JP3943306B2 - Engine breather equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, a breather chamber is provided inside the mating portion of each of the half crankcase halves, and blow-by gas is guided from the breather chamber to a reduction chamber of an air cleaner disposed outside the engine via a blow-by gas pipe. The present invention relates to a breather device configured, and particularly relates to a blower gas pipe that is made as short as possible.
[0002]
[Prior art]
In Japanese Patent Laid-Open No. 11-36841, in a vehicle equipped with a vertical engine in which the axial direction of the crankshaft is arranged parallel to the longitudinal direction of the vehicle body, a blow-by gas pipe is connected from the crankcase to an air cleaner disposed behind the engine. A breather device is shown. Japanese Patent No. 2646496 discloses that a breather chamber is provided inside the mating portion of the crankcase divided into left and right parts.
[0003]
[Problems to be solved by the invention]
By the way, the longitudinal engine is a breather device in which a breather chamber is formed inside the mating portion of the front and rear crankcase halves and blowby gas is reduced to a reduction chamber of an air cleaner disposed behind the engine. In this case, the routing of the blow-by gas pipe is determined by the blow-by gas outlet, and the position of the blow-by gas outlet is aligned with the crank case cover that covers the rear crank case half from the front and rear crank case half-matching portions. It is limited to the range to the part.
[0004]
In addition, in the case of a vertically mounted engine, the air cleaner is inherently long in the front-rear direction, and the air cleaner is disposed further rearward of the crankcase cover located at the rear end portion, so that the blow-by gas piping must be relatively long. However, if the piping becomes longer in this way, the cost increases accordingly and the weight increases. In addition, if a special pipe line is formed to increase the number of parts, the risk of failure may increase accordingly. Therefore, the blow-by gas piping is required to be as short as possible, and the present application aims to meet such a request.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problem, the breather device for an engine according to the present invention is provided with a breather chamber inside the mating portion of each of the two divided crankcase halves, and from the breather chamber to a reduction chamber of an air cleaner disposed outside the engine. In the breather device configured to guide the blow-by gas through the blow-by gas piping,
In one of the crankcase halves, a case-side passage is integrally provided with one end opened to the breather chamber and the other end opened to the mating portion with the crankcase cover.
A cover-side passage that penetrates the crankcase cover is provided, and one end of the cover-side passage is opened at a mating portion with the crankcase half and connected to the other end of the case-side passage, so that a breather passage in the engine And the other end of the cover-side passage projects outward from the crankcase cover to form an outlet joint portion, to which one end of the blow-by gas pipe is connected.
[0006]
At this time, the case side passage can be formed through the thick portion of the crankcase half and the cover side passage can be formed through the thick portion of the crankcase cover. Further, the engine is a vertically mounted engine, the case side passage is provided in the rear crankcase half, the cover side passage is provided in the rear cover that covers the rear side of the rear crankcase, and the rear cover is provided behind the rear cover. An air cleaner can also be placed.
[0007]
【The invention's effect】
A breather chamber is formed inside the mating part of each crankcase half, and a case side passage is provided inside one of the crankcase halves, and a cover side passage is provided in a crankcase cover covering the crankcase half, and both passages are provided. Since these two passages form a continuous breather passage in the engine, the blow-by gas in the breather chamber passes through the breather passage and is connected to the blow-by gas pipe at the outlet joint portion outside the crankcase cover. Then, it passes through here and is returned to the reduction chamber of the air cleaner arranged outside the engine.
[0008]
Therefore, since the breather passage inside the engine subsidizes part of the blow-by gas piping, out of the conventionally required blow-by gas piping, there is no need for external piping that passes through at least the outside of the crankcase cover. Can be made as short as possible. As a result, the stays and clamps for external piping can be reduced, so that cost and weight can be reduced. In addition, since the breather passage inside the engine is formed integrally with the crankcase half and the crankcase cover, an increase in the number of parts can be prevented, and an increase in failure risk due to the increase in the number of parts can be prevented.
[0009]
If the case side passage is formed through the thick part of the crankcase half and the cover side passage is formed through the thick part of the crankcase cover, the crankcase half and the crankcase cover are formed. Since it is not necessary to occupy the internal space, the effective internal volume can be increased and the passage can be easily formed. In addition, when applied to a vertically mounted engine, this engine is essentially long in the front-rear direction, and the rear crankcase half is disposed despite the fact that an air cleaner is disposed further rearward of the rear crankcase cover provided at the rear part. Since the breather passage provided in the rear crankcase cover can be substituted for a part of the blow-by gas pipe, the blow-by gas pipe can be shortened as much as possible, and a breather device suitable for a longitudinal engine is obtained.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the main part of the engine showing the blow-by gas passage (cross-section corresponding to line 1-1 in FIG. 3), FIG. 2 is a partially cutaway side view of the entire engine, and FIG. FIG. 4 is a view showing the mating portion in the breather chamber portion of the front crankcase from the rear, FIG. 5 is a view showing the case-side passage portion in the rear of the rear crankcase from the rear, and FIG. The figure which shows a side channel | path part from the front of an engine, FIG. 7 is a figure which shows the back side.
[0011]
First, in FIG. 2, this engine is an OHV (overhead valve) type vertical four-cycle engine, in which the central axis of the crankshaft 1 is arranged in parallel to the front-rear direction of the vehicle body. It is a front and rear wheel drive type that transmits driving force to the output shaft 3 and further drives the front propeller shaft 4 and the rear propeller shaft 5 from here.
[0012]
The case portion of this engine includes a front crankcase 6 and a rear crankcase 7 which are crankcase halves divided into front and rear. The front crankcase 6 is covered with a front cover 8 at the front, and the rear crankcase 7 The rear side is covered with a rear cover 9. The rear crankcase 7 is a rear crankcase half in the present invention, and the rear cover 9 is also a rear crankcase cover that covers the rear crankcase half. These front and rear crankcase halves and the crankcase cover are made of an appropriate metal material such as an aluminum alloy by an appropriate manufacturing method such as casting, and these constitute a case of a vertically placed engine that is long in the front-rear direction.
[0013]
As shown in FIGS. 1 and 3, a cover-side passage 10 is provided in the rear right shoulder of the rear cover 9 when the engine is mounted on the vehicle body. The cover-side passage 10 is made of a metal pipe that is separate from the rear cover 9, and one end side is press-fitted into a pipe hole 12 formed through the thick portion 11 in the shoulder portion of the rear cover 9 in the front-rear direction. The press-fit end 13 faces the mating surface of the rear crankcase 7 and the other side projects rearward from the rear cover 9 to form an outlet joint portion 14 to which one end of a blow-by gas pipe 15 such as a rubber tube is connected. ing.
[0014]
The other end of the blow-by gas pipe 15 extends rearward of the vehicle body, and is connected to a reduction chamber of an air cleaner that is not shown here but is arranged behind the engine. The press-fit end 13 of the cover-side passage 10 is connected to a pipe-like case-side passage 17 formed in a pipe-like shape penetrating through the thick portion 16 provided in the right shoulder of the rear crankcase 7 in the front-rear direction. These two passages constitute a continuous breather passage 18 that is integrated into the engine.
[0015]
The front end of the case side passage 17 is connected to a breather chamber 20 formed on both sides of the front crankcase 6 and the rear crankcase 7 inside the mating portion with the front crankcase 6. The breather chamber 20 communicates with the crank chamber 19 and collects blow-by gas flowing into the interior of the breather chamber 20. In addition, the breather chamber 20 in FIG. 1 shows a schematic shape.
[0016]
Reference numeral 21 in FIG. 1 is a cam shaft, 22 is a cam sprocket, 23 is a cam, 24 is a cam follower, 25 is a push rod that drives an overhead valve of an OHV engine, and 26 is a push that accommodates the push rod in a vertically movable manner. The rod hole 27 is a cylinder block, and the breather chamber 20 is in a position overlapping the push rod hole 26 in FIG. Reference numeral 30 in FIG. 3 is a bolt for attaching the rear cover 9 to the rear crankcase 7, and 31 is a bolt for attaching the rear crankcase 7 to the front crankcase 6.
[0017]
As shown in FIG. 4, a concave portion 28 is formed on the front half side of the breather chamber 20 formed on the front crankcase 6 side, and this concave portion 28 is formed at a position overlapping the right side of the camshaft 18. It faces the mating surface 6a with the case 7 and is opened rearward. On the other hand, a similar concave portion constituting the rear half of the breather chamber 20 is also formed on the rear crankcase 7 side, and when the rear crankcase 7 is combined, one breather chamber 20 is formed.
[0018]
Ribs 29 are formed integrally in the recesses 28 so as to protrude alternately in a horizontal direction toward the facing wall, thereby forming a maze structure in the breather chamber 20 to promote gas-liquid separation. It is like that. Reference numeral 31a denotes an attachment portion for attaching the rear crankcase 7 with the bolt 31, and a screw hole is formed therein.
[0019]
FIG. 5 shows the case-side passage 17 portion on the rear surface of the rear crankcase 7 from the rear, and it cannot be seen from the rear side in this figure, but corresponds to the recess 28 on the mating surface side with the front crankcase 6 as described above. A similar concave portion is formed at the position to constitute the rear half of the breather chamber 20. The case side passage 17 is formed so as to penetrate the thick portion 16 in the right shoulder of the rear crankcase 7 in the front-rear direction, and the rear end side is open to the mating surface 9 a of the rear cover 9.
[0020]
Reference numeral 30b in the drawing is an attachment portion for fastening the rear crankcase 9 with the bolt 30 and is formed as a screw hole. Reference numeral 31b denotes an attachment portion for attaching the front crankcase 6 to the front crankcase 6 with a bolt 31, which is formed as a through hole.
[0021]
As is apparent from FIG. 6, the press-fit end 13 of the cover-side passage 10 that penetrates the thick portion 11 formed on the right shoulder of the rear cover 9 opens to the mating surface 9 a for the rear crankcase 7 of the rear cover 9. When the mating surface 9a of the rear cover 9 is aligned with the mating surface 7a of the rear crankcase 7, the thick portion 11 overlaps with the thick portion 16 of the rear crankcase 7, and the outlet of the case side passage 17 The press-fit end 13 which is the entrance of the cover side passage 10 is made to coincide.
[0022]
Therefore, when the attachment portion 30c configured as a through hole is made to coincide with the attachment portion 30b of the rear crankcase 7 and fastened with the bolt 30, the case side passage 17 and the cover side passage 10 are connected to each other and connected one by one. A breather passage 18 is formed in the engine, and the blow-by gas in the breather chamber 20 is guided to the blow-by gas pipe 15.
[0023]
Next, the operation of this embodiment will be described. When the mating surface 6a of the front crankcase 6 and the corresponding mating surface of the rear crankcase 7 are matched, the mounting portions 31a and 31b are aligned and fastened with bolts 31, the crankcase is assembled and at the same time the breather chamber 20 It is formed inside the mating part of the case 6 and the rear crankcase 7.
[0024]
Subsequently, when the rear crankcase 7 rear side mating surface 7a and the rear cover 9 mating surface 9a are overlapped and the mounting portions 30b and 30c are aligned with each other and fastened with bolts 30, the rear cover 9 is attached to the rear surface of the rear crankcase 7. Simultaneously with the mounting, the case side passage 17 and the cover side passage 10 are connected in communication, and the breather passage 18 is integrally formed in the engine in the front-rear direction.
[0025]
Therefore, if one end of the blow-by gas pipe 15 is connected to the outlet joint portion 14 of the cover-side passage 10 protruding to the back surface of the rear cover 9, the breather chamber 20 is connected to the air cleaner via the breather passage 18 and the blow-by gas pipe 15. Connected to the reduction chamber, blow-by gas in the breather chamber 20 is guided to the reduction chamber of the air cleaner.
[0026]
In this way, the case side passage 17 is integrally formed inside the rear crankcase 7, and the cover side passage 10 is formed inside the rear cover 9, and this is formed at each joint portion of the rear crankcase 7 and the rear cover 9. Since the breather passage 18 which is a conduit for guiding the blow-by gas into the engine is formed by the communication connection, the breather passage 18 can be used as a part of the blow-by gas pipe, and the blow-by gas pipe 15 outside the engine can be submerged. Since only the air cleaner is connected from the projecting end portion 14 projecting from the back surface of the rear cover 9, it can be shortened by at least the length of the rear cover 9 in the front-rear direction.
[0027]
As a result, the blow-by gas pipe 15 can be shortened as much as possible, and the stays and clamps for fixing the blow-by gas pipe 15 can be reduced, so that the cost and weight can be reduced accordingly. In addition, since the breather passage 18 inside the engine is formed integrally with the rear crankcase 7 and the rear cover 9, there is no need to form a pipe line using special parts, and an increase in the number of parts can be prevented. As the number decreases, the risk of failure decreases accordingly.
[0028]
In addition, the case side passage 17 is formed through the thick portion 16 of the rear crankcase 7 and the cover side passage 10 is formed through the thick portion 11 of the rear cover 9, so that the breather passage 18 is formed. Since it is not necessary to occupy the space inside the rear crankcase 7 and the rear cover 9, these effective internal volumes can be increased, and the formation of the breather passage 18 can be facilitated.
[0029]
In addition, since the engine is applied to a vertical engine, the engine is essentially long in the front-rear direction, and an air cleaner is disposed further rearward of the rear cover 9 provided at the rear portion thereof, but the rear crankcase 7 and the rear cover 9 are disposed inside. Since the provided breather passage 18 can be substituted for a part of the blow-by gas piping, the blow-by gas piping 15 outside the engine can be shortened as much as possible, and a breather device suitable for a longitudinal engine is obtained.
[0030]
The present invention is not limited to the above-described embodiments, and various modifications and applications are possible. For example, the engine may be not only a vertical type but also a horizontal type with a crankshaft directed in the left-right direction. Further, the breather passage 18 does not necessarily have to be formed through the thick portion, but an integral passage may be formed at an arbitrary position inside the crankcase and the crankcase cover in casting or the like. Further, the cover side passage 10 presses a separate pipe into the through hole 12, but this may be omitted and the rear cover 9 itself including the outlet joint portion 14 may be formed integrally.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of an engine showing a blow-by gas passage according to an embodiment. FIG. 2 is a partially cutaway side view of the whole engine. FIG. 3 is a view showing an outlet joint part from the rear of the engine. 4 is a view showing the mating portion of the front crankcase from the rear. FIG. 5 is a view showing the blow-by gas passage portion on the back of the rear crankcase from the rear. FIG. 6 is a view showing the cover-side passage portion on the front of the rear cover from the front of the engine. FIG. 7 is a diagram showing the back side.
1: crankshaft, 6: front crankcase, 7: rear crankcase, 8: front cover, 9: rear cover, 10: cover side passage, 14: outlet joint, 15: blow-by gas piping, 17: case side passage , 18: Breather passage, 20: Breather room

Claims (3)

A breather device is provided in which a breather chamber is provided inside the mating portion of each of the two divided crankcase halves, and blowby gas is guided from the breather chamber to a reduction chamber of an air cleaner disposed outside the engine through a blowby gas pipe. In
A cover that penetrates the crankcase cover and is integrally provided with a case-side passage having one end opened to the breather chamber and the other end opened to the mating portion with the crankcase cover inside one of the crankcase halves. A side passage is provided, one end of the cover side passage is opened at a mating portion with the crankcase half and connected to the other end of the case side passage to form a breather passage in the engine, and the cover side passage The other end of the engine is projected outward from the crankcase cover to form an outlet joint portion, to which one end of the blow-by gas pipe is connected. 2. The engine according to claim 1, wherein the case-side passage is formed through the thick part of the crankcase half and the cover-side passage is formed through the thick part of the crankcase cover. Breather device. The engine is a vertical engine, the case side passage is provided in a rear crankcase half, the cover side passage is provided in a rear cover that covers the rear side of the rear crankcase, and the air cleaner is disposed behind the rear cover. The engine breather device according to claim 1, wherein:

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