JPH079167B2 - Valve mechanism of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention has one camshaft above a cylinder head,
The present invention relates to a valve operating mechanism of an internal combustion engine in which a spark plug is arranged so that an electrode faces the center of the top of a combustion chamber and each cylinder bore has four valves.

(Prior Art) A conventional spark ignition type internal combustion engine is a 4-valve type having a pair of intake valves and exhaust valves for each cylinder bore, and one camshaft and intake / exhaust between a pair of intake / exhaust valves. SO with two rocker arms for
There is an HC type (Japanese Patent Laid-Open No. 60-166715) in which the electrode of the spark plug is disposed so as to face the central top of the combustion chamber. In addition to reducing the width and height of the cylinder head, the combustion fire in the combustion chamber is spread quickly and evenly from the center to the peripheral edge of the combustion chamber to suppress knocking and improve combustion efficiency. .

(Problems to be Solved by the Invention) However, in the above-mentioned conventional valve operating mechanism of the internal combustion engine,
Since the plug insertion cylinder that inserts and holds the spark plug and the support member (cam holder) that supports the cam shaft were configured as separate members, there was a problem that the number of parts increased and the number of assembly work steps increased. . Further, in the prior art, the sealing of the mounting portion between the plug insertion cylinder and the cylinder head and the head cover is performed by inserting a pipe into the plug hole and inserting an O-ring between the pipe and the pipe. There is a problem that it is difficult to reliably seal between them.

Therefore, according to the present invention, the cam holder is integrally formed with the plug insertion cylinder to reduce the number of parts and the workability of assembling, and an O-ring is provided on the mounting surface of the plug insertion cylinder and the cylinder head and the cylinder head cover. It is an object of the present invention to provide a valve operating mechanism of an internal combustion engine that can reliably seal between them by interposing them.

(Means for Solving Problems and Actions Thereof) According to the valve mechanism of the present invention, one camshaft and two rocker arm shafts are provided along the cylinder bore row above the cylinder head on the cylinder bore in which a plurality of cylinder bores are arranged. Plugs for inserting spark plugs, which are arranged parallel to each other, are provided at positions above both sides of each cylinder bore to support the cam shaft, and are inclined upward toward the center top of the combustion chamber and reach between the cam holders on both sides of each cylinder bore. The hole is provided in the cylinder head and the plug insertion cylinder fixed to the upper surface of the cylinder head, and the cam holders on both upper sides of the cylinder bores are integrally formed with the plug insertion cylinder.

Therefore, since the cam holder is formed integrally with the plug insertion cylinder, the number of parts can be reduced and the assembling workability can be improved.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of an internal combustion engine showing a valve operating mechanism, FIG. 2 is a plan view of an essential part thereof, (1) is a cylinder block,
(2) is the cylinder bore, (3) is the cylinder head,
(4) shows a cylinder head cover. The cylinder block (1) is provided with four cylinder bores (2) along its longitudinal direction, the cylinder head (3) is fixed on the cylinder block (1), and the combustion chamber (5) is attached to the cylinder head (3). Is provided with an intake passage (right side in the figure) (6) and an exhaust passage (left side in the figure) (7). Further, the cylinder head (3) has four cylinder bores (2) for each cylinder bore (2).
One valve hole, ie a pair of intake valve holes (6a) and two
The cylinder head (3) has a pair of intake valve holes (7a), so that a pair of intake valves (9) and a pair of exhaust valves (10) are arranged in each cylinder bore. It is a 4-valve type installed. These valves (9, 10) are provided with a set of intake valves (9) along the longitudinal direction on the intake side of the cylinder head (3) for each cylinder bore (2), and 3)
A set of exhaust valves (10) along its length on the exhaust side of
The intake valve (9) and the exhaust valve (10) are inclined with each other so as to be separated from each other above the cylinder head (3). The intake valve (9) and the exhaust valve (10) are supported by valve guides (11) and (12) so as to be movable in the axial direction, and a spring retainer (13, 14) fixed to each base end side. The valve seats (15, 16) are urged in the closing direction of the valves (9, 10) by valve springs (17, 18) interposed between the seats (15, 16).

A camshaft (20) is arranged above the cylinder bore row and above the cylinder head (3), and two rocker arm shafts (21) are arranged on both sides above the camshaft (20). And (22) are arranged, and the cam shaft (20) and the rocker arm shafts (21, 22) are arranged in parallel with each other. The camshaft (20) is provided with cams (20a ..., 20b ...) that drive a pair of rocker arms (23, ..., 24, ...) on the intake and exhaust sides for each cylinder bore (2). The intake side cams (20a, 20a) are located on both sides, and the exhaust side cams (2a, 20a) are located between them.
0b, 20b) are provided. The exhaust side rocker arms (24) and (24) are arranged between the intake side rocker arms (23) and (23) so as to correspond to the cam arrangement.
The intake-side rocker arm (23, 23) is supported by the rocker arm shaft (21), and the exhaust-side rocker arm (24, 24) is supported by the rocker arm shaft (22). Further adjacent rocker arms (24) and (24), or (23,23)
A wave washer (40) is interposed between the bearings of the cam holder (25) and the cam holder (25), thereby biasing the rocker arm bearings toward the rocker arm shaft support.

The cam shaft (20) is arranged so as to be offset from the center of each cylinder bore (2) toward the exhaust side (left side in the drawing), and is supported by the cam holder (25) at both ends and a plurality of intermediate positions. ing. As shown in FIG. 2, the cam holder (25) is located above both sides of each cylinder bore (2), that is, above each cylinder bore (2), and includes the rocker arm (2).
3,23,24,24) on both sides of the cylinder head (3). These cam holders (25) include a lower bearing portion (not shown) protrudingly provided on the upper surface of the cylinder block (3), and an upper bearing portion (27) fixed to the lower bearing portion by bolts (26, 36) from above. The rocker arm shafts (21) and (22) supporting portions (27A) on the intake and exhaust sides, which will be described later, are provided on both ends of the upper bearing portion (27) as shown in FIG. 3 (b).
And (27B) are integrated.

Further, as shown in FIG. 1, the cylinder head (3) is provided with a spark plug (29). This plug (2
9) is inserted into the plug hole (30). Plug hole (3
0) is fixed to the cylinder head (3) and the upper surface of this cylinder head (3) so that one end side faces the central top of the combustion chamber (5) and the other end side inclines upward on the side opposite to the camshaft (20). It is formed over the plug insertion tube (31). In other words, the plug hole (30) is provided so as to be positioned along the intake valve (9) on the other end side so as to be located between the pair of intake valves (9). The (31) is also formed so as to extend obliquely upward and is fixed onto the cylinder head (3) by a bolt (39) described later. A spark plug (29) is screwed on the tip side of the plug hole (30) with its electrode facing the combustion chamber (5). The spark plug (29) has a base of the plug hole (30). An ignition cable (47) passing through a cap (46) attached to the end side is connected. Therefore, since the electrode can face the center of the top of the combustion chamber (5), knocking is reduced.

Further, the upper and lower surfaces of the plug insertion cylinder (31) are formed on the horizontal plane similarly to the joint surface of the cylinder head (3), while the plug insertion portion (3) provided on the cylinder head cover (4) is formed.
The lower surface of 2) is also formed to be horizontal. An annular groove (3a) is formed on the joint surface of the cylinder head (3), and an annular groove (32a) is formed on the lower surface of the plug insertion portion (32). The insertion cylinder (31) is the plug insertion portion. (32) or the cylinder head (3), each annular groove (32a) or (3
They are joined via O-rings (33a) or (33b) which are mounted in a). Therefore, it is possible to reliably perform sealing on these mounting surfaces.

Of the rocker arm shafts (21) and (22), the rocker arm shaft (22) on the exhaust side has an oil passage (22
It is formed in a single hollow tube having a) and is supported by a support portion (27B) integral with the cam holder (25) at a plurality of points and supports the rocker arm (24, 24) on the exhaust side. On the other hand, the rocker arm shaft (21) on the intake side has a plurality of short shafts (21A) divided in the axial direction as shown in FIG. 3 (a).
...). Each of these minor axes (21A ...)
As shown in FIG. 2, the set of intake valves (9)-
To avoid the plug hole (30) arranged between (9),
It is arranged at a predetermined interval between adjacent end portions.

Each of the short shafts (21A ...) Is formed as a hollow tube having an oil passage (21a) therein, and both ends of each oil passage (21a) are sealed by a seal member (41).

In addition, each short shaft (21A) has an intermediate part for each cam holder (2A).
5) Bolts (36) on the support part (27A) formed integrally with
Are fixed to the upper part of the rocker arm (23,2
We support two of each 3).

Reference numeral 34 in the figure denotes a stopper ring fixed to the end of the short shaft (21A) so as to be locked to the rocker arm (23 ...).

Further, among the cam holders (25), the cam holders (25) provided on one end side of the cylinder head (3) have plugs in the vicinity thereof via one rib (37a) extending from the end thereof. It is formed integrally with the insertion tube (31),
Each of the cam holders (31) between the cylinder bores in the cylinder bore row is provided with two ribs (37a) and (37b) extending from the ends thereof to two adjacent plug insertion cylinders (31, 31) in the vicinity thereof. They are sequentially formed integrally. The other ends of the adjacent cam holders (25 ...) Are connected by ribs (38 ...) As shown in FIG. 3 (b). That is, both the cam holders (25 ...), the support portions (27A ..., 27B ...) of both of the rocker arm shafts (21, 22), and the plug insertion tube (31
…) Are all integrated, reducing the number of parts. The cam holders (31 ...) And the plug insertion cylinders (31 ...) of this integral structure are provided with bolts (26 ..., 36 ...) for mounting the cam holders (26) and mounting holes (31a) for the plug insertion cylinders (31 ... ) Is secured to the cylinder head (3) by a bolt (39). Therefore, the number of assembly work steps is reduced.

Further, in this embodiment, the cam shaft (20) and the rocker arm shafts (21, 22) are provided with a lubrication system.
In this lubrication system, an oil passage (4 that opens from the main gallery (not shown) to the lower bearing that supports the camshaft is used.
2) is provided in the cylinder head (3), and the upper bearing portion (27) of the cam holder (25) has an oil passage (44a) communicating with the oil passage (42) and an oil passage (44a) sequentially communicating therewith. 44
b), an oil sump (44c) and an oil passage (44d) are provided. The oil passage (44a) opens to the support surface (27b) of the support portion (27B) of the one rocker arm shaft (22), and the oil passage (44d) of the support portion (27A) of the other rocker arm shaft (21). Open to the support surface (27a) and
c) is formed on the camshaft support surface (27c) of the upper bearing portion (27) to lubricate the camshaft bearing portion. The oil passage (44a) communicates with the oil passage (22a) inside the rocker arm shaft via a communication hole (22b) formed in the rocker arm shaft (22). The rocker arm shaft (22) is provided with communication holes (2) communicating with the oil passage (22a) at both sides supporting the rocker arms (24, 24).
2c, 22c) are provided respectively to lubricate the sliding contact surface with the rocker arms (24, 24). On the other hand, the oil passage (44d) is provided with a communication hole (21A) formed in each short shaft (21A ...).
It communicates with the oil passage (21a) inside the short shaft via b).
Then, communication holes (21c, 21c) communicating with the oil passages (21a) are respectively provided at positions on both sides which support the rocker arms (23, 23) of the respective short shafts (21A ...), and thereby, the rocker arms (23, 23). 23) Lubrication of the sliding contact surface with. Therefore, each sliding portion can be reliably lubricated with a simple structure.

In the above embodiment, each cam holder (25) between the cylinder bores is integrally formed with the two plug insertion cylinders (31) in the vicinity thereof, and each cam holder (25 ...) And each plug insertion cylinder (31 ...). Although the case where all and are integrally formed is described, the structure shown in FIG. 4 or FIG. 5 may be adopted.

That is, in FIG. 4, one cam holder (25)
And two plug insertion cylinders in the vicinity of this are made into one set, and these are integrally formed by ribs (37a) and (37b). Further, in FIG. 5, one cam holder (25) and one plug insertion cylinder (31) are set as one set, and these are integrally formed by the rib (37a).
Therefore, the integral structure of the cam holder and the plug insertion cylinder as shown in FIGS. 4 and 5 can reduce the number of parts and the number of assembling steps.

(Effect of the Invention) According to the present invention as described above, since the cam holders on both upper sides of each cylinder bore are integrally formed with the plug insertion cylinder, the number of parts can be reduced and the number of assembling steps can be reduced. Becomes

[Brief description of drawings]

1 to 3 (b) show an embodiment of a valve mechanism according to the present invention. FIG. 1 is a cross sectional view thereof, FIG. 2 is a plan view of an upper portion of a cylinder head, and FIG. 3 (a). ) Is a schematic perspective view for explaining the lubrication system, FIG. 3B is a perspective view of a main part showing a cam holder and a plug insertion cylinder which are integrally formed,
FIG. 5 is a plan view of relevant parts showing a cam holder and a plug insertion cylinder according to another embodiment, and FIG. 5 is a plan view of relevant parts showing a cam holder and a plug insertion cylinder according to another embodiment. In the drawing, 2 ... Cylinder bore, 3 ... Cylinder head, 5 ... Combustion chamber, 20 ... Camshaft, 21,22 ... Rocker arm shaft, 25 ... Cam holder, 29 ... Spark plug, 30
...... Plug hole, 31 ...... Plug insertion tube, 37a, 37b ...... Rib.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F02P 13/00 301 B

Claims (4)

[Claims] 1. A camshaft and a plurality of rocker arm shafts are arranged parallel to each other along a row of cylinder bores above a cylinder head on a cylinder bore in which a plurality of cylinder bores are arranged to support the camshafts. A cam holder is provided above both sides of each cylinder bore, and a plug hole for inserting a spark plug that faces the center top of the combustion chamber and inclines upward is inserted between the cam holders on both sides of each cylinder bore and is fixed to the cylinder head and the top surface of this cylinder head. In the valve operating mechanism of the internal combustion engine provided over the plug inserting cylinder, the cam holders on both sides of each cylinder bore are integrally formed with the plug inserting cylinder. 2. A valve operating mechanism for an internal combustion engine according to claim 1, wherein one cam holder and one plug insertion cylinder above both sides of each cylinder bore are set as a set, and these are integrally formed. 3. A valve operating engine for an internal combustion engine according to claim 1, wherein one cam holder above both sides of each cylinder bore and two plug insertion cylinders in the vicinity thereof are formed as a set, and these are integrally formed. . 4. A valve mechanism for an internal combustion engine according to claim 1, wherein the cam holder has a support portion for a rocker arm shaft.