JPH0441209Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention (1) Industrial application field The present invention defines a valve train chamber in which a valve train is housed between a cylinder head and a head cover, and On the lower surface of the inner wall facing the valve chamber,
The present invention relates to a breather passage structure for an internal combustion engine in which a breather passage bored in the cylinder head is opened.

(2) Prior Art Conventionally, such a breather passage is opened directly into the valve train chamber.

(3) Problems to be Solved by the Invention In the conventional structure described above, there is a risk that lubricating oil droplets scattered by the rotation of the cam in the valve train may fall into the breather passage.

This invention was proposed in view of such circumstances,
Ribs integrally formed on the inner wall of the cylinder head can prevent lubricating oil droplets from falling into the breather passage as much as possible, increasing the rigidity of the cylinder head and simplifying the structure. The purpose is to provide a breather passage structure.

B. Structure of the invention (1) Means for solving the problem In order to achieve the above object, the present invention provides a breather passage structure for an internal combustion engine of the type described above, in which the lower surface of the inner wall of the cylinder head facing the valve chamber is A cylindrical protrusion having an insertion hole for a coupling bolt between the cylinder head and the cylinder block is integrally formed at a distance from the side surface of the inner wall thereof, It is characterized by integrally forming a rib that connects the cylindrical protrusions together and covers the opening end of the breather passage to the valve operating chamber from above with a gap.

(2) Function The above-mentioned special arrangement of the ribs prevents lubricating oil droplets caused by the rotation of the valve cam from falling and entering the opening end of the breather passage into the valve operating chamber as much as possible. This improves the torsional rigidity of the cylinder head as a whole.

(3) Embodiment Below, an embodiment of the present invention will be explained with reference to the drawings. First, in FIG. It has C1 and C2.

In each cylinder row C1, C2, a cylinder head 2 is superimposed and bonded to the upper surface of the cylinder block 1, and first and second head covers 3, 4 are detachably attached to the upper and side parts of the cylinder head 2. Installed. A valve train chamber 5 defined by the cylinder head 2 and both head covers 3 and 4 accommodates a valve train (see FIG. 2) for driving an intake valve 6i and an exhaust valve 6e.

Cylinder block 1 of both cylinder rows C1 and C2
The base of the engine is integrated, and a common breather chamber 7 communicating with the crank chamber is provided in the base. In the left cylinder row C, the cylinder block 1 and cylinder head 2 are provided with a breather passage 8 that connects the common breather chamber 7 and the valve train chamber 5, and the first head cover 3 has a breather passage 8 that connects the valve train chamber 5 and the valve train chamber 5. A breather chamber 10 is provided with a control valve 9 interposed therebetween. On the other hand, in the right cylinder row C2, a breather passage 8 is formed in the cylinder block 1 and cylinder head 2, connecting the common breather chamber 7 and the valve operating chamber 5. The breather chamber 10 also communicates with the left and right intake passages 13, 13 of the intake manifold 12 through a pipe line 11, and the right cylinder row C2
The valve train chamber 5 is connected to an air cleaner 15 via a pipe line 14.
will be communicated to.

The control valve 9 opens when the negative pressure in the intake passages 13, 13 increases during low-speed operation of the engine, and as a result of the opening of the control valve 9, combustion in the left cylinder row C1 is reduced. The blow-by gas flowing from the chamber to the crank chamber is transferred to the common breather chamber 7 → breather passage 8 → valve operating chamber 5 → control valve 9 → breather chamber 10.
→Flows through the pipe line 11 to the intake passages 13, 13. At this time, in the right cylinder row C2, fresh air is introduced from the air cleaner 15 through the conduit 14 into the valve operating chamber 5, and is further guided from the breather passage 8 to the common breather chamber 7.

Further, when the control valve 9 closes due to a small intake negative pressure during high-speed rotation of the engine, no blow-by gas flow occurs in the left cylinder row C1, and the common breather chamber 7 flows in the right cylinder row C2.
Blow-by gas flows through →breather passage 8 →valve operating chamber 5 →pipe line 14 to air cleaner 15.

Next, the structure of the opening end of each breather passage 8 to the valve train chamber 5 will be explained.
2 and 2 have the same structure, the parts related to the left cylinder row C1 will be described below together with the structure of the valve train.

In FIG. 2, the cylinder head 2 has intake and exhaust ports 17i and 17e that open into the combustion chamber 16.
are formed, and intake and exhaust ports 17i, 17
e is opened and closed by intake and exhaust valves 6i and 6e. These intake and exhaust valves 6i, 6e are connected to a valve guide 18.
It is supported by the cylinder head 2 via valve springs 19i and 18e so as to be able to rise and fall freely.
is biased in the closing direction.

The intake and exhaust valves 6i and 6e protrude into the valve operating chamber 5, and these intake and exhaust valves 6i and 6e are connected to a valve operating device 20 within the valve operating chamber 5.

The valve train 20 includes a camshaft 21, first and second cam followers 22 ₁ and 22 ₂ , first and second hydraulic tappets 23 ₁ and 23 ₂ , and an interlocking mechanism 35.

A single camshaft 21 that is linked to a crankshaft (not shown) is disposed above the intake valve 6i. It is rotatably supported by a cam holder 25 to which it is tied. Moreover, the camshaft 21 is provided with an intake cam 21i and an exhaust cam 21e corresponding to the intake and exhaust valves 6i and 6e. A first cam follower 22 ₁ is interposed between the intake cam 21i and the head of the intake valve 6i.
The base end of the cam follower 22 ₁ is connected to a first hydraulic tappet 23 ₁ installed in the support hole 26 ₁ of the cylinder head 2.
It is supported so that it can swing freely.

An intermediate portion of one side of the second cam follower 22 ₂ is in sliding contact with the exhaust cam 21e on the exhaust valve 6e side. One end, that is, the lower end of this second cam follower ₂₂₂ is
It is swingably supported by a second hydraulic tappet 23 ₂ installed in another support hole 26 ₂ of the cylinder head 2 . Further, the other end, that is, the upper end of the second cam follower 22 ₂ is connected to the exhaust valve 6e via the interlocking mechanism 35.

The interlocking mechanism 35 includes a bell crank-shaped rocker arm 28 whose one end engages with the head of the exhaust valve 6e to open and close the exhaust valve 6e, and which is swingably supported by the cylinder head 2 via the rocker shaft 27. ,
A push rod 29 is interposed between the other end of the rocker arm 28 and the other end of the second cam follower ₂₂₂ .
It consists of

3 and 4, a recess 30 is formed on the lower surface _WL of the inner wall of the cylinder head 2 facing the valve chamber 5, adjacent to the side surface _WS of the inner wall. , the opening end of the breather passage 8 to the valve operating chamber 5 is open. In the recess 30, a cylindrical protrusion 32 is provided with an insertion hole 31 through which a bolt (not shown) for coupling the cylinder head 2 to the cylinder block 1 is inserted.
It will be erected in one piece with a gap from W _S. The upper end side surface of the protrusion 32 and the inner wall side surface W _S of the cylinder head 2 are integrally connected by a rib 33 formed integrally with the inner wall side surface W _S . The torsional rigidity of the protrusion 32 and, by extension, of the cylinder head 2 as a whole can be improved.

An oil supply passage 34 for supplying lubricating oil to the first hydraulic tappet 23 ₁ is bored in the rib 33 . Further, the rib 33 covers the opening end of the breather passage 8 to the valve operating chamber 5 from above with a gap provided therebetween.

Next, to explain the operation of this embodiment, blow-by gas flows in the breather passage 8 of the cylinder row C1 on the left, and blow-by gas and fresh air flow in the breather passage 8 of the cylinder row C2 on the right. However, above the opening end of these breather passages 8 to the valve operating chamber 5 is a rib 33.
covered with. Therefore, the gas flows around the cylindrical protrusion 32 and enters the breather passage 8.
and the valve operating chamber 5. Moreover, the valve chamber 5
Inside, lubricating oil is scattered by the rotation of suction and exhaust cams 21i and 21e in accordance with the rotation of the camshaft 21. Even if this lubricating oil droplets fly above the breather passage 8, the breather The rib 33 above the passage 8 prevents it from falling directly into the breather passage 8. Further, by applying lubricant oil droplets to the ribs 33, the effect of cooling the oil flowing in the oil supply path 34 can also be obtained.

C. Effects of the invention As described above, according to the invention, on the lower surface of the inner wall of the cylinder head facing the valve train chamber, bolts for coupling between the cylinder head and cylinder block are provided at a distance from the side surface of the inner wall. A cylindrical protrusion having an insertion hole is integrally formed, and an opening end of the breather passage to the valve operating chamber is formed on the inner wall side of the cylinder head, and the inner wall side and the cylindrical protrusion are integrally connected. Since a rib is integrally formed from above to cover the valve with a gap, the rib effectively prevents lubricating oil droplets caused by the rotation of the valve cam from falling and entering the opening end of the breather passage into the valve chamber. Not only can this be prevented, but also the torsional rigidity of the cylindrical protrusion and, by extension, the entire cylinder head integrated therewith can be improved. Moreover, the common rib can be used both as a means to prevent the lubricating oil droplets from falling into the opening end of the breather passage and as a means to increase the rigidity of the cylindrical protrusion and cylinder head, so the number of parts can be reduced accordingly. This can contribute to simplifying the structure and reducing the weight of the cylinder head.

In addition, if an oil supply passage to the valve train is bored in the rib as in the embodiment, the oil supply passage becomes easier to manage, and the hollow cross-sectional structure of the rib provides the required rigidity of the entire rib. It becomes possible to reduce the weight while ensuring the same.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and Fig. 1 shows a blow-by gas return system, Fig. 2 shows an enlarged vertical side view of the valve train, and Fig. 3 shows the opening end of the breather passage. Enlarged longitudinal cross-sectional view, Figure 4 is the 3rd
It is a sectional view taken along the line - in the figure. 2... Cylinder head, 3, 4... Head cover, 5... Valve train chamber, 8... Breather passage, 20...
... Valve gear, 32 ... Cylindrical protrusion, 33 ... Rib,
34...Refueling route.

Claims (1)

[Claims for Utility Model Registration] (1) A valve train chamber 5 in which a valve train 20 is housed is defined between the cylinder head 2 and the head covers 3 and 4, and a valve train chamber 5 in which a valve train 20 is housed is defined. In a breather passage structure for an internal combustion engine in which a breather passage 8 bored in the cylinder head ₂ is opened on the lower surface WL of the inner wall facing the cylinder head 2, the lower surface WL of the inner wall of the cylinder head ₂ has a side surface _WS of the inner wall.
The insertion holes 31 for the coupling bolts between the cylinder head 2 and the cylinder block 1 are spaced apart from each other.
_{A cylindrical} protrusion 32 with A breather passage structure for an internal combustion engine, characterized in that a rib 33 is integrally formed to cover an opening end to a valve chamber 5 from above with a gap. (2) The breather passage structure for an internal combustion engine according to claim 1, wherein the rib 33 is provided with an oil supply passage 34 to the valve train 20.