JPS60187706A - O.h.c. type valve gear for four valve type internal-combustion engine - Google Patents

Abstract

PURPOSE:To arrange an ignition plug at the central section of a cylinder, and to simplify a valve mechanism by disposing a cam shaft and a rocker shaft on the cylinder axis of a cylinder head cover one by one and up and down and driving a pair of intake and exhaust valves. CONSTITUTION:A pair of intake and exhaust valves 10, 11 are arranged so as to surround a cylinder axis A, and a cam shaft 24 and a rocker shaft 26 are installed vertically to a heat cover 17 in parallel with the direction of arrangement of valves of the same kind as the intake and exhaust valves 10, 11. Two rocker arms 30 driving the intake valve 10 are mounted to the rocker shaft 26 so as to hold a rocker arm 31 driving the exhaust valve 11, and a space in which an ignition plug 16 is fitted is formed between the two rocker arms 30 for the intake valve. The ignition plug 16 can be disposed on the cylinder axis A, only the cam shaft and the rocker shaft may be used severally, a valve mechanism can be simplified, the mechanism can be assembled previously to the head cover and assembly is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an open-gate internal combustion engine, in particular, a pair of intake valves and an exhaust valve mounted on a cylinder head are arranged so as to surround the axis of the cylinder, and a spark plug mounted on the cylinder is arranged so as to surround the cylinder axis. 0.0 of the engine with the electrode facing the combustion chamber near the axis. Il
, relating to a C0 type valve train.

In the 0, Il, C, type valve train, a single camshaft is disposed perpendicular to the axis of the cylinder, S, o, H, c.

OJi, C has a type valve train and two camshafts, one for intake and one for exhaust, arranged close to the intake and exhaust valves, respectively.

There is a type valve train, but the former uses a camshaft and suction.

Two rocker shafts that support the intake and exhaust rocker arms for connection with the exhaust valve are installed on both sides of the camshaft, so the ignition plug electrodes are interfered with by the camshaft and rocker shaft. Although it is difficult to locate the camshaft near the cylinder axis where conditions are favorable for combustion, the structure of the timing transmission device that drives the camshaft from the crankshaft is simple, and only one particularly heavy camshaft is required. This is advantageous in reducing the weight of the engine, whereas in the latter case, the spark plug electrode can be easily placed near the cylinder axis without being interfered with by the two camshafts, improving the engine's output performance. However, the structure of the timing transmission becomes more complicated and the weight of the engine increases, so each has its advantages and disadvantages.

Therefore, the present invention makes it possible to arrange the electrode of the spark plug near the cylinder axis even though there is only one camshaft, and in addition, only one rocker shaft is required. It is an object of the present invention to provide a valve operating system that is simple in structure, lightweight, and easy to assemble and maintain, by allowing an assembly of the valve operating system to be configured as described above.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. First, in FIG. are polymerized and bound together. A piston 5 is slidably fitted into each cylinder 1, and a combustion chamber 6 is recessed in the bottom surface of the cylinder head 3 facing the piston 5.

The ceiling surface of each combustion chamber 6 is constituted by two roof-shaped slopes γa and 7b that intersect at a ridge line L (see FIG. 1A) extending in the direction in which the plurality of cylinders 1 are arranged. One slope 7
A pair of intake boats 8°8 are attached to the other slope 7b.
Similarly, a pair of exhaust ports 1-9, 9 are opened side by side along the ridgeline, and each pair of intake ports 1-9, 9 are opened and opened in order to open and close these intake boats 8, 8 and exhaust ports 9, 9. Valve 10.10 and exhaust valve i1. ii is the valve guide 12, 12 and 13 provided in the cylinder head 3;
．． 13, respectively, so as to be slidable.

In this way, the four valves 10, 10; 11, 11 are arranged so as to surround the axis A of the cylinder 1. These valves 10,1
0; 11, 11 are valve springs 14° 14; 15, 1 respectively
5 in the valve closing direction.

Further, an ignition plug 16 is screwed onto the cylinder head 3, and its electrode 16α faces the combustion chamber 6 in the vicinity of the axis A.

A roof-shaped head cover 17 is provided on the top surface of the cylinder head 3.
are polymerized via the seal ring 18 and are fastened together by a plurality of bolts 19, 19, . . . .

Inside this head cover 17 are the intake and exhaust valves io,
io;i1. A valve operating device 20 of the present invention is provided which provides a valve opening operation to ii, and has the following configuration.

The head cover 17 has a plurality of support walls 21.21 arranged on its inner surface in the ridge direction and extending in the vertical direction.
... are integrally formed, and these supporting walls 21, 2
1... have bearing holes 22 parallel to the ridge line L, respectively.
．． 22... and shaft holes 23, 23... are bored.

At that time, bearing holes 22.22... and shaft holes 23.23...
・ are arranged so that their respective axes are substantially perpendicular to the axis A, and the shaft holes 23, 23, . . .
．． 22... is arranged below.

The camshaft 24 is fitted into the bearing holes 22, 22, . . . from one end side of the head cover 17 so that the plurality of journals 24, 24, . . . are supported on their inner walls. The camshaft 24 is driven by a crankshaft (not shown) via a well-known timing transmission 25 at an end projecting outward from one end surface of the head cover 17.

As shown in FIG. 2, the camshaft 24 has a pair of adjacent exhaust cams 24e corresponding to each cylinder 1.

24C1 and a pair of intake cams 24i, 24i arranged on the outside of the plane of these exhaust cams 24C, 24g are formed between adjacent journals 24, 24.

A rocker shaft 26 is fitted into the shaft holes 23, 23, . . . from one end side of the head cover 17, and its insertion opening 27 is closed with a cap 28, as shown in FIG. In order to prevent this rotation and axial movement of the rocker shaft 26, the tip of a bolt 27 screwed onto a portion of the support wall 21 is fitted into the side wall of the rocker shaft 26.

The rocker shaft 26 is connected to the intake valve 10 corresponding to each cylinder 1.
．． 10, intake cams 24i, 24i, exhaust valve i1. ii and exhaust cam24. A pair of bell-crank-shaped intake rocker arms 30.30 and exhaust rocker arms 31.31, which are connected to each other between + and 24g, are swingably supported.

It engages with the intake cams 24i, 24i located on the outer side of the circle.

A space 49 for attaching and detaching the spark plug 16 is provided between the pair of intake rocker arms 30, 30 by taking advantage of the relatively wide spacing between them. In order to define this space 49, a cylindrical socket 5.0 is disposed so as to surround the upper part of the ignition plug 16 and pass between both the intake rocker arms 30, 30, and the lower part of the socket 50 is connected to the cylinder. The head force bar 1 is fitted onto the head 3, and its upper end is connected to the head force bar 1 through a sealing member 51.
7 is fitted.

At the end of each rocker arm 30.31 on the side of the valve 10.11, a pole 32.33 for adjusting the valve head gap is screwed, and furthermore, lock nuts 1-34, 35 are screwed into these bolts 32, 33. There is.

When adjusting the valve head clearance of each intake and exhaust valve 10.11,
With a thickness gauge of a predetermined thickness inserted between the lower parts of the opposing cams 24i and 24e and the slipper surface of the rocker arm 30.31, the adjusting bolt 32.33 of the rocker arm 30.31 is screwed in or out. Retract and touch the head KW of intake and exhaust valve 10.11, locking) 34.35
Tighten the adjustment bolts 32, 330 to fix the adjustment positions. Then, by pulling out the tightness gauge, a predetermined valve head clearance can be obtained.

In order to insert a tool for such adjustment work into the head cover 1f, the head cover is provided with a first window 36 facing each set of intake and exhaust cams 24b, 24b; 24e, 24e. Also, the adjustment bolt 32 of each intake rocker arm 30
A second window 37 is located opposite to the exhaust rocker arm 31 .
A third window 38 is bored opposite the adjustment bolt 33 .

During normal times, these windows 36°37.38 are covered with caps 39,
40.41 and closed respectively.

The rocker shaft 26 is formed hollow, and the hollow portion 26
d is connected to a lubricating oil supply source (not shown) as an oil path.

A portion of the rocker shaft 26 that supports each rocker arm 30.31 is provided with an outer circumferential groove 42, and a horizontal hole 43 communicating with the hollow portion 26 (Z) in the outer circumferential groove 42. The boss of the rocker arm 30
．． 31 and the engaging portions of the cams 241 and 24C, as well as the adjusting bolts 32 and 33.

First oil injection holes 44 and 45 and second oil injection holes 46 and 47, which respectively face the contact portions with the exhaust valves io and ii, are provided so as to communicate with the outer circumferential groove 42, respectively.

Therefore, when lubricating oil is pumped into the hollow part 24α of the camshaft 24, the oil moves from the horizontal hole 43 to the outer circumferential groove 42, lubricates the inner surface of the boss of each rocker arm 30.31, and also lubricates the inner surface of the boss of each rocker arm 30.
and ejects from the second oil injection holes 44, 45; 46.47,
Each engagement part between the rocker arm 30.31 and the cams 24L and 24g, as well as the adjustment bolt 32.33 and the intake and exhaust valves io,
It is supplied to each contact portion with i1 to lubricate these.

On the inner surface of the head cover 17, there is an oil trap 4 that hangs down to just above the end of the exhaust rocker arm 31 on the camshaft 24 side.
8 is integrally protruded, and the rotation direction of the camshaft 240 is indicated by the arrow R.
The upper side thereof is directed toward the oil trap 48, as shown in FIG. Therefore, when the lubricating oil attached to each cam 24L, 24e is scattered by centrifugal force and attached to the oil trap 48 while the camshaft 240 is rotating, the oil flows down along the vertical surface of the oil trap 48. The rocker arm 31.31 and exhaust transfer cam 24e below it.

24e to lubricate them.

Next, the operation of this embodiment will be explained.

When the camshaft 24 is rotated by the timing transmission 25, each time the peaks of the intake cams 24i, 24i push the intake rocker arm 30.30.
30 swings counterclockwise in FIG. 1 with the rocker shaft 26 as a fulcrum, pushes down the intake valve 10°10 against the closing force of the valve springs 14, 14, opens these valves, and also moves the exhaust cam 10. 2
Every time the peak of 48.24g pushes the exhaust rocker arm 31.31, the rocker arm 31.31 similarly swings clockwise in FIG. is pushed down against the valve closing force of the valve springs 15, 15 to open them.

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, a flame is emitted from the electrode 16 of the ignition plug 16. It spreads from the vicinity to the surrounding area, but as mentioned above, the electrode 16. Since z is arranged approximately on the axis A of the cylinder 1, the distances from the electrode 16a to each peripheral part of the combustion chamber 6 are approximately equal, and therefore the flame propagates to each part in a short time, resulting in a good combustion without knocking. Combustion is obtained.

In this way, the camshaft 24 and the rocker shaft 26 are in a suction position.

Since they are commonly used for the operation of the exhaust rocker arms 3 [J, 31, one each is sufficient, which contributes to the simplification and weight reduction of the structure of the valve train 20.

\ Moreover, since the camshaft 24 and rocker shaft 26 are arranged so as to be orthogonal to the axis A of the cylinder, the rocker arms 30, 31 have approximately the same arm length, and therefore have approximately the same weight. , the weight is biased towards one rocker arm. This makes it possible to avoid the valve jumping phenomenon during high-speed operation.

Further, the camshaft 24 and the rocker shaft 26 are connected to the head cover 17.
Therefore, when assembling the engine, the camshaft 24, rocker shaft 26, and rocker arms 30, 31 are attached to the head cover 17 in advance to form the valve train 200 assembly, and the head cover 17 is assembled into the engine. If the line is connected to the cylinder head 3, the valve train 20 is connected to the intake and exhaust valve 1o.

11 all at once, thus improving the efficiency of engine assembly work. Furthermore, if the head cover 17 is removed, the valve train 20 can also be removed from the cylinder head 3 side by IW [L].
Therefore, inspection, repair, etc. can be easily carried out.

When attaching and detaching the spark plug 16, a tool for attaching and detaching the spark plug 16 is inserted into the attaching and detaching space 49 of the spark plug 16, that is, the socket 50. As described above, the socket 50 is disposed between the rocker arms 30 and 30 disposed on both outer sides, and the rocker shaft 26 is located between the cam shaft 24 and the cam shaft 24, which does not interfere with the socket 50.
0, so the camshaft 24 and rocker shaft 2
6. Rocker arm 30.31 and intake and exhaust valves 10.11
The ignition plug 16 can be easily attached and detached without being obstructed by anything, and therefore the electrode 16a can be placed near the cylinder axis A.

In the above embodiment, the intake and exhaust cams 24L.

The position of 24e may be changed, and the exhaust valve 11 may be disposed on the spark plug 16 side, and the intake valve 10 may be disposed on the opposite side.

As described above, according to the present invention, the head cover adhered to the upper surface of the cylinder head has a bearing hole extending in the direction in which the intake and exhaust valves are arranged substantially perpendicular to the @ line of the cylinder, and a bearing hole extending below the bearing hole. A shaft hole extending parallel to the shaft hole is drilled, and a single camshaft connected to the intake and exhaust valves via a rocker arm is rotatably fitted into the bearing hole, and the rocker arm is rotated into the shaft hole. A freely supported rocker shaft is attached, a pair of rocker arms connected to each pair of intake valves or exhaust valves are placed on both outsides of the other rocker arms, and the ignition plug can be attached and detached between the pair of rocker arms. Because of the space provided, it is possible to arrange the spark plug electrode near the cylinder axis even though only one camshaft is required.Furthermore, since only one rocker shaft is required, the conventional 5.0. The structure is simpler and lighter than the H and C0 type valve train, and there is no possibility of the jumping phenomenon of the intake and exhaust valves occurring. Furthermore, the valve opening device can be assembled on the head cover before being attached to the cylinder head, thereby significantly improving assemblability and maintainability.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the main parts of an internal combustion engine equipped with an apparatus according to an embodiment of the present invention, Figure A is a bottom view of the cylinder head in Figure 1, and Figure 2 is a Figure 3 is a partial cross-sectional bottom view of the head cover in Figure 1. ... Cylinder head, 6... Combustion chamber, 1o... Intake valve, 11
...Exhaust valve, 16...Ignition plug, 16α...Electrode, 17
...Head cover, 2o...Valve train, 21...
Support wall, 22...Bearing hole, 23...Shaft hole, 24...
・Camshaft, 24g...exhaust cam, 24O...intake cam, 24]...journal, 25...timing transmission, 26...rocker shaft, 3゜...intake rocker arm,
31...Exhaust rocker arm, 49...Space for installing and removing spark plug, 5o...Socket Patent applicant Honda Motor Co., Ltd.

Claims (1)

[Claims] Each pair of intake valves and exhaust valves attached to the cylinder head are arranged so as to surround the axis of the cylinder, and the electrodes of the spark plug attached to the cylinder head are arranged near the axis to face the combustion chamber. In the open-gate internal combustion engine, a head cover fixed to the upper surface of the cylinder head has a bearing hole extending in a direction in which the intake and exhaust valves are arranged, substantially perpendicular to the axis of the cylinder, and a bearing hole extending in the direction in which the intake and exhaust valves are arranged, and A camshaft connected to the intake and exhaust valves via a rocker arm is rotatably fitted into the bearing hole, and the rocker arm is inserted into the shaft hole. A one-piece force shaft that swingably supports the is mounted, and a pair of rocker arms connected to each pair of intake valves or exhaust valves are arranged on the outside of the surface of the other rocker arm, An O, ILC, type valve train for an out-of-gate internal combustion engine, comprising a space for attaching and detaching the spark plug between the rocker arms.