JP2014196710A - Breather device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To integrally mold a cylinder block at a peripheral wall of a breather device (30) arranged at a trough of a V-shaped bank of an internal combustion engine which has a crank case (2), fore-and-aft cylinder blocks (3F, 3R) which are integrally connected to the crank case (2), and arranged so as to mutually constitute the V-shaped bank, and a plurality of cylinders (4) which are arranged at the respective cylinder blocks, and paired in fore-and-aft directions.SOLUTION: A breathing gas discharge cylinder attachment hole (36) for attaching a breathing gas discharge cylinder (35) which connects hoses for discharging gases from a breathing chamber (31) is formed at a ceiling wall (33) of the breathing chamber (31), and core sand for forming the breathing chamber (31) at forging is removed from the breathing gas discharge cylinder attachment hole (36). Therefore, cylinder blocks (3F, 3R) can be integrally molded at a wall of the surroundings of a breather device (30).

Description

  The present invention relates to a breather apparatus.

  Conventionally, a breather device is integrally formed between V-shaped cylinder blocks of a V-type internal combustion engine. In this breather device, a breather chamber inlet hole communicating with the inside of the crankcase and an oil discharge hole for returning separated oil to the oil pan are provided in any of the peripheral walls constituting the internal breather chamber. These breather chamber inlet holes and oil discharge holes need to prevent direct oil inflow from the crankcase, and are designed to have shapes and positions that make it difficult for oil to enter. It was. For this reason, in the prior art, a part of the peripheral wall is formed separately. In consideration of the reduction in the number of parts of the internal combustion engine, the demand for reduction in size and weight, and workability in the assembly line, it has been desired that all the peripheral walls of the breather chamber are integrally formed with the internal combustion engine.

Japanese Patent Laid-Open No. 9-209738 (FIG. 2)

  The present invention is intended to provide a breather device in which a breather chamber is completely integrated with a crankcase.

The present invention solves the above problems, and the invention according to claim 1
A crankcase (2), and front and rear cylinder blocks (3F, 3R) integrally connected to the crankcase (2) and arranged to form a V-shaped bank,
A plurality of front and rear cylinder blocks (3F, 3R) each provided with a plurality of cylinders (4) paired in front and rear;
Pistons (12) respectively accommodated in the cylinders (4);
An internal combustion engine (1) having a crankshaft (10) supported by the crankcase (2) and rotating in response to sliding of the piston (12),
In the breather device (30) provided in the valley of the V-shaped bank and communicating with the inside of the crankcase (2),
A bottom wall (32) integrally formed by sharing the lower ends of the plurality of cylinders (4) forming the V shape;
A ceiling wall (33) located above the bottom wall (32) and integrally formed across the plurality of V-shaped cylinder blocks (3F, 3R);
Side walls (34) forming a breather chamber (31) of the breather device (30) by closing both ends in the direction of the crankshaft (10) between the V-shaped cylinder blocks (3F, 3R). )When,
A breather chamber inlet hole (43) provided on at least one of the side walls (34) and communicating with the crankcase;
In addition, the breathing gas discharge cylinder (35) for connecting a hose for discharging gas from the breather chamber (31) is attached to the breathing gas discharge cylinder mounting hole (36) provided in the ceiling wall (33). The breather apparatus (30) is characterized.

The invention according to claim 2 is the breather device (30) according to claim 1,
Apart from the breathing gas discharge tube mounting hole (36), it has a through hole (38) for taking out the core formed in the ceiling wall (33),
Each core take-out through hole (38) is fitted with a closing plug (39) to be closed.

The invention according to claim 3 is the breather device (30) according to claim 1 or 2,
An inlet barrier (46) is erected in the breather device (30) so as to overlap a part of the breather chamber inlet hole (43).

The invention according to claim 4 is the breather device (30) according to any one of claims 1 to 3,
Of the side wall (34), an oil discharge hole (44) for discharging oil accumulated in the breather device (30) is provided on the side wall (34) opposite to the side where the breather chamber inlet hole (43) is provided. It is provided.

The invention according to claim 5 is the breather device (30) according to any one of claims 1 to 4,
On the top surface of the ceiling wall (33), a drainage groove (23) is formed which is recessed inward of the breather device (30) and extends in the direction of the crankshaft (10).

The invention described in claim 6 is the breather device (30) according to claim 5,
The drainage groove (23) on the upper surface of the ceiling wall (33) is formed to be gradually deeper toward one side in the direction of the crankshaft (10), and a drain hole (24) is provided on the end side wall. To do.

The invention according to claim 7 is the breather device (50) according to any one of claims 1 to 6,
A gas outlet barrier (66) is formed below the breathing gas discharge tube mounting hole (54) to which the breathing gas discharge tube (53) is mounted.

The invention according to claim 8 is the breather device (50) according to claim 7,
A cavity (62) extending around the breather chamber (61) is formed below the breathing gas discharge tube mounting hole (54) and above the gas outlet barrier (66). The breathing gas discharge tube (53) is attached so that the lower extension (60) of the breathing gas discharge tube (53) enters.

  In the invention of claim 1, the wall surrounding the periphery of the breather device (30) provided between the cylinders (4) of the V-type internal combustion engine (1) is formed integrally with the cylinder block (3F, 3R), and the ceiling wall ( 33) and the breathing gas discharge tube mounting hole (36) for mounting the breathing gas discharge tube (35) is formed, so the breather chamber (31) is formed when forming the breather device (30) by molding with a mold. Since the core for this purpose can be removed from the breathing gas discharge tube mounting hole (36), the wall around the breather device (30) can be integrally formed with the cylinder block (3F, 3R). As a result, the breather chamber (31) can be reduced in size while securing the breather capacity, and the number of parts of the internal combustion engine can be reduced and the assembly workability can be improved.

  In the invention of claim 2, the ceiling wall (33) is provided with a core take-out through hole (38) in addition to the breathing gas discharge tube mounting hole (36), and a closing plug (39) is fitted into the breather, thereby providing a breather. While being established as a device (30), it is possible to increase the number of extraction holes of the core during manufacture, facilitating removal, so that it is possible to integrally form a complex breather chamber (31) in the crankcase (2) with a mold. it can.

  In the invention of claim 3, the oil can flow directly from the crankcase (2) by standing the inlet barrier (46) in the breather device (30) facing the breather chamber inlet hole (43). Can be suppressed.

  In the invention of claim 4, by providing the oil discharge hole (44) on the side wall (34) opposite to the breather chamber inlet hole (43), the gas flowing from the breather chamber inlet hole (43) The oil can be discharged well without being hindered.

  In the invention of claim 5, water accumulated on the upper surface of the breather device (30) can be discharged through the drainage groove (23) on the upper surface of the ceiling wall (33).

  In the invention of claim 6, water collected on the upper surface of the ceiling wall (33) can be collected and discharged more satisfactorily.

  In the invention of claim 7, by forming the gas outlet barrier (66) below the breathing gas discharge tube mounting hole (54), a labyrinth structure in the breather device (50) is formed to improve gas-liquid separation performance. Can be improved.

  8. The lower extension (60) of the breathing gas discharge tube (53) in the cavity (62) below the breathing gas discharge tube mounting hole (54) and above the gas outlet barrier (66). The labyrinth structure can be formed by rushing in and the gas-liquid separation performance can be improved.

1 is a left side view of a DOHC type V-type four-cylinder four-cycle internal combustion engine for mounting on a motorcycle according to an embodiment of the present invention. It is a principal part expanded sectional left view of the said internal combustion engine. It is the figure which looked at the vicinity of the breather device of the above-mentioned internal-combustion engine from the upper right diagonal of the internal-combustion engine. It is the figure which looked at the vicinity of the breather device of the above-mentioned internal combustion engine from the upper part of the internal combustion engine. It is VV sectional drawing of FIG. It is VI-VI sectional drawing of FIG.2 and FIG.4. It is the figure which looked at the upper surface of the breather device concerning a 2nd embodiment of the present invention from the upper right diagonal of an internal-combustion engine. It is VIII-VIII sectional drawing of FIG. It is IX-IX sectional drawing of FIG.

  FIG. 1 is a left side view of a DOHC type V-type four-cylinder four-cycle internal combustion engine 1 for mounting on a motorcycle according to an embodiment of the present invention. Arrow F indicates the front when the vehicle is mounted, and arrow Rear indicates the rear. A crankcase 2 occupies the central portion of the internal combustion engine 1. The crankcase 2 includes an upper crankcase 2A and a lower crankcase 2B. The upper crankcase 2A includes a front cylinder block 3F and a rear cylinder block 3R that are integrally formed. The front cylinder block 3F and the rear cylinder block 3R each include two cylinders 4. The center line of the front cylinder block 3F and the center line of the rear cylinder block 3R are perpendicular to each other. A cylinder head 5 is fastened to the upper end surfaces of the front cylinder block 3F and the rear cylinder block 3R, and a cylinder head cover 6 is fastened to the upper end surfaces of the cylinder heads 5. An upper end surface of the lower crankcase 2B is fastened to a lower end surface of the upper crankcase 2A, and an integral crankcase 2 is formed. Inside the cylinder head 5 and the cylinder head cover 6, a valve operating mechanism 7 and a spark plug 8 are provided corresponding to each cylinder 4.

  A crank chamber 9 is formed in the front half of the crankcase 2. The crankshaft 10 oriented in the left-right direction of the vehicle body is rotatably supported with the rotation axis positioned on the mating surfaces of the upper and lower crankcases 2A, 2B. The crankshaft 10 is provided with two left and right crankpins 11. Two pistons 12 on the front side and two on the rear side are connected to the crankpin 11 via connecting rods 13, respectively.

  The rear half of the crankcase 2 is a transmission chamber 14 in which a constantly meshing gear transmission 15 is accommodated. An oil pan 16 is fastened to the lower end surface of the lower crankcase 2B. An oil pump 17 and the like are provided below the lower crankcase 2B, and lubricating oil is supplied to each part of the internal combustion engine 1.

  FIG. 2 is an enlarged cross-sectional left side view of the main part of the internal combustion engine 1. Pistons 12 are slidably fitted to the front and rear cylinders 4 respectively. A crankshaft 10 is rotatably supported on a mating surface between the upper crankcase 2A and the lower crankcase 2B. Both ends of a connecting rod 13 are pivotally attached to the crankpin 11 and the piston 12, and the crankshaft 10 is rotationally driven in response to the vertical movement of the piston 12.

  An intake port 18 is disposed on the side where the lower portions of the front and rear cylinder heads 5 are close to each other, and an exhaust port 19 is disposed on each of the front and rear outer sides of the front and rear cylinder heads 5. A throttle body connecting member 20 is provided above the intake port 18. An intake valve 21 is provided at the intake port 18, and an exhaust valve 22 is provided at the exhaust port 19 so as to be freely opened and closed. A spark plug 8 is provided at a position sandwiched between the intake valve 21 and the exhaust valve 22.

  A breather device 30 is provided in a valley portion of the V-shaped bank sandwiched between the front and rear cylinder blocks 3F and 3R and in a portion located on the upper surface of the crankcase 2. A breather chamber 31 is formed inside. The peripheral wall except the ceiling wall 33 of the breather chamber 31 is formed in common with the front and rear cylinder blocks 3F and 3R and a part of the upper crankcase 2A.

  In other words, the bottom wall 32 integrally formed by sharing the lower ends of the plurality of V-shaped cylinders 4 is formed integrally over the plurality of V-shaped cylinders above the bottom wall 32. Side walls 34 (FIGS. 5 and 6) that form the breather chamber 31 are formed by closing both ends of the ceiling wall 33 and the V-shaped cylinders 4 in the direction of the crankshaft 10. .

  FIG. 3 is a view of the upper surface of the breather device 30 of the internal combustion engine 1 as viewed from the upper right side of the internal combustion engine 1. In the following drawings, the arrow L indicates the left side of the internal combustion engine 1 when mounted on the vehicle, and the arrow R indicates the right side. Each of the front cylinder block 3F and the rear cylinder block 3R has two cylinders 4, and the total number of cylinders is four. Four intake ports 18 are provided corresponding to each cylinder 4. A throttle body connecting member 20 that is wide open is provided above each intake port 18.

  A drainage groove 23 is formed on the upper surface of the ceiling wall 33 of the breather device 30. The drainage groove 23 is formed deeper gradually toward one side in the direction of the crankshaft 10. A drain hole 24 is provided at the end of the drainage groove 23, and rainwater poured on the upper surface of the internal combustion engine 1 is discharged. Rainwater flows out along the arrow. A breathing gas discharge cylinder 35 of a breather device 30 that opens upward adjacent to the drain groove 23 is provided. The breathing gas discharge cylinder 35 is attached to a breathing gas discharge cylinder attachment hole 36 provided in the ceiling wall. The breathing gas discharge cylinder 35 is a cylinder for sending unburned gas separated by the breather device 30 toward an air cleaner (not shown) via a hose (not shown). The sent unburned gas is supplied again to the internal combustion engine 1 together with air and burned. The hose is connected to the upper part of the breathing gas discharge cylinder 35. A cooling water pipe 25 for cooling the cylinder 4 is provided on the left side of the internal combustion engine 1.

  Four blocking plugs 39 are provided on the upper surface of the breather device 30. This is provided on the ceiling wall 33 of the breather chamber 31 in order to take out the core sand used to secure the space of the breather chamber 31 when the breather chamber 31 is formed integrally with the upper crankcase 2A by casting. The closing plug 39 closes the core extraction through-hole 38. The core sand is taken out from the breathing gas discharge tube mounting hole 36 before the breathing gas discharge tube 35 is mounted, in addition to the core removal through-hole 38 closed by the four closing plugs 39. .

  FIG. 4 is a view of the top surface of the breather device 30 as viewed from above the internal combustion engine 1. Two intake ports 18 corresponding to the two cylinders 4 of the front cylinder block 3F and two intake ports 18 corresponding to the two cylinders 4 of the rear cylinder block 3R are visible. One cylinder is provided with two intake valves 21 and two exhaust valves 22, but only two intake valves 21 are visible at each intake port in the figure. As described above, the drainage groove 23, the drain hole 24, the breathing gas discharge cylinder 35, and the closing plug 39 are provided on the upper surface of the ceiling wall 33. A cooling water pipe 25 is provided on the left side of the internal combustion engine.

  5 is a cross-sectional view taken along the line VV in FIG. In the figure, a lower portion and a bottom surface of the breather chamber 31, cross sections of the cylinder blocks 3F and 3R, and a cross section of the front piston 12 are shown. On the bottom surface of the breather chamber 31, a plurality of maze walls 40 are formed to form a maze in the breather chamber 31.

  A gear train chamber 41 is provided at the right end of the internal combustion engine 1. The gear train chamber 41 is a chamber extending from the crankcase 2 to the cylinder head cover 6, and houses a gear train for driving the camshaft of the valve mechanism 7 by the rotation of the crankshaft 10. In the figure, the drive gear 42 attached to the crankshaft 10 which is the starting point of the gear train is shown. The gear train chamber 41 communicates with the crank chamber 9.

  The crank chamber 9 is filled with blow-by gas leaking from between the cylinder 4 and the piston 12. The main component of blow-by gas is unburned gas. The crank chamber 9 is filled with oil supplied to the rotating portion as oil mist due to the high speed rotation of the gears. Oil mist and blow-by gas are mixed to form oil-mixed blow-by gas. Oil mixed blow-by gas cannot be discharged to the outside air from the viewpoint of environmental protection. For this reason, the oil-mixed blow-by gas is introduced from the crank chamber 9 into the breather chamber 31 through the gear train chamber 41 and the breather chamber inlet hole 43, and is separated into gas and liquid. The separated unburned gas is discharged from the breathing gas discharge cylinder 35 (FIGS. 3 and 6), and recirculated to the internal combustion engine through the air cleaner and burned as described above. The separated oil is discharged from the oil discharge hole 44 (FIGS. 5 and 6) to the AC generator chamber 45 and returned to the oil pan 16 via the AC generator chamber 45 (FIG. 6).

  An inlet barrier 46 is erected on the inside of the breather chamber inlet hole 43 so as to partially overlap the breather chamber inlet hole 43. This prevents the oil from the crankcase 2 from directly flowing in.

  6 is a cross-sectional view taken along the line VI-VI in FIGS. 2 and 4. A part of the front cylinder block 3F is shown in cross section. A partial cross section of the front piston 12, a cross section of the front connecting rod 13, and a large end portion 13 a of the rear connecting rod 13 can be seen through the inner hole of the front cylinder 4. In addition, the labyrinth wall 40 can be seen in the cross section of the breather chamber 31. An alternator chamber 45 is formed on the left side of the crankcase 2 and is generated by an alternator driven by the crankshaft 10. The oil separated in the breather chamber 31 is discharged to the alternator chamber 45 through the oil discharge hole 44 and returned to the oil pan 16 (FIG. 1) through the alternator chamber 45 as a passage. The cross section of the water jacket 26 is visible in the cross section of the front cylinder 4. The water flowing through the cooling water pipe 25 at the left end of the internal combustion engine is supplied to the water jacket 26.

  FIG. 7 is a view of the top surface of the breather device 50 according to the second embodiment of the present invention as viewed from the upper right side of the internal combustion engine. In the second embodiment, a large-sized breathing gas discharge tube mounting base 51 is provided and projects to the periphery and upward. This is formed integrally with the ceiling wall 52 when the breather device 50 is cast. A breathing gas discharge tube mounting hole 54 for attaching the breathing gas discharge tube 53 (FIG. 8) is opened at the center of the breathing gas discharge tube mounting base 51. Further, one core take-out hole 55 is opened on the side. This is closed with an obturator plug 56 (FIG. 8) having the same shape as the obturator plug 39 of the first embodiment after the core is taken out. The other parts are the same as in the first embodiment.

  8 and 9 are sectional views showing the breathing gas discharge tube mounting base 51 and its periphery, FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 7, and FIG. 9 is a sectional view taken along line IX-IX in FIG. It is.

  8 and 9, a breathing gas discharge cylinder 53 is a hexagonal nut used when a breathing gas discharge hose attachment part 57 is attached to the top and the breathing gas discharge cylinder 53 is attached to the breathing gas discharge cylinder attachment hole 54 at the center. A part 58, a male screw part 59 for attachment to the breathing gas discharge cylinder attachment hole 54 under the part 58, and a lower extension part 60 thereunder are provided. The breathing gas discharge cylinder 53 is screwed into the breathing gas discharge cylinder mounting hole 54.

  The breathing gas discharge tube mounting base 51 is provided with a breathing gas discharge tube mounting hole 54 for mounting the breathing gas discharge tube 53 in the upper part, and extends to the periphery below the breathing gas discharge tube mounting hole 54 and above the breather chamber 61. A cavity 62 is provided. The lower surface of the cavity 62 is in full communication with the breather chamber 61. The breather chamber 61 is surrounded by a ceiling wall 52 and a bottom wall 63. The lower extension 60 of the breathing gas discharge tube 53 enters the cavity 62. A cavity 62 exists around the lower extension 60 of the breathing gas discharge cylinder 53. Below the lower opening of the breathing gas discharge cylinder 53, an oil passage holding member 65 having an oil passage 64 for passing lubricating oil therein is provided with a slight gap. The holding member 65 itself functions as the gas outlet barrier 66. Specifically, the oil passage holding member 65 is integrally formed on the ceiling wall 52 so as to cross the breather chamber 61. Further, the oil passage holding member 65 is connected to the ceiling wall 52 by a suspension portion 67 so as to fill a gap with the ceiling wall 52 in the cavity 62. The suspension 67 is formed with a breathing gas discharge cylinder mounting hole 54 communicating in the vertical direction, and further, a gas outflow hole penetrating the breathing gas discharge cylinder mounting hole 54 in a direction transverse to the oil passage 64. 68 is provided in a pair. The lower end of the breathing gas discharge cylinder 53 has a lower extension 60 extending to the gas outflow hole 68, and a labyrinth structure is formed at the lower part of the breathing gas discharge cylinder 53 by the gas outlet barrier 66 to prevent oil from being discharged. ing.

As described in detail above, the following effects are brought about in the first and second embodiments.
(1) When forming the breather device 30 by molding with a mold, the core for forming the breather chamber 31 can be removed from the breathing gas discharge tube mounting hole 36, so that the wall around the breather device 30 is a cylinder. The blocks 3F and 3R can be integrally formed. Thereby, the breather chamber 31 can be reduced in size.
(2) In addition to the breathing gas discharge tube mounting hole 36 in the ceiling wall 33, a core take-out through hole 38 is provided, and a closing plug 39 is fitted into this to form a breather device 30. Removal can be facilitated by increasing the number of extraction holes.
(3) It is possible to prevent oil from flowing directly from the crankcase 2 by standing the inlet barrier 46 in the breather device 30 so as to face the breather chamber inlet hole 43.
(4) By providing the oil discharge hole 44 on the side wall 34 opposite to the breather chamber inlet hole 43, oil can be discharged well without being obstructed by the gas flowing from the breather chamber inlet hole 43. Can do.
(5) Water accumulated on the upper surface of the breather device (30) can be discharged through the drainage groove (23) on the upper surface of the ceiling wall (33).
(6) The drainage groove 23 is formed gradually deeper toward one side in the direction of the crankshaft 10, and the drain hole 24 is provided at the end side wall, so that the water collected on the upper surface of the ceiling wall 33 can be collected and improved. Can be discharged.
(7) In the second embodiment, by forming the gas outlet barrier 66 below the breathing gas discharge tube mounting hole 54, a labyrinth structure in the breather chamber 61 can be formed to improve gas-liquid separation performance. it can.
(8) In the second embodiment, since the labyrinth structure is formed by causing the lower extension portion 60 of the breathing gas discharge cylinder 53 to enter the cavity 62 above the gas outlet barrier 66, the gas-liquid separation performance is improved. Can do.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Crankcase, 2A ... Upper crankcase, 2B ... Lower crankcase, 3F ... Front side cylinder block, 3R ... Rear side cylinder block, 4 ... Cylinder, 10 ... Crankshaft, 12 ... Piston, 23 ... Drainage groove, 24 ... drain hole, 30 ... breather device, 31 ... breather chamber, 32 ... bottom wall, 33 ... ceiling wall, 34 ... side wall, 35 ... breathing gas discharge tube, 36 ... breathing gas discharge tube mounting hole, 38 ... Core removal through-hole, 39 ... plug, 43 ... breather chamber inlet hole, 44 ... oil discharge hole, 46 ... inlet barrier, 50 ... breather device, 53 ... breathing gas discharge tube, 54 ... breathing gas discharge tube installation Hole, 60 ... Lower extension, 61 ... Breather chamber, 62 ... Cavity, 66 ... Gas outlet barrier

Claims (8)

A crankcase (2), and front and rear cylinder blocks (3F, 3R) integrally connected to the crankcase (2) and arranged to form a V-shaped bank,
A plurality of front and rear cylinder blocks (3F, 3R) each provided with a plurality of cylinders (4) paired in front and rear;
Pistons (12) respectively accommodated in the cylinders (4);
An internal combustion engine (1) having a crankshaft (10) supported by the crankcase (2) and rotating in response to sliding of the piston (12),
In the breather device (30) provided in the valley of the V-shaped bank and communicating with the inside of the crankcase (2),
A bottom wall (32) integrally formed by sharing the lower ends of the plurality of cylinders (4) forming the V shape;
A ceiling wall (33) located above the bottom wall (32) and integrally formed across the plurality of V-shaped cylinder blocks (3F, 3R);
Side walls (34) forming a breather chamber (31) of the breather device (30) by closing both ends in the direction of the crankshaft (10) between the V-shaped cylinder blocks (3F, 3R). )When,
A breather chamber inlet hole (43) provided on at least one of the side walls (34) and communicating with the crankcase;
In addition, the breathing gas discharge cylinder (35) for connecting a hose for discharging gas from the breather chamber (31) is attached to the breathing gas discharge cylinder mounting hole (36) provided in the ceiling wall (33). Breather device (30) featuring. Apart from the breathing gas discharge tube mounting hole (36), it has a through hole (38) for taking out the core formed in the ceiling wall (33),
2. The breather device (30) according to claim 1, wherein a closing plug (39) is fitted into each of the core take-out through holes (38) to close the breather device (30).   The inlet barrier (46) is erected inside the breather device (30) so as to overlap a part of the breather chamber inlet hole (43). Breather device (30).   Of the side wall (34), an oil discharge hole (44) for discharging oil accumulated in the breather device (30) is provided on the side wall (34) opposite to the side where the breather chamber inlet hole (43) is provided. The breather device (30) according to any one of claims 1 to 3, wherein the breather device (30) is provided.   The drainage groove (23) is formed on the top surface of the ceiling wall (33) so as to be recessed inward of the breather device (30) and extending in the direction of the crankshaft (10). Breather device (30) given in any 1 paragraph.   The drainage groove (23) on the upper surface of the ceiling wall (33) is formed to be gradually deeper toward one side in the direction of the crankshaft (10), and a drain hole (24) is provided on the end side wall. The breather device (30) according to claim 5.   The gas outlet barrier (66) is formed below the breathing gas discharge tube mounting hole (54) to which the breathing gas discharge tube (53) is mounted. The breather device (50) according to item 1.   A cavity (62) extending around the breather chamber (61) is formed below the breathing gas discharge tube mounting hole (54) and above the gas outlet barrier (66). The breather device (50) according to claim 7, wherein the breathing gas discharge tube (53) is attached so that the lower extension (60) of the breathing gas discharge tube (53) enters.

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