JPH08284745A - Structure of locker cover for ohc-type internal combustion engine - Google Patents

Abstract

PURPOSE: To provide the structure of a internal combustion engine locker cover which provides a locker case with a cam cap function and a function for leading out a lubricating oil in a cylinder head outward as an increase in weight and the enlargement of an external form are restrained. CONSTITUTION: The circumferential wall part 11a of a locker case 11 opposite to the end of a cam cap 18 of a frame-shaped locker case 11 located above the cylinder head of a diesel engine whose cam shaft 5 exists in the upper part of a cylinder head 2 is brought up near the cap side so as to get rid of a gap (t) to the said cap end for uniting with a cam cap 18. A lubricating oil passage 21 for leading the lubricating oil accummulated in the upper part of the cylinder head 2 outside the cylinder head is protrusively provided in the circumferential wall part 11a of the locker case 11 being brought near, and as a trouble being apt to occur is restrained as far as possile, the locker case 11 is provided with a structure for leading out the lubricating oil in the upper part of the cylinder head to the outside, namely the cam cap structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an OHC which is provided with a rocker case and a rocker cover on a cylinder head and covers a valve operating system located above the cylinder head from the surroundings.
Relates to a rocker cover structure of an internal combustion engine.

[0002]

2. Description of the Related Art In a multi-valve diesel engine (internal combustion engine) represented by four valves, a fuel injection nozzle is installed inside a rocker chamber. Therefore, a rocker cover structure using a rocker case is used for fuel injection. The injection pipe connected to the injection nozzle is introduced from the outside into the rocker chamber.

This is a layout in which a fuel injection nozzle is arranged in the center of a combustion chamber, and two intake valves and two exhaust valves are arranged so as to surround the nozzle, and the fuel injection is performed like a two-valve type. This is because it is difficult to place the nozzle away from the valve train system equipment.

This structure has been widely adopted in an overhead camshaft (OHC) type diesel engine in which a camshaft is arranged above a cylinder. In such a rocker cover structure, as shown in FIGS. 6 and 7, a rocker case c composed of a frame-shaped peripheral wall having a low height is provided on the upper part of the cylinder head a so as to surround the valve mechanism b. The case c is attached to the upper end of the case c.
The rocker cover d is attached so as to close the.

An injection pipe f connected to the fuel injection nozzle e is provided outside through the rocker case c. The injection pipe f has a structure in which the divided pipe members g and h are connected by a connector i provided on the peripheral wall of the rocker case c.

[0006]

By the way, although the use of the rocker case c brings about excellent effects in the assembling property and the sealing property of the fuel injection nozzle e, there is an influence that the number of parts and the weight increase due to it. .

Therefore, by utilizing the rocker case c, an overhead camshaft (OHC) type valve mechanism b mounted on the upper part of the cylinder head a (a cam supported on the upper part of the cylinder head a by a cam cap o). It is considered that the shaft k is arranged to compose the valve operating mechanism) and the cylinder head a.

For example, in a gasoline engine, Japanese Patent Laid-Open No. 2-6
It has been proposed to form a cam cap on the cylinder head cover as disclosed in 7448. Specifically, this is a cam cap o that supports the cam shaft k and the peripheral wall portion of the cylinder head cover n attached to the cylinder head a among the two divided cylinder head covers m and n as shown in FIG. This is a structure in which a cam cap o is integrally formed with the cylinder head cover n by forming a connecting portion p for connecting the both in a gap t existing between the end and the end.

It is conceivable to apply this structure to the rocker cover structure. However, with this structure, although the number of parts constituting the engine, the number of assembling steps, and the like are reduced, the connecting portion p that fills the distance t between the end of each cam cap o and the wall of the cylinder head cover n is reduced. It is noticeable that the added weight increases.

Therefore, it cannot be said that the rocker case c is still fully utilized by this alone. This is because as the use of the locker case c progresses, many advantages can be brought while suppressing the defects.

Therefore, there is a demand for a rocker cover structure having many functions. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rocker case with a cam cap function and lubrication of a cylinder head while suppressing an increase in weight and an increase in size. An object of the present invention is to provide a multi-functionalized rocker cover structure for an internal combustion engine, which has a function of discharging oil to the outside.

[0012]

In order to achieve the above object, the invention described in claim 1 is a frame-shaped structure in which a camshaft is located above a cylinder head and which constitutes an internal combustion engine. In the rocker case, the peripheral wall portion of the rocker case facing the end portion of the cam cap is moved closer to the cap side so as to eliminate the gap between the end portion of the rocker case and the cam cap, and the peripheral wall portion of this rocker case is The lubricating oil passage is provided so as to project outward so as to supplement the above-mentioned amount of misalignment.

According to a second aspect of the invention, in addition to the above object, in order to fix the cam cap by utilizing a bolt for fixing the rocker case, the peripheral wall portion of the rocker case according to the second aspect, The case mounting hole for fixing the rocker case in the same peripheral wall portion is brought close to the position where it continuously communicates with the cap mounting hole in the cam cap,
It is integrated with the cam cap.

In addition to the above object, the invention set forth in claim 3 is intended to allow the lubricating oil accumulated in the upper portion of the cylinder head to be quickly returned to the oil pan of the internal combustion engine.
In the outer surface of the peripheral wall portion of the rocker case, the lubricating oil passage described in, the cylindrical portion that is opened to the inside of the rocker case most of the internal space, along with the axial center of the cam shaft, It is configured by forming an outflow portion toward the oil pan of the internal combustion engine in the cylindrical portion.

[0015]

According to the first aspect of the present invention, the cam cap is integrated with the peripheral wall portion of the rocker case which is moved closer to the cam cap, thereby increasing the weight, so that the cam cap end is separated from the peripheral wall portion of the rocker case. It is formed integrally with the rocker case without the need for a connecting portion that fills the filled portion.

In addition, the lubricating oil passage for discharging the lubricating oil accumulated in the cylinder head is formed on the outer surface of the rocker case by utilizing the empty portion generated by bringing the peripheral wall portion of the rocker case close as an installation space. Will be formed on the rocker case without making it unnecessarily large.

As a result, the rocker case contributes to the reduction of the number of parts of the internal combustion engine, that is, the function of allowing the lubricating oil of the cylinder head to be led to the outside and the cam cap function, while suppressing the possible troubles as much as possible. It is multifunctional.

According to the second aspect of the invention, the case mounting hole in the peripheral wall portion of the rocker case can also be used as a cap mounting hole for fixing the cam cap as it is. The cam cap can be fixed by using the fixing bolts.

As a result, the number of bolts for fixing the cam cap is reduced, and the number of parts can be further reduced accordingly. According to the invention described in claim 3, a large amount of the lubricating oil accumulated in the upper portion of the cylinder head is received from the opening of the lubricating oil passage, and the lubricating oil can be flown out from the outflow part to the oil pan of the internal combustion engine. As a result, the lubricating oil above the cylinder head can be quickly returned to the oil pan of the internal combustion engine.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in FIGS. Here, FIG. 1 shows an appearance of a rocker cover structure of a four-valve (multi-valve) internal combustion engine to which the present invention is applied, for example, a partially cut diesel engine,
2 shows an exploded perspective view of the rocker cover structure, FIG. 3 shows a plan view taken along line XX in FIG. 2, and FIG.
The sectional view which follows the YY line in the inside is shown.

In FIG. 1, reference numeral 1 denotes a cylinder block in which, for example, four vertically facing cylinders (not shown) are arranged in parallel along the longitudinal direction of the engine, and 2 denotes a cylinder mounted on the upper portion of the cylinder block 1. The head.

A valve mechanism 3 is mounted above the cylinder head 2. In the valve mechanism 3, a cam shaft 5 is arranged laterally of the combustion chamber (not shown) and near the outer peripheral portion of the cylinder head 2 along the front-rear direction of the engine to absorb the displacement of the cam shaft 5. An overhead camshaft system (OHC system) is used for transmitting to an intake / exhaust valve 8 located above a combustion chamber (not shown) through a rocker arm 6 and a rocker lever 7 for each exhaust. However, 5
Reference numeral a is a timing gear that receives rotation from a crankshaft (not shown), and reference numeral 9 is a rocker shaft that is arranged in parallel between the camshaft 5 and the combustion chamber and supports the rocker arm 6.

The intake / exhaust valves 8 are arranged so as to surround the fuel injection nozzle 10 provided in the center of the combustion chamber per cylinder, for example, two on the intake side and two on the exhaust side. (Multi-valve type) It is an OHC type valve operating system.

Further, on the outer periphery of the upper end of the cylinder head 2,
A frame-shaped rocker case 11 is provided upright. The rocker case 11 is composed of a peripheral wall that is continuous in the circumferential direction of the cylinder head 1 and has a low height.

The rocker case 11 is fixed by screwing a bolt 20 into the cylinder head 2 through case mounting holes 19 which are provided in each part of the peripheral wall and which are oriented vertically.
The peripheral wall surrounds the valve mechanism 3 located above the cylinder head 2 from the periphery.

Then, the peripheral wall of the rocker case 11 is penetrated, and the injection pipe 12 from each fuel injection nozzle 10 is piped to the outside. In addition, in the injection pipe 12, through the injection pipe through hole 13 formed in the peripheral wall of the rocker case 11,
Tube portion 12a in the cylinder head 2 and the cylinder head 2
A piping structure for connecting the outer pipe portion 12b with the connector member 14 is adopted.

The rocker case 11 has been improved not only to have a function of piping the injection pipe 12, but also to have a structure for supporting the camshaft 5 and a structure for discharging the lubricating oil 16 accumulated on the upper portion of the cylinder head 2 to the outside. There is.

That is, as is well known, in supporting the camshaft 5, a shaft portion serving as a supporting portion of the camshaft 5 is
A support base 17 formed on the upper surface of the cylinder head 2 and a cam cap 18 which is a separate body from the support base 17 are coupled to each other so that the support base 17 is rotatably supported by being sandwiched from both sides in the radial direction.

Here, the former structure (which also serves as a structure for supporting the camshaft 5) is one in which the rocker case 11 and the cam cap 18 are integrated. In this integrated structure, a coupling portion is formed in a gap between the end portion of the cam cap 18 and the peripheral wall portion 11a forming a side of the rocker case 11 facing the end portion as described in the above publication, and the cam cap is formed. 18 and the rocker case 11 are not integrated, but the peripheral wall portion 11a is formed so as to eliminate this gap.
Of the cam cap 1 to the cam cap 18 side
8 and the rocker case 11 are integrated.

Specifically, in the peripheral wall portion 11a of the rocker case 11, a case mounting hole 19 (a hole for fixing the rocker case 11) provided in the peripheral wall portion 11a is located near the peripheral wall portion 11a of the cam cap 18. To the position where it continuously communicates with the cap mounting hole 18a provided in
It is integrated with the cam cap 18.

In order to make this point easy to understand, the structure in which the conventional cam cap and the rocker case are separate bodies will be described. In the structure described above, there is a gap t as shown in FIGS. 6 and 7. The case mounting hole r of the rocker case c and the cap mounting hole s on the outside of the cam cap o, which are located apart from each other, are fitted to the peripheral wall portion of the rocker case c until the position where the case mounting hole s matches the cap mounting hole s. Can be said to be a structure in which the peripheral wall portion of the rocker case c and the cam cap o are integrated by bringing them closer to the combustion chamber side so as to eliminate the gap t.

With this structure, the cam cap 18 is integrated with the rocker case 11 while suppressing an increase in weight. At the same time, the case mounting hole 19 and the cap mounting hole 18a for fixing the cam cap 18 as it is
It has a structure that can be used as.

The latter structure (which also serves as a structure for guiding the lubricating oil 16 to the outside) has a peripheral wall portion 11a which is moved to the outside.
Further, in order to supplement the original width dimension of the rocker case 11 which becomes narrower due to the shifting, the structure in which the lubricating oil passage 21 is formed so as to protrude outward from the outer surface is used.

More specifically, as shown in FIGS. 1 to 4, a cylindrical portion 22 having a substantially C-shaped cross section is provided on the entire outer surface of the peripheral wall portion 11a in the engine front-rear direction (axial direction of the camshaft 5). ) Is formed along.

The protruding dimension of the tubular portion 22 is the same as the width dimension A of the rocker case 11 when the cam cap 18 is a separate body.
The difference C (empty portion) from the width dimension B of the rocker case 11 which is narrowed by integrating the cam cap 18 is set to be substantially the same.

That is, by forming the tubular portion 22, the outer shape of the rocker case 11 returns to the original width dimension A. The entire inner space of the cylindrical portion 22 is opened horizontally in the rocker case 11 through an opening 23 provided in the peripheral wall portion 11a, and is fed from an oil main gallery (not shown) to the cylinder head 2. A large amount of the lubricating oil 16 accumulated in the upper part can be received.

The end portion of the tubular portion 22 on the side of the timing gear 5a is a chamber portion 11 for accommodating the timing gear 5a.
An opening 24 (corresponding to an outflow portion) opening in b is formed, and the lubricating oil 16 received by the tubular portion 22 is transferred to the chamber portion 11
It can be returned to the oil pan of the diesel engine through b.

On the peripheral wall of the intermediate portion of the tubular portion 22, there is formed a mouth portion 25 (corresponding to the outflow portion) which projects laterally, and the lubricating oil 16 received even in the middle of the passage.
Can be returned to the oil pan of the diesel engine.

The remaining end of the passage (the end on the side opposite to the timing gear 5a) is closed by a cover plate 26. A rocker cover 27 that closes the upper opening of the rocker case 11 is attached to the upper end of the rocker case 11 to seal the valve mechanism 3 surrounded by the rocker case 11.

Looking at the rocker case 11 having the rocker cover structure thus constructed, the cam cap 1
8 and the lubricating oil passage 21 are added. Here, since the cam cap 18 is integrated with the peripheral wall portion 11a of the rocker case 11 that has been moved closer, the cam cap 18 does not need a connecting portion that fills the separated gap between the cam cap end and the peripheral wall portion of the rocker case. Moreover, since it is formed integrally with the rocker case 11, the weight of the rocker case 11 does not needlessly increase.

Moreover, since the lubricating oil passage 21 is formed on the outer surface of the peripheral wall portion 11a by using the empty portion generated by bringing the peripheral wall portion 11a of the rocker case 11 as an installation space, the outer shape of the rocker case 11 is unnecessary. The lubricating oil 16 accumulated on the upper portion of the cylinder head 2 can be returned to the oil pan without increasing the size.

This means that the rocker case 11 has a cam cap structure and a structure in which the lubricating oil 16 of the cylinder head 2 can be led out to the outside while suppressing the possible troubles as much as possible, thus reducing the number of engine parts. It can have multiple functions that contribute to.

Moreover, with the structure in which the lubricating oil passage 21 is provided in the peripheral wall portion 11a, the mounting method of the engine or the engine type is changed, such as the direction in which the cylinder is oriented vertically and the direction in which the cylinder is oriented horizontally. Also as a return system of the lubricating oil 16 in the cylinder head 2, the lubricating oil passage 2
1 has the advantage that it can be used.

Specifically, as shown in FIG. 5, in the case of an engine in which the cylinder is mounted so as to be oriented horizontally, the engine is installed so that the lubricating oil passage 21 is on the lower side, and the lubricating oil passage 21 The lubricating oil 16 is returned to the oil pan (not shown) from the mouth 25 of the above.

Further, the rocker case 11 for fixing the rocker case 11 is moved to a position where the case mounting hole 19 for fixing the rocker case 11 is continuously communicated with the cap mounting hole in the cam cap 18.
By adopting a structure in which the rocker case 11 and the cam cap 18 are integrated by pulling the peripheral wall portion 11a of the above, the case mounting hole 19 in the peripheral wall portion 11a is used as a cap mounting hole for fixing the cam cap 18 as it is. Can also be used for both.

As a result, the cam cap 18 can be fixed by utilizing the bolt 20 for fixing the rocker case 11, the number of bolts required for fixing the cam cap 18 can be reduced, and the parts can be further improved. The points can be reduced.

In addition, most of the internal space uses the tubular portion 22 opened in the rocker case 11, and the tubular portion 2
If a lubricating oil passage 21 having an outflow portion toward the oil pan is adopted in 2, it is possible to receive a large amount of the lubricating oil 16 accumulated in the upper part of the cylinder head 2 and let the lubricating oil 16 flow out to the oil pan of the engine. As a result, the lubricating oil 16 above the cylinder head 2 can be quickly returned to the oil pan of the engine.

In one embodiment, the present invention is applied to a two-stage rocker cover structure having a single rocker cover, but the present invention is not limited to this, and the rocker cover has two or more layers. It is needless to say that the present invention may be applied to a multi-stage rocker cover structure having the above structure.

[0049]

As described above, according to the invention as set forth in claim 1, while suppressing possible troubles such as an increase in weight and an increase in external size, as much as possible, The rocker case can be provided with a cam cap function and a function of guiding the lubricating oil of the cylinder head to the outside.

As a result, the number of parts in the internal combustion engine can be reduced rationally. According to the invention of claim 2, in addition to the effect of the invention of claim 1, the cam cap can be fixed by utilizing the bolt for fixing the rocker case.

As a result, the number of bolts for fixing the cam cap can be reduced, and the number of parts can be further reduced accordingly. According to the invention described in claim 3, in addition to the effect of the invention of claim 1, the effect that the lubricating oil accumulated in the upper portion of the cylinder head can be quickly returned to the oil pan of the internal combustion engine is brought about.

[Brief description of drawings]

FIG. 1 shows a rocker cover structure according to an embodiment of the present invention,
The perspective view shown with the head part of the OHC type diesel engine carrying the rocker cover structure.

[Fig. 2] From the cylinder head of the diesel engine,
The exploded perspective view which removed a rocker case, a rocker cover, a rocker shaft, a fuel injection nozzle, etc.

FIG. 3 is a plan view showing the plane of the rocker case along the line X-X in FIG. 1 together with the flow of lubricating oil.

FIG. 4 is a side sectional view of an upper portion of the engine taken along the line YY in FIG.

FIG. 5 is a cross-sectional view for explaining the flow of lubricating oil when the engine is mounted with the cylinders arranged horizontally.

FIG. 6 is a sectional view of a head portion of an OHC type diesel engine using a conventional rocker case.

FIG. 7 is a plan view of the rocker case.

FIG. 8 is a cross-sectional view illustrating a structure in which a cam cap is integrally formed with a conventional rocker case.

[Explanation of symbols]

2 ... Cylinder head 3 ... Valve operating mechanism 5
… Camshaft 6… Rocker arm 7… Rocker lever 8
... intake / exhaust valve 9 ... rocker shaft 10 ... fuel injection nozzle 11
... Rocker case 11a ... Peripheral wall 16 ... Lubricating oil 1
7 ... Support 18 ... Cam cap 19 ... Case mounting hole 2
DESCRIPTION OF SYMBOLS 1 ... Lubricating oil passage 22 ... Cylindrical part 23 ... Opening 24, 25 ... Opening, mouth part (outflow part) 2
7 ... Rocker cover.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location F02F 1/24 F02F 1/24 Q (72) Inventor Tatsuya Ueno 4-21 Shimomaruko, Ota-ku, Tokyo No. 1 Mitsubishi Motors Engineering Co., Ltd.

Claims (3)

[Claims] 1. A rocker case having a frame shape is provided on an upper portion of a cylinder head having a cam type valve operating mechanism in which a cam shaft is supported at a predetermined position by a cam cap, so as to surround the valve operating system. In a rocker cover structure of an OHC type internal combustion engine configured by providing a rocker cover at an upper end portion of the case so as to close an opening of the case, the rocker case has a peripheral wall portion of the rocker case facing an end portion of the cam cap. Is formed integrally with the cam cap by being moved toward the cap side so as to eliminate a gap between the cap end and the end of the cap, and a lubricating oil passage is formed in a peripheral wall portion of the rocker case.
A rocker cover structure for an OHC type internal combustion engine, wherein the rocker cover structure is provided so as to project outward so as to compensate for the amount of the shift. 2. The peripheral wall portion of the rocker case is moved up to a position where a case mounting hole for fixing the rocker case in the peripheral wall portion is in continuous communication with the cap mounting hole in the cam cap. The rocker cover structure for an OHC type internal combustion engine according to claim 1, wherein the rocker cover structure is integrated with a cam cap. 3. The lubricating oil passage has a cylindrical portion formed on an outer surface of a peripheral wall portion of the rocker case, the tubular portion having a large portion of an inner space opened with respect to an inner side of the rocker case along an axial center of the camshaft. The rocker cover structure for an OHC type internal combustion engine according to claim 1, wherein the outflow portion toward the oil pan of the internal combustion engine is formed in the cylindrical portion.