JP4007875B2 - Lubricating device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oil chamber structure of a semi-dry sump crankcase of a small internal combustion engine.
[0002]
[Prior art]
Conventionally, such an oil chamber structure in a crankcase has been disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-282826. This is because the lubricating oil that has lubricated the piston, crankshaft, etc. is dropped from the bottom of the crank chamber to the oil reservoir below it, and a one-way valve is provided here to discharge to the oil chamber and prevent backflow to the crank chamber To do. In this case, the oil strainer serving as the inlet of the lubricating oil pipe to the oil pump is disposed in the oil chamber immediately downstream of the one-way valve.
[0003]
[Problems to be solved]
In the conventional lubrication apparatus, since the blowout part of the one-way valve and the oil strainer are close to each other, air or the like is easily mixed into the lubricating oil sucked up by the oil pump. Moreover, since the oil chamber cannot be made large, the oil level for securing the required amount of oil has become high.
[0004]
[Means for solving the problems and effects]
In order to solve the above-described conventional problems, the present invention provides an internal combustion engine in which a crankcase is constituted by a pair of engine cases, and a crank chamber and a mission chamber are formed in the engine cases coupled to each other. An oil reservoir provided below the crank chamber in one of the engine cases and communicating with the crank chamber; a first oil chamber provided in the other of the pair of engine cases; the oil reservoir; A one-valve connecting the first oil chamber and allowing only the flow of lubricating oil from the oil reservoir side to the first oil chamber side, and provided in the one of the pair of engine cases; a second oil chamber having a built-in oil strainer as the inlet of the lubricating oil conduit toward the pump, is disposed below the crank chamber, the first and second o Proposes a lubrication system for an internal combustion engine, characterized in that an oil passage communicating with each other le chamber.
[0005]
As described above, in the present invention, the lubricating oil discharged from the one valve first enters the first oil chamber provided in one of the pair of engine cases, and then provided in the other of the pair of engine cases. To the second oil chamber through an oil passage communicating them, where it is sucked up from the oil strainer. Thus, since the path of the lubricating oil from the one-way valve to the oil strainer is long, the air mixed in the lubricating oil during that time is completely separated and stable oil suction is performed.
[0006]
In the present invention, since the oil storage space having a large area and capacity can be secured including the first and second oil chambers and the oil passages communicating with the first and second oil chambers, the oil level in the oil chamber can be lowered.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a longitudinal rear view of an internal combustion engine according to an embodiment of the present invention cut along a plane (II chain line in FIG. 3) including a cylinder axis and a crankshaft axis, and FIG. It is a vertical rear view cut | disconnected and shown by the plane (II-II chain line | wire of FIG. 3) also including FIG. FIG. 3 is a right side view showing a state in which the right crankcase cover of FIG. 2 is removed, and a cross section including the cylinder axis is also drawn (viewed along arrow III-III in FIG. 2). FIG. 4 is a left side view (a view taken along arrows IV-IV in FIG. 2) showing a state in which the left crankcase cover in FIG. 2 is removed. Further, FIG. 5 is a cross-sectional view taken along the line VV in FIG.
[0008]
In these drawings, the cylinder block 1 of the internal combustion engine E is provided with a cylinder bore 3 for slidably fitting the piston 2, and between the cylinder head 4 coupled to the cylinder block 1 and the top of the piston 2. The combustion chamber 5 is formed. An intake valve 7 for switching communication / blocking between the intake port 6 and the combustion chamber 5 and an exhaust valve 9 for switching communication / blocking between the exhaust port 8 and the combustion chamber 5 are cylinders that can be opened and closed freely. It is supported by the head 4. Then, the cam 11 that rotates integrally with the cam shaft 10 is opened and closed via the rocker arm 12.
[0009]
The crankcase 30 coupled to the lower side of the cylinder block 1 is composed of a pair of left and right engine cases 32 and 33, and a crank chamber 34 is formed in the crankcase 30. The transmission mission case 31 is also constituted by the engine cases 32 and 33. The left and right engine cases 32 and 33 are separated from each other by a partition wall 36 that separates the crank chamber 34 and the transmission chamber 35 from each other. (See FIG. 5). In addition, as viewed in the axial direction of the crankshaft 14, as shown in FIGS. 1 and 2, the crank webs 14a, 14a are sandwiched between the left and right engine cases 32, 33, and the shaft portions are oil seals 37, 38. It is sealed by. That is, the crank chamber 34 is a sealed type. Crankcase covers 39 and 40 are attached to the outer sides of the left and right engine cases 32 and 33, respectively.
[0010]
The crankshaft 14 is housed in the crank chamber 34, and both ends are rotatably supported by the left and right engine cases 32, 33. The crankshaft 14 includes a pair of crank webs 14a, 14a and a crank pin 14b for connecting the crank webs 14a, 14a. A connecting rod 13 connected to the piston 2 is rotatably connected to the crank pin 14b. Installed.
[0011]
When the piston 2 is pushed down by the combustion of the fuel in the combustion chamber 5, the reciprocating motion becomes the rotational motion of the crankshaft 14 via the connecting rod 13. The rotation of the crankshaft 14 is transmitted to the main shaft 15 and the counter shaft 16. The rotation of the crankshaft 14 is also transmitted to the camshaft 10 via the sprocket 19 and the chain 20 shown in FIGS. In FIG. 3, 18 is a water pump shaft. Moreover, 21 in FIG. 1, FIG. 2 shows a generator.
[0012]
In the present embodiment, in the left engine case 32, the lower part of the wall surrounding the crank chamber 34 is partially interrupted, and an oil sump 41 formed below the cut 34a communicates with the crank chamber 34 (FIG. 2, (See FIG. 5). A one-valve 42 is provided between the oil sump 41 and a first oil chamber 43 formed in the right engine case 33 on the right side, and the first oil sump 41 communicating with the crank chamber 34 side has a first valve 42. Only the flow of the lubricating oil toward the oil chamber 43 side is allowed.
[0013]
The first oil chamber 43 formed in the space below the crank chamber 34 in the right engine case 33 further extends into the right crankcase cover 40.
[0014]
On the other hand, the space below the crank chamber 34 in the left engine case 32 extends into the left crank case cover 39 to form a second oil chamber 44. In the second oil chamber 44, an oil strainer 47 serving as an inlet of the lubricating oil conduit 46 directed to the oil pump 45 (see FIG. 4) is provided.
[0015]
As shown in FIG. 1, the first oil chamber 43 and the second oil chamber 44 communicate with each other through an oil passage 48.
[0016]
The lubricating oil that has lubricated the piston 2, the crankshaft 14, etc. falls from the bottom of the crank chamber 34 to the oil reservoir 41 through the cut 34 a.
[0017]
The pressure in the crank chamber 34 and the oil sump 41 communicating therewith fluctuates due to the reciprocating motion of the piston 2. When the pressure on the right side of the one valve 42 becomes higher, the one valve 42 is pushed open, and the lubricating oil in the oil reservoir 41 on the crank chamber 34 side becomes the first oil chamber 43 in the right engine case 33. Flow into. The lubricating oil in the first oil chamber 43 further flows to the second oil chamber 44 through the oil passage 48. Thereafter, the lubricating oil is sucked up by the oil pump 45 through the oil strainer 47 and the lubricating oil pipe 46 and supplied to various parts of the internal combustion engine E.
[0018]
As described above, in this embodiment, the lubricating oil blown from the one-way valve 42 first enters the first oil chamber 43 in the right engine case 33 and the right crankcase cover 40, and then passes through the oil passage 48 to the left engine case 32. , Flows into the second oil chamber 44 in the left crankcase cover 39, where it is sucked up from the oil strainer 47. As described above, since the path of the lubricating oil from the one-way valve 42 to the oil strainer 47 is long, the air mixed in the lubricating oil during that time is completely separated and stable oil suction is performed.
[0019]
In the present embodiment, a wide oil chamber 43, 44 is secured from the lower side of the crank chamber 34 to the inside of the left and right crankcase covers 39, 40, and a large-capacity oil passage 48 that communicates them is provided. Since all can be used as an oil pan, the oil levels of the first and second oil chambers 43 and 44 can be lowered as shown by the two-dot chain lines in FIGS. 3, 4, and 5. Further, since the rotor of the generator 21 is surrounded by the semicircular plate 23 shown in FIGS. 1, 2 and 4, the friction caused by the large-diameter rotor can be reduced in combination with the low oil level. .
[Brief description of the drawings]
FIG. 1 is a longitudinal rear view of an internal combustion engine according to an embodiment of the present invention, cut along a plane (a chain line II in FIG. 3) including a cylinder axis and a crankshaft axis.
FIG. 2 is a longitudinal rear view taken along a plane (II-II chain line in FIG. 3) that also includes a one-way valve.
3 is a right side view showing a state in which the right crankcase cover of FIG. 2 is removed, and a cross section including a cylinder axis is also drawn (viewed along arrow III-III in FIG. 2).
4 is a left side view (a view taken along arrows IV-IV in FIG. 2) showing a state in which the left crankcase cover of FIG. 2 is removed.
5 is a cross-sectional view taken along the line V-V in FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Cylinder block, 2 ... Piston, 3 ... Cylinder bore, 4 ... Cylinder head, 5 ... Combustion chamber, 6 ... Intake port, 7 ... Intake valve, 8 ... Exhaust port, 9 ... Exhaust valve, 10 ... Cam shaft, 11 ... Cam, 12 ... Rocker arm, 13 ... Connecting rod, 14 ... Crank shaft, 14a ... Crank web, 14b ... Crank pin, 15 ... Main shaft, 16 ... Counter shaft, 18 ... Water pump shaft, 19 ... Sprocket, 20 ... Chain, 21 ... Generator, 23 ... Semicircle plate, 30 ... Crankcase, 31 ... Mission case, 32 ... Left engine case, 33 ... Right engine case, 34 ... Crank chamber, 34a ... Cut, 35 ... Mission chamber, 36 ... Bulk, 37, 38 ... Oil seal, 39 ... Left crankcase cover, 40 ... Right crankcase cover, 41 ... Oil reservoir, 42 ... One-way valve, 43 ... First oil chamber, 44 ... Second oil chamber, 45 ... Oil Pump, 46 ... Lubricating oil pipe Road, 47 ... Oil strainer, 48 ... Oil path.

Claims (3)

In the internal combustion engine in which the crankcase is constituted by a pair of engine cases, and a crank chamber and a mission chamber are formed in the engine cases coupled to each other.
An oil sump provided below the crank chamber in one of the pair of engine cases and communicating with the crank chamber;
A first oil chamber provided in the other of the pair of engine cases;
A one-way valve that connects the oil reservoir and the first oil chamber and allows only a flow of lubricating oil from the oil reservoir side toward the first oil chamber side;
A second oil chamber that is provided in the one of the pair of engine cases and incorporates an oil strainer that serves as an inlet of a lubricating oil conduit toward the oil pump;
An internal combustion engine lubrication device comprising: an oil passage disposed below the crank chamber and communicating with the first and second oil chambers.   A generator including a rotor that rotates integrally with being supported by a crankshaft is provided on one side of the engine case,
  2. The second oil chamber is formed between a cover that covers the generator and is attached to one side of the engine case and the engine case, and below the rotor. Lubricating device for internal combustion engine.   The oil passage is disposed adjacent to the oil reservoir;
  The lubricating device for an internal combustion engine according to claim 1 or 2, wherein a lower end of the first oil chamber is arranged at a position higher than a lower end of the second oil chamber.

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