JP2015095519A - Ignition coil for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition coil for internal combustion engine capable of preventing water from reaching the upper end of a blowhole at once, even when the water enters into a cover, and capable of discharging the water already entered into the cover, when the air in a plug hole is warmed by operation of an internal combustion engine and the volume is enlarged, and a positive pressure state is brought about.SOLUTION: Guide walls 68, 70 formed in the oblique direction for a ventilating section 56 are arranged in a cover 50, and the guide walls 68, 70 are formed so that the tip "a" is located on the opening 54 side of the cover 50 for the terminal. The guide wall 68 formed at a position close to the air chamber side vent hole connects the terminal with the ventilating section 56, and the guide wall 70 formed at a position close to the opening 54 of the cover 50 connects the terminal with the wall of the air chamber.

Description

  The present invention relates to an ignition coil for supplying a high voltage to an ignition plug provided in an internal combustion engine, and more particularly to an ignition coil for an internal combustion engine having a function of waterproofing a plug hole.

  Conventionally, an ignition coil for an internal combustion engine is plugged with a protector provided in a case of the ignition coil in order to securely connect with an ignition plug provided in a plug hole when mounted on the upper part of the engine. The top of the hole is sealed. In such an ignition coil, the internal pressure in the plug hole changes due to the temperature change of the engine, and when the ignition coil gets wet, the air in the plug hole is cooled and the volume is contracted, resulting in a negative pressure state. May penetrate. In order to solve this problem, it is known to form a water retention chamber in the ignition coil. For example, JP 2012-186299 A (hereinafter “Patent Document 1”) has been proposed.

  FIG. 7 is a cross-sectional view showing the configuration of an ignition coil for an internal combustion engine disclosed in Patent Document 1. In the ignition coil for an internal combustion engine of Patent Document 1, an air chamber portion 52 and a ventilation portion 56 are integrally formed on the left side of the coil case 20 in the illustrated left direction. Further, the air chamber portion 52 and the ventilation portion 56 communicate with each other at their upper portions. Further, the air chamber portion 52 has a “lower surface” that is a lower surface in which a cup is turned upside down.

  Further, by keeping the volume of the air chamber portion 52 larger than the volume shrinkage due to the temperature change in the plug hole 210, even if the water level in the air chamber portion 52 rises, continuous air flow in the plug hole 210 is achieved. Since it does not go up to the entrance of the part 56 (upper part of the ventilation part 56), water does not enter the plug hole 210. Thus, the volume of the air chamber 52 is set to 4 cc, for example. On the other hand, the volume of the plug hole 210 is about 40 cc, and the volume shrinkage due to the temperature change in the plug hole 90 in this case is about 2 cc. Therefore, the volume of the air chamber 52 is larger than the volume shrinkage (2 cc). It is getting bigger.

  In addition, an opening 220 is provided above the air chamber portion 52 and the ventilation portion 56. The sectional area of the opening 220 is smaller than the sectional area of the air chamber 52. At the upper part of the air chamber part 52, a ventilation part inlet 230 comprising a small opening communicating with the opening 220 is formed. The opening 220 is sealed with a seal member 240. As a result, the air chamber portion 52 and the ventilation portion 56 communicate with each other, and the ventilation portion 56 communicates with the outside air via the air chamber portion 52. It is described that the seal member 240 is fixed by press-fitting, adhesion, or welding.

  However, when water enters the air chamber part, there is a possibility that the water may reach the vent part entrance at once. In order to solve this problem, JP 2012-186411 A (hereinafter “Patent Document 2”) has been proposed as another example.

  The perspective view which shows the case part before attaching a cover concerning the ignition coil of patent document 2, and a cover is shown in FIG. In the ignition coil for an internal combustion engine of Patent Document 2, the column portion forming side wall portion 320 provided with the column portion 56 is located on the inner peripheral side with respect to the outer peripheral position of the seal rubber 40, and the column portion 56 is formed with the column portion. It is formed upward from a base portion 310 formed on the outer peripheral side of the side wall portion 320 and at an upper position with respect to the seal rubber 40. Further, the column part 56 is formed as a substantially semicircular cylindrical part as a part protruding toward the radial direction of the ignition coil 100 on the outer side surface 330 of the side wall part 22 of the case part 20. Further, the pillar portion forming side wall portion 320 is formed as a planar side wall portion in which a part of the circumferential direction located above the annular seal rubber 40 is recessed inward from the outer peripheral contour of the seal rubber 40. Yes.

  In addition, the base portion 310 is formed as a portion located on the inner peripheral side of the outer peripheral contour of the seal rubber 40 and on the outer peripheral side of the columnar portion forming side wall portion 320. Furthermore, the base portion 310 is provided with a protruding portion 340 that protrudes laterally with the plate surface directed in the vertical direction.

  Further, the cover 50 is attached to the notch 360 in the case portion 20 with the lower end forming the opening portion disposed around the protrusion 340. Further, the notch 360 is provided in the side wall portion 22 of the case portion 20 at both side positions with respect to the column portion 56 by being cut out in parallel downward from the side wall upper end portion 370, and the notch portion 360 is formed as a slit that is long in the vertical direction. The side walls 22 are formed in parallel to each other.

  In addition, on the columnar portion forming side wall portion 320, case wall portions 380 that are connected to the side wall portion 22 and the protruding portion 340 are erected in the vertical direction at both the left and right positions with respect to the column portion 56. Further, on the upper part of the inner side surface of the cover 50, cover wall portions 390 are arranged in the vertical direction so that the cover wall portions 390 are respectively arranged at the left and right side positions with respect to the column portion 56. It is described that each cover wall portion 390 is disposed between the column portion 56 and the case wall portion 380.

JP 2012-186299 A JP 2012-186411 A

  However, the above-described conventional ignition coil for an internal combustion engine has the following problems. That is, in Patent Document 2, even when water enters the cover, the water is respired by the case wall portion erected on the side wall portion and the cover wall portion erected on the upper portion of the inner side surface of the cover. A case wall that stands up upward from the protrusion when it becomes difficult to reach the upper end of the mouth, but when the internal combustion engine is operated and the air in the plug hole is warmed and the volume increases. This causes a problem that the water that has already entered the cover cannot be discharged by the portion.

  The present invention has been made in view of the above problems, and prevents water from reaching the upper end of the breathing port at a stretch even when water enters the cover, and warms the air in the plug hole by the operation of the internal combustion engine. It is an object of the present invention to provide an ignition coil for an internal combustion engine that can discharge water that has already entered the cover when a positive pressure state in which the volume is increased.

  In order to solve the above problems, the present invention is configured as follows. That is, the invention of claim 1 includes a coil portion comprising a primary coil, a secondary coil, and an iron core, a case for housing the coil portion, and a case for sealing the plug hole opening. In the ignition coil for an internal combustion engine provided with a protector to be mounted, a cover that forms an air chamber portion having an opening on the plug hole side is mounted on the side surface of the case, and the cover includes the plug A ventilation part having a ventilation hole connecting the inside of the hole and the inside of the air chamber part is formed, and at least one guide wall arranged obliquely with respect to the ventilation part is formed in the air chamber part. An ignition coil for an internal combustion engine.

  In the above configuration, the guide wall may be formed at a position where the distal end portion is closer to the opening than the end portion, and the guide wall includes the air chamber portion and / or the ventilation portion. You may connect. Alternatively, the guide wall may be formed on the case and / or the cover. Further, the guide wall near the opening connects the end portion to the air chamber portion side, and the guide wall close to the vent connects the end portion to the vent portion side. May be.

  As described above, a cover that forms an air chamber portion having an opening on the plug hole side is attached to the side surface of the case, and a ventilation portion having a vent hole that connects the inside of the plug hole and the air chamber portion is formed on the cover. In the air chamber portion, at least one guide wall arranged obliquely with respect to the ventilation portion is formed, so that even when water enters the cover, the water reaches the upper end portion of the ventilation port at once. In addition, the ignition coil for the internal combustion engine that can discharge the water that has already entered the cover when the air in the plug hole is warmed by the operation of the internal combustion engine to reach a positive pressure state in which the volume expands can be realized.

  In addition, the guide wall is formed at a position where the tip end portion is closer to the opening portion than the terminal end portion, so that the water that has once entered the cover can be discharged. Furthermore, since the guide wall is connected to the air chamber part and / or the ventilation part at the end part, the water entering the cover is only from the tip part, so that the water reaches the upper end part of the vent hole. Can be prevented.

  Further, by forming the guide wall in the case and / or the cover, it is possible to provide an ignition coil that does not require a change in the number of parts and the manufacturing process as compared with the conventional ignition coil. Furthermore, the guide wall on the side close to the opening is connected to the end portion on the air chamber portion side, and the guide wall on the side close to the vent is connected to the end portion on the vent portion side so that the guide wall is in the left-right direction. Therefore, it is possible to make it difficult for water to reach the upper end of the vent.

1 is a perspective view showing an ignition coil for an internal combustion engine according to a first embodiment of the present invention. A top view of the ignition coil of FIG. 1 viewed from the direction of arrow a is shown in (a), and a bottom view of the ignition coil viewed from the direction of arrow b is shown in (b). It is a perspective view which shows the assembly of the ignition coil made into Example 1. FIG. FIG. 4 shows an enlarged view of the ignition coil and cover of FIG. 3. The side view of the ignition coil of Example 1 is shown. It is the figure which showed the stroke | process which discharges | emits the water which penetrate | invaded in the air chamber part of the ignition coil of Example 1. FIG. 2 is a cross-sectional view showing a configuration of an ignition coil for an internal combustion engine of Patent Document 1. FIG. It is a perspective view which shows the case part before attaching a cover concerning the ignition coil of patent document 2, and a cover.

  An example showing the embodiment of the present invention will be described below with reference to FIGS.

  FIG. 1 is a perspective view showing an ignition coil for an internal combustion engine according to a first embodiment of the present invention, FIG. 1A is a top view of the ignition coil of FIG. 1 viewed from the direction of arrow a, and FIG. FIG. 2 is a bottom view of FIG. 2, FIG. 3 is a perspective view showing the assembly of the ignition coil, FIG. 4 is an enlarged view of the ignition coil and cover of FIG. 3, and FIG. FIG. 6 is a diagram showing a process of discharging water that has entered the air chamber portion of the ignition coil into FIG.

  1 to 5, an ignition coil 100 for an internal combustion engine includes an iron core having a closed magnetic circuit structure in which a central iron core and an outer iron core formed from a silicon steel plate are combined, and a primary arranged on the outer circumference of the iron core. It is comprised by the coil part 10 which consists of a coil and the secondary coil arrange | positioned on the outer periphery of the said primary coil. In addition, the coil portion 10 is housed in a case 20 that is formed from an insulating resin and has an upper surface in the vertical direction, and is filled with a thermosetting resin 80 to achieve physical fixation and electrical insulation. . Further, a connector 20a for supplying a power supply voltage and an ignition signal from an externally provided battery or ECU (engine control unit) to the coil unit 10 is formed on the side surface 22 of the case 20.

  Further, the ignition coil 100 is formed with a flange 20b for fixing to the engine head in the case 20, and the voltage from the battery is boosted by the coil portion 10 on the bottom surface of the case 20 to the ignition plug. A high-pressure tower 20c for supplying is formed. Further, the high-pressure tower 20c is provided with a protector 40 that securely connects the ignition coil 100 and the ignition plug and seals the opening to prevent water from entering the plug hole in which the ignition plug is provided. ing.

  Further, the case side surface 22 is provided with a cover 50 in which an air chamber portion 52 having an opening 54 on the protector 40 side is formed, and the cover 50 has a vent hole connecting the air chamber portion 52 and the plug hole. A ventilation portion 56 having 58 is formed. Further, the vent 56 is formed in a direction perpendicular to the opening 54 of the cover 50, and the air chamber side vent 60a formed in the air chamber 52 of the vent 58 includes the cover 50. It arrange | positions so that it may adjoin to the surface facing the opening part 54 of this.

  The case 20 has a passage formed by a cover side vent 28 and a protector side vent 34 connecting the vent 58 and the plug hole, and the cover side vent 28 is connected to the vent 60. It is connected to the case side vent 60b. Further, the protector 40 is formed with a passage formed by a case side vent hole 46a provided in the protector inner surface 42 and a plug hole side vent hole 46b provided in the protector outer surface 44. The case side vent hole 46a is formed in the case 20. By connecting to the protector side vent 34, the air chamber side vent 60a to the plug hole side vent 46b are configured as a direct passage.

  The cover 50 is provided with guide walls 68 and 70 formed in an oblique direction with respect to the ventilation portion 56, and the guide wall 68 formed at a position near the air chamber side ventilation hole 60a The portion 72b is connected to the ventilation portion 56, and a distal end portion 72a is formed on the opening portion 54 side of the cover 50 with respect to the end portion 72b. Further, the guide wall 70 formed at a position near the opening 54 of the cover 50 connects the end portion 74b to the wall of the air chamber portion 52, and a tip end portion 74a with respect to the end portion 74b. The cover 50 is formed on the opening 54 side.

  Further, the cover 50 and the case 20 are connected by fitting an air chamber side rib 62 formed in the cover 50 and an air chamber side rib insertion hole 24 formed in the side surface 22 of the case 20. ing. Similarly, the ventilation part 56 and the case 20 are formed by fitting a ventilation part side rib 64 formed in the ventilation part 56 and a ventilation part side rib insertion hole 26 formed in the side surface 22 of the case. Connected. Further, the cover 50 has a concave portion 66a at the connection portion with the case 20, and the case 20 has a convex portion 30a at the connection portion with the cover 50 to form a labyrinth mechanism. Similarly, the ventilation portion 56 has a concave portion 66b at the connection portion with the case 20, and the case 20 has a protrusion portion 30b at the connection portion with the ventilation portion 56, thereby forming a labyrinth mechanism.

  Returning to FIG. 2A, when the air chamber side rib 62 and the ventilation portion side rib 64 are fitted into the air chamber side rib insertion hole 24 and the vent hole side rib insertion hole 26, respectively. The mold resin filled in the case 20 is formed such that the front end portion 62a of the air chamber side rib 62 and the front end portion 64a of the ventilation portion side rib 64 reach the inner wall 32 of the case 20. Fixed by 80.

  Returning to FIG. 3, the ignition coil 100 is assembled in a state in which the coil portion 10 is accommodated in the case 20, and the arrow X, Y, and Z directions of the case 20 and the arrows X, Y, and Z directions of the cover 50. Are connected in the direction of arrow 1. Further, the connection between the case 20 and the cover 50 is performed by pressing with a jig so that the concave portion 66a of the cover 50 and the convex portion 30a of the case 20 are securely connected and the air chamber side rib. The distal end portion 62a of the 62 and the distal end portion 64a of the ventilation portion side rib 64 reliably reach the inner wall 32 of the case 20. Further, the case 20 and the protector 40 are connected in the direction of the arrow 2, and the high-pressure tower 20 c of the case 20 is fixed by being fitted to the inner surface 44 of the protector 40.

  In FIG. 6, when the internal combustion engine is submerged, the temperature of the internal combustion engine itself is lowered, and the air in the plug hole provided with the spark plug is also cooled. At this time, since the opening of the plug hole is sealed by the protector 40, the air in the plug hole is in a negative pressure state. Here, the negative pressure state is eliminated by introducing external air from the passage from the air chamber side vent 60a to the plug hole side vent 46b. Further, the case 20 is provided with the cover 50 having the air chamber portion 52, so that the air is kept in the air chamber portion 52 even when the ignition coil 100 is submerged. That is, as shown in FIG. 6A, when the air in the plug hole is in a negative pressure state, the air in the air chamber portion 52 is introduced through the vent 58 and water W enters the plug hole. The negative pressure state is eliminated without intruding.

  Further, when the internal combustion engine is removed from the flooded state, the temperature of the internal combustion engine rises and the air in the plug hole is warmed. At this time, the air in the plug hole is in a positive pressure state, and the positive pressure state is canceled by releasing the air in the plug hole from the passage from the air chamber side vent 60a to the plug hole side vent 46b. ing. That is, the air in the plug hole expands from the state where the internal combustion engine shown in FIG. 6A is flooded, and the water W in the air chamber portion 52 shown in FIG. 6B decreases. Finally, the water W does not remain in the air chamber 52 as shown in FIG. Incidentally, even during normal operation when the internal combustion engine is not flooded, the temperature of the internal combustion engine rises and the air in the plug hole expands, so that from the air chamber side vent 60a to the plug hole side vent 46b. The air in the plug hole is discharged from the passage.

  With the above-described configuration, the cover 50 is provided with the guide walls 68 and 70 formed in an oblique direction with respect to the ventilation portion 56, and the guide walls 68 and 70 are arranged at the tip end with respect to the end portions 72b and 74b. When the portions 72a and 74a are formed on the opening 54 side of the cover 50, when the ignition coil 100 is in a negative pressure state in which the air in the plug hole is cooled by water and the volume contracts. The water that has entered the air chamber 52 is unlikely to reach the upper end of the vent 58 at a stretch, and the ignition coil 100 is removed from the wet state, and the air in the plug hole is warmed by the operation of the internal combustion engine. All of the water that has already entered the air chamber 52 when the volume reaches a positive pressure state can be discharged.

  Further, the guide wall 68 formed at a position near the air chamber side vent 60a is formed at a position near the opening 54 of the cover 50 by connecting the end 72b to the vent 56. Further, the guide wall 70 connects the end portion 74b to the wall of the air chamber portion 52, so that the guide walls 68 and 70 overlap in the left-right direction, so that the water further reaches the air chamber side vent 60a. Can be difficult.

  As a modification of the first embodiment, the coil unit 10, the connector 20a, the flange 20b, and the high-voltage tower 20c are not limited to the configuration of the first embodiment and may be changed as appropriate according to the design circumstances. Good. The shape of the guide walls 68 and 70 may be arbitrarily changed according to design circumstances, and the number of the guide walls 68 and 70 formed in the cover 50 may be arbitrarily changed according to design circumstances. Also good. Furthermore, the guide walls 68 and 70 may be changed to an arbitrary angle depending on design circumstances with respect to the ventilation portion 56, but the angle of the guide portions 68 and 70 with respect to the ventilation portion 56 may be changed. If it is too small, it will not be possible to drain all the water that has already entered the air chamber 52 when the plug hole is in a positive pressure state, so all the water that has already entered the air chamber 52 will be discharged. It is desirable to set the angle within a range that can be performed.

  Further, the guide walls 68 and 70 are formed on the cover 50, but may be formed on the case 20, or the guide wall 68 near the air chamber side vent 60a by combining them may be formed on the case 20. The guide wall 70 formed near the opening 54 of the cover 50 may be formed on the cover 50. Further, the guide walls 68 and 70 may be formed as separate parts from the case 20 or the cover 50.

  Further, the guide wall 68 formed at a position near the air chamber side vent 60a is formed at a position near the opening 54 of the cover 50 by connecting the end 72b to the vent 56. Further, the guide wall 70 is configured such that the end portion 74b is connected to the wall of the air chamber portion 52 and the guide walls 68 and 70 are overlapped in the left-right direction. May be. Further, when the vent 56 is formed at the end of the air chamber 52 with respect to the radial direction of the vent 58, the effect of the present invention can be obtained by forming at least one guide wall 68, 70. Can be obtained.

10: Coil part
20: Case
22: Case side
24: Air chamber side rib insertion hole
26: Vent side rib insertion hole
28: Cover side vent
30a, 30b: Convex part
32: Case inner wall
34: Protector vent
40: Protector
50: Cover
52: Air chamber
54: Opening
56: Ventilation part
58: Vent
60: Air chamber side vent
62: Air chamber side rib
64: Ventilation side rib
66a, 66b: recess
68, 70: Information wall
80: Mold resin
100: Ignition coil

Claims (5)

A coil portion comprising a primary coil, a secondary coil, and an iron core;
A case for accommodating the coil portion;
In an ignition coil for an internal combustion engine provided with a protector attached to the case to seal the plug hole opening,
On the side surface of the case, a cover that forms an air chamber portion having an opening on the plug hole side is attached,
The cover has a ventilation part,
An ignition coil for an internal combustion engine, wherein at least one guide wall disposed in an oblique direction with respect to the ventilation portion is formed in the air chamber portion.   2. The ignition coil for an internal combustion engine according to claim 1, wherein the guide wall is formed such that a tip end portion is closer to the opening portion than a terminal end portion.   The ignition coil for an internal combustion engine according to claim 1 or 2, wherein the guide wall has the end portion connected to the air chamber portion and / or the ventilation portion.   The ignition coil for an internal combustion engine according to any one of claims 1 to 3, wherein the guide wall is formed on the case and / or the cover. The guide wall on the side close to the opening connects the end portion to the air chamber portion side,
5. The ignition coil for an internal combustion engine according to claim 1, wherein the guide wall closer to the vent hole connects the end portion to the vent portion side. 6.

Images