JP2000257542A - High tension joint connecting ignition coil of internal combustion engine with ignition plug - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an ignition plug from causing ignition failure due to backward flow of water by discharging air in a plug hole to the outside, and closing the plug hole normally. SOLUTION: Ventilation holes 29 (29a, 29b) communicating the inside of a plug hole with external air are opened and provided in a seal collar of an upper socket 22 provided with a hollow cylindrical part 23 which plunges into inner periphery of an upper end part of the plug hole 14 of an internal combustion engine in which an ignition plug 12 is attached to its bottom elastically and holds a high pressure cylindrical part 4 having a high pressure terminal 5 of an ignition coil 10 on inner periphery elastically and the seal collar 25 which overhangs from around the hollow cylindrical part 23 and comes into contact with an upper end opening of the plug hole 14 around the upper end opening elastically to seal the upper end opening of the plug hole 14 integrally. A check valve 30 which is closed normally, but is opened due to increase of internal pressure when internal pressure in the plug hole 14 increases to discharge air in the plug hole to the outside is provided in the ventilation hole 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage ignition plug fixed to an upper end opening of a plug hole provided at the bottom of a plug hole provided for each cylinder of an internal combustion engine such as an automobile engine. And a high-voltage joint that electrically connects the ignition coil and the ignition plug to generate spark discharge in the ignition plug.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 6-58237 discloses a high-pressure cylinder having a high-voltage terminal of an ignition coil, while elastically protruding into the inner periphery of the upper end of a plug hole of an internal combustion engine having a spark plug attached to the bottom. A hollow cylindrical portion elastically held on the inner periphery and a seal flange extending from around the hollow cylindrical portion and elastically contacting around the opening of the plug hole to seal the upper end opening of the plug hole are integrally formed. An upper socket provided on a lower socket that resiliently covers an upper portion having a top terminal of a spark plug attached to a bottom of the plug hole;
An insulating sheath comprising a relay tube connecting the upper socket and the lower socket; and a conductive member vertically supported in the insulating sheath and electrically connecting a high voltage terminal of the ignition coil and a top terminal of the ignition plug. A high-pressure joint for connecting an ignition coil of an internal combustion engine comprising a member to a spark plug is disclosed. This known high-pressure joint is extended from around the hollow cylindrical portion, and elastically contacts around the upper end opening of the plug hole to open the seal flange sealing the upper end opening of the plug hole by vertically penetrating the ventilation hole. When the internal pressure of the air in the plug hole rises, the excess air in the plug hole is discharged to the outside through the vent hole.

[0003]

Since the upper end of the ventilation hole formed vertically in the seal flange is always open,
When water enters the engine room and the water level rises above the upper end of the vent, the water reversely enters the vent from the upper end and penetrates into the plug hole, thereby causing ignition failure of the spark plug, There is a possibility that the performance of the engine is reduced.

[0004]

SUMMARY OF THE INVENTION The present invention has been developed to solve the above-mentioned problems, and resiliently projects into the inner periphery of the upper end of a plug hole of an internal combustion engine having a spark plug attached to the bottom. At the same time, a hollow cylindrical portion elastically holding a high-pressure cylindrical portion having a high-voltage terminal of an ignition coil on an inner periphery thereof, and protruding from around the hollow cylindrical portion and elastically contacting around an upper end opening of the plug hole. An insulating exterior material comprising: an upper socket integrally having a seal flange for sealing an upper end opening of the plug hole; and a lower socket elastically covering an upper portion having a top terminal of a spark plug attached to a bottom of the plug hole. And a conductive member vertically supported in the insulating sheathing material and electrically connecting the high voltage terminal of the ignition coil to the top terminal of the ignition plug. In a high-pressure joint for connecting an ignition coil of an internal combustion engine with an ignition plug having an opening communicating the inside of the hole to the outside air to the ignition plug, the opening is always closed, and when the internal pressure in the plug hole increases, the internal pressure increases. And a check valve that opens to release the air in the plug hole to the outside is provided.

[0005] The check valve includes a lower small-diameter hole provided in the vent hole, a large-diameter hole above the lower-diameter hole, and a valve seat formed at a boundary between the small-diameter hole and the large-diameter hole. A valve body having a diameter larger than the small diameter hole and smaller than the large diameter hole, received on the valve seat by its own weight, and separated upward from the valve seat due to an increase in internal pressure in the plug hole. Can be configured.
Also, the check valve may be constituted by an elastic piece closing the upper end of the ventilation hole, and a cut formed in the elastic piece and always closed, and opened by an increase in internal pressure in the plug hole.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Is an ignition coil, 1 is a primary coil, 2 is a secondary coil concentrically fitted with the primary coil, 3 is a bottomed insulating case formed of a synthetic resin or the like, and the case has a primary bottom. It has an opening closed at one end of the bobbin of the coil. A high-pressure cylinder 4 protrudes from one side wall of the insulating case, and a high-voltage terminal 5 is mounted in the cylinder. A primary terminal seat 6 is provided on the other side of the side wall, and a primary terminal 7 is attached thereto. The primary coil and the secondary coil, which are fitted concentrically, stand on the bottom in the insulating case, close the bottom opening at one end of the bobbin of the inner primary coil, and close the winding of the secondary coil. The winding end is connected to the high voltage terminal, and the winding of the primary coil is connected to the primary terminal 7, respectively.
A thermosetting insulating resin, for example, an epoxy resin is filled in the insulating case by vacuum casting, and both the primary and secondary coils are placed in the insulating case by the solidified insulating resin layer 8, and a high voltage The terminals 5 are fixed, and the high voltage derived from the secondary coil is insulated. Then, the inner legs of a pair of iron cores 9 constituting a closed magnetic path such as a U-shape or a J-shape are inserted into the inner periphery of the bobbin of the primary coil from each end and fixed in a contact state by bonding or the like. The outer legs 9a, 9a of the two cores are directly butted outside the insulating case or butted via a permanent magnet and fixed by bonding, welding, or the like. Thus, the illustrated ignition coil 10 is assembled.

In a cylinder head 11 of an internal combustion engine, a plug hole 1 having a spark plug 12 attached to the bottom for each cylinder is provided.
4 is provided for each cylinder. In the illustrated ignition coil 10, the ends 9 ′, 9 ′ of the pair of iron cores 9, 9 protrude out of the insulating case, and are used to fix the ignition coil directly above the plug hole. In the cylinder head, support bases 15, 15 are provided on the left and right of the upper end opening of the plug hole.
There is standing. Accordingly, the high-pressure cylinder of the ignition coil is directed downward and shallowly projects into the center of the upper end of the plug hole, and the respective ends 9 ', 9' of the iron core are placed on the supports 15, 15, and from each end, the support The screws 16 and 16 are screwed in from above and tightened on the end of the iron core.
0 can be fixed directly above the plug hole. still,
Each end 9 ′ of the iron core is a connection between the outer leg and the inner leg of the iron core.

Reference numeral 20 denotes a high voltage generated at the high voltage terminal 5 via the secondary coil when the current flowing through the primary coil of the ignition coil is cut off, to the top terminal 13 of the ignition plug 12 mounted at the back of the plug hole. A hollow high-pressure joint, which elastically protrudes into the upper inner periphery of the plug hole 14 and elastically holds the high-pressure cylindrical portion 4 of the ignition coil on the inner periphery, and protrudes from around the hollow cylindrical portion. An upper socket 22 integrally provided with a seal flange 25 for elastically contacting the peripheral edge of the cylinder head around the upper end opening of the plug hole and sealing the upper end opening of the plug hole, and is attached to the bottom of the plug hole. An insulating sheathing material comprising a lower socket 26 elastically covering an upper portion having a top terminal 13 of a spark plug, and a relay tube 27 connecting the upper socket 22 and the lower socket 26. 1, is supported in the vertical direction during the external packaging material, a high voltage terminal 5 of the ignition coil is composed of a top terminal 13 of the spark plug a conductive member 28 that electrically connects, for example, a metal coil spring.

The upper socket 22 and the lower socket 26 are formed of synthetic rubber and synthetic resin having high elasticity, and the relay cylinder 27 is formed of ordinary synthetic resin. Then, the upper and lower ends of the relay tube are fitted into the inner periphery of the upper socket and the lower socket, then inserted into an annular groove provided concentrically outside the inner periphery, and fixed by bonding or the like, and the high-pressure joint is fixed. Assemble. When the plug hole is shallow, the relay cylinder may be omitted, and the upper socket and the lower socket may be integrally molded to form an insulating exterior material.

On the outer periphery of the hollow cylindrical portion 23 of the upper socket, a vertical groove is provided below and a hole communicating with the vertical groove is provided thereon, and the hollow cylindrical portion is elastically connected to the upper end of the plug hole from above. When the plug is inserted, a vertical gap 24 is formed between the vertical groove and the hole at the inner periphery of the upper end of the plug hole. The seal flange 25 is provided with a vertically extending ventilation hole 29 communicating with the gap 24. The ventilation hole 29 is always closed. When the internal pressure of the plug hole 14 increases, the plug hole 14 opens due to the increase of the internal pressure. A check valve 30 for discharging the air in the hall to the outside is provided.

Accordingly, the upper socket 22 of the high voltage joint 20 is fitted to the high voltage cylinder of the ignition coil, the upper end of the conductive member 28 is connected to the high voltage terminal 5, and the high voltage joint is attached to the ignition coil. When inserted from above, the lower socket is elastically placed over the upper part of the spark plug, and when the lower end of the conductive member 28 of the high-voltage joint is brought into contact with the top terminal 13 of the spark plug, the hollow cylindrical part 23 of the upper socket is inserted into the plug hole. Push into the inner circumference of the upper end,
In addition, when the seal flange 25 is brought into contact with the upper end opening of the plug hole to seal the upper end opening of the plug hole, the air in the plug hole is compressed to increase the internal pressure, and excess air flows from the gap 24 to the vent hole 29. It enters from below, pushes open the check valve 30 and discharges out above the seal flange 25. Also, when the air inside the plug hole thermally expands due to the operation of the internal combustion engine and the internal pressure increases, the air similarly flows from the gap 24 to the vent hole 29.
From below, pushes open the check valve 30 and escapes above the seal flange 25. Then, the ignition coil 10 is fixed on the supports 15 and 15 with screws.

When the internal pressure in the plug hole is not high, the check valve 30 is always closed, so that even if the internal combustion engine is immersed in water and the water level becomes higher than the upper end of the vent hole 29 of the seal flange 25, Water is blocked by the check valve 30 and does not enter the plug hole. Therefore, ignition failure of the ignition plug does not occur.

The check valve 30 of the embodiment shown in FIG.
9, a small-diameter hole 29a at a lower portion, a large-diameter hole 29b above the small-diameter hole 29, a valve seat 31 formed at a boundary between the small-diameter hole and the large-diameter hole, The portion 29a is larger than the portion 29a and smaller than the large-diameter hole portion 29b. The small-diameter hole portion 29a is received on the valve seat 31 by its own weight to close the small-diameter hole portion 29a. And a valve element 32 that opens the small-diameter hole. The valve body 32 may be spherical as shown, but may be a mushroom shape that is thinner than the small-diameter hole 29a and integrally has a downward center leg that projects shallowly from above into the small-diameter hole. In order to prevent the valve body 32 from escaping from the upper end of the large-diameter hole 29b, a cylindrical stopper 33 for preventing the valve body from escaping may be attached to the inner periphery of the upper end of the large-diameter hole. preferable.

When the internal pressure in the plug hole is increased by the check valve 30, the air separates the valve body 32 upward from the valve seat 31, and the air from the valve seat 31 to the outer periphery of the valve body 32 and the large diameter portion 29 of the vent hole.
B escapes from the upper end of the ventilation hole through the gap between the inner periphery of b and the outside (FIG. 1B). When the pressure in the plug hole becomes equal to the atmospheric pressure, the valve element 32 falls on the valve seat 31 to prevent the valve seat from above, thereby preventing water from entering the plug hole (FIG. 1A). ). Preferably, the upper end of the vent hole 29 is opened at the center of the hemispherical dome-shaped portion 22 'raised on the upper surface of the upper socket to prevent water from entering the vent hole as much as possible.

The check valve 30 of the embodiment shown in FIG.
An elastic piece 34 closing the upper end of the plug 9 and a cut 35 formed on the elastic piece and always closed and pushed open by air due to an increase in internal pressure in the plug hole. The elastic piece 34 may be formed integrally with the upper socket, or may be formed separately and fixed to the upper surface of the upper socket by bonding or the like so as to close the upper end of the ventilation hole. If the cut 35 is formed in a cross shape, it may open downward due to the weight of water. Therefore, as shown in the figure, it is preferable to form the cut 35 in a one-letter shape in the diameter direction of the vent hole.

When the internal pressure in the plug hole is increased by the check valve 30, the air pushes up the elastic piece 34, which opens the cut 35, and escapes through the open cut 35 (FIG. 2). (C)). When the pressure in the plug hole becomes equal to the atmospheric pressure, the elastic piece 34 is resiliently restored, whereby the cut is closed to prevent water from entering the plug hole (FIG. 2 (A)). Also in this embodiment, the elastic piece 34 at the upper end of the ventilation hole is formed in a hemispherical dome shape, and is raised from the upper surface of the upper socket to make it difficult for water to open the cut 35 from the outside, and to prevent water from entering the plug hole. Preferably, it is prevented.

As described above, the present invention has been described with reference to the illustrated embodiments, but the present invention is not limited to these embodiments. For example, as disclosed in Japanese Patent Application Laid-Open No. Hei 10-223463, an ignition coil includes an endless iron core such as an annular shape, and a central iron core having both ends connected to the endless core diametrically across the inside surrounded by the endless iron core. The closed magnetic circuit core consisting of and the closed magnetic circuit core are placed horizontally, and a high-pressure cylinder with a high-voltage terminal attached to the inner periphery protrudes downward from the bottom, and a thermosetting insulating resin is cast and filled inside. And a case in which the high-pressure cylinder is supported with the high-pressure cylindrical portion facing downward inside a recess of the rocker cover fixed and located on a plug hole of a cylinder head of the engine, and an upper socket of a high-pressure joint. The above-mentioned downward high-pressure cylinder portion is elastically held on the inner periphery, and a downward-direction annular cylinder portion projecting from around the annular bottom of the rocker cover communicating with the plug hole of the engine from above. A hollow cylindrical portion that comes into contact with the periphery, a seal flange that protrudes from around the hollow cylindrical portion, and that contacts the annular ridge protruding from around the annular bottom of the rocker cover from above to seal the annular bottom of the rocker cover; In any case, the design can be changed within a frame in accordance with the technical concept described in the claims of the present invention.

[0018]

As is apparent from the above, according to the present invention, the high-pressure joint is provided with a ventilation hole for communicating the inside of the plug hole with the outside air at the sealing flange for sealing the upper opening of the plug hole. When the high-pressure joint is inserted into the plug hole, a check valve is provided that always closes, opens when the internal pressure in the plug hole increases, and releases the air in the plug hole to the outside when the internal pressure increases. To
The check valve opens when the internal pressure increases due to the compression of the air in the plug hole or when the internal pressure increases due to the thermal expansion of the air in the plug hole due to the operation of the internal combustion engine. Can be released outside. And since the check valve is always closed, even if water tries to enter backward through the vent hole, it is blocked by the check valve. Therefore, it is possible to reliably prevent the possibility that water may enter the plug hole and cause the ignition plug to fail in ignition.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view illustrating an example of a use state in which a main part of an example of a high-pressure joint according to the present invention is enlarged.
2 is an enlarged sectional view showing a state in which the check valve is open.

FIG. 2A is a cross-sectional view showing an example of a use state in which main parts of another example of the high-pressure joint according to the present invention are enlarged, FIG. 2B is a plan view of the seal flange, and FIG. () Is an enlarged sectional view showing a state where the check valve is open.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ignition coil 11 Cylinder head 12 Ignition plug 13 Top terminal of ignition plug 14 Plug hole 20 High pressure joint 21 Insulation exterior material of high pressure joint 22 Upper socket of insulation exterior material 23 Hollow cylinder part of upper socket 24 Plug hole and hollow cylinder part 25 Seal flange of upper socket 26 Lower socket of insulating sheathing 28 Conductive member of high-pressure joint 29 Vent hole of seal flange 30 Check valve provided in vent hole

Claims (3)

[Claims] An internal combustion engine having a spark plug attached to the bottom thereof elastically protrudes into an inner periphery of an upper end portion of a plug hole,
A hollow cylindrical portion elastically holding a high-pressure cylindrical portion having a high-voltage terminal of an ignition coil on an inner periphery thereof, and extending from around the hollow cylindrical portion,
An upper socket integrally having a sealing flange for elastically contacting around an upper end opening of the plug hole and sealing the upper end opening of the plug hole; and a top terminal of a spark plug attached to a bottom of the plug hole. An insulating sheathing material having a lower socket elastically covering an upper part thereof; and a conductive member vertically supported in the insulating sheathing material and electrically connecting a high voltage terminal of the ignition coil and a top terminal of the ignition plug. A high-pressure joint for connecting an ignition coil of an internal combustion engine to an ignition plug, in which a ventilation hole for communicating the inside of the plug hole with the outside air is provided in the sealing flange of the upper socket, the ventilation hole is always closed, An internal combustion engine having a check valve that opens when the internal pressure in the plug hole increases and releases the air in the plug hole to the outside; High pressure joints for connecting the ignition coil to the spark plug. 2. The high pressure joint for connecting an ignition coil of an internal combustion engine to an ignition plug according to claim 1, wherein the check valve includes a lower small-diameter hole portion provided in the vent hole and a large-diameter hole portion above the lower hole portion. A diameter hole portion, a valve seat formed at a boundary between the small diameter hole portion and the large diameter hole portion, and a diameter larger than the small diameter hole portion, smaller than the large diameter hole portion, and self-weight on the valve seat. A high-pressure joint for connecting an ignition coil of the internal combustion engine to the ignition plug, the valve being separated from the valve seat by an increase in internal pressure in the plug hole. 3. The high pressure joint for connecting an ignition coil of an internal combustion engine to an ignition plug according to claim 1, wherein the check valve has an elastic piece for closing an upper end of the ventilation hole, and the check piece is always formed on the elastic piece. A high-pressure joint for connecting an ignition coil of an internal combustion engine to a spark plug, comprising a cut which is closed and opened by an increase in internal pressure in a plug hole.