JP2013115076A - Ignition coil for internal combustion engine - Google Patents

Abstract

An ignition coil for an internal combustion engine capable of simplifying a process of electrically connecting an iron core and a conductive bush.
In the manufacturing process of an ignition coil 100, first, a coil case 110 in which a conductive bush 120 and a relay conductor 150 are insert-molded is prepared, and a coil assembly 130 is incorporated therein. At this time, the coil assembly 130 is incorporated into the case, and at the same time, the iron core terminal 135 and the internal terminal 155 are electrically connected. That is, since the conductive member that conducts the conductive bush 120 and the iron core terminal 135 is integrated into the coil case or the coil assembly, a separate component mounting step for electrically connecting the iron core and the conductive bush is unnecessary. Thus, the method for manufacturing the ignition coil is simplified.
[Selection] Figure 8

Description

  The present invention relates to an ignition coil for an internal combustion engine, and is particularly suitable for use in stabilizing the potential of an iron core.

  2. Description of the Related Art In recent years, ignition coils that are attached to an internal combustion engine are widely used, such as a “pen-shaped coil” that houses a coil portion in a plug hole, and a “rectangular coil” that houses a coil assembly in a case head. Among these, in order to reduce the size and weight of the rectangular coil, a small rectangular coil in which the outer peripheral iron core is accommodated in the coil case has been studied.

  Japanese Patent Application Laid-Open No. 2009-299614 (Patent Document 1) introduces an example of the above-described small rectangular coil. Such an ignition coil accommodates a side iron core (outer peripheral iron core in the claims) in an outer case (coil case in the claims), and the outer case includes an insert conductor (the conductive bush in the claims). ) Provided with a mounting arm (flange portion in the claims). The insert conductor is provided with a conduction terminal extending from itself, and the conduction terminal is insert-molded so as to be exposed in the outer case. And a side iron core exposes a part of protective cover which coat | covers this, and is connected to the conduction | electrical_connection terminal of the said insert conductor via the V-shaped metal plate of another component.

  In the ignition coil of Patent Document 1, the iron core and the insert conductor are brought into conduction with such a configuration, and the iron core is brought to the same potential as the engine ground by bringing the insert conductor into contact with the engine block. As described above, in the ignition coil according to Patent Document 1, since the iron core is grounded, the potential fluctuation of the iron core is suppressed, and insulation breakdown around the iron core, noise radiation, and the like are suppressed.

JP2009-299614

  However, according to the ignition coil according to Patent Document 1, the metal plate that electrically couples the side iron core and the insert conductor is a separate component. For this reason, if the metal plate is not mounted in a preferable state, a contact failure between the metal plate and the side iron core occurs, causing a problem that the side iron core and the metal plate cannot be electrically coupled. In such a situation, the iron core can no longer be electrically coupled to the insert conductor, so that the iron core potential cannot be grounded.

  In addition, a sufficient biasing force may not be obtained with a V-shaped metal plate. For this reason, if impurities are deposited on the contact portion with the metal plate, the contact portion has a large contact resistance, and the iron core potential may not be effectively grounded.

  Further, in Patent Document 1, since a separate metal plate is used, a step of accommodating a coil assembly including an iron core in an exterior case, and a step of arranging and mounting the metal plate so as to make the side iron core and the insert conductor conductive. (Installation process) is required. In such a mounting process, the metal plate must be arranged with high accuracy due to its nature, and the cost for maintaining a certain quality increases. In addition, in order to simplify the manufacturing process, it is preferable to eliminate as many redundant causes as possible, such as a mounting process for separate parts.

  In view of the above problems, the present invention ensures electrical connection between the iron core and a terminal (iron core terminal) that is electrically connected to the conductive bush, and at the same time, simplifies the process of electrically connecting the iron core and the conductive bush. It is an object of the present invention to provide an ignition coil for an internal combustion engine that can be made into an engine.

  In order to solve the above problems, the present invention has the following configuration of an ignition coil for an internal combustion engine. That is, a central core around which a primary coil and a secondary coil are wound, an outer peripheral core that forms a closed magnetic path together with the central core, a coil case that accommodates both the central core and the outer peripheral core, and the coil A flange portion integrally formed with the case, an iron core terminal fixed to at least one of the central core and the outer peripheral iron core and in contact with and electrically connected to the both iron cores; And a conductive bush electrically connected to the iron core terminal.

  Preferably, the central axis of the central core forms a substantially parallel positional relationship with a case symmetry axis connecting the flange portion and the centroid of the coil case, and the iron core terminal has the case symmetry axis. It shall be arranged on the flange side.

  Preferably, the iron core terminal is fixed by a protective cover for the iron core. More preferably, in the portion of the iron core terminal embedded in the protective cover, an iron core abutting portion that abuts any one of the iron cores, and a protruding portion that is formed to protrude from the back surface of the iron core abutting portion. It will be arranged. Here, it is more preferable that a convex portion is formed in the iron core contact portion.

  Preferably, the iron core terminal is fixed by a protective cover of the outer peripheral iron core. Here, the iron core terminal is electrically connected at the first abutting portion at the abutting position with the central iron core and at the second abutting portion at the abutting position with the outer peripheral core. It is preferable that the contact part exists.

  More preferably, only the second contact portion is embedded in the protective cover. Here, it is further preferable that a convex portion is formed on the back surface of the first contact portion.

  According to the ignition coil for an internal combustion engine according to the present invention, since the iron core terminal is directly contacted and fixed to the surface of the iron core, the electrical coupling between the iron core and the iron core terminal is reliably ensured. Further, since the iron core terminal is integrated with the iron core assembly, the process of mounting the iron core terminal in the coil case is not required, and the manufacturing process for electrically connecting the iron core and the conductive bush is simplified.

The figure which shows the structure of the ignition coil for internal combustion engines. The figure explaining the case symmetry axis of a coil case. The figure which shows the structure of the iron core assembly which concerns on embodiment. The figure which shows the structure of the iron core terminal which concerns on embodiment. The figure which shows the manufacturing method of the outer periphery iron core which concerns on this Embodiment. The assembly figure of the outer periphery iron core which concerns on this Embodiment. The figure which shows the structure of a relay terminal. FIG. 6 illustrates a main part of an embodiment. The figure explaining the axial center direction of a center iron core. The figure which shows the structure of the iron core terminal which concerns on other embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1A shows an external view of an ignition coil for an internal combustion engine. In the ignition coil 100 for an internal combustion engine according to the present embodiment, a coil assembly is accommodated in a coil case 110. The ignition coil described in this embodiment belongs to a small rectangular coil.

The coil case 110 is made of a thermoplastic resin such as PPS or PBT, and the housing portion 111, the connector portion 112, the output portion 113, and the flange portion 114 are integrally molded. The accommodating portion 111 has a shell state having an opening on one side, and when the coil assembly is accommodated, the gap is impregnated with a thermosetting resin such as an epoxy resin. The connector 112 has a plurality of terminals (a power supply terminal, a signal terminal, a ground terminal, etc.) arranged therein, and these terminals and an ECU (Engine
Control Unit) is electrically connected.

  The output unit 113 is accommodated in a plug hole of the engine block together with a high-pressure tower (not shown). The output terminal 113 has a high voltage terminal disposed therein, and the high voltage terminal is applied with a high voltage (several kV) from the coil assembly on the one hand, and is electrically connected to the spark plug on the other hand.

  The flange portion 114 has a tongue-like shape, is formed on one side surface of the housing portion 111, and has the conductive bush 120 embedded and fixed at a predetermined location. Since the conductive bush 120 is required to have both electrical conductivity and structural strength, it is preferable to use a steel material (stainless steel, sulfur-cut steel, etc.). The conductive bush 120 is formed in a cylindrical body, and the inner diameter portion is used as a bolt through hole. The internal combustion engine ignition coil 100 (hereinafter abbreviated as an ignition coil) has a high-pressure tower inserted into a plug hole, and a fixing bolt is screwed into a female screw portion of the engine block, whereby the ignition coil is connected to the engine block. The high-voltage terminal is fixed and electrically connected to the spark plug.

  FIG. 2A shows a state where the coil case is observed from the opening side. In describing the figure, a plane in which the coil case is observed from the opening side, that is, a plane orthogonal to the central axis of the plug hole is defined as a vertical observation plane. This vertical observation surface is set at an arbitrary position of the central axis in a range where the flange portion 114 and the connector portion 112 are projected.

  Referring to FIG. 2A, when the coil case 110 is viewed with respect to the vertical observation surface, the coil case 110 has a flange portion 114 disposed on one surface of the accommodating portion 111, and a connector portion on the opposite surface. It is recognized that 112 is arranged. Further, in FIG. 4, a case symmetry axis AXc is given to the coil case 110. The case symmetry axis AXc passes through the centroid G (or center of gravity) of the entire coil case, and the figure divided by the case symmetry axis AXc is substantially line symmetric. Since the case symmetry axis AXc is a boundary line between both symmetrical figures, the centroid (or the center of gravity) of the flange portion 114 and the centroid G of the entire coil case are connected. Hereinafter, of the case symmetry axis AXc, the orientation in which the flange portion 114 is formed is referred to as a flange side Ff, and the orientation in which the connector portion 112 is formed is referred to as a connector side Fc.

  Since the bolt fixing position differs depending on the engine block, the conductive bush 120 may need to be eccentric in the coil case 110. In such a case, the shape of the coil case 110 is such that the flange portion 114 is asymmetrical as shown in FIG. However, the case symmetry axis AXc in this case also passes through the centroid G of the entire coil case and also passes through the centroid of the flange portion 114. Thus, the case symmetry axis AXc means a reference line that makes the shapes on both sides thereof substantially symmetrical.

  Returning to FIG. 1, the description of the ignition coil will be continued. The coil assembly functions as a transformer, and is composed of a core assembly 130 including a central core and an outer peripheral core, a primary coil wound around the central core (not shown), and coaxially wound around the primary coil. It is comprised from the secondary coil 140, the insulating protective cover coat | covered on the surface of the iron core, and the insulating spool which accommodates the wire wire of a coil. As shown in FIG. 1 (b), the coil assembly is stored in the accommodating portion 111 of the coil case 110, and in addition, an igniter (not shown) or the like is appropriately accommodated. These gaps are filled with epoxy resin, and the occurrence of leakage current at the site where high voltage is generated is suppressed. In the present embodiment, a part of the outer peripheral core is not slightly impregnated with the epoxy resin, but the outer peripheral core is not exposed to the outside because it is covered with the protective cover.

  In the ignition coil 100 having such a configuration, when an ignition signal is received from the ECU, a high voltage is generated from the coil assembly at an appropriate timing based on the ignition signal, and the high voltage is applied to the high voltage terminal. In the spark plug, such a high voltage is applied, and the air-fuel mixture is combusted in accordance with the piston cycle.

  FIG. 3 shows the structure of the iron core assembly. As shown in FIG. 3A, the iron core assembly 130 includes an outer peripheral iron core 131, a protective cover 132 covering the outer iron core 131, a central iron core 133, a protective cover (not shown) covering the core, a magnet 134, An iron core terminal 135 is included. The protective cover for the central iron core is not shown for the sake of convenience.

  The central iron core 133 and the outer peripheral iron core 131 are formed by laminating soft magnetic materials such as silicon steel plates. In the present embodiment, the outer peripheral iron core 131 is C-shaped, and ends 131a and 131b are formed at both ends thereof. The outer peripheral iron core 131 is covered with a protective cover 132 so that the end 131a and the end 131b are exposed. Further, an iron core terminal 135 is in direct contact with the side surface of the outer peripheral iron core 131 and is fixed by a protective cover 132. In addition, the protective cover coat | covered by each iron core is shape | molded by thermoplastic resins, such as PBT, and this resin material has high electrical insulation performance.

  The iron core terminal 135 is made of a conductive material and plays a role of being electrically connected to the conductive bush as will be described later. The iron core terminal 135 is preferably bonded and fixed in contact with the iron core in order to ensure an electrical conduction state. For this reason, in this Embodiment, the electrical connection is ensured by making the iron core terminal 135 contact an iron core, and making it adhere with a protective cover so that the contact state may be maintained.

  In particular, the iron core terminal 135 is preferably fixed by a protective cover of the outer iron core 131. This is because the connecting portion (131a, 131b, 133a, 133b) between the outer peripheral iron core 131 and the central iron core 133 has a small dimensional margin for fixing and fixing the iron core terminal 135 on the central iron core side. On the other hand, in the present embodiment, since the outer peripheral iron core 131 has a curved shape, the core terminal 135 is fixed to the outer peripheral iron core side by utilizing the dimensional merit based on the shape. In particular, when the outer peripheral iron core 131 is C-shaped, it is easy to form a terminal arrangement space on the outer peripheral iron core side.

  On the other hand, the center iron core 133 has a substantially I shape, and end portions 133a and 133b are appropriately formed in accordance with the end shape of the outer peripheral iron core 131. Further, a protective cover for the central core (not shown) is covered so as to expose the end portions 133a and 133b.

  When combining the central iron core 133 and the outer peripheral iron core 131, the iron cores sandwich the magnet 134 at the end portions (131b, 133b) and directly contact at the end portions (131a, 133a). In this way, the iron core assembly 130 is combined and a closed magnetic circuit is formed by both iron cores (see FIG. 2b). In addition, in the center iron core 133 of the iron core assembly 130, a primary coil and a secondary coil are provided coaxially (not shown).

  Here, referring to FIG. 2B, the iron core terminal 135 abuts on the surface of the central iron core 133 and the surface of the outer peripheral iron core 131, and electrical connection is performed at each abutting portion. I understand. More specifically, first, the iron core terminal 135 is fixed to the outer peripheral iron core 131, so that a contact portion (second contact portion) between the iron core terminal 135 and the outer peripheral iron core 131 is formed. When the center core 133 and the outer peripheral core 131 are combined, the tip of the core terminal 135 is brought into contact with the tail end surface of the center core 133 (first contact portion), whereby the core terminal 135 and the center core 133 are The first contact portion is formed.

  As described above, the iron core assembly 130 must be divided into two or more parts to form a coil portion on one iron core side, and then the outer peripheral iron core must be combined. Therefore, it is inevitable that contact portions (131a, 131b, 133a, 133b) between the iron cores are formed. And, since the electrical resistance increases at such a contact boundary surface, even if the terminal is brought into contact with only one iron core and the terminal is grounded, it is in direct contact with the grounding terminal. If there is no iron core, the excited voltage cannot be grounded instantly, which causes problems of noise and leakage current.

  On the other hand, in this embodiment, since the terminals are in direct contact with both the central iron core 133 and the outer peripheral iron core 131, it becomes possible to instantaneously ground both iron core potentials, and there is a problem such as noise or leakage current. Can be avoided.

  Next, an iron core terminal used in the present embodiment will be described with reference to FIG. Note that FIG. 4A is a diagram observed from the surface that contacts the iron core (core contact surface), and FIG. 4B is a diagram that is observed from the back surface of the core contact surface. The iron core terminal 135 is formed from a plate-like body made of a conductive material, and is pressed as shown. The core terminal 135 is required to have both electrical conductivity and elasticity, and it is preferable to use, for example, stainless steel or titanium. The shape of the iron core terminal 135 includes a main surface portion 135a, a projecting portion 135b, a step portion 135c, and convex portions 135e and 135d formed in the step portion 135c.

  Among these, each of the main surface part 135a or the step part 135c corresponds to an iron core contact part where a part or all of the main surface part 135a or the step part 135c contacts the iron core. The main surface portion 135a has a protruding portion 135b formed in a curved shape, and the protruding portion 135b is disposed so as to protrude toward the back surface of the iron core contact surface. In the protruding portion 135b, the apex height of the protruding portion is adjusted according to the thickness of the protective cover 132 of the iron core.

  In the step portion 135c, the height of the step at the iron core terminal is determined according to the step shape of the contact portion between the iron cores. In the step portion 135c, a convex portion 135d is formed so as to protrude from the iron core abutting surface, and a convex portion 135e is formed so as to protrude from the back surface of the iron core abutting surface. Accordingly, the convex portion 135d is brought into contact with the iron core, and the convex portion 135e is brought into contact with an internal terminal provided in the case. These convex portions are provided to increase the contact pressure and ensure electrical connection. Therefore, it may be a convex part with a point contact shape, but in this embodiment, in order to efficiently secure the conduction cross-sectional area, the shape of the convex part is striped and is in line contact at the conduction point. I am doing so. Such a convex portion may be formed on the main surface body 135a. Further, it is preferable that the contact portion of the iron core and the iron core terminal is soldered. By doing in this way, a conduction cross section is ensured and it becomes possible to reduce contact resistance.

  Next, with reference to FIG. 5, the coating method of the outer periphery iron core 131 is demonstrated. In Fig.5 (a), the outline Sp of metal mold | die MTm is shown by the thick line. That is, in the groove portion of the mold MTm, the thickness of the protective cover is offset from the surface of the outer peripheral iron core. Moreover, the said groove | channel is suitably formed with the outline Sp so that a clearance gap may not arise in the edge part of an outer periphery iron core, and the level | step-difference part of an iron core terminal. In the protective cover coating step, the outer peripheral iron core 131 and the iron core terminal 135 are set according to the shape of the mold groove. At this time, the iron core terminal 135 is sandwiched between the side surface of the outer peripheral iron core 135 and the contour Sp of the mold because the apex height of the protruding portion 135b is adjusted to the thickness of the protective cover. For this reason, the outer periphery iron core 135 will be hold | maintained in the desired position which should be arrange | positioned. When the parts are set in this way, a melted and liquefied thermoplastic resin is injected from an injection hole (not shown), and the outer peripheral iron core coated with the resin is completed by cooling it (see FIG. 5b).

  In the present embodiment, as shown in FIG. 5B, a portion (first contact portion) that is in contact with the central iron core 133 is exposed from the protective cover 132 and is in contact with the outer peripheral iron core 131 ( The second contact part) is covered with a protective cover. For this reason, the iron core terminal 135 exhibits a so-called cantilever support structure because the vicinity of the point where the protective cover is interrupted becomes the fixed end.

  The iron core terminal 135 generates a reaction force in a direction opposite to the external force by the cantilever support structure and the elastic performance. That is, when the central iron core 133 is pressed against the iron core contact surface of the stepped portion 135c, the iron core terminal 135 generates a reaction force in the direction of the central iron core 133. Therefore, the contact state with the central iron core 133 is suitable. . In the present embodiment, the dimension of the central iron core 133 is determined so that the stepped portion 135c is mutated in the back surface direction of the iron core contact surface. Therefore, when the central iron core 133 is combined with the outer peripheral iron core 131 as shown in FIG. 6A, a reaction force in the direction of the iron core contact surface is generated, and the terminal and the central iron core 133 are reliably brought into contact with each other. Become.

  The central iron core 133 is covered with a protective cover 136 as shown in FIG. Then, when this is combined with the outer peripheral iron core 131, as shown in FIG. 6B, the exposed portion of each iron core is covered with the protective cover while only a part of the iron core terminal 135 is exposed.

  As described above, according to the ignition coil 100 according to the present embodiment, the iron core terminal 135 is integrated into the iron core assembly 130 so that the iron core terminal 135 reliably contacts the iron core. And by connecting this iron core terminal 135 and the internal terminal of a coil case, the electrical connection (electrical coupling) with an iron core and the electroconductive bush 120 will be performed reliably.

  FIG. 7A shows an example of a relay conductor that electrically connects the iron core terminal and the conductive bush. The relay conductor 150 is made of a conductive material such as stainless steel or titanium, and is formed by bending a plate-like body of the conductive material. More specifically, the relay terminal 150 is provided on the middle of the relay conductor with curved gripping portions 151a and 151b, a space 152 formed between both ends of the gripping portions 151a and 151a. The narrowed portions 153a and 153b, the trunk portions 154a and 154b connected to the narrowed portions 153a and 153b, and the internal terminal 155 connected to both the trunk portions 154a and 154b are formed.

  As shown in FIG. 7B, the relay conductor 150 is insert-molded in the coil case 110 with the conductive bush 120 sandwiched therebetween. However, only the internal terminal 155 is exposed in the case. The layout position of the end surface 155s of the internal terminal is appropriately devised so as to contact the exposed surface of the iron core terminal 135. More preferably, the mutual dimensional tolerances are set so that the positional relationship between the contact surface on the iron core terminal side and the contact surface on the internal terminal side is “an interference fit”. As a result, the contact area between the iron core terminal 135 and the internal terminal 155 is elastically or plastically deformed to increase the contact area, so that the electrical resistance at the contact section can be reduced. Further, since the contact pressure is large at the contact portion between the iron core terminal 135 and the internal terminal 155, the impurity layer at the contact portion is destroyed, and the electrical resistance at the contact interface is reduced. Furthermore, since contact pressure is always generated at the contact portion between the iron core terminal 135 and the internal terminal 155, an electrical contact failure does not occur. In this embodiment, since the relay terminal is cut out from an inexpensive face material, the contact surface 155s of the internal terminal is in a flat state without a step. For this reason, the electrical connection state of the internal terminal 155 and the iron core terminal 135 is optimized by forming the convex part 135e in the iron core terminal 135.

  FIG. 8 shows the periphery of the relay conductor of the ignition coil according to the present embodiment. In the manufacturing process of the ignition coil 100, first, a coil case 110 in which the conductive bush 120 and the relay conductor 150 are insert-molded is prepared, and the coil assembly 130 is incorporated therein. At this time, the coil assembly 130 is incorporated into the case, and at the same time, the iron core terminal 135 and the internal terminal 155 are electrically connected. However, the iron core and the conductive bush 120 are electrically coupled.

  That is, according to the method of manufacturing an ignition coil according to the present embodiment, the conductive member that conducts the conductive bush 120 and the iron core terminal 135 is integrated into the coil case or the coil assembly. A separate component mounting step for electrically connecting the two is eliminated, and the method of manufacturing the ignition coil is simplified. In addition, in the ignition coil according to the present embodiment, since the electrical connection between the iron core and the conductive bushing is reliably performed, it becomes possible to efficiently mass-produce products that have cleared the quality standards for performance. This will contribute to cost reduction.

  FIG. 9 shows a state in which the ignition coil is observed from the vertical observation surface. Of these, FIG. 9 (a) relates to Patent Document 1, and FIG. 9 (b) relates to the present embodiment. is there. The central axis AXm refers to the longitudinal direction of the central iron core 133, and the case symmetry axis AXc is a virtual reference axis formed by connecting the flange portion 114 and the centroid G of the case.

  As shown in FIG. 9A, the central iron core 133 according to Patent Document 1 is arranged such that the central axis AXm is perpendicular to the case symmetry axis AXc. In such a case, the connection portion C between the central iron core 133 and the outer peripheral iron core 131 is away from the case symmetry axis AXc, and as a result is also away from the conductive bush 120. In particular, when the outer peripheral iron core 131 is disposed between the flange portion 114 and the central iron core 133, this distance is further increased.

  Since the iron core terminal 135 according to the present embodiment is electrically connected to both the central iron core 133 and the outer peripheral iron core 131, it is originally preferable to arrange the iron core terminal 135 in the vicinity of the connecting portion C. However, according to the ignition coil according to Patent Document 1, if the iron core terminal 135 is disposed in the vicinity of the connection portion C, the iron core terminal is moved away from the conductive bush 120, so that the relay for conducting the conductive bush 120 is conducted. The structure of the member is complicated.

  On the other hand, in the ignition coil 100 according to the present embodiment, the central axis AXm of the iron core is substantially parallel to the case symmetry axis AXc. The iron core terminal 135 is disposed on the flange side Ff of the case symmetry axis AXc. For this reason, the iron core terminal 135 dramatically approaches the conductive bush 120 in a state of being arranged in the vicinity of the connection portion C. For this reason, the structure of the relay conductor 150 that connects the conductive bush 120 and the iron core terminal 135 can be simplified and miniaturized. In particular, the distance between the conductive bush 120 and the iron core terminal 135 is further reduced by bringing the central axis AXm of the iron core closer to the case symmetry axis AXc. For this reason, the iron core terminal 135 and the relay conductor 150 can be easily connected only by exposing the internal terminal 155 as described above in the case.

  In addition, an iron core terminal is not limited to the form mentioned above, It is possible to change into various forms based on the thought of this invention. Explaining an example thereof, as shown in FIG. 10A, an iron core terminal 200 according to the modified example includes a body portion 201, an outer peripheral core contact portion 201, a leg portion 203, and a central core contact portion 205. , Is press-molded from the face material. The leg part 203 has a shape that straddles the opening part 204, and a central iron core contact part 205 is provided at the end part thereof.

  FIG. 10B shows an ignition coil when the iron core terminal 200 is applied. The coil case 110 is not shown for convenience. As illustrated, the conductive bush 120 is connected to the relay conductor 150 at the lower end. The relay conductor 150 passes through the opening 204 of the iron core terminal 200 and is fixed so as to be in direct contact with the central iron core 133. On the other hand, the core terminal 200 is arranged so that the outer peripheral core contact portion 202 stands upright, and the portion 202 contacts the side surface of the outer peripheral core 131. Further, the center core contact portion 205 is press-fitted into a groove provided in the protective cover at the bottom of the center core, and the contact portion 205 is in contact with the bottom surface of the center core.

  In such an embodiment, the protective cover is formed on the iron core by a molding method, and then the iron core terminal 200 is attached to complete the iron core assembly 130. In this case, in the protective cover coating step, the step of arranging the terminal components is not required, and therefore the step can be simplified. The core terminal 200 is integrated with the core assembly 130 by being fitted into the groove portion of the protective cover. That is, at this time, the iron core terminal 200 comes into contact with both iron cores. Then, by incorporating the iron core assembly 130 into the coil case 110, the bottom portion of the central iron core 133 and the relay conductor 150 are connected, whereby the iron core and the conductive bush 120 are electrically coupled. At this time, since the iron core terminal and the conductive bush are electrically connected via any one of the iron cores, even if an interface resistance is formed at the connecting portion between the iron cores, the potential excited by both iron cores is It becomes possible to make it instantly ground.

  As described above, even in such a modified example, since the technical idea of the present invention is applied, the electrical connection between the iron core and the conductive bush is surely performed, and the work process for performing the electrical connection is performed. Simplification is achieved.

  DESCRIPTION OF SYMBOLS 100 Ignition coil for internal combustion engines, 110 Coil case, 111 Accommodating part, 112 Connector, 113 Output part, 114 Bulge part, 120 Conductive bushing, 130 Iron core assembly, 131 Outer iron core, 132 Protective cover, 133 Central iron core, 136 Protective cover , 135b projecting part, 135c first contact part, 135a second contact part, 135e convex part, 135d convex part.

Claims (9)

  A central core around which a primary coil and a secondary coil are wound, an outer peripheral core that forms a closed magnetic path together with the central core, a coil case that accommodates both the central core and the outer peripheral core, and the coil case An integrally molded flange portion, an iron core terminal fixed to at least one of the central iron core and the outer peripheral iron core and in contact with and electrically connected to both iron cores, and the iron core terminal provided on the flange portion An ignition coil for an internal combustion engine, comprising: a conductive bush electrically connected to the internal combustion engine. The central axis of the central iron core is formed by forming a substantially parallel positional relationship with a case symmetry axis connecting the flange portion and the centroid of the coil case,
2. The ignition coil for an internal combustion engine according to claim 1, wherein the iron core terminal is disposed on a flange side of the case symmetry axis.   The ignition coil for an internal combustion engine according to claim 1 or 2, wherein the iron core terminal is fixed by a protective cover for the iron core.   Of the iron core terminal, a portion embedded in the protective cover is provided with an iron core abutting portion that abuts on any iron core and a protruding portion that protrudes from the back surface of the iron core abutting portion. The ignition coil for an internal combustion engine according to any one of claims 1 to 3.   The ignition coil for an internal combustion engine according to claim 4, wherein a convex portion is formed at the iron core contact portion.   6. The ignition coil for an internal combustion engine according to claim 1, wherein the iron core terminal is fixed by a protective cover of the outer peripheral iron core.   The iron core terminal includes a first contact portion electrically connected at a contact position with the central iron core, and a second contact portion electrically connected at a contact position with the outer peripheral core. The ignition coil for an internal combustion engine according to any one of claims 1 to 6, wherein:   The ignition coil for an internal combustion engine according to claim 7, wherein only the second contact portion is embedded in the protective cover.   The ignition coil for an internal combustion engine according to claim 7 or 8, wherein a convex portion is formed on a back surface of the first contact portion.

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