JPH02221681A - Ignition coil mounting structure for internal combustion engine - Google Patents

Abstract

PURPOSE:To certainly prevent the entrance of lubricating oil into each coil mounting hole by interposing a seal member between opposite surfaces of the upper surface of a cylinder head and the lower surface of a rocker cover having coil mounting holes continuously formed in the respective inner parts. CONSTITUTION:A cylinder head 11 having a cam chamber 13 in its upper part has an ignition plug hole 17 communicated with a combustion chamber 16 in the lower part of its center part 15 and also a first coil mounting hole 18 continued thereto. A rocker cover 12 mounted on the upper surface of the cylinder head 11 has a second coil mounting hole 20 continued to the diameter part 18a of the first coil mounting hole 18 on its cylindrical part 19. In the above constitution, a ring seal member 35 having a nearly L-shaped cross sectional form is interposed between the continued part outer circumference of the first and second coil mounting holes 18, 20. Hence, the circumference of each coil mounting hole 18, 20 is sealed water-tightly, and the entrance of lubricating oil into each coil mounting holes 18, 20 is certainly prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an ignition coil for an internal combustion engine, and more particularly to a mounting structure for an ignition coil that is independently disposed in a cylinder head for each cylinder.

Prior Art A low-voltage electronic power distribution ignition system is known in which a relatively small ignition coil is arranged on the cylinder head for each cylinder and a strong voltage is applied to each spark plug to reduce loss of ignition power. (See Utility Model Application Publication No. 62-74173, etc.).

As shown in FIG. 7, a casing 2 is formed by integrally extending the cap of a spark plug l upward, and an ignition coil 3 is housed inside the casing 2. and,
The so-called D OHC type internal combustion engine is arranged so that the rocker cover 4 and the cylinder are inserted into the central cavity 7 of the throat 5, and the tip of the casing 2 is connected to the cylinder via the spark plug 1 through the spark plug hole in the center of the throat 5. The upper end is screwed and fixed to the center of the rocker cover 4 with a nut 6,
The whole is adapted to be mounted vertically on the cylinder head 5.

Problems to be Solved by the Invention However, in the conventional ignition device described above, the central cavity 7 in which the casing 2 is housed is separated from the cam chamber 9 in which the cam journals 8, 8 at the upper part of the cylinder head 5 and the cam bearings are housed. ，
Since it is in communication with cam journal 8, 8
The lubricating oil supplied to the cam chambers 9, 9 as shown by the arrows
It invades into the central cavity 7 from the inside. For this reason, the casing 2 is immersed in lubricating oil, and when the casing 2 is attached or detached, the lubricating oil not only adheres to the terminal members and impairs current conductivity, but also enters the inside of the casing 2 and damages each component. There is a risk of adverse effects.

Means for Solving the Problems The present invention was devised to solve the above-mentioned conventional problems, and includes a sealing member interposed around the coil mounting hole where the upper surface of the cylinder head and the lower surface of the rocker cover face each other. It is characterized by

Effects According to the present invention having the above configuration, the area around the coil mounting hole in the vicinity of the upper and lower opposed surfaces of the printer head and the rocker cover is sealed watertight by the sealing member, so that the lubricating oil supplied into the cam chamber etc. is not attached to the coil. Intrusion into the hole is reliably prevented.

Example Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

Figure 1 shows the mounting structure of the ignition coil according to the present invention.
-The case is shown when applied to an IC type V-type 6-cylinder internal combustion engine. That is, in the figure, 11 is an aluminum alloy cylinder head having a cam chamber 13 in the upper part, and 12 is a cylinder head whose lower part is placed and fixed to the rocker cover 14 on the upper surface of each cylinder Rad 11 with bolts (not shown). 11
and an ignition coil installed across the rocker cover 12. The cylinder head 11 is internally provided with intake and exhaust valves (not shown) facing each other at a predetermined included angle, and a combustion chamber 16 is located at the lower part of the central portion 15 between the intake and exhaust valves. A spark plug hole 17 communicating with the spark plug hole 17 is formed in an inclined manner, and a first coil mounting hole 18 is formed continuously in an inclined manner above the spark plug hole 17. As shown in FIG. 2, this first coil attachment hole 18 has a large diameter portion 18a on the upper side and a small diameter portion 18b on the lower side of the spark plug hole 17, and the center X of the large diameter portion 18H. is arranged slightly eccentrically to the right in the figure from the center Y of the small diameter portion 18b, and the large and small diameter portion 18a.

The step portion 18c of the step portion 18b has an arcuate surface and a small diameter portion 1
It is formed in a downward taper shape toward the 8b side.

As shown in FIGS. 1 and 3, the rocker cover 12 has a substantially arcuate upper wall 12a with an inner surface located substantially at the center of the upper wall 12a.
Three cylindrical parts I9 facing the central part 15...
are vertically installed in an inclined manner, and the cylindrical portion 19...
- A large-diameter second coil mounting hole 20 that is continuous with the large-diameter portion 18a of the first coil mounting hole 18 is bored. Further, the upper wall 12a is provided with a boss portion 21 having a bolt threading hole on the upper surface near the edge of the second coil attachment hole 20, and a ring-shaped boss portion 21 is provided around the edge of the second coil attachment hole 20. A rising locking portion 22 is integrally provided.

On the other hand, as shown in FIGS. 1 and 6, the ignition coil 14 includes a fill portion 24 housed inside a casing 23 made of synthetic resin, and a substantially cylindrical plug attached to the tip of the casing 23. The connecting portion 25, the mounting flange 26 provided on the side surface of the upper end 23a of the casing 23, and the upper end 23a of the casing 23.
An annular elastic engagement part 27 is provided on the lower outer periphery of the coil part 24 and is fitted onto the locking part 22 from above; and a power connector 28.

The casing 23 has an outer shape that is substantially the same as the inner surface of the first film attachment hole 18, which is formed into a cylindrical shape.
0, a large diameter cylindrical part 23b that is inserted into the large diameter part 18a, and a small diameter cylindrical part 23C that is inserted into the small diameter part 18b. It is eccentric by the same amount of eccentricity as the center of the portion 18b. The outer surface of the stepped portion 23d between the two cylindrical portions 23b and 23C is formed in a substantially arc shape and tapered shape so as to fit into the upper surface of the stepped portion 18c.

The coil portion 24 has an iron core 30 that is provided inside the large-diameter cylindrical portion 23b and is eccentric to the axis of the spark plug 29.A primary coil and a secondary coil are wound around the outer periphery of the iron core 30 in a cylindrical shape. It's being passed around.

Further, the plug connecting portion 25 is formed of a heat-resistant elastic material, and is attached to the tip of the small diameter cylinder portion 23C to connect the spark plug 2.
A terminal member 33 is disposed coaxially with the terminal member 9 and is biased by a coil spring 32.
It is adapted to come into pressure contact with a terminal portion 29a at the tip of the spark plug 29. Further, a flange 25a that comes into elastic contact with the inner peripheral surface of the small diameter portion 18b is integrally provided on the outer periphery of the upper end. Note that the terminal member 33 is arranged eccentrically with respect to the iron core 30.

Further, the mounting flange 26 is fixed to the boss portion 21 of the rocker cover 12 with bolts 34, as shown in FIG.

Further, the power supply connector 28 located on the substantially opposite side to the mounting flange 26 is formed toward the camshaft axial direction. That is, the connector at the end of the primary current supply cord (not shown) is inserted in the axial direction of the camshaft and connected.

Then, a cross section is formed between the upper surface of the central portion 15 of the cylinder head 11 and the lower surface of the cylindrical portion 19 of the rocker cover 12, that is, on the outer periphery of the connection point between each of the first coil mounting holes 18 and the second coil mounting holes 20. A letter-shaped annular seal member 35 is interposed in each case.

Each of the seal members 35 is made of heat-resistant synthetic rubber, and as shown in FIGS. 4 and 5, there are three elongated connecting portions 36 corresponding to the three coil mounting holes 18 and 20 in one bank. .36, and each comprises a horizontal base 35a and a side wall 35b rising from the outer peripheral edge of the base 35a. Further, the inner diameter of the base portion 35a is set to be the same as the inner diameter of each coil mounting hole 18.20, and the inner diameter of the side wall portion 35b is set to be the same as the inner diameter of each coil mounting hole 18.
The outer diameter of the cylinder part 9 and the distance between the grooves are set so that the whole part is aligned with the lower end of the cylindrical part 19.

Additionally, annular seal portions 39.39 are provided at both ends of the connecting portion 36.36 to seal the edges of the bolt holes 38a, 38b of the mounting bolts for attaching the rocker cover 12 to the cylinder head 11. 39.3
9 also has a cross-sectional abbreviated shape, and is adapted to fit into a cylindrical boss portion 40 forming the bolt hole 38a of the rocker cover 12.

The operation of this embodiment will be explained below.

First, when installing each seal member 35, each seal member 35 is fitted into the cylindrical portion 19 of the rocker cover 12, and each seal portion 39 is also fitted into the cylindrical boss portion 40. Then, the rocker cover 12 is attached to the cylinder rad 11.
If the seal member 35 is placed in a predetermined position and tightened with bolts, the base 35a of the seal member 35 will be connected to the upper surface of the central portion 15 of the cylinder head 11 and the cylindrical portion 19 of the rocker cover 12.
- Pressure is applied between the lower surfaces to provide a watertight seal around the connecting portion of each coil mounting hole 18, 20. In addition, the seal portion 39
Of course, each bolt hole 38a, 38b is also sealed. Here, each seal member 35 and seal portion 39 are
Since they are connected by the connecting portions 36, 36, not only the attachment work to the rocker cover 1 is facilitated, but also its maintenance management is also facilitated.

Next, after screwing and fixing the ignition plug 29 into the ignition plug hole 17 in advance, in order to assemble the ignition coil 14 onto the cylinder rod 11, insert the ignition coil 14 from above the insertion hole 20 of the rocker cover 12 into the cylinder. When the ignition coil 14 is pushed into the coil attachment hole 18 of the henode 11, the casing 23 of the ignition coil 14 is inserted and moved while being guided along the inner surfaces of the large diameter portion 18a and the small diameter portion 18b, and the stepped portion 23d is inserted into the coil attachment hole 18. At the position where it hits the stepped portion 18c,
If you rotate it slightly left and right without pushing it, both will reach 18G.
, 23d are brought into contact with each other in a conforming manner. Therefore, further insertion of the ignition coil 14 is regulated, and the height positioning is done simultaneously.
Positioning in the rotational direction is performed by fitting the eccentric large and small diameter cylindrical portions 23b and 23C of the casing 23 to the large and small diameter portions 18a and 18b of the casing 23. And such ignition coil 1
4, when the insertion is completed, the flange 25 of the plug connection part 25
a elastically contacts the inner circumferential surface of the small diameter portion 18b, while the elastic body engaging portion 27 at the upper end of the casing 23 contacts the rocker cover 1.
The second locking part 22 is clamped, and then the mounting flange 26 is tightened and fixed to the boss part 21 with the bolt 34.

Therefore, not only is the ignition coil 14 firmly attached to the cylinder head 11 and the rocker cover 12, but also the height of the ignition coil 14 is determined as described above.
... can all be made uniform in height, thereby making it possible to equalize the pressure force between the terminal member 33 and the tip of the spark plug 29.

Furthermore, by positioning in the rotational direction, all the connectors 28 can be oriented uniformly in the camshaft axis direction. Furthermore, the step portion 23d and the step portion 1
Due to the axial regulation by the contact with 8c, the insertion depth and direction of insertion of the ignition coil 14 during assembly on the factory line can be easily controlled, and assembly work efficiency is improved.

Furthermore, since the mounting flange 26 is fixed to the boss portion 21 with the bolts 34, the ignition coil 14 is held in a well-balanced manner with respect to the cylinder rod 11 and the rocker cover 12. Therefore, transmission of vibrational force or stress to the coil portion 24 from the contact point between the cylinder rad 11 and the ignition coil 14 due to vibrations during engine operation is sufficiently prevented.

Further, approximately the center of the rocker cover 12 is located at the ignition coil 1.
4, it is connected to the cylinder head 2 via
In addition, due to the weight of the ignition filter 14, the rocker cover 1
2 vibration can be effectively suppressed. Note that this vibration suppressing effect makes it possible to maintain good sealing performance between the rocker cover 12 and the cylinder head 11.

Further, since the elastic body engaging portion 27 is fitted into the locking portion 22 and the flange 25a of the plug connecting portion 25 is in elastic contact with the small diameter portion 18b, the rad 1 is attached to the rocker cover 12 or the cylinder.
The vibration of the elastic body engaging portion 27 and the plug connecting portion 25
The terminal member 33 inside the ignition coil 14 is protected, and a sealing effect is obtained between the outside and the coil mounting hole. In particular, the inside of the small diameter portion 18b is sealed in two stages together with the seal member 35. Intrusion of lubricating oil can be more reliably prevented.

Furthermore, since the ignition coil 14 is arranged eccentrically with respect to the spark plug 29, it is possible to easily apply it not only to the DO[-1C type internal combustion engine but also to the ■ type internal combustion engine. That is, in a DOHC type internal combustion engine, the ignition coil 1 is located in the center between a pair of camshafts.
If you try to install this type of ignition filter 14, it will be difficult to install this type of ignition filter 14 because the included angle of the intake pulp and exhaust valve will be restricted. In addition, in the ■ type internal combustion engine, when the ignition coil 14 is installed in the center of the cylinder head 11,
Due to the left and right bank angles, the ignition coil 14 is located at a lower position, making maintenance etc. inconvenient. Therefore, as in the present invention, the above-mentioned problems are eliminated by making the ignition coil 14 eccentric, so that the present invention can be applied to various internal combustion engines.

Effects of the Invention As is clear from the above explanation, according to the present invention, in particular, the sealing member provides a watertight seal between the cam chamber, etc. and the coil mounting hole. Intrusion of lubricating oil into the coil mounting hole is reliably prevented.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment in which the ignition coil mounting structure of the present invention is applied to a DOHC type internal combustion engine, and Fig. 2 is an enlarged sectional view taken along line II in Fig. 1 showing the coil mounting hole of this embodiment. , FIG. 3 is a bottom view of the rocker cover used in this embodiment, and FIG. 4 is a plan view showing the sealing member of this embodiment.
5 is a sectional view taken along the line IV--IV in FIG. 4, FIG. 6 is a plan view of the ignition coil of this embodiment, and FIG. 7 is a sectional view showing a conventional ignition coil mounting structure. DESCRIPTION OF SYMBOLS 11... Cylinder head, 12... Rocker cover 14... Ignition coil, 18... First coil mounting hole,
20... Second coil mounting hole, 35... Seal member.

Claims (1)

[Claims] (1) In an ignition coil mounting structure comprising a cylinder head having a cam chamber in the upper part and a rocker cover placed and fixed on the upper surface of the cylinder head, coil mounting holes are continuously formed inside each cylinder head. An ignition coil mounting structure for an internal combustion engine, characterized in that a sealing member is interposed around the coil mounting hole where the upper surface and the lower surface of the rocker cover face each other.