JP3823629B2 - Crankcase breather chamber structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a crankcase breather chamber structure for oil separation (gas-liquid separation) in blow-by gas of a four-cycle engine.
[0002]
[Prior art]
Conventionally, in a four-cycle engine, in order to return blow-by gas generated in the crankcase from the sliding portion between the cylinder inner peripheral surface and the piston when the engine is driven, A blow-by gas passage is formed, and blow-by gas is fed into an engine intake system such as an air cleaner using the negative pressure of the intake manifold.
[0003]
As a conventional example, as shown in FIG. 7, a gas vent hole 3 for communicating the crankcase 1 and the breather chamber 2 is formed in a breather chamber 2 formed in the vicinity of the crankcase 1. There is known one in which blow-by gas is returned to an intake path (not shown).
[0004]
[Problems to be solved by the invention]
However, a gear (not shown) is formed in the vicinity of the vent hole 3 and a part of the gear is below the oil level of the engine oil 4, so that the engine oil is scattered by the driving of the gear. The blow-by gas in which the oil mist is mixed is introduced into the air cleaner (not shown) through the connection pipe 7 through the opening 6 of the breather chamber 5 without separating the oil mist from the breather chamber 2. This method has a problem in that when the oil mist is contained in the blow-by gas, the engine is adversely affected. On the other hand, as disclosed in Japanese Utility Model Laid-Open No. 5-83310, a so-called oil separator is provided in which a plurality of interference bodies are provided in the head cover to separate the oil mist while interfering with the flow of blow-by gas. However, there has been a problem that the configuration of the head cover becomes complicated and cannot be made compact.
[0005]
The present invention has been made in view of the above-mentioned conventional problems, and it is possible to easily separate oil mist from blow-by gas with a simple configuration without greatly changing the external dimensions of the engine. The purpose is to provide a structure.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration. The present invention is, adjacent to the crank chamber in the crankcase of the engine, and to form a separate breather chamber and the crank case, V belt transmission for clutch and Kakarido provided on the crank shaft end housing The breather chamber is disposed between the V-belt transmission chamber and the separation wall between the crank chamber and the breather chamber is connected to the crank chamber and the breather chamber under the lubricating oil surface. while Ru is provided a mouth communicating with said breather chamber and the crank chamber on the lubricating oil level, and is provided with a tubular member having an opening formed to project the breather chamber side wall surface being directed in the lubricating oil level Further, it is characterized in that a route communication means for communicating the breather chamber and the intake system route is provided.
[0007]
The breather chamber is preferably disposed between the clutch and the driven V-belt transmission .
[0008]
The breather chamber is preferably formed by the crankcase and a clutch cover for covering a clutch provided at the end of the crankshaft.
[0009]
Furthermore, it is preferable that the breather chamber side opening of the tubular member is formed adjacent to and opposed to the wall surface of the breather chamber .
[0010]
According to the present invention, a breather chamber that is adjacent to and separated from a crank chamber in the crankcase of the engine is formed, and the crank wall and the breather chamber are separated from each other under the lubricating oil surface. A communication port for communicating the chamber and the breather chamber, communicating the crank chamber and the breather chamber on the lubricating oil surface, and the breather chamber side wall surface with the opening facing the lubricating oil surface And a passage communicating means for communicating the breather chamber with the intake system passage, so that the blow-by can be performed with a simple configuration without greatly changing the external dimensions of the engine. Oil mist can be easily separated from the gas.
[0011]
In addition, by forming the breather chamber side opening of the tubular member adjacent to and facing the wall surface of the breather chamber, the blow-by gas is blown directly onto the wall surface as well as the lubricating oil surface. Oil mist can be easily separated.
[0012]
Further, the breather chamber can be formed with a simple configuration and without greatly changing the external dimensions of the engine, compared to the case where the breather chamber is formed by the crankcase and a clutch cover for covering the clutch provided at the crankshaft end. it can.
[0013]
Further, the breather chamber is formed between a crankcase that houses the reduction gear and a V-belt transmission chamber that houses a V-belt transmission that is engaged with a clutch provided at the end of the crankshaft. The breather chamber can be configured without greatly changing the external dimensions of the engine.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
As shown in FIGS. 1 and 2, the present embodiment forms a breather chamber 12 adjacent to and separated from a crank chamber 11 in the crankcase 10 of the engine, and the crank chamber 11 and the breather chamber 12. Is provided with a communication port 15 for communicating the crank chamber 11 and the breather chamber 12 below the level of the engine oil 14, and the crank chamber 11 and the breather chamber above the level of the engine oil 14. 12 and a tubular communication pipe 18 projecting from the side wall surface 17 of the breather chamber 12 with the opening 16 facing the oil level of the engine oil 14, and the breather chamber 12 and the intake system path ( It is a crankcase breather chamber structure provided with the connection pipe 19 which is a path | route communication means for connecting (not shown).
[0016]
As shown in FIG. 1, the breather chamber 12 is formed so as to be surrounded by a separation wall portion 13 of the crankcase 10 and a clutch cover 21 for covering the clutch 20 provided at the crankshaft end. . A V-belt transmission chamber 24 in which the V-belt transmissions 22 and 23 are accommodated is formed outside the clutch cover 21. Further, as shown in FIG. 2, the breather chamber 12 is formed with an intake system path communication port 25 communicating with another breather chamber (not shown) formed on the back surface of the breather chamber 12. Accordingly, the intake pipe is communicated with the intake system path via the connection pipe 19. The breather chamber 12 is divided into two chambers by ribs 26 as shown in FIG. The rib 26 is formed with a notch 27 in the width direction extending in the longitudinal direction, and communicates the internal space of the breather chamber 12 divided into two chambers via the notch 27.
[0017]
As shown in FIGS. 1 and 4, the communication pipe 18 has a substantially cylindrical shape, is disposed through the separation wall portion 13 between the crank chamber 11 and the breather chamber 12, and is separated via a fixing stay 28. The wall portion 13 is fixed with bolts 29. The opening 16 on the breather chamber 12 side of the communication pipe 18 is close to the separation wall portion 30 on the clutch cover side, and is substantially opposed to both the separation wall portion 30 and the engine oil 14 liquid surface. The cross section is formed obliquely at an angle of 45 degrees.
[0018]
Next, the operation of the crankcase breather chamber structure configured as described above will be described.
[0019]
First, as shown in FIG. 4, blow-by gas generated in the crank chamber 11 by driving the engine flows into the breather chamber 12 through the communication pipe 18. At this time, the flow direction of the blow-by gas is controlled by the opening direction of the communication pipe 18, a part is blown toward the separation wall portion 30, and a part is blown to the engine oil 14 liquid level. At this time, the oil mist in the blow-by gas collides with the separation wall portion 30 to become liquid and travels down the separation wall portion 30 and is reduced to an oil pan (not shown). It is sprayed and reduced to oil.
[0020]
Next, this blow-by gas flows into the breather chamber 31 in the crankcase through the intake system passage communication port 27, and further from the communication pipe 19 through a connection hose (not shown) to an air cleaner (not shown). ) And supplied to the intake system path.
[0021]
In this way, by separating the oil mist in the blow-by gas, it becomes possible to supply blow-by gas having a low oil mist content. Therefore, the recovery rate of the engine oil can be improved, and the air cleaner Dirt can be reduced.
[0022]
The present invention is not limited to the above embodiment, and the breather chamber side opening of the communication pipe 32 is formed to face the engine oil 14 liquid level as in the second embodiment shown in FIG. Alternatively, the blow-by gas may be directly blown onto the engine oil 14, and according to this, the oil mist can be easily separated from the blow-by gas with a simple configuration.
[0023]
Further, as in the third embodiment shown in FIG. 6, the breather chamber side opening portion of the communication pipe 33 is integrally connected to the fixing stay 34 and is formed so as to face the engine oil 14 liquid level. The gas may be blown to both the surface 35 facing the communication pipe 33 and the engine oil 14. According to this, the communication pipe 33 is not formed to the vicinity of the separation wall surface of the clutch cover. Oil mist can be easily separated from blow-by gas with a compact configuration.
[0024]
【The invention's effect】
As described above, according to the present invention, the breather chamber is formed adjacent to the crank chamber, and the communication pipe is formed in the breather chamber so that the blow-by gas is blown directly onto the wall surface of the breather chamber and the engine oil level. Thus, there is an effect that the oil mist can be easily separated with a simple configuration. Further, the breather chamber is surrounded by the separation wall of the crankcase and the separation wall of the clutch cover between the crankcase and the V-belt transmission chamber, so that the breather chamber can be formed without greatly changing the outer dimensions of the engine. There is an effect that it can be formed. Further, since the oil mist can be separated from the blow-by gas without providing an oil mist separator separately, there is an effect that the structure of the engine can be simplified.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a crankcase breather chamber structure according to an embodiment of the present invention.
FIG. 2 is a side view of a crankcase breather chamber structure according to an embodiment of the present invention.
FIG. 3 is an explanatory view on the clutch cover side of the crankcase breather chamber structure according to the embodiment of the present invention.
FIG. 4 is a detailed cross-sectional view of a crankcase breather chamber structure according to an embodiment of the present invention.
FIG. 5 is a detailed cross-sectional view of a crankcase breather chamber structure according to Embodiment 2 of the present invention.
FIG. 6 is a detailed sectional view of a crankcase breather chamber structure according to Embodiment 3 of the present invention.
FIG. 7 is an explanatory view showing a configuration of a conventional crankcase.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Crankcase 2 Breather chamber 3 Gas vent hole 4 Engine oil 5 Breather chamber 6 Opening part 7 Connection pipe 10 Crankcase 11 Crank chamber 12 Breather chamber 13 Separation wall part 14 Engine oil 15 Communication port 16 Opening part 17 Wall surface 18 Communication pipe 19 Connection pipe 20 Clutch 21 Clutch cover 22 V-belt transmission 23 V-belt transmission 24 V-belt transmission chamber 24a V-belt transmission cover 25 Intake system path communication port 26 Rib 27 Notch 28 Fixing stay 29 Bolt 30 Separation wall Part 31 breather chamber 32 communication pipe 33 communication pipe 34 fixing stay 35 opposite surface

Claims (4)

A V-belt adjacent to a crank chamber in an engine crankcase and forming a separated breather chamber and housing a V-belt transmission that engages with the crankcase and a clutch provided at the end of the crankshaft. The breather chamber is disposed between the transmission chamber and the transmission chamber,
The separation wall between the crank chamber and the breather chamber, while Ru provided passage for communicating with said crank chamber and the breather chamber under lubricating oil level, the crank chamber and the breather chamber on the lubricating oil level And a passage communicating means for communicating the breather chamber and the intake system passage by providing a tubular member projectingly formed on the side wall surface of the breather chamber with the opening portion facing the lubricating oil surface. Crankcase breather chamber structure characterized by comprising. 2. The crankcase breather chamber structure according to claim 1, wherein the breather chamber is disposed between the clutch and a driven V-belt transmission . The crankcase breather chamber structure according to claim 1 or 2, wherein the breather chamber is formed by the crankcase and a clutch cover for covering a clutch provided at a crankshaft end. The crankcase breather chamber structure according to any one of claims 1 to 3 , wherein the breather chamber side opening of the tubular member is formed adjacent to and opposite to a breather chamber wall surface .

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