JPS595131Y2 - Internal combustion engine breather device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a breather device for an overhead valve type internal combustion engine.

FIG. 1 shows an example of a conventional overhead valve type spark ignition internal combustion engine.

In the figure, 101 is a crankcase 102 is a cylinder head, 103 is an intake valve, 104 is a piston, 105 is a cylinder, 106 is a connecting rod, 107 is a crankshaft, 10
8 is the intake cam, 109 is the tapetsu l-1110 is the push rod, 1
11 is a rocker arm, and 112 is a spark plug.

In this type of internal combustion engine, the reciprocation of the piston 104 and the movement from the combustion chamber in the cylinder 105 to the crank chamber 113 are generally performed.
The pressure inside the crank chamber 113 increases due to blow-by gas etc. leaking inside.

For this reason, the breather valve 014 is installed in the crankcase 101.
A breather 014 equipped with
The pressure inside 13 is kept below a certain value.

That is, when the pressure in the crank chamber 113 exceeds a certain value, the breather valve 014a opens and the mixed gas of air and oil droplets in the crank chamber 113 collides with the plate surface of the breather valve 014a, separating the oil and leaving only air. is discharged to the outside.

In addition, the valve train, which includes an intake valve 103, an exhaust valve (not shown), a rocker arm 111, etc., pumps lubricating oil 017 accumulated in the lower part of the crankcase 101 through an oil pipe 016.
The lubricant is lubricated by injecting the oil into the valve train chamber 018 through the valve 21.

The oil that lubricates the valve gear passes through the push rod chamber 019 and enters the oil return hole 0.
20 and returned into the crank chamber 113.

However, in such a conventional internal combustion engine, (1) the breather 014 is directly connected to the crankcase 101, so that the pressure inside the crank chamber 113, which is fluctuated by the reciprocating motion of the piston 104, is Therefore, oil and air are difficult to separate within the breather 014, and gas mixed with oil is often discharged to the outside.

This tendency is particularly noticeable when the engine is operated at an angle.

(2) Pump 016 for supplying lubricating oil to the valve train
, oil pipe 021, etc., the structure of the engine becomes complicated and the manufacturing cost increases.

There were problems such as.

A breather device for an internal combustion engine previously proposed by the applicant (Utility Model Application No. 54-48422, Utility Model Application No. 55-14
No. 9508).

A case where this device is applied to an overhead valve type four-stroke spark ignition internal combustion engine will be explained with reference to FIGS. 2 and 3.

In the figure, numerals 101 to 113 indicate the same members as those in FIG. 1, and 114 is an exhaust valve.

115 is a cylinder head cover for covering the valve train from the intake valve 103, exhaust valve 114, rocker arm 111, etc.; 116 and 117 are push rod chambers for housing the push rod 110; and 118 is a cylinder head cover for housing the valve train. This is the valve gear room.

The above configuration is similar to the conventional one.

119 is the push rod chamber 116, 117 and the crank chamber 113.
This is a communication hole for communicating with the valve train chamber 11.
8 communicates with the crank chamber 113 via push rod chambers 116 and 117 and the communication hole 119.

A breather 120 is attached to the upper part of the crankcase 101 and includes an inner chamber 120a, a check valve 120b, an exhaust port 120C to the atmosphere, and the like.

The inner chamber 120a of the breather 120 is connected to the crankcase 101. Air passages 121 and 122 are formed in the cylinder head 102 and the cylinder head cover 115, respectively.
It communicates with the upper part of the valve train chamber 118 via 123 .

The check valve 120b is a so-called plate valve with an inner chamber 120.
It is formed so that gas can flow only from side a toward the atmosphere.

124 is lubricating oil 1 stored at the bottom of the crankcase 101
Connecting rod 106 is an oil-scraped plate for flipping up 25.
is fixed to the bottom edge of the

Reference numeral 126 denotes a small hole bored in the bottom wall of the inner chamber 120a of the breather 120, and the inner chamber 120a and the crank chamber 113 communicate with each other through the small hole 126.

The small hole 126 is formed to have a sufficiently smaller diameter than the communicating hole 119.

In the above device, when the pressure in the crank chamber 113 rises during engine operation, the gas in the crank chamber 113 flows into the communication hole 111 along with oil droplets splashed up by the oil scraper plate 124.
The oil enters the valve train 118 through the push rod chambers 116, 117, where it collides with the inner wall of the cylinder head cover 115 and each member 103, 111, 114 of the valve train, whereby oil and air are separated.

The separated oil is transferred to the push rod chamber 117, 1 that lubricates the valve gear.
16 and a communication hole 119 and are returned to the crank chamber 113.

The gas in the valve train chamber 118 containing some oil enters the air passage 123 of the cylinder head cover 115 through the intake port 123a provided at the upper part of the valve train chamber 118.
Breather 120 (7) via air passage 122.121
It flows into the interior chamber 120a, where the oil and air are again separated.

The air separated in the inner chamber 120a of the breather 120 pushes open the check valve 120b and is discharged into the atmosphere from the discharge port 120C.

Further, the oil in the inner chamber 120a is allowed to fall into the crank chamber 113 through the small hole 126.

As mentioned above, the oil content of the gas in the crank chamber 113 is separated in two places, the valve train chamber 118 and the inner chamber 120a of the breather 120, so that the oil content is completely separated and the gas is removed from the exhaust port 120C along with the air. No oil is discharged.

Further, since the valve train is lubricated by the oil separated within the valve train chamber 118, a lubricating oil pump like the conventional one is not required.

As described above, the breather device for an internal combustion engine of this proposal communicates the valve train chamber and the crank chamber through the push rod chamber, while the breather device communicates with the atmosphere through the valve train chamber and the check valve. An air passage was provided to communicate with the inner chamber of the
The passage of gas from the crank chamber becomes longer, and the gas in the crank chamber is separated from oil and air in two places: the valve train chamber at the top of the engine and the inner chamber of the breather. can be reliably separated from air.

Therefore, oil is not discharged into the atmosphere from the breather.

In addition, since the valve train is lubricated by the oil splashed into the valve train chamber together with the gas in the crank chamber, a lubricating oil pump, lubricating oil pipe, etc., are installed to lubricate the valve train as in the conventional system. This simplifies the structure of the engine and reduces manufacturing costs.

However, in this device, the air passages in a portion of the cylinder head cover merely represent holes conceptually.

The purpose of the present invention is to provide an air passage structure for the cylinder head cover that is improved in terms of performance, external dimensions, and cost. In addition, the air inlet of the air passage is provided on the opposite side of the push rod chamber with respect to the rocker shaft.

In this case, the following improvements to the air passage of the cylinder head cover are realized.

(a) Since the shape is die-castable and the number of machined parts is reduced, costs are reduced.

(b) The population of the air passage is determined by considering the inclination, the lubrication of the valve train parts, and the relative position with the push rod nitrogen outlet.
Tilting performance and durability are improved.

(c) Since the air passage is placed on the side surface of the cylinder head cover, the overall height is reduced.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 is a longitudinal sectional view showing a part of a cylinder head cover provided with an air passage according to an embodiment of the present invention, FIG. 5 is a sectional view taken along line A-A in FIG. 4, and FIG. FIG. 3 is a sectional view taken along line BB in the figure.

In the figure, 1 is a cylinder head, 2 is a cylinder head cover, 3 is a gasket, 4 is a rocker arm, 5 is a rocker shaft, 6 is a push rod, 7 is an adjustment screw, 8 is a nut, 9 is a spring holder, 10 is a valve spring, 11 is a valve, 12 is a valve guide, 13 is a collar, 14 is a rocker shaft tightening bolt, 15 is a cylinder head cover tightening screw, and 16 is a cylinder head tightening bolt.

01 is an air passage provided in the cylinder head, and corresponds to the passage 122 in FIG. 3.

02.02', 02'' are air passages provided in the cylinder head cover 2, 02' is an air passage, and 02'' is its outlet, which communicates with the air passage 01 of the cylinder head.

06 is an outlet of a push rod chamber (corresponding to the push rod chamber 117 in FIG. 2 and communicating with the crank chamber) provided in the cylinder head.

04 is a small hole for lubrication provided in the rocker arm 4.

The operation in the case of the above configuration will be described.

In an internal combustion engine, a breather valve is provided to relieve the pressure in the crank chamber that increases due to the reciprocating movement of the piston and blow-by gas.

Oil dip in small 4-stroke engines
Splash lubrication by er) is often adopted.

It is known to take a breather through the cylinder head cover and to lubricate the valve train parts in the upper part of the cylinder head by placing oil droplets on this air flow.

From FIG. 4 to FIG. 6, gas and oil droplets from the crank chamber exit from the push rod nitrogen outlet 06 and enter the chamber in the upper part of the cylinder head.

Here, the gas and oil separate and lubricate the valve train parts, and the oil returns to the crank chamber from the push rod outlet 06 (most of the oil in the form of droplets collides with the cylinder head cover 2 etc. in this chamber and separates). .

Gas enters through the air passage inlet 02 hole in the cylinder head cover, passes through the passage 02', enters the cylinder head passage 01 through the outlet 02'', and is discharged to the outside of the engine through a breather valve (not shown).

The remaining oil is also separated in this passage, so when it is released, only gas is left.

Since the position of the inlet 02 is on the opposite side of the push rod outlet 06 with respect to the centerline C-C of the rocker shaft in FIG. The separated oil enters through the small hole 04 and provides sufficient lubrication.

In the figure, the arrow indicates the flow of gas containing oil, and the arrow indicates the return of separated oil.

The present invention as described above has the following effects.

(1) Air passage 0 formed in cylinder head cover 2
2' has a shape that can be die cast, so it is inexpensive.

(2) The air population 02 is the “rocker axis center line C” as described above.
-C is provided on the opposite side of the push rod outlet 06, so complete lubrication is achieved.

(3) Since the air port 02 is provided on the upper side, oil will not be spewed out due to inclination.

Furthermore, since the air passage 02' is arranged on the side surface of the cylinder head cover 2, the height of the cylinder head cover 2 is not increased.

FIG. 7 shows another embodiment of the air passage according to the present invention.

In this case, the air population 02 is not a hole but a slit.

Therefore, it is possible to cast through die casting without requiring drilling by machining.

However, the slope becomes slightly worse. FIG. 8 shows yet another embodiment of the air passage according to the present invention.

In this case, the passage 02' is shaped like a labyrinth.

Separation of oil takes place more completely.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a conventional overhead valve type 4-stroke spark ignition engine, Fig. 2 is a longitudinal sectional view of an overhead valve type 4-cycle spark ignition engine equipped with an improved breather device, and Fig. 3 is a longitudinal sectional view of a conventional overhead valve type 4-stroke spark ignition engine. 4 is a vertical sectional view showing a part of a cylinder head cover provided with an air passage according to an embodiment of the present invention; FIG. 5 is a sectional view taken along line III-III in the figure; FIG. 6 is a sectional view taken along line B-B in FIG. 4, FIG. 7 is an explanatory view showing an air passage of another embodiment of the present invention,
The figure is an explanatory view showing an air passage in yet another embodiment of the present invention. 1... Cylinder head, 2... Cylinder head cover, 4... Rocker arm, 5...
...Rocker shaft, 6...Push rod, 11...
...Valve, 01...Cylinder head air passage,
02...Inlet of the air passage of the cylinder head cover, 02'...The same air passage, 02''...
・Outlet of the same air passage, 04...Small hole for lubrication 1.
06...Push bar nitrogen outlet.

Claims (1)

[Scope of utility model registration request] The push rod chamber, which accommodates valve drive members such as push rods that drive the intake valves or exhaust valves, is communicated with the crank chamber and the valve train chamber formed at the top of the cylinder head, and air, oil, etc. are provided at the top of the crankcase. At the same time, an air passage is formed that communicates the inner chamber of the breather with the upper part of the valve train chamber, and there is no space between the inner chamber of the breather and the atmosphere from the inner chamber. A check valve that only allows fluid to flow toward the atmosphere is provided, and the gas in the crank chamber is guided through the push rod chamber to the valve gear chamber, where oil is separated, and then through the air passage to the inner chamber of the breather. In a breather device for an internal combustion engine, the oil is separated again and only the air is discharged to the atmosphere.The air passage of the cylinder head cover that forms the valve train chamber is provided on the side of the cylinder head cover, and the air passage is connected to the air passage. A breather device for an internal combustion engine, characterized in that an air inlet is provided on a side opposite to the push rod chamber with respect to the center line of the rocker shaft in the valve train chamber.