JPH0625527B2 - Lubricator for 4-cycle engine - Google Patents

Abstract

PURPOSE:To prevent the exhaustion of oil and permit the certain lubrication by constituting an oil chamber from a transmission chamber arranged 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 29 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 a transmission chamber 13 through a communication hole 15. Therefore, in the stationary state, the oil surface B in the transmission chamber 13 is set above the initial oil surface A. Therefore, oil exhaustion in a pump 20 is hardly generated. While, in the stationary state, the oil surface C in the crank chamber 12 is set lower than a crankshaft 32. Therefore, oil is not stirred by the crankshaft 32. The oil in the transmission chamber 13 is supplied into the crank chamber 12 and a cam chamber 22 through an oil passage 21 by the pump 20.

Description

The present invention relates to a lubrication device for a four-cycle engine.

"Prior Art" In a conventionally known four-cycle engine, in order to lubricate the valve operating system and the cylinder sliding surface, the lower part of the crank chamber is projected downward to form an oil sump and an oil pump there. The oil pump is used to supply oil to the required locations within the engine. However, in the engine having such a structure, there is a problem that it is difficult to make the engine body compact, especially in the vertical direction, because the engine main body projects downward.

Therefore, as an example of a vertically-compressed 4-cycle engine, the US "Dirt Bike" 198
The issue shown in FIG. 1 is described in the September, 2013 issue. This engine has a crank chamber 2 with a vertical movement of a piston 1.
The oil in the crank chamber 2 is moved to the cam chain chamber 3 provided adjacent to the side portion of the crank chamber by utilizing the pressure fluctuation of 1. and the oil in the cam chain chamber 3 is scraped up by the cam chain 4. It is configured to lubricate the valve operating system and the cylinder sliding surface by moving it to a predetermined position.

"Problems to be solved by the invention" However, in the four-cycle engine having the above-mentioned configuration,
(a) Since the cam chain chamber 3 is an oil chamber, an oil agitation phenomenon occurs due to the cam chain 4, which causes an increase in oil temperature and a decrease in engine output. (b) In addition, the oil chamber is located on the side of the crank chamber (side with respect to the vehicle body), and when the engine is running and the oil surface height is different as shown in the figure, the weight balance is unfavorable. . (c) The oil in the cam chain chamber 3 is supplied to each required part of the engine by scraping up the chain 4, and the oil surface may be below the cam chain 4 when the vehicle body is tilted. In that case, there is an inconvenience that oil may run out and smooth lubrication may not be performed.

The present invention has been made in view of the above circumstances, and prevents an increase in temperature and a decrease in output of oil due to oil agitation while achieving a compact engine, and has a good weight balance even when the engine is driven, and when the vehicle body is tilted. It is an object of the present invention to provide a lubrication device for a 4-cycle engine that can surely supply oil to each required location in the engine.

[Means for Solving the Problems] In order to achieve the above-mentioned object, in the present invention, a crank chamber which is defined in a closed state in a lower portion of a cylinder and which repeats pressure fluctuations with vertical movement of a piston, and a rear portion of the crank chamber. And a transmission chamber defined in the lower part of the crank chamber and communicated with the crank chamber through a communication hole, and an oil flow allowed from the crank chamber to the mission chamber side through the communication hole. A one-way valve, and an oil pump which has an intake port arranged in the mission chamber and supplies oil in the mission chamber to a cam chamber and a crank chamber through a supply passage.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 2 to 4.

FIG. 2 is a vertical cross-sectional side view of an engine equipped with a lubricating device according to the present invention. In the figure, reference numeral 11 is a cylinder, and a crank chamber 12 is defined below the cylinder 11 in a closed state. That is, the crank chamber 12 can store oil in a liquid-tight state in its lower portion,
Although it is communicated with the outside through a minute gap between the piston ring and the cylinder 11, the oil supply passage 21, and the like, it is formed as a closed space in which a pressure fluctuation can be sufficiently generated as the piston 29 moves up and down. Also, the crank chamber 1
Mission room 1 behind 2 (rear with respect to vehicle body)
3 are defined. The mission chamber 13 is separated from the crank chamber 12 by a partition wall 14, and furthermore, the crank chamber 1 is connected via a communication hole 15 penetrating the lower portion of the partition wall 14.
It is connected to 2. Further, the communication hole 15 is provided with a one-way valve 16 that allows only the flow of oil from the crank chamber 12 to the transmission chamber 13. One way valve 16
Is a configuration in which the upper end of a plate-shaped valve body is screwed from the mission chamber 13 side so as to close the communication hole 15, and the function of a one-way valve is achieved by the elastic action of the valve body itself.

In the mission chamber 13, an oil pump 20 is arranged in addition to a main shaft 18 and a counter shaft 19 that support a gear group for shifting. The oil pump 20 has its suction port arranged below the oil surface in the mission chamber, and its discharge port is connected to the base end side of the oil supply passage 21, and the tip end side of the oil supply passage 21 is the crank chamber 1
2 extends to a required location in 2 and a required location in the cam chamber 22. Reference numeral 23 is a clutch chamber (see FIG. 3), and the clutch chamber 23 is connected to the cam chamber 22 via a cam chain chamber 24. Also clutch room 2
3 is separated from the mission chamber 13 by a partition wall 25, and is communicated with the mission chamber 13 through a communication hole 27 formed in an upper portion of the partition wall 25 facing the clutch 26 (FIG. 4). reference).

On the other hand, 28 is a balancing hole for communicating the clutch chamber 12 with the mission chamber 13. The hole 28 is provided so as to penetrate the side wall of the cylinder 11 and the partition wall 14, and is opened and closed by the vertical movement of the piston 29. It Moreover, the balancing hole 28 is provided in an inclined state so that the oil in the crank chamber 12 easily flows out to the mission chamber 13 side so that the mission chamber 13 side is downward. And the crank chamber 12 and the mission chamber 1
Balancing holes 2 are provided in the partition wall 14 for partitioning the partition walls 3 from each other.
A baffle plate 30 extending to the center of the inside of the mission chamber 13 is provided at a lower position of 8, so that the oil in the mission chamber 13 flows out to the crank chamber 12 through the balancing hole 28 even when the vehicle body is bound. There is no such thing. Reference numeral 31 in FIG. 3 denotes a seal member arranged between the outer periphery of the end portion of the crankshaft 32 and the casing, whereby the generator chamber 33 provided on the side of the crank chamber 12 is Is sealed against. Reference numeral 34 in FIG. 4 denotes a communication hole provided in the partition wall 25 for overflow.

Next, the operation of the lubricating device configured as described above will be described.

A required amount of oil has been previously injected into the engine body, and A in FIG. 2 indicates the oil surface when the engine is stopped. When the piston 29 moves up and down as the engine starts, positive and negative pressure fluctuations in the crank chamber 12 are repeated. Along with this, the one-way valve 16 is opened and closed, and the crank chamber 1
The oil in 2 and the breathing gas together with the communication hole 15
Is discharged into the mission chamber 13 via. As a result, the oil in the crank chamber 12 is gradually transferred to the mission chamber 13
Then, in the steady state, the oil surface in the mission chamber 13 is above the initial oil surface A as shown by B in FIG. Therefore, the oil pump 20 is unlikely to run out of oil, and the oil can be reliably supplied to each required part in the engine.

On the other hand, in the above-mentioned steady state, the oil level in the crank chamber 12 is set to the crankshaft 3 as shown by C in FIG.
It is below the second weight portion 32a. Therefore, the oil is not agitated by the crankshaft 32 in the crank chamber 12, and the oil is not agitated by the cam chain or the like outside the crank chamber 12. Therefore, it is possible to prevent the inconveniences such as the temperature rise of the oil and the output reduction of the engine due to the oil agitation as described in the conventional example. Since the rotating parts such as the transmission gear in the mission chamber 13 can be arranged above the oil surface B as shown in FIG. 2, even if the oil surface B becomes higher, the oil agitation by the transmission gear becomes higher. It is possible to reduce the temperature rise and output decrease of the oil.

In addition, as described above, when the engine is driven, a step is created between the oil surface of the crank chamber 12 and the oil surface of the mission chamber 13, and the weight balance is lost between the two. The fact that the weight balance is out of order has almost no influence on the vehicle because the vehicle is arranged in front of and behind the vehicle.

The oil accumulated in the mission chamber 13 is stored in the pump 2
0 through the oil supply passage 21 to the required locations in the crank chamber 12 and the cam chamber 22, respectively, to lubricate the cylinder inner peripheral surface, connecting rod large end / small end, cam shaft, etc. I do. Then, the oil after lubricating the required parts in the crank chamber 12 flows down to the bottom of the crank chamber 12 as it is, and is returned to the inside of the mission chamber 13 through the communication hole 15 by the pump action of the crank chamber 12 described above.

On the other hand, the oil that has been lubricated at the required places in the cam chamber 22 travels along the wall surface of the cam chain chamber 24 and reaches the clutch chamber 23,
The oil that has reached the clutch chamber 23 is scraped up by the clutch constituent members and directly returned to the mission chamber 13. As described above, since the oil after lubrication is not entirely returned to the clutch chamber 12 but a part thereof is directly returned to the mission chamber 13, it is possible to suppress an increase in the oil level of the clutch chamber 12, and thus the crankshaft 32. It is possible to more reliably prevent the oil agitation caused by.

Further, in the above operation, when the volume of the crank chamber 12 is small, the negative pressure of the crank chamber 12 becomes too high,
Although the output may be reduced or the sealing performance may be impaired, in the engine having the above configuration, the balancing hole 28 that is opened and closed by the vertical movement of the piston 29 is provided, so that the pump action of the crank chamber 12 is ensured. It is possible to prevent the crank chamber 12 from having a negative pressure more than necessary. Therefore, even when the volume of the crank chamber 12 is small, the output is not reduced and the sealing performance is not impaired.

Although the piston 29 is used to open and close the balancing hole 28 in the above embodiment, a rotary valve that operates in synchronization with the movement of the piston 29 is provided,
It may be configured to open and close by this.

Further, although the oil pump 20 is provided in the mission chamber, it is not always necessary that the main body of the oil pump 20 is provided in the mission chamber, and its suction port is located at a position where oil in the mission chamber can be sucked. As long as it is arranged, it may be arranged outside the mission chamber, for example.

[Advantages of the Invention] As described above, according to the first invention of the present application, (a) since the oil in the crank chamber is discharged to the mission chamber, the oil level in the crank chamber can be kept low, and By preventing oil agitation by the shaft, it is possible to prevent oil temperature rise and output decrease. (b)
Since the oil chamber is composed of the mission chamber located behind the crank chamber, even if the oil surface height is different between the oil chamber and the crank chamber when the engine is driven, it gives the vehicle balance. Little impact,
Good weight balance can be maintained. Further, there is no need to provide an oil chamber specially, and cost reduction and compactness can be achieved. (c) Since oil is supplied to the required parts of the engine by the pump, there is no risk of oil running out even when the vehicle body is tilted, and reliable lubrication can be achieved.

According to the second invention of the present application, in addition to the effects of the first invention,
Since the clutch chamber communicates with the cam chamber and the mission chamber and is used as an oil return passage, the clutch can be lubricated and the oil after the cam chamber lubrication can be directly returned to the mission chamber. By lowering the surface, it is possible to more reliably prevent the oil agitation phenomenon due to the crankshaft from occurring.

According to the third invention of the present application, in addition to the effects of the first invention,
Since the generator chamber is kept sealed by the seal member with respect to the crank chamber, the lubricating oil does not reach the generator chamber, and it is possible to prevent oil agitation by the generator rotor. Since there is no heat conduction from the oil to the oil, it is possible to suppress the temperature rise of the oil.

According to the fourth invention of the present application, in addition to the effects of the first invention,
Since a balancing hole that is opened and closed by the vertical movement of the piston is provided, while ensuring the pumping action of the crank chamber,
It is possible to prevent the negative pressure in the crank chamber from becoming too high, and it is possible to prevent the output from decreasing and the sealing performance from being impaired.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing a conventional example of a lubrication device for a four-cycle engine, FIGS. 2 to 4 show one embodiment of the present invention, and FIG. 2 is a longitudinal side view of the engine. FIG. 3 is a vertical sectional front view of the engine, and FIG. 4 is a view of a side wall interposed between the clutch chamber and the mission chamber as viewed from the mission chamber side. 11 ... Cylinder, 12 ... Crank chamber, 13 ... Mission chamber, 14, 25 ... Partition wall, 15, 27 ... Communication hole, 16 ... One-way valve, 20 ... Oil pump, 21 ...
... oil supply path, 22 ... cam chamber, 23 ... clutch chamber, 2
4 ... Cam chain chamber, 26 ... Clutch, 28 ... Balancing hole, 29 ... Piston, 31 ... Seal member, 32 ... Crankshaft, 33 ... Generator chamber.

Claims (4)

[Claims] 1. A crank chamber defined in a lower portion of a cylinder in a closed state, in which pressure fluctuations are repeated as the piston moves up and down,
A transmission chamber defined in the rear of the crank chamber and communicating with the crank chamber through a communication hole provided in the lower portion of the crank chamber, and oil from the crank chamber to the transmission chamber side, which is interposed in the communication hole. A one-way valve that allows only the flow of the oil, and an oil pump that has an intake port disposed below the oil surface of the mission chamber and that supplies oil in the mission chamber to a cam chamber and a crank chamber via a supply path. Lubricator for 4-cycle engine. 2. A crank chamber which is defined in a closed state in a lower portion of a cylinder, and which repeats pressure fluctuations as the piston moves up and down,
A transmission chamber defined in the rear of the crank chamber and communicating with the crank chamber through a communication hole provided in the lower portion of the crank chamber, and oil from the crank chamber to the transmission chamber side, which is interposed in the communication hole. A one-way valve that allows only the flow of oil, an oil pump that has an intake port disposed below the oil surface of the mission chamber and that supplies oil in the mission chamber to a cam chamber and a crank chamber through a supply path, and the cam chamber. And a clutch chamber which is provided in the lower portion of the clutch in communication with the cam chamber and communicates with the transmission chamber through a communication passage opening to the side of the clutch. 3. A crank chamber defined in a closed state in the lower part of the cylinder, and which repeats pressure fluctuations as the piston moves up and down,
A transmission chamber defined in the rear of the crank chamber and communicating with the crank chamber through a communication hole provided in the lower portion of the crank chamber, and oil from the crank chamber to the transmission chamber side, which is interposed in the communication hole. Of the crank chamber, a one-way valve that allows only the flow of the oil, a suction port that is disposed below the oil surface of the mission chamber and that supplies oil in the mission chamber to the cam chamber and the crank chamber through the supply passage, A lubrication device for a four-cycle engine, comprising: a seal member attached to an outer periphery of an end portion and provided on a side portion of the crank chamber to keep a generator chamber in a sealed state with respect to the crank chamber. 4. A crank chamber, which is defined in a closed state in a lower portion of a cylinder, and which repeats pressure fluctuations as the piston moves up and down,
A transmission chamber defined in the rear of the crank chamber and communicating with the crank chamber through a communication hole provided in the lower portion of the crank chamber, and oil from the crank chamber to the transmission chamber side, which is interposed in the communication hole. A one-way valve that allows only the flow of the oil, an oil pump that has an intake port disposed below the oil surface of the mission chamber and that supplies oil in the mission chamber to a cam chamber and a crank chamber through a supply path, and a cylinder of the cylinder. A lubrication device for a four-cycle engine, which is provided with a balancing hole that is provided in a lower portion and that is opened / closed in accordance with a vertical movement of a piston and that allows the crank chamber to communicate with the mission chamber when opened.