JP4059013B2 - Ignition coil - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ignition coil, and more particularly to an ignition coil directly mounted in a plug hole of an engine.
[0002]
[Prior art]
  FIG.Fig. 2 shows an enlarged view of the vicinity of the central core portion of the conventional ignition coil. As shown in the figure, the central core portion 100 includes a central core 101, an upper elastic member 102, a lower elastic member 103, and an elastic tube 104. The central core 101 is formed by laminating strip-shaped thin silicon steel plates 112. The secondary spool 105 is disposed on the outer peripheral side of the central core portion 100. A secondary winding 106 is wound around the outer peripheral surface of the secondary spool 105.
[0003]
The connector portion 107 is disposed above the central core portion 100 and the secondary spool 105. An alignment rib 108 is erected from the lower end surface 111 of the connector portion 107. The alignment rib 108 is inserted from above between the upper end inner peripheral surface of the secondary spool 105 and the upper end outer peripheral surface of the center core portion 100.
[0004]
Each member is housed in a housing which is an outer shell of an ignition coil. The housing is filled with epoxy resin. Specifically, the epoxy resin is injected into a vacuumed housing. And it penetrates between each member and hardens. The epoxy resin ensures insulation between the members. Moreover, each member is fixed.
[0005]
Epoxy resin flows into the inner peripheral side of the secondary spool 105 from the lower end opening 109 as shown by the white arrow in the figure. The infused epoxy resin flows into the inner peripheral side of the central core portion 100 from a portion not covered with the elastic tube 104.
[0006]
[Problems to be solved by the invention]
By the way, the linear expansion coefficient of each member arrange | positioned in a housing, such as the center core part 104, the secondary spool 105, and the secondary winding 106, differs, respectively. However, each member is joined by an epoxy resin. Further, the ignition coil repeats heating and cooling as the engine is operated and stopped. Therefore, when each member having a different linear expansion coefficient repeats expansion and contraction due to a temperature change of the ignition coil, the epoxy resin receives thermal stress. Therefore, if voids (bubbles) remain in the epoxy resin, thermal stress concentrates on the bubbles, and cracks may occur, leading to voltage leakage. In addition, since the insulating dimension of the epoxy resin is insufficient by the volume of the bubbles, it is possible that problems such as dielectric breakdown occur. For this reason, it is better to remove voids in the epoxy resin as much as possible before the epoxy resin is cured.
[0007]
Here, the assembly of the central core portion 100 is performed in the atmosphere. That is, first, the silicon steel plate 112 is laminated to produce the central core 101, then the upper elastic member 102 and the lower elastic member 103 are attached to the upper and lower ends of the central core 101, and finally these members are covered with the elastic tube 104. A series of assembly operations is performed in the atmosphere. For this reason, a void is unavoidably present in the central core portion 100.
[0008]
However, conventionally, there has been no means for positively removing voids in the central core portion 100. For this reason, even if the epoxy resin is injected, there is a possibility that voids are not sufficiently substituted in the central core portion 100 and voids remain in the central core portion 100.
[0009]
The ignition coil of the present invention has been completed in view of the above problems. Accordingly, an object of the present invention is to provide an ignition coil that can easily remove voids inherent in the central core portion.
[0010]
[Means for Solving the Problems]
(1) In order to solve the above-described problem, an ignition coil according to the present invention includes a housing, a rod-shaped central core disposed substantially at the center of the housing, an upper elastic member disposed above the central core, A central core portion having an elastic tube covering the central core and the upper elastic member from the outer peripheral side, and a tubular primary wound around the primary winding disposed in the outer peripheral side of the central core portion in the housing A spool, a cylindrical secondary spool disposed on the outer peripheral side of the central core portion in the housing and wound with a secondary winding; and disposed above the central core portion, the primary spool and the secondary spool Among the next spools, there is an alignment rib that is inserted from above between the inner peripheral spool disposed on the inner peripheral side and the central core portion, and performs alignment of the central core portion in the housing. Connector part and inside the housing A resin insulation material that is injected and cured to ensure insulation between the members, and the upper elastic member has a void removal passage that vertically penetrates the upper elastic member, The void removal passage is connected to the connector portion.Between the lower surface and the upper end surface of the central coreThe connection void removal passage communicates with the connection void removal passage formed on the central core, and the connection void removal passage is above the central core and follows a path away from a member having a lower potential than the central core,The portion where the connecting void removal passage communicates with the upper portion of the connector portion is provided only in the direction in which the low potential member is separated from the central core axis, and the location is outside the outer peripheral surface of the central core and from the upper end surface of the central core. Is aboveIt is characterized by that.
[0011]
That is, the ignition coil according to the present invention has a void removal passage disposed in the upper elastic member. If a void removal passage is arranged in the upper elastic member, for example, a void existing in a gap between the elastic tube and the central core can be removed relatively easily.
[0012]
Further, when the void removal passage is arranged in the upper elastic member, the void can be quickly extracted as compared with the case where the void removal passage is arranged only in the lower elastic member 103 shown in FIG.
[0013]
  The connector portion is configured to have a connection void removal passage communicating with the void removal passage. AboveFIG.As shown, the inner peripheral side of the alignment rib 108 has a cup shape that opens downward. Therefore, the inner circumferential side gap of the alignment rib 108 is formed in a bag path shape upward. The exit of the void removal passage is open to this inner peripheral side gap. The void staying in the inner peripheral side gap can be removed through the gap between the outer peripheral surface of the alignment rib 108 and the upper peripheral surface of the secondary spool 105. However, since the inner circumferential gap is narrow, the void is difficult to move.
[0014]
Therefore, in this configuration, a connecting void removal passage having an inlet in the inner circumferential side gap is arranged in the connector portion. According to this configuration, voids staying in the inner circumferential gap can be removed more quickly.
[0015]
  furtherThe connecting void removal path is located above the central core and follows a path separated from a member having a lower potential than the central core;Has become. Here, the low-potential member includes an igniter primary terminal, secondary terminal, ground terminal, power supply terminal, igniter heat sink, and the like. For example, as shown in FIG. In an ignition coil having a structure in which the wire is on the inner peripheral side of the primary winding and the central core is not grounded, when the secondary winding generates a voltage of about 30 kV, the secondary winding and the central core This means that the central core is charged to a high voltage of about 10 to 15 kV and becomes a high potential due to the capacitive coupling between them, and it means a member having a low potential with respect to the potential.
[0016]
The connection void removal passage is filled with a resin insulating material after the void has passed. Then, the resin insulating material is cured in the connection void removal passage. Here, the linear expansion coefficient of a material such as PBT forming the connector portion is different from the linear expansion coefficient of a resin insulating material such as an epoxy resin. Therefore, there is a possibility that the connector part and the resin insulating material are peeled off on the inner peripheral surface of the connection void removal passage due to the difference in the linear expansion coefficient. When the connector portion and the resin insulating material are peeled off, the voltage of the central core leaks to a member having a lower voltage than the central core along the peeled surface, which may cause an abnormal operation or dielectric breakdown.
[0017]
In this respect, the present configuration is formed with a connecting void removal passage away from the low potential member. Therefore, even if the resin insulating material is hardened in the connection void removal passage and the connector portion and the resin insulation peel off on the inner peripheral surface of the connection void removal passage, the separation surface is separated from the low potential member. For this reason, according to this structure, there is little possibility that a voltage leak will occur.
[0018]
In addition, the connecting void removal passage may not be able to be separated from the low potential member due to the shape and size of the coil, but in that case, from the upper end of the central core, the void removal passage is passed through. In order to increase the distance to reach the low potential member, it is preferable to make the void removal path into a labyrinth or to provide a rib in the middle to increase the distance. . The total length of the void removal passage is preferably about 10 to 30 mm.
[0019]
  Moreover, the said connection void removal channel | path is the structure connected to the upper direction of the said connector part.Further, the portion where the connecting void removal passage communicates with the upper portion of the connector portion is provided only in the direction of separating the low potential member from the central core axis, and the portion is outside the outer peripheral surface of the central core and on the central core. It is above the end face.Only the connector portion is disposed above the central core portion. For this reason, according to this structure, a void can be moved to the exterior of an ignition coil only by a connection void extraction channel | path. Further, according to this configuration, the length of the connecting void removal passage can be relatively short. Further, the void is likely to move upward due to buoyancy. For this reason, according to this structure, a void can be removed more rapidly.
[0020]
  (2) Further, in order to solve the above-mentioned problem, the ignition coil of the present invention is the same as that of the first aspect of the invention of claim 2 except for the configuration of the connecting void removal passage. That is,The connection void removal passage communicates with the outer peripheral side of the inner peripheral spool;Has become. On the outer peripheral side of the inner peripheral side spool, there is no bag path-like clearance upward. That is, the outer peripheral side of the inner peripheral spool is opened upward. Therefore, if the outlet of the connection void removal passage is extended to the outer peripheral side of the inner peripheral side spool, the void coming out of the outlet can be moved to the outside of the ignition coil relatively easily. For this reason, according to this structure, a void can be removed comparatively easily.
[0021]
  (3) In the inventions of claims 1 and 2,Preferably, the central core portion includes a lower elastic member below the central core, the elastic tube covers the central core, the upper elastic member, and the lower elastic member from the outer peripheral side, and the lower elastic member is It is better to have an auxiliary void removal passage that penetrates the lower elastic member in the vertical direction. That is, in this configuration, the void removal passage is disposed at the upper end of the central core portion, and the auxiliary void removal passage is disposed at the lower end of the central core portion. According to this configuration, the resin insulating material in the central core portion is improved. For this reason, a void can be extracted more rapidly.
[0022]
  (4)Preferably, the central core is a composite central core formed by joining a plurality of magnetic members. When the central core is a composite central core formed by bonding, for example, a silicon steel plate or cement wire, the amount of voids in the central core portion is larger than when the central core is a single body. Therefore, the ignition coil of the present invention excellent in void removal is particularly suitable for implementation as an ignition coil having a composite central core with a large amount of voids.
[0023]
  (5)Preferably, the inner peripheral spool includes a core support rib that is erected from an upper surface of the bottom wall of the inner peripheral spool and that supports a lower end surface of the central core portion, and is divided by the core support rib. The gap between the lower end surface of the central core portion and the lower end surface of the central core portion is preferably set to 0.7 mm or more and 2.0 mm or less.
[0024]
As shown in FIG. 10, the core support rib 110 is erected on the upper surface of the bottom wall of the inner peripheral side spool (secondary spool) 105. The lower end surface of the central core portion 100 is supported by the core support rib 110. And the clearance gap between the bottom wall upper surface of the inner peripheral side spool 105 and the lower end surface of the center core part 100 is a flow path of the resin insulating material (epoxy resin). On the other hand, the upper end surface of the central core portion 100 is in contact with the lower end surface 111 of the connector portion 107.
[0025]
Here, the upper elastic member 102, the lower elastic member 103, and the elastic tube 104 have elasticity. Therefore, the central core portion 100 is sandwiched and fixed in a compressed state between the lower end surface 111 and the core support rib 110.
[0026]
However, when the central core portion 100 is compressed, the core support rib 110 bites into the lower end surface of the central core portion 100. And the clearance gap between the bottom wall upper surface of the inner peripheral side spool 105 and the lower end surface of the center core part 100 will become narrow. In other words, it becomes difficult for the resin insulating material to flow into the gap between the inner peripheral surface of the inner peripheral side spool 105 and the outer peripheral surface of the central core portion 100. If the void interposed in the gap between the inner peripheral surface of the inner peripheral side spool 105 and the outer peripheral surface of the central core portion 100 is not replaced with the resin insulating material, there is a possibility that dielectric breakdown due to this void occurs.
[0027]
In this configuration, the clearance between the inner peripheral spool bottom wall upper surface and the central core lower end surface is set to 0.7 mm or more. The reason is that if the gap is less than 0.7 mm, the resin insulating material is less likely to flow into the gap between the inner peripheral surface of the inner peripheral spool and the outer peripheral surface of the central core, and the inner peripheral spool inner peripheral surface and the central core portion. This is because voids may remain in the gap with the outer peripheral surface.
[0028]
Moreover, in this structure, the clearance gap between the inner peripheral side spool bottom wall upper surface and the center core part lower end surface is set to 2.0 mm or less. The reason is that if the gap exceeds 2.0 mm, the axial length of the ignition coil becomes long and the plug hole mounting property is lowered.
[0029]
  (6)Preferably, the elastic tube forms the lower end surface of the central core part, and the elastic modulus of the elastic tube is preferably set to 1000 MPa or more and 1500 MPa or less.
[0030]
When the elastic tube forms the lower end surface of the central core portion, it is the elastic tube that is directly supported by the core support rib. Therefore, increasing the longitudinal elastic modulus of the elastic tube can suppress the biting of the core support rib into the elastic tube. And the clearance gap between an inner peripheral side spool bottom wall upper surface and a center core part lower end surface can be ensured widely.
[0031]
In this configuration, the longitudinal elastic modulus of the elastic tube is set to 1000 MPa or more. The reason is that when the longitudinal elastic modulus is less than 1000 MPa, the amount of biting into the elastic tube of the core support rib increases.
[0032]
In this configuration, the elastic modulus of the elastic tube is set to 1500 MPa or less. The reason for this is that if the longitudinal elastic modulus exceeds 1500 MPa, the elasticity of the elastic tube cannot absorb the thermal deformation of, for example, a resin insulating material that accompanies operation and stoppage of the engine, and a malfunction may occur in the ignition coil. It is.
[0033]
  (7) Moreover, in order to solve the said subject, the ignition coil of Claim 7 is arrange | positioned in the housing, the approximate center in this housing, a rod-shaped center core, the upper end of this center core, and the outer peripheral side. A central core portion having an elastic tube for covering, a cylindrical primary spool disposed on the outer peripheral side of the central core portion and wound with a primary winding in the housing, and the central core portion in the housing. A cylindrical secondary spool disposed on the outer peripheral side and wound with a secondary winding, and disposed above the central core portion, and disposed on the inner peripheral side of the primary spool and the secondary spool. A connector part inserted from above between the inner circumferential spool and the central core part and having an alignment rib for aligning the central core part in the housing, and injected into the housing and cured. Ensure insulation between components A ignition coil consisting comprises a resin insulating material, and the elastic tube has a void vent passage through the upper end of the elastic tube in the vertical direction, the void vent passage, said connector portionBetween the lower surface and the upper end surface of the central coreThe connection void removal passage communicates with the connection void removal passage formed on the central core, and the connection void removal passage is above the central core and follows a path away from a member having a lower potential than the central core,The portion where the connecting void removal passage communicates with the upper portion of the connector portion is provided only in the direction in which the low potential member is separated from the central core axis, and the location is outside the outer peripheral surface of the central core and from the upper end surface of the central core. It is the upper part.
  The ignition coil according to claim 8 has the same configuration as that of claim 7, wherein the connecting void removal passage is above the central core and follows a path away from a member having a lower potential than the central core. , It communicates with the outer peripheral side of the inner peripheral spool.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the ignition coil according to the present invention will be described.
[0038]
(1) First embodiment
First, the structure of the ignition coil of this embodiment is demonstrated. FIG. 1 is a sectional view in the axial direction of the ignition coil according to the present embodiment. The ignition coil 1 is housed in a plug hole (not shown) formed for each cylinder in the upper part of the engine block. Further, as will be described later, the ignition coil 1 is connected to a spark plug (not shown) on the lower side in the drawing.
[0039]
The ignition coil 1 includes a housing 2. The housing 2 is made of resin and has a stepped cylindrical shape whose diameter increases upward. A wide-mouthed portion 20 is formed at the upper end of the housing 2 whose diameter has been increased. A cutout window 21 is formed in a part of the side wall of the wide opening 20.
[0040]
Inside the housing 2, the central core portion 5, the primary spool 3, the primary winding 30, the secondary spool 4 and the secondary winding 40 are accommodated. The secondary spool is included in the inner peripheral spool of the present invention.
[0041]
Of these, the central core portion 5 includes a composite central core 54, an upper elastic member 50 a, a lower elastic member 50 b, and a heat shrinkable tube 52. The heat shrinkable tube 52 is included in the elastic tube of the present invention.
[0042]
The composite central core 54 is formed by laminating strip-shaped silicon steel plates (not shown) having different widths in the diameter direction, and has a rod shape. The silicon steel plate is included in the magnetic member of the present invention. The upper elastic member 50a is made of a single foam sponge and has a cylindrical shape. The upper elastic member 50 a is disposed at the upper end of the composite central core 54. The upper elastic member 50a is formed with a void removal passage 9 that penetrates the upper elastic member 50a in the vertical direction. The lower elastic member 50b is made of silicon rubber and has a cylindrical shape. The lower elastic member 50 b is disposed at the lower end of the composite central core 54. The lower elastic member 50b is provided with an auxiliary void removal passage 90 that penetrates the lower elastic member 50b in the vertical direction. The heat shrinkable tube 52 is made of resin that shrinks when heated. The heat-shrinkable tube 52 covers the composite central core 54, the upper elastic member 50a, and the lower elastic member 50b.
[0043]
The secondary spool 4 is made of resin and has a bottomed cylindrical shape. The secondary spool 4 is disposed coaxially with the central core portion 5 and adjacent to the outer peripheral side of the central core portion 5. The secondary winding 40 is wound around the outer peripheral surface of the secondary spool 4. Further, a spool side engaging claw 41 is erected on the upper end surface of the secondary spool 4. A total of three spool-side engaging claws 41 are arranged at 90 ° intervals in the circumferential direction. A core support rib (not shown) is erected from the upper surface of the bottom wall of the secondary spool 4. A total of 12 core support ribs are arranged radially on the upper surface of the bottom wall of the secondary spool 4. The core support rib supports the lower end surface of the central core portion 5, that is, the lower end surface of the heat shrinkable tube 52.
[0044]
The primary spool 3 is arranged coaxially with the secondary spool 4 and adjacent to the outer peripheral side of the secondary spool 4. The primary winding 30 is wound around the outer peripheral side of the primary spool 3. A cylindrical outer core 31 with a slit penetrating in the longitudinal direction is disposed on the outer peripheral side of the primary winding 30.
[0045]
The epoxy resin 8 is interposed between the members arranged in the housing 2. The epoxy resin 8 penetrates between the above members and is cured by injecting an epoxy prepolymer and a curing agent into the housing 2 evacuated from the wide opening portion 20. The epoxy resin 8 is included in the resin insulating material of the present invention.
[0046]
The connector portion 6 is disposed in the wide mouth portion 20 of the housing 2. The connector unit 6 includes a connector 64 and an igniter 65.
[0047]
The connector 64 is made of PBT and includes a pedestal portion 640 and a rectangular tube portion 641. The rectangular tube portion 641 is disposed so as to protrude from the cutout window 21 to the outside of the housing 2. A plurality of terminals 642 are arranged on the rectangular tube portion 641.
[0048]
The pedestal portion 640 is disposed substantially at the center of the wide mouth portion 20. The pedestal portion 640 includes a substrate (not shown) formed integrally with the rectangular tube portion 641 and a press-fitting plate (not shown) press-fitted into the substrate. The pedestal portion 640 will be described in detail later. From the lower end surface 62 of the press-fitting plate of the pedestal portion 640, an alignment rib 63 and a connector portion side engaging claw 66 are erected. The alignment rib 63 has a ring shape. The alignment rib 63 is interposed between the central core portion 5 and the secondary spool 4 from above. Further, a total of three connector portion side engaging claws 66 are arranged at 90 ° intervals in the circumferential direction. The connector side engagement claw 66 is locked to the spool side engagement claw 41. Further, a connecting void removal passage 91 is extended in the radial direction on the press-fitting plate of the pedestal 640. The connection void removal passage 91 communicates with the upper portion of the pedestal portion 640. The connecting void passage 91 will be described in detail later.
[0049]
The igniter 65 is formed by covering a power transistor or an electric circuit with a mold resin. The igniter 65 is mounted on the pedestal 640.
[0050]
The high-pressure tower unit 7 is disposed below the housing 2. The high-pressure tower unit 7 includes a tower housing 70, a high-pressure terminal 71, a spring 72, and a plug cap 73.
[0051]
The tower housing 70 is made of resin and has a cylindrical shape. A boss portion 74 that protrudes upward is formed in the middle on the inner peripheral side of the tower housing 70. The high-pressure terminal 71 has a cup shape having an opening 76 below. A boss 74 is inserted into the opening 76. Further, a convex portion 75 protruding upward from the center of the upper end surface of the high voltage terminal 71 is disposed. The convex portion 75 is inserted into the lower end opening 42 of the secondary spool 4.
[0052]
The spring 72 has a spiral shape. The upper end of the spring 72 is fixed to the opening 76 of the high-pressure terminal 71. A spark plug (not shown) is in elastic contact with the spring 72.
[0053]
The plug cap 73 is made of rubber and has a cylindrical shape. The plug cap 73 is mounted on the lower end portion of the tower housing 70. On the inner peripheral side of the plug cap 73, a spark plug is press-fitted and elastically contacted.
[0054]
Next, the movement when the ignition coil 1 of the present embodiment is energized will be described. The control signal is transmitted from the connector 64 to the primary winding 30 via the igniter 65. A high voltage is generated in the secondary winding 40 by the mutual induction action by the control signal. The high voltage generated in the secondary winding 40 is transmitted to the spark plug via the high voltage terminal 71 and the spring 72. This high voltage causes a spark in the spark plug gap.
[0055]
Next, the movement of the ignition coil according to this embodiment when the epoxy resin is injected will be described. FIG. 2 shows an enlarged view of the vicinity of the central core portion of the ignition coil of the present embodiment. FIG. 3 shows a top view of the ignition coil of the present embodiment. In FIG. 3, the igniter is omitted. As shown in these drawings, the pedestal portion 640 includes a substrate 643 and a press-fit plate 644 that is press-fitted into the substrate. The press-fitting plate 644 has a disk shape. The connection void removal passage 91 extends in the radial direction of the press-fit plate 644. The connection void removal passage 91 communicates the inner peripheral side of the alignment rib 63 and the upper end surface of the pedestal portion 640. The connection void removal passage 91 extends away from the terminal 642.
[0056]
The epoxy resin flows into the inner peripheral side of the secondary spool 4 through a gap between the lower end opening 42 of the secondary spool 4 and the high-pressure terminal (not shown) as indicated by the white arrow in FIG.
[0057]
Part of the epoxy resin that has flowed into the inner peripheral side of the secondary spool 4 penetrates into the central core portion 5 through the auxiliary void removal passage 90. Then, the permeated epoxy resin pushes upward the void 10 interposed in the gap between the composite central core 54 and the heat shrinkable tube 52 or the gap between the silicon steel plates 540, for example. The void 10 pushed upward is removed from the central core portion 5 through the void removal passage 9. And the void 10 moves to the upper end surface of the base part 640 via the connection void extraction channel | path 91 as shown by the arrow in a figure. Then, the void 10 moves to the outside of the ignition coil through a gap between the upper end surface of the base portion 640 and the lower end surface of the igniter 65. A gap between the upper end surface of the pedestal 640 and the lower end surface of the igniter 65 is formed by a protrusion 67.
[0058]
On the other hand, the remainder of the epoxy resin that has flowed into the inner peripheral side of the secondary spool 4 penetrates into the gap between the inner peripheral surface of the secondary spool 4 and the outer peripheral surface of the central core portion 5. FIG. 4 shows an enlarged view near the core support rib. As shown in the figure, the lower end surface of the heat shrinkable tube 52 is lifted by the core support rib 43. For this reason, a gap 93 is defined between the bottom wall upper surface 44 of the secondary spool 4 and the lower end surface 520 of the heat shrinkable tube 52. FIG. 5 is a cross-sectional view taken along the line II of FIG. As shown in the figure, the core support rib 43 bites into the heat shrinkable tube 52. However, the height of the core support rib 43 is set in consideration of the amount of biting. For this reason, the gap width L of the gap 93 is set to be relatively wide as 0.8 mm.
[0059]
As shown by the arrow in FIG. 4, the epoxy resin penetrates through the wide gap 93 and into the gap between the inner peripheral surface of the secondary spool 4 and the outer peripheral surface of the central core portion 5. For this reason, the void interposed between the inner peripheral surface of the secondary spool 4 and the outer peripheral surface of the central core portion 5 is pushed upward by the epoxy resin. Then, the void moves to the outer peripheral side of the secondary spool 4 from the gap between the outer peripheral surface of the alignment rib 63 and the upper peripheral inner surface of the secondary spool 4 shown in FIG. Then, the void rises on the outer peripheral side of the secondary spool 4 and moves to the outside of the ignition coil.
[0060]
Next, the effect of the ignition coil of this embodiment will be described. The ignition coil 1 of this embodiment includes a void removal passage 9. For this reason, the void 10 existing in the central core portion 5 can be removed relatively easily. Further, the ignition coil 1 of the present embodiment includes a connection void removal passage 91. For this reason, the void 10 staying in the inner circumferential side gap of the alignment rib 63 can be quickly removed. Further, the connection void removal passage 91 follows a path separated from the terminal 642 which is a member having a lower potential than the composite central core 54. For this reason, there is little possibility that the dielectric breakdown by peeling will occur. Further, the ignition coil of the present embodiment includes an auxiliary void removal passage 90. Also in this respect, the void 10 can be quickly removed. Further, a gap 93 having a width L = 0.8 mm is defined between the bottom wall upper surface 44 of the secondary spool 4 and the lower end surface 520 of the heat shrinkable tube 52. For this reason, there is little possibility that voids remain in the gap between the inner peripheral surface of the secondary spool 4 and the outer peripheral surface of the central core portion 5. Further, according to the present embodiment, the pedestal portion 640 is formed of two members, that is, a substrate 643 and a press-fit plate 644. The press-fitting plate 644 is provided with the alignment rib 63 and the connection void removal passage 91. For this reason, compared with the case where the base part 640 is formed with a single member, the connection void removal passage 91 can be arranged easily.
[0061]
(2) Second embodiment
The difference between this embodiment and the first embodiment is that the pedestal is formed of a single member, the connection void removal passage is formed by thinning the alignment rib, and heat shrinkage The longitudinal elastic modulus of the tube is set to 1250 MPa. Therefore, only the differences will be described here.
[0062]
  FIG. 6 shows a top view of the ignition coil of the present embodiment. FIG. 7 is a cross-sectional view taken along the line II-II in FIG. Note that the igniter is omitted. Further, parts corresponding to those in FIG. 3 are denoted by the same symbols. As shown in these drawings, the pedestal portion 640 is formed of a single member. An auxiliary void removal passage 91 extends in an L shape on the lower end surface 62 of the pedestal portion 640 and the inner peripheral surface of the alignment rib 63.LinkingTwo void removal passages 91 are arranged 90 ° apart from each other in the circumferential direction.
[0063]
FIG. 8 shows a cross-sectional view of the core support rib of the ignition coil according to the present embodiment. In addition, about the site | part corresponding to FIG. 5, it shows with the same symbol. The longitudinal elastic modulus of the heat-shrinkable tube 52 is relatively large at 1250 MPa. For this reason, as shown in the drawing, the core support rib 43 does not bite into the heat shrinkable tube 52. Therefore, the gap width L of the gap 93 is as wide as 1.0 mm.
[0064]
  According to this embodiment,LinkingTwo void removal passages 91 are arranged. For this reason, a void can be extracted from the center core part 5 more rapidly. Also,LinkingThe void removal passage 91 extends in an L shape on the lower end surface 62 of the pedestal portion 640 and the inner peripheral surface of the alignment rib 63. For this reason, simultaneously with the molding of the pedestal portion 640 and the alignment rib 63,LinkingA void removal passage 91 can be formed. Also,LinkingThere is no risk of undercut when the void passage 91 is formed. Further, according to the present embodiment, the longitudinal elastic modulus of the heat shrinkable tube 52 is set to 1250 MPa. For this reason, the biting into the heat shrinkable tube 52 of the core support rib 43 is suppressed.
[0067]
  (3)Other
  The embodiments of the ignition coil of the present invention have been described above. However, the embodiment is not particularly limited to the above form. Various modifications and improvements that can be made by those skilled in the art are also possible.
[0068]
For example, in the first embodiment, the upper elastic member 50 a is provided at the upper end of the composite central core 54. However, the upper end of the central core may be directly covered with an elastic tube without using an upper elastic member, and a hole may be provided in the upper end of the elastic tube.
[0069]
In the first embodiment, the alignment rib 63 is provided on the connector 64 for alignment of the central core portion 5. However, the elastic tube may be in contact with the inner surface of the spool for alignment without providing alignment ribs.
[0070]
In the first embodiment, the lower elastic member 50 b is disposed at the lower end of the composite central core 54. However, the lower end of the central core may be directly covered with the elastic tube without providing the lower elastic member, and the hole may be provided at the lower end of the elastic tube.
[0071]
In the first embodiment, the connector 64 is a member separate from the igniter 65, and the connecting void removal passage 91 is disposed in the connector 64. However, a connector may not be used, and a connecting void removal passage may be provided in the igniter 65 itself.
[0072]
In the above embodiment, the upper elastic member 50a is disposed at the upper end of the composite central core 54, and the lower elastic member 50b is disposed at the lower end. However, permanent magnets may be arranged at the upper and lower ends of the composite central core 54, and the upper elastic member 50a and the lower elastic member 50b may be arranged at the upper and lower ends of these permanent magnets. Moreover, in the said embodiment, although the silicon steel plate 540 was used as a magnetic member, you may use the wire rod made from a cement, for example. The shapes of the void removal passage 9, the auxiliary void removal passage 90, and the connection void removal passage 91 are not particularly limited. Any shape such as a hole shape and a slit shape can be used. Further, the number of void removal passages 9, auxiliary void removal passages 90, and connection void removal passages 91 is not particularly limited. Moreover, in the said embodiment, although the heat-shrinkable tube 52 was arrange | positioned as an elastic tube, you may arrange | position a rubber tube as an elastic tube, for example.
[0073]
The above description shows a structure in which a void removal passage is provided in an ignition coil having a structure in which an elastic tube or the like at the upper part of the central core contacts the lower end of the connector. Even in an ignition coil having a structure in which a resin insulating material is adjacent to the upper end surface of the elastic tube without contacting the lower end of the connector, a problem caused by the same void occurs. A hole may be provided in the member to release the void through the resin insulating material.
[0074]
【The invention's effect】
According to the ignition coil of the present invention, it is possible to easily remove the void existing in the central core portion.
[Brief description of the drawings]
FIG. 1 is an axial sectional view of an ignition coil according to a first embodiment.
FIG. 2 is an enlarged view of the vicinity of the central core portion of the ignition coil according to the first embodiment.
FIG. 3 is a top view of the ignition coil according to the first embodiment.
FIG. 4 is an enlarged view of the vicinity of a core support rib of the ignition coil according to the first embodiment.
5 is a cross-sectional view taken along the line II of FIG.
FIG. 6 is a top view of an ignition coil according to a second embodiment.
7 is a cross-sectional view taken along the line II-II in FIG.
FIG. 8 is a cross-sectional view of a core support rib of an ignition coil according to a second embodiment.
FIG. 9It is an enlarged view near the center core part of the conventional ignition coil.
[Explanation of symbols]
  1: Ignition coil, 2: Housing, 20: Wide opening, 21: Notch window, 3: Primary spool, 30: Primary winding, 31: Outer core, 4: Secondary spool (inner spool), 40: Secondary winding, 41: Spool side engaging claw, 42: Lower end opening, 43: Core support rib, 44: Bottom wall upper surface, 5: Center core portion, 50a: Upper elastic member, 50b: Lower elastic member, 52: Heat-shrinkable tube (elastic tube), 520: lower end surface (lower end surface of central core portion), 54: composite central core, 540: silicon steel plate (magnetic member), 6: connector portion, 62: lower end surface, 63: alignment rib, 64: Connector, 640: Pedestal part, 641: Square tube part, 642: Terminal, 643: Board, 644: Press-in plate, 65: Igniter, 66: Connector side engaging claw, 67: Projection, 7: High-pressure tower part 70: Tower housing 71: High Terminal: 72: Spring, 73: Plug cap, 74: Boss portion, 75: Projection, 76: Opening, 8: Epoxy resin (resin insulating material), 9: Void removal passage, 90: Auxiliary void removal passage, 91: Connecting void passage, 93: gap, 10: void, L: gap width.

Claims (8)

A housing;
Center having a rod-shaped central core, an upper elastic member disposed above the central core, and an elastic tube covering the central core and the upper elastic member from the outer peripheral side, arranged at substantially the center in the housing. The core,
A cylindrical primary spool disposed on the outer peripheral side of the central core portion and wound with a primary winding in the housing;
A cylindrical secondary spool disposed on the outer peripheral side of the central core portion and wound with a secondary winding in the housing;
The housing is disposed above the central core portion, and is inserted from above between the central core portion of the primary spool and the secondary spool that is disposed on the inner peripheral side and the central core portion, and the housing. A connector part having an alignment rib for aligning the central core part in the inside,
A resin insulating material that is injected into the housing and cured to ensure insulation between the members;
An ignition coil comprising:
Upper elastic member has a void vent passage through the upper elastic member in the vertical direction, the void vent passage, the connecting voids vent passage formed between the said connector portion lower surface central core portion upper surface The connecting void passage is located above the central core and follows a path away from a member having a lower potential than the central core, and the connection void passage communicates with the upper portion of the connector. An ignition coil, which is provided only in a direction in which a low-potential member is separated from a core axis, and that the portion is located outside a central core outer peripheral surface and above a central core upper end surface . A housing;
Center having a rod-shaped central core, an upper elastic member disposed above the central core, and an elastic tube covering the central core and the upper elastic member from the outer peripheral side, arranged at substantially the center in the housing. The core,
A cylindrical primary spool disposed on the outer peripheral side of the central core portion and wound with a primary winding in the housing;
A cylindrical secondary spool disposed on the outer peripheral side of the central core portion and wound with a secondary winding in the housing;
The housing is disposed above the central core portion, and is inserted from above between the central core portion of the primary spool and the secondary spool that is disposed on the inner peripheral side and the central core portion, and the housing. A connector part having an alignment rib for aligning the central core part in the inside,
A resin insulating material that is injected into the housing and cured to ensure insulation between the members;
An ignition coil comprising:
Upper elastic member has a void vent passage through the upper elastic member in the vertical direction, the void vent passage, the connecting voids vent passage formed between the said connector portion lower surface central core portion upper surface The connecting void removal passage is located above the central core, follows a path away from a member having a lower potential than the central core, and communicates with the outer peripheral side of the inner peripheral spool. Ignition coil to play. The central core portion includes a lower elastic member below the central core,
The elastic tube covers the central core, the upper elastic member, and the lower elastic member from the outer peripheral side,
The ignition coil according to claim 1, wherein the lower elastic member has an auxiliary void removal passage that penetrates the lower elastic member in the vertical direction.   The ignition coil according to claim 1 or 2, wherein the central core is a composite central core formed by joining a plurality of magnetic members. The inner circumferential spool includes a core support rib that is erected from the upper surface of the bottom wall of the inner circumferential spool and supports the lower end surface of the central core portion.
The ignition coil according to claim 1 or 2, wherein a gap between the upper surface of the bottom wall and the lower end surface of the central core portion defined by the core support rib is set to 0.7 mm or more and 2.0 mm or less. The elastic tube forms a lower end surface of the central core portion,
The ignition coil according to claim 1 or 2, wherein a longitudinal elastic modulus of the elastic tube is set to 1000 MPa or more and 1500 MPa or less. A housing;
A central core portion disposed substantially in the center of the housing and having a rod-shaped central core and an elastic tube covering from the upper end and the outer periphery of the central core;
A tubular primary spool disposed on the outer peripheral side of the central core portion and wound with a primary winding in the housing;
A cylindrical secondary spool disposed on the outer peripheral side of the central core portion and wound with a secondary winding in the housing;
The housing is disposed above the central core portion, and is inserted from above between the central core portion of the primary spool and the secondary spool that is disposed on the inner peripheral side and the central core portion, and the housing. A connector part having an alignment rib for aligning the central core part in the inside,
A resin insulating material that is injected into the housing and cured to ensure insulation between the members;
An ignition coil comprising:
Elastic tube has a void vent passage through the upper end of the elastic tube in the vertical direction, the void vent passage, the connecting voids vent passage formed between the said connector portion lower surface central core portion upper surface The connecting void passage is located above the central core and follows a path away from a member having a lower potential than the central core, and the connection void passage communicates with the upper portion of the connector. An ignition coil, which is provided only in a direction in which a low-potential member is separated from a core axis, and that the portion is located outside a central core outer peripheral surface and above a central core upper end surface . A housing;
A central core portion disposed substantially in the center of the housing and having a rod-shaped central core and an elastic tube covering from the upper end and the outer periphery of the central core;
A tubular primary spool disposed on the outer peripheral side of the central core portion and wound with a primary winding in the housing;
A cylindrical secondary spool disposed on the outer peripheral side of the central core portion and wound with a secondary winding in the housing;
The housing is disposed above the central core portion, and is inserted from above between the central core portion of the primary spool and the secondary spool that is disposed on the inner peripheral side and the central core portion, and the housing. A connector part having an alignment rib for aligning the central core part in the inside,
A resin insulating material that is injected into the housing and cured to ensure insulation between the members;
An ignition coil comprising:
Elastic tube has a void vent passage through the upper end of the elastic tube in the vertical direction, the void vent passage, the connecting voids vent passage formed between the said connector portion lower surface central core portion upper surface The connecting void removal passage is located above the central core, follows a path away from a member having a lower potential than the central core, and communicates with the outer peripheral side of the inner peripheral spool. Ignition coil to play.

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