JPH0588363B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Application Field The present invention provides a pair of engine valves of the same type per cylinder,
A single camshaft, a pair of rocker arms swingably supported on rocker arm shafts to interlock and connect these engine valves and camshafts, and a spark plug placed facing the center of the ceiling of the combustion chamber. The present invention relates to a multi-cylinder SOHC type internal combustion engine including a plug tube disposed between the rocker arms for insertion.

(2) Prior art Such an internal combustion engine is known, for example, from Utility Model Application No. 167112
It is known from the publication No.

(3) Problems to be Solved by the Invention However, in the above conventional system, the rocker arm shaft is arranged between the camshaft and the plug cylinder at a distance from the plug cylinder, and the rocker arm shaft is fixed with a bolt. ing. For this reason, it is necessary to provide a space between the plug cylinder and the rocker arm shaft, which has been an obstacle to making the engine more compact.

The present invention has been made in view of the above circumstances, and is a multi-cylinder multi-cylinder in which the plug cylinder and the rocker arm shaft are brought close to each other to achieve compactness, and the rotation of the rocker arm shaft is prevented by the plug cylinder.
The purpose is to provide a SOHC type internal combustion engine.

B. Structure of the Invention (1) Means for Solving the Problems According to the first feature of the present invention, the rocker arm shaft holder that is disposed between both rocker arms and supports the rocker arm shaft, and the rocker arm shaft are provided with a plug. At least a portion of the tube is inserted.

According to a second feature of the present invention, the cam holder is arranged along the plug tube in a direction perpendicular to the axis of the camshaft in order to rotatably support the camshaft in cooperation with a holder portion provided on the cylinder head. A rocker arm shaft holder that supports the rocker arm shaft is disposed between the rocker arms and the rocker arm shaft, with at least a portion of the rocker arm shaft holder interposed between the cam holder and the plug cylinder, and the rocker arm shaft holder and the rocker arm shaft include: At least a portion of the plug tube is inserted.

According to the third feature of the present invention, the cam holder is arranged in the holder portion along with the plug tube in a direction orthogonal to the axis of the camshaft in order to rotatably support the camshaft in cooperation with the holder portion provided in the cylinder head. A rocker arm shaft holder supporting the rocker arm shaft is disposed between the two rocker arms, with at least a portion of the rocker arm shaft holder interposed between the cam holder and the plug cylinder, and the rocker arm shaft holder and the rocker arm shaft include: Each of the notches is provided with a notch into which a part of the plug cylinder is inserted, and both of the notches are formed so as to be connected to each other while the rocker arm shaft is supported by the rocker arm shaft holder.

(2) Effect According to the configuration of the first feature, at least a portion of the plug tube is fitted into the rocker arm shaft holder and the rocker arm shaft, so that the rocker arm shaft can be brought close to the plug tube, and the plug shaft can be moved closer to the rocker arm shaft. can prevent the rocker arm shaft from rotating.

Further, according to the configuration of the second feature, the first feature
Not only can the effects of the above characteristics be obtained, but also the space created by the arrangement of the plug cylinder can be used effectively.

According to the configuration of the third feature, not only the effect of the second feature can be obtained, but also the two notches are connected to each other, so that the rocker arm shaft can be easily positioned with respect to the rocker arm shaft holder.

(3) Embodiment An embodiment in which the present invention is applied to a multi-cylinder SOHC four-valve internal combustion engine will be explained below with reference to the drawings. First, in FIGS. 1, 2 and 3, the engine body E The cylinder block 1 includes a cylinder block 1 and a cylinder head 2 which is polymerized and bonded to the upper part of the cylinder block 1 via a gasket 3, and a plurality of cylinders 4 provided in the cylinder block 1 have pistons 5 slidably attached thereto. They are fitted together.
A combustion chamber 6 is defined for each cylinder by the cylinder block 1, cylinder head 2, and piston 5, and the ceiling surface of the combustion chamber 6 is formed in the shape of a roof that slopes toward each other.

Two intake valve ports 7a and 7b with the same diameter are opened in parallel on one side of the ceiling surface of the combustion chamber 6, and two exhaust valve ports with a slightly smaller diameter than the intake valve ports 7a and 7b are opened on the other side of the ceiling surface. The valve ports 8a, 8b are the intake valve ports 7a, 7.
The openings are opened in parallel and opposite to b.

Intake ports 9a, 9b communicating with the two intake valve ports 7a, 7b are bored in the cylinder head 2;
The fuel pumps are collected into one line within the tank and connected to a fuel supply device, such as a carburetor, via an intake manifold (not shown). Further, exhaust ports 10a, 10b communicating with the two exhaust valve ports 8a, 8b are bored in the cylinder head 2, and these exhaust ports 10a, 10b
are collected into one line within the cylinder head 2 and connected to the exhaust system via an exhaust manifold (not shown).

The cylinder head 2 includes a pair of intake valves 11 which are the same type of engine valves that open and close intake valve ports 7a and 7b.
a, 11b, and a pair of exhaust valves 12a, 12b that open and close the exhaust valve ports 8a, 8b are supported so as to be slidable up and down, respectively. Moreover, the intake valves 11a, 11
b and the exhaust valves 12a, 12b are arranged on both sides of the central axis 13 of the cylinder 4 so that their upper ends are inclined away from each other.

Both intake valves 11a, 11b and both exhaust valves 12
A single camshaft 14 is rotatably disposed above the combustion chamber 6 and in the vicinity of the central axis 13 between the camshafts a and 12b. An intake-side rocker arm shaft 15 parallel to the camshaft 14 is fixedly disposed above the camshaft 14 between the camshaft 14 and the two intake valves 11a and 11b, and is connected to the camshaft 14 and the two exhaust valves. 12a and 12b, an exhaust side rocker arm shaft 16 parallel to the camshaft 14 is fixedly disposed above the camshaft 14.

Two intake side rocker arms 17a and 17b per cylinder are swingably supported on the intake side rocker arm shaft 15, and these rocker arms 1
The outer ends of 7a and 17b are brought into contact with the upper ends of intake valves 11a and 11b via adjusters 19, respectively,
A slipper surface 20 provided at the inner end of each rocker arm 17a, 17b is in sliding contact with an intake side valve operating cam 21 of the camshaft 14, respectively. Two exhaust side rocker arms 18a and 18b per cylinder are swingably supported on the exhaust side rocker arm shaft 16.
The outer ends of the rocker arms a and 18b are brought into contact with the upper ends of the exhaust valves 12a and 12b via adjusters 22, respectively, and the slipper surfaces 23 provided at the inner ends of the rocker arms 18a and 18b are connected to the exhaust side valves of the camshaft 14. It is in sliding contact with the cam 24. Therefore, as the camshaft 14 rotates, the intake side and exhaust side rocker arms 17a, 17b; 18a, 18b swing around the rocker arm shafts 15, 16, respectively, and the intake and exhaust valves 11a, 11b; 12a, 12b
can be opened and closed in cooperation with valve springs 25 and 26.

Referring to FIGS. 4 and 5 together, the camshaft 14 includes a holder portion 27 that is integrally provided at the upper part of the cylinder head 2, and a cam holder 28 that is connected to the holder portion 27 with bolts 29 and 30. The holder portion 27 is rotatably supported between the intake valves 11a and 11b and between the exhaust valves 12a and 12.
The camshaft 14 is raised upward at the center between
The cylinder head 2 extends in a direction perpendicular to the cylinder head 2 and is integrally provided at the upper part of the cylinder head 2. A semicircularly recessed support surface 31 is provided on the upper surface of the holder portion 27.
A semicircular support surface 32 provided on the lower surface of the cam holder 28 corresponding to the support surface 31;
1, the camshaft 14 is rotatably supported.

An insertion hole 33 is formed in the cam holder 28, and the exhaust side rocker arm shaft 16 is inserted into the insertion hole 33. Furthermore, a holder 34 is attached to the end of the cylinder head 2 along the axial direction of the camshaft 14, and the end of the exhaust side rocker arm shaft 16 is supported by the holder 34. Further, the bolt 30 is arranged to pass through a part of the exhaust side rocker arm 16 and connect the holder portion 27 and the cam holder 28 to each other, and the exhaust side rocker arm shaft 16 is prevented from rotating by the bolt 30. There is.

The exhaust side rocker arms 18a and 18b are attached to the cam holder 2 along the axis of the exhaust side rocker arm shaft 16.
The holder 34 is arranged adjacent to both sides of the holder 34.
A coil spring 35 surrounding the exhaust rocker arm shaft 16 is interposed between the exhaust rocker arm 18b and between the exhaust rocker arms 18b and 18a. These coil springs 35 elastically bias each exhaust-side rocker arm 18a, 18b toward the cam holder 28, thereby fixing the axial position of each rocker arm 18a, 18b.

The cam holder 28 has an intake side rocker arm shaft 1.
A rocker arm shaft holder 37 for supporting the rocker arm shaft 5 is integrally provided, and the rocker arm shaft 15 on the intake side is inserted through an insertion hole 36 formed in the rocker arm shaft holder 37.
The end portion of is supported by a holder 34. The rocker arm shaft holder 37 is formed thicker in the axial direction than the portion of the cam holder 28 that supports the camshaft 14, and the rocker arms 17a, 17b on the intake side are further away from the cam holder 28 than the rocker arms 17a, 17b on the exhaust side. It is supported by the intake side rocker arm shaft 15 so as to be in sliding contact with the camshaft 14 at the separated position.

In order to prevent the axial movement of both intake side rocker arms 17a and 17b, the intake side rocker arms 17
A web washer 38 is provided between the locker arms 17a and holder 34 and between both intake side rocker arms 17a and 17b.
are interposed respectively.

The holder portion 27 is provided with an insertion hole 39 extending obliquely from a position below the rocker arm shaft holder 37 toward the center of the ceiling surface of the combustion chamber 6.
A screw hole 40 communicating with the combustion chamber 6 is provided at the tip of this insertion hole 39 . A spark plug P is inserted into the insertion hole 39, and the spark plug P is screwed into the screw hole 40 with its tip facing the center of the ceiling surface of the combustion chamber 6.

A plug cylinder 41 is attached to the upper surface of the holder portion 27 via a sealing member 42, and is aligned with the cam holder 28 in a direction perpendicular to the axis of the camshaft 14 and coaxially connected to the insertion hole 39. Furthermore, a head cover 44 that covers the valve train and is coupled to the cylinder head 2 via a seal member 43 is integrally provided with a pressing portion 46 that contacts the upper end of the plug cylinder 41 via a seal member 45. .

The cam holder 28 corresponds to this plug cylinder 41.
The rocker arm shaft holder 37 has a plug tube 41.
A semicircular notch 4 for inserting and accommodating a part of the
7 is provided, and the intake side rocker arm shaft 15
A notch 48 for fitting and accommodating a portion of the plug cylinder 41 is also provided in a portion corresponding to the rocker arm shaft holder 37. Moreover, both notches 47, 4
When the rocker arm shaft holder 37 supports the rocker arm shaft 15 on the intake side, the rocker arm shafts 8 are formed so as to be connected to each other at the same position in the axial direction to form a semicircular shape.

A hole 49 connected to the plug tube 41 is bored in the pressing portion 46 of the head cover 44.
9 is closed by a cap 51 provided on a cord 50 connected to the spark plug P so as to be openable and closable.

Next, the operation of this embodiment will be explained. When the camshaft 14 is rotationally driven in accordance with the operation of the engine, the intake side and exhaust side rocker arms 17a, 1
7b; 18a and 18b swing around the intake side and exhaust side rocker arm shafts 15 and 16, and the valve spring 2
5, 26, the two intake valves 11a, 11
b and the two exhaust valves 12a, 12b are opened and closed at predetermined timing. Moreover, since the spark plug P is arranged facing the center of the ceiling surface of the combustion chamber 6, the flame propagation distance from the ignition point to each peripheral edge of the combustion chamber 6 is approximately equal, and therefore the combustion time is shortened to the minimum. High output is demonstrated.

At this time, since the plug cylinder 41 is fitted into the notch 48 of the intake side rocker arm shaft 15,
Rotation is prevented, and the exhaust side rocker arm shaft 1
6 is prevented from rotating by a bolt 30.

In such a SOHC type internal combustion engine, the camshaft 14
A rocker arm shaft holder 37 is disposed between the cam holder 28, which is coupled to the holder portion 27 in line with the plug cylinder 41 in a direction perpendicular to the axis of the plug cylinder 41, and the plug cylinder 41.
Since at least a part of the plug cylinder 4
By effectively arranging the rocker arm shaft holder 37 and the cam holder 28 in the space created by the arrangement of the camshaft 14, it is possible to downsize the engine in the direction along the axis of the camshaft 14.

Also, the plug tube 41 is attached to the rocker arm shaft holder 37.
By fitting a part of the rocker arm shaft holder 37, the rocker arm shaft holder 37 can be positioned by the plug tube 41 when the rocker arm shaft holder 37 is assembled, and the assembly work can be facilitated.

Further, the intake side rocker arm shaft 15 is provided with a notch 48 into which a part of the plug tube 41 is inserted, so that the plug tube 41 can prevent angular displacement of the rocker arm shaft 15 around the axis. Shaft holder 37 or cam holder 28
The intake side rocker arm shaft 15 can be fixed simply by attaching it to the holder part 27, which simplifies the assembly work.
The plug cylinder 41 can be placed closer to the plug cylinder 41, which contributes to making the engine more compact. Moreover, when the intake side rocker arm shaft 15 is supported by the rocker arm shaft holder 37, by aligning the notches 47 and 48, the intake side rocker arm shaft 15 can be supported relative to the rocker arm shaft holder 37.
It becomes easy to determine the mounting position of the holder, and the assembly work becomes easier.

As another embodiment of the present invention, the intake side rocker arm shaft 15 is divided in the axial direction at a portion corresponding to the rocker arm shaft holder 37, and a notch for fitting and accommodating the plug cylinder 41 is provided at each divided end. It may also be provided.

C. Effects of the Invention As described above, according to the first feature of the present invention, at least a portion of the plug tube is attached to the rocker arm shaft holder that is disposed between both rocker arms and supports the rocker arm shaft, and the rocker arm shaft. Since it is fitted, the plug tube and rocker arm shaft can be placed close together, contributing to the downsizing of the engine, and the plug tube can prevent rotation of the rocker arm shaft, making assembly work easier. be able to.

According to a second feature of the present invention, the cam holder is arranged along the plug tube in a direction perpendicular to the axis of the camshaft in order to rotatably support the camshaft in cooperation with a holder portion provided on the cylinder head. A rocker arm shaft holder that supports the rocker arm shaft is disposed between the rocker arms and the rocker arm shaft, with at least a portion of the rocker arm shaft holder interposed between the cam holder and the plug cylinder, and the rocker arm shaft holder and the rocker arm shaft include: Since at least a portion of the plug tube is inserted, in addition to the effect of the first feature described above, the space created by the arrangement of the plug tube can be effectively utilized to make the engine more compact.

Furthermore, according to a third feature of the present invention, the cam holder is arranged along the plug tube in a direction perpendicular to the axis of the camshaft in order to rotatably support the camshaft in cooperation with a holder section provided on the cylinder head. A rocker arm shaft holder that supports the rocker arm shaft is disposed between the rocker arm shaft and the rocker arm shaft, with at least a portion of the rocker arm shaft holder interposed between the cam holder and the plug cylinder. , a notch for fitting a part of the plug cylinder is provided, and both the notches are formed so as to be connected to each other while the rocker arm shaft is supported by the rocker arm shaft holder. In addition to the effects of the features, positioning of the rocker arm shaft when assembling the rocker arm shaft to the rocker arm shaft holder is facilitated.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a vertical sectional side view, Fig. 2 is a view taken along the line - in Fig. 1 with the head cover removed, and Fig. 3 is a view taken along the - line in Fig. 1. A perspective view, FIG. 4 is a sectional view taken along the - line in FIG. 1,
FIG. 5 is an exploded perspective view of the holder portion, cam holder, and rocker arm shaft. 2... Cylinder head, 6... Combustion chamber, 11
a, 11b... Intake valve as engine valve, 14...
Cam shaft, 15...Rotsuka arm shaft, 17a, 17
b...Lotsuka arm, 27...Holder part, 28...
...Cam holder, 37...Rotsuka arm shaft holder,
41...Plug tube, 47, 48...Notch, P
...Spark plug.

Claims (1)

[Claims] 1. A pair of similar engine valves 11a, 11 per cylinder.
b, a single camshaft 14, and these engine valves 11
A pair of locker arms 17a, 17b are swingably supported on a locker arm shaft 15 to interlock and connect the locker arms 17a, 11b and the camshaft 14, and a spark plug P is arranged facing the center of the ceiling surface of the combustion chamber 6. A multi-cylinder SOHC comprising a plug cylinder 41 disposed between the rocker arms 17a and 17b for insertion.
In the type internal combustion engine, both rocker arms 17
A multi-cylinder SOHC type internal combustion engine characterized in that at least a part of a plug cylinder 41 is fitted into a rocker arm shaft holder 37 disposed between a and 17b and supporting a rocker arm shaft 15, and a rocker arm shaft 15. . 2 A pair of similar engine valves 11a, 11 per cylinder
b, a single camshaft 14, and these engine valves 11
A pair of locker arms 17a, 17b are swingably supported on a locker arm shaft 15 to interlock and connect the locker arms 17a, 11b and the camshaft 14, and a spark plug P is arranged facing the center of the ceiling surface of the combustion chamber 6. A multi-cylinder SOHC comprising a plug cylinder 41 disposed between the rocker arms 17a and 17b for insertion.
In this type of internal combustion engine, a cam holder 28 is arranged in a holder section along with the plug tube 41 in a direction perpendicular to the axis of the camshaft 14 in order to rotatably support the camshaft 14 in cooperation with a holder section 27 provided on the cylinder head 2. 27, and both rocker arms 17a,
A rocker arm shaft holder 37 that supports the rocker arm shaft 15 is disposed between the rocker arm shaft holder 37 and the rocker arm shaft 17b, with at least a portion of the rocker arm shaft holder 37 intervening between the cam holder 28 and the plug tube 41. , plug tube 4
A multi-cylinder SOHC type internal combustion engine, characterized in that at least a part of the engine is inserted into the engine. 3 A pair of similar engine valves 11a, 11 per cylinder
b, a single camshaft 14, and these engine valves 11
A pair of locker arms 17a, 17b are swingably supported on a locker arm shaft 15 to interlock and connect the locker arms 17a, 11b and the camshaft 14, and a spark plug P is arranged facing the center of the ceiling surface of the combustion chamber 6. A multi-cylinder SOHC comprising a plug cylinder 41 disposed between the rocker arms 17a and 17b for insertion.
In this type of internal combustion engine, a cam holder 28 is arranged in a holder section along with the plug tube 41 in a direction perpendicular to the axis of the camshaft 14 in order to rotatably support the camshaft 14 in cooperation with a holder section 27 provided on the cylinder head 2. 27, and both rocker arms 17a,
A rocker arm shaft holder 37 that supports the rocker arm shaft 15 is disposed between the rocker arm shaft holder 3 and the rocker arm shaft holder 37 with at least a portion thereof interposed between the cam holder 28 and the plug tube 41.
7 and the rocker arm shaft 15 are equipped with a plug tube 41.
Notches 47 and 48 are respectively provided for fitting a part of the rocker arm shaft 15 into the rocker arm shaft holder 37. Features a multi-cylinder SOHC internal combustion engine.