Ignition coil

Abstract

In this ignition coil 2, a protector 16 comprises: a head 28 exposed to the exterior of an internal combustion engine 4; and a barrel 30 that extends downward from a bottom surface of the head 28 and is inserted into a plug hole 6 of the internal combustion engine 4. Provided to this ignition coil 2 is an airway 64 that links the exterior and the plug hole 6 of the internal combustion engine 4. Taking as a reference direction the direction that is perpendicular to a central axis Lf of a mounting hole 20 of a flange section 14 and that goes from the central axis Lf of the mounting hole 20 toward a central axis Lp of the protector 16, a first opening 50 of the airway 64 is provided in a region which is on either an outer surface of a coil assembly 8 or an outer surface of the head 28, located below the flange section 14. The region: extends in the up / down direction; has a centerline, viewed from the reference direction, that overlaps with the central axis Lf of the mounting hole 20; and has a width, viewed from the reference direction, that is the same as that of the mounting hole 20.

Description

[Technical Field]

[0001] The present specification discloses an ignition coil for an internal combustion engine. [Background technology]

[0002] An ignition coil for an internal combustion engine includes a coil assembly containing a high-voltage coil, a protector extending downward from the coil assembly, and a flange portion with a mounting hole. When the ignition coil is installed in an internal combustion engine, the lower portion of the protector is inserted into a spark plug hole of the internal combustion engine. Furthermore, a bolt is inserted into the mounting hole in the flange portion, and the ignition coil is fixed to the internal combustion engine via this bolt.

[0003] When an internal combustion engine is in use, the inside of the spark plug hole becomes hot. The air inside the spark plug hole expands, increasing the pressure inside the spark plug hole. JP 2010-287485 A discloses an ignition device that has a communication passage for discharging the air inside the spark plug hole to the outside. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-287485 A Summary of the Invention [Problem to be solved by the invention]

[0005] Internal combustion engines, like engines installed in vehicles, are sometimes exposed to rainwater and cleaning water. If this water gets into the spark plug hole through the air passage connecting the outside to the spark plug hole, it can interfere with normal combustion. There is a demand for an ignition coil that prevents water from getting into the spark plug hole.

[0006] SUMMARY OF THE INVENTION It is the inventor's intent to provide an ignition coil with an air passage that reduces water ingress. [Means for solving the problem]

[0007] An ignition coil for an internal combustion engine according to one embodiment comprises a coil assembly including a primary coil and a secondary coil, an output portion extending downward from the coil assembly, a protector covering the outer periphery of the output portion and extending downward from the coil assembly, and a flange portion protruding rearward from the coil assembly and having a mounting hole passing through it vertically. The protector comprises a head portion exposed to the outside of the internal combustion engine when the ignition coil is attached to the internal combustion engine, and a tubular portion extending downward from a bottom surface of the head portion and inserted into a spark plug hole of the internal combustion engine. having a first opening and a second opening An airway is provided that connects the outside and the spark plug hole of the internal combustion engine. When a direction perpendicular to the central axis of the mounting hole and a direction from the central axis of the mounting hole toward the central axis of the protector is taken as a reference direction, the airway is located in an area on the outer surface of the coil assembly or the outer surface of the head located below the flange portion, extending in the vertical direction, the center line of which, when viewed from the reference direction, overlaps with the central axis of the mounting hole, and the width of which, when viewed from the reference direction, is the same as the width of the mounting hole. The aforementioned A first opening is provided [Effects of the Invention]

[0008] The ignition coil of this embodiment has an airway connecting the outside to the spark plug hole of the internal combustion engine. When a reference direction is a direction perpendicular to the central axis of the mounting hole in the flange portion and extending from the central axis of the mounting hole toward the central axis of the protector, a first opening of the airway is provided in a region on the outer surface of the coil assembly located below the flange portion or on the outer surface of the head of the protector, extending vertically, whose centerline, when viewed from the reference direction, overlaps with the central axis of the mounting hole, and whose width, when viewed from the reference direction, is the same as that of the mounting hole. When the ignition coil is attached to the internal combustion engine, a bolt is passed through the mounting hole. A bolt or a receiving portion for receiving the bolt is located in front of the region. Water from the outside is blocked by the bolt or receiving portion and therefore does not easily reach the first opening. This ignition coil prevents water from entering the airway. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1(A) is a perspective view showing an ignition coil according to one embodiment, and FIG. 1(B) is a cross-sectional view of the ignition coil of FIG. 1(A). [Figure 2] FIG. 2 is an enlarged cross-sectional view of a part of FIG. 1(B). [Figure 3] FIG. 3 is an enlarged rear view of a portion of the ignition coil of FIG. [Figure 4] FIG. 4(A) is a plan view of the protector of the ignition coil of FIG. 1, and FIG. 4(B) is a bottom view of the protector. [Figure 5] FIG. 5 is an enlarged cross-sectional view of a portion of FIG. [Figure 6] FIG. 6(A) is a rear view showing a part of an ignition coil according to another embodiment, and FIG. 6(B) is a perspective view showing a part of the ignition coil of FIG. 6(A). [Figure 7] FIG. 7 is an enlarged plan view of a part of the protector of the ignition coil of FIG. 6(A). [Figure 8] FIG. 8(A) is a perspective view showing a portion of an ignition coil according to yet another embodiment, FIG. 8(B) is a perspective view showing a portion of a coil assembly of the ignition coil of FIG. 8(A), and FIG. 8(C) is a perspective view showing a portion of a protector of the ignition coil of FIG. 8(A). [Figure 9] FIG. 9 is a perspective view showing a part of an ignition coil according to still another embodiment. [Figure 10] FIG. 10(A) is a perspective view showing a portion of an ignition coil according to yet another embodiment, FIG. 10(B) is a perspective view showing a portion of a coil assembly of the ignition coil of FIG. 10(A), and FIG. 10(C) is a perspective view showing a portion of a protector of the ignition coil of FIG. 10(A). [Figure 11] FIG. 11 is a perspective view showing a part of an ignition coil according to still another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, preferred embodiments will be described in detail with reference to the drawings as appropriate.

[0011] FIG. 1(A) is a perspective view showing an ignition coil 2 according to one embodiment. In FIG. 1, arrow X indicates the front of the ignition coil 2. The opposite of this is rear. Arrow Y indicates the right direction of the ignition coil 2. The opposite of this is left. Arrow Z indicates the upper side of the ignition coil 2. The opposite of this is downward. Note that the directions "forward," "upward," etc. are used in this specification to indicate the relative positional relationships between components of the ignition coil 2, which will be described later. As long as these relative positional relationships are indicated, for example, the direction indicated by "rear" in FIG. 1 may be expressed as "forward" or "rightward."

[0012] FIG. 1(B) is a cross-sectional view of the ignition coil 2 of FIG. 1(A) taken along a plane perpendicular to the left-right direction. FIG. 1(B) also shows an internal combustion engine 4 to which the ignition coil 2 is attached. The internal combustion engine 4 has a plug hole 6, and a portion of the ignition coil 2 is inserted into the plug hole 6. FIG. 2 shows an enlarged view of a portion of FIG. 1(B). The ignition coil 2 includes a coil assembly 8, a connector portion 10, an output portion 12, a flange portion 14, and a protector 16. The internal structures of the coil assembly 8, connector portion 10, and output portion 12 are omitted from FIGS. 1(B) and 2.

[0013] The coil assembly 8 includes a primary coil, a secondary coil, and an iron core (not shown), as well as a case that houses these components. The primary coil is formed by winding wire around the iron core, and the secondary coil is formed by winding wire around the outside of the primary coil. The number of turns of wire in the secondary coil is significantly greater than that of the primary coil. This allows a high voltage to be generated in the secondary coil by changing the current in the primary coil.

[0014] The connector section 10 is located in front of the coil assembly 8. The connector section 10 has an external terminal 18 to which a signal from the outside is input, and an igniter (not shown). The igniter is a switch that controls the conduction and interruption of current in the primary coil by the signal input to the external terminal 18. The operation of the ignition coil 2 is controlled by the signal input to the external terminal 18.

[0015] 2, the output section 12 is located below the coil assembly 8. The output section 12 has a cylindrical shape that extends downward from the coil assembly 8. The high voltage generated in the secondary coil is supplied to a spark plug attached to the internal combustion engine 4 through the output section 12.

[0016] The flange portion 14 protrudes rearward from the coil assembly 8. The flange portion 14 extends perpendicular to the direction in which the output portion 12 extends. The flange portion 14 is formed integrally with the case of the coil assembly 8. A mounting hole 20 is provided in the flange portion 14, penetrating vertically. As shown in FIGS. 1(B) and 2, a receiving portion 22 of the internal combustion engine 4 is located below the mounting hole 20. The receiving portion 22 has a mounting hole 24. When the ignition coil 2 is attached to the internal combustion engine 4, a bolt 25 is passed through the mounting hole 20 in the flange portion 14 and the mounting hole 24 in the receiving portion 22. This bolt 25 is also shown in FIG. 1(B). The ignition coil 2 is fixed to the internal combustion engine 4 by the bolt 25. Note that the bolt 25 is omitted from FIG. 2.

[0017] In this embodiment, the connector portion 10 is located in front of the coil assembly 8, and the flange portion 14 is located behind the coil assembly 8. The flange portion 14 faces the connector portion 10 across the coil assembly 8. The connector portion 10 and the flange portion 14 may be arranged along mutually perpendicular side surfaces of the coil assembly 8. For example, the connector portion 10 may be located on the right side of the coil assembly 8, and the flange portion 14 may be located behind the coil assembly 8. The connector portion 10 may be located in another direction relative to the flange portion 14. In this specification, regardless of the positional relationship between the connector portion 10 and the flange portion 14, the shape of the coil assembly 8, etc., the direction in which the flange portion 14 exists relative to the coil assembly 8 is defined as "rear" of the ignition coil 2. The direction in which the output portion extends relative to the coil assembly 8 is defined as "below" the ignition coil 2.

[0018] The protector 16 is located below the coil assembly 8. The protector 16 has a hole penetrating the interior. The protector 16 is placed over the output section 12. The protector 16 covers the outer periphery of the output section 12. The protector 16 is made of a rubber composition. A preferred example of the material for the protector 16 is silicone rubber. The protector 16 has a head section 28 and a tubular section 30.

[0019] The head 28 is ring-shaped. The head 28 has a hole 32 that passes through the center. The output section 12 is inserted into the hole 32 of the head 28. The output section 12 passes through the hole 32 of the head 28 and extends further downward from the head 28. The inner peripheral surface of the hole 32 of the head 28 is in contact with the outer peripheral surface of the output section 12 without any gap. The top surface 34 of the head 28 is in contact with the bottom surface 36 of the coil assembly 8.

[0020] As shown in Figures 1(B) and 2, when the ignition coil 2 is attached to the internal combustion engine 4, the head 28 is exposed to the outside from the internal combustion engine 4. The head 28 covers the opening of the spark plug hole 6 of the internal combustion engine 4. The outer diameter of the head 28 is larger than the inner diameter of the spark plug hole 6. The inner diameter of the head 28 is smaller than the inner diameter of the spark plug hole 6. As shown in Figure 2, a fitting groove 40 is provided in the bottom surface 38 of the head 28. The fitting groove 40 is ring-shaped (see Figure 4(B)). A ring-shaped protrusion 42 is provided on the top surface of the internal combustion engine 4. As shown in Figure 2, the protrusion 42 of the internal combustion engine 4 is fitted into the fitting groove 40 of the head 28. The head 28 acts as a lid that closes the opening of the spark plug hole 6.

[0021] The cylindrical portion 30 extends downward from the head portion 28. In this embodiment, the cylindrical portion 30 is formed integrally with the head portion 28. The cylindrical portion 30 and the head portion 28 may also be formed separately. The cylindrical portion 30 has a hole 44 that is continuous with the hole 32 of the head portion 28. The outer diameter of the cylindrical portion 30 is smaller than the outer diameter of the head portion 28. The outer diameter of the cylindrical portion 30 is smaller than the inner diameter of the spark plug hole 6. As shown in FIGS. 1(B) and 2, when the ignition coil 2 is mounted on the internal combustion engine 4, the cylindrical portion 30 is inserted into the spark plug hole 6. At this time, a gap exists between an outer peripheral surface 46 of the cylindrical portion 30 and an inner peripheral surface 48 of the internal combustion engine 4 that forms the spark plug hole 6.

[0022] In FIG. 2, the dashed-dotted line Lf represents the central axis of the mounting hole 20. The dashed-dotted line Lp represents the central axis of the protector 16. The central axis Lp of the protector 16 is a line that passes through the center of the hole 32 in the head 28 at the position on the bottom surface 38 of the head 28 and extends in the vertical direction. In FIG. 2, the arrow D is perpendicular to the central axis Lf and represents the direction from the central axis Lf toward the center line Lp. This direction is referred to as the reference direction D. In this embodiment, the reference direction D coincides with the direction X that extends from the rear to the front of the ignition coil 2.

[0023] FIG. 3 shows a portion of the ignition coil 2 as viewed from the reference direction D. In this embodiment, FIG. 3 is a rear view of the ignition coil 2. In this figure, the central axis Lf and the central axis Lp overlap. In FIG. 3, the symbol R represents a region on the outer surface of the coil assembly 8 and the outer surface of the head 28 that is located below the flange portion 14. This region R extends in the vertical direction from the lower end of the flange portion 14 to the lower end of the head 28. When viewed from the reference direction D, the center line Lr of the region R overlaps with the central axis Lf of the mounting hole 20, and the width of the region R is the same as the width of the mounting hole 20. This region R is referred to as the "arrangement region R."

[0024] The ignition coil 2 has an opening 50 in the arrangement region R. Here, "having an opening in the arrangement region R" means that a part or all of the opening 50 is located within the arrangement region R. As will be described later, this opening 50 is a first opening 50 of an airway that the ignition coil 2 has. In the embodiment of FIG. 3, the first opening 50 is located at the end of the head 28 on the coil assembly 8 side. In the embodiment of FIG. 3, the first opening 50 is located on the center line Lr.

[0025] Fig. 4(A) is a plan view of the protector 16. This view shows the top surface 34 of the head 28. Fig. 4(B) is a bottom view of the protector 16. This view shows the bottom surface 38 of the head 28 and the tubular portion 30. Fig. 5 is an enlarged cross-sectional view showing the vicinity of the head 28.

[0026] As shown in FIGS. 4(A) and 5, the upper surface 34 of the head 28 is provided with an outlet groove 52 extending from the first opening 50, a first ring groove 54, and a second ring groove 56. As shown in FIG. 4(A), a connecting groove 58 is further provided on the upper surface 34 of the head 28. The outlet groove 52 connects the first opening 50 and the first ring groove 54. The connecting groove 58 connects the first ring groove 54 and the second ring groove 56. As shown in FIG. 4(A), a hole opening 59 is provided at the bottom of the second ring groove 56. As shown in FIG. 4(B), a hole opening 60 is provided at the bottom surface 38 of the head 28. As shown in FIG. 5, a ventilation hole 62 is provided that penetrates from the bottom of the second ring groove 56 to the bottom surface 38 of the head 28. The opening 60 provided in the bottom surface 38 of the head 28 is a second opening 60 of the airway. In other words, the ignition coil 2 has an air passage 64 that runs from the first opening 50 through the lead-out groove 52, the first ring groove 54, the connecting groove 58, the second ring groove 56, and the ventilation hole 62 to the second opening 60. The air passage 64 is shown by a dotted line in Figures 4(A) and 5.

[0027] As shown in FIG. 4(B), the fitting groove 40 provided in the bottom surface 38 of the head 28 is ring-shaped. The second opening 60 is provided inside the fitting groove 40 and outside the tubular portion 30. As shown in FIG. 5, the second opening 60 is located between the tubular portion 30 and the inner circumferential surface of the internal combustion engine 4 that forms the spark plug hole 6. The second opening 60 is connected to the spark plug hole 6. In other words, the air passage 64 of the ignition coil 2 connects the outside to the spark plug hole 6.

[0028] The effects of this embodiment will be described below.

[0029] The ignition coil 2 of this embodiment is provided with an air passage 64 that connects the outside with the spark plug hole 6 of the internal combustion engine 4. A first opening 50 of the air passage 64 is provided in the arrangement region R. When the ignition coil 2 is attached to the internal combustion engine 4, a bolt 25 is passed through the mounting hole 20 of the flange portion 14. A receiving portion 22 that receives the bolt 25 is located below the mounting hole 20. The outer diameter of the receiving portion 22 is larger than the inner diameter of the mounting hole 20. The receiving portion 22 is located on the front side of the arrangement region R, and the flange portion 14 is located above the arrangement region R. Water from the outside is blocked by the receiving portion 22 and the flange portion 14, making it difficult for it to reach the first opening 50. With this ignition coil 2, water is prevented from entering the air passage 64.

[0030] Note that there may be cases where the receiving portion 22 is not present and the bolt 25 that passes through the mounting hole 20 extends to the top surface of the internal combustion engine. In this case, the bolt 25 is located on the front side of the arrangement region R. Water from the outside is blocked by the bolt 25. By positioning the first opening 50 in the arrangement region R, water from the outside is blocked by the receiving portion 22 or the bolt 25.

[0031] 3, the symbol Wr represents the width of the arrangement region R. From the viewpoint of effectively preventing water from entering the airway 64, the distance between the center of the first opening 50 and the center line Lr is preferably 30% or less of the width Wr, more preferably 20% or less of the width Wr, and even more preferably 10% or less of the width Wr. It is most preferable that the center of the first opening 50 is located on the center line Lr.

[0032] The first opening 50 is preferably located at the end of the head 28 on the coil assembly 8 side, in the placement region R. In this manner, the air passage 64 can be formed by a groove provided in the top surface 34 of the head 28 and a vent hole 62 that penetrates from the bottom of the groove to the bottom surface 38 of the head 28. In this embodiment, the air passage 64 is formed by the lead-out groove 52, the first ring groove 54, the connecting groove 58, the second ring groove 56, and the vent hole 62. To form the air passage 64, it is not necessary to provide a hole that extends horizontally inside the head 28 or the coil assembly 8. This makes it easier to manufacture the ignition coil 2.

[0033] The second opening 60 is preferably located in the bottom surface 38 of the head portion 28. By locating the second opening 60 in the bottom surface 38 of the head portion 28, the length of the vent hole 62 can be shortened, which makes it easier to manufacture the ignition coil 2.

[0034] The position of the second opening 60 is not limited to the bottom surface 38 of the head portion 28. For example, the second opening 60 may be provided in the outer peripheral surface 46 of the tubular portion 30. In this case, for example, the second ring groove and the opening of the vent hole provided in this second ring groove are located above the tubular portion 30. The vent hole extends from the bottom of the second ring groove through the head portion 28, further through a part of the tubular portion 30, and to the outer peripheral surface 46 of the tubular portion 30. The second opening 60 only needs to be provided in a position that connects to the spark plug hole 6.

[0035] Fig. 6(A) is a rear view showing a portion of an ignition coil 70 according to another embodiment, and Fig. 6(B) is a perspective view showing a portion of the ignition coil 70. As shown in Figs. 6(A) and 6(B), the ignition coil 70 includes a coil assembly 72, a flange portion 74, and a protector 76. In the ignition coil 70, a guard 80 is provided around the first opening 78. Aside from the provision of the guard 80, the ignition coil 70 is the same as the ignition coil 2 in Fig. 1.

[0036] Fig. 7 is a plan view showing a portion of the head 82 of the protector 76 of Fig. 6. In this embodiment, the guard 80 protrudes from a side surface 83 of the head 82. The guard 80 is located on both sides of the first opening 78 (in the circumferential direction of the head 82). In this embodiment, the guard 80 is made up of a first portion 80a located on one side of the first opening 78 and a second portion 80b located on the other side of the first opening 78. The first portion 80a and the second portion 80b are each columnar.

[0037] FIG. 7 also shows a cross section 88 of the bolt 86 when the bolt 86, whose outer diameter is the same as the inner diameter of the mounting hole 84 and extends below the first opening 78, is inserted into the mounting hole 84 of the flange portion 74. In reality, the receiving portion 22 of the internal combustion engine 4, which has a larger outer diameter than the bolt 86, is located in front of the mounting hole 84. In other words, this cross section 88 is the smallest cross section of a member that can be located in front of the first opening 78. In FIG. 7, dotted line V1 is a tangent to the outer surface of the bolt 86 that passes through the corner of the first portion 80a that faces the first opening 78, and dotted line V2 is a tangent to the outer surface of the bolt 86 that passes through the corner of the second portion 80b that faces the first opening 78. Neither tangent line V1 nor V2 reaches the first opening 78. In other words, when the ignition coil 70 is viewed from any direction perpendicular to the vertical direction at the same vertical position as the first opening 78, the first opening 78 is hidden behind the bolt 86 or the guard 80. In this specification, this state is referred to as "the first opening 78 being hidden." In other words, the height of the guard 80 (in this embodiment, the height of each of the first portion 80a and the second portion 80b) is determined so that the first opening 78 is hidden.

[0038] The ignition coil 70 of this embodiment is provided with guards 80 that are located on both sides of the first opening 78 and protrude from the side surfaces 83 of the head portion 82. These guards 80 effectively prevent water from entering the first opening 78 from the sides. This ignition coil 70 prevents water from entering the airway.

[0039] As described above, the height of the guard 80 is preferably determined so as to hide the first opening 78. In this way, the guard 80 more effectively prevents water from the outside from reaching the first opening 78. In the ignition coil 70, water is prevented from entering the airway.

[0040] The height of the guard 80 does not have to be determined so as to hide the first opening 78. The height of the guard 80 may be lower or higher than the height determined so as to hide the first opening 78. However, the height of the guard 80 needs to be determined so as not to come into contact with the receiving portion 22.

[0041] The shape of the guard 80 is not limited to the shape shown in FIG. 7. The convexities of the first portion 80a and the second portion 80b may be tapered as they extend outward. Each of the first portion 80a and the second portion 80b may be arc-shaped and protrude from the side surface 83 of the head portion 82. The guard 80 may include a third portion that protrudes from below the first opening 78 and connects the first portion 80a and the second portion 80b. The guard 80 may be ring-shaped and protrude from the side surface 83 of the head portion 82 and the side surface of the coil assembly 72 to surround the first opening 78. The guard 80 may have other shapes. It is sufficient that the guard 80 protrudes from the side surface 83 of the head portion 82 on both lateral sides of the first opening 78.

[0042] Fig. 8(A) is a perspective view showing a portion of an ignition coil 90 according to yet another embodiment, Fig. 8(B) is a perspective view of the ignition coil 90 with a protector 94 removed, and Fig. 8(C) is a perspective view of the removed protector 94. Fig. 8(B) shows a portion of a coil assembly 92 and an output section 96 of the ignition coil 90.

[0043] As shown in Figure 8(B), in this ignition coil 90, a recess 100 that recesses upward is provided at the end of the side surface 99 side of the bottom surface 98 of the coil assembly 92. As shown in Figure 8(C), a protrusion 106 that extends upward is provided at the end of the side surface 105 side of the top surface 104 of the head 102 of the protector 94. As shown in Figure 8(A), when the coil assembly 92 and the protector 94 are assembled, the protrusion 106 is fitted into the recess 100. This ignition coil 90 is the same as the ignition coil 2 of Figure 1, except for having the recess 100 and the protrusion 106 fitted into it.

[0044] In this ignition coil 90, the protrusion 106 of the head 102 is fitted into the recess 100 of the coil assembly 92, preventing the protector 94 from rotating relative to the coil assembly 92 when assembling the coil assembly 92 and the protector 94. This allows the first opening 108 to be accurately positioned relative to the coil assembly 92. Because the case and flange portion 110 of the coil assembly 92 are formed integrally, the first opening 108 can be accurately positioned relative to the central axis Lf of the mounting hole 112 of the flange portion 110. In this ignition coil 90, the first opening 108 can be accurately positioned on the center line Lr of the arrangement region R. In this ignition coil 90, water is prevented from entering the airway.

[0045] Although not shown, in an ignition coil according to yet another embodiment, a downwardly extending protrusion is provided on the side edge of the bottom surface of the coil assembly, and a downwardly recessed recess is provided on the side edge of the top surface of the head of the protector. When the coil assembly and the protector are assembled, the protrusion is fitted into the recess. This ignition coil is the same as the ignition coil 2 in FIG. 1 except for the recess and the protrusion fitted into it. In this ignition coil, the protector is prevented from rotating relative to the coil assembly when the coil assembly and the protector are assembled.

[0046] 9 is a perspective view showing a portion of an ignition coil 120 according to yet another embodiment. In this ignition coil 120, a protrusion 130 provided on the upper side of a head 128 of a protector 126 is fitted into a recess 124 on the bottom surface of a coil assembly 122. In this embodiment, the protrusion 130 of the head 128 and the recess 124 of the coil assembly 122 are provided within the arrangement region R. A first opening 132 is provided in a side surface 131 of the protrusion 130 of the head 128. This ignition coil 120 is the same as the ignition coil 90 in FIG. 8 except that the protrusion 130 of the head 128 and the recess 124 of the coil assembly 122 are provided within the arrangement region R and the first opening 132 is provided in the side surface 131 of the protrusion 130.

[0047] In this ignition coil 120, a first opening 132 is provided on a side surface 131 of a protrusion 130 of a head portion 128 that fits into a recess 124 of the coil assembly 122. This allows the first opening 132 to be accurately positioned with respect to the coil assembly 122. The first opening 132 can be accurately positioned with respect to the central axis Lf of the mounting hole 136 of the flange portion 134. In this ignition coil 120, water is prevented from entering the airway.

[0048] Fig. 10(A) is a perspective view showing a portion of an ignition coil 140 according to yet another embodiment, Fig. 10(B) is a perspective view of the ignition coil 140 with a protector 144 removed, and Fig. 10(C) is a perspective view of the removed protector 144. Fig. 10(B) shows a portion of a coil assembly 142 and an output section 146 of the ignition coil 140.

[0049] As shown in FIG. 10(A), in this embodiment, the first opening 148 is provided in the side surface 143 of the coil assembly 142. The first opening 148 is located at the end of the side surface 143 of the coil assembly 142 on the head 150 side of the protector 144. As shown in FIG. 10(B), an outlet groove 154 extending from the first opening 148 is formed in the bottom surface 152 of the coil assembly 142. Although not shown, a first ring groove, a connecting groove, and a second ring groove are formed in the top surface 156 of the head 150, similar to the head 28 in FIG. 4(A). Furthermore, an air vent is provided extending from the bottom of the second ring groove to the bottom surface 158 of the head 150. The outlet groove 154 provided in the bottom surface 152 of the coil assembly 142 is connected to the first ring groove. In this embodiment, the outlet groove 154, the first ring groove, the connecting groove, the second ring groove, and the air vent form an airway.

[0050] In this embodiment, the first opening 148 is located at the end of the side surface 143 of the coil assembly 142 on the head 150 side, in the placement region R. In this manner, the air passage can be formed by a groove provided in the bottom surface 152 of the coil assembly 142, a groove provided in the top surface 156 of the head 150, and a vent hole that passes through from the bottom of the groove to the bottom surface 158 of the head 150. To form the air passage, it is not necessary to provide a hole that extends horizontally inside the head 150 or the coil assembly 142. This makes it easier to manufacture the ignition coil 140.

[0051] In this embodiment, the first opening 148 is provided in the side surface 143 of the coil assembly 142. The position of the first opening 148 relative to the central axis Lf of the mounting hole 162 in the flange portion 160 is not affected by rotation of the protector 144 relative to the coil assembly 142. The first opening 148 can be accurately positioned relative to the central axis Lf of the mounting hole 162 in the flange portion 160. In this ignition coil 140, the first opening 148 can be accurately positioned on the center line Lr of the arrangement region R. In this ignition coil 140, water is prevented from entering the airway.

[0052] Although not shown, in an ignition coil according to yet another embodiment, a downwardly extending protrusion is provided on the side edge of the bottom surface of the coil assembly, a downwardly recessed recess is provided on the side edge of the top surface of the head of the protector, and a first opening is provided on the side of the protrusion of the coil assembly. When the coil assembly and the protector are assembled, the protrusion is fitted into the recess. This ignition coil is the same as ignition coil 140 in Figure 10, except for the recess, the fitted protrusion, and the first opening.

[0053] 11 is a perspective view showing a part of an ignition coil 170 according to still another embodiment. In this ignition coil 170, the first opening is formed on the side of the coil assembly 172 in the arrangement region R. Face, and is located at the end of the protector 176 on the head 178 side. A guard 174 is provided around the first opening. This ignition coil 170 is the same as the ignition coil 140 in FIG. 10 except that the coil assembly 172 is provided with the guard 174.

[0054] In this embodiment, the guard 174 is attached to the side of the coil assembly 172. Face The guards 174 are located on both sides of the first opening. In this embodiment, the guards 174 are made up of a first portion 174a located on one side of the first opening and a second portion 174b located on the other side of the first opening.

[0055] The shape of the guard 174 is not limited to the shape shown in Fig. 11. The first part 174a and the second part 174b are Face The guard 174 may have an arcuate shape that protrudes from above the first opening. The guard 174 may have a third portion that protrudes from above the first opening and is continuous with the first portion 174a and the second portion 174b. visit The guard 174 may be a ring-shaped member that protrudes from the side surface 180 of the head 178 and surrounds the first opening. The guard 174 may have other shapes. The guard 174 is attached to the side of the coil assembly 172 on both sides of the first opening. Face It is enough if it stands out.

[0056] In the embodiments described above, the first opening is provided on either the side surface of the head or the side surface of the coil assembly. The first opening may be provided across both the side surface of the head and the side surface of the coil assembly. In this case, an extraction groove extending from the first opening is provided on the upper surface of the head, and an extraction groove extending from the first opening is provided on the lower surface of the coil assembly.

[0057] As described above, according to this embodiment, the intrusion of water into the air passage of the ignition coil is suppressed, and the superiority of this embodiment is clear.

[0058] [Disclosure items] The following items are disclosures of preferred embodiments.

[0059] [Item 1] An ignition coil for an internal combustion engine, a coil assembly including a primary coil and a secondary coil; an output portion extending downward from the coil assembly; a protector covering an outer periphery of the output portion and extending downward from the coil assembly; and a flange portion protruding rearward from the coil assembly and having a mounting hole passing through in the vertical direction, the protector comprises a head portion that is exposed to the outside of the internal combustion engine when the ignition coil is attached to the internal combustion engine, and a tubular portion that extends downward from a bottom surface of the head portion and is inserted into a spark plug hole of the internal combustion engine, The ignition coil having a first opening and a second opening an air passage is provided that connects the outside with the spark plug hole of the internal combustion engine; When a direction perpendicular to the central axis of the mounting hole and a direction from the central axis of the mounting hole toward the central axis of the protector is defined as a reference direction, The region on the outer surface of the coil assembly or the outer surface of the head located below the flange portion extends in the vertical direction, the center line of which, when viewed from the reference direction, overlaps with the center axis of the mounting hole, and the width of which, when viewed from the reference direction, is the same as the width of the mounting hole. The aforementioned an ignition coil having a first opening;

[0060] [Item 2] The underside of the head is The aforementioned Item 1. The ignition coil according to item 1, further comprising a second opening.

[0061] [Item 3] 3. The ignition coil according to item 1 or 2, further comprising guards protruding from the side surfaces of the head or the coil assembly on both sides of the first opening.

[0062] [Item 4] When a bolt having the same outer diameter as the inner diameter of the mounting hole and extending to a position below the first opening is mounted in the mounting hole, the first opening is positioned at the same vertical position as the first opening and extends downward from any direction perpendicular to the vertical direction when the ignition coil is viewed from the same vertical position as the first opening. bolt Alternatively, the height of the guard is determined so that the ignition coil is hidden behind the guard.

[0063] [Item 5] a protrusion extending upward from the upper surface of the head is provided at a side edge of the upper surface of the head, 5. The ignition coil according to any one of items 1 to 4, wherein a recess into which the protrusion fits is provided on a bottom surface of the coil assembly.

[0064] [Item 6] 6. The ignition coil according to item 5, wherein the first opening is formed in a side surface of the projection.

[0065] [Item 7] the first opening is provided on a side surface of the head at an end on the coil assembly side, 7. The ignition coil according to any one of items 1 to 6, wherein the airway is formed by a groove provided on the upper surface of the head and connected to the first opening, and a hole extending from the bottom of the groove to the second opening.

[0066] [Item 8] 8. The ignition coil according to any one of items 1 to 7, wherein the first opening is provided on the end of the side of the coil assembly on the head side.

[0067] [Item 9] The underside of the head is The aforementioned a second opening is provided; Item 9. The ignition coil according to item 8, wherein the airway is formed by a first groove provided in the bottom surface of the coil assembly and communicating with the first opening, a second groove provided in the top surface of the head and communicating with the first groove, and a hole extending from the bottom of the second groove to the second opening.

[0068] [Item 10] 10. A composite body of an ignition coil and an internal combustion engine, comprising: the ignition coil according to any one of items 1 to 9; and an internal combustion engine having a plug hole into which the cylindrical portion of the protector of the ignition coil is inserted. [Industrial Applicability]

[0069] The ignition coil described above is used in various internal combustion engines. [Explanation of symbols]

[0070] 2, 70, 90, 120, 140, 170... Ignition coil 4. Internal combustion engine 6. Plug hole 8, 72, 92, 122, 142, 172 Coil assembly 10 Connector part 12, 96, 146... Output section 14, 74, 110, 134, 160... Flange part 16, 76, 94, 126, 144, 176... Protector 20, 84, 112, 136, 162: Mounting holes on flange 22 Receiving part 24 Mounting hole for receiving part 28, 82, 102, 128, 150, 178...Head 30...Cylinder part 32 Head hole 34, 104, 156...Top of head 36, 98... Bottom of coil assembly 38, 158... Bottom of head 40···Mating groove 42. Protrusion of internal combustion engine 44....Cylinder hole 46....Outer surface of cylindrical portion 48...Inner peripheral surface 50, 78, 108, 132, 148...first opening 52, 154... Drawer groove 54 First ring groove 56 Second ring groove 58 Connecting groove 60...Second opening 62 Ventilation hole 64. Airway 80, 174... Guard 83, 105, 180... Side of head 25, 86 volts 88...cross section 99, 14 3· Side of the coil assembly 100, 124... recess 106, 130 Head protrusion 131... Side of head protrusion

Claims

1. An ignition coil for an internal combustion engine, a coil assembly including a primary coil and a secondary coil; an output portion extending downward from the coil assembly; a protector covering an outer periphery of the output portion and extending downward from the coil assembly; and a flange portion protruding rearward from the coil assembly and having a mounting hole passing through in the vertical direction, the protector comprises a head portion that is exposed to the outside of the internal combustion engine when the ignition coil is attached to the internal combustion engine, and a tubular portion that extends downward from a bottom surface of the head portion and is inserted into a spark plug hole of the internal combustion engine, the ignition coil is provided with an air passage having a first opening and a second opening and connecting the outside to the spark plug hole of the internal combustion engine; When a direction perpendicular to the central axis of the mounting hole and a direction from the central axis of the mounting hole toward the central axis of the protector is defined as a reference direction, an ignition coil, wherein the first opening of the airway is provided in a region on the outer surface of the coil assembly or the outer surface of the head located below the flange portion, the region extending in the vertical direction, the center line of which, when viewed from the reference direction, overlaps with the central axis of the mounting hole, and the width of which, when viewed from the reference direction, is the same as the width of the mounting hole.

2. The ignition coil according to claim 1 , wherein the second opening of the airway is provided on a bottom surface of the head.

3. The ignition coil according to claim 1 or 2, further comprising guards protruding from the side surfaces of the head portion or the coil assembly on both sides of the first opening.

4. 4. The ignition coil according to claim 3, wherein the height of the guard is determined so that, when a bolt having an outer diameter equal to the inner diameter of the mounting hole and extending below the first opening is attached to the mounting hole, the first opening is hidden behind the bolt or the guard when the ignition coil is viewed from any direction perpendicular to the up-down direction at the same vertical position as the first opening.

5. a protrusion extending upward from the upper surface of the head is provided at a side edge of the upper surface of the head, 3. The ignition coil according to claim 1, wherein a recess into which the protrusion is fitted is provided on a bottom surface of the coil assembly.

6. The ignition coil according to claim 5 , wherein the first opening is formed in a side surface of the projection.

7. the first opening is provided on a side surface of the head at an end on the coil assembly side, 3. The ignition coil according to claim 1, wherein the airway is formed by a groove provided on the upper surface of the head and connected to the first opening, and a hole extending from the bottom of the groove to the second opening.

8. 3. The ignition coil according to claim 1, wherein the first opening is provided at the end of the side surface of the coil assembly on the head side.

9. The second opening of the airway is provided on the bottom surface of the head, 9. The ignition coil according to claim 8, wherein the air passage is formed by a first groove provided in the bottom surface of the coil assembly and communicating with the first opening, a second groove provided in the top surface of the head and communicating with the first groove, and a hole extending from the bottom of the second groove to the second opening.

10. 3. A composite body of an ignition coil and an internal combustion engine, comprising: the ignition coil according to claim 1 or 2; and an internal combustion engine having a plug hole into which the cylindrical portion of the protector of the ignition coil is inserted.

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