JP3038680B2 - Breathing structure of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breathing structure for venting a crankcase in an internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine in which an oil return path and a breather path are formed on the side of a cylinder, a conventional example in which a crank weight rotates in a direction to descend on the breather path side (Japanese Utility Model Laid-Open No. 62-175206) is described. This is illustrated in FIG.

A cylinder head 02 is connected above the cylinder block 01, and a rocker cover 03 covers a valve mechanism 09 above the cylinder head 02, while an oil pan 04 is mounted below the cylinder block 01. , The lower part of the cylinder block 01 and the oil pan 04 constitute a crankcase 05.

A connecting rod 08 connects a piston 07 which moves up and down in the cylinder and a crankshaft 06 which rotates in the direction of the arrow in the crankcase 05. The oil return path 010 formed on the side of the cylinder, the breather path 011 and the upper part of the cylinder head 02 communicate with the inside of the crankcase 05.

[0005] The oil stored in the oil pan 04 is supplied to the valve operating mechanism 09 by an oil pump, and is supplied to the valve operating mechanism 09.
9 is supplied to the upper surface 2a of the cylinder head 02.
After flowing into the crankcase 05 through the oil return path 010, the oil returns to the oil pan 04.

On the other hand, the blow-by gas leaked into the crankcase 05 passes through the breather path 011 and the rocker cover 0.
3 and flows into the intake manifold via a breather hose (not shown). The breather passage 011 is provided with an oil pan 04 through an oil return passage 010.
It also acts as an air vent hole to make it easier to return to.

[0007]

The crank weight rotating integrally with the crankshaft 06 is rotating in the descending direction on the breather path 011 side. When the crank weight scrapes oil splashing in the crank case, the crank weight rotates to a certain high speed. A film (oil curtain) is formed above the crankcase 05 by the stirred oil.

[0008] This oil curtain is used for breather road 011.
The opening of the lower end is blocked to prevent communication, and the conduction of the breather passage 011 is deteriorated, so that smooth return of oil is prevented.

[0009] The present invention has been made in view of such a point,
The purpose thereof is to provide a breathing structure which always secures a breather passage and realizes smooth oil circulation.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention according to claim 1 is directed to a cylinder relative to the cylinder.
In an internal combustion engine in which an oil return path and a breather path are respectively formed on the sides to be rotated, and a crank weight rotates in a direction to descend on the breather path side, the internal combustion engine extends downward from the lower end opening of the breather path along the inner surface of the crankcase. A breather plate is provided, a passage leading to the breather passage is formed between the breather plate and the inner surface of the crankcase, and a connecting rod is provided at an upper end of the breather plate.
Notch opening to the breather path to avoid interference with
Is formed in the breathing structure of the internal combustion engine.

A breather plate extending downward from the lower end opening of the breather passage along the inner surface of the crankcase forms a passage leading to the breather passage between the breather plate and the inner surface of the crankcase. The resulting oil curtain is shut off by the breather plate, and the breather passage is always secured, so that the oil can be returned smoothly.

In addition, the crank weight is on the breather road side.
As it descends, the oil pool
Oil scraping and splashing when the weight rises
Inside the passage from the lower opening of the passage formed by the breather plate
Oil components along with blow-by gas
Backflow to the cleaner increases oil consumption or evaporates
They do not stain the vessels with oil.

The cutout at the upper end of the breather plate is
Since it is formed to avoid interference with the
It is displaced from the weight in the rotation axis direction and the crankway
Position outside the rotation of the
And also acts as a breather passage, reducing the passage area.
Can be increased. Also the cutout of the breather plate
Since the part is a escape for the connecting rod,
Can be configured to impact.

According to a second aspect of the present invention, the cylinders
Oil return path and breather path are formed on each side
And the crank weight descends on the breather road side
In the internal combustion engine rotating in the opposite direction, the lower end of the breather path
Extended downward from the opening along the inner surface of the crankcase
Install a breather plate,
A passage leading to the breather path between the inner case
The breather plate is formed with the upper end below the cylinder
Fixed to the end, the lower end is the lower end of the outer wall of the cylinder block
The breathing structure of an internal combustion engine
You.

The oil curtain is formed by the breather plate.
It is shut off and the breather passage is always secured, and the oil returns
Can be smoothed and the crank weight rises
When oil is scraped and splashed, it forms a breather plate
It does not enter the passage from the lower opening of the passage. Since the breather plate connects the lower end of the cylinder and the vicinity of the lower end of the outer wall of the cylinder block, the strength of the cylinder block can be improved. Further, since the breather plate is sufficiently extended downward, it is possible to reliably prevent the breather passage from being blocked by the oil curtain.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention shown in FIGS. 2 to 11 will be described below. The present embodiment is applied to a four-cylinder engine.
2 and 3 show top and bottom views of FIG.
FIG. 4 is a sectional view including a V-IV section and other members.
The enlarged bottom view is shown in FIG.

The cylinder block 10 has a substantially rectangular shape which is long from front to back as viewed from above, and includes four cylinders 11,
12, 13, and 14 are arranged side by side in one row before and after. The cylinder block 10 includes the cylinders 11, 12, 13, 1
4 comprises an upper half 10a provided side by side and a lower half 10b forming a part of the crankcase 15 (see FIG. 3).
A space is formed below each of the cylinders 11, 12, 13, and 14 by a bearing wall 10c of the crankshaft, and a space is formed. An oil pan 40 is attached from below to form a crankcase 15. .

The upper half 10 of the cylinder block 10
1A, one side of the front and rear cylinders 11 and 14 has breather passages 16 and 1 forming blow-by gas passages, respectively.
7 is provided along the cylinders 11 and 14, and the breather passages 16 and 17 are provided in a space for accommodating a valve operating mechanism through a breather passage of a cylinder head which is joined above the cylinder block 10 and the inside of a lower crankcase 15. To communicate. On the other side of the cylinders 11 and 14, oil return paths 18 and 19 are formed along the cylinders 11 and 14, and communicate the oil bath on the upper surface of the cylinder head with the inside of the crankcase 15.

The breather passages 16 and 17 and the oil return passage 19 each have two passages each having an upper half formed in parallel with two rectangular cross sections, and are joined together in a lower half. The cross section is formed by a single flat rectangular passage. As shown in FIG. 4, the lower end openings 16a and 18a of the breather passage 16 and the oil return passage 18 are formed on both sides of the lower end 11a of the cylinder 11 so as to gradually increase in opening area as going downward.

The balancer shafts 35, 36 are rotatably mounted in the widened openings 16a, 18a in the front-rear horizontal direction. The balance weights provided integrally with the balancer shafts 35 and 36 are connected to the inner cylinder 1
Because it is located on the side of 2, 13 the breather path 16, 1
7. The oil return paths 18 and 19 are formed on the sides of the front and rear cylinders 11 and 14 avoiding the balance weight.

The breather plates 25 and 26 are mounted below the breather passages 16 and 17 provided on the sides of the front and rear cylinders 11 and 14, respectively. 25 will be described below with reference to FIGS.

A pair of bolt holes 20, 20 are formed in the lower surface of the lower end 11a of the cylinder 11 on the side of the breather passage 16 at the front and rear. Are a pair of front and rear bolt holes 21 and 2 near the outer wall 10d corresponding to the bolt holes 20 and 20, respectively.
1 is also drilled upward. The breather plate 25 is screwed into at least four bolt holes of the cylinder block 10, including the bolt holes 20, 20 at the lower end 11a of the cylinder 11 and the bolt holes 21, 21 of the bearing wall 10c. The bolt holes 20, 20 are located on the upper side inside the crankcase 15, and the bolt holes 21, 21 are located below and outside the bolt holes 20, 20, slightly inside the lower end of the outer wall 10d, and the front and rear bolt holes 21, 21 are located. Are slightly larger.

FIGS. 6 to 8 show the shape of the breather plate 25 attached to the bolt holes 20, 20, 21, 21. FIG. The breather plate 25 has a shape obtained by bending a generally vertically long rectangular flat plate, and has a curved portion 25a.
Is formed with a lattice-shaped recessed portion 25b for reinforcement, the upper end of which is bifurcated with a notch 25c at the center, and the tip 25d is bent in the horizontal direction. Bending part 2
The shoulder 25e from 5a to the tip 25d is slightly recessed inward. On the other hand, the lower end portion is bent inward, and both sides of the bent portion are extended outward to form a flange 25f. Horizontal top end 2 of the breather plate 25
5d and a small hole 25g in the lower end flange 25f, respectively.
25 h are provided and correspond to the bolt holes 20 and 21 on the cylinder block 10 side.

FIGS. 4 and 5 show a state in which the breather plate 25 is mounted in the crankcase 15 of the cylinder block 10. FIG. The breather plate 25 is fitted to the front and rear bearing walls 10c below the cylinder 11, and the top end 25d of the breather plate 25 is applied to the lower end 11a of the cylinder 11 so that the small hole 2g is aligned with the bolt hole 20 and the bolt is inserted. 22, the lower end flange 25 f is applied to the lower surface of the bearing wall 10 c of the cylinder block 10, the small hole 2 h is aligned with the bolt hole 21 and screwed with the bolt 23, and the breather plate 25 is fixed inside the crankcase 15. Is fixed to the bearing wall 24 with the front and rear sandwiched therebetween.

The curved portion 25a of the breather plate 25
The outer wall 1 of the crankcase 15 is located below the lower end opening 16a of the breather passage 16 and goes further downward.
Breather plate 2 with a gap between the inner surface of 0d
5 and the lower end of the outer wall 10d of the cylinder block 10 to form a breathing passage 27 with a space therebetween. The breather passage 16 and the passage are formed from the inside where the crank weight 32 of the crankshaft 30 rotates. 2
7 is divided. In FIG. 4, the crank weight 3
Although the envelope 32a of the rotation locus of No. 2 is shown by a two-dot chain line, the breather plate 25 extends downward to near the lower end of the envelope 32a.

The crankpin 31 of the crankshaft 30
Is located at the center of the front and rear bearing walls 10c and has a crank weight 3 between the crankpin 31 and the front and rear bearing walls 10c.
2 is located (see FIG. 5). Therefore, the breather plate 25 is disposed outside the rotating crank weight 32, and the connecting rod 33 having a large end pivotally connected to the crank pin 31 and connected to the piston 34 is connected to the upper end of the breather plate 25 together with the rotation of the crankshaft 30. It does not pass through the notch 25c so as not to interfere (in FIG. 4, the envelope 33a of the connecting rod 33 is indicated by a two-dot chain line).

The breather plate 25 is attached below the breather passage 16 as described above, and the breather plate 26 is attached below the breather passage 17 in the same manner.
The shape is slightly different from the breather plate 25 as shown in FIG. In other words, the breather plate 26 has a concave portion 26b in which the rear edge of the curved portion 26a is slightly cut out in order to secure a mounting portion for the oil pan, and has a lower end flange 26b.
The rear side of c is shorter. Notch 2 at center of upper end
Other points such as having a 6d
Is the same as

The breather plate 26 is attached below the breather passage 17 in the same manner as the breather plate 25, and separates the crankcase 15 from the crankshaft 30 to secure a passage 28 leading to the breather passage 17.

The breathing structure of this embodiment is configured as described above. When the crankshaft 30 rotates counterclockwise in FIG.
Even if 2 stirs the splash oil in the crankcase,
Since the oil return paths 18 and 19 and the breather paths 16 and 17 are not provided in the scraping direction, the scooped oil does not enter the breather path, and the oil generated by the crank weight 32 rotating at a certain high speed. The curtain is also blocked by breather plates 25 and 26 which are suspended to the vicinity of the lower end of the envelope 32 a of the crank weight 32, and the passage 2 leading to the breather passages 16 and 17.
7, 28 are always reserved.

Therefore, the space above the cylinder head for accommodating the valve operating mechanism and the crankcase 15 are connected to the breather passage 1.
6, 17 and the passages 27 and 28 ensure the communication state, and the smooth return of the oil passing through the oil return passages 18 and 19 can be maintained by the air release operation.

The breather plates 25 and 26 have cutouts 25c and 26d at the center of the upper end, respectively.
However, since the cutouts 25c and 26d are not located outside the rotation of the crank weight 32, the influence of the oil curtain is small, and the cutouts 25c and 26d also act as breather passages to increase the passage area. I have.

Since the notches 25c and 26d of the breather plates 25 and 26 are provided for the connecting rods, the whole structure is compact.

Further, the breather plates 25, 26 have their upper ends fixed to the lower ends 11a, 14a of the cylinders 11, 14, and their lower ends fixed to the vicinity of the lower end of the outer wall 10d of the cylinder block 10. The strength of the block 10 is improved.

[0034]

According to the present invention, a breather plate can be provided below the lower end opening of the breather passage so that a passage leading to the breather passage can be secured, so that the breather passage is prevented from being blocked by an oil curtain caused by rotation of the crank weight. Thus, the return of oil through the oil return path can always be maintained smoothly.

[Brief description of the drawings]

FIG. 1 is a sectional view of an engine showing a conventional breathing structure.

FIG. 2 is a top view of a cylinder block according to one embodiment of the present invention.

FIG. 3 is a bottom view of the same.

FIG. 4 is a cross-sectional view including the IV-IV cross section of FIG. 2 and FIG. 3 and other members.

FIG. 5 is an enlarged bottom view of the main part.

FIG. 6 is a front view of a breather plate.

FIG. 7 is a side view of the same.

FIG. 8 is a bottom view of the same.

FIG. 9 is a front view of another breather plate.

FIG. 10 is a side view of the same.

FIG. 11 is a bottom view of the same.

[Explanation of symbols]

10 ... cylinder block, 11 ... cylinder, 12 ... cylinder,
13 ... cylinder, 14 ... cylinder, 15 ... crankcase, 16
... breather path, 17 ... breather path, 18 ... oil return path, 19 ... oil return path, 20 ... bolt hole, 21 ... bolt hole, 22 ... bolt, 23 ... bolt, 25 ... breather plate,
26 ... breather plate, 27 ... passage, 28 ... passage, 30 ... crankshaft, 31 ... crankpin, 32 ... crankshaft, 33 ... connecting rod, 34 ... piston, 35 ... balancer shaft, 36 ... balancer shaft, 40 ... oil pan .

Claims (2)

(57) [Claims] 1. An internal combustion engine in which an oil return path and a breather path are formed on opposite sides of a cylinder , respectively, and a crank weight rotates in a direction to descend on the breather path side. A breather plate extending downward along the inner surface of the crankcase is provided, a passage leading to the breather path is formed between the breather plate and the inner surface of the crankcase , and interference with a connecting rod is formed at an upper end of the breather plate. To
A breathing structure for an internal combustion engine, characterized in that a cutout portion that opens to the breather path is formed . 2. An internal combustion engine in which an oil return path and a breather path are formed on opposite sides of a cylinder , respectively, and a crank weight rotates in a direction to descend on the breather path side. A breather plate extending downward along the inner surface of the crankcase is provided, and a passage leading to the breather path is formed between the breather plate and the inner surface of the crankcase, wherein the upper end of the breather plate has a lower end of a cylinder. Solid
And the lower end is near the lower end of the outer wall of the cylinder block.
A breathing structure for an internal combustion engine, which is fixed .