JPH04298618A - Oil tank structure of dry sump lubricated internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides a dry sump system equipped with a scavenge pump that returns oil accumulated in an oil reservoir at the bottom of a crankcase to an oil tank, and a feed pump that supplies oil in the oil tank to each lubricating section. This article relates to an oil tank structure for a lubricated internal combustion engine.

0002

BACKGROUND OF THE INVENTION Conventionally, such a dry sump lubricated internal combustion engine is known, as described in Japanese Utility Model Application Laid-open No. 126508/1983, in which an oil tank is provided separately outside the internal combustion engine.

0003

[Problems to be Solved by the Invention] However, when the oil tank is provided externally as in the conventional dry sump lubricated internal combustion engine described above, the piping connecting the scavenge pump and feed pump provided on the internal combustion engine side to the oil tank becomes difficult. This not only increases production costs and weight, but also imposes various restrictions on the layout of the oil tank.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an oil tank structure for a dry sump lubricated internal combustion engine that is simple in structure, does not require piping, and is compact.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a scavenge pump that returns oil accumulated in an oil reservoir at the bottom of a crankcase to an oil tank;
In the oil tank structure of the dry sump lubricated internal combustion engine, which includes a feed pump that supplies oil in the oil tank to each lubricating section, the main shaft of a transmission connected to the crankshaft supported by the crankcase is connected to the crankshaft. A first feature is that the oil tank is disposed above the main shaft, a clutch is provided at one end of the main shaft, and the oil tank is formed in a space below the clutch inside the crankcase.

[0006] In addition to the above-mentioned first feature, the present invention also has the following features:
A second feature is that the primary ratio between the crankshaft and the main shaft is 1.

[0007] In addition to the above-mentioned first feature, the present invention also has the following features:
A third feature is that an oil passage leading from the scavenge pump to the oil tank is formed on a mating surface of the crankcase and the crankcase cover.

[0008]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is an overall side view of an internal combustion engine equipped with the lubricating device, FIG. 2 is an enlarged view of the main parts of FIG. 3 is an enlarged view of the main part of FIG. 1, FIG. 4 is a sectional view taken along line 4-4 in FIG. 1, and FIG. 5 is a 5--
5 is a sectional view taken along line 5, and FIG. 6 is a sectional view taken along line 6-6 in FIG.

A single-cylinder four-stroke internal combustion engine E for a motorcycle is equipped with a crankcase 3 divided into a right crankcase half 1 and a left crankcase half 2, and the front upper surface of the crankcase 3 has a cylinder. Block 4, cylinder head 5, and head cover 6 are joined. A crankshaft 8 is supported via a ball bearing 7 between the side wall 11 of the right crankcase half 1 and the side wall 21 of the left crankcase half 2, and a balancer is supported in front of the crankshaft 8 via a ball bearing 9. A shaft 10 is supported. Further, above and behind the crankshaft 8, a main shaft 11 and a counter shaft 12 of the mission M are supported via ball bearings 13 and 14, respectively, and below the main shaft 11, a shift fork shaft 15 and a shift drum are supported. 16 is supported.

As is clear from FIG. 5, the output gear 17 provided on the crankshaft 8 meshes with a balancer gear 18 which is keyed to the right end of the balancer shaft 10, and thereby the front primary balancer fixed to the left end of the balancer shaft 10. 19 is driven to rotate at the same speed as the crankshaft 8. On the other hand, the balancer drive gear 20 provided on the crankshaft 8 meshes with a balancer gear 211 that is integral with a front secondary balancer 21 that is supported through a needle bearing in the center of the balancer shaft 10 so as to be relatively rotatable. The secondary balancer 21 is driven to rotate at twice the speed of the crankshaft 8.

A left cover 22 that covers the left half 2 of the crankcase 3, and a cooling water pump cover 23 that further covers the outside thereof.
A cooling water pump 24 connected to and driven by the left end of the balancer shaft 10 is housed inside.

As is clear from FIGS. 4 and 5, the crankshaft 8 supported by the left and right side walls 11 and 21 of the crankcase 1 is provided with a pair of balance weight parts 81 in the center, and both balance weight parts 81 Connecting rod 26 to crank pin 25
The big end of is connected. A well-known alternator 27 that also serves as a flywheel is attached to the left end of the crankshaft 8.

Right cover 2 covering right half 1 of the crankcase
A pump drive shaft 29 coaxially connected to the right end of the crankshaft 8 is rotatably supported at 8, and a trochoid type scavenge pump 30 and a feed pump 31 are supported on this pump drive shaft 29. The scavenge pump 30 includes an outer rotor 32 that is rotatably housed in a recess formed on the inner surface of the right cover 28, and an inner rotor 33 that is coupled to the pump drive shaft 29 and meshes with the outer rotor 32 in an eccentric state. , 33 are closed by a cover plate 34.

The feed pump 31 includes an outer rotor 35 rotatably housed in a recess formed on the outer surface of the right cover 28, and an inner rotor 36 connected to the pump drive shaft 29 and meshing eccentrically with the outer rotor 35.
The outer surfaces of both rotors 35 and 36 are covered with an oil pump cover 37.
is occluded by A filter chamber 39 housing a filter 38 is formed in the right cover 28 so as to be located above the feed pump 31, and an opening of the filter chamber 39 is covered by an oil pump cover 37. The capacity of the scavenge pump 30 is set to be larger than the capacity of the feed pump 31 so that the level of oil remaining at the bottom of the crankcase 3 does not rise.

As is clear from FIG. 6, the output gear 17 of the crankshaft 8 is connected to the main shaft 1 of the mission M.
The transmission of driving force between the crankshaft 8 and the main shaft 11 is controlled by turning the clutch 40 on and off. The clutch 40 is housed in a clutch housing part 281 formed to protrude outward from the right cover 28. In order to provide the input gear 41 of the clutch 40 with a rear primary balancer, the output gear 17 of the crankshaft 8 and the input gear 41 of the clutch 40 have the same number of teeth, and the primary balancer of the crankshaft 8 and the main shaft 11 of the transmission M is the same. The ratio is set to 1. As a result, the diameter of the clutch 40 is reduced, and a sufficient capacity of the oil tank 51, which will be described later, is ensured.

The main shaft 11 and countershaft 12 of the mission M are provided with a plurality of gear trains G1 to G5 for selectively establishing desired gear positions. A change spindle shaft 42 rotated by a shift change pedal (not shown) is connected to the shift drum 16 via a change mechanism 43, and a shift fork shaft 1 is formed in cam grooves 161 to 163 provided on the outer periphery of the shift drum 16.
Three shift forks 441 slidably supported on
The proximal ends of ~443 engage. and shift fork 4
41 to 443, any of the gear trains G
A desired gear position is established by selectively engaging G1 to G5. An idler gear 45 that meshes with the balancer drive gear 20 of the crankshaft 8 is supported on the main shaft 11 so as to be relatively rotatable via a needle bearing.
A balancer gear 461 integrated with the rear secondary balancer 46, which is supported through a needle bearing so as to be relatively rotatable, meshes with the rear secondary balancer 46. As a result, the rear secondary balancer 46 is driven to rotate at twice the speed of the crankshaft 8.

As is clear from FIGS. 3 and 4, an oil reservoir 47 is formed at the bottom of the crankcase 3 in which oil that lubricates various parts of the internal combustion engine E remains, and a strainer 48 is disposed inside the reservoir. Ru. The rear right side of the crankcase 3 is partitioned into left and right sides by the side wall 11 of the crankcase right half 1 and the right cover 28, and the bottom of the crankcase right half 1 and the right cover 28 surrounds the rear of the clutch 40. The oil tank 5 is partitioned on the front side by a partition wall 49 that reaches up to
1 is formed. In order to increase the volume of the oil tank 51, the side wall 11 of the crankcase right half 1 that defines the left side of the oil tank 51 has a
A convex portion 511 that bulges out to the side is formed.

As shown in FIGS. 1 and 4, between the side wall 11 of the right crankcase half 1 and the side wall 21 of the left crankcase half 2, the outer periphery of the balance weight part 81 of the crankshaft 8 and the shift drum A pair of arc-shaped ribs 52 and 53 are formed along the outer periphery of 16. The oil tank 51 includes a through hole 12 formed in the right side of the crankcase 11 , an auxiliary oil chamber 54 formed at the bottom of both ribs 52 and 53 , and a left side of the crankcase 21 .
The alternating current generator 27 is communicated with the inside of the left cover 22 in which the alternator 27 is housed through a through hole 22 formed in the left cover 22, whereby the oil level in the oil tank 51 is maintained constant.

As shown in FIG. 2, an oil passage L1 extending forward and upward is formed in the convex portion 282 protruding from the right cover 28, and the upper space of the strainer 48 of the oil reservoir 47 is accessed through this oil passage L1. communicates with the suction port of the scavenge pump 30. As shown in FIGS. 3 and 6, the oil passage L2 connected to the discharge port of the scavenge pump 30 extends rearward inside the right cover 28, and connects to the right crankcase half 1 forming the partition wall 49 of the clutch 40. It is connected to an arc-shaped oil passage L3 formed on the mating surface of the right cover 28, and its end is connected to an oil return port 512 formed at the upper end of the oil tank 51. The arc-shaped oil passage L3 branches laterally, and from there the shift fork shaft 1
An oil passage L6 formed inside the main shaft 11 via an oil passage L4 formed inside the main shaft 11 and an oil passage L5 formed on the mating surface of the left half part 2 of the crankcase 2 and the left cover 22.
communicate with. Further, the arc-shaped oil passage L3 branches laterally at another position and communicates with an oil passage L7 formed inside the countershaft 12.

As shown in FIG. 2, an oil passage L8 formed in a convex portion 282 protruding from the right cover 28 and parallel to the oil passage L1 communicates with the suction port of the feed pump 31. As shown in FIG. 4, the discharge port of the feed pump 31 reaches the filter chamber 39 from the oil passage L9 formed in the oil pump cover 37, passes through the filter 38 from the outside in the radial direction to the inside, and then enters the oil pump cover 37. It branches into the formed upward oil path L10 and downward oil path L11. The downward oil passage L11 reaches the crank pin 25 via an oil passage L12 passing through the inside of the pump drive shaft 29 and an oil passage L13 formed inside the crankshaft 8. On the other hand, the upward oil passage L10 reaches the mating surface of the crankcase right half 1 and the right cover 28 via an oil passage L14 that branches laterally inside the crankcase right half 1, and a groove is formed on the mating surface. The valve mechanism and the like provided in the cylinder head 5 are lubricated via the rearward oil passage L15 and an oil passage (not shown). Further, the forward oil passage L16 formed on the mating surface is different from the oil passage L17 formed on the right cover 28 as shown in FIG.
An oil passage L formed inside the balancer shaft 10 via
Connects to 18.

Next, the operation of the embodiment of the present invention having the above-described configuration will be explained.

When the crankshaft 8 rotates due to the operation of the internal combustion engine E, the pump drive shaft 29 connected to the right end of the crankshaft 8 rotates, and the scavenge pump 3 rotates.
0 and feed pump 31 are driven simultaneously.

Outer rotor 32 of scavenge pump 30
Due to the rotation of the inner rotor 33, the oil remaining in the oil reservoir 47 formed at the bottom of the crankcase 3 is suctioned, passes through the strainer 48, and flows from the oil passage L1 formed in the right cover 28 to the suction port of the scavenge pump 30. Inhaled. Most of the oil pumped from the discharge port of the scavenge pump 30 to the oil passage L2 is returned to the oil tank 51 via the oil passage L3 and the oil return port 512. On the other hand, a part of the oil reaches an oil passage L6 formed inside the main shaft 11 from the oil passage L3 via an oil passage L4 and an oil passage L5, and lubricates the gear trains G1 to G5 supported on the outer periphery of the oil passage L6. At the same time, oil path L3
The oil supplied to the countershaft 12 branches into an oil passage L7 formed inside the countershaft 12, and lubricates the gear trains G1 to G5 supported on the outer periphery of the oil passage L7.

On the other hand, oil sucked from the oil tank 51 by the rotation of the outer rotor 35 and inner rotor 36 of the feed pump 31 is sucked into the suction port of the feed pump 31 from an oil passage L8 formed in the right cover 28. From the discharge port of the feed pump 31 to the oil path L
The oil that has passed through the filter 38 via the oil passage L
11, Crank pin 2 via oil path L12 and oil path L13
Lubricate 5. In addition, a part of the oil that has passed through the filter 38 lubricates the valve mechanism etc. provided in the cylinder head 5 via oil passages L10, L14, and L15, and also lubricates the valve mechanism etc. provided in the cylinder head 5 through oil passages L10, L14, and L15. The oil reaches the oil passage L18 formed inside the balancer shaft 10 through the oil passage L18, and lubricates the front secondary balancer 21 supported on the outer periphery thereof.

7 and 8 show a second embodiment of the present invention, with FIG. 7 being an overall side view of the internal combustion engine corresponding to FIG. 1, and FIG. 8 being a sectional view corresponding to FIG. 6. .

This embodiment is characterized in that a protrusion 513 formed at the rear of the oil tank 51 is made to protrude further toward the left half 2 of the crankcase than the protrusion 511 of the first embodiment. There is. As a result, the left side of the crankcase 2
The capacity of the oil tank 51 can be further increased by effectively utilizing the dead space.

The oil tank 51 of this embodiment is also provided with a baffle rib 55 extending forward from the rear wall 50 of the crankcase right half 1 and the right cover 28.
Fluctuations in the oil level in the oil tank 51 are regulated by this. The baffle ribs 55 may be inclined so that the tips thereof are directed upward so that bubbles caught in the oil can be separated.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various small designs can be made without departing from the scope of the invention described in the claims. It is possible to make changes.

For example, in the embodiment, the scavenge pump 30
Although the main shaft 11 and the countershaft 12 are lubricated by a portion of the oil returned to the oil tank 51 from the oil tank 51, the scavenge pump 30 may simply return the oil to the oil tank 51. Furthermore, the scavenge pump 30 and the feed pump 31 are not limited to trochoid type pumps, but may also be an internal gear pump that has a partition member between an internal gear and an external gear, or an external gear pump that combines two external gears. Other types of pumps can be used. The present invention is also applicable to multi-cylinder internal combustion engines.

[0031]

As described above, according to the first feature of the present invention, a clutch is provided at one end of the main shaft provided above the crankshaft, and a dead space below the clutch is created within the crankcase. Since the oil tank is formed in the crankcase, piping that would be required if the oil tank is provided outside the crankcase can be omitted. As a result, the structure of the oil tank and its piping system is simplified, making it possible to save manufacturing costs, weight, and space.

According to the second feature of the present invention, the primary ratio of the crankshaft and the main shaft is set to 1.
By doing this, the diameter of the clutch can be reduced, so it is possible to secure sufficient space for forming an oil tank inside the crankcase.

According to the third feature of the present invention, since the oil passage leading from the scavenge pump to the oil tank is formed on the mating surface of the crankcase and the crankcase cover, the oil passage can be connected without providing any special piping. can be formed.

[Brief explanation of drawings]

FIG. 1 is an overall side view of an internal combustion engine showing a first embodiment of the present invention.

[Figure 2] Enlarged view of main parts of Figure 1

[Figure 3] Enlarged view of main parts of Figure 1

[Figure 4] Cross-sectional view taken along line 4-4 in Figure 1

[Figure 5] Cross-sectional view taken along line 5-5 in Figure 1

[Figure 6] Cross-sectional view taken along line 6-6 in Figure 3

FIG. 7 is an overall side view of an internal combustion engine corresponding to FIG. 1 showing a second embodiment of the present invention.

[FIG. 8] A cross-sectional view corresponding to FIG. 6 above.

[Explanation of symbols]

3...Crankcase 8...Crankshaft 11...Main shaft 28...Right cover (crankcase cover) 30...Scavenge pump 31...Feed pump 47...Oil reservoir 51...Oil tank L3... Oil road M...Mission

Claims (3)

[Claims] 1. A scavenge pump (30) that returns oil accumulated in an oil reservoir (47) at the bottom of a crankcase (3) to an oil tank (51);
51) in an oil tank structure for a dry sump lubricated internal combustion engine, which is equipped with a feed pump (31) that supplies oil therein to each lubricating section, and is connected to a crankshaft (8) supported by the crankcase (3). The main shaft (11) of the transmission (M) is disposed above the crankshaft (8), and a clutch (40) is provided at one end of the main shaft (11), and the An oil tank structure for a dry sump lubricated internal combustion engine, characterized in that the oil tank (51) is formed in a space below a clutch (40). 2. The oil tank structure for a dry sump lubricated internal combustion engine according to claim 1, wherein the primary ratio of the crankshaft (8) and the main shaft (11) is 1. 3. An oil passage (L3) leading from the scavenge pump (30) to the oil tank (51) is formed on a mating surface of the crankcase (3) and the crankcase cover (28). An oil tank structure for a dry sump lubricated internal combustion engine according to item 1.