JPS61182406A - Lubricator for 4-cycle engine - Google Patents

Abstract

PURPOSE:To prevent the cut-off of oil feeding and permit the certain lubrication by separately arranging an oil chamber behind a crank chamber and preventing the stirring of oil and the imbalance of weight and feeding oil into each part of an engine by a pump. CONSTITUTION:When a piston 23 moves vertically with the start of an engine, the positive and negative pressure variation is repeated in a crank chamber 12. Then, a unidirectional valve 16 is opened and closed, and the oil in the crank chamber 12 is discharged into an oil chamber 13 through a communication hole 15. Therefore, in the stationary state, the oil surface B in the oil chamber 13 is set above the initial oil surface A. Therefore, oil exhaustion in a pump 18 is hardly generated. While, in the stationary state, the oil surface C in the crank chamber 12 is set lower than a crank-shaft 31. Therefore, oil is not stirred by the crankshaft 31. The oil in the oil chamber 13 is supplied into the crank chamber 12 and a cam chamber 20 through a feeding passage 19.

Description

[Detailed description of the invention]

FIELD OF APPLICATION ON C'AI] The present invention relates to a lubrication device for a four-stroke engine. C. Conventional technology] In conventional four-stroke engines, the lower part of the crank chamber for lubricating the valve train and cylinder sliding surfaces is made to protrude downward to form an oil reservoir, and an oil pump is placed there. The oil pump is designed to supply oil to the required parts within the engine. However, in an engine having such a structure, there is a problem in that the engine body protrudes downward, making it difficult to make the engine compact, especially in the vertical direction. Therefore, as an example of a 4-stroke engine that is designed to be more compact in the vertical direction, the American ``Dirt Bike Magazine J1''
The engine shown in Fig. 1 is described in the September 19983 issue. This engine uses the pressure fluctuations in the crank chamber 2 caused by the up and down movement 117 of the piston l to drain the oil in the crank chamber 2. The clutch/cam chain chamber 31C, which is provided in 1 liter contact with the side of the crank chamber 20, is moved, and the oil in the clutch/cam chain chamber 3 is scooped up by the cam chain 4 and moved to a predetermined location. It is designed to lubricate the system and cylinder sliding surfaces. [Problems to be solved by the invention] However, in the four-stroke engine with the above configuration,
(a) Since the clutch/cam chain chamber 3 is used as an oil chamber, an oil agitation phenomenon occurs due to the cam chain and clutch (not shown) chain, resulting in an increase in oil temperature and a decrease in engine output; (b) Also, oil The chamber is on the side of the crank chamber.

[Laterally with respect to the IL body]
When the oil level is different as shown in Figure 1 when the engine is running, the weight balance is unfavorable (Q)
Oil in the oil chamber is supplied to various parts of the engine by scraping up the cam chain 4, and when the vehicle is tilted, there is a risk that the oil will be below the cam chain 4, in which case the oil will run out. There are disadvantages such as smooth lubrication not being achieved. The present invention has been made in view of the above-mentioned circumstances.It aims to make the engine more compact, prevents oil temperature rise and engine output reduction due to oil agitation, and provides good weight balance even when the engine is running. Moreover, it is an object of the present invention to provide a lubricating device for a four-stroke engine that can reliably supply oil to each required part within the engine even when the vehicle body is tilted. Means for Solving Problem c] In order to achieve the above object, the present invention includes a crank chamber which is defined in a sealed manner at the bottom of the cylinder and which repeatedly undergoes positive and negative pressure fluctuations as the piston moves up and down. , an oil chamber that is independently provided at the rear of the crank chamber and communicates with the crank chamber through a communication hole, and an oil chamber that is interposed in the communication hole to allow oil to flow only toward the empty oil chamber side of the n1 crank chamber. an oil pump that is installed in the oil chamber and supplies the oil in the oil chamber to the cam chamber and the crank chamber through an oil supply path; The crankshaft is configured to include a balancing hole that is opened and closed to connect the crank chamber to the outside when opened. [Example] The following is part 1 of the present invention! An example of winding will be explained with reference to FIGS. 2 and 3. FIG. 2 shows a schematic configuration of a carrot equipped with a lubricating device according to the present invention, and the reference numeral 11 in the figure is a cylinder, and a crank chamber 12 is defined in the lower part of this cylinder 11 in a sealed state. An oil chamber 3 is defined at the rear of the crank chamber 12 (rearward C with respect to the vehicle body). The oil chamber 13 is defined independently from the crank chamber 12, and is provided through a communication hole 15 passing through the lower part of the partition wall 14 between the crank chamber 12 and the oil chamber 13.
It communicates with the crank chamber 12. The communication hole 15 is provided with a one-way valve 16 that only allows oil to flow from the crank chamber 12 to the oil chamber 13. The one-way valve 16 has a structure in which the upper end of a plate-shaped valve body 17 is screwed from the oil chamber 13 side so as to close the communication hole 15, and functions as a one-way valve by the elastic action of the valve body 17 itself. It is. Further, an oil pump 18 is housed in the oil chamber 13, and the oil discharged from the oil pump 18 is sent to a required location in the crank chamber 12 and a required location in the cam chamber 20 via an oil supply path 19. It is now possible to 9% 2) is an oil return passage, through which the oil in the cam chamber 20 is directly returned to the oil chamber 13 6 On the other hand, numeral 22 is a balancing passage for communicating the inside of the crank chamber 12 with the oil return passage 2). This hole 22 is provided so as to penetrate the side wall of the cylinder 7, and is opened and closed by the vertical movement of the piston 23. Furthermore, the balancing hole 22 is provided in an inclined state so that the oil chamber 13 side is downward in order to facilitate the flow of oil in the crank chamber 12 to the oil chamber 13 side. Note that 24 indicates a carburetor, and 25 indicates a breather hole of the engine. Next, we will explain the operation of the lubrication system configured as described above.A required amount of oil is injected into the engine body in advance, and the middle figure in Figure 2 represents the oil level when the engine is stopped. There is. When the piston 23 moves up and down as the engine starts, the pressure inside the crank chamber 12 repeats positive and negative pressure fluctuations. The one-way valve 16 is opened and closed in accordance with this pressure fluctuation,
The oil in the crank chamber 12 is discharged into the oil chamber 13 through the communication hole 15 together with breathing gas. As a result, the oil in the crank chamber 12 is gradually transferred to the oil chamber 13 side, and in a steady state, the oil level in the oil chamber 13 is equal to or higher than the initial oil level A, as shown by B in FIG.
) 4 will be on the upper side. Therefore, when the oil pump 18 runs out of oil, it can reliably supply oil to the necessary parts of the engine. On the other hand, in the steady state, the oil level in the crank chamber 12 is as shown by C in the fX2 diagram. crankshaft 31
It will be lower. Therefore, the oil is not agitated by the crankshaft 31 within the crank chamber 12, and of course, the oil is not agitated by the cam chain, clutch, etc. outside the crank chamber 12. Therefore, problems such as an increase in oil temperature and a decrease in engine output due to oil agitation, as described in the conventional example, do not occur. In addition, as mentioned above, when the engine is running, there is a level difference between the oil level in the crank chamber 12 and the oil level in the oil chamber 13, and the IT balance between the two is slightly disturbed (although the balance between the crank chamber 12 and the oil level is slightly disturbed). Since the chambers 3 and 3 are placed in front and behind each other based on the mounting body, the imbalance in weight has almost no effect on the compartments.The oil accumulated in the oil chamber 13 is supplied by the pump 18. are supplied to required locations within the crank chamber 12 and required locations within the cam chamber 20 via the passage 19,
Lubricates the inner peripheral surface of the cylinder, the large and small ends of the connecting rod, the camshaft, etc. Then, the oil after lubricating the required parts in the crank chamber 12 is directly deposited at the bottom of the crank chamber 12.
1! Then, due to the above-mentioned pump action of the crank chamber 12, the oil is returned to the oil chamber 13 through the communication hole 15. On the other hand, the oil that lubricates the necessary parts in the cam chamber 20 is returned through the oil return passage 2). It is returned directly into the oil chamber 13. In this way, all the oil after lubrication is transferred to the crank chamber 1.
Part of the oil chamber 13 is directly removed without being returned to the oil chamber 13.
Since the oil level in the crank chamber 12 is returned to the inside, the rise of the oil level in the crank chamber 12 can be suppressed, and the oil stirring phenomenon caused by the crankshaft 31 can be more reliably prevented from occurring. Furthermore, in the above-described operation, if the volume of the crank chamber 12 is small, the negative pressure within the crank chamber 12 may become too high, which may cause a decrease in output or a loss of sealing performance. However, if there are six pistons in the engine with the above configuration, piston 2
Since the balancing hole 22 is opened and closed by the vertical movement of the crank chamber 12, it is possible to prevent the crank chamber 12 from becoming more negative pressure than necessary while ensuring the pumping action of the crank chamber 12. 7 [Effects of the Invention] Even when the pressure is small, the output does not decrease and the sealing performance is not impaired. a crank chamber, which undergoes repeated positive and negative pressure fluctuations due to the a one-way valve that only allows oil to flow from the chamber to the oil chamber side; an oil pump that is provided in the oil chamber and supplies the oil in the oil chamber to the cam chamber and the crank chamber via an oil supply path; and the cylinder. The structure includes a balancing hole that is drilled in the lower part and is opened and closed as the piston moves up and down, allowing the inside of the crank chamber to communicate with the outside when opened, so that the following excellent effects can be achieved. (11 The oil chamber is separate from the crank chamber (independently), and there is no member such as a crankshaft or cam chain that stirs the oil in the oil chamber, and of course this is used to stir the oil.) (2) The oil chamber is located behind the crank chamber, so when the engine is running, the oil chamber Even if the oil level height differs between the engine and the crank chamber, this has little effect on the vehicle balance, and a good balance can be maintained. (3) An oil pump supplies oil to each part of the engine. (4) There is a balancing hole that opens and closes when the piston moves up and down, so there is no risk that the main oil supply will be cut off when the electric body is tilted, etc. It is possible to reduce the negative pressure in the crank chamber from becoming too high while ensuring the pumping action of the chamber.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing a conventional example of a lubrication device for a four-stroke engine, and FIGS. 2 and 3 are -w
FIG. 2 is a longitudinal sectional side view of the engine, and FIG. 3 is a longitudinal sectional front view thereof. 11...Cylinder, 12...Crank chamber, 13...Oil chamber, 15...Communication hole, 16...One direction Valve, 18...Oil pump, 19...Oil supply path, 2)...
... Oil return chamber, 22 ... Balancing hole, 23 ... Piston.

Claims (2)

[Claims] (1) A crank chamber which is defined in a sealed manner at the bottom of the cylinder and undergoes repeated positive and negative pressure fluctuations as the piston moves up and down, and which is provided independently at the rear of the crank chamber and communicates with the crank chamber. an oil chamber communicated through a hole; a one-way valve installed in the communication hole that allows oil to flow only from the crank chamber toward the oil chamber; and a one-way valve provided in the oil chamber to allow oil in the oil chamber to flow. The oil pump includes an oil pump that supplies oil to the cam chamber and the crank chamber through an oil supply path, and a balancing hole that is bored in the lower part of the cylinder and opens and closes as the piston moves up and down, communicating the crank chamber with the outside when opened. A 4-cycle engine lubricating device characterized by: (2) The lubrication device for a cycle engine according to claim 1, wherein the cam chamber is communicated with the oil chamber via an oil return passage.