JPS6318103A - Sohc type internal combustion engine - Google Patents

Abstract

PURPOSE:To make an exclusive plug accommodating barrel unnecessary to simplify an engine construction by forming a series of plug fitting holes over a range from abearing wall shaped in a body with a cylinder head so as to cross a cylinder head axis to a holder fixed to said bearing wall. CONSTITUTION:An intake and an exhaust valve 10, 11 are opened and closed by the rotation of a cam shaft 16 through an intake and an exhaust rocker arm 22, 23, and said cam shaft 16 is provided with a journal 19 corresponding to each cylinder. Said journal 19 is rotatably supported on a bearing formed between a pair of the joint surface of a bearing wall 26 formed in a body with a cylinder head 3 so as to cross a cylinder axis Y and of a holder 30 fixed to said bearing wall 26 with bolts 27-29. In addition to that, bosses supporting an intake and an exhaust rocker shaft 17, 18 are formed in a body with the holder 30, and a series of plug accommodating holes 38 communicating with plug fitting holes 37 opening toward the center of the ceiling of each combustion chamber 6 are provided over a range from said holder 30 to the bearing wall 26.

Description

Detailed Description of the Invention A4 Object of the Invention (1) Industrial Application Field The present invention relates to an SOHC internal combustion engine, particularly an intake valve and an exhaust port that respectively open and close an intake port and an exhaust port opening into a combustion chamber of a cylinder head. Exhaust valves are disposed on both sides of the axis of the cylinder, a camshaft is disposed between these intake and exhaust valves, and a camshaft is installed above the camshaft between the shaft and the intake and exhaust valves. A single suction and exhaust rocker shaft, which respectively supports the interlocking suction and exhaust rocker arms, is arranged parallel to the camshaft, and the spark plug is installed so that the electrode faces the center of the ceiling surface of the combustion chamber. This invention relates to an improvement in an internal combustion engine in which a cylinder head is provided with a plug mounting hole for use in the engine.

(2) Prior art This type of internal combustion engine is disclosed in Japanese Patent Application Laid-Open No. 166715/1983, and in the one disclosed therein, bearings are integrally formed in the cylinder head at corresponding positions between adjacent cylinders. A camshaft and intake/exhaust rocker shafts are supported on the wall, and a plug housing tube, which is manufactured separately from the bearing wall and houses the spark plug, is fixed to the cylinder head.

(3) Problems to be Solved by the Invention In the above-mentioned structure, a plug accommodating tube that exclusively accommodates the spark plug is essential, so the structure is complicated and assembly is troublesome, and the camshaft is attached to the bearing wall. Since it is inserted into the bearing hole from the side, the journal of the camshaft must be formed with a larger diameter than the intake and exhaust cams, which poses a problem of increasing the weight of the camshaft.

The present invention has been made in view of the above circumstances, and makes it possible to omit the plug housing tube, simplifying the structure, and
It is an object of the present invention to provide the SOHC type internal combustion engine in which the journal of the camshaft can be formed to have a smaller diameter than the intake and exhaust cams, and the weight of the camshaft can be reduced.

B0 Structure of the Invention (Means for Solving 11 Problems) In order to achieve the above object, a joint surface between a bearing wall integrally formed at the throat of the cylinder and a holder fixed thereto so as to cross the axis of the cylinder. The camshaft is supported by a bearing formed in the holder, and the suction and exhaust rocker shafts are supported in the holder, and the bearing wall and the holder are provided with a series of plug receiving holes communicating with the plug mounting holes and accommodating the spark plugs. It is characterized by having been established.

(2) Operation Since the camshaft is supported by a bearing formed between the joint surface of the bearing wall integrated with the cylinder head and the holder fixed to this, the bearing is of a split type, and the camshaft is supported by this bearing. Ba,
The journal of the camshaft can support this even if it has a smaller diameter than the intake and exhaust cam.

Since the spark plug is housed in the series of plug housing holes provided in the bearing wall and the holder, a dedicated plug housing cylinder can be omitted.

(3) Embodiment Hereinafter, an embodiment of the present invention will be explained with reference to the drawings. In FIGS. 1 to 3, a plurality of cylinders 1.
A throat 3 is connected to the cylinder via a gasket 4 on the upper surface of the cylinder block 2 having l... A piston 5 is slidably fitted into each cylinder 1, and a combustion chamber 6 is recessed in the bottom surface of the cylinder rad 3 facing the piston 5.

The ceiling surface 7 of each combustion chamber 6 has a plurality of cylinders 1°1...
It is formed into a mountain shape from two slopes Ta and 7b descending from the ridge line L (Fig. 3) extending in the arrangement direction of .
One end of a pair of intake ports 8.8 is on one slope 7a,
Also, one end of a pair of exhaust ports 9.9 is opened in the other slopes 7b, 7b in parallel along the ridgeline. The other end side of the pair of intake boats 8, 8 is the cylinder head 3
The pipes merge into one pipe inside the cylinder and open on one outer side of the cylinder 3, to which an intake manifold (not shown) is connected. Further, the other ends of the pair of exhaust ports 9, 9 merge into one in the cylinder head 3 and open on the other outer surface of the cylinder head 3, to which an exhaust manifold (not shown) is connected.

Each pair of intake boats 8, 8 and each pair of intake valves 10.10 and exhaust valves 11.10 for opening and closing the exhaust port 9°9.
11 is a valve guide 12 fitted into the cylinder head 3.
12 and 13.13, respectively.

In this case, the opposing intake and exhaust valves 10 and 11 are arranged in a V-shape on both sides of the axis Y of the cylinder 1 so that the valve heads are spaced apart from each other.

Valve springs 14 and 15 are attached to these intake and exhaust valves 10, 11, respectively, for biasing them in the valve closing direction.

Between the intake valve 10.10... group and the exhaust valve 11.11... group, a single camshaft 16 extending in the arrangement direction of the plurality of cylinders 1.1... is connected from the cylinder axis Y. Exhaust valve 1
It is arranged offset to the 1 side. Above this camshaft 16 is an intake rocker shaft 17 parallel to the shaft 16.
A force shaft 18 of the exhaust port 7, which is more deviated toward the intake valve 10 side and also parallel to the camshaft 16, is arranged so as to be deviated from the camshaft 16 toward the exhaust valve 11 side.

The camshaft 16 has one journal 19 corresponding to each cylinder 1 and a pair of exhaust cams 21 .
21, and a pair of intake cams 20.
20.

A pair of intake rocker arms 22.22 are swingably supported on the intake rocker shaft 17 in correspondence with each cylinder l, one end of which is connected to the intake cams 20, 20, and the other end is connected to an adjustment bolt 24.24. are respectively engaged with the heads of the intake valves 10.10 via the respective intake valves 10.10.

Further, a pair of exhaust rocker arms 23, 23 are pivotally supported on the exhaust rocker shaft 18 in correspondence with each cylinder l,
One end of these is engaged with the exhaust cam 21.21, and the other end is engaged with the head of the exhaust valve 11.11 via an adjustment pole (25.25).

The journal 19 includes a bearing wall 26 integrally formed with the cylinder head 3 so as to cross the cylinder axis Y, and a holder 3 fixed to the bearing wall 26 with three bolts 27, 28, and 29.
The rocker shaft 17.
18 is supported on bosses 32, 33 formed integrally with the holder 30. At this time, the exhaust rocker 618 in particular is prevented from rotating by the engagement of the semicircular notch 34 on its outer periphery with the outer periphery of the bolt 27.

The cylinder head 3 is provided with a plug mounting hole 37 as a screw hole that opens at the center of the ceiling surface 7 of each combustion chamber 6. The plug mounting hole 37 communicates with the intake port 7 and the intake valve. 10.10...A series of plug receiving holes 38 passing between the bearing wall 26 and the holder 30 are provided,
An ignition plug 39 is screwed into the plug mounting hole 37 through the plug receiving hole 38, and its electrode is placed in the center of the ceiling surface 7.

A sealing member 40 is interposed between the joint surfaces of the bearing wall 26 and the holder 30 so as to surround the plug receiving hole 38 .

The camshaft 16 also has a journal 19' at its end, as shown in FIG. Bearing 44 formed between the joint surfaces with 43
The holder 43 supports the ends of the intake and exhaust rocker shafts 17 and 18.

The intake rocker shaft 17 has adjacent intake rocker arms 22.
22, and a wave washer 45' that is interposed between the intake rocker arm 22 and the holder 43 at the outer position. The bullet is retained.

Further, the exhaust rocker shaft 18 has adjacent exhaust rocker arms 2.
3. A coil spring 46 interposed between the exhaust rocker arms 23 and a coil spring 46' interposed between the exhaust rocker arms 23 and the holders 43 at the outer positions are installed, so that each exhaust rocker arm 23 is attached to the adjacent holder 30. The bullet is retained.

As shown in FIG. 1, a head cover 47 that covers the upper end of the cylinder head 3 is joined via a seal member 48. This head cover 47 has a plug accommodation hole 38.
A plug insertion port 49 is provided which communicates with the head cover 47 and the bearing wall 26, and a seal member 50 is interposed between the opposing surfaces of the head cover 47 and the bearing wall 26 so as to surround the plug insertion port 49.

The plug housing hole 38 accommodates a plug camp 52 that is attached to the spark plug 39 in order to connect a high voltage cord 51 connected to an ignition coil (not shown) to the spark plug 39, and the upper end of the cap 52 is connected to the plug insertion opening 49. is hermetically fitted.

Next, the operation of this embodiment will be explained. During operation of the engine, the camshaft 16 is rotationally driven by the crankshaft via a timing transmission device (not shown). When the intake stroke begins in each cylinder 1, the intake cam 20.20 exerts a lifting action to move the intake rocker arm 22.22 to the intake valve 10.
Since the intake valve 10.10 is swung in the opening direction of the valve 10, the intake valve 10.10 is opened against the force of the valve spring 14.14, and the air-fuel mixture generated by an air-fuel mixture generating device such as a carburetor (not shown) flows into the intake boat. 8.8 into the cylinder 1.

When the intake cam 20.20 releases the intake rocker arm 22.22, the intake valve 10.10 closes under the force of the valve spring 14.14 and the engine moves into the compression stroke.

At the end of the compression stroke, the compressed gas in the combustion chamber 6 is ignited by a spark discharge from the spark plug 39, and the engine advances to the expansion stroke. At this time, since the electric scraper of the spark plug 39 is located at the center of the ceiling surface 7 of the combustion chamber 6, the flame propagation distance from the ignition point to the periphery of the combustion chamber 60 is approximately equal, and therefore the combustion time is minimized. , a good combustion condition that is advantageous for producing high output can be obtained.

Next, when the compression stroke is started, the exhaust cam 21.21 exerts a lifting action to move the exhaust Ronca arm 23.23 towards the exhaust valve 11.23. il in the valve opening direction, the exhaust valve 11
．． 11 opens against the force of valve springs 15, 15 to discharge exhaust gas from the combustion chamber 6 to exhaust ports 9, 9. Once the exhaust cam 21.21 releases the exhaust rocker arm 23.23, the exhaust valve 11.11 is moved by the valve spring 15. The valve closes with the force of Is.

In such an internal combustion engine, the journal 19,19' of the camshaft 16 is connected to the bearing wall 26, which is integral with the cylinder rod 3.
and bearings 31 and 44 formed between the joint surfaces of the end walls of the cylinder head 3 and the holders 30 and 43 fixed thereto.
These bearings 31.44 are of the split type, and the journals 19.19' are supported by the intake and exhaust cams 20.21.
Even if they have a smaller diameter, they can be easily supported by the bearings 31, 44.

Moreover, since the spark plug 39 is accommodated in the series of plug accommodation holes 38 provided in each bearing wall 26 and the holder 30, a dedicated plug accommodation cylinder is not required.

C4 Effects of the Invention As described above, according to the present invention, the camshaft is driven by the bearing formed between the joint surface of the bearing wall integrally molded on the cylinder head and the holder fixed to the bearing wall so as to cross the axis of the cylinder. At the same time, the holder supports the intake and exhaust rocker shafts, and the bearing wall and the holder are provided with a series of plug housing holes communicating with the plug mounting holes and housing the spark plugs, so that a dedicated plug housing cylinder is provided. This eliminates the need for the camshaft, which contributes to the N-element structure and improved assembly ease.
Although the journal is made smaller in diameter than the intake and exhaust cams, it is easy to assemble to the cylinder head and can contribute to reducing the weight of the camshaft.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 shows an SOH
A longitudinal side view of the C-type internal combustion engine. Figure 2 is a view taken along the ■-■ arrow in Figure 1 with the hend force bar removed. Figure 3 is a view taken along the mm--m line in Figure 1. 4, 5, and 6 are a side view, a top view, and a bottom view of the holder in the internal combustion engine. Y... Cylinder axis, 3... Cylinder head, 6... Combustion chamber, 7... Ceiling surface, 8... Intake port, 9... Exhaust port, 10
...Intake valve, 11...Exhaust valve, I6...Camshaft,
17...Intake rocker shaft, 18...Exhaust rocker shaft, 1
9... Journal, 20... Intake cam, 21...
Exhaust cam, 22...Intake port 7 arm, 23...Exhaust rocker arm, 26...Bearing wall, 30...Holder, 3I...Bearing time Applicant: Honda Motor Co., Ltd. Agent Patent attorney Ken Ochiai Figure 3 Figure 2

Claims (1)

[Claims] Intake valves and exhaust valves that respectively open and close the intake port and exhaust port that open into the combustion chamber of the cylinder head are arranged on both sides of the axis of the cylinder, and a single camshaft is arranged between these intake and exhaust valves. Above the camshaft, one suction and exhaust rocker shaft is arranged in parallel with the camshaft, each pivotally supporting a suction and exhaust rocker arm that interlocks between the shaft and the suction and exhaust valves, In an SOHC type internal combustion engine in which a plug mounting hole is provided in the cylinder head for mounting a spark plug so that the electrode faces the center of the ceiling surface of the combustion chamber, the plug is integrally molded in the cylinder head so as to cross the axis of the cylinder. The camshaft is supported by a bearing formed between the joint surface of the bearing wall and the holder fixed thereto, and the suction and exhaust rocker shafts are supported by the holder. An SOHC internal combustion engine characterized by having a series of plug receiving holes that communicate with each other to accommodate spark plugs.