JPH068247Y2 - Engine breather device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an engine breather device for preventing blow-out from an oil return hole formed in a breather plate.

[Problems to be solved by conventional techniques and devices] Generally, a four-cycle engine is equipped with a breather device for guiding blow-by gas leaking into the crank chamber to an intake system for re-combustion and keeping the crank chamber at a negative pressure. Has been done.

In this type of breather device, in order to separate the mist-like oil contained in the blow-by gas, for example
As disclosed in Japanese Patent Publication No. 7-182212, before introducing blow-by gas to the breather chamber, first it is made to collide with the oil shield plate, and then, it is made to collide with the leaf valve which is in contact with the gas discharge port of the breather plate, After gas-liquid separation, blow-by gas is introduced into the breather chamber.

Further, the blow-by gas flowing into the breather chamber contains a small amount of mist-like oil, and this slight mist-like oil collides with the breather chamber inner wall or the like to be dropped and stay at the bottom of the breather chamber. . Then, the oil retained at the bottom of the breather chamber is returned to the crank chamber through an oil return hole formed in the lower portion of the breather plate when the crank chamber is under negative pressure.

By the way, if the oil return hole is small, it is difficult to efficiently reduce the oil retained in the breather chamber.
On the other hand, if the oil return hole is too large, blow-by gas blows out from the oil return hole to the breather chamber when the pressure in the crank chamber is positive, and the oil retained in the breather chamber is scattered, The liquid separation effect is halved.

For example, in Japanese Utility Model Laid-Open No. 61-155616, the lower part of a retainer plate that regulates the opening of the leaf valve is placed opposite to the oil return hole at a constant interval, and the retainer plate is used to connect the oil return hole. There is disclosed a technique for restricting blow-by gas blown out from the.

However, in the breather device disclosed in this prior art, the lower part of the retainer plate must be extended to the oil return hole side with a certain interval, and the structure of this retainer plate becomes complicated, so that manufacturing and assembly are difficult. It becomes complicated.

Further, since the retainer plate has a structure that also serves as a blowout prevention plate, the shape of this retainer plate causes
The position of the oil return hole is restricted, the degree of freedom in design is restricted, and this becomes an obstacle in simplifying the structure.

Further, since the oil return hole is formed at a constant height from the bottom of the breather chamber, a certain amount of oil is always retained in the breather chamber. When the amount of the retained oil is relatively large, the blow-by gas passing through the breather chamber is easily sucked and the gas-liquid separation effect is halved.

[Object of the Invention] The present invention has been made in view of the above circumstances, has a simple structure, facilitates manufacturing and assembling, and effectively prevents blow-by gas from being blown out from an oil return hole. It is an object of the present invention to provide an engine breather device that can obtain a separation effect.

[Means and Actions for Solving Problems] In a breather device for an engine according to the present invention, a gas discharge port is formed in a breather plate that divides a crank chamber and a breather chamber formed in a breather cover. In addition, in the breather device of the engine in which the oil return hole is bored on the lower side thereof, in the breather cover,
The breather plate is provided with a protrusion in the vicinity of an oil return hole formed therein, and as an example, the protrusion is formed integrally with the breather cover by bending. preferable.

According to this configuration, the blow-by gas that is about to blow out from the oil return hole formed in the breather plate into the breather chamber is regulated by the labyrinth effect at the protrusion near the oil return hole.

Further, the amount of oil retained in the breather chamber is reduced because the protrusion is projected in the breather chamber.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

The drawings show one embodiment of the present invention. Fig. 1 is a front view of a breather device, Fig. 2 is a sectional view taken along line II-II of Fig. 1, and Fig. 3 is a sectional view taken along line III-III of Fig. 1. 4 is a rear view of the breather cover in FIG. 3, FIG. 5 is a perspective view of the breather cover, FIG. 6 is a rear perspective view of the breather plate, and FIG. 7 is a longitudinal sectional view of the engine.

Reference numeral 1 in the drawing is an engine body of an overhead valve (OHV) engine, and a crank chamber 1a and a rocker chamber 1b of the engine body 1 are communicated with each other via a push rod chamber 1d formed in a cylinder block 1c. There is. The mist-like oil in the crank chamber 1a is introduced into the blow-by gas, passes through the push rod chamber 1d and flows into the rocker chamber 1b, and lubricates each valve mechanism of the rocker chamber 1b.

Further, an oil reservoir 3 is defined adjacent to the push rod chamber 1d of the cylinder block 1c via a partition wall 4, and a communication hole 4a is formed in an upper portion of the partition wall 4.

Further, a breather plate 6 is attached to the side surface opening of the oil reservoir 3 via a gasket 5, and a breather cover 8 is attached to the back surface thereof via another gasket 7.
These components 5 to 8 are fastened together to the engine body 1 via bolts (not shown) and the like.

Further, a gas discharge port 6a is formed in one side of the breather plate 6 on the upper side (left side in FIG. 1), and an oil return hole 6b is formed in the center of the lower side. Further, the oil shield plate 9 is brought into contact with the breather plate 6 facing the oil reservoir chamber 3 side, while the breather plate 6 facing the breather chamber 10 side formed by the breather cover 8 is The leaf valve 11 and a retainer plate 12 that regulates the opening of the leaf valve 11 are in contact with each other, and the components 9, 11 and 12 are fastened together to the breather plate 6 via rivets or the like. There is.

Further, the oil shield plate 9 is provided with an oil shield portion 9a opposite to the gas discharge port 6a formed in the breather plate 6 at a constant interval and a bottom portion of the oil reservoir chamber 3. The oil return passage 1e is provided to face the oil return passage 6e, and the oil return hole 6b is provided.
And a blowback preventing portion 9b disposed on the upper part of the are integrally formed by bending. The oil return passage 1e communicates with the crank chamber 1a.

Further, the leaf valve 11 is the breather plate 6
The gas exhaust port 6a is abutted against the gas exhaust port 6a, and the gas exhaust port 6a is opened and closed according to the pressure fluctuation of the crank chamber 1a.

On the other hand, at the center of the lower portion of the breather cover 8, a protrusion 8a protruding toward the breather chamber 10 is integrally formed by bending by means such as drawing. Further, a flat receiving surface 8b of the protrusion 8a facing the breather plate 6 has an oil return hole 6b formed in the breather plate 6.
Being close to.

Further, the breather pipe 13 communicating with the intake system via an air cleaner (not shown) is provided at the other side of the upper portion of the breather cover 8 (on the right side in FIG. 1), that is, at a position opposite to the gas discharge port 6a with the center line interposed therebetween. Are connected.

Next, the operation of the embodiment having the above configuration will be described.

When the crank chamber 1a of the engine body 1 has a positive pressure, the mist-like oil floating in the crank chamber 1a is guided by the blow-by gas to flow into the rocker chamber 1b, and lubricates each valve mechanism in the rocker chamber 1b. To do.

On the other hand, part of the blow-by gas flowing through the push rod chamber 1d flows into the oil sump chamber 3 through the communication hole 4a formed in the partition wall 4 that partitions the push rod chamber 1d. Then, the blow-by gas that has flowed into the oil storage chamber 3 collides with the oil shield 9a of the oil shield plate 9, and the mist-like oil contained in this blow-by gas is dropped.

Next, the blow-by gas bypassing this oil shield 9a is
The mist-like oil contained in the blow-by gas is further dripped by being guided to the gas discharge port 6a formed in the breather plate 6 and colliding with the leaf valve 11 in contact with the gas discharge port 6a. It

Then, the gas-liquid separated blow-by gas pushes open the leaf valve 11, flows into the breather chamber 10 formed by the breather cover 8, and the retainer plate 12 that regulates the opening degree of the leaf valve 11; Upon colliding with the inner wall surface of the breather cover 8, a small amount of mist-like oil contained in the blow-by gas is further dropped.

The oil droplets in the oil reservoir chamber 3 and the breather chamber 10 are retained at the bottoms of the chambers 3 and 10.

Further, the blow-by gas completely gas-liquid separated in the breather chamber 10 bypasses the retainer plate 12 and is circulated to an air cleaner (not shown) through a breather pipe 13 connected in a direction opposite to the retainer plate 12 and is sucked. It is reburned through the system.

On the other hand, when the crank chamber 1a has a negative pressure, the gas outlet 6a formed in the breather plate 6 is closed by the leaf valve 11. Also, the breather chamber 10
The oil stored in the oil reservoir chamber 3 is sucked into the oil reservoir chamber 3 through an oil return hole 6b formed in the lower center of the breather plate 6. Then, the oil sucked into the oil sump chamber 3 and the oil retained in the oil sump chamber 3 pass through the oil return passage 1e formed in the bottom of the oil sump chamber 3 and It is returned to the crank chamber 1a.

By the way, when the crank chamber 1a has a positive pressure, the mist-like oil in the crank chamber 1a tries to blow out from the oil return passage 1e to the oil sump chamber 3, but the blowback preventing portion 9b is opposed to the oil return passage 1e. Since it is provided, the labyrinth effect does not cause a pressure difference, and the blowout from the oil return passage 1e is prevented.

Similarly, oil tries to blow out from the oil return hole 6b of the breather plate 6 to the breather chamber 10, but the oil return hole 6b receives the protrusion 8a bent on the breather cover 8. Since the surfaces 8b are close to each other, a pressure difference does not occur, and blowing is effectively prevented.

As a result, the oil reservoir chamber 3 and the breather chamber 10
Only the blow-by gas is circulated to the intake system because scattering of the oil retained in the air is prevented from being blown out.

Further, since the protruding portion 8a of the breather cover 8 projects into the breather chamber 10, the amount of oil staying at the bottom of the breather chamber 10 decreases, and the oil can be efficiently returned to the crank chamber 1a. You can

Further, since the protrusion 8a is bent and formed in the lower portion of the breather cover 8, not only can the direction at the time of assembling be discriminated, but also when trying to reversely assemble, the protrusion 8a interferes with the retainer plate 12. Therefore, erroneous assembly is eliminated and the efficiency of assembly can be improved.

In addition, since the protrusion 8a is integrally bent from the breather cover 8, the number of parts can be reduced, manufacturing and assembling can be facilitated, and manufacturing cost can be reduced.

The present invention is not limited to the above embodiment, and for example, a protrusion may be attached to the breather cover later.

[Effects of the Invention] As described above, according to the present invention, the breather plate that divides the crank chamber and the breather chamber formed in the breather cover is provided with the gas discharge port and the lower side thereof. In the case where the oil return hole is formed in the breather cover, the breather cover is provided with a protrusion close to the oil return hole formed in the breather plate. Blow-off is effectively prevented, and a high gas-liquid separation effect is obtained.

Further, since the protrusion provided on the breather cover is projected into the breather chamber, the amount of oil retained in the breather is smaller than that of the conventional one, and the oil can be efficiently returned. Therefore, the oil staying in the breather chamber is less likely to be sucked by the blow-by gas flowing into the intake system, and only the blow-by gas flows through the intake system, so that the gas-liquid separation effect is further improved.

Further, the degree of freedom in design is increased as compared with the conventional one in which the retainer plate also serves as the blowout prevention plate, and the structure can be simplified accordingly.

On the other hand, as described in claim 2, if the protrusion is integrally formed with the breather cover by bending, manufacturing becomes easy, and reverse assembly is effectively prevented. You can

[Brief description of drawings]

The drawings show one embodiment of the present invention. Fig. 1 is a front view of a breather device, Fig. 2 is a sectional view taken along line II-II of Fig. 1, and Fig. 3 is a sectional view taken along line III-III of Fig. 1. 4 is a rear view of the breather cover in FIG. 3, FIG. 5 is a perspective view of the breather cover, FIG. 6 is a rear perspective view of the breather plate, and FIG. 7 is a longitudinal sectional view of the engine. 1a ... crank chamber, 6 ... breather plate, 6a ...
… Gas outlet, 6b …… Oil return hole, 8 …… Breazer cover, 8a …… Projection, 10 …… Breazer chamber.

Claims (2)

[Scope of utility model registration request] Claim: What is claimed is: 1. An engine in which a breather plate that defines a crank chamber and a breather chamber formed in a breather cover is provided with a gas discharge port, and an oil return hole is provided below the gas discharge port. In the breather device of
A breather device for an engine, wherein the breather cover is provided with a protrusion that is close to an oil return hole formed in the breather plate. 2. The breather device for an engine according to claim 1, wherein the protrusion is integrally formed on the breather cover by bending.