JP3384220B2 - Breather system for outboard engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breather device for an outboard motor engine. 2. Description of the Related Art FIG. 4 is a longitudinal sectional view of a general engine used for an outboard motor. In the engine 1 for an outboard motor, since the crankshaft 3 is directly connected to the drive shaft 2 arranged substantially vertically, the crankshaft 3 is generally arranged almost vertically like the drive shaft 2. [0003] The crankshaft 3 is arranged in an engine case 5 which is divided into front and rear parts around an axis 4 of the crankshaft 3. Further, of the engine case 5 divided into front and rear, the rear side, the right side in FIG. 4, is a cylinder block 7 in which a cylinder 6 is formed.
In FIG. 4, the bearing cap 8 is on the left side. FIG. 5 is a sectional view taken along the line VV of FIG. As shown in FIGS. 4 and 5, the crankshaft 3
Is a bearing boss 1 provided inside a divided portion of the cylinder block 7 and the bearing cap 8 via the bearing 9.
0 and 11 are held. An oil drop passage 12 is formed in the bearing bosses 10 and 11 so that the lubricating oil can drop downward from above. Further, a stator base 13 is disposed on the upper surface of the engine case 5. This stator base 1
Reference numeral 3 is fixed across both the cylinder block 7 and the bearing cap 8. An upper end of the crankshaft 3 protrudes from the upper surface of the cylinder block 7, and a magnet 14 and a recoil starter 15 are attached to the upper end. By the way, in the engine 1, a small amount of gas with pressure generated in the combustion chamber leaks into the engine case 5 through a gap between the piston 16 and the cylinder 6. Further, since the pressure of the gas in the engine case 5 constantly fluctuates as the piston 16 slides, if the engine case 5 is in a sealed state, the gas in the engine case 5,
The pressure of the so-called blow-by gas impedes the movement of the piston 16. Therefore, it is necessary to provide a means for releasing the blow-by gas in the engine case 5 to the outside, that is, a breather device. Therefore, the crank chamber 17 in which the crankshaft 3 is disposed in the engine case 5 communicates with the space formed in the cylinder head 18 and the head cover 19, that is, the cam chamber 20 through the communication passage 21. Further, the blow-by gas outlet 2
2 is provided to discharge blow-by gas in the engine case 5 to the atmosphere. [0008] However, in order to secure a large volume of the crank chamber, that is, a large volume of the breather in order to enhance the breather effect, the size of the oil drop passage must be increased. The bearing cap becomes large and the weight of the engine increases. In addition, the size of the oil drop passage is easily affected by the shape of the bearing boss, which also affects the shape of the communication passage that connects the crank chamber and the cam chamber. On the other hand, when inspecting and maintaining the inside of the engine case, the bearing cap cannot be removed unless the stator base and the like disposed on the upper surface of the engine case are once removed, resulting in poor maintainability. The present invention has been made in view of the above-mentioned circumstances, and provides a breather device for an outboard motor engine capable of securing a sufficient oil drop passage and a breather volume without increasing the size of the engine. The purpose is to do. [0012] breather device of an engine for an outboard motor according to the present invention SUMMARY OF THE INVENTION To solve the problems described above, as described in claim 1, the engine Shirindabu
While forming multiple cylinders in the lock in the vertical direction,
The cylinder block has an opening that opens to one side,
Place the crankshaft almost vertically inside this opening.
On the other hand, open the cylinder block
Cover with the back cover and the other side of the cylinder block.
Cylinder head with cam chamber communicating with atmosphere
And the cylinder located at the top of the cylinder block
The above-mentioned cam chamber and the above-mentioned oil are
Breather for outboard engine that communicates with the drop-off passage
In the apparatus, the crankshaft is connected to the cylinder shaft.
A bearing boss formed inside the opening of the lock and this bearing
Holding by bearing cap fixed to boss
With the front edge of the cylinder block opening
The cylinder block cover side from the axis of the link shaft
Set to above and above bearing boss and bearing cap and
The space formed between the cylinder block cover and the inner surface
An oil drop passage is formed at the bottom . Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a left side view of an outboard motor to which the present invention is applied. As shown in FIG. 1, the outboard motor 30 includes an engine holder 31, and an engine 32 is installed on the engine holder 31. The engine holder 31
The engine 32 installed above is covered by an engine cover 33. The engine 32 is, for example, a four-cycle multi-cylinder engine, and is configured by combining a cylinder block 34, a cylinder block cover 35, a cylinder head 36, a cylinder head cover 37, and the like. FIG. 2 is a longitudinal sectional view of the engine 32, and FIG. 3 is a sectional view taken along line III-III of FIG. As shown in FIGS. 1 to 3, the cylinder block 34 has an opening 38 that opens to the left in FIG. 2, for example, on the traveling direction side of a ship (not shown) to which the outboard motor 30 is attached. Inside the opening 38, a crankshaft 39 is disposed substantially vertically. The opening 38 of the cylinder block 34 is covered by a cylinder block cover 35. And the cylinder block 34 opening part 3
The front edge 38 a of the cylinder 8 is set on the traveling direction side of the axis 40 of the crankshaft 39, that is, on the cylinder block cover 35 side. The crankshaft 39 includes a bearing boss 41 whose journal portion 39a is formed inside the open portion 38 of the cylinder block 34, and a bolt 4
The bearing cap 43 fixed at 2 holds the bearing via a bearing 44. Then, an oil drop passage 45 is formed in a space formed between the bearing boss 41 and the bearing cap 43 and the inner surface of the cylinder block cover 35.
Is formed. On the other hand, a plurality of cylinders 46a to 46d are formed in the cylinder block 34 in the vertical direction. A piston 47 is slidably inserted in each of the cylinders 46a to 46d in a horizontal direction.
9 are connected by a connecting rod 48. Then, the reciprocating stroke of the piston 47 is converted into the rotational movement of the crankshaft 39. Further, an upper end of the drive shaft 49 is connected to a lower end of the crankshaft 39. An oil seal housing 50 is provided on the upper surface of the cylinder block 34. In addition, the stator base 51 is similarly arranged on the upper surface of the cylinder block 34. Further, the upper end of the crankshaft 39 protrudes from the upper surface of the cylinder block 34, and the magnet 5
2 and the recoil starter 53 are attached. A cylinder head 36 is arranged on the side of the cylinder block 34 opposite to the opening 38, and a cam mechanism 54 in the cylinder head 36 is provided with a valve mechanism (not shown). The cam chamber 54 is covered by the cylinder head cover 37. The cam chamber 54 and the oil drop passage 45
Are communicated by the communication passage 55. This communication path 55
Is disposed near the cylinder 46a located at the uppermost part of the engine 32. The cylinder head cover 37 is provided with a blow-by gas discharge port 56. The blower gas outlet 56 and the communication path 55 constitute a breather device 57. The breather device 57 is generated in a combustion chamber, and includes a piston 47 and cylinders 46a to 46d.
The blow-by gas leaked into the crank chamber 58 in which the crankshaft 39 is disposed through a gap between the blow-by gas and the blow-by gas is discharged to the atmosphere. On the other hand, a drive shaft housing 59 is provided below the engine holder 31. A shaft pipe 60 is formed in a drive shaft housing 59, and the drive shaft 49 extends downward in the shaft pipe 60, and a bevel gear and a propeller shaft (not shown) in a gear case 61 provided at a lower portion of the drive shaft housing 59. Is configured to drive the propeller 62 via the. Next, the operation of the present embodiment will be described. The leading edge 3 of the opening 38 of the cylinder block 34
8a is set closer to the cylinder block cover 35 than the axis 40 of the crankshaft 39, the crankshaft 39 is arranged inside the opening 38, the crankshaft 39 is held by the bearing cap 43, and the cylinder block 34 By covering the opening 38 with the cylinder block cover 35, a sufficiently large oil drop passage 45 can be secured without increasing the size of the engine 32. In addition, the volume of the crank chamber 58, that is, the breather volume can be ensured to be equal to or larger than the conventional one, and the breather effect can be enhanced. Further, since the bearing cap 43 is not provided integrally with the cylinder block cover 35 as in the prior art, the cylinder block cover 35 does not require much strength, and the material of the cylinder block cover 35 is a non-metallic material such as resin. And the weight of the engine 32 can be reduced. Further, by setting the front edge 38a of the open portion 38 of the cylinder block 34 on the side of the advancing direction from the axis 40 of the crankshaft 39, the cylinder block 3 does not straddle the upper surface of the cylinder block cover 35.
Peripheral devices such as the oil seal housing 50 and the stator base 51 can be installed only on the upper surface of the device 4. As a result, when inspecting and maintaining the inside of the cylinder block 34, the cylinder block cover 35 can be removed without removing the stator base 51 and the like arranged on the upper surface of the cylinder block 34, and the maintainability is improved. The cam chamber 54 and the oil drop passage 45
Is arranged near the cylinder 46a located at the uppermost part of the engine 32, the blow-by gas containing less oil can be discharged into the atmosphere. As described above, according to the breather device for an outboard motor engine according to the present invention, the engine serial
When multiple cylinders are formed vertically in a cylinder block,
In both cases, the cylinder block has an open part that opens to one side.
With the crankshaft almost vertically inside this opening
While placing the cylinder block, open the cylinder block
Cover with the cylinder block cover and the cylinder block
Cylinder head with a cam chamber communicating with the atmosphere on the other side
To the top of the cylinder block.
The cam chamber and upper part are connected by a communication passage located near the cylinder.
The outboard motor engine block communicating with the oil drop passage
In the riser device, the crankshaft is connected to the series.
Bearing boss formed inside the open part of the
With a bearing cap fixed to the bearing boss
While holding up the front edge of the cylinder block opening.
From the axis of the crankshaft,
Set to the bar side, and use the bearing boss and bearing
Formed between the cylinder and the cylinder block cover inner surface.
The oil drop passage was formed in the
Ensuring a large enough oil drop passage without molding
As a result, the breather volume can be sufficiently secured,
Blow bar with low oil content as well as improved
Igus can be discharged into the atmosphere. [0029]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a left side view of an outboard motor showing one embodiment of a breather device for an outboard engine according to the present invention. FIG. 2 is a longitudinal sectional view of the engine. FIG. 3 is a cross-sectional view of the engine shown in FIG. 2, taken along the line III-III. FIG. 4 is a longitudinal sectional view of an engine used in a conventional outboard motor. FIG. 5 is a cross-sectional view of the engine shown in FIG. 4, taken along line VV. [Description of Signs] 30 Outboard motor 32 Engine 34 Cylinder block 35 Cylinder block cover 36 Cylinder head 38 Cylinder block opening 38a Front edge 39 of cylinder block opening 39 Crankshaft 40 Crankshaft axis 41 Bearing boss 43 Bearing cap 45 Oil drop passages 46a to 46d Cylinder 54 Cam chamber 55 Communication passage 57 Breather device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-178817 (JP, A) JP-A-7-77024 (JP, A) JP-A-2-124209 (JP, U) (58) Survey Field (Int. Cl. ⁷ , DB name) F01M 13/00 F02B 67/00

Claims (1)

(57) [Claims 1] A plurality of cylinders in an engine cylinder block
While forming the cylinder in the vertical direction,
The pocket has an opening that opens to one side, and the inside of this opening
While the crankshaft is placed almost vertically
Cover the open part of the cylinder block with the cylinder block cover
At the same time, the other side of the cylinder block communicates with the atmosphere
A cylinder head having a cam chamber is arranged, and the cylinder
Located near the cylinder located at the top of the block
A communication passage connects the cam chamber with the oil drop passage.
In the breather device for the outboard engine
Place the crankshaft in the open part of the cylinder block.
Bearing boss formed on the side and fixed to this bearing boss
While holding with the bearing cap,
Align the front edge of the open block with the crankshaft shaft
Set the cylinder block cover side from the
Bearing boss and bearing cap and the above cylinder block
Oil drop passage in the space formed between
Breather system for an outboard motor engine, characterized in that the formation of the.