a thermosetting resin, and can improve the insulation performance of a thermosetting resin.

According to a third aspect of the present invention, there is provided a primary coil and a secondary coil, a magnetic component that forms a magnetic circuit by the primary coil, a resin component that supports the magnetic component, and the magnetic component between the magnetic component and the resin component. A stress relieving member disposed in the magnetization direction of the component to relieve stress generated between the magnetic component and the resin component, the primary coil, the secondary coil, the magnetic component, and the stress relieving member In the ignition coil formed by filling the gap in the case containing the thermosetting resin,
The stress relaxation member is formed of a rubber material foam having closed cells and has a gas barrier coating layer on the entire outer peripheral surface thereof.

Also in the ignition coil of the present invention, the stress relaxation member arranged in the magnetization direction of the magnetic component is devised between the magnetic component and the resin component.
That is, the stress relaxation member of the present invention is made of a foam of a rubber material having closed cells and has a gas barrier coating layer on the entire outer peripheral surface thereof.
Thus, the primary coil, the secondary coil, the magnetic component, and the stress relieving member are disposed in the case, and the gap formed in the case is evacuated, and in the vacuum state, the liquid state is heated in the gap. When injecting the curable resin, it is possible to suppress the gas in the closed cells in the stress relaxation member from being transmitted to the outside of the stress relaxation member and to prevent the gas from remaining in the thermosetting resin. it can.

  The reason why the generation of gas can be suppressed is that the gas barrier coating layer is formed on the entire outer peripheral surface of the rubber material constituting the stress relaxation member of the present invention even though the rubber material is formed from a foam having closed cells. By having Therefore, when the inside of the case is evacuated, it is effective that gases such as air, carbon dioxide, and nitrogen permeate the stress relaxation member from the closed cells in the stress relaxation member and are generated in the thermosetting resin. I think it can be suppressed.

  Therefore, the ignition coil of the present invention can also effectively suppress the gas from remaining as bubbles in the thermosetting resin filled in the ignition coil. Thereby, it can suppress that a crack generate | occur | produces in a thermosetting resin, and can improve the insulation performance of a thermosetting resin.

According to a fourth aspect of the present invention, a primary coil and a secondary coil, a magnetic component that forms a magnetic circuit by the primary coil, a resin component that supports the magnetic component, and the magnetic component between the magnetic component and the resin component. A stress relieving member disposed in the magnetization direction of the component to relieve stress generated between the magnetic component and the resin component, the primary coil, the secondary coil, the magnetic component, and the stress relieving member In a method of manufacturing an ignition coil formed by filling a gap in a case containing a thermosetting resin,
An arrangement step of arranging the primary coil, the secondary coil, the magnetic component, and the stress relaxation member in the case;
An injecting step in which a gap in the case formed by the arrangement is in a vacuum state, and a thermosetting resin in a liquid state is injected into the gap in the vacuum state;
When performing the curing step of curing the thermosetting resin after the injection,
In the ignition coil manufacturing method, the stress relaxation member is made of a foam having closed cells and has a gas permeability equal to or lower than that of natural rubber.

In the ignition coil manufacturing method of the present invention, when the ignition coil is manufactured by performing the placement step, the injection step, and the curing step, the stress relaxation member is made of a foam having closed cells, and has a gas permeability. A rubber member equal to or less than natural rubber is used.
Thereby, in the arrangement step, the primary coil, the secondary coil, the magnetic component, and the stress relaxation member are arranged in the case. In the injection step, the gap formed in the case is evacuated, and in this vacuum state When injecting a liquid thermosetting resin into the gap, the gas in the closed cells in the stress relaxation member is prevented from permeating out of the stress relaxation member, and this gas remains in the thermosetting resin. Can be suppressed. The reason why the generation of this gas can be suppressed is considered in the same manner as in the first invention.

  Therefore, according to the ignition coil manufacturing method of the present invention, it is possible to effectively suppress the gas from remaining as bubbles in the thermosetting resin filled in the ignition coil. Thereby, it can suppress effectively that a crack generate | occur | produces in a thermosetting resin, and can improve the insulation performance of a thermosetting resin.

According to a fifth aspect of the present invention, there is provided a primary coil and a secondary coil, a magnetic component that forms a magnetic circuit by the primary coil, a resin component that supports the magnetic component, and the magnetic component between the magnetic component and the resin component. A stress relieving member disposed in the magnetization direction of the component to relieve stress generated between the magnetic component and the resin component, the primary coil, the secondary coil, the magnetic component, and the stress relieving member In a method of manufacturing an ignition coil formed by filling a gap in a case containing a thermosetting resin,
An arrangement step of arranging the primary coil, the secondary coil, the magnetic component, and the stress relaxation member in the case;
An injecting step in which a gap in the case formed by the arrangement is in a vacuum state, and a thermosetting resin in a liquid state is injected into the gap in the vacuum state;
When performing the curing step of curing the thermosetting resin after the injection,
The stress relaxation member is a method for producing an ignition coil, comprising a rubber member made of a foam having closed cells and having a skin layer formed at the time of rubber molding on the entire outer peripheral surface thereof. 8).

In the method for manufacturing an ignition coil according to the present invention, when the ignition coil is manufactured by performing the placement step, the injection step, and the curing step, the stress relaxation member is made of a foam having closed cells and the entire outer peripheral surface thereof. A rubber member having the above skin layer is used.
Thereby, in the arrangement step, the primary coil, the secondary coil, the magnetic component, and the stress relaxation member are arranged in the case. In the injection step, the gap formed in the case is evacuated, and in this vacuum state When injecting a liquid thermosetting resin into the gap, the gas in the closed cells in the stress relaxation member is prevented from permeating out of the stress relaxation member, and this gas remains in the thermosetting resin. Can be suppressed. The reason why the generation of gas can be suppressed is considered in the same manner as in the second invention.

  Therefore, according to the ignition coil manufacturing method of the present invention, it is possible to effectively suppress the gas from remaining as bubbles in the thermosetting resin filled in the ignition coil. Thereby, it can suppress that a crack generate | occur | produces in a thermosetting resin, and can improve the insulation performance of a thermosetting resin.

According to a sixth aspect of the invention, there is provided a primary coil and a secondary coil, a magnetic component that forms a magnetic circuit using the primary coil, a resin component that supports the magnetic component, and the magnetic component between the magnetic component and the resin component. A stress relieving member disposed in the magnetization direction of the component to relieve stress generated between the magnetic component and the resin component, the primary coil, the secondary coil, the magnetic component, and the stress relieving member In a method of manufacturing an ignition coil formed by filling a gap in a case containing a thermosetting resin,
An arrangement step of arranging the primary coil, the secondary coil, the magnetic component, and the stress relaxation member in the case;
An injecting step in which a gap in the case formed by the arrangement is in a vacuum state, and a thermosetting resin in a liquid state is injected into the gap in the vacuum state;
When performing the curing step of curing the thermosetting resin after the injection,
In the method of manufacturing an ignition coil, the stress relaxation member is made of a foam having closed cells, and a rubber member having a gas barrier coating layer on the entire outer peripheral surface thereof is used.

In the method for manufacturing an ignition coil according to the present invention, when the ignition coil is manufactured by performing the placement step, the injection step, and the curing step, the stress relaxation member is made of a foam having closed cells and the entire outer peripheral surface thereof. A rubber member having the above skin layer is used.
Thereby, in the arrangement step, the primary coil, the secondary coil, the magnetic component, and the stress relaxation member are arranged in the case. In the injection step, the gap formed in the case is evacuated, and in this vacuum state When injecting a liquid thermosetting resin into the gap, the gas in the closed cells in the stress relaxation member is prevented from permeating out of the stress relaxation member, and this gas remains in the thermosetting resin. Can be suppressed. The reason why the generation of gas can be suppressed is considered in the same manner as in the third invention.

  Therefore, also by the manufacturing method of the ignition coil of the present invention, it is possible to effectively suppress the gas from remaining as bubbles in the thermosetting resin filled in the ignition coil. Thereby, it can suppress that a crack generate | occur | produces in a thermosetting resin, and can improve the insulation performance of a thermosetting resin.

A preferred embodiment in the first to sixth inventions described above will be described.
In the first and fourth inventions, the stress relaxation member is made of one or more blends of natural rubber (NR), chloroprene rubber (CR), ethylene propylene rubber (EPDM), and nitrile rubber (NBR). It is preferable to constitute (claims 2 and 7).
In these cases, it is possible to easily select a rubber material (rubber member) that is practical and easy and has a gas permeability equal to or lower than that of natural rubber.

In the first to sixth aspects of the invention, the stress relaxation member is connected to an axial end surface of a central core made of a magnetic material inserted and arranged on the inner peripheral side of the primary coil and the secondary coil. Preferred (claims 5 and 10).
In these cases, the stress relaxation member can suppress the contraction stress from being applied in the axial direction that is the magnetization direction of the central core.
Further, the stress relaxation member can be connected only to one axial end face of the central core, or can be connected to both axial end faces of the central core.

Embodiments of the ignition coil and the manufacturing method thereof according to the present invention will be described below with reference to the drawings.
Example 1
As shown in FIG. 1, the ignition coil 1 of this example supports a primary coil 21 and a secondary coil 22, a magnetic component (a central core described later) 4 that forms a magnetic circuit by the primary coil 21, and the magnetic component 4. The resin component (igniter case portion to be described later) 31 is arranged between the magnetic component 4 and the resin component 31 in the magnetization direction of the magnetic component 4 to relieve the stress generated between the magnetic component 4 and the resin component 31. The stress relaxation member 51 to be used.
The ignition coil 1 is formed by filling the gap in the case 3 that houses the primary coil 21, the secondary coil 22, the magnetic component 4, and the stress relaxation member 51 with the thermosetting resin 11. The stress relaxation member 51 of the present example is made of a foam having a large number of closed cells 511 and made of a rubber material having a gas permeability equal to or lower than that of natural rubber.

Hereinafter, the ignition coil 1 of this example will be described in detail with reference to FIGS.
The ignition coil 1 of this example is of a stick type that is used by inserting and arranging a cylindrical portion including a primary coil 21 and a secondary coil 22 in a plug hole in an engine (cylinder head).
As shown in FIG. 1, the magnetic component 4 of the present example includes a central core 4 made of a magnetic material disposed on the inner peripheral side of the primary coil 21 and the secondary coil 22, and outer peripheral sides of the primary coil 21 and the secondary coil 22. It consists of the outer periphery core 23 which consists of the arrange | positioned magnetic body. The central core 4 has a substantially circular cross section, and the outer core 23 has a circular cross section.

The stress relaxation member 51 (see FIG. 2) made of a foam having the closed cells 511 is connected to one axial end surface 41 of the central core 4. A cushion member 52 made of a rubber material is disposed on the other axial end surface 42 of the central core 4. The stress relaxation member 51 of this example is made of a foam of ethylene propylene rubber having a large number of closed cells 511, and the cushion member 52 of this example is made of a solid material of silicone rubber.
A stress relief tape 45 is wound around the outer periphery of the central core 4, and each axial end portion of the tape 45 is an axially outer end surface of the stress relaxation member 51 or an axially outer end surface of the cushion member 52. Each is folded.

Further, the stress relaxation member 51 is inserted into the aligning portion 314 formed in the igniter base portion 31, and the central core 4 and the rubber are inserted into the secondary spool 221. The stress relaxation member 51 relaxes the stress generated between the axial end surface 41 of the center core 4 and the igniter base portion 31 when the ignition coil 1 is used, and the axis that is the magnetization direction of the center core 4 The contraction stress generated in the direction L is relieved.
Further, since the stress relaxation member 51 includes a large number of closed cells 511, high cushion performance (rebound resilience) can be obtained.
In addition, a cushion body 53 made of a rubber material is disposed on the other axial end surface of the outer peripheral core 23 between the plug base portion 33 described later.

  Moreover, the stress relaxation member 51 of this example has a columnar shape, and is formed by cutting out a part of a foam original plate having a large number of closed cells formed in a plate shape. When the foam original plate is molded, a skin layer 513, which is a hardened surface layer formed by resin molding, is formed on the entire outer peripheral surface thereof. This foam base plate can be molded by mixing a vulcanizing agent and a foaming agent in a rubber compound and foaming during heating and vulcanization by extrusion molding or injection molding.

  Further, as shown in FIG. 2, the stress relaxation member 51 has skin layers 513 on both end surfaces in the axial direction L of the columnar shape, while the cutout is formed on the outer peripheral surface of the side portion in the columnar shape. The broken bubble 512 formed when performing is formed. As will be described later, when the thermosetting resin 11 is injected into the case 3 in a vacuum state, the gas in the closed cells 511 of the stress relaxation member 51 passes through the outer peripheral surface of the side portion. It is easy to penetrate to the outside.

  Further, as shown in FIG. 1, the primary coil 21 is formed by winding a primary wire with insulation coating around the outer peripheral surface of a primary spool 211 made of a cylindrical resin, and the secondary coil 22 is formed of a cylindrical resin. A secondary electric wire covered with insulation is wound around the outer peripheral surface of the secondary spool 221 having a larger number of turns than the primary electric wire. The secondary coil 22 is disposed on the inner peripheral side of the primary coil 21, and the central core 4 is disposed on the inner peripheral side of the secondary coil 22. The primary coil 21 is disposed in the case 3 made of a cylindrical resin, and an outer peripheral core 23 is disposed on the inner peripheral side of the case 3. The primary spool 211 and the secondary spool 221 are made of a thermoplastic resin.

  The central core 4 is formed by laminating a plurality of flat electromagnetic steel plates (silicon steel plates in this example) provided with an insulating coating in a cross-sectional direction orthogonal to the axial direction L of the ignition coil 1. The outer peripheral core 23 is formed by laminating a plurality of cylindrical electromagnetic steel plates (silicon steel plates in this example) formed with slits (gap) in the axial direction L via an adhesive in the radial direction. The central core 4 and the outer core 23 can form a magnetic path through which the magnetic flux generated by flowing current through the primary coil 21 and the magnetic flux generated by the secondary coil 22 pass.

As shown in FIG. 1, the ignition coil 1 of this example is provided with an igniter 311 for supplying power to the primary coil 21 at one end in the axial direction L, and at the other end in the axial direction L. Is provided with a plug cap 331 for attaching a spark plug.
The case 3 in this example includes a plug base 331 provided with a plug cap 331, a secondary terminal (high voltage terminal) 332, a spring 333, the primary coil 21, the secondary coil 22, the central core 4, the outer core 23, and the like. And the igniter base portion 31 on which the igniter 311 is disposed. Each component 31-33 of case 3 consists of thermoplastic resins.

  Although illustration is omitted, the spark plug is inserted and disposed in the plug cap 331 with its terminal portion in contact with the spring 333. As shown in FIG. 1, the igniter base portion 31 is formed with a connector portion 312 formed by insert molding the conductive pin 313 in the igniter 311. The coil case part 32 is formed with a flange part 321 for attaching the ignition coil 1 to the engine.

The thermosetting resin 11 is continuously filled in the case 3 surrounded by the plug base portion 33, the coil case portion 32, and the igniter base portion 31.
The igniter 311 includes a power control circuit that uses a switching element that operates in response to a signal from an ECU (engine control unit), an ion current detection circuit that detects an ion current, and the like.

  As shown in FIG. 1, the thermosetting resin 11 is formed in the case 3, that is, between the tape 455 and the secondary spool 221 on the outer periphery of the central core 4, and the gap between the secondary windings constituting the secondary coil 22, The space between the secondary coil 22 and the primary spool 211, the space between the primary windings constituting the primary coil 21, the space between the primary coil 21 and the outer core 23, and the space between the outer core 23 and the case 3 are filled. ing. The thermosetting resin 11 in this example is made of an epoxy resin.

  In the ignition coil 1, when a pulse-like spark generation signal is transmitted from the ECU to the igniter 311, the power control circuit in the igniter 311 operates, a current flows through the primary coil 21, and the central core 4 and the outer core 23 are connected. A passing magnetic field is formed. And when the electric current which flows into the primary coil 21 is interrupted | blocked, the induction magnetic field which passes the center core 4 and the outer periphery core 23 is formed toward the direction opposite to the formation direction of the said magnetic field. By forming this induced magnetic field, an induced electromotive force (back electromotive force) is generated in the secondary coil 22, and a spark can be generated from the spark plug attached to the ignition coil 1.

Next, the method for manufacturing the ignition coil 1 will be described, and the effects of the ignition coil 1 of this example and the manufacturing method thereof will be described.
In the manufacturing method of the ignition coil 1 of this example, the following arrangement | positioning process, injection | pouring process, and hardening process are performed, and the ignition coil 1 using the said stress relaxation member 51 is manufactured.
When the ignition coil 1 is manufactured, as shown in FIG. 3, first, as an arranging step, the tape 45 is wound around the plug base portion 33 and the coil case portion 32, the central core 4, the stress relaxation member 51, and the cushion member. 52, the central core body 52, the primary coil 21 wound around the primary spool 211, the secondary coil 22 wound around the secondary spool 221, the outer peripheral core 23, the cushion body 53, the secondary terminal 332, and the like are arranged. Then, the case 3 is formed by attaching the igniter case 3 portion provided with the igniter to the coil case portion 32, and the centering portion 314 positions the center core 4 and the secondary spool 221 at the center.

Next, as shown in the figure, as an injection process, the gap 301 in the case 3 formed by the arrangement of the components is evacuated, and in this vacuum state, the thermosetting resin 11 in a liquid state is placed in the gap 301. Inject. At this time, it is possible to suppress the gas in the closed cells 511 in the stress relaxation member 51 from being transmitted to the outside of the stress relaxation member 51, and to prevent the gas from remaining in the thermosetting resin 11.
The reason why the generation of gas can be suppressed is that the gas permeability is equal to or less than that of natural rubber even though the rubber material constituting the stress relaxation member 51 of the present example is formed from a foam having closed cells 511. I think that it is because. Therefore, when the inside of the case 3 is evacuated, air, carbon dioxide, nitrogen, or the like passes through the stress relaxation member 51 as a gas from the closed cells 511 in the stress relaxation member 51 and enters the thermosetting resin 11. I think that it can control effectively.

Thereafter, after the injection of the thermosetting resin 11 is finished, the ignition coil 1 is manufactured by curing the injected thermosetting resin 11 as a curing step.
Therefore, according to the ignition coil 1 of this example and the manufacturing method thereof, it is possible to effectively suppress the gas from remaining as bubbles in the thermosetting resin 11 filled in the ignition coil 1. Thereby, generation | occurrence | production of a crack in the thermosetting resin 11 can be suppressed effectively, and the insulation performance of the thermosetting resin 11 can be improved.

FIG. 4 shows the gas of silicone rubber (Q), natural rubber (NR), and various rubbers (EPDM, SBR, CR, IIR, 39% NBR) having a gas permeability equivalent to or lower than that of natural rubber. The bar graph which compared the transmittance | permeability is shown. The figure shows the gas permeability (%) of silicone rubber and other rubbers when the gas permeability (gas permeability coefficient) of natural rubber is 100 (%).
As can be seen from the figure, the gas permeability of silicone rubber is significantly higher than that of natural rubber, whereas the gas permeability of other rubbers is equal to or lower than that of natural rubber. Therefore, when silicone rubber is used as the stress relaxation member 51, bubbles may be formed in the thermosetting resin 11, whereas when natural rubber or other rubber is used as the stress relaxation member 51, thermosetting is performed. It can be seen that the formation of bubbles in the conductive resin 11 can be effectively suppressed.

(Example 2)
In this example, as shown in FIG. 5, the stress relaxation member 51A is made of a foam of a rubber material having closed cells 511, and a skin layer 513 which is a hardened surface layer formed on the entire outer peripheral surface during rubber molding. It is an example using the rubber member which has. The rubber member in this example is made of silicone rubber.
As shown in FIG. 6, the stress relaxation member 51 </ b> A of this example can be provided with a skin layer 513 on the entire outer peripheral surface by molding one by one in a pair of molds 7.

In this example, since the skin layer 513 is formed on the entire outer peripheral surface of the stress relaxation member 51A, the case of the above vacuum state is used even though silicone rubber having a high gas permeability is used for the stress relaxation member 51A. When the thermosetting resin 11 is injected into the thermosetting resin 11, the stress relaxing member 51 is transmitted through the closed cells 511 in the stress relaxing member 51 </ b> A to prevent gas from being generated in the thermosetting resin 11. be able to.
Also in this example, other configurations are the same as those of the first embodiment, and the same effects as those of the first embodiment can be obtained.

(Example 3)
In this example, as shown in FIG. 7, the stress relaxation member 51B is made of a rubber material foam having closed cells 511 and a rubber member having a gas barrier coating layer 514 on the entire outer peripheral surface thereof. It is. The rubber member of this example is made of silicone rubber, and the gas barrier coating layer 514 of this example is made of polyacrylonitrile (PAN).

In this example, the coating layer 514 is formed on the entire outer peripheral surface of the stress relaxation member 51B, so that the stress relaxation member 51 is made of silicone rubber having a high gas permeability, but the above vacuum case. When the thermosetting resin 11 is injected into the thermosetting resin 11, gas is prevented from being generated in the thermosetting resin 11 through the stress relaxing member 51 from the closed cells 511 in the stress relaxing member 51 </ b> B. be able to.
Also in this example, other configurations are the same as those of the first embodiment, and the same effects as those of the first embodiment can be obtained.

Sectional explanatory drawing which shows the ignition coil in Example 1. FIG. Sectional explanatory drawing which shows the stress relaxation member in Example 1. FIG. Sectional explanatory drawing which shows the state which inject | pours thermosetting resin in the case of an ignition coil in Example 1. FIG. The bar graph which shows the comparison of the gas permeability of various rubber | gum of the gas permeability which is equivalent to a silicone rubber, natural rubber, and natural rubber in Example 1, or lower than natural rubber. Sectional explanatory drawing which shows the stress relaxation member in Example 2. FIG. Sectional explanatory drawing which shows the shaping | molding die which shape | molds the stress relaxation member in Example 2. FIG. Sectional explanatory drawing which shows the stress relaxation member in Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition coil 11 Thermosetting resin 21 Primary coil 22 Secondary coil 3 Case 31 Igniter base part (resin component)
32 Coil case part 33 Plug base part 4 Central core (magnetic part)
51 Stress Relieving Member 511 Closed Cell 513 Skin Layer 514 Coating Layer L Axial Direction

Claims (10)

Arranged in the magnetization direction of the magnetic component between the magnetic component and the resin component between the primary component and the secondary coil, the magnetic component that forms the magnetic circuit by the primary coil, the resin component that supports the magnetic component, and the magnetic component and the resin component And a stress relaxation member that relieves stress generated between the magnetic component and the resin component, and in the case that houses the primary coil, the secondary coil, the magnetic component, and the stress relaxation member. In the ignition coil formed by filling the gap with a thermosetting resin,
The stress relaxation member is made of a foam having closed cells and made of a rubber material having a gas permeability equal to or lower than that of natural rubber.   2. The ignition coil according to claim 1, wherein the stress relaxation member is made of one or more blends of natural rubber, chloroprene rubber, ethylene propylene rubber, and nitrile rubber. Arranged in the magnetization direction of the magnetic component between the magnetic component and the resin component between the primary component and the secondary coil, the magnetic component that forms the magnetic circuit by the primary coil, the resin component that supports the magnetic component, and the magnetic component and the resin component And a stress relaxation member that relieves stress generated between the magnetic component and the resin component, and in the case that houses the primary coil, the secondary coil, the magnetic component, and the stress relaxation member. In the ignition coil formed by filling the gap with a thermosetting resin,
The above-mentioned stress relaxation member is made of a foam of a rubber material having closed cells, and has a skin layer formed at the time of rubber molding on the entire outer peripheral surface thereof. Arranged in the magnetization direction of the magnetic component between the magnetic component and the resin component between the primary component and the secondary coil, the magnetic component that forms the magnetic circuit by the primary coil, the resin component that supports the magnetic component, and the magnetic component and the resin component And a stress relaxation member that relieves stress generated between the magnetic component and the resin component, and in the case that houses the primary coil, the secondary coil, the magnetic component, and the stress relaxation member. In the ignition coil formed by filling the gap with a thermosetting resin,
The above-mentioned stress relaxation member is made of a foam of a rubber material having closed cells, and has a gas barrier coating layer on the entire outer peripheral surface thereof.   5. The stress relaxation member according to claim 1, wherein the stress relaxation member is connected to an axial end surface of a central core made of a magnetic body that is inserted and arranged on the inner peripheral side of the primary coil and the secondary coil. Features an ignition coil. Arranged in the magnetization direction of the magnetic component between the magnetic component and the resin component between the primary component and the secondary coil, the magnetic component that forms the magnetic circuit by the primary coil, the resin component that supports the magnetic component, and the magnetic component and the resin component And a stress relaxation member that relieves stress generated between the magnetic component and the resin component, and in the case that houses the primary coil, the secondary coil, the magnetic component, and the stress relaxation member. In the method of manufacturing an ignition coil formed by filling the gap with a thermosetting resin,
An arrangement step of arranging the primary coil, the secondary coil, the magnetic component, and the stress relaxation member in the case;
An injecting step in which a gap in the case formed by the arrangement is in a vacuum state, and a thermosetting resin in a liquid state is injected into the gap in the vacuum state;
When performing the curing step of curing the thermosetting resin after the injection,
A method for producing an ignition coil, characterized in that a rubber member made of a foam having closed cells and having a gas permeability equal to or lower than that of natural rubber is used as the stress relaxation member.   7. The method for manufacturing an ignition coil according to claim 6, wherein the stress relaxation member is made of one or more blends of natural rubber, chloroprene rubber, ethylene propylene rubber, and nitrile rubber. Arranged in the magnetization direction of the magnetic component between the magnetic component and the resin component between the primary component and the secondary coil, the magnetic component that forms the magnetic circuit by the primary coil, the resin component that supports the magnetic component, and the magnetic component and the resin component And a stress relaxation member that relieves stress generated between the magnetic component and the resin component, and in the case that houses the primary coil, the secondary coil, the magnetic component, and the stress relaxation member. In the method of manufacturing an ignition coil formed by filling the gap with a thermosetting resin,
An arrangement step of arranging the primary coil, the secondary coil, the magnetic component, and the stress relaxation member in the case;
An injecting step in which a gap in the case formed by the arrangement is in a vacuum state, and a thermosetting resin in a liquid state is injected into the gap in the vacuum state;
When performing the curing step of curing the thermosetting resin after the injection,
A method for producing an ignition coil, characterized in that a rubber member made of a foam having closed cells and having a skin layer formed at the time of rubber molding is used as the stress relaxation member. Arranged in the magnetization direction of the magnetic component between the magnetic component and the resin component between the primary component and the secondary coil, the magnetic component that forms the magnetic circuit by the primary coil, the resin component that supports the magnetic component, and the magnetic component and the resin component And a stress relaxation member that relieves stress generated between the magnetic component and the resin component, and in the case that houses the primary coil, the secondary coil, the magnetic component, and the stress relaxation member. In the method of manufacturing an ignition coil formed by filling the gap with a thermosetting resin,
An arrangement step of arranging the primary coil, the secondary coil, the magnetic component, and the stress relaxation member in the case;
An injecting step in which a gap in the case formed by the arrangement is in a vacuum state, and a thermosetting resin in a liquid state is injected into the gap in the vacuum state;
When performing the curing step of curing the thermosetting resin after the injection,
A method for producing an ignition coil, characterized in that a rubber member made of a foam having closed cells and having a gas barrier coating layer on the entire outer peripheral surface thereof is used as the stress relaxation member.   The stress relaxation member according to any one of claims 6 to 9, wherein the stress relaxation member is connected to an axial end surface of a central core made of a magnetic body that is inserted and arranged on the inner peripheral side of the primary coil and the secondary coil. A method of manufacturing an ignition coil characterized by the above.

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