JPS6118166Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The invention is particularly applicable to horizontally opposed internal combustion engines.
This invention relates to a lubrication system structure including an oil tappet that is used in an OHV valve mechanism and converts the rotational movement of a cam into a horizontal linear movement, and more specifically to a system that prevents oil from leaking in and around the oil tappet when the engine is stopped.

[Conventional technology]

In a horizontally opposed internal combustion engine, as shown in FIG. 1, pistons 4 are horizontally connected to the left and right sides of a crankshaft 1 via a connecting rod 2 and a piston pin 3, and the pistons 4 are connected to a horizontally oriented cylinder 5. It is inserted inside and moves back and forth. Further, a camshaft 6 is provided under the crankshaft 1, and oil tappets 7 are installed on the left and right sides of the camshaft 6, and a cam 10a of the camshaft 6 is inserted into the tappet body 8 by inserting the tappet body 8 into the tappet insertion hole 9 on the crankcase side. The oil tappet 7 is connected to the opposite side of the rocker arm 12 from the valve 13 via a push rod 11 extending substantially horizontally, and as the oil tappet 7 and the push rod 11 move, The valve 13 is configured to open and close by swinging the rocker arm 12.

Regarding oil tappets, for example, the one described in Japanese Patent Publication No. 52-24168 is known, and the conventional oil tappet that is the subject of the present invention is detailed in Figure 2. A plunger 14 is movably inserted into the cylindrical tappet body 8, and an annular oil injection groove 15 is formed at a predetermined position on the outer periphery of the tappet body 8, and an oil injection hole is formed in the groove 15. An annular oil passage 19 is formed in the crankcase around the tappet body 8 and communicated with the main oil passage 18. In addition, a pressure chamber 20 is provided between the plunger 14 and the tappet body 8.
A ball check valve 21 is provided between the pressure chamber 20 and the oil chamber 17, and a plunger spring 22 biases the plunger 14 within the pressure chamber 20, causing the plunger 14 to move oppositely to the pressure chamber 20. One end of the push rod 11 makes spherical contact with the push rod seat 23 on the side.

In this way, when the tapepet body 8 is pushed during the lift by the cam 10a, the ball check valve 2
1 is closed to generate high oil pressure in the pressure chamber 20, and the high oil pressure in the pressure chamber 20 integrates the tappet body 8 and the plunger 14 to move the push rod 11. Also, when not lifting, plunger spring 2
2 increases the volume of the pressure chamber 20 and reduces its oil pressure, thereby opening the ball check valve 21 and appropriately replenishing the pressure chamber 20 with oil from the oil chamber 17. When the tapepet body 8 reciprocates during such lift and non-lift times, each time the oil injection groove 15 having the oil injection hole 16 matches the annular oil passage 19, the oil pump pumps the annular oil through the main oil passage 18. The oil forced into the passage 19 is injected into the oil chamber 17 through the oil injection hole 16.

[Problem that the invention attempts to solve]

By the way, the lubrication system including the oil tappet is the third one.
As shown in the figure, an oil passage 28 having an oil filter 25, a drain back valve 26, and an oil pump 27 communicates with the main oil passage 18 at the same height as the oil tappet 7 from the oil pan 24 in the lower part. From there, the journal 6a of the camshaft 6 and the journal 1a of the crankshaft 1 located at a higher position are communicated with passages 29 and 30, respectively, to supply oil.

Therefore, when the journal parts 1a and 6a of the crankshaft 1 and camshaft 6 are opened to the atmosphere when the engine is stopped and air is sucked in from there, the main oil tappet 7 is inserted into the gap between the tappet insertion hole 9 and the tappet body 8. A force corresponding to the head difference between the oil passage 18 and the journal 1a is applied,
This allows the oil to escape from the gap by overcoming the surface tension of the oil. Then, the oil in the oil chamber 17 of the plunger 14 also flows into the passage 18.
Alternatively, air enters there through the gap between the push rod seat 23 and the tappet body 8, and when the engine is restarted, the air in the oil chamber 17 is sucked into the pressure chamber 20, causing the valve to close. This is the cause of the seating noise.

[Means for solving problems]

This invention was developed to solve these problems, and the oil pumped from the lower oil pan by the oil pump is passed through the main oil passage to the oil tappet and camshaft installed horizontally on the crankcase side. and an oil supply system from the main oil passage to the oil tappet side, and an oil supply system to the journal portion of the camshaft and crankshaft, in the case where the oil is supplied to the journal portion of the crankshaft located higher than this. A check valve is provided in the oil supply system to the journal portion of the camshaft and crankshaft to prevent air from entering the oil tappet when the engine is stopped, and the oil passage in and around the oil tappet is The present invention provides a lubrication system structure including an oil tappet that prevents oil from leaking.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. First, the first part of the present invention is shown in Figure 4.
In this embodiment, a main oil passage 18' is installed below the oil tappet 7, and this passage 18' communicates with the annular oil passage 19 side of the oil tappet 7 through a passage 31.
Further, the passage 18' communicates with the journals 1a and 6a of the camshaft and crankshaft through a passage 32 to form a separate supply system, and this passage 32 is provided with a check valve 33.

With this configuration, during engine operation, the main oil passage 18' is connected to the oil tappet 7 through the passage 31, and the camshaft and crankshaft journals 1a and 6a are connected separately through the passage 32 while opening the check valve 33. oil will be supplied to. When the engine stops, the oil pump 27 also stops pumping oil, which closes the check valve 33 and prevents air from entering the passage 32 from the camshaft and crankshaft journals 1a and 6a, which are open to the atmosphere. do. On the other hand, at this time, the drain back valve 26 on the oil pan 24 side is closed to prevent oil from dropping, and thus the oil tappet 7 and the main oil passage 1 between both valves 26 and 33 are closed.
Oil is secured at 8'.

Further, since both ends of the lubrication system including the oil tappet 7 are closed by the valves 26 and 33, the oil tappet 7 has the journal 1a of the crankshaft 1.
No force is applied due to the head difference between the tappet insertion hole 9 and the main oil passage 18', and therefore the gap between the tappet insertion hole 9 and the tappet body 8 is kept closed due to oil surface tension, and the oil from this gap is kept closed. Therefore, no leakage and no air leakage into the oil chamber 17 occurs.

Next, according to a second embodiment of the present invention shown in FIG. 5, a main oil passage 18 is provided at the same position as the oil tappet 7 as in the conventional case, but from this passage 18 a journal 1 of a camshaft and a crankshaft is provided.
Check valves 33 are provided in the middle of the passages 29 and 30 to a and 6a, respectively. As a result, as in the first embodiment, when the engine is stopped, the check valve 33 closes and the passage 2
9 and 30 to prevent air from entering, and also close the drain back valve 26 to prevent oil from dropping into the oil pan 24.
Oil is ensured without leaking into the oil tappet 7 and the main oil passage 18 around it.

[Effect of idea]

In this way, according to the present invention, when the engine is stopped, air does not enter the oil tappet 7, so the valve seating noise is no longer generated, and then the oil tappet 7
And because oil is secured around it,
At the same time as restarting, the oil pressure increases and the oil tappet 7
The engine immediately operates normally, which prevents wear and seizure of various parts due to lack of oil during startup. Particularly at low temperatures, it is difficult to apply hydraulic pressure to the oil tappet 7 due to the viscous resistance of the oil, but this can be resolved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a horizontally opposed internal combustion engine to which the present invention is applied, Fig. 2 is a sectional view showing an example of a conventional oil tappet, and Fig. 3 is a perspective view showing the same lubrication system in three dimensions. , FIG. 4, and FIG. 5 are diagrams showing the lubrication systems of the first and second embodiments of the present invention, respectively. 1a...Crankshaft journal, 6a...Camshaft journal, 7...Oil tappet, 1
8, 18'... Main oil passage, 24... Oil pan, 27... Oil pump, 29, 30, 3
1, 32... passage, 33... check valve.

Claims (1)

[Scope of utility model registration request] A system that supplies oil pumped up by an oil pump from the lower oil pan to the oil tappet installed horizontally on the crankcase side, the camshaft, and the crankshaft journal located higher than this via the main oil passage. , branching the main oil passage into an oil supply system to the oil tappet side and an oil supply system to the journal portions of the camshaft and crankshaft,
A lubrication system structure including an oil tappet, characterized in that the oil supply system to the journal portions of the camshaft and crankshaft is provided with a check valve to prevent air from entering the oil tappet when the engine is stopped.