JPS6339368Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a lubricating device for an OHV engine that is capable of lubricating the rocker chamber of the OHV engine.

[Problems that conventional technology and ideas try to solve]

Generally, some OHV (overhead valve) engines are equipped with a forced lubrication device that pumps lubricating oil to lubricate the rocker arm, rocker shaft, etc. in the rocker chamber. On the other hand, it is expensive and uneconomical to equip a forced lubrication system, especially in a single-cylinder OHV engine, so a ventilation passage connecting the crank chamber and the rocker chamber is provided to ventilate the breather device due to pressure fluctuations in the crank chamber. Some devices are designed to supply lubricating oil in the form of a mist to the rocker chamber for lubrication.

Japanese Utility Model Publication No. 58-15610 proposes a conventional technique related to a lubricating device for a single-cylinder OHV engine as described above. In this conventional technology, a tappet chamber is formed on the outer surface of the crankcase, a breather device is mounted facing this tappet chamber, and the breather device and the crank chamber communicate with each other through an oil return hole. The rocker chamber located above the head is communicated with the rocker chamber through a ventilation passage, and the rocker chamber and the tapepet chamber are communicated with each other through a push rod insertion hole.

However, in a lubricating device having such a configuration, it is necessary to separately provide a push rod insertion hole and to form a long ventilation passage that communicates the crankcase and the rocker chamber. In particular, the ventilation passage is provided within the peripheral wall of the cylinder portion of the crankcase and within the inner wall of the cylinder head, resulting in poor manufacturing efficiency. Furthermore, since the push rod insertion hole opens at the top of the cylinder head, lubricating oil can easily flow directly into the cylinder head.

Further, in Japanese Utility Model Application Publication No. 55-149508, the crank chamber and the rocker chamber are communicated through a push rod chamber, and the opening of the breather passage communicating with the breather chamber is connected to the rocker chamber through the opening of the push rod chamber. A technique is disclosed in which excess lubricating oil that has flowed into the rocker chamber is recirculated from the push rod chamber to the crank chamber by opening at a position apart from the push rod chamber, thereby suppressing the flow into the breather chamber. .

However, in this prior art, the opening of the breather passage is opened laterally at the upper side of the rocker chamber, and the breather passage extends directly downward from the opening. When blow-by gas flows into the breather passage, the lubricating oil that collides with the wall of the breather passage and separates drops directly into the breather chamber.
Accordingly, there is a problem in that the lubrication efficiency of the valve train in the rocker chamber is reduced.

Furthermore, in the above-mentioned prior art, the lubricating oil remaining in the breather chamber is returned directly to the crank chamber through a small hole drilled in the bottom of the breather chamber. This means that the lubricating oil remaining in the breather chamber is prone to flow back from the crank chamber to the breather chamber through the small hole when positive pressure is applied, i.e., a so-called blowout occurs. Some of the lubricating oil scattered by the blowout is released into the atmosphere through the exhaust port.
There are problems in that the consumption of lubricating oil increases and that the area around the engine becomes dirty. Furthermore, if the exhaust port is connected to the intake system, there are problems in that the combustion of the lubricating oil in the blow-by gas leads to a decrease in output and a deterioration of exhaust emissions.

[Purpose of invention]

This idea was made in view of the above circumstances.
It is possible to reliably lubricate the valve train in the rocker chamber of an OHV engine, to prevent the lubricating oil in the rocker chamber from flowing directly into the breather chamber, and to have a simple structure that is easy to manufacture. Moreover, not only can the entire engine be made more compact, but also lubricating oil can be used economically, and it is also possible to effectively prevent contamination around the engine, decrease in engine output, and deterioration of exhaust emissions. The purpose is to provide a lubricating device for OHV engines.

[Means and actions for solving the problem]

In order to achieve the above-mentioned problems, the present invention has a breather chamber in which a breather device is inserted in the side of the cylinder barrel of the crankcase. In the lubricating device for an OHV engine, the locker chamber and a crank chamber formed in the crankcase are communicated via a push rod chamber, and the opening of the breather passage opens into the locker chamber. To,
A ventilation passage extending to a position apart from the opening of the push rod chamber that opens into the rocker chamber and having a vent opening downward to the rocker chamber is connected to the crankcase. A compartment is formed with a small chamber that communicates with the
This small chamber communicates with the breather chamber through an oil return hole, and the lubricating oil that collides with the inner wall of the vent of the ventilation passage and is separated is because this vent opens downward. It is dripped into the Rotsuka chamber.

Moreover, pressure fluctuations in the crank chamber are absorbed by the small chamber, thereby preventing blowouts.

〔Example〕

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

1 to 3 relate to an embodiment of the present invention, in which FIG. 1 is a sectional view at right angles to the axis of an OHV engine, FIG. 2 is a sectional view of a portion where a breather passage is formed,
FIG. 3 is a sectional view taken along the line A--A in FIG. 2.

(Configuration) In these figures, code 1 is the OHV engine;
2 is a crankcase integrally formed with a cylinder barrel; 3 is a cylinder head; one side of the crankcase 2 and the cylinder head 3 is partitioned with a crank chamber 4 provided on the lower side of the crankcase 2; , and a push rod chamber 5 which communicates with each other in the longitudinal direction and opens at the upper part of the cylinder head 3 is formed.

The opening of the push rod chamber 5 is formed in a tapered shape that widens upward so that the lubricating oil on the upper surface of the cylinder head 3 can easily return to the push rod chamber 5. Further, a push rod 6 is inserted into the push rod chamber 5 and disposed therein.

Furthermore, a tappet 7 is slidably inserted and supported in a hole bored in the crankcase 2 at a lower position of the push rod chamber 5, and the lower end of the tappet 7 is disposed in the crank chamber 4. It is in contact with the cam 8. The upper end of the tappet 7 is formed in a concave shape and projects into the push rod chamber 5, and the lower end of the push rod 6 is fitted into the recess of the tappet 7.

On the other hand, the upper end of the push rod 6 is formed in a convex shape, and this convex part is fitted into a concave part of the rocker arm 9 and supported. Moreover, this locking arm 9 is pivotally supported by a locking shaft 10,
Valve 1 is located at the opposite end of the push rod 6 above.
1 is in contact with the tip. This valve 11
is biased against the valve seat by a spring 12, and the exhaust (or intake) passage 13 is opened and closed by the rotational pressure of the spring 12 and the rocker arm 9.

Further, on the upper part of the cylinder head 3, a rocker arm 9, a rocker shaft 10, a valve 11,
A locking cover 14 is attached that surrounds the spring 12 and the opening of the push rod chamber 5, and the locking cover 14 and the cylinder head 3 are connected to each other.
A rocker chamber 15 is formed with the upper surface.

Further, on one side of the crankcase 2, a breather chamber 17 is formed, which is separated from the crank chamber 4 formed in the crankcase and the push rod chamber 5, and has an opening 16 on the side. A breather device 18 is attached to this opening 16. A breather pipe 20 communicating with an air cleaner 19 is connected to this breather device 18 .

Further, a breather passage 21 is formed on one side of the crankcase 2 and the cylinder head 3 to communicate the breather chamber 17 and rocker chamber 15. This breather passage 21 is arranged parallel to and separated from the push rod chamber 5, and has an opening 2 in the locker chamber 15 provided on the upper surface of the cylinder head 3.
2 is open. Moreover, in this opening 22,
A ventilation path 23 is connected.

This ventilation passage 23 is formed by abutting a partition plate 24 having a U-shaped cross section and flanges formed on both sides from the inner wall of the rocker chamber 15 on the opening 22 side to the upper part on the valve 11 side. There is. That is, the breather passage 21 is formed to extend along the inside of the rock cover 14, and the vent hole 25 is
It opens downward at a position spaced apart from the opening of the push rod chamber 5.

On the other hand, at the bottom of the push rod chamber 5, a sufficiently large vent hole 26 is formed by a cast hole for communicating the push rod chamber 5 and the crank chamber 4.

Further, an oil return hole 27 is formed at the bottom of the breather chamber 17 to communicate the breather chamber 17 with a small chamber 2a formed in the crankcase 2. The diameter of the oil return hole 27 is formed to be sufficiently smaller than the breather passage 21 in order to prevent backflow (so-called blowout) of lubricating oil.

Furthermore, the small chamber 2a is communicated with the crank chamber 4 through a small hole (not shown).

In the figure, reference numeral 28 is the crankshaft, 29 is the connecting rod, 30 is the piston, 31 is the muffler connected to the exhaust passage 13, 32 is the fuel tank, 33 is the carburetor, and 34 is the lower part of the crankcase 2. 35 indicates an oil level detector attached to the lubricating oil fill port.

(Operation) The operation of the OHV engine lubrication system configured as described above will be explained below.

When the engine starts, the crank chamber 4 is filled with mist-like lubricating oil, and this mist-like lubricating oil
The ventilation action of the breather device 18 accompanying pressure fluctuations in the crankcase 4 moves the blow-by gas and reliably guides the rocker chamber 15 from the crank 4 through the ventilation hole 26 and the push rod chamber 5 along the flow shown by arrow a. I can do it.

This allows the rocker arm 9, rocker shaft 10, etc. to be sufficiently lubricated.

Next, the blow-by gas in the rocker chamber 15 is
Flows into the rocker chamber 15 from the vent 25 opening downward along the flow shown in FIG.
Flows into the breather chamber 17 via the breather passage 21,
Further, the air is discharged from the air cleaner 19 through the breather device 18 and the breather pipe.

That is, since the vent port 25 of the vent passage 23 opens downward at a position apart from the opening of the push rod chamber 5, the mist-like lubricating oil does not directly flow into the breather passage 21, and the The lubricating oil that collides with the vent hole 25 and is separated is dripped into the rocker chamber 15. As a result, the valve train provided in the rocker chamber 15 is efficiently lubricated, and the valve train is sufficiently lubricated.

The lubricating oil dropped into the rocker chamber 15 flows down the push rod chamber 5 and lubricates the tappet chamber 7.

On the other hand, the mist-like lubricating oil is transported to the breather chamber 17 and liquefied, and the lubricating oil is transported to the small chamber 2a through the oil return hole 27 formed at the bottom of the breather chamber 17.
is returned to the crank chamber 4 via. At this time, the diameter of the oil return hole 27 is formed with a sufficiently small dimension,
In addition, since pressure fluctuations in the crank chamber 4 are absorbed to some extent by the small chamber 2a, blow-by gas does not flow from the crank chamber 4 to the breather chamber 17 (so-called blow-off), and lubricating oil does not flow back.

As a result, the lubricating oil does not flow out from the breather chamber 17 through the breather device 18 to the intake system such as the air cleaner 19, and it is possible to effectively prevent a decrease in output and deterioration of exhaust emissions due to burning of the lubricant. , lubricating oil can be used economically.

Through the above operations, the rocker arm 9, rocker shaft 10, etc. in the rocker chamber 15 are sufficiently lubricated.
The passage through which the gas flows can be made by using the push rod chamber 5, or by using the breather passage 21 or the ventilation hole 26.
etc. can be formed using cast holes, making it easy to manufacture these and making the entire engine more compact. Furthermore, since the breather passage 21 and the like are formed long, it is possible to improve efficiency in draining lubricating oil from blow-by gas.

In addition, in the above embodiment, the push rod chamber 5
The breather passage 21 only needs to be formed so as to pass through both the cylinder barrel and the cylinder head 3 and to be partitioned from each other, and its position, shape, etc. are not limited to those in the embodiment. Further, the vent hole 26 and the oil return hole 27 only need to communicate with the inside of the crankcase 4.

Furthermore, the oil return hole 27 may be provided with a check valve to prevent the lubricating oil from flowing back. Furthermore, the ventilation passage 23 is connected to the breather passage 2
1, and the vent 25 of this ventilation passage 23 is formed downward in a position spaced apart from the opening of the locker chamber 5 in the push rod chamber 5. For example, the inside of the locker chamber 15 is connected to the opening 22 of the Alternatively, a rock cover provided with a ventilation passage may be formed by casting.

[Effect of idea]

As explained above, according to the present invention, OHV
In an engine, the crank chamber and the locking chamber are communicated through a push rod chamber, and the locking chamber and a breather chamber equipped with a breather device are connected through a breather passage, and an opening in the breather passage opens into the locking chamber. A ventilation path extending and opening at a position apart from the opening of the push rod chamber opening into the rocker chamber is connected to the opening of the push rod chamber, and the crank chamber is filled with the ventilation effect of the breather device due to pressure fluctuations in the crank chamber. Since the mist of lubricating oil is moved to the locking chamber, the valve train can be reliably lubricated, and excess lubricating oil in the locking chamber flows into the push rod chamber and does not flow directly into the breather chamber. You can do it like this.

Furthermore, since the push rod chamber, breather passage, etc. can be formed using cast holes, manufacturing is facilitated, and the entire engine can be made more compact.

Furthermore, since the vent of the ventilation passage opens downward into the rocker chamber, the lubricating oil that collides with the inner wall of the vent and is separated is dripped into the rocker chamber, thereby increasing the lubrication efficiency of the valve train. will improve.

Further, since the breather chamber is communicated with a small chamber communicating with the crank chamber via an oil return hole, pressure fluctuations in the breather chamber are absorbed by the small chamber and flow back from the oil return hole to the breather chamber. So-called ballooning is effectively prevented. As a result, the lubricating oil that remains in this breather chamber is no longer scattered, and only blow-by gas is released to the intake system, etc., which not only improves the reduction in engine output and deterioration of exhaust emissions. , it is possible to reduce lubricant consumption.

Furthermore, the vent of the ventilation passage is opened downward, and the breather chamber is communicated with the crank chamber through a small chamber, so that the amount of lubricant flowing into the breather chamber is small and blow-out is effectively prevented. Therefore, excellent effects such as further improvement of the gas-liquid separation effect in the breather device can be achieved.

[Brief explanation of the drawing]

1 to 3 relate to an embodiment of the present invention, in which FIG. 1 is a sectional view at right angles to the axis of an OHV engine, FIG. 2 is a sectional view of a portion where a breather passage is formed,
FIG. 3 is a sectional view taken along the line A--A in FIG. 2. 1...OHV engine, 2...crank case,
2a... Small chamber, 3... Cylinder head, 4... Crank chamber, 5... Push rod chamber, 6... Push rod, 9... Locker arm, 10... Locker shaft, 14... Locker cover, 15... Locker chamber, 17 ... Breather chamber, 18 ... Breather device, 21 ... Breather passage, 22 ... Opening, 2
3...Vent passage, 25...Vent hole, 26...Vent hole, 27...Oil return hole.

Claims (1)

[Claims for Utility Model Registration] A breather chamber in which a breather device is inserted is formed on the side of the cylinder barrel of the crankcase, and this breather chamber and a rocker chamber provided on the cylinder head are connected via a breather passage. communicated,
Furthermore, in a lubricating system for an OHV engine in which the rocker chamber and a crank chamber formed in the crankcase are communicated via a push rod chamber, an opening of the breather passage that opens into the rocker chamber is provided with a push rod chamber. A ventilation passage extending to a position apart from the opening opening into the rocker chamber and having a vent opening downward to the rocker chamber is connected to the rocker chamber, and a small chamber communicating with the crank chamber to the crankcase. 1. A lubricating device for an OHV engine, characterized in that a small chamber is formed into a compartment, and this small chamber is communicated with the breather chamber through an oil return hole.