JP2760693B2 - Oil storage structure of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a crankcase having a crankshaft chamber and a transmission chamber, and a partition for separating the transmission chamber and the crankshaft chamber is formed integrally with the crankcase. The present invention relates to an oil storage structure of an internal combustion engine provided with an oil pump mechanism that constantly pumps oil.

[0002]

2. Description of the Related Art In order to keep the overall height of an engine low and to reduce the size and weight of the engine, an oil is provided which has a partition for separating a transmission chamber and a crankshaft chamber, and which sets the oil level in the transmission chamber higher than other parts. A storage structure is provided in JP-A-61-215411.

[0003]

However, if the oil level in the transmission chamber is set high, various transmission gears constituting the transmission mechanism are constantly immersed in oil, so that the oil is stirred by the gears, and As the friction increases, the air pump is more likely to be caught in the air. Also, at the time of sudden braking or steep downhill,
A large amount of oil in the transmission chamber flows into the crankshaft chamber over the partition wall, increasing the friction of the crankshaft, leading to a decrease in the number of revolutions.

[0004]

SUMMARY OF THE INVENTION Crankshaft chamber 10
And a crankcase having a transmission chamber 11 and
In an internal combustion engine provided with an oil pump mechanism 50 that integrally forms a partition wall 40 for separating the transmission chamber 11 and the crankshaft chamber 10 from the crankcase and that constantly pumps oil from the crankshaft chamber 10 to the transmission chamber 11, The clutch cover 2 is attached to one end in the axial direction of the case to form a clutch chamber 12, and the other end in the axial direction forms a magneto chamber 13. The magneto chamber 13 communicates with the crankshaft chamber 10 and
And the transmission chamber 11 and the clutch chamber 12 store oil at a higher level than the crankshaft chamber 10 and communicate the transmission chamber 11 and the clutch chamber 12 so that the oil levels are substantially the same. doing.

[0005]

[Operation] The transmission chamber and the clutch chamber are communicated with each other, and the oil is stored at substantially the same level in both chambers, so that the oil storage volume is increased, and the oil level is lowered while the total oil amount is sufficiently maintained. be able to. As a result, the transmission gear constituting the transmission mechanism is not immersed in the oil, so that the friction on the gear can be reduced and the oil pump can be prevented from being caught in the air. Also, since the oil level can be lowered, the partition wall separating the transmission chamber and the crankshaft chamber is relatively high with respect to the oil level. Oil can be prevented from overflowing.

[0006]

FIG. 1 is a right side view of an internal combustion engine to which the present invention is applied. A crankcase 2 is fixed to a lower side of a cylinder block 1 and a clutch cover 7 is fixed to a right side of the crankcase 2. Have been. O1 is a crankshaft center, and O2 is a transmission shaft center. In FIG. 2 showing a left side view, a magneto cover 8 is fixed to the left side of the crankcase 2.

In FIG. 3, which shows a cross-sectional view taken along the line III-III of FIG. 1, the crankcase 2 has a left-right split structure.
The right case member 3 and the left case member 4 are joined at a center mating surface. The first half of the crankcase 2 is a crankshaft chamber 10 for housing a crankshaft 16, and the second half is a transmission chamber 11 for housing a transmission mechanism.

In the transmission chamber 11, various gears are provided on a transmission shaft 26, an output shaft 27, and both shafts 26 and 27 as a transmission mechanism, and a kick starter shaft 28 and the like are arranged. The output shaft 27 has an output sprocket 3
0 is fixed.

A clutch chamber 12 surrounded by a side wall of the right case member 3 and the clutch cover 7 is formed at a rear portion on the right side of the crankcase 2, and accommodates a multi-plate friction clutch 33. The multi-plate friction clutch 33 is provided at an end of the transmission shaft 26 extending from the transmission chamber 11.

In the left front portion of the crankcase 2, a magneto chamber 13 is formed which is surrounded by a side wall of the left case member 4 and a magneto cover 8, and a flywheel magneto 35 is accommodated therein. The flywheel magneto 35 is connected to the crankshaft 16 extending from the crankshaft chamber 10.
It is attached to.

FIG. 5 is a side view of the inner side (joining surface side) of the right case member 3. Between the crankshaft chamber 10 at the front and the transmission chamber 11 at the rear, both extend upward from the lower part and extend upward. The right half of the weir-shaped partition wall 40 separating the chambers 10 and 11 is integrally formed. Further, an eave-shaped rib 43 extending from the rear wall of the mission chamber to the partition wall 40 is formed below the mission chamber 11. The lower end of the partition wall 40 is connected to a bottom partition wall 41. The bottom partition wall 41 extends forward under the crankshaft chamber 10 to reach the front end wall of the crankshaft chamber, and has an oil pan between the crankshaft chamber bottom wall and the oil pan. 37 are formed. The oil pan 37 communicates with the transmission chamber 11 at the rear.

FIG. 7 is a side view of the inner side (joining surface side) of the left case member 4. The left half of the weir-like partition 40 and the left half of the bottom partition 41 correspond to the structure of the right case member 3. Half is formed integrally. Further, an eave-shaped rib 43 is formed in the lower part of the transmission chamber 11 similarly to the right case member 3, but at the time of assembly, the left and right ribs 43 are formed.
A gap is ensured between them, and oil flows between the left and right ribs 43.

In FIG. 4 showing an outer side view of the right case member 3, a communication hole 45 is formed at a position corresponding to the lower end portion of the clutch chamber 12, and the communication hole 45 is provided with an oil as shown in FIG. The clutch chamber 12 (FIG. 4) communicates with the transmission chamber 11 through the oil pan 37 so that the oil level L1 between the transmission chamber 11 and the clutch chamber 12 is maintained at substantially the same level. I have to. The oil level L1 is high enough that each gear of the transmission mechanism is not immersed in oil.

In FIG. 6, which shows a side view of the left case member 4, a communication hole 46 is also formed at a position corresponding to the bottom of the magneto chamber 13, and the communication hole 46 is formed as shown in FIG. The oil level L2 in the crankshaft chamber 0 and the oil level L2 in the magneto chamber 13 are maintained at substantially the same height. The oil level L2 is the oil level L of the transmission chamber 11.
It is set to be lower than 1 and low enough that the crankshaft 16 is not immersed in oil, that is, nearly zero.

Next, a pumping oil pump mechanism for constantly pumping oil into the transmission chamber 11 and a lubricating oil pump mechanism for supplying oil to each lubricating point will be described. 10, a pumping oil pump mechanism 50 and a lubricating oil pump mechanism 51 are arranged on the same axis below the crankshaft 16 in FIG. Both are trochoid pumps.

The pump casing 53 and the pump cover 54 of the lubricating oil pump mechanism 51 are
Of the pump casing 5
A pump shaft 56 that penetrates the pump shaft 3 and the pump cover 54 is supported, and an inner rotor 57 is fixed to a portion of the pump shaft 56 inside the casing. The pump shaft 5
6 extends into the clutch chamber 12 on the right side, and the input gear 60
Is fixed, and the input gear 60 is connected to the crankshaft 1.
6 meshes with the pump drive gear 20.

A casing 61 of the pumping oil pump mechanism 50 is formed integrally with the clutch cover 7, a pump cover 62 is fixed to a left end surface of the casing 61, and an inner rotor 65 is disposed in the casing 61. . The pump shaft 66 to which the inner rotor 65 is fixed is
It is arranged on the same axis as the pump shaft 56 for lubricating oil, the right end is supported by the bag-shaped bearing recess 70 of the casing 61, and the left end extends leftward through the pump cover 62. And is connected to the lubricating oil pump pump shaft 56 by an Oldham type coupling mechanism 71.
That is, from the crankshaft 16 to the pump drive gear 2
The rotational force input to the input gear 60 via the zero is transmitted to both pump shafts 56 and 66, and simultaneously drives both pump mechanisms 50 and 51. The joint mechanism 71 is formed by meshing a linear projection formed on an end face of one pump shaft 66 with a linear groove formed on the other pump shaft 56.

The oil passage structure of the pumping oil pump mechanism 50 will be described. In FIG. 5, the crankshaft chamber 10 is provided at the lowermost end of the crankshaft chamber 10, that is, on the side wall of the right case member 3 at the lower end of the partition wall 40.
A suction port 71 for sucking oil is formed. The suction port 71 penetrates the right case member 3 as shown in FIG. 4 and communicates with an oil suction passage 72 formed in the clutch cover 7 in FIG. And pumping oil pump mechanism 50
Is connected to the suction port 77. The discharge port 78 of the pumping oil pump mechanism 50 communicates with a discharge passage 75 in the clutch cover 7, and the lower end 75a of the discharge passage 75 is opened at the mating surface. It communicates with the opening 80 of the case member 3. The opening 80 is
As shown in FIG. 5, it opens into the mission chamber 11.

The oil passage structure of the lubricating oil pump mechanism 51 will be described. In FIG. 5, near the lower end of the right case member 3, an oil suction port 82 that opens toward the transmission chamber 11 is opened. The oil suction port 82 is connected to the suction passage 83 through the suction chamber 82a in FIG. The suction passage 83 communicates with the suction port 51 a of the lubricating oil pump mechanism 51. Lubrication oil pump mechanism 5
One discharge port 51 b communicates with the discharge passage 84. The suction chamber 82a, the suction passage 83, and the discharge passage 84
As shown in FIG. 8, a part is also formed on the inner surface side of the clutch cover 7. The front end of the discharge passage 84 communicates with an upward passage 86 formed in the clutch bar 7, and the upper end of the upward passage 86 communicates with the upstream side in the filter case 22. The downstream side of the filter case portion 22 communicates with an oil hole 94 of the crankshaft 16 and a crankpin portion via an oil passage 90, an oil chamber 91, and the like in the clutch cover 7 as shown in FIG.
Although not shown, it communicates with each lubrication point in the crankcase. The lubricated oil returns to the crankcase 2.

Next, the operation will be described. In the transmission chamber 11 and the clutch chamber 12, oil is stored at substantially the same level L1, and the level L1 is high enough that the transmission gear in the transmission chamber is not immersed. On the other hand, oil is stored in the crankshaft chamber 10 and the magneto chamber 13 at substantially the same level L2 at least so that the lower end of the crankshaft 16 is not immersed. actually,
The level L2 is almost as high as zero.

During operation of the engine, both pump shafts 5 are driven through the pump drive gear 20 and the input gear 60 of the crankshaft 16.
By transmitting the power to the oil pumps 6, 66, both oil pump mechanisms 50, 51 are constantly rotating. In each drawing, the flow of oil by the pumping oil pump mechanism is indicated by a thick solid line arrow, and the flow of oil by the lubricating oil pump mechanism is indicated by a broken arrow.

In FIG. 6, the oil remaining at the bottom of the magnet chamber 13 enters the crankshaft chamber 10 through the communication hole 46 as shown in FIG. 7, and the oil remaining at the bottom of the crankshaft chamber 10 is as shown in FIG. The oil is sucked from the lower end oil suction port 71, enters the pumping oil pump mechanism 50 through the suction passage 72 in FIG. 8, and is pressurized. Then, it is supplied to the discharge passage 75 from the discharge port 78 and is discharged through the opening 80 in FIG.

On the other hand, the oil taken in for lubrication from the suction port 82 in FIG. 5 enters the lubrication oil pump mechanism 51 through the suction passage 83 in FIG. 4 and is pressurized there.
After being purified by the oil filter 23 through the discharge passage 84 and the upward oil passage 86 in FIG. 8, the oil is sent to each lubricating point in the crankcase, and returned to the crankcase 2 after lubrication.

[0024]

As described above, according to the present invention, the transmission chamber 11 and the crankshaft chamber 10 in the crankcase 2 are separated from each other by the partition wall 40, and the transmission chamber 11 and the clutch chamber 12 are separated from the crankshaft chamber 10. Since the oil is stored at a high level and the transmission chamber 11 and the clutch chamber 12 communicate with each other so that the oil level is substantially the same, the oil storage volume is enlarged, and the oil level is maintained while the total oil amount is sufficiently maintained. Can be reduced. As a result, the transmission gear that constitutes the transmission mechanism is not immersed in the oil, the friction on the gear can be reduced and the air pump can be prevented from being caught by the oil. Such friction can be reduced, and the energy efficiency of the engine can be improved.

Further, since the oil level can be lowered, the partition wall 40 separating the transmission chamber 11 and the crankshaft chamber 10 becomes relatively high with respect to the oil level. Mission room 1
1 can prevent oil from overflowing into the crankshaft chamber 10. Since the oil storage volume is increased into the clutch chamber 12 to lower the oil level, the depth of the lower oil pan can be reduced, and compactness can be achieved. Further, a magneto chamber 13 is formed on the side of the crankshaft chamber 10 opposite to the side where the clutch chamber is disposed in the axial direction,
Since the magneto chamber 13 communicates with the crankshaft chamber 10 and has approximately the same oil level as the crankshaft chamber 10, a sufficient oil storage area is ensured while keeping the oil level in the crankshaft chamber 10 low, and the pump mechanism The oil supply to the mission chamber 11 by the fuel cell 50 can be stabilized. In other words, the present invention basically transmits oil from the crankshaft chamber 10 to the transmission chamber 11 and the clutch chamber 12 communicating with the transmission chamber 11 so that the transmission chamber 11 and the clutch chamber 12
The oil level of the oil pump mechanism 5 is set to a predetermined height.
0, the oil is constantly pumped and the level is lower than that of the transmission chamber 11 or the like. Room 10
It is conceivable that the amount of oil in the chamber fluctuates. in this case,
When the amount of oil in the crankshaft chamber 10 decreases extremely, the oil pump
Although the oil cannot be sent to the fuel cell 1 or the like, as in the present invention, the crankshaft chamber 10 is communicated with the magneto chamber 13 to substantially increase the oil storage volume.
The oil supply to the mission chamber 11 can be stabilized.

[Brief description of the drawings]

FIG. 1 is a right side view of an internal combustion engine to which the present invention is applied.

FIG. 2 is a left side view of the internal combustion engine to which the present invention is applied.

FIG. 3 is a sectional view taken along the line III-III of FIG. 1;

FIG. 4 is a right side view (external side view) of a right side case member of the crankcase.

FIG. 5 is a left side view (an inner side view) of a right case member of the crankcase.

FIG. 6 is a left side view (an external side view) of a left case member of the crankcase.

FIG. 7 is a right side view (an inner side view) of a left case member of the crankcase.

FIG. 8 is a left side view (an inner side view) of the clutch cover.

FIG. 9 is a right side view (an inner side view) of the magneto cover.

FIG. 10 is an enlarged cross-sectional view taken along line XX of FIG. 1;

[Explanation of symbols]

 2 Crankcase 3 Right case member 4 Left case member 10 Crankshaft chamber 11 Transmission chamber 12 Clutch chamber 40 Partition wall 50 Pumping oil pump mechanism

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 57/04 F01M 1/02 F01M 11/00

Claims (1)

(57) [Claims] A crankcase having a crankshaft chamber and a transmission chamber is provided in the crankcase.
In an internal combustion engine provided with an oil pump mechanism 50 for continuously pumping oil from the crankshaft chamber 10 to the transmission chamber 11, the clutch cover 2 is attached to one end in the axial direction of the crankcase. A chamber 12 is formed, and a magneto chamber 13 is formed at the other end in the axial direction. The magneto chamber 13 communicates with the crankshaft chamber 10 and has substantially the same oil level as the crankshaft chamber 10. An oil storage structure for an internal combustion engine, wherein oil is stored at a higher level than the crankshaft chamber 10 and the transmission chamber 11 and the clutch chamber 12 communicate with each other so that the oil level is substantially the same.