JPH0219524Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a valve operating system for a cross-flow three-valve internal combustion engine.

Conventionally, a cross-flow type three-valve combustion chamber is provided on the inner surface of the cylinder head, facing the upper surface of the piston that is slidable in the cylinder, and two intake valves and one exhaust valve are provided on the roof surface of the combustion chamber. type internal combustion engines are known. (Refer to Japanese Patent Application Laid-open No. 56-50209)
Such internal combustion engines have the advantage of high intake efficiency and high output, but the number of valves per cylinder and the number and types of rocker arms to operate them are large, and it is difficult to assemble them incorrectly. It was undeniable that the overall cost would be higher, such as the work involved in assembling the new model was more labor-intensive than the conventional one.

Therefore, the present invention makes it possible to share the three rocker arms for intake and exhaust in the valve train by forming them in the same way, and also changes the configuration of the valve train by specifying the arrangement of these rocker arms. without applying excessive force to any part of the
It is an object of the present invention to provide a valve train for a three-valve internal combustion engine that ensures smooth and light operation of the valve train while reducing the cost of the valve train.

According to the present invention, in order to achieve the above object, in a cross-flow type three-valve internal combustion engine, the valve drive camshaft is disposed approximately on the axis of the cylinder, and two rocker arms for intake are arranged adjacent to each other on the rocker arm shaft. one rocker arm for the exhaust is placed adjacent to the intake rocker arm near the center of the cylinder and biased to the other side of the combustion chamber, All three rocker arms are formed identically so that they are compatible.

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

First, a first embodiment of the present invention will be explained with reference to FIGS. 1 to 3. The engine body E of a cross-flow type three-valve internal combustion engine has a cylinder block 1 and a cylinder block 1 which is polymerized and bonded to the cylinder block 1 through a gasket 3. A piston 5 is slidably fitted into a cylinder 4 which is bored in the cylinder block 1. Further, a combustion chamber 6 facing the upper surface of the piston 5 is formed on the inner surface of the cylinder head 2, and a roof surface 7 of the combustion chamber 6 is formed in the shape of a roof with opposing inclined surfaces. Two intake valve ports 8 of the same diameter are provided on one side of the roof surface 7 of each combustion chamber 6.
a and 8b are opened in parallel, and an exhaust valve port 12 and a plug mounting hole 15 having a diameter slightly larger than the intake valve ports 8a and 8b are bored in parallel on the other side. The exhaust valve port 12 faces one intake valve port 8a, and the plug mounting hole 1
5 faces the other intake valve port 8b.

Intake ports 9a and 9b formed in the cylinder head 2 are communicated with the two intake valve ports 8a and 8b, and these intake ports 9a and 9b are gathered into one in the cylinder head 2 and connected to the cylinder head. 2, and communicates with a fuel supply device, for example, a carburetor 10, via an intake manifold In. Further, one exhaust valve port 12 is communicated with an exhaust port 13 formed in the cylinder head 2, and the exhaust port 13 is opened on the other side of the cylinder head 2 and communicated with the exhaust system via an exhaust manifold Em.

Further, an ignition source, that is, a spark plug P is screwed into the plug mounting hole 15 from the side surface of the cylinder head 2 on the exhaust side.

The cylinder head 2 has the intake valve ports 8a, 8.
A pair of intake valves 11a and 11b that open and close b, and an exhaust valve 14 that opens and closes the exhaust valve port 12 are each supported vertically and slidably.
a, 11b and the exhaust valve 14 are arranged on both sides of the central axis LL of the cylinder 4 so that their upper ends are inclined away from each other. The intake valve 1
1a, 11b and the exhaust valve 14, one valve drive camshaft 17 is located on the central axis LL of the cylinder 4.
bearing 18 formed thereon on the cylinder head 2
It is rotatably supported by a and 18b. The valve drive camshaft 17 is rotationally driven in conjunction with the crankshaft as usual. In addition, two intake valves 11a, 1
1b and the camshaft 17, and between the exhaust valve 14 and the camshaft 17, the cylinder head 2 has an intake side rocker arm shaft 19 and an exhaust side rocker arm shaft 20, each of which has a plurality of bearings 2 in parallel with the camshaft 17.
1a, 21b, 22a, and 22b, respectively. On the intake side rocker arm shaft 19,
Two intake side rocker arms 23a, 2 per cylinder
The outer ends of these rocker arms 23a, 23b are brought into contact with the upper ends of the intake valves 11a, 11b via adjusters 25, respectively, and the slipper surfaces 27 at the inner ends thereof are The intake side valve operating cams 29 on the camshaft 17 are in contact with each other. Also, the exhaust side Rotsuka arm shaft 2
0 has one exhaust side rocker arm 24 per cylinder.
is slidably supported on the shaft, and the rocker arm 2
The outer end of 4 is brought into contact with the upper end of the exhaust valve 14 via the adjuster 26, and the slipper surface 28 of the inner end
is in contact with the exhaust side valve operating cam 30 on the camshaft 17. And if the camshaft 17 is rotated,
Intake side and exhaust side rocker arms 23a, 23b
and 24 are rocker arm shafts 19 and 20, respectively.
The suction and exhaust valves 11a, 11b, 14
can be opened and closed in cooperation with valve springs 31 and 32.

As shown in FIG. 2, the two intake side rocker arms 23a, 23b and the one exhaust side rocker arm 24 are formed in exactly the same shape, and by specifying their arrangement, their compatibility can be confirmed. configured to obtain. That is, the two intake side rocker arms 23a and 23b each include a bearing cylinder part B rotatably supported on the rocker arm shaft 19, an inner arm part Ri extending from the bearing cylinder part B toward the valve operating camshaft 17 side, and an intake side rocker arm 23a, 23b. It is composed of an outer arm portion Ro extending toward the valves 11a and 11b, and the outer arm portion Ro is inclined in the axial direction of the rocker arm shaft 19 when viewed from a plane, and is formed in a flat U-shape as a whole. Also, one exhaust side rocker arm 24 has a bearing cylinder part B rotatably supported on the rocker arm shaft 20, an inner arm part Ri and an outer arm part Ro, just like the two intake side rocker arms 23a and 23b.
It consists of

Further, as shown in FIG. 2, the two intake-side rocker arms 23a and 23b are rotatably supported in parallel and adjacent to each other on the rocker arm shaft 19, biased to one side on the combustion chamber 6, and there is a space between them. A spacer 34 fitted to the rocker arm shaft 19 is interposed,
The rocker arm 23a near the center of the combustion chamber 6 is pressed by the spring 35 against the rocker arm 23b near the outside, and the axial spacing between them is maintained constant. The slipper surface 27 formed on the lower surface of each inner arm Ri is formed on the valve cams 29 and 2 on the valve camshaft 17.
9, and each outer arm portion Ro is connected to the intake valves 11a, 1 via the adjuster 25 as described above.
It is connected to the upper end of the stem portion of 1b. Further, one exhaust side rocker arm 24 is rotatably supported on the combustion chamber 6 toward the other side and adjacent to the intake side rocker arm 23a near the center, and its inner arm portion Ri
The slipper surface 28 formed on the lower surface of the valve cam 30 on the valve camshaft 17 is in contact with the outer arm.
Ro is connected to the upper end of the stem portion of the exhaust valve 14 via the adjuster 26 as described above. One exhaust side rocker arm 24 is disposed point-symmetrically to the intake side rocker arm 23b with respect to the central axis of the cylinder 4.

As described above, the two intake side rocker arms 23
Even if a, 23b and the exhaust side rocker arm 24 are formed exactly the same, by specifying their arrangement as described above, the mechanism can be operated smoothly and accurately without changing the configuration of the valve mechanism. Also, the valve train camshaft 17 and the rocker arm shaft 19, 2 can be
It is relatively rare for an uneven load to be applied to the load bearing parts such as the bearing part of the valve 0, and accordingly, uneven wear of these parts is less likely, and furthermore, maintenance of the valve mechanism is not hindered.

Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. In this second embodiment, two intake valves 111a and 111 are connected by one rocker arm shaft 119.
b and one exhaust valve 114,
The rocker arm shaft 119 is located directly above the valve drive camshaft 117, and the bearing 121a of the cylinder head 2,
121b. The two intake side rocker arms 123a and 123b are rotatably supported in parallel on the rocker arm shaft 119 adjacent to each other with the top of the combustion chamber 6 biased to one side, and one exhaust side rocker arm 124 is supported on the top of the combustion chamber 6 so as to be freely rotatable. It is rotatably supported on the rocker arm shaft 119 on the other side, adjacent to the intake side rocker arm 123a near the center. Two intake side rocker arms 123a, 12
3b, a spring 135 is also inserted between the intake side rocker arm 123a and the exhaust side rocker arm 124 near the center.
A spacer 134 is interposed between the three rocker arms 123a, 123b and 124.
are held on the rocker arm shaft 119 at a predetermined distance. And the intake side rocker arm 123b
, the exhaust side rocker arm 124 is the cylinder 4
are arranged point-symmetrically with respect to the central axis of.

Also in this second embodiment, the two intake-side rocker arms 123a, 123b and the exhaust-side rocker arm 124 can be formed identically, and the arrangement allows them to be mutually compatible.

As is clear from the above embodiments, according to the present invention, in the valve train of a cross-flow type three-valve internal combustion engine, one valve train camshaft is disposed approximately on the cylinder axis, and Two rocker arms for intake are placed adjacent to each other on the rocker arm axis and are arranged parallel to each other on the combustion chamber, and one rocker arm for exhaust is arranged adjacent to the rocker arm for intake near the center of the cylinder in the combustion chamber. The three rocker arms for intake and exhaust are arranged in the same way so that they are compatible, so that the three intake and exhaust
Exhaust valves can be shared, so one type can be used, and it also prevents incorrect assembly when assembling the engine, and it is easy to manage, resulting in a significant overall cost reduction.

In addition, by specifying the placement of the intake and exhaust valves as described above, it is possible to impose structural, functional, or maintenance constraints on the valve mechanism, or to apply partial unbalanced loads to the mechanism. This ensures smooth and light operation over a long period of time.

[Brief explanation of drawings]

1 to 3 show the first embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional view, FIG. 2 is a plan view, FIG. 3 is a bottom view taken along the line of FIG. 1, and FIG. 5 shows a second embodiment of the present invention, FIG. 4 is a longitudinal sectional view thereof, and FIG. 5 is a plan view thereof. 2...Cylinder head, 4...Cylinder, 5...
...Piston, 6...Combustion chamber, 7...Roof surface, 1
1a, 11b, 111a, 111b...intake valve,
14,114...Exhaust valve, 17,117...Valve train camshaft, 19,119...Rocker arm shaft, 20
...Rotsuka arm shaft, 23a, 23b, 123
a, 123b...Rotsuka arm, 24,124...
...Lotsuka arm, 29,129...Valve train cam, 3
0,130...Valve train cam.

Claims (1)

[Scope of utility model registration request] A combustion chamber 6 is provided on the inner surface of the cylinder head 2 and faces the upper surface of a piston 5 that is slidably fitted into the cylinder 4. On one side of the roof surface 7 of the combustion chamber 6, two intake valves 11a, 11b, 111a, 1
11b are arranged in parallel, and one exhaust valve 14, 114 is arranged on the other side, and one valve drive camshaft 17, 117 is rotatably supported on the combustion chamber 6. , 117 and the two intake valves 11.
a, 11b, 111a, 111b and one exhaust valve 14, 114 between the upper ends of the rocker arm shaft 1.
Suction/exhaust rocker arms 23a, 23b, 24, 123 slidably pivoted on 9, 20, 119
In a cross-flow type three-valve internal combustion engine valve train which is connected by a, 123b, and 124, the valve drive camshafts 17, 17 are aligned approximately with the axis L of the cylinder 4.
-L, and the rocker arm shaft 19,
Two rocker arms 2 for intake on 20,119
3a, 23b, 24, 123a, 123b, 12
4 are arranged adjacent to each other in parallel on the combustion chamber 6, and one rocker arm 24, 124 for exhaust is arranged adjacent to the rocker arm 23a, 123a for intake near the center of the cylinder 4 in the combustion chamber. The three rocker arms 23a, 23b, 24,
3 characterized in that all of 123a, 123b, and 124 are formed identically and are made compatible.
A valve train in a valve-type internal combustion engine.