JPS62225711A - Lubricating device for engine - Google Patents

Abstract

PURPOSE:To rapidly return excessive lubricating oil to a crank chamber, to reduce an amount of oil consumed, and to prevent reduction of a blow-by gas circulating amount, by a method wherein an oil return passage, adapted to return lubricating oil from a locker arm chamber to a crank chamber, is installed, and a check valve is located in the passage. CONSTITUTION:Lubricating oil is stored in the lower part of a crank case 1, and a splasher 6 is integrally mounted to a cap 4a adapted to connect the large end part of a connecting rod 3, connected to a piston 2, to a piston 4. Through rotation of the splasher 6 along with reciprocating movement of the piston 2, lubricating oil is splashed, and circulates in pipes 11 and 12 to lubricate each part. In this constitution, an oil return passage 25 is formed in the lower end of a containing part 24 into which a push rod 21 is inserted, and a check valve 30, allowing only a flow destined for the crank chamber, is situated in the passage 25. Lubricating oil gathering at the bottom of the containing part 24 is caused to flow through the check valve 30 down to the crank chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to engine lubrication technology, and in particular to a technology that is effective when used in a lubrication device for lubricating the head portion (rocker arm chamber) of a four-stroke engine. Regarding.

[Prior Art] In a four-stroke engine, a lubricating device is used to reduce wear on rotating parts such as the crankshaft and crankbin, and sliding parts such as cylinder walls. A simple structure in which a splasher 6 is fixed to the crankcase 1, and by rotating the splasher 6 around the crankshaft 5, the lubricating oil stored in the oil reservoir at the bottom of the crankcase 1 is scraped up and scattered around. There is a lubrication device.

The above lubrication method alone cannot supply lubricating oil to the valve train of the cylinder head. Therefore, in the lubricating device shown in FIG. 4, the crankcase 1 and the rocker arm chamber 10 are separated into two parts.
Two pipes 11 and 12 communicate, and one pipe 12
A check valve 14 that only allows flow toward the crank chamber is provided in the middle of the process, and by utilizing the phenomenon in which the pressure in the crank chamber pulsates as the piston reciprocates, the gas flows from the crank chamber to the rocker arm chamber to the crank chamber. A gas flow is created, and the oil droplets in the crank chamber are carried along with the gas flow and supplied to the valve train for lubrication.

Furthermore, in the apparatus shown in FIG. 3, a route is provided in which the blow-by gas blown from the combustion chamber to the crank chamber is guided from the pipe 11 through the rocker arm chamber 10 to the conduit 17 to the air cleaner 18 and returned to the combustion chamber.

[Problems to be Solved by the Invention] In the conventional lubricating device described above, the blow-by gas guided to the air cleaner 18 ends up containing lubricating oil. Therefore, if the diameter of the pipe 11 is determined in such a way that the required amount of oil is supplied to the valve train in the low and medium speed range, when the engine shifts to the high speed range, the air cleaner will pass through the conduit 17. The amount of lubricating oil contained in the blow-by gas led to air cleaner 18 increases, and the air cleaner element becomes wet, increasing intake resistance and increasing oil consumption. Further, the amount of lubricating oil contained in the gas passing through the pipe 12 that returns the blow-by gas to the crank chamber also increases as the engine moves to a high-speed rotation region. It has been found that a problem arises in that lubricating oil accumulates in the engine, increasing ventilation resistance and reducing the amount of blow-by gas circulating between the crank chamber and rocker arm chamber.

This invention secures a sufficient amount of oil supplied to the valve train in the low-to-medium speed rotation range in a lubrication system engine using a splasher, and prevents an increase in intake resistance of the air cleaner in the high-speed rotation range. It is an object of the present invention to provide a lubricating device that can reduce oil consumption and prevent a decrease in the amount of blow-by gas circulation in the high-speed rotation region of an engine.

[Means for Solving the Problems] The present invention provides at least two passages connecting the crank chamber and the rocker arm chamber, and one of the passages is provided with a check valve that primarily regulates the flow of gas toward the crank chamber. , by utilizing the phenomenon in which the pressure in the crank chamber pulsates as the piston reciprocates, the pressure in the crank chamber → rocker arm chamber →
In addition to creating a flow of gas in the crank chamber, an oil return passage is provided separately from this passage to return lubricating oil from the rocker arm chamber to the crank chamber, and a check valve is installed in this oil return passage to mainly regulate the flow of oil. It is something.

[Operation] According to the above-described means, even if an excessive amount of lubricating oil is supplied to the valve train in the high-speed rotation region of the engine, the lubricating oil is returned to the crank chamber as quickly as possible through the oil return passage having a check valve. is returned, and the amount of lubricating oil taken out to the air cleaner side and the amount of lubricating oil contained in the gas entering the return side pipe that constitutes the circulation path of blow-by gas are suppressed.

[Embodiment] FIG. 1 shows an embodiment in which the present invention is applied to a lubrication system for a four-stroke engine.

In this embodiment, lubricating oil is stored in the lower part of the crankcase 1, and a splasher 6 is integrally provided with a cap 4a for connecting the large end of a connecting rod 3 connected to a piston 2 to a crank pin 4. There is. When the crank pin 4 rotates around the crankshaft 5 as the piston 2 reciprocates.

The splasher 6 moves in a trajectory as shown by the dashed line A in the figure, and at this time, the tip of the splasher 6 vigorously scrapes up the lubricating oil at the bottom of the crankcase. Then,
The lubricating oil is scattered as oil droplets, fills the crankcase 1, and adheres to the inner walls of the crankshaft 5, crank pin 6, camshaft 20, or cylinder 7, lubricating their rotating and sliding parts. It is now possible to do this.

In addition, in order to lubricate the valve train in the rocker arm chamber 1o, which is constituted by the engine cover 9 attached to the upper part of the cylinder head 8, a pipe 11 consisting of a gas conduit or the like connects the crankcase 1 and the rocker arm chamber 10. and 12 are provided. The ends of each pipe 11 and 12 are metal connecting pipes 13a, 13b and 13c, 13d.
by the crankcase 1 and engine cover 9 respectively.
It is connected to the. A check valve 14 that only allows flow toward the crankcase 1 is provided in the middle of the pipe 12 between the pipes 11 and 12.

Therefore, when the pressure inside the crankcase 1 rises and falls as the piston 2 reciprocates, a pressure difference occurs between the rocker arm chamber 10 and the pipe 1 from the crank chamber.
1 into the rocker arm chamber 10, and then returns to the crank chamber 1 through the pipe 12, a so-called blizzer flow. Following this flow, oil droplets filling the crankcase 1 enter the rocker arm chamber 10 and adhere to the support shaft 16 of the rocker arm 15, etc., to lubricate the valve train.

On the other hand, blow-by gas from the combustion chamber enters into the crankcase 1, and this blow-by gas also enters the rocker arm chamber 10 from the pipe 11 along with the flow caused by the blizzer. The blow-by gas then enters a passage 23 separated by a separation wall 22 formed along a bushing rod 21 that swings the rocker arm 15 according to the lead surface of the cam 20a on the camshaft 20, where the After the lubricating oil in conduit 1 is separated,
7 to the air cleaner 18, and from the air cleaner it passes through the carburetor and enters the combustion chamber. 18a is an air cleaner element.

Furthermore, in this embodiment, an oil return passage 25 is formed in the lower part of the storage part 24 into which the bushing rod 21 is inserted, and a check valve 30 is provided in this oil return passage 25 to allow only flow toward the crank chamber. The lubricating oil separated by the separation wall 22 accumulates at the bottom of the storage portion 24, quickly flows down to the crank chamber through the check valve 30, and is collected.

FIG. 2 shows an enlarged view of the structure of the mounting portion of the check valve 3o.

A through hole 25 serving as an oil return passage is formed in the bottom wall 26 of the cylinder block that separates the housing portion 24 from the crank chamber, and a check valve 30 is inserted into the through hole 25. As shown in the figure, the check valve 30 is composed of a valve body 31 made of soft rubber or the like, and a valve holder 33 that has a pore 32 and holds the valve body 31, and the check valve 30 is constructed of a valve body 31 made of soft rubber or the like, and a valve holder 33 that holds the valve body 31. When the pressure is lower than the crank chamber pressure, the valve body 31 closes the pore 32 and prevents the lubricating oil in the storage portion 24 from flowing down. However, when the pressure on the housing part 24 side becomes higher than the crank chamber pressure, the valve body 31 deforms and opens the pores 32, so that the lubricating oil accumulated at the bottom of the housing part 24 flows through the pores of the valve holder 33. 32 and flows down to the crank chamber.

In the figure, 28a and 28'b are tappets (followers) that are brought into contact with the cams 20a and 20b on the camshaft 20, are moved up and down according to the shape of the cams, and transmit the movement to the bushing rod 21.

In the above embodiment, in addition to the pipes 11 and 12 that connect the crank chamber and the rocker arm chamber 10 and constitute a lubrication path for supplying lubricating oil to the rocker arm chamber 10, the storage section 24 has a separation wall 22. Since the oil return passage 25 with a check valve is provided at the bottom, the amount of lubricating oil taken out to the air cleaner side can be suppressed without affecting the flow rate of gas circulating through the pipes 11, 12.

That is, when the passage 25 having the check valve 30 is provided at the lower part of the storage part 24, the passage 25 can be omitted even if the pipe 12 is omitted.
5 acts as a substitute for this, the gas that carries the lubricating oil is circulated. Therefore, the pipe 12 is omitted and the passage 2
If only 5 is selected, the amount of lubricating oil that returns from the rocker arm chamber 10 to the crank chamber through the passage 25 is not very large in the low speed rotation region, so the lubricating oil flowing down to the lower part of the storage section 24 passes through the passage 25. The lubricating oil quickly enters the crank chamber and does not significantly affect the flow of circulating gas through there, but as the engine moves to high speed rotation, more lubricating oil is supplied to the valve train from pipe 11. Therefore, the amount of lubricating oil that returns to the crank chamber through the passage 25 in the lower part of the storage part 24 increases, and the lubricating oil accumulates in the lower part of the storage part 24. Therefore, there arises a disadvantage that the flow of gas circulating between the crank chamber and the rocker arm chamber becomes poor.

On the other hand, in the above embodiment, since the oil passage 25 is provided in addition to the pipes 11 and 12 constituting the circulation system, the circulating gas is separated by the pipe 12 and the separation wall 2°2. The lubricating oil is returned to the crank chamber through the oil return passage 25. Therefore, even if the engine shifts to a high-speed rotation region and the amount of lubricating oil returning from the rocker arm chamber 10 to the crank chamber increases and accumulates in the lower part of the storage section 24, the amount of lubricating oil returning from the rocker arm chamber to the crank chamber increases. Since the gas passes through the pipe 12, the amount of gas circulated does not decrease.

Furthermore, in the above case, instead of providing the check valve 30 in the passage 25, it is possible to reduce the cross-sectional area of the passage 25 itself. Since the amount of oil flowing down to the chamber is small, when the engine moves to a high speed region, the storage part 24
There is a risk that more and more lubricating oil will accumulate inside the cylinder, making it impossible to separate the lubricating oil from the blow-by gas. On the other hand,
In the above embodiment, since the check valve 30 is provided in the passage 25, the lubricating oil separated by the separation wall 22 quickly flows down to the crank chamber through the check valve 3o, so there is no such fear. .

In the above embodiment, a through hole is formed in the lower part of the storage portion 24 and a check valve 3o is provided therein.
is installed in the storage section 24 instead of being provided in the cylinder block.
A separate pipe is provided to connect the lower part of the engine and the crank chamber.
A check valve that only allows flow toward the crank chamber may be provided on the way to form an oil return passage. In that case, an oil return passage consisting of pores with a small cross-sectional area may be provided in the lower part of the storage portion 24, separate from the oil return passage (pipe) having a check valve.

[Effects] As explained above, the present invention provides at least two passages connecting the crank chamber and the rocker arm chamber, and one of the passages is provided with a check valve that mainly regulates the flow of gas toward the crank chamber, and the piston Utilizing the phenomenon in which the pressure in the crank chamber pulsates as the gas reciprocates, a gas flow from the crank chamber to the rocker arm chamber to the crank chamber is created, and lubricating oil is supplied from the rocker arm chamber to the crank chamber separately from this passage. An oil return passage is provided, and this oil return passage is equipped with a check valve that mainly regulates the flow of oil, so even if excessive lubricating oil is supplied to the valve train in the high-speed rotation range of the engine, The lubricating oil is returned to the crank chamber from the oil return passage as soon as possible, and the amount of lubricating oil taken out to the air cleaner side and the lubricating oil contained in the gas entering the return side pipe that constitutes the blow-by gas circulation path. By suppressing the amount of oil, a sufficient amount of oil is supplied to the valve train in the low and medium speed range, and an increase in air intake resistance in the high speed range is prevented.
This has the effect of reducing oil consumption and preventing a decrease in the circulation amount of blow-by gas in the high-speed rotation range of the engine.

Although the invention made by the present inventor has been specifically explained above based on examples, it goes without saying that the present invention is not limited to the above-mentioned examples, and can be modified in various ways without departing from the gist thereof. Nor. For example, the structure of the check valve is not limited to that of the above-mentioned embodiment (FIG. 2), and various modifications such as one using balls (11 balls) instead of the deformable valve body are possible.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an overhead valve type engine showing an embodiment of the engine lubrication system according to the present invention, and FIG. 2 is a detailed view of the oil return passage in FIG. 1 as viewed from the direction of arrow B. The enlarged sectional view shown in FIG. 3 is a sectional view showing an example of a conventional engine lubricating device. 1...Crankcase, 2...Piston, 4...
... Crank pin, 6... Splasher, 9...
... Engine cover, 10 ... Rocker arm chamber, 1
1, 12... Passage (pipe), 25... Oil return passage, 30... Check valve. Figure 2

Claims (1)

[Claims] (1) An oil reservoir is provided at the bottom of the crankcase, a splasher is attached to the members that make up the crank mechanism, and the lubricating oil in the oil reservoir is scraped up to lubricate each part,
At least two passages are provided connecting the crank chamber and the rocker arm chamber, and one of the passages is provided with a check valve that primarily regulates the flow of gas toward the crank chamber, making use of the pressure difference between the crank chamber and the rocker arm chamber. In an engine lubricating system that circulates gas in the crank chamber and supplies lubricating oil to the valve train along with the flow of this gas, a passage is provided from the rocker arm chamber separately from the passage that constitutes the gas circulation path. A lubricating device for an engine, characterized in that an oil return passage for returning lubricating oil to a crank chamber is provided, and the oil return passage is provided with a check valve that mainly regulates the flow of oil.