JPS595130Y2 - 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 which 1 is a crankcase 2 is a cylinder head, 3 is an intake valve, 4 is a piston, 5 is a cylinder, 6 is a connecting rod, 7 is the crankshaft, 8 is the intake cam, 9 is the tappet, 1
0 indicates a push rod, 11 indicates a rocker arm, and 12 indicates a spark plug.

In this type of internal combustion engine, the pressure in the crank chamber 13 generally increases due to the reciprocating movement of the piston 4 and blow-by gas leaking into the crank chamber 13 from the combustion chamber in the cylinder 5.

For this purpose, a breather 014 equipped with a breather valve 014a is attached to the crankcase 1, and from there the breather 014 is connected to the crank chamber 1.
The gas 015 inside the crank chamber 13 is discharged to the outside, and the pressure inside the crank chamber 13 is kept below a certain value.

That is, when the pressure in the crank chamber 13 exceeds a certain value, the breather valve 014a opens and the mixed gas of air and oil droplets in the crank chamber 13 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 consisting of an intake valve 3, an exhaust valve (not shown), a rocker arm 11, etc., uses a pump 016 to blow out oil 017 accumulated in the lower part of the crankcase 1 through an oil pipe 021 into a valve train chamber 018. It is lubricated by dampening.

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 13.

However, in such a conventional internal combustion engine, (1) the breather 014 is directly attached to the crankcase 1, and therefore the pressure within the crank chamber 13, which is varied by the reciprocating motion of the piston 4, acts directly on the breather valve 014a. 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) The valve train is a pump 016 for supplying lubricating oil.
, oil pipe 021, etc., the structure of the engine becomes complicated and the manufacturing cost increases.

There were problems such as.

The present invention has been devised in view of the above, and an object of the present invention is to provide a breather device that is simple in structure and inexpensive to manufacture, capable of reliably separating oil and air, and allowing the separated oil to act as a lubricant for a valve train. With the goal.

For this reason, the present invention attaches a breather equipped with a check valve to the upper end of the crankcase, communicates the valve train chamber in the upper part of the cylinder head with the crank chamber via a push rod chamber, and connects the inner chamber of the breather to the valve train. An air passage is formed that communicates with the upper part of the chamber, and the gas in the crank chamber is guided into the valve train chamber through the push rod chamber, and the valve train is lubricated with oil in the gas. It is characterized by completely separating oil from air in the breather and releasing only the air to the outside.

The present invention will be described below with reference to Figures 2 and 3.
To explain one embodiment applied to a cycle spark ignition internal combustion engine, 1 is a crankcase, 2 is a cylinder head,
3 is an intake valve, 4 is a piston, 5 is a cylinder, 6 is a connecting rod, 7 is a crankshaft, 8 is an intake cam, 9 is a tappet, 10
is a push rod, 11 is a rocker arm, 12 is a spark plug, 1
3 is a crank chamber, and 14 is an exhaust valve.

15 is a cylinder bed cover for covering the valve train consisting of the intake valve 3, the exhaust valve 14, the rocker arm 11, etc.;
Reference numerals 16 and 17 are push rod chambers for accommodating the push rod 10, and 18 is a valve train chamber in which the valve train is accommodated.

The above configuration is the same as the conventional one.

19 is a communication hole for communicating the push rod chambers 16, 17 and the crank chamber 13, and the valve train chamber 18 is communicated with the crank chamber 13 via the push rod chambers 16, 17 and the communication hole 19. .

A breather 20 is attached to the upper part of the crankcase 1 and includes an inner chamber 20a, a check valve 20b, an exhaust port 20C to the atmosphere, and the like.

The inner chamber 20a of the breather 20 is the crankcase 1;
The cylinder head 2 and the cylinder head cover 15 are communicated with the upper part of the valve train chamber 18 through air passages 21, 22, and 23, respectively.

The check valve 20b is a so-called plate valve and is formed so that gas can flow only from the inner chamber 20a toward the atmosphere.

Reference numeral 24 denotes an oil scraper plate for splashing upward the lubricating oil 25 stored at the bottom of the crankcase 1, and is fixed to the lower end of the connecting rod 6.

26 is a small hole bored in the bottom wall of the inner chamber 20a of the breather 20, and the small hole 26 connects the inner chamber 20a and the crank chamber 13.
is communicated.

The small hole 26 is formed to have a sufficiently smaller diameter than the communicating hole 19.

In the above device, when the pressure in the crank chamber 13 increases during engine operation, the gas in the crank chamber 13 is transferred to the oil scraper plate 2.
4, the oil droplets splashed up by the oil droplets enter the valve train chamber 18 from the communication hole 19 through the push rod chambers 16 and 17, where the inner wall of the cylinder head cover 15 and each member 3 of the valve train enter the valve train chamber 18.
, 11.14, the oil and air are separated.

The separated oil lubricates the valve gear in the push rod chamber 17.16
and is returned to the crank chamber 13 via the communication hole 19.

The gas in the valve gear chamber 18 containing some oil enters the air passage 23 of the cylinder cover 15 through the intake port 23a provided at the upper part of the valve gear chamber 18, and enters the air passage 22.
21 into the interior chamber 20a of the breather 20, where the oil and air are again separated.

The air separated in the inner chamber 20a of the breather 20 pushes open the check valve 20b and is discharged into the atmosphere from the discharge port 20C.

In addition, the oil in the inner chamber 2Oa is leaked from the small hole 26 to the crank chamber 1.
He was forced to fall within 3 seconds.

As mentioned above, the gas in the crank chamber 13 is transferred to the valve train chamber 1.
Since the oil is separated at two locations, inside the breather 8 and inside the inner chamber 20a of the breather 20, the oil is completely separated and is not discharged together with air from the discharge port 20C.

Further, since the valve train is lubricated by the oil separated within the valve train chamber 18, a lubricating oil pump like the conventional one is not required.

As described above, the breather device for an internal combustion engine according to the present invention is
An air passage is provided to communicate the valve gear chamber and the crank chamber via the push rod chamber, and to communicate the valve gear chamber and the inner chamber of the breather which is communicated with the atmosphere via the check valve. Therefore, the passage from the crank chamber to the breather device becomes longer, and the gas in the crank chamber is separated into oil and air in two places: in the valve train chamber at the top of the engine and in the inner chamber of the breather. This allows the oil to be reliably separated from the 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. There is no need for this, the structure of the engine is simplified, and the manufacturing cost is also reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view taken along the cylinder axis and perpendicular to the crank axis, showing an example of a conventional overhead valve type four-cycle spark ignition internal combustion engine. 2 and 3 show an embodiment of the present invention, FIG. 2 is a diagram corresponding to FIG. 1, and FIG. 3 is a diagram showing III-II of FIG.
It is a sectional view along I line. 1... Crank case, 2... Cylinder head, 3... Intake valve, 10... Push rod, 14... Exhaust valve, 13 ...Crank chamber, 16.17...Push rod room, 18...
・Valve gear room, 19... Communication hole, 20...
... Breather, 20 a ... Inner chamber of IJ-za, 20 b ... Check valve, 21, 22. 23 ...
...Air passage, 26...Small hole.

Claims (1)

[Scope of utility model registration request] A push rod chamber in which a valve driving member such as a push rod for driving an intake valve or an exhaust valve is housed is communicated with a crank chamber and a valve train chamber formed in the upper part of the cylinder head, and the valve train chamber on the upper wall of the crankcase is connected to A breather for separating air and oil, etc. is installed below the equipment chamber, and an air passage is formed to communicate the inner chamber of the breather with the upper part of the valve train chamber. A check valve is installed between the inner chamber and the atmosphere to allow fluid to flow only from the inner chamber toward the atmosphere, and the gas in the crank chamber is guided to the valve gear chamber through the push rod chamber and oil is separated. 1. A breather device for an internal combustion engine, characterized in that the oil is introduced into the inner chamber of the breather through the air passage, the oil is separated again, and only the air is discharged to the atmosphere.