JPS6030407Y2 - Internal combustion engine breather device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an improvement in a breather device for an internal combustion engine.

As a conventional device of this kind, there is a lubricating device for a single cylinder OHV engine shown in Utility Model Application No. 55-9842.
The figure is a sectional view of the main parts of the engine.

In the figure, an engine E is driven by a piston 4, a crankshaft 5, a camshaft 6, and a camshaft 6 inside an outer shell structure such as a crankcase 1, a head block 2, and a rocker cover 3 that integrally form a cylinder barrel. It accommodates moving members such as a valve train V and intake/exhaust valves 7A and 7B.

The above-described valve train V includes a tappet 9 and a bushing rod 10 that run vertically through the tappet chamber 8, and a bushing rod cover 12 that covers the outer surface of the rod 10 and is installed between the tappet chamber 8 and the rocker chamber 11. The rocker arm 13 is housed in the rocker chamber 11, a rocker arm shaft 14, a rocker arm bracket 15, and the like.

A reed valve type blazer device 16 is attached to the open end surface of the tappet chamber 8.

The blazer device 16 and the crank chamber 17 are communicated through a ventilation passage P passing through the locker chamber 11.

This ventilation passage P includes first and second passages PI and P2 formed in the cylinder peripheral wall and the inner wall of the head block 2, respectively, in order to communicate the lowest part of the crank chamber 17 and the rocker chamber 11. It is composed of a rocker chamber 11, a space inside a bushing rod cover 12, and a tappet chamber 8.

As shown in FIG. 2, two of the eleventh and second passages PI and P2 are formed in front and back in parallel.

In the figure, reference numeral 18 is a spoon for scooping up oil, 19 is a pleather pipe that guides blow-by gas to the air cleaner 20,
Reference numeral 21 designates a commonly known oil return hole in the bottom wall of the tappet chamber 8.

When the diameter of this oil return hole 21 is 1 to 2 mm,
The hole diameter of the first and second passages PI and P2 is approximately 6.5
It is set to mm.

As described above, when the ventilation passage P is formed via the rocker chamber 11, the mist-like oil filling the crank chamber 17 is reliably removed from the rocker chamber 11 as the blow-by gas moves.
This allows the rocker arm 13 and rocker arm shaft 14 to be sufficiently lubricated.

Furthermore, since the direction of gas movement is reversed within the locker chamber 11,
Most of the mist oil is liquefied in the same chamber 11, and the first,
It flows down into the crank chamber 17 via the second passages Pi and P2.

Incidentally, mist-like oil is also separated in the tappet chamber 8 due to a sudden change in the cross-sectional area of the ventilation passage, and the liquefied oil flows from the oil return hole 21 to the crank chamber 17.
Flow inward.

In the above example, the oil return hole 21 is connected from the bottom wall of the tappet chamber 8 to the crank chamber 17.

Although the average value of the crank chamber internal pressure is negative due to the reed valve type blazer device 16, it fluctuates between positive and negative as the engine rotates.

In any case, since the pressure in the crank chamber 17 and the tappet chamber 8 is the same, if the diameter of the oil return hole 21 is small, the oil return effect will be weak.

Therefore, oil is ejected from the pleather pipe 19 during inclined operation.

The purpose of the present invention is to provide a breather device that can prevent oil from spewing out together with blow-by gas.The main features of this device include a main breather chamber that connects the breather chamber to the locker room, and a sub-breather chamber that connects the air cleaner. In a breather device for an internal combustion engine that is divided into a chamber and a chamber via a pleather pipe, a communication path is provided that communicates either or both of the breather main chamber or the breather auxiliary chamber with the crank chamber, and the breather main chamber and the crank chamber are connected to each other. A check valve is provided in the communication path between the two to allow fluid to flow only from the main breather chamber to the crank chamber.

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

FIG. 3 is a cross-sectional view showing essential parts of an OHV engine according to an embodiment of the present invention, FIG. 4 is a cross-sectional view taken along the line A-A in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line B-B in FIG. FIG.

In the figure, 31 is a crankcase formed integrally with the cylinder barrel, 32 is a cylinder head, 33 is a head cover, 34 is a piston, 35 is a crankshaft, 36 is a camshaft, 37 is a valve, 38 is a rocker arm, and 39 is a Bush rod, 40 is a tappet.

Reference numeral 41 denotes a breather chamber, which is composed of a main breather chamber 61 formed in the crankcase 31 and a sub-breather chamber 62 on the side of the breather chamber 1i42. ) 44 with a breather valve 43 provided therein.

45 is a small oil return hole, 46 and 47 are bushing rod chambers formed integrally with the crankcase 31 and cylinder head 32, respectively, 48 is a blow-by gas hole drilled in the head cover 33, 49 is a pipe, 50 is an air cleaner,
51 is a tappet hole, and 52 is a hole provided in the middle of the tappet hole 51, which connects the crank chamber C and the bushing rod chamber 46 formed in the crankcase 31.

53 is a restraining plate for the breather valve 43, and 54 is a blow-by gas passage provided in the head cover, which connects the hole 48 and the hole 55 in the head cover.

The hole 55 is a hole drilled in the blade cover 33, the cylinder head 32, and the crankcase 31, and is a blow-by gas passage that connects the breather main chamber 61 and the hole 54.

In addition, D is an oil scraping board.

The blow-by gas in the crank chamber C separates the oil mist which enters the rocker chamber R through the bushing rod chambers 46 and 47, lubricates the inner members of the rocker chamber, and passes through the hole 48, the passage 54, and the hole 55. This leads to the breather main room 61.

Further, the air is discharged from the breather main chamber 61 through a hole provided in the breather plate 44 to the air cleaner 50 via the breather sub chamber 62 and the pipe 49.

This is due to the action of the breather valve 43 (made of oil-resistant rubber or the like).

Blowby gas is accompanied by oil in the form of a mist, but this oil needs to be returned to the crank chamber C.

As in the conventional example shown in FIG.
Providing the small hole 45 that directly communicates the crank chamber C with the main breather chamber 61 has the same pressure in the main breather chamber 61 and the crank chamber C, so the oil return effect is small.

Note that if the diameter of the small hole 45 is increased, the blow-by gas is directly discharged from the small hole 45 without passing through the rocker chamber R, so that the internal materials of the rocker chamber R cannot be lubricated.

As a countermeasure to this problem, the present invention relates to an oil return device provided between the crank chamber C and the breather chamber 41, and a first embodiment thereof is shown in FIG.

In the same figure, a ball 56 and a spring 5 are placed in the middle of the small oil return hole 45.
7 is installed, and if there is a pressure phase difference, it will be slightly improved over the conventional one shown in FIG.

FIG. 8 shows a second embodiment of the present invention, and FIG. 9 shows a third embodiment, which is the same as that shown in FIG. 3 above.

The ones shown in FIGS. 8 and 9 are provided with a small hole 45 that communicates the chamber after the main breather chamber 61, that is, the sub-breather chamber 62, with the crank chamber C.

The average value of the internal pressure of the crank chamber C is negative, and the breather subchamber 62
Since the pressure is at atmospheric pressure, the oil, that is, the mist-like oil flowing together with the blow-by gas, collides with each part and the separated oil returns smoothly even in the small holes.

The one shown in FIG. 8 is the best because the ball 56 and spring 57 form a check valve.

In the case shown in FIG. 9, good results can be obtained by appropriately selecting the diameter of the small hole 45.

If the diameter is too large, there will be no pressure difference, and if it is too small, the return will be poor.

That is, in this case, the blow-by gas and mist oil in the crank chamber C are distributed through the rocker chamber R1 hole 48, passage 54, and hole 55.
In this order, the air passes through the breather valve 43 which leads to the breather main chamber 61 and enters the breather sub chamber 62.

The oil separated in the breather subchamber 62 returns to the crank chamber C via the passage 45.

In this case, the diameter of the passage 45 is suitably 4 to 0.5 mm.

The inside of the breather main chamber 61 communicates with the crank chamber C, and if there were no breather valve 43, it would show pulsation with an average positive pressure due to crank movement and blow-by gas, but the breather valve 43 (check valve) (which acts to pass only positive pressure), the positive pressure part is cut,
It shows pulsation where the average is negative pressure.

Note that the positive pressure caused by the blow-by gas from the breather subchamber 62 is not sucked into the air cleaner side, but is released to the atmosphere through the breather pipe 49 and the air cleaner 50.

The pressure inside the breather sub-chamber 62 is communicated with the atmosphere by the air cleaner 50, and the blow-by gas passes therethrough, so the pressure in the sub-breather chamber 62 becomes slightly positive, but is maintained at approximately atmospheric pressure.

In the above case, when the crank chamber C becomes negative pressure, the differential pressure with the breather main chamber 61 opens the check valve (consisting of the small hole 45, the ball 56, and the spring 57), and the oil flows into the crank chamber. Return to C.

In cases other than the above, the elastic force of the spring 57 pushes the ball 56 into the small hole 45.
When pressed against the opening, the check valve is closed.

In FIG. 7, a check valve (ball 56, spring 57) is provided, so if there is a pressure difference between the breather main chamber 61 and the crank chamber C, it can be improved.

Furthermore, the ones shown in Figs. 8 and 9 are further improved versions of those shown in Fig. 7, and actively lubricate due to the pressure difference between the breather subchamber 62 (atmospheric pressure) and the crank chamber C (negative pressure). (Fig. 9) and a check valve (ball 56, spring 57) (Fig. 8) will increase the effect and prevent the oil splashed up by the oil scraper from directly entering the breather subchamber 62. It also has the effect of preventing

Furthermore, the one shown in FIG. 7 may be attached to the one shown in FIG. 8 or 9.

Although FIG. 3 shows an OHV (overhead valve) type engine, the present invention can also be applied to an SV (side valve) type engine.

Further, although FIG. 8 shows a valve composed of a ball and a spring, a plate valve may also be used.

As described above, in the case of the present invention, the oil can be returned smoothly, so that the problems of the conventional ones are solved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the main parts of an engine equipped with a conventional breather device, Fig. 2 is a sectional view taken along the ■-■ arrow in Fig. 1, and Fig. 3 is a sectional view showing the main parts of an engine equipped with a conventional breather device. 4 is a cross-sectional view taken along the line A-A in Figure 3, Figure 5 is a cross-sectional view taken along the line B-B in Figure 3, and Figure 6 is a conventional breather chamber. FIG. 7 is an explanatory diagram showing the oil return device of
FIG. 8 is an explanatory diagram showing the oil return device for the breather chamber according to the second embodiment of the present invention. FIG. 9 is an explanatory diagram showing the oil return device for the breather chamber according to the third embodiment of the present invention. It is an explanatory view showing an oil return device of a room. 31... Crank case, 41... Breather chamber, 42... Lid, 43... Breather valve, 44... Breather plate, 45 ...
... Oil return hole, 56 ... Ball, 57 ...
... Spring, 61 ... Breather main chamber, 62.
...breather side room.

Claims (1)

[Scope of utility model registration request] The breather chamber is divided into a main breather chamber connected to a rocker chamber communicated with the crank chamber and a sub-breather chamber connected to an air cleaner via a breather valve that allows fluid to flow only from the main chamber to the sub-chamber. In a breather device for an internal combustion engine, a communication passage is provided that communicates either one or both of the breather main chamber or the breather sub-chamber with the crank chamber, and the communication passage between the breather main chamber and the crank chamber is provided with the above-mentioned A breather device for an internal combustion engine, comprising a check valve that only allows fluid to flow from a main breather chamber to a crank chamber.