JPS60209612A - Valve driving device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To contrive the weight saving and compactness of the device by a method wherein a main body part of an ignition plug is contained in a space formed of a cam shaft, a rocker shaft, a pair of intake valve rocker arms and a pair of intake valves, then the location of the ignition plug is arranged on a axis line of a cylinder. CONSTITUTION:One cam shaft 21 and one rocker shaft 22 are arranged at upper and lower positions intersecting at right angle for the axis line L of a cylinder 4. A pair of intake valves 10 are arranged at the one side of the cam shaft 21, a pair of exhaust valves 11 are arranged at the other side of a cam shaft 21. Two rocker arms 25 for the exhaust valves are provided at the inner side of the rocker shaft 22, two rocker arms 26 for intake valves are provided at the outer side of the rocker arms 22. The main body part 16b of an ignition plug 16 is contained in a space formed of the cam shaft 21, the rocker shaft 22, a pair of rocker arms 26 for intake valves and a pair of intake valves 10, also an electrode part 16a is arranged in the vicinity of the cylinder axis line L. Accordingly, the installing and removing of the plug 16 is easy, further, the electrode part can be arranged at the optimum location.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an OHC type valve operating system for a four-valve internal combustion engine having a pair of intake valves and an exhaust valve.

Generally, in an internal combustion engine, in order to spread the combustion flame of the air-fuel mixture caused by the spark discharge of the ignition plug quickly and evenly over the entire area from the center to the periphery of the combustion chamber, suppress knocking, and improve combustion efficiency, the ignition It is desirable to place the electrode of the plug in the center of the combustion chamber.

However, in the OII C type valve train of a conventional four-valve internal combustion engine, at least one valve train camshaft is rotatably supported in the cylinder head, and intake and exhaust ports are provided on both sides of the valve train camshaft. The two rocker arm shafts are fixedly fixed, and the intake and exhaust rocker arms are swingably supported on these rocker arm shafts, respectively, and these rocker arms are used to connect the intake and exhaust valve cams on the valve camshaft and each pair of rocker arms. It is configured to connect the intake and exhaust valves. Therefore, the space above the center of the combustion chamber is occupied by the valve camshaft, intake,
The exhaust rocker arm shaft, rocker arm, etc. are occupied without any gaps by many valve train parts, and there is not enough space to place the spark plug electrode in the center of the combustion chamber and to easily install and remove the spark plug. Conventionally, the spark plug had to be installed on one side of the combustion chamber to avoid the valve train group, and it was also difficult to install and remove the plug, and the valve train had a large number of parts. There were disadvantages such as increased size.

The present invention has been made in view of the above circumstances, and allows the spark plug to be placed in the center of the combustion chamber, making it easy to attach and detach, and reducing the number of parts in the valve mechanism, thereby achieving compactness and cost reduction. It is an object of the present invention to provide a valve operating system for an internal combustion engine that can perform the following steps.

According to the present invention, in order to achieve the above object, in a four-valve internal combustion engine, a cylinder head is fixed on a cylinder block, a cylinder bore into which a piston is slidably fitted is formed in the cylinder block, and a cylinder bore in which a piston is slidably fitted is formed in the cylinder block. , a combustion chamber facing the top surface of the piston is formed, a pair of intake valves are disposed on one half of the ceiling wall of the combustion chamber, and a pair of exhaust valves are disposed on the other half of the ceiling wall. In the four-valve internal combustion engine, a valve drive camshaft and a rocker arm shaft are disposed on the cylinder head orthogonally to the axis of the cylinder bore, and the valve drive camshaft operates the pair of exhaust valves. An exhaust cam and an intake cam that operates the pair of intake valves are integrally provided on both sides of the exhaust cam, and an exhaust side rocker arm that connects the pair of exhaust valves and the exhaust cam is provided on the rocker arm shaft, and an exhaust side rocker arm that connects the pair of exhaust valves and the exhaust cam, and the An intake side rocker arm that connects a pair of intake valves and an intake cam is swingably supported, and an electrode of a spark plug attached to the cylinder head is disposed in the center of the ceiling wall of the combustion chamber. A space for accommodating a main portion of a spark plug and for attaching and detaching the plug is defined between the valve operating camshaft, a rocker arm shaft, a pair of intake-side rocker arms, and a pair of intake valves.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a cylinder head 2 is overly bonded onto a cylinder block 1 via a gasket 3. As shown in FIG. A piston 5 interlocked with a crankshaft (not shown) is slidably fitted into a cylinder bore 4 formed in the cylinder block 1, and a combustion chamber 6 facing the top surface of the piston 50 is formed in the cylinder head 2. be done.

One half of the ceiling wall 7 of the combustion chamber 6 (top thin section in Figure 1)
A pair of intake ports 8, 8 are opened in parallel with each other, and a pair of exhaust ports 9, 9 are opened in parallel with each other in the other side half (bottom thin section in Fig. 1).
.
3, respectively, so as to be slidable. In this way, the four valves 10, 10; 11, 11 are arranged so as to surround the axis of the cylinder bore 4. These valves 10, 10; it, i
i is biased in the valve closing direction by valve springs 14, 14; 15, 15, respectively.

Further, an ignition plug 16 is screwed onto the cylinder head 2, and its electrode 16a faces the center of the combustion chamber 6 near the axis.

A cam case 17 is bonded to the cylinder head 2 via a sealing member 18, and the cams 'y-,z
, 17 fl head force bar 1s-7,: Polymerized and bonded via the seal member 20.

The cam case 17 is perpendicular to the axis of the cylinder bore 4.
A single valve drive camshaft 21 is rotatably supported on the shaft 21, and a rocker arm shaft 22 is fixedly supported in the vicinity of and parallel to the shaft 21. The valve train camshaft 21
As clearly shown in FIG. 3, on the central part of the cylinder bore 4, there is a wide exhaust cam 23 which jointly operates a pair of exhaust valves 11, 11, and a pair of intake valves io on both sides of the cam 23. , io are integrally provided. Further, one exhaust side rocker arm 25 is swingably supported on the rocker arm shaft 22'' in correspondence with the one exhaust cam 23, and the two intake cams 24. Two intake-side rocker arms 26, 26 are swingably supported in correspondence with 24. The exhaust-side rocker arm 25 has a cam slipper 25α at its base, and this cam slipper 25a The perpendicular line υ extending from the contact surface passes through the center of the valve drive camshaft 21.The tip of the exhaust side rocker arm 25 is bifurcated. The branch arms 25b, 251) are formed to be branched, and their ends are connected to the stem ends 11α, 11a of the pair of exhaust valves 11.11 via adjustment screws 27°27. The rocker arms 26.26 have at their base cam slippers 26.Z, 26.2, these cam slippers 26.alpha., 26a on the cam surfaces of the two intake cams 24.24, the valve springs 14.degree. 1
A perpendicular line υ2 that is brought into contact by the elastic force of 4 and extends from their contact surfaces passes through the center of the valve drive camshaft 21. Two intake side rocker arms 26. Arm portion 267 of 26! I, 26
5 are curved so as to approach each other, and their tips connect to a pair of intake valves 1 through adjustment screws 28° 28.
It is connected to stem ends 10a and 10α of 0 and 10.

The valve drive camshaft 21, the rocker arm shaft 22, the pair of intake side rocker arms 26, 26, and the pair of intake valves 10
．． A space for accommodating the main body portion 16A of the spark plug 16 and for attaching and detaching the plug 16 is defined between the spark plugs 10 and 10. A hollow cylindrical socket 31 is provided in the space 30, and a hollow cylindrical socket 31 is provided in the arm portion 264 of the intake side rocker arm 26.26.
．． 26b and is inserted so as to surround the upper part of the spark plug 16, the lower end of the socket 31 is fitted into the cylinder head 2, and the upper end is inserted into the seal member 32.
It is fitted and fixed to the head cover 19 via.

Next, the operation of this embodiment will be explained.

When the valve train camshaft 21 is rotated, the mountain portions of the pair of intake cams 24.24 move toward the intake side rocker arms 26.26.
Each time the rocker arm 26.26 is pushed, the rocker arm 26.26 swings about the rocker arm shaft 22, pushes down the intake valve 10.10 against the closing force of the valve springs 14, 14, and opens the intake valve 10.10. Also, each time the peak of the exhaust cam 23.23 pushes the exhaust side rocker arm 25.25, the rocker arm 25.
25 similarly swings about the rocker arm shaft 22 as a fulcrum, and pushes down the exhaust valves ii, ii against the closing force of the valve springs 15, 15 to open them.

Then, at the end of the compression stroke of the engine, when the air-fuel mixture in the combustion chamber 6 is ignited by the spark discharge from the ignition plug 16, the flame spreads from near the electrode 1εα of the ignition plug 16 to its surroundings. Since the electrode 16α is arranged approximately on the axis of the cylinder bore 4, the electrode 16α (from Z to the combustion chamber 6
Since the distances to each peripheral edge of the cylinder are approximately equal, the flame propagates to each part in a short time, resulting in good combustion without knocking.

The valve train camshaft 21 and the rocker arm shaft 22 are connected to each other.

Since they are commonly used to operate the exhaust side rocker arms 26, 25, 25, only one of each is sufficient, contributing to the simplification and weight reduction of the valve train structure.

In addition, each rocker arm 26, 25.25 is arranged so that the valve train camshaft 21 and the rocker arm shaft 22 are orthogonal to the axis of the cylinder bore 4, so that the arm lengths of each rocker arm 26, 25.25 are approximately equal, and the weight is also approximately equal. Since it is made equal,
It is possible to avoid a valve jumping phenomenon occurring during high-speed operation due to the weight being biased toward one rocker arm.

Further, when attaching and detaching the spark plug 16, a tool for attaching and detaching the spark plug 16 is inserted into the space 30 for accommodating and detaching the main portion 16A of the spark plug 16, that is, the socket 31. Thus, the socket 31 is connected to the valve train camshaft 21, the rocker arm shaft 22, the intake side rocker arm 26.
26 and between the intake valves 10° and 10, the spark plug 16 can be easily attached and detached without being obstructed by the electrodes 16α and 10.
can be placed in the center of the combustion chamber 6.

As described above, according to the present invention, in a four-valve internal combustion engine, although both the valve train camshaft and the rocker arm shaft are disposed orthogonal to the axis of the cylinder bore, they are located substantially on the axis of the cylinder bore, that is, in the combustion chamber. The electrode of the ignition plug can be placed in the center of the ceiling wall of the ignition plug, and the space for accommodating the main body of the ignition plug and its attachment/detachment is provided by the valve drive camshaft, rocker arm shaft, a pair of intake-side rocker arms, and a pair of intake-side rocker arms. Since the spark plug can be installed in the space surrounded by the intake valve, it enables optimal placement of the spark plug in the combustion chamber.
It is possible to significantly improve combustion efficiency by suppressing knocking, and it is possible to easily and easily attach and detach the spark plug without being hindered by the components of the valve train.
Improved maintainability. Furthermore, since the main body of the spark plug is disposed away from the exhaust side, which is heated to a high temperature, the influence of that heat is reduced, allowing the spark plug to operate accurately over a long period of time and extend its life.

Further, since only one valve drive camshaft and one rocker arm shaft are required, the number of parts of the valve train is reduced, and the device can be made lighter, more compact, and lower in cost.

[Brief explanation of the drawing]

The drawings show one embodiment of the device of the present invention, in which Fig. 1 is a longitudinal sectional side view thereof, Fig. 2 is a view taken along the line ■-■ in Fig.
The figure is a sectional view taken along the line III-III in FIG. 1. L...Axis 1...Cylinder block, 2...Cylinder head,
4... Cylinder bore, 5... Piston, 6... Combustion chamber, 7... Ceiling wall, 10... Intake valve, 11...
Exhaust valve, 16... Spark plug, 16α... Electrode, 1
6b...Main part, 21...Valve train camshaft, 22...
・Rocker arm shaft, 23...Exhaust cam, 24...Intake cam, 25...Exhaust side rocker arm, 25α...
Cam slipper, 25.6... Branch arm, 26... Intake side rocker arm, 3o... Space Patent Applicant Honda Motor Co., Ltd. Figure 2 Figure 3 Procedural Amendment Imported) February 1985 25th 1, Indication of the case 1982 Patent Application No. 66908 3, Person making the amendment Relationship to the case Name of patent issuer (532) Honda Motor Co., Ltd. 4, Agent
Person 105 Address 4-4-5 Shinbashi, Minato-ku, Tokyo 1st Nijimura Building Subject of 5 Amendment (2) Figure 4 of the drawings is added as attached. □、I
l-Description (full text amendment) 1. Name of the invention Valve operating system for internal combustion engine 2. Scope of claims ■ A cylinder head is fixed onto a cylinder block, and a cylinder bore into which a piston is slidably fitted is connected to the cylinder block. A combustion chamber facing the top surface of the piston is formed in the cylinder head, a pair of intake valves are provided on one half of the ceiling wall of the combustion chamber, and a pair of intake valves are provided on the other half of the ceiling wall of the combustion chamber. In a four-valve internal combustion engine each having an exhaust valve, a valve drive camshaft and a rocker arm shaft are disposed on the cylinder head to be orthogonal to the axis of the cylinder bore, and the valve drive camshaft is provided with a rocker arm shaft. , an exhaust cam that operates the pair of exhaust valves and an intake cam that operates the pair of intake valves are integrally provided on both sides of the exhaust cam, and the pair of exhaust valves and the exhaust cam are connected to the rocker arm shaft. [An air-side rocker arm and an intake-side rocker arm that connects the pair of intake valves and the intake cam on both sides thereof are swingably supported, and an electrode of a spark plug attached to the cylinder head is connected to the combustion chamber. The main body of the spark plug is housed in the center of the ceiling wall of the spark plug, and a space in which the main body of the spark plug is accommodated and where the plug is attached and detached is provided between the valve operating camshaft, the rocker arm shaft, the pair of intake-side rocker arms, and the pair of intake valves. A valve train for an internal combustion engine, characterized in that: (2) In the valve operating system for an internal combustion engine as set forth in claim (2), the exhaust-side rocker arm has a cam slipper at one end thereof that comes into contact with the exhaust cam, and a two-pronged rocker arm at the other end. A valve operating system for an internal combustion engine characterized by forming branch arms that are branched into two, and having both ends of the arms connected to stem ends of the pair of exhaust valves. 3. Detailed Description of the Invention The present invention relates to an OEC type valve operating system for a four-valve internal combustion engine having a pair of intake valves and an exhaust valve. Generally, in an internal combustion engine, in order to spread the combustion flame of the air-fuel mixture caused by the spark discharge of the ignition plug quickly and evenly over the entire area from the center to the periphery of the combustion chamber, suppress knocking, and improve combustion efficiency, the ignition It is desirable to place the electrode of the plug in the center of the combustion chamber. However, in the conventional OEC type valve train for a four-valve internal combustion engine, at least one valve train camshaft is rotatably supported in the cylinder head, and two valve train for intake and exhaust are installed on both sides of the valve train camshaft. Two rocker arm shafts are fixed, and rocker arms for intake and exhaust are swingably supported on the rocker arm shafts, respectively, and these rocker arms are used to connect the intake and exhaust valve cams on the valve drive camshafts, and each pair of intake and exhaust. The exhaust valve is configured to be connected to the exhaust valve. Therefore, the space above the center of the combustion chamber is occupied by the valve train camshaft and suction. The exhaust rocker arm shaft, rocker arm, and other valve train components are occupied without any gaps, and there is not enough space to place the spark plug electrode in the center of the combustion chamber and to easily install and remove the spark plug. Conventionally, the spark plug had to be installed on one side of the combustion chamber to avoid the valve train group, and it was also difficult to install and remove the plug, and the valve train had a large number of parts. There were disadvantages such as increased size. The present invention has been made in view of the above circumstances, and allows the spark plug to be placed in the center of the combustion chamber, making it easy to attach and detach, and reducing the number of parts in the valve mechanism, thereby achieving compactness and cost reduction. An object of the present invention is to provide a valve train for an internal combustion engine that enables the following. In order to achieve this object, the present invention connects a cylinder head to a cylinder block, forms a cylinder bore in the cylinder block into which a piston is slidably fitted, and also includes a top surface of the piston in the cylinder head. In a four-valve internal combustion engine, a combustion chamber is formed facing the combustion chamber, and a pair of intake valves are disposed on one half of the ceiling wall of the combustion chamber, and a pair of exhaust valves are disposed on the other half of the combustion chamber. A valve drive camshaft and a rocker arm shaft are arranged on the cylinder head to be perpendicular to the axis of the cylinder bore, and the valve drive camshaft includes an exhaust cam that operates the pair of exhaust valves, and an exhaust cam on both sides thereof. , intake cams for operating the pair of intake valves are each integrally provided, and the rocker arm shaft includes an exhaust-side rocker arm connecting the pair of exhaust valves and the exhaust cam, and an exhaust-side rocker arm that connects the pair of intake valves on both sides thereof. An intake side rocker arm connected to the intake cam is swingably supported, and an electrode of a spark plug attached to the cylinder head is arranged in the center of the ceiling wall of the combustion chamber, and the main body of the spark plug A space for accommodating the part and for attaching and detaching the plug,
It is defined between the valve drive camshaft, the rocker arm shaft, the pair of intake-side rocker arms, and the pair of intake valves. Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a cylinder head 2 is overly bonded onto a cylinder block 1 via a gasket 3. As shown in FIG. A piston 5 interlocked with a crankshaft (not shown) is slidably fitted into a cylinder bore 4 formed in the cylinder block 1, and a combustion chamber 6 facing the top surface of the piston 50 is formed in the cylinder head 2. be done. A pair of intake boats 8, 8 arranged in parallel with each other are located in the lower half of the ceiling wall 7 of the combustion chamber 6 (top narrow section in FIG. 1).
In addition, exhaust ports 9, 9 that are parallel to each other are opened in the other side half (bottom thin section in Figure 1), and these intake boats 8
, 8 and exhaust port 9°9, each pair of intake valves 10.10 and exhaust valves 1.1, . 11 is a valve guide 12, 12 and 1 provided in the cylinder head 2.
3.13, each is slidably mounted. In this way, the four valves 10.10; 11.11 are arranged so as to surround the axis of the cylinder bore 4. These 10,10;N
, 11 are biased in the valve closing direction by valve springs 14, 14; 15, 15, respectively. Further, an ignition plug 16 is screwed onto the cylinder head 2, and its electrode 16a faces the center of the combustion chamber 6 near the axis. On the cylinder head 2, a cam case 17 is superimposed and bonded via a seal member 18, and seven cam cases 17
A head cover 19 is bonded thereon via a sealing member 20. The cam case 17 is perpendicular to the axis gL of the cylinder bore 4.
A single valve drive camshaft 21 is rotatably supported on the shaft 21, and a rocker arm shaft 22 is fixedly supported adjacent to and parallel to the shaft 21. The valve train camshaft 21
As clearly shown in FIG. 3, above the center of the cylinder bore 4, there is a wide exhaust cam 23 that operates a pair of exhausts 9f11 and 11, and a pair of intake valves 10. A pair of intake cams 24, 24, each actuated separately, are integrally provided. Further, one lid air side rocker arm 25 is swingably supported on the rocker arm shaft 22 in correspondence with the one exhaust cam 23, and the two intake cams 24, 24 are supported on both sides of the exhaust side rocker arm 250. Two intake-side rocker arms 26, 26 are swingably supported correspondingly. The exhaust side rocker arm 25 has a cam slipper 25α at its base.
The cam slipper 25α has the exhaust cam 23
The valve spring 15 is attached to the cam surface of the valve spring 15. The perpendicular line v1 that is contacted by the elastic force of i5 and extends from the contact surface is the valve drive camshaft 21
passes through the center of The tip of the exhaust side rocker arm 25 is formed into two branched arms 25b, 25b,
Their ends are connected to the stem ends 11.alpha., 11.alpha. of a pair of exhaust valves 11.11 via adjustment screws 27.degree. 27. Further, the pair of intake side rocker arms 26, 2
6 have cam slippers 26a, 26a at their bases, these cam slippers 26a, 26a are attached to the cam surfaces of the two intake cams 24.24, and the valve springs 14.1
4, and the perpendicular line υ2 extending from their contact surfaces passes through the center of the valve camshaft 21. ,2
6h are curved so as to approach each other, and their tips connect to a pair of intake f through adjustment screws 28°28.
It is connected to the stem ends 10α and 10a of f10 and 10. Supplementary note Valve operating camshaft 21, rocker arm shaft 22, a pair of intake side rocker arms 26, 26, and a pair of intake valves 10.
10, the hollow cylindrical socket 31 of the spark plug 16 passes between the arm portions 26b, 26b of the intake side rocker arm 26.
The lower end of the socket 31 is fitted to the -7IJ head 2, and the upper end thereof is fitted and fixed to the head cover 19 via a seal member 32. Next, the operation of this embodiment will be explained. When the valve train camshaft 21 is rotated, the mountain portions of the pair of intake cams 24.24 move toward the intake side rocker arms 26.26.
Each time the rocker arm 26.26 is pushed, the rocker arm 26.26 swings about the rocker arm shaft 22, pushing down the intake valve 10.10 against the closing force of the valve springs 14, 14, and opening them. Also, each time the peak of the exhaust cam 23.23 pushes the exhaust side rocker arm 25.25, the rocker arm 25.
25 similarly swings about the rocker arm shaft 22 as a fulcrum, and pushes down the exhaust valves 11, 11 against the closing force of the valve springs 15, 15, thereby opening them. Then, at the end of the engine's compression stroke, the spark plug 1
When the air-fuel mixture in the combustion chamber 6 is ignited by the spark discharge of the spark plug 16, the flame spreads from near the electrode 16α of the spark plug 16 to the surrounding area.
Since the distances from the electrode 16α to each peripheral part of the combustion chamber 6 are approximately equal, the flame propagates to each part in a short time, resulting in good combustion without knocking. . The valve train camshaft 21 and the rocker arm shaft 22 are connected to each other. Since they are commonly used to operate the exhaust side rocker arms 26, 25.25, only one of each is sufficient, which contributes to simplifying the structure and reducing the weight of the valve train. In addition, each rocker arm 26, 25, 25 is arranged so that the valve train camshaft 21 and the rocker arm shaft 22 are orthogonal to the axis of the cylinder bore 4, so that the arm lengths of each rocker arm 26, 25, 25 are approximately equal, and the weight is also approximately the same. Since it is made equal,
It is possible to avoid a valve jumping phenomenon occurring during high-speed operation due to the weight being biased toward one rocker arm. Further, when attaching and detaching the spark plug 16, a tool for attaching and detaching the spark plug 16 is inserted into the space 30 for accommodating the main body portion 16h of the spark plug 16 and for attaching and detaching the same, that is, the socket 31. Thus, the socket 31 is connected to the valve train camshaft 21 as described above.
, the rocker arm 22, the intake side rocker arm 26.26, and the intake valve 10°10, the spark plug 16 can be easily attached and detached without being obstructed by them. This allows for placement in the center of the combustion chamber 6. Another embodiment of the invention is shown in FIG. In this embodiment, as is conventionally known, a pair of exhaust cams 23', corresponding to a pair of exhaust valves 11.11,
23' is integrally provided on the valve drive camshaft 21, and a pair of exhaust side rocker arms 25', 25' correspond to the pair of exhaust cams 23', 23'.
5'α are formed, and these cam slits 25
'α, 25'α are brought into contact with the cam surfaces of the corresponding exhaust cams 23', '23' by the elastic force of the valve springs 15, 15. Arm portion 2 of a pair of exhaust side rocker arms 25', 25'
5'h and 25'b are curved so that their tips are separated from each other, and those tips are connected to adjustment screws 2B and 2B.
Through the stem end 1 of the corresponding exhaust valve 11° 11.
It is connected to ia and 1iα. In this embodiment, except that the pair of exhaust valves 11, 11 are individually operated by a pair of exhaust cams 23', 23' via a pair of exhaust side rocker arms 25', 25'. Exactly the same effect as the embodiment shown above can be achieved. As described above, according to the present invention, in an open-valve type internal combustion engine, although both the valve train camshaft and the rocker arm shaft are disposed orthogonal to the axis of the cylinder bore, they are located substantially on the axis of the cylinder bore, that is, in the combustion chamber. The electrode of the ignition plug can be placed in the center of the ceiling wall of the ignition plug, and the space for accommodating the main body of the ignition plug and its attachment/detachment is provided by the valve drive camshaft, rocker arm shaft, a pair of intake-side rocker arms, and a pair of intake-side rocker arms. Since the spark plug can be installed in the space surrounded by the intake valve, it is possible to optimally place the spark plug in the combustion chamber, thereby suppressing knocking and greatly improving combustion efficiency. The plug can be easily attached and detached without being obstructed by the components of the valve train, which improves maintainability. Furthermore, since the main body of the spark plug is disposed away from the exhaust side, which is heated to a high temperature, the influence of that heat is reduced, allowing the spark plug to operate accurately over a long period of time and extend its life. Further, since only one valve drive camshaft and one rocker arm shaft are required, the number of parts of the valve train is reduced, and the device can be made lighter, more compact, and lower in cost. 4. Brief description of the drawings Figures 1 to 3 show the first embodiment of the device of the present invention, with Figure 1 being a vertical side view and Figure 2 taken along the line ■-■ in Figure 1. The arrow view and FIG. 3 are cross-sectional views taken along the line ■--■ in FIG. 1, and FIG. 4 is a cross-sectional view similar to FIG. 3 showing the second embodiment of the apparatus of the present invention. L... Axis line, 1... Cylinder block, 2... Cylinder head,
4... Cylinder bore, 5... Piston, 6... Combustion chamber, 7... Ceiling wall, 10... Intake valve, 11...
Exhaust valve, 16... Spark plug, 16α... Electrode, 1
6b...Main part, 21...Valve train camshaft, 22...
・Rocker arm shaft, 23° 23'...Exhaust cam, 24
...Intake cam, 25.25'...Exhaust side rocker arm, 25α...Cam slipper, 25b...Branch arm,
26...Intake side rocker arm, 3゜...Space Patent applicant Honda Motor Co., Ltd. Figure 4

Claims (1)

[Claims] ■ Cylinder head (2) on cylinder block (1)
and the piston (
The cylinder head (2) is formed with a combustion chamber (6) facing the top surface of the external piston (5). )
A pair of intake valves (io,
i o), and a pair of exhaust valves (11
. (22), and the valve drive camshaft (21) has an exhaust cam (23) that operates the pair of exhaust valves (11°11), and on both sides of the exhaust cam (23), the pair of intake valves (1o, Intake cams (24, 24) for operating the rocker arm shaft (22) are provided integrally with each other, and the rocker arm shaft (22)
includes the pair of exhaust valves (11, 11) and the exhaust cam (2).
3), and an intake rocker arm (26°2) that connects the pair of intake valves (10, 10) and the intake cam (24) on both sides thereof.
6) is swingably supported, and the cylinder head (2)
The electrode (16α) of the spark plug (16) attached to the
A space (30) is provided in the center of the ceiling wall (7) of the combustion chamber (6), and accommodates the main portion (16b) of the spark plug (16), and in which the plug (16) is attached and detached. , an internal combustion engine characterized in that the valve drive camshaft (21), the rocker arm shaft (22L) are defined between a pair of intake side openings (26, 26) and a pair of intake valves (10°10). Valve drive system. ■ In the drive system for an internal combustion engine as set forth in claim 0, the exhaust side rocker arm (25) has a cam slipper (25) at one end thereof that abuts the exhaust cam (23). 25tl), and bifurcated branch arms (25A, 25b) are formed at the other end, and these arms C
25b, 25b) to the pair of exhaust valves (11,j
A valve train for an internal combustion engine, characterized in that the valve train is connected to each of the stem ends of (l).