JPS6035106A - Internal combustion engine valve train - Google Patents

Abstract

PURPOSE:To make the captioned equipment compact by interlocking a cam shaft, which is arranged in a gathered manner on each one side of both an air- inlet valve and an air exhaust valve, with the other side of the said both valves via the cam follower and interlocking mechanism and moreover by engaging a part of the cam follower with the operation end of a hydraulic tappet. CONSTITUTION:A tappet mechanism A in a V-shaped multi-cylinder engine is formed by installing a cam shaft 21 in a freely rotatable manner at nearly just above an intake valve 10 and by arranging the first cam follower 25 between an intake cam 21i and an intake valve 10 head part together with arranging the second cam follower 31 on the exhaust valve 11 side of an exhaust cam 21e. The cam follower 31 is provided in such a manner that the middle part of one side of it is engaged with the exhaust cam 21e, while the upper end part of the other side of it is interlocked with the exhaust valve 11 via an interlocking mechanism M, and at the same time the lower end part of the other side is supported by a spherical operation end 40a of a hydraulic tappet 40. And the interlocking mechanism M is formed with a push rod 34 and a bell-crank-shaped locker arm 33.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a valve operating system for an internal combustion engine, particularly an intake valve and an exhaust valve that are disposed across a plane that includes the axis of a cylinder, and a single camshaft that drives these valves. The so-called 0. Regarding H, C, type valve train.

In the 0, Il, and C type valve train, one camshaft is disposed approximately along the plane including the axis of the cylinder.

With the H0C0 type valve train, two camshafts for intake and exhaust are arranged close to the intake and exhaust valves, respectively, and O, H
There is an oC type valve train, but in the former, it is extremely difficult to place the spark plug near the cylinder axis where the conditions are favorable for combustion due to interference with the camshaft, but the camshaft is driven from the crankshaft. The structure of the timing transmission is simple, and only one camshaft, which is difficult to process, is required, which is advantageous in reducing production costs.In contrast, the latter is advantageous in reducing production costs because it is not interfered by both camshafts and is located near the cylinder axis. It is possible to improve the output performance of the engine by arranging a spark plug, but this inevitably complicates the structure of the timing transmission and increases production costs, so each method has its advantages and disadvantages.

The present invention incorporates only the advantages of the above two types of valve gears, allows the ignition plug to be placed near the cylinder axis even though there is only one camshaft, and also automatically adjusts the valve head gap. It is an object of the present invention to provide the above-mentioned valve operating device that can always open and close a valve quietly and reliably, without any problems.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings.The internal combustion engine shown in FIG. 1 is a V-type multi-cylinder engine.
It has C2. Since the structures of both cylinder rows C, , C2 are symmetrical, only the left cylinder row C1 will be described below.

A cylinder head 3 is superimposed and bonded to the upper surface of a cylinder block 2 having a cylinder 1 via a gasket 4. A piston 5 is slidably fitted into the 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 7 of the combustion chamber 6 consists of two ceiling slopes 7a and 7h that descend on both sides from the ridge line passing on or near the axis Ac of the cylinder 1, and one ceiling slope 7a has a pair of intake boats. 8, 8, and the same on the other ceiling slope 7h (a pair of exhaust ports 9.9 are opened side by side along the ridge line. These intake bows) 8.8 and exhaust port 9.9 are opened and closed. Each pair of intake valves 10.1
0 and exhaust valves 11.11 are slidably supported in valve guides 12.12 and 13.13 provided in the cylinder head 3, respectively. At that time, the intake valve 10.1
0 is disposed on the valley r side between both cylinder rows C,, C25-, and the exhaust valve 11.11 is disposed on the opposite side thereof, and both valves 10.11 are tilted in mutually opposite directions with respect to the ~ plane P. .

As shown in FIGS. 2 and 4, an ignition plug 14 with an electrode facing the combustion chamber 6 is screwed onto the cylinder head 3, and this ignition plug 14 has intake and exhaust valves 10°, 10; 11, 11. It is arranged approximately along the cylinder axis Ac so that it is surrounded by.

The cylinder head 3 has a combustion chamber 6 formed therein and a spark plug 1.
4 is screwed onto the head body 15, and this head body 15
It consists of a bearing pedestal 16 which is overlappingly bonded to the upper surface of the bearing pedestal 16, and a head cover 17 which is further overlappingly bonded to the upper surface of this bearing pedestal 16 and defines a valve chamber 18 between it and the head body 15. 18 includes the intake valve 10.10 and the exhaust valve 11.1.
1 is provided with a valve train A of the present invention that provides an opening/closing operation,
It has the following structure.

6- The intake valve 10.10 and the exhaust valve 11.11 are fitted with valve springs 19, 19 and 20.20, respectively, which urge them toward the closing side.

Almost directly above the intake valve 10.10, therefore the cylinder axis A
At a position closer to the valley V than C, a single camshaft 21 is disposed parallel to the plane P and interlocks with a crankshaft (none of which is shown) via a timing transmission. 21 connects the journal 21 to the bearing stand 16 and the shaft 22
．． It is rotatably sandwiched between bearing caps 24 bound together by 23.

Placing the camshaft 21 on one side toward the valley V side in this manner is effective in reducing the maximum outer dimensions of both cylinder rows C1 and C2 as much as possible, thereby reducing the size of the V-type machine.

As shown in FIG. 3, the camshaft 21 has a pair of intake cams 21 corresponding to the intake valves 10.10 and exhaust valves 11.11.
i, 21i and exhaust cams 212, 21g, the intake cams 21i, 21i are arranged adjacent to the journal 21 on both sides thereof, and the exhaust cams 21e, 21C are further arranged on both sides thereof.

A pair of first cam followers 25.25 are interposed between the intake cams 21B and 21T and the head of the intake valve 10.10.

The proximal end of the first cam follower 25.25 is swingably supported by each spherical operating end 38a of a pair of first hydraulic tappets 38 mounted in the support hole 37.37 of the head body 15.

Further, the exhaust cams 21e, 21e of the camshaft 21 are engaged with one side intermediate portion of the pair of second cam followers 31.31 on the exhaust valve 11.11 side. This second cam follower 31
．． The upper end of the other side of 31 is connected to the exhaust valve 11.11 via a pair of interlocking mechanisms M, M, and the lower end of the same side is
A pair of second holes attached to the support holes 39 and 39 of the bearing stand 16
The hydraulic tappets 40, 40 are swingably supported at each spherical working end 40a.

Each interlocking mechanism M includes a bushing rod 34 that engages with two ends of the other side of the second cam follower 31, and a bell crank type rocker arm 33 that engages the bushing rod 34 at one end and engages the full exhaust valve 11 at the other end. It consists of
The rocker arm 33 is swingably supported by a support shaft 29 arranged parallel to the camshaft 21 and fixed to the bearing stand 16 with bolts 30 .

A guide protrusion 31α is integrally formed at the upper end of each second cam follower 31, and the guide protrusion 31a is slidable in a guide groove 41 provided on the cylinder head 3 and extending in the swinging direction of the second cam follower 31. is engaged with. In the illustrated example, the guide groove 41 is provided in a single common guide plate 42 that is fixed to the bearing cap 24 using the bolt 22.
It can also be provided directly on the bearing cap 24.

9- The tool hole 35 used for attaching and detaching the spark plug 14 has both bushing rods 34, 34, both hydraulic tappets 38.
40, in the area surrounded by the support shaft 29, the guide plate 42, etc., from the cylinder head 30 ignition plug 14 attachment part to the head cover 16
A portion of the tool hole 35 extending through the outer surface and penetrating the valve operating chamber 17 is formed by a partition cylinder 36 interposed between the head cover 16 and the bearing stand 16. In this case, the support shaft 29 is offset toward the exhaust valve 11.11 side, and both bushing rods 34.34 and both hydraulic tabs 38.4
0 is engaged with the exhaust cams 21g and 21g located on both sides, ensuring a wide gap between them, so that the tool hole 3
5 can be formed to have a sufficient size so that the spark plug 14 can be easily attached and detached.

Next, the operation of this embodiment will be explained. During operation of the engine, the camshaft 21 is rotationally driven by the crankshaft via a timing transmission (not shown). Then, when the intake stroke of the screw 10-ton 5 starts, the intake cam 21B starts.

The peaks of 21t swing the first cam followers 25.25 toward the intake valves 10.10 using each operating end 38a of the first hydraulic tab (38.38) as a fulcrum, so that the intake valves 10.10 The valve opens against the elastic force of the valve spring 19.19, and at the end of the intake stroke, the intake cam 21t,
Since the peak 21't passes the first cam follower 25.25, the intake valve 10.10 is closed by the elastic force of the valve springs 19,19. During this time, an air-fuel mixture is drawn into the combustion chamber 6 from an air-fuel mixture generating device such as a carburetor (not shown) through the intake boats 8, 8.

When the piston 5 approaches the end of its compression stroke, the compressed gas in the combustion chamber 6 is ignited by the spark discharge from the spark plug 14, and the piston 5 moves to the expansion stroke. At this time, since the ignition plug 14 is located at or near the cylinder axis Ac, the flame propagation distance from the ignition point to each peripheral edge of the combustion chamber 6 is approximately equal, so the combustion time is shortened to the minimum and high output is achieved. is demonstrated.

When the exhaust stroke of the piston 5 is started, the exhaust cam 21e
, 21e push the second cam follower 31° 31 toward the bushing rod 34, 34.

Then, the cam follower 31.31 becomes the second hydraulic tab)4
The bushing rods 34 and 34 are swung around the operating ends 40a of 0 and 40 as fulcrums, and their swiveling posture is properly maintained by the engagement of the guide protrusion 31σ and the guide groove 41. will be prevented from falling over. The bushing rod 34.3 is thus pushed by the second cam follower 31.31.
4 swings the rocker arm 33.33 towards the exhaust valve 11.11, which causes the exhaust valve 11.11 to move towards the valve spring 2.
The valve opens against an elastic force of 0.20, and at the end of the exhaust stroke, the peaks of the exhaust cams 21e and 21e touch the second cam follower 3.
1.31, the exhaust valve 11.11 is closed by the elastic force of the valve spring 20.20. During this time, combustion chamber 6
Exhaust gas is discharged from the exhaust boat 9°9.

When the intake valve 10.10 and the exhaust valve 11.11 are closed, if a gap is generated between each valve head, the corresponding first and second hydraulic tappets 38, 38; The ends 38α, 38α; 40.2° 401Z press the base ends of the corresponding cam followers 25, 25; 31° 31 to eliminate the valve head gap.

The ignition plug 14 is attached and detached by inserting a special tool into the tool hole 35, fitting it into the head of the ignition plug 140, and rotating the tool.

In addition, in the second invention, contrary to the above embodiment, the camshaft 21 and the first . 2nd cam follower 25.31 to exhaust valve 1
1 side, the rocker arm 33 can be arranged on the intake valve 10 side, and the exhaust cams 13-1 21e, 21e can be arranged adjacent to both sides of the journal 21,
It is also possible to arrange the intake cams 21i, 21i on both sides thereof. Further, the number of intake and exhaust valves used is not limited, and the present invention can be applied to, for example, one intake and one exhaust valve each.

As described above, according to the present invention, the camshaft is arranged to be offset to one of the intake and exhaust valves, and the middle part of one side of the cam follower is engaged with the camshaft, and the one end of the inducing side is engaged with the camshaft. The cam follower is connected to the other of the intake and exhaust valves via an interlocking mechanism, and the other end of the other side of the cam follower is swingably engaged with the operating end of a hydraulic tappet supported by the cylinder head. Since the cam follower is slidably engaged with a guide groove provided in the cylinder head and extending in the swinging direction of the cam follower, even though a single camshaft is used, it does not interfere with the camshaft (ignition plug). It is possible to arrange the cylinder 14 near the axis of the cylinder 14, and the timing transmission can be easily constructed, contributing to the downsizing and cost reduction of the engine.Furthermore, the cam follower has a guide groove that allows the cam follower to have a swing path. In order to be regulated correctly, the valve opening force of the camshaft must be reliably transmitted to the distant valve via the interlocking mechanism, and this can be opened and closed accurately, and the base end position of the cam follower must be controlled by a hydraulic tappet. By,
It is possible to eliminate the valve head gap that occurs in the relatively long valve opening force path from the camshaft to the distant valve, and it can also contribute to reducing the operating noise of the valve mechanism.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of the main parts of an internal combustion engine according to an embodiment of the present invention, Fig. 2 is a bottom view of the cylinder head in Fig. 1, and Fig. 3 is a cylinder head shown with the head force bar removed. 1
The enlarged plan view of the figure, Figures 4 and 5 are the TV-T of Figure 3.
They are sectional views taken along the V line and the -V line. A... Valve gear, Ac... Cylinder axis, AI...
・Interlocking mechanism, P...plane 1 including the cylinder axis...
Cylinder, 10... Intake valve, 11... Exhaust valve, 14
... Spark plug, 18 ... Valve chamber, 21 ... Camshaft,
31...Cam follower, 33...Rocker arm, 3
4... Butsch rod, 40... Hydraulic tappet, 4
1... Guide groove patent applicant Honda Motor Co., Ltd. Figure 2, Figure 3

Claims (1)

[Claims] In a valve operating system for an internal combustion engine, the cylinder head is provided with an intake valve and an exhaust valve disposed across a plane that includes the axis of the cylinder, and a single camshaft that drives these valves. The cam follower is arranged so as to be biased towards one of the intake and exhaust valves, and the middle part of one side of the cam follower is engaged with this camshaft, and the one end of the other side of the cam follower is connected to the other side of the intake and exhaust valves through an interlocking mechanism. The cam follower is connected to the valve, and the other end of the other side of the cam follower is swingably engaged with an operating end of a hydraulic tappet supported by the cylinder head, and the cam follower is connected to the cam follower provided on the cylinder head. A valve train for an internal combustion engine, characterized in that the valve train is slidably engaged in a guide groove extending in a swinging direction of the valve.