JPH0882209A - Breather device for overhead valve engine - Google Patents

Abstract

(57) [Summary] [Purpose] Even when the oil is excessively stored in the oil pan, the oil is smoothly returned to the oil pan from the blow-by gas guide passage. [Structure] The blow-by gas guide bypass passage 15 derived from the gear chamber 12 is communicated with the rocker arm chamber 5, and the outlet 16 of the blow-by gas guide bypass passage 15 is located higher than the outlet 10 of the blow-by gas guide passage 8 in the rocker arm chamber 5.
To face. The gas in the crank chamber 7 is passed through the bypass 15
Since it is dispersed into the breather device 6 and guided to the breather device 6, the flow rate of the gas blown up in the blowby gas guide passage 8 is reduced, and the oil in the rocker arm chamber 5 smoothly flows down the blowby gas guide passage 8 and is returned to the oil pan 21. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breather device for an overhead valve engine. Even when the oil is excessively stored in an oil pan, the oil is smoothly returned from the blow-by gas guide passage to the oil pan, and the oil from the breather device is removed. Provide products that can effectively prevent discharge.

[0002]

BACKGROUND OF THE INVENTION The basic structure of the breather device for an overhead valve engine, which is the subject of the present invention, is as shown in FIG. 1 or FIG.
Gear case 2 on one side of crankcase 1 of engine E
Is provided, the head cover 3 is provided above the cylinder head 4, the breather device 6 is provided in the rocker arm chamber 5 of the head cover 3, and the blow-by gas guide passage 8 is provided from the crank chamber 7.
To communicate with the rocker arm chamber 5 to guide blow-by gas from the crank chamber 7 to the blow-by gas guide passage 8.
From the outlet 10 of the blow-by gas guide passage 8 through the rocker arm chamber 5 to the breather inlet 11 of the breather device 6,
The breather device 6 is configured so that it can be discharged to the outside from the breather outlet 13 and the gear chamber 12 of the gear case 2 is connected to the oil return passage 1
It is of a type that communicates with the crank chamber 7 via 4.
The oil return passage 14 is for returning the excess oil in the gear chamber 12 to the oil pan via the crank chamber 7.

[0003]

2. Description of the Related Art As a conventional technique of this type, as shown in FIG. 3, a ventilation passage 17 is opened from a crank chamber 7 of a vertical overhead valve engine E to a tappet chamber 19, and a tappet chamber 19 is extended to a rocker arm chamber 5. Push rod fitting slot 1
The blow-by gas guide passage 8 is configured by 8 and the ventilation passage 17, and the blow-by gas blown from the combustion chamber into the crank chamber 7 is guided to the breather device 6 through the blow-by gas guide passage 8 and the breather device 6 is provided. There is a configuration in which the oil separated in step 1 is returned from the blow-by gas guide passage 8 to the oil pan 21 via the crank chamber 7.

[0004]

In the above-mentioned prior art, when the oil is excessively filled in the oil pan 21, foaming is severe due to the crank shaft 22 scratching the oil surface. A large amount of bubbles and blow-by gas together flow into the breather device 6 from the blow-by gas guide passage 8 through the rocker arm chamber 5.

Therefore, normally, the oil separated by the breather device 6 flows down from the rocker arm chamber 5 through the blow-by gas guide passage 8 and is returned to the oil pan 21, but passes through the blow-by gas guide passage 8 and returns to the rocker arm chamber 5. Since the flow rate of the gas blown up to is increased, the oil to be recirculated cannot be returned due to the resistance to blow up the gas, and is discharged from the breather outlet 13 of the breather device 6 to the outside. In this case, the method of releasing the blow-by gas into the atmosphere may pollute the atmosphere, and the method of returning the blow-by gas to the intake passage 23 may cause the engine to overrun. The present invention
A technical problem is to smoothly return the oil from the blow-by gas guide path to the oil pan even when the oil is excessively stored in the oil pan.

[0006]

Means for achieving the above object will be described below with reference to FIGS. 1 and 2 showing an embodiment. That is, according to the present invention, in the breather device for an overhead valve engine having the basic structure, the blow-by gas guiding bypass passage 15 derived from the gear chamber 12 is communicated with the rocker arm chamber 5, and the outlet 16 of the blow-by gas guiding bypass passage 15 is connected. Is exposed to the rocker arm chamber 5 at a position higher than the exit 10 of the blow-by gas guide passage 8. The blow-by gas is discharged to the outside from the breather outlet 13 of the breather device 6, and the outside means the atmosphere or the intake passage of the engine.

[0007]

When the oil is excessively stored in the oil pan 21, the bubbles of the oil filling the crank chamber 7 and the blow-by gas are combined together to flow into the breather device 6 through the blow-by gas guide passage 8 in a large amount. To do. However, in the present invention, since the gear chamber 12 and the rocker arm chamber 5 are communicated with each other by the blow-by gas guide bypass passage 15, a part of a large amount of gas generated in the crank chamber 6 is partially removed from the oil return passage 1.
4 (that is, the direction in which the excess oil in the gear chamber 12 returns) enters the gear chamber 12 and is guided to the rocker arm chamber 5 via the bypass passage 15.

Therefore, when the engine E is operating, the flow rate of gas blown up from the crank chamber 7 to the blow-by gas guide path 8 is reduced by the flow rate of gas blown through the bypass passage 15. Therefore, the oil in the rocker arm chamber 5 smoothly flows down the blow-by gas guide passage 8,
It is returned from the crank chamber 7 to the oil pan 21.

The blow-by gas guide bypass passage 15 is provided.
The outlet 16 of the blow-by gas guide passage 8 is exposed to the rocker arm chamber 5 at a position higher than the outlet 10 of the blow-by gas guide passage 8.
On the contrary, it does not flow down to the gear chamber 12 side, and does not become a flow resistance of the blow-by gas passing through the bypass passage 15.

[0010]

Since the gas generated in the crank chamber is dispersed in the bypass passage and guided to the breather device, the flow rate of the gas blown up in the blow-by gas guide passage is reduced, and the oil in the rocker arm chamber smoothly flows down the blow-by gas guide passage. Then it is returned to the oil pan. For this reason, oil is not discharged to the outside from the breather outlet of the breather device, and air pollution and engine overrun can be effectively prevented.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a right side view of a vertical section of a breather device of a vertical overhead valve diesel engine, and FIG. 2 is a front view of the overhead valve engine.

As shown in FIGS. 1 and 2, a gear case 2 is fixed to the front side of a crankcase 1 of a vertical overhead valve engine E, a head cover 3 is fixed above a cylinder head 4, and a rocker arm chamber of the head cover 3 is fixed. The breather device 6 is arranged on the upper part of 5 in a protruding manner. The breather device 6
Is the breather inlet 11 opened at the bottom of the breather chamber 24.
And an oil separating agent 25 such as glass wool filled in the breather chamber 24 and a breather outlet 13 opened at an upper side of the breather chamber 24. The breather inlet 11 communicates with the rocker arm chamber 5 and the breather outlet 1
3 is communicated with the intake passage 23 of the engine E through the return pipe 26.

As shown in FIG. 2, the overhead valve engine E is
The ventilation passage 17 is opened from the crank chamber 7 to the tappet chamber 19, and the blow-by gas guide passage 8 is constituted by the push rod fitting insertion opening 18 penetrating upward from the tappet chamber 19 and the ventilation passage 17, and The outlet 10 of the gas guide passage 8 communicates with the rocker arm chamber 5. Then, the blow-by gas blown from the combustion chamber 27 into the crank chamber 7 is guided to the breather device 6 through the blow-by gas guide passage 8, and the return pipe 26 is discharged from the breather outlet 13.
The oil separated by the breather device 6 is flowed down from the blow-by gas guide path 8 into the crank chamber 7 and returned to the oil pan 21.

As shown in FIG. 1, a crank gear 28, an idle gear 29, an oil pump gear 31, and the like are housed in the gear chamber 12 of the gear case 2, and the lower portion of the gear chamber 12 and the crank chamber 7 are connected to an oil return path. 14, the excess oil in the gear chamber 12 flows into the crank chamber 7,
It is configured to return to the oil pan 21. The gear chamber 12
The blow-by gas guiding bypass pipe 15 is led out from the upper part of the above, and the outlet 16 of the blow-by gas guiding bypass pipe 15 is communicated with the rocker arm chamber 5. In this case, as shown in FIGS. 1 and 2, the outlet 16 of the blow-by gas guide bypass passage 15 faces the rocker arm chamber 5 at a position higher than the outlet 10 of the blow-by gas guide passage 8.

The function of the breather device for the vertical overhead valve engine of this embodiment will be described. When the oil is excessively stored in the oil pan 21, foaming becomes severe due to the oil surface being scratched by the crankshaft 22. Therefore, the bubbles of the oil filling the crank chamber 7 and the blowby gas are combined together to produce a large amount of the blowby gas. An attempt is made to flow into the breather device 6 through the guide passage 8. However, in this embodiment, since the blow-by gas guiding bypass pipe 15 is connected from the gear chamber 12 to the rocker arm chamber 5, the crank chamber 6
A part of a large amount of gas generated in the above enters the gear chamber 12 through the oil return passage 14 and is guided to the rocker arm chamber 5 via the blow-by gas guiding bypass pipe 15.

Therefore, when the engine E is operating, the flow rate of gas blown up from the crank chamber 7 to the blow-by gas guide passage 8 is reduced by the flow rate of the gas guided by the blow-by gas guide bypass pipe 15. Therefore, the oil in the rocker arm chamber 5 flows down the blow-by gas guide passage 8 and is smoothly returned from the crank chamber 7 to the oil pan 21, so that the oil is not discharged from the breather outlet 13 of the breather device 6. That is, the oil does not flow back to the intake passage 23 via the reduction pipe 26,
The overrun of the engine E can be effectively prevented.

The blow-by gas guide bypass pipe 1 is also provided.
Since the outlet 16 of the rocker arm chamber 5 is set higher than the outlet 10 of the blow-by gas guide passage 8, the oil in the rocker arm chamber 5 flows from the blow-by gas guide bypass pipe 15 to the gear chamber 1
2 does not flow down, and the bypass pipe 15
There is no hindrance to blow-by gas blow-through.

In the present invention, the blow-by gas guiding bypass passage 15 connecting the gear chamber 12 and the rocker arm chamber 5 is
Instead of connecting with an external pipe as in the above embodiment,
There is no problem even if they are communicated with each other through a bypass hole that penetrates the meat wall of the engine E. Further, the present invention is not limited to the diesel engine as in the above embodiment, but can be applied to a spark ignition engine.

[Brief description of drawings]

FIG. 1 is a right side view in vertical section of a main part of a breather device for a vertical overhead valve diesel engine.

FIG. 2 is a front view of the overhead valve engine.

FIG. 3 is a view corresponding to FIG. 2 showing a conventional technique.

[Explanation of symbols]

1 ... Crank case, 2 ... Gear case, 3 ... Head cover, 4 ... Cylinder head, 5 ... Rocker arm chamber, 6 ... Breather device, 7 ... Crank chamber, 8 ... Blow-by gas guide passage, 10 ... Blow-by gas guide passage outlet, 11 ... breather inlet, 12 ... gear chamber, 13 ... breather outlet, 14 ... oil return passage, 15 ... blow-by gas guide bypass passage,
16 ... Exit of the bypass, E ... Engine.

Claims (1)

[Claims] 1. A gear case (2) is provided on one side of a crank case (1) of an engine (E), a head cover (3) is provided above a cylinder head (4), and a rocker arm chamber (3) of the head cover (3) is provided. The breather device (6) is arranged in (5), the blow-by gas guide path (8) is led out from the crank chamber (7) and communicates with the rocker arm chamber (5), and blow-by gas is fed into the crank chamber.
From (7) to the blow-by gas guide path (8), and from the exit (10) of the blow-by gas guide path (8) to the rocker arm chamber (5)
Through the breather device (6) to the breather inlet (11) of the breather device (6) so that it can be discharged to the outside from the breather outlet (13) of the breather device (6), and the gear chamber (12) of the gear case (2) is returned to oil. In a breather device for an overhead valve engine that communicates with a crank chamber (7) through a passage (14), a blow-by gas guiding bypass passage (15) derived from the gear chamber (12) is communicated with a rocker arm chamber (5). , The outlet (1) of the blow-by gas guide bypass passage (15)
A breather device for an overhead valve engine, characterized in that (6) faces the rocker arm chamber (5) at a position higher than the exit (10) of the blow-by gas guide passage (8).