Ignition coil for internal combustion engine

Abstract

An ignition coil includes a primary coil, a secondary coil, a center core, an outer core, an igniter, a coil case, and an electrically insulating fixing resin. On an inner surface of the coil case on a bottom side in an installation direction, a case side rib is formed that protrudes from the inner surface of the coil case to an axial high pressure side. The case side rib has a tapered shape such that the amount of protrusion of the case side rib to the axial high pressure side increases toward the bottom side along the installation direction. The case side rib is arranged to abut a corner of the igniter on the bottom side in the installation direction and on an axial low pressure side, thereby pressing the igniter against the outer core.

Description

Technical Field

[0001] This disclosure relates to ignition coils for internal combustion engines. Background Technology

[0002] In an internal combustion engine, an ignition coil is used to ignite the air-fuel mixture within the combustion chamber. An ignition coil typically includes a primary coil, a secondary coil, an igniter, a center core, and an outer core. The secondary coil is positioned outside and coaxial with the primary coil to ensure magnetic coupling. The igniter includes a switching element for selectively enabling and disabling power to the primary coil. A center core and an outer core are provided to allow the magnetic flux generated by the primary and secondary coils to flow through them.

[0003] During operation, the heat generated by the switching elements raises the temperature of the igniter. Therefore, efforts are made to cool the igniter in order to keep its temperature within its heat-resistant range. For example, Japanese Patent Application Publication No. JP 2009-188364 A discloses an ignition coil in which: the igniter is arranged in a coil housing, facing the outer core, with a gap formed between them; the gap between the igniter and the outer core is filled with resin for electrical insulation and fixation. Furthermore, a heat sink is provided on the outer core side of the igniter circuit board. With this configuration, the heat generated by the igniter switching elements can be dissipated to the outer core through the heat sink and resin, thereby suppressing the rise in igniter temperature. Summary of the Invention

[0004] In recent years, with the tightening of exhaust and fuel economy regulations, there has been a requirement to increase the output of the ignition coil. Furthermore, the output of the ignition coil can be increased, for example, by increasing the current when the power supply to the primary coil is interrupted by the ignition switch element. However, in this case, the electrical energy consumed by the ignition switch element increases; therefore, it is necessary to further improve the cooling of the ignition coil.

[0005] In the ignition coils disclosed in the aforementioned patent documents, a gap is intentionally provided between the igniter and the outer core, and this gap is filled with resin for electrical insulation and fixation. However, when the gap between the igniter and the outer core is large, it may be difficult to effectively dissipate the heat generated by the igniter switching element to the outer core.

[0006] In view of the above-mentioned problems, this disclosure was made. Therefore, the main object of this disclosure is to provide an ignition coil for an internal combustion engine that can effectively dissipate the heat generated by the ignition switch element to the outer core.

[0007] According to this disclosure, a first ignition coil for an internal combustion engine is provided. The first ignition coil includes a primary coil, a secondary coil, a center core, an outer core, an igniter, a coil housing, and an electrically insulating fixing resin. The primary coil is configured to be powered. The secondary coil is disposed outside the primary coil and coaxial with it. The secondary coil is configured to generate an induced electromotive force when the power supply to the primary coil is interrupted. The center core is disposed within the primary coil. The outer core is a four-sided annular ring, with its four portions located on opposite sides of the secondary coil in the axial direction and on opposite sides of the secondary coil in the width direction perpendicular to the axial direction. The outer core and the center core together form a closed magnetic circuit in the ignition coil. The igniter includes a switching element configured to selectively enable and interrupt the power supply to the primary coil. The igniter is arranged adjacent to the outer core on the low-voltage side in the axial direction. The coil housing has an opening on one side in the mounting direction and a bottom on the other side in the mounting direction; the mounting direction is perpendicular to both the axial and width directions. The coil housing internally receives all the primary coil, secondary coil, center core, outer core, and igniter. Electrically insulating resin is filled into the space within the coil housing to secure the primary coil, secondary coil, center core, outer core, and igniter within the coil housing, while simultaneously insulating them from each other. Furthermore, on the inner surface of the coil housing on the bottom side in the mounting direction, housing side ribs are formed, protruding axially towards the high-voltage side; the high-voltage side is opposite in axial direction to the low-voltage side. The housing side ribs have a tapered shape, such that the amount of protrusion of the housing side ribs towards the axial high-voltage side increases towards the bottom side along the mounting direction. The housing side ribs are arranged to abut against the corners of the igniter on the bottom side in the mounting direction and the axial low-voltage side, thereby pressing the igniter against the outer core.

[0008] With the above-described configuration of the first ignition coil, when the igniter is placed into the coil housing (the outer core, etc., are already placed inside the coil housing), the corners of the igniter abut against the side ribs of the housing. At this time, the igniter shifts towards the outer core via the side ribs of the housing. Therefore, the igniter can be appropriately pressed against the outer core. Thus, heat can be effectively dissipated from the igniter to the outer core.

[0009] According to this disclosure, a second ignition coil for an internal combustion engine is also provided. The second ignition coil includes a primary coil, a secondary coil, a center core, an outer core, an igniter, a coil housing, a connector, and an electrically insulating fixing resin. The primary coil is configured to be powered. The secondary coil is disposed outside the primary coil and coaxial with it. The secondary coil is configured to generate an induced electromotive force when the power supply to the primary coil is interrupted. The center core is disposed within the primary coil. The outer core is a four-sided annular ring, with its four portions located on opposite sides of the secondary coil in the axial direction and on opposite sides of the secondary coil in the width direction perpendicular to the axial direction. The outer core and the center core together form a closed magnetic circuit in the ignition coil. The igniter includes a switching element configured to selectively enable and interrupt the power supply to the primary coil. The igniter is arranged adjacent to the outer core on the low-voltage side of the outer core in the axial direction. The coil housing has an opening on one side in the mounting direction and a bottom on the other side in the mounting direction; the mounting direction is perpendicular to both the axial and width directions. The coil housing internally receives all the primary coil, secondary coil, center core, outer core, and igniter. A connector is mounted on the coil housing to extend outside the coil housing. The connector has a connecting wall that forms part of the coil housing on the axial low-voltage side. Electrically insulating resin is filled into the space within the coil housing to secure the primary coil, secondary coil, center core, outer core, and igniter within the coil housing while electrically insulating them from each other. Furthermore, connector side ribs are formed on the inner surface of the connecting wall, protruding from the inner surface towards the axial high-voltage side; the high-voltage side is opposite to the low-voltage side axially. The connector side ribs have a tapered portion that tapers such that the amount of the tapered portion protruding from the inner surface of the connector wall towards the axial high-voltage side increases along the mounting direction towards the open side. The connector side ribs are used to press the igniter against the outer core.

[0010] Using the above-described configuration of the second ignition coil, when the igniter is assembled into the coil assembly (where the primary coil, secondary coil, center core, and outer core are already assembled), or when the connector is installed into the coil housing (where the igniter, outer core, etc., are already assembled), the igniter abuts against the tapered portion of the connector's side rib. At this time, the igniter shifts towards the outer core through the tapered portion of the connector's side rib. Therefore, the igniter can be appropriately pressed against the outer core. Thus, heat can be effectively dissipated from the igniter to the outer core. Attached Figure Description

[0011] Figure 1 This is a cross-sectional view of the ignition coil perpendicular to the width direction according to the first embodiment.

[0012] Figure 2 It is a cross-sectional view perpendicular to the width direction before the coil assembly is placed in the coil housing, the coil assembly and the coil housing together forming part of the ignition coil according to the first embodiment.

[0013] Figure 3 This is a cross-sectional view of the ignition coil according to the first embodiment, perpendicular to the axial direction, before the space in the coil housing is filled with electrically insulating fixing resin.

[0014] Figure 4 yes Figure 1 The image shows an enlarged view of the portion forming the side ribs of the coil housing.

[0015] Figure 5 This is a perspective view showing the side ribs of the housing.

[0016] Figure 6 This is a schematic diagram of the side ribs of the shell along the axial direction.

[0017] Figure 7 This is an explanatory diagram showing the coil assembly placed inside the coil housing.

[0018] Figure 8 This is a perspective view showing the formation of multiple housing side ribs in the coil housing according to a modification of the first embodiment.

[0019] Figure 9 This is an enlarged cross-sectional view of a portion of the ignition coil according to the second embodiment, perpendicular to the width direction.

[0020] Figure 10 This is a schematic diagram showing the axial direction of the connector side ribs formed in the connector of the ignition coil according to the second embodiment.

[0021] Figure 11 This is an explanatory diagram showing the igniter assembled into a spool molding body, the igniter and the spool molding body together forming part of the ignition coil according to the second embodiment.

[0022] Figure 12 This is an enlarged cross-sectional view of a portion of the modified ignition coil according to the second embodiment, perpendicular to the width direction.

[0023] Figure 13 This is an enlarged cross-sectional view of a portion of the ignition coil according to the third embodiment, perpendicular to the width direction.

[0024] Figure 14 This is an explanatory diagram showing the connector assembled into the coil housing, the connector and the coil housing together forming part of the ignition coil according to the third embodiment.

[0025] Figure 15 This is an enlarged cross-sectional view of a portion of the first ignition coil according to the fourth embodiment, perpendicular to the width direction.

[0026] Figure 16 This is an enlarged cross-sectional view of a portion of the second ignition coil according to the fourth embodiment, perpendicular to the width direction.

[0027] Figure 17 This is an enlarged cross-sectional view of a portion of the third ignition coil according to the fourth embodiment, perpendicular to the width direction.

[0028] Figure 18 This is an enlarged cross-sectional view of a portion of the fourth ignition coil according to the fourth embodiment, perpendicular to the width direction.

[0029] Figure 19 This is an enlarged cross-sectional view of a portion of the fifth ignition coil according to the fourth embodiment, perpendicular to the width direction.

[0030] Figure 20 This is an enlarged cross-sectional view of a portion of the sixth ignition coil according to the fourth embodiment, perpendicular to the width direction.

[0031] Figure 21 This is an enlarged cross-sectional view of a portion of the seventh ignition coil according to the fourth embodiment, perpendicular to the width direction.

[0032] Figure 22 This is an enlarged cross-sectional view of a portion of the eighth ignition coil according to the fourth embodiment, perpendicular to the width direction.

[0033] Figure 23 This is an enlarged cross-sectional view of a portion of the ninth ignition coil according to the fourth embodiment, perpendicular to the mounting direction.

[0034] Figure 24 This is an enlarged cross-sectional view of a portion of the tenth ignition coil according to the fourth embodiment, perpendicular to the axial direction. Detailed Implementation

[0035] Exemplary embodiments will now be described with reference to the accompanying drawings. It should be noted that, for clarity and ease of understanding, the same reference numerals will be used in the drawings for the same components that have the same function throughout the specification, and descriptions of the same components will not be repeated to avoid redundancy.

[0036] [First Embodiment]

[0037] like Figure 1-3 As shown, the ignition coil 1 for an internal combustion engine according to the first embodiment includes a primary coil 2, a secondary coil 3, a center core 41, an outer core 42, an igniter 43, a coil housing 5, and an electrically insulating fixing resin (or a resin for electrical insulation and fixing) 6.

[0038] also, Figure 1 The image shows the ignition coil 1 in a state where the electrically insulating fixing resin 6 has been filled into the space within the coil housing 5, while Figure 3 The ignition coil 1 is shown before the space in the coil housing 5 is filled with the electrically insulating fixing resin 6.

[0039] The primary coil 2 is configured to be powered; the power supply to the primary coil 2 is selectively enabled and interrupted by a switching element. The secondary coil 3 is disposed outside the primary coil 2 and coaxial with it. The secondary coil 3 is configured to generate an induced electromotive force when the power supply to the primary coil 2 is interrupted. The central core 41 is disposed inside the primary coil 2. The outer core 42 is a four-sided ring, with its four parts located along the axial direction L of the ignition coil 1 of the secondary coil 3 (see...). Figure 1 On the opposite sides L1 and L2, and the secondary coil 3 along the width direction W (perpendicular to the axial direction L) of the ignition coil 1 (see... Figure 3 On the opposite side of the ignition coil 1. The central core 41 and the outer core 42 together form a closed magnetic circuit.

[0040] Igniter 43 includes a switching element. For example... Figure 1 As shown, the igniter 43 is arranged adjacent to the outer core 42 on the low-voltage side L2 along the axial direction L. The coil housing 5 has an opening 52 on one side of the ignition coil 1 in the mounting direction D (which is perpendicular to the axial direction L and the width direction W), and a bottom 53 on the other side of the mounting direction D. The coil housing 5 is configured to receive all the primary coil 2, secondary coil 3, center core 41, outer core 42, and igniter 43 therein. Electrically insulating fixing resin 6 is filled into the space in the coil housing 5 to fix the primary coil 2, secondary coil 3, center core 41, outer core 42, and igniter 43 in the coil housing 5 while electrically insulating them from each other.

[0041] like Figure 4 As shown, a housing side rib 54 is formed on the inner surface of the coil housing 5 on the bottom side D1 (i.e., the side where the bottom 53 of the coil housing 5 is located) in the mounting direction D. The housing side rib 54 extends from the inner surface of the coil housing 5 toward the high-voltage side L1 in the axial direction L. Furthermore, the housing side rib 54 has a tapered shape, such that the amount of protrusion of the housing side rib 54 toward the high-voltage side L1 in the axial direction L increases along the mounting direction D toward the bottom side D1. In addition, the housing side rib 54 is arranged to abut against the corners of the igniter 43 on the bottom side D1 in the mounting direction D and the low-voltage side L2 in the axial direction L, thereby pressing the igniter 43 against the outer core 42.

[0042] Next, the configuration of the ignition coil 1 according to this embodiment will be described in detail.

[0043] (Ignition coil 1)

[0044] like Figure 1 As shown, the ignition coil 1 is designed to be mounted on the cylinder head cover 7 of the vehicle's internal combustion engine and to cause the spark plug (not shown) arranged in the cylinder head to generate a spark discharge in the combustion chamber of the internal combustion engine.

[0045] The ignition coil 1 includes a coil body 11 and a connector 12. The coil body 11 consists of a primary coil 2, a secondary coil 3, an igniter 43, a coil housing 5, etc. The connector 12 extends from the coil body 11 to electrically connect the secondary coil 3 to the spark plug via a high-voltage terminal 45 and a spring 46. The coil body 11 is mounted on the cylinder head cover 7, while the connector 12 is disposed in a plug hole 71 formed in the cylinder head cover 7.

[0046] (Axial direction L, mounting direction D, and width direction W)

[0047] exist Figure 1-7 In this diagram, axis L represents the direction in which the central axes of the primary coil 2 and the secondary coil 3 extend. Furthermore, along axis L, the side of the secondary coil 3 that generates high voltage is called the high-voltage side L1; the side opposite to the high-voltage side L1 is called the low-voltage side L2.

[0048] Installation direction D indicates that connector 24 is installed into coil housing 5 (see...). Figure 7 ) and ignition coil 1 are installed on the internal combustion engine cylinder head cover 7 (see Figure 1 The direction of the mounting direction (D) is more specifically, the mounting direction D is perpendicular to the axial direction L, and the opening 52 and the bottom 53 of the coil housing 5 are aligned with each other in this direction. Furthermore, in the mounting direction D, the side where the bottom 53 and the spark plug are located is called the bottom side D1; the side opposite to the bottom side D1 and where the opening 52 is located is called the opening side D2.

[0049] The width direction W represents the direction perpendicular to the axial direction L and the mounting direction D.

[0050] (Primary coil 2)

[0051] like Figure 1-3 As shown, a primary coil 2 is formed by winding magnetic wire (or a winding) around the outer peripheral surface of the tubular portion 22 of the primary spool 21. The power supply to the primary coil 2 is selectively enabled and interrupted by the switching element of the igniter 43.

[0052] (Secondary coil 3)

[0053] like Figure 1-3As shown, the secondary coil 3 is disposed outside the primary coil 2 and coaxial with the primary coil 2. The secondary coil 3 is formed by winding magnetic wire (or a winding) around the outer peripheral surface of the tubular portion 32 of the secondary coil spool 31. The winding constituting the secondary coil 3 is thinner than the winding constituting the primary coil 2; the number of turns of the secondary coil 3 is greater than the number of turns of the primary coil 2. The secondary coil 3 is configured to generate an induced electromotive force through the induced interaction between the primary coil 2 and the secondary coil 3 when the power supply to the primary coil 2 is interrupted. The central axes of the primary coil 2 and the secondary coil 3 are oriented perpendicular to the opening 52 of the coil housing 5. One end of the secondary coil 3 (i.e., the end located on the low-pressure side L2 in the axial direction L) is connected to the ground or power terminal of the igniter 43. The other end of the secondary coil 3 (i.e., the end located on the high-pressure side L1 in the axial direction L) is connected to the high-voltage terminal 45, which is connected to the center electrode of the spark plug.

[0054] (Center Core 41)

[0055] like Figure 1-3 As shown, the central core 41 is arranged within the primary coil 2 to allow the magnetic flux generated by the primary coil 2 and the secondary coil 3 to flow through it. In this embodiment, the central core 41 is formed by laminating multiple magnetic steel plates made of soft magnetic material. Furthermore, the central core 41 is formed into a cuboid. Alternatively, the central core 41 can be formed by compacting soft magnetic material powder.

[0056] (outer core 42)

[0057] like Figure 1-3 As shown, the outer core 42 is arranged outside the secondary coil 3 to allow the magnetic flux generated by the primary coil 2 and the secondary coil 3 to flow through it. In this embodiment, the outer core 42 is formed by laminating multiple magnetic steel plates made of soft magnetic material. Furthermore, the outer core 42 is a four-sided ring, so when viewed along the mounting direction D, the outer core 42 surrounds the primary coil 2, the secondary coil 3, and the central core 41. Alternatively, the outer core 42 can be formed by compacting soft magnetic material powder.

[0058] The outer core 42 has a pair of side cores 421, which are located on opposite sides of the secondary coil 3 in the width direction W (see...). Figure 3 ), and a pair of connecting cores 422, which are respectively located on the high-voltage side L1 and the low-voltage side L2 of the secondary coil 3 along the axial direction L (see Figure 2 ), and each connecting core connects to the opposite core 421.

[0059] The igniter 43 is arranged to face the connecting core 422 of the outer core 42, which is located on the low-voltage side L2 of the secondary coil 3 in the axial direction L. There is almost no gap between the igniter 43 and the connecting core 422 facing the igniter 43, so there is almost no electrical insulating fixing resin 6.

[0060] The central core 41 and the outer core 42 together form a closed magnetic circuit through which magnetic flux flows. Between the central core 41 and the outer core 42, a permanent magnet 44 is arranged to prevent magnetic saturation.

[0061] (Igniter 43)

[0062] like Figure 1 and 4 As shown, the igniter 43 is arranged between the connector 24 mounted to the coil housing 5 and the connecting core 422 of the outer core 42 facing the igniter 43 along the axial direction L.

[0063] The igniter 43 includes a circuit forming portion 431, a heat sink 432, molding resin 433, and an igniter conductor 434 (i.e., an electrical conductor of the igniter 43). The circuit forming portion 431 includes electronic components for forming a switching circuit, such as the aforementioned switching element. The heat sink 432 is integrated with the circuit forming portion 431. The molding resin 433 has the circuit forming portion 431 and the heat sink 432 embedded therein. The igniter conductor 434 extends from the circuit forming portion 431 to the outside of the molding resin 433.

[0064] More specifically, the igniter conductor 434 extends from the molding resin 433 to the opening side D2 in the mounting direction D. The switching element of the igniter 43 is configured to receive commands from an external electronic control device (not shown) arranged outside the ignition coil 1, and selectively enable and interrupt the power supply to the primary coil 2 according to the received commands. During operation of the ignition coil 1, heat is mainly generated in the igniter 43 by the switching element. The heat generated in the igniter 43 is then dissipated via the heat sink 432 to the connecting core 422 of the outer core 42 facing the igniter 43.

[0065] (Elementary spool 21)

[0066] like Figure 1 , 2 As shown in Figure 4, a primary coil 2 is wound around the outer periphery of the primary spool 21. The primary spool 21 is made of thermoplastic resin molding. The primary spool 21 has an abutment portion 231 that abuts against the end of the igniter 43 on the open side D2 in the mounting direction D. The abutment portion 231 extends from the end of the primary spool 21 on the low-pressure side L2 in the axial direction L, across the end of the outer core 42 connecting the core 422 on the open side D2 in the mounting direction D, to the end of the igniter 43 on the open side D2 in the mounting direction D. The igniter 43 is clamped (i.e., fixedly held) between the abutment portion 231 of the primary spool 21 and the housing side rib 54, thereby being located in the coil housing 5 in the mounting direction D.

[0067] like Figure 2As shown, in this embodiment, the primary spool 21 and the connector portion 240 constituting the connector 24 are integrally molded into a spool forming molded body 210. More specifically, the spool forming molded body 210 has a quadrilateral tubular portion 22, a pair of collar portions 221 (which are respectively formed at opposite ends of the tubular portion 22 in the axial direction L), the connector portion 240 constituting the connector 24, and an interconnecting portion 23 interconnecting the tubular portion 22 and the connector portion 240. That is, in this embodiment, the connector 24 and the primary spool 21 are integrally formed as a whole. Furthermore, the abutment portion 231 is included in the interconnecting portion 23.

[0068] like Figure 4 As shown, a recess 232 is formed on the bottom side D1 of the interconnection portion 23 along the mounting direction D, in which the connecting core 422 of the outer core 42 and the igniter 43 are received. Furthermore, an insertion hole 233 adjacent to the abutment portion 231 is formed in the interconnection portion 23; the igniter conductor 434 and the connector conductor 25 (i.e., the electrical conductor of the connector 24) are inserted through the insertion hole 233. Additionally, the connector portion 240 constituting the connector 24 can alternatively be formed separately from the tubular portion 22 of the primary spool 21.

[0069] The winding constituting the primary coil 2 is wound between a pair of loop portions 221 on the outer peripheral surface of the tubular portion 22 of the primary spool 21. In the connector portion 240 constituting the connector 24, there are embedded molded connector conductors 25, which are respectively connected to the igniter conductors 434. The connector portion 240 is formed to extend beyond the coil housing 5. In the connector portion 240 (i.e., connector 24), a connector wall portion 241 is formed, which constitutes a portion of the axial low-pressure side L2 of the coil housing 5 wall.

[0070] In the coil housing 5, the igniter conductor 434 and the connector conductor 25 are arranged on the open side D2 in the mounting direction D, such that the igniter conductor 434 faces the connector conductor 25 respectively. Furthermore, the igniter conductor 434 is connected to the connector conductor 25 by means of, for example, brazing or welding. Additionally, the igniter conductor 434 can also be connected by, for example, brazing or welding to coil conductors connected to the opposite ends of the winding constituting the primary coil 2 and coil conductors connected to the low-voltage side ends of the winding constituting the secondary coil 3.

[0071] (Secondary spool 31)

[0072] like Figure 2 and 3As shown, a secondary coil 3 is wound around the outer periphery of a secondary spool 31. The secondary spool 31 is made of thermoplastic resin molding. The secondary spool 31 has a tubular portion 32 formed as a quadrilateral tube, and a plurality of collar portions 33 formed at multiple locations along the axial direction L to protrude from the outer periphery of the tubular portion 32. The collar portions 33 divide the outer periphery of the tubular portion 32 into a plurality of recesses 321, which are aligned with each other along the axial direction L. The winding constituting the secondary coil 3 is wound around the outer periphery of the tubular portion 32, thereby being distributed among the recesses 321.

[0073] (Coil housing 5)

[0074] like Figure 1 and 7 As shown, the coil housing 5 is made of thermoplastic resin molding. The coil housing 5 has a receiving part 51, which receives the primary coil 2, secondary coil 3, center core 41, outer core 42, igniter 43, etc. An opening 52 is formed at the end of the receiving part 51 on the opening side D2 in the mounting direction D.

[0075] During the manufacturing process of the ignition coil 1, the coil assembly 10, obtained by assembling the primary coil 2, primary bobbin 21, secondary coil 3, secondary bobbin 31, center core 41, outer core 42, and igniter 43 together, is inserted into the receiving part 51 of the coil housing 5 through the opening 52. Then, liquid electrically insulating fixing resin 6 is filled into the space in the coil housing 5 through the opening 52.

[0076] On a portion of the coil housing 5, a connector portion 240 is arranged for electrically connecting the igniter 43 to an external electronic control device via a spool molding body 210. The spool molding body 210 is obtained by resin embedding molding, such that the central core 41 is located in the tubular portion 22 of the primary spool 21, and the connector conductor 25 is located in the connector portion 240.

[0077] like Figure 4 As shown, a cutout (or recess) 56 is formed in the coil housing 5, and the connector portion 240 of the spool forming molded body 210 is mounted to this cutout (or recess) 56. Therefore, a portion of the axial low-voltage side L2 of the coil housing 5 wall is formed by the connector wall portion 241. Retaining portions 242 are formed at the ends of the connector wall portion 241 on the bottom side D1 in the mounting direction D and on both sides in the width direction W, respectively. Each retaining portion 242 retains (or clamps) an edge portion of the cutout 56 of the coil housing 5 from both sides.

[0078] In addition, such as Figure 1As shown, a tower portion 57 constituting the connector portion 12 is formed on the bottom 53 of the coil housing 5 located on the bottom side D1 in the mounting direction D. Furthermore, a sealing rubber 58 for sealing between the ignition coil 1 and the plug hole 71 is installed on the tower portion 57.

[0079] (Shell side rib 54)

[0080] like Figure 4-6 As shown, a housing side rib 54 is formed on the inner surface of the coil housing 5, which defines the inner corner 531 of the coil housing 5 on the bottom side D1 in the mounting direction D and the low-voltage side L2 in the axial direction L. Furthermore, when viewed along the width direction W, the housing side rib 54 is triangular and has a sloping side (or distal end) 541 extending obliquely in both the axial direction L and the mounting direction D. Moreover, as the housing side rib 54 extends from the inner surface of the coil housing 5 along the axial direction L to the high-voltage side L1, the width of the housing side rib 54 decreases in the width direction W. Furthermore, the housing side rib 54 gradually tapers from its root position (i.e., from the inner corner 531 of the coil housing 5) to the sloping side 541. In other words, in any cross-section of the housing side rib 54 perpendicular to the line representing the distal edge of the sloping side 541, the width of the housing side rib 54 in the width direction W decreases from the inner surface of the coil housing 5 to the sloping side 541.

[0081] like Figure 4 As shown, in this embodiment, the housing side rib 54 is formed so thin that it can undergo plastic deformation when the igniter 43 comes into contact with it. More specifically, the housing side rib 54 is formed such that its width in the width direction W is less than the minimum thickness of the coil housing 5. In the coil housing 5, the housing side rib 54 is formed in a position such that when the igniter 43 is inserted into the coil housing 5 through the opening 52, a portion of the inclined side 541 of the housing side rib 54 will be crushed (or plastically deformed) by the corner of the igniter 43 on the bottom side D1 in the mounting direction D and the low-pressure side L2 in the axial direction L.

[0082] With the above configuration, the igniter 43 can be pressed against the connecting core 422 of the outer core 42 by the housing side rib 54, and the igniter 43 can be reliably kept under pressure.

[0083] In this embodiment, only one housing side rib 54 is formed on the inner corner 531 of the coil housing 5 on the bottom side D1 in the mounting direction D and the low-voltage side L2 in the axial direction L, at a position corresponding to the center position of the igniter 43 in the width direction W. As an alternative, such as Figure 8 As shown, multiple housing side ribs 54 aligned with each other in the width direction W can be formed on the inner corner 531 of the coil housing 5.

[0084] In addition, one or more housing side ribs 54 can be replaced by having a sufficiently large width in the width direction W, thereby having sufficiently high rigidity so that they are hardly plastically deformed by the igniter 43.

[0085] (Electrically insulating fixing resin 6)

[0086] The electrically insulating fixing resin 6 is formed from a thermosetting resin. Specifically, such as... Figure 1 and 7 As shown, during the manufacturing process of the ignition coil 1, the coil assembly 10, obtained by assembling the primary coil 2, primary spool 21, secondary coil 3, secondary spool 31, center core 41, outer core 42, and igniter 43 together, is placed in the coil housing 5. Then, liquid thermosetting resin is filled into the space within the coil housing 5 and cured therein to form an electrically insulating fixing resin 6. Therefore, using the electrically insulating fixing resin 6, all the primary coil 2, primary spool 21, secondary coil 3, secondary spool 31, center core 41, outer core 42, and igniter 43 are fixed to each other within the coil housing 5; and the primary coil 2, secondary coil 3, center core 41, outer core 42, and igniter 43 are electrically insulated from each other.

[0087] (The gap between igniter 43 and outer core 42)

[0088] Preferably, the igniter 43 and the connecting core 422 of the outer core 42 facing the igniter 43 are in close contact with each other. Alternatively, a gap of less than or equal to 0.13 mm may be formed between the igniter 43 and the connecting core 422 of the outer core 42 facing the igniter 43. Here, 0.13 mm is specified as the value required to keep the temperature of the igniter 43 below or equal to 150°C, even when the amount of electrical power consumed by the igniter 43 increases with the increase of the output of the ignition coil 1.

[0089] (The contact between the igniter 43 and the side rib of the housing 54)

[0090] Igniter 43 is arranged relative to coil assembly 10, wherein primary coil 2, secondary coil 3, secondary bobbin 31, center core 41, and outer core 42 are assembled into bobbin forming molded body 210. Furthermore, as... Figure 7 As shown, when the connector wall portion 241 of the connector portion 240 of the spool forming molded body 210 included in the coil assembly 10 is installed into the cutout 56 of the coil housing 5, the igniter 43 is placed in the coil housing 5.

[0091] like Figure 4As shown, the igniter 43 abuts against the abutting portion 231 provided in the interconnecting portion 23 of the linear shaft forming molded body 210, thereby restricting its movement to the opening side D2 in the mounting direction D. Furthermore, the igniter conductor 434 extending from the end of the igniter 43 on the opening side D2 in the mounting direction D abuts against the connector conductor 25 of the connector portion 240, thereby restricting the igniter 43 from moving to the low-pressure side L2 in the axial direction L.

[0092] like Figure 4 As shown, when the connector wall portion 241 is installed into the cutout 56 of the coil housing 5, the corner of the igniter 43 on the bottom side D1 in the mounting direction D and the low-voltage side L2 in the axial direction L abuts against the oblique side portion 541 of the housing side rib 54. Furthermore, at this time, the igniter 43 is pressed by the oblique side portion 541 of the housing side rib 54 towards the connecting core portion 422 of the outer core 42 facing the igniter 43, thereby abutting against the connecting core portion 422 of the outer core 42.

[0093] Therefore, when the connector wall portion 241 moves further to the final installation position on the bottom side D1 of the mounting direction D, a portion of the oblique side portion 541 of the housing side rib 54 is crushed by the corner of the igniter 43 on the bottom side D1 of the mounting direction D and the low-pressure side L2 of the axial direction L. The igniter 43 is supported by the abutment portion 231 provided in the interconnection portion 23 of the linear shaft forming molding body 210. Thus, the igniter 43 bites into a portion of the oblique side portion 541 of the housing side rib 54, forming an indentation 542 therein.

[0094] (Operational effect)

[0095] In the ignition coil 1 according to this embodiment, a housing side rib 54 is formed on the inner surface of the coil housing 5; the igniter 43 is pressed against the connecting core 422 of the outer core 42 facing the igniter 43 by the housing side rib 54. More specifically, the housing side rib 54 is configured to press the end of the igniter 43 at the bottom side D1 of the mounting direction D against the connecting core 422 of the outer core 42 to prevent the end of the igniter 43 from separating from the connecting core 422 of the outer core 42.

[0096] Furthermore, the housing side rib 54 has a tapered shape, such that the amount of protrusion of the housing side rib 54 toward the high-voltage side L1 in the axial direction D increases toward the bottom side D1 along the mounting direction D. When the igniter 43, which has been assembled into the spool forming molded body 210, is placed into the coil housing 5, the corners of the igniter 43 on the bottom side D1 in the mounting direction D and the low-voltage side L2 in the axial direction L abut against the oblique side 541 of the housing side rib 54.

[0097] At this time, the igniter 43 slides on the inclined side 541 of the housing side rib 54, thereby shifting towards the connecting core 422 of the outer core 42. Therefore, the igniter 43 can be appropriately pressed against the outer core 42. Furthermore, the igniter 43, pressed against the connecting core 422 of the outer core 42, is sandwiched between the abutment portion 231 of the primary spool 21 and the housing side rib 54 in the coil housing 5. Therefore, heat can be dissipated from the igniter 43 to the outer core 42 more effectively.

[0098] On the other hand, in conventional ignition coils, the housing side ribs 54 are not formed in the coil housing 5. The igniter 43 can be tilted relative to the mounting direction D in the coil housing 5 where the coil assembly 10 is provided, causing the end of the igniter 43 located on the bottom side D1 of the mounting direction D to separate from the connecting core 422 of the outer core 42. In this case, the heat dissipation (or heat transfer) efficiency from the igniter 43 to the connecting core 422 of the outer core 42 will be reduced. Conversely, in the ignition coil 1 according to this embodiment, the reduction in heat dissipation efficiency from the igniter 43 to the connecting core 422 of the outer core 42 can be prevented.

[0099] In summary, by configuring the ignition coil 1 according to this embodiment, the heat dissipation efficiency from the igniter 43 to the outer core 42 can be improved.

[0100] [Second Embodiment]

[0101] The ignition coil 1 according to the second embodiment has a similar configuration to the ignition coil 1 according to the first embodiment. Therefore, the differences between them will be mainly described below.

[0102] As previously described, in the ignition coil 1 according to the first embodiment, a housing side rib 54 is formed in the coil housing 5.

[0103] Conversely, in the ignition coil 1 according to this embodiment, such as Figure 9 and 10 As shown, no housing side ribs 54 are formed in the coil housing 5. Instead, connector side ribs 26 are formed in the connector portion 240 of the spool molding body 210 that constitutes the connector 24. Furthermore, Figure 10 Connector 24 is shown as viewed from the high-pressure side L1 along the axial direction.

[0104] In this embodiment, as Figure 11 As shown, when the igniter 43 is assembled onto the spool forming mold 210 to form the coil assembly 10, the igniter 43 is pressed against the outer core 42 connecting core 422 facing the igniter 43 by the connector side rib 26.

[0105] More specifically, in this embodiment, such as Figure 9 and 11As shown, similar to the first embodiment, the primary spool 21 and the connector portion 240 constituting the connector 24 are integrally molded as a spool forming molded body 210. On the inner surface of the connector wall portion 241 of the connector portion 240, a connector side rib 26 is formed for pressing the igniter 43 against the outer core 42. The connector side rib 26 has a tapered portion 261 and a straight portion 262. The tapered portion 261 is tapered such that the amount of the tapered portion 261 protruding from the inner surface of the connector wall portion 241 toward the axial high-pressure side L1 increases along the mounting direction D toward the opening side D2. The straight portion 262 is formed on the opening side D2 of the tapered portion 261 and is continuous with the tapered portion 261. The straight portion 262 is shaped to be straight such that the amount of the straight portion 262 protruding from the inner surface of the connector wall portion 241 toward the axial high-pressure side L1 is constant in the mounting direction D.

[0106] Furthermore, in this embodiment, the tapering portion 261 of the connector side rib 26 is formed such that its width in the width direction W decreases towards the bottom side D1 along the mounting direction D. For example... Figure 10 As shown, only one connector side rib 26 is formed on the inner surface of the connector wall 241 at a position corresponding to the center position of the igniter 43 in the width direction W. Alternatively, although not shown in the figures, multiple connector side ribs 26 aligned with each other in the width direction W can be formed on the inner surface of the connector wall 241. Furthermore, one or more connector side ribs 26 can be formed without a straight portion 262, i.e., only a tapered portion 261.

[0107] (The contact between the igniter 43 and the connector side rib 26)

[0108] In this embodiment, as Figure 11 As shown, the igniter 43 is assembled into the bobbin forming mold 210 to form the coil assembly 10; the bobbin forming mold 210 has a primary coil 2, a secondary coil 3, a secondary bobbin 31, a center core 41, and an outer core 42 already assembled thereon. More specifically, the igniter 43 is assembled into the bobbin forming mold 210 by inserting it into a recess 232 formed in the bobbin forming mold 210. During the insertion of the igniter 43 into the recess 232, the corners of the igniter 43 on the opening side D2 in the mounting direction D and the low-pressure side L2 in the axial direction abut against the tapered portion 261 of the connector side rib 26.

[0109] Furthermore, at this time, the igniter 43 is pressed against the connecting core 422 of the outer core 42 by the tapered portion 261 of the connector side rib 26, thereby abutting against the connecting core 422 of the outer core 42. Then, as the igniter 43 moves further to the opening side D2 in the mounting direction D, the side of the igniter 43 abuts against the straight portion 262 of the connector side rib 26, thereby keeping the igniter 43 pressed against the connecting core 422 of the outer core 42.

[0110] Furthermore, the igniter 43 abuts against the abutting portion 231 provided in the interconnecting portion 23 of the spool molding body 210, thereby restricting its movement to the opening side D2 in the mounting direction D. Thereafter, when the connector wall portion 241 of the connector portion 240 of the spool molding body 210 is installed into the cutout 56 of the coil housing 5, the coil assembly 10 having the igniter 43 assembled to the spool molding body 210 is placed into the receiving portion 51 of the coil housing 5 (see...). Figure 9 ).

[0111] (Operational effect)

[0112] In the ignition coil 1 according to this embodiment, a connector side rib 26 is formed on the inner surface of the connector wall portion 241 of the connector portion 240 constituting the connector 24; the connector wall portion 241 is mounted to the coil housing 5. The connector side rib 26 presses the igniter 43 against the outer core 42 connecting core 422 facing the igniter 43. The connector side rib 26 has a taper 261, which tapers such that the amount of protrusion of the taper 261 from the inner surface of the connector wall portion 241 toward the axial high-voltage side L1 increases along the mounting direction D toward the opening side D2. When the igniter 43 is assembled to the spool forming molded body 210 to form the coil assembly 10, the igniter 43 abuts against the taper 261 of the connector side rib 26.

[0113] At this time, the igniter 43 slides on the tapered portion 261 of the connector side rib 26, thereby shifting towards the connecting core 422 of the outer core 42. Therefore, the igniter 43 can be appropriately pressed against the outer core 42. Furthermore, the igniter 43, pressed against the connecting core 422 of the outer core 42, is sandwiched between the abutment portion 231 of the primary spool 21 and the connector side rib 26 in the coil housing 5. Therefore, heat can be dissipated from the igniter 43 to the outer core 42 more effectively.

[0114] In summary, by configuring the ignition coil 1 according to this embodiment, the heat dissipation efficiency from the igniter 43 to the outer core 42 can be improved.

[0115] In addition, such as Figure 12 As shown, the ignition coil 1 according to this embodiment can be modified to further have a housing side rib 54 formed in the coil housing 5. In this case, the igniter 43 is pressed against the connecting core 422 of the outer core 42 facing the igniter 43 by the connector side rib 26 and the housing side rib 54. Therefore, the igniter 43 and the connecting core 422 of the outer core 42 can be brought into close contact with each other more effectively.

[0116] [Third Embodiment]

[0117] The ignition coil 1 according to the third embodiment has a similar configuration to the ignition coil 1 according to the first and second embodiments. Therefore, the differences between them will be mainly described below.

[0118] As previously mentioned, in the ignition coil 1 according to the first and second embodiments, the connector 24 and the primary spool 21 are integrally formed as a whole.

[0119] Conversely, in the ignition coil 1 according to this embodiment, such as Figure 13 As shown, connector 24 is formed separately from primary spool 21.

[0120] Furthermore, in this embodiment, such as Figure 14 As shown, when the connector wall 241 of the connector 24 is installed into the cutout 56 of the coil housing 5 where the igniter 43, outer core 42, etc. are placed, the igniter 43 is pressed by the connector 24 against the connecting core 422 of the outer core 42 facing the igniter 43.

[0121] More specifically, in this embodiment, such as Figure 13 As shown, a connector side rib 26, as in the second embodiment, is formed on the inner surface of the connector wall portion 241 of the connector 24. The connector wall portion 241 is mounted to the cutout 56 of the coil housing 5 to form part of the coil housing 5. Furthermore, in this embodiment, an abutment portion 27 is also formed on the inner surface of the connector wall portion 241, which abuts against the end of the igniter 43 at the opening side D2 in the mounting direction D.

[0122] The abutment portion 27 is continuously formed with the connector side rib 26. More specifically, the abutment portion 27 is formed on the opening side D2 of the connector side rib 26 in the mounting direction D, adjacent to the connector side rib 26. The abutment portion 27 restricts the movement of the igniter 43 towards the opening side D2 in the mounting direction D. It should be noted that the abutment portion 27 can alternatively be formed separately from the connector side rib 26. Furthermore, a plurality of abutment portions 27 aligned with each other in the width direction W can be formed.

[0123] In this embodiment, as Figure 13 As shown, a housing side rib 54, as in the first embodiment, is formed on the inner surface of the inner corner 531 of the coil housing 5, which defines the mounting direction D bottom side D1 and the axial direction L low-pressure side L2. The shape of the housing side rib 54 prevents it from being plastically deformed by the igniter 43. Furthermore, in this embodiment, an abutment portion 55, continuous with the housing side rib 54, is formed on the inner surface of the bottom 53 of the coil housing 5, thereby abutting against the end of the igniter 43 at the mounting direction D bottom side D1. It should be noted that the abutment portion 55 may alternatively be formed separately from the housing side rib 54. In addition, multiple abutment portions 55 aligned with each other in the width direction W may be formed.

[0124] The igniter 43 can be supported from the bottom side D1 in the mounting direction D by means of the abutment portion 55 formed in the coil housing 5. The igniter 43 is sandwiched between the abutment portion 27 of the connector 24 and the abutment portion 55 of the coil housing 5, and is therefore located in the coil housing 5 in the mounting direction D.

[0125] It should be noted that the contact portion 55 may also be formed in the coil housing 5 of the ignition coil 1 according to the first embodiment, wherein the primary spool 21 and the connector 24 are integrally molded as a spool forming molded body 210.

[0126] (The contact between the igniter 43 and the connector side rib 26)

[0127] In this embodiment, the igniter 43 is placed together with the coil assembly 10 in the coil housing 5, wherein the primary coil 2, secondary coil 3, secondary bobbin 31, center core 41, and outer core 42 are assembled into the bobbin forming molded body 210. Then, as... Figure 14 As shown, the connector wall 241 of the connector 24 is mounted to the cutout 56 of the coil housing 5.

[0128] At this time, the corner of the igniter 43 on the opening side D2 in the mounting direction D and the low-pressure side L2 in the axial direction L abuts against the tapered portion 261 of the connector side rib 26. Furthermore, the igniter 43 is pressed by the tapered portion 261 of the connector side rib 26 towards the connecting core 422 of the outer core 42 facing the igniter 43, thereby abutting against the connecting core 422 of the outer core 42. Then, as the connector wall portion 241 of the connector 24 moves further towards the bottom side D1 in the mounting direction D, the abutting portion 27 of the connector 24 and the abutting portion 55 of the coil housing 5 both abut against the igniter 43. Therefore, the igniter 43 is located in the coil housing 5 along the mounting direction D and remains in a state where it is pressed against the connecting core 422 of the outer core 42 facing the igniter 43.

[0129] The ignition coil 1 according to this embodiment has the same operating effect as the ignition coil 1 according to the first and second embodiments.

[0130] [Fourth Embodiment]

[0131] Figure 15-24 An ignition coil 1 according to a fourth embodiment is shown. In these ignition coils 1, for each pair of connected igniter conductors 434 (i.e., the electrical conductor of igniter 43) and connector conductors 25 (i.e., the electrical conductor of connector 24), at least one of each pair of connected igniter conductors 434 and connector conductors 25 has an elastically deformable portion 435 or 253 formed.

[0132] Specifically, each igniter conductor 434 protrudes from the end of the igniter 43 molding resin 433 at the opening side D2 in the mounting direction D towards the opening side D2. On the other hand, one end of each connector conductor 25 protrudes from the connector portion 240 of the spool molding body 210 towards the outside of the coil housing 5, and the other end protrudes from the connector portion 240 towards the inside of the coil housing 5 (see...). Figure 1 and 2 ).

[0133] Furthermore, each connector conductor 25 faces and connects to a corresponding igniter conductor 434 along the axial direction L. For each pair of corresponding connector conductors 25 and igniter conductors 434, at least one of the corresponding pair of connector conductors 25 and igniter conductors 434 is formed to be slightly inclined toward the direction in which they approach each other, so as to facilitate close contact between them.

[0134] Figure 15 A portion of the ignition coil 1 according to this embodiment is shown. In this ignition coil 1, an elastically deformable portion 253 is formed in each connector conductor 25. The elastically deformable portion 253 is composed of a folded-back portion 254 that is substantially U-shaped and has an elastically deformable spring structure. More specifically, each connector conductor 25 is formed of a conductive plate-like material. A portion of the plate-like material is folded back along the thickness direction perpendicular to the plate surface to form the folded-back portion 254. Each connector conductor 25 is bent to have a facing portion 251 facing the corresponding igniter conductor 434 and a non-facing portion 252 extending perpendicular to the facing portion 251 and not facing the corresponding igniter conductor 434. The folded-back portion 254 is formed in the non-facing portion 252. Furthermore, in the facing portion 251, a protrusion 251A that contacts the igniter conductor 434 is formed.

[0135] Turnback section 254 can be as follows Figure 15 The bend shown, or as Figure 16 The fold-back shown is to have a pair of parallel portions. As an alternative, the fold-back portion 254 can be folded back multiple times to have more than two parallel portions, such as... Figure 17 As shown.

[0136] like Figure 18 As shown, the foldback portion 254 can alternatively be formed by folding back the distal end of the face portion 251. Furthermore, in this case, the foldback portion 254 can be formed having two or more portions parallel to the corresponding ignition conductor 434.

[0137] Figure 19A portion of another ignition coil 1 according to this embodiment is shown. In this ignition coil 1, an elastically deformable portion 435 is formed in each igniter conductor 434. The elastically deformable portion 435 is composed of a bent portion 436 that is substantially Z-shaped and has an elastically deformable spring structure. More specifically, each igniter conductor 434 is formed of a conductive plate-like material. A portion of the plate-like material is folded back along the thickness direction perpendicular to the plate surface to form the bent portion 436. Furthermore, the bent portion 436 is offset towards the low-pressure side L2 of the axial direction L from the end of the igniter conductor 434 that extends from the opening side D2 of the mounting direction D of the igniter 43.

[0138] Can be modified Figure 19 The ignition coil 1 shown is such that each connector conductor 25 has a... Figure 15-18 The elastic deformation portion 253 (or folding portion 254) shown is provided, and each igniter conductor 434 has an elastic deformation portion 435 (or bending portion 436) formed therein.

[0139] like Figure 20 As shown, the elastic deformation portion 253 can alternatively be constituted by a narrowing portion 255, where the thickness and therefore cross-sectional area of ​​the connector conductor 25 are reduced. The narrowing portion 255 can constitute the starting point of the elastic deformation of the connector conductor 25, since the thickness and therefore cross-sectional area of ​​the connector conductor 25 are minimum at the narrowing portion 255. Furthermore, in this case, the narrowing portion 255 can be formed in the non-facing portion 252 of the connector conductor 25, which extends perpendicular to the facing portion 251 and does not face the corresponding ignition conductor 434. In addition, the narrowing portion 255 can be obtained by reducing the thickness of a portion of the plate-like material forming the connector conductor 25.

[0140] like Figure 21 As shown, the elastic deformation portion 435 can instead be constituted by a narrowing portion 437, where the thickness and therefore the cross-sectional area of ​​the ignition conductor 434 are reduced. Furthermore, as... Figure 22 As shown, the elastic deformation portion 253 may be composed of the narrowing portion 255, while the elastic deformation portion 435 may be composed of the narrowing portion 437.

[0141] like Figure 23 As shown, the narrowed portion 255 can alternatively be obtained by reducing the width of a portion of the plate-like material forming the non-facing portion 252 of the connector conductor 25. Furthermore, Figure 23 A portion of the ignition coil 1 is shown as viewed from the opening side D2 in the mounting direction D.

[0142] like Figure 24 As shown, the narrowing 437 can alternatively be obtained by reducing the width of a portion of the plate-like material forming the ignition conductor 434. Furthermore, Figure 24A portion of the ignition coil 1 is shown as viewed from the high-voltage side L1 along the axial direction L.

[0143] (Operational effect)

[0144] When the igniter 43 is pressed against the connecting core 422 of the outer core 42 facing the igniter 43 by the housing side rib 54 or the connector side rib 26, stress will be induced in the contact portion of each corresponding pair of connector conductors 25 and igniter conductors 434. At this time, for each corresponding pair of connector conductors 25 and igniter conductors 434, the elastic deformation portion 253 of the connector conductor 25 and / or the elastic deformation portion 435 of the igniter conductor 434 will undergo elastic deformation, thereby reducing the stress induced in the contact portion of the connector conductors 25 and igniter conductors 434. Therefore, during the assembly of the ignition coil 1, unnecessary stress can be prevented from being induced in the circuit forming portion 431 of the igniter 43; the circuit forming portion 431 includes switching elements.

[0145] It should be noted that the aforementioned elastic deformation portions 253 and 435 can also be formed in the connector conductor 25 and igniter conductor 434 of the ignition coil 1 according to the third embodiment, wherein the connector 24 is formed separately from the primary spool 21. Furthermore, each connector conductor 25 may have both a folded-back portion 254 and a narrowed portion 255 as its elastic deformation portion 253. Similarly, each igniter conductor 434 may have both a bent portion 436 and a narrowed portion 437 as its elastic deformation portion 435.

[0146] While specific embodiments and modifications have been shown and described above, those skilled in the art will understand that various further modifications, alterations and improvements can be made without departing from the spirit of this disclosure.

Claims

1. An ignition coil (1) for an internal combustion engine, the ignition coil comprising: Primary coil (2), which is configured to be powered; A secondary coil (3) is disposed outside the primary coil and coaxial with the primary coil, the secondary coil being configured to generate an induced electromotive force when the power supply to the primary coil is interrupted. The center core (41) is disposed inside the primary coil; The outer core (42) is a four-sided ring, with its four parts located on opposite sides of the secondary coil in the axial direction (L) and opposite sides of the secondary coil in the width direction (W) perpendicular to the axial direction. The outer core and the central core together form a closed magnetic circuit in the ignition coil. An igniter (43) includes a switching element configured to selectively enable and interrupt power supply to the primary coil, the igniter being disposed adjacent to the outer core on the axial low-voltage side (L2) of the outer core; The coil housing (5) has an opening (52) on one side of the mounting direction (D) and a bottom (53) on the other side of the mounting direction, the mounting direction being perpendicular to both the axial direction and the width direction, and the coil housing receives all of the primary coil, the secondary coil, the center core, the outer core and the igniter; as well as Electrically insulating fixing resin (6) fills the space in the coil housing to fix the primary coil, the secondary coil, the center core, the outer core, and the igniter in the coil housing while electrically insulating them from each other. in On the inner surface of the bottom side of the coil housing in the mounting direction, a housing side rib is formed that protrudes from the inner surface of the coil housing to the high-voltage side (L1) in the axial direction, the high-voltage side being opposite to the low-voltage side in the axial direction. The housing side ribs have a tapering shape, such that the amount of protrusion of the housing side ribs towards the axial high-pressure side increases along the mounting direction toward the bottom side, and The housing side ribs are configured to abut against the corners of the igniter at the bottom side in the installation direction and the corners of the axial low-pressure side, thereby pressing the igniter against the outer core.

2. The ignition coil of claim 1, wherein the housing side rib has an oblique side (541) extending obliquely relative to the axial direction and the mounting direction. The housing side ribs are tapered, such that their width in the width direction decreases from the inner surface of the coil housing to the inclined side portion. The housing side ribs are formed in such a position that, during the insertion of the igniter into the coil housing from the opening, a portion of the sloping side is crushed by the corner of the igniter.

3. The ignition coil as described in claim 1 further includes a primary spool (21) on which the primary coil is wound. in The primary spool has an abutment portion (231) that abuts against the end of the igniter on the open side in the mounting direction, and On the inner surface of the bottom of the coil housing, an abutment portion (55) is formed that is continuous with or separate from the side ribs of the housing, so as to abut the end of the igniter on the bottom side in the mounting direction.

4. The ignition coil of claim 1, further comprising a connector (24) mounted to the coil housing to protrude outside the coil housing, the connector having a connector wall portion (241) forming part of the coil housing on the axial low-pressure side. in On the inner surface of the connector wall, a connector side rib (26) is formed that protrudes from the inner surface of the connector wall to the axial high-pressure side (L1). The connector side rib has a taper (261) such that the amount of the taper protruding from the inner surface of the connector wall to the axial high-pressure side increases along the mounting direction toward the opening side, and The connector side ribs are configured to press the igniter against the outer core.

5. The ignition coil as claimed in claim 4, wherein an abutment portion (27) is further formed on the inner surface of the connector wall, which abuts against the end of the igniter on the opening side in the mounting direction.

6. The ignition coil of claim 4, wherein the igniter includes an electrical conductor (434) protruding from an end of the igniter on the opening side in the mounting direction to the opening side. The connector includes an electrical conductor (25) configured to face and connect to the electrical conductor of the igniter in the axial direction, and... At least one of the electrical conductors of the igniter and the connector has an elastically deformable portion (435, 253) formed in it.

7. An ignition coil (1) for an internal combustion engine, the ignition coil comprising: Primary coil (2), which is configured to be powered; A secondary coil (3) is disposed outside the primary coil and coaxial with the primary coil, the secondary coil being configured to generate an induced electromotive force when the power supply to the primary coil is interrupted. The center core (41) is disposed inside the primary coil; The outer core (42) is a four-sided ring, with its four parts located on opposite sides of the secondary coil in the axial direction (L) and opposite sides of the secondary coil in the width direction (W) perpendicular to the axial direction. The outer core and the central core together form a closed magnetic circuit in the ignition coil. An igniter (43) includes a switching element configured to selectively enable and interrupt power supply to the primary coil, the igniter being disposed adjacent to the outer core on the axial low-voltage side (L2) of the outer core; The coil housing (5) has an opening (52) on one side of the mounting direction (D) and a bottom (53) on the other side of the mounting direction, the mounting direction being perpendicular to both the axial direction and the width direction, and the coil housing receives all of the primary coil, the secondary coil, the center core, the outer core and the igniter; A connector (24) is mounted to the coil housing to protrude to the outside of the coil housing, the connector having a connector wall portion (241) that forms part of the coil housing on the axial low-pressure side. as well as Electrically insulating fixing resin (6) fills the space in the coil housing to fix the primary coil, the secondary coil, the center core, the outer core, and the igniter in the coil housing while electrically insulating them from each other. in On the inner surface of the connector wall, a connector side rib (26) is formed, protruding from the inner surface of the connector wall to the high-pressure side (L1) in the axial direction. The high-pressure side is opposite to the low-pressure side in the axial direction. The connector side rib has a taper (261) such that the amount of the taper protruding from the inner surface of the connector wall to the axial high-pressure side increases along the mounting direction toward the opening side, and The connector side ribs are configured to press the igniter against the outer core.

8. The ignition coil as claimed in claim 7, wherein an abutment portion (27) is further formed on the inner surface of the connector wall, which abuts against the end of the igniter on the opening side in the mounting direction.

9. The ignition coil as claimed in claim 7 further includes a primary spool (21) on which the primary coil is wound. in The connector and the primary spool are integrally formed as a whole, and The primary spool has an abutment portion (231) that abuts against the end of the igniter on the open side in the mounting direction.

10. The ignition coil of claim 7, wherein the igniter includes an electrical conductor (434) protruding from an end of the igniter on the opening side in the mounting direction to the opening side. The connector includes an electrical conductor (25) configured to face and connect to the electrical conductor of the igniter in the axial direction, and... At least one of the electrical conductors of the igniter and the connector has an elastically deformable portion (435, 253) formed in it.

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