JP3368636B2 - Oil passage structure of oil-cooled engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil passage structure for an oil-cooled engine in which a cylinder portion is inclined forward of a vehicle body and an exhaust port is provided forward.

[0002]

2. Description of the Related Art Conventionally, in an oil-cooled engine, cooling oil is returned from the inside of a cylinder head to a crankcase as described in (1) and (2) below.

(1) As shown in FIG. 8, the cylinder head 12 of the engine 10 and the crankcase 14 are connected by a pipe 18 separate from the cylinder portion 16,
Some pipes 18 are used as oil return passages. The oil returned through the pipe 18 once collects in the oil sump 14a below the crankcase 14,
It is sent to a cylinder head cooling system 24 by an oil pump 22 via an oil strainer 20. Further, it is also sent to the oil lubrication system 26. That is, it is sent to the crankshaft bearing 32a and the camshaft 32b in the cylinder head 12 for lubrication via the oil cooler 28 and the oil filter 30.

(2) Further, as shown in the end view of the cylinder portion 34 on the cylinder head side in FIG.
4, an oil return passage 36 is integrally formed with the cylinder portion 34 between the cam chain tunnel 34a and the cylinder bore 34b (see, for example, the actual opening 6).
2-145927). In the figure, reference numeral 38 is a bolt through hole.

[0005]

In the structure of the oil return passage of the above (1), since the pipe 18 is a separate type, the degree of freedom of layout is large, but on the other hand, the pipe is separate from the engine. The number of parts is increased and the assemblability is deteriorated, resulting in higher cost because the related parts such as the seal structure are required in the mounting part of the pipe 18 and the like. There is a problem.

On the other hand, in the structure of the oil return passage of (2), the problem of the oil return passage 18 of (1) is solved because the oil return passage 36 is integrated with the cylinder portion 34. However, due to the layout of the oil return passage 36, the oil returned from the passage 36 to the crank chamber is likely to directly hit the crank, and problems such as increase in mechanical loss (mechanical loss) and oil bubbling are likely to occur. In addition, due to the layout of the oil return passage 36, as shown in FIG. 9, it is inevitable that the distance L between the cylinder bore 34b and the cam chain tunnel 34a increases, so that the dimension of the engine in the crankshaft direction increases. ,
There is a problem that the size of the engine is increased.

Incidentally, in connection with the present invention, JP-A-64-5
Japanese Patent No. 6910 discloses a cylinder head cooling structure for supplying cooling oil and lubricating oil to the upper portion of the cylinder head along the camshaft through the same supply passage. However, in this cooling structure, the cooling oil and the lubricating oil are sent through the same supply passage in the cylinder head, and the cooling oil jet port and the lubricating oil jet port are provided in the passage. Therefore, it has not been possible to inject the cooling oil or the lubricating oil to an appropriate and sufficiently necessary place. Further, it is particularly required to sufficiently cool the exhaust port side of an engine that requires cooling, but no technology has conventionally been proposed to meet this requirement.

The present invention has been made in order to solve the above-mentioned conventional problems, and it is possible to prevent an increase in the number of parts, prevent the engine from increasing in size and mechanical loss, and to properly and adequately operate the engine. An object is to provide an oil passage structure of an oil-cooled engine that can be cooled.

[0009]

In order to solve the above-mentioned problems, the present invention has the following constitution. That is, the invention of claim 1 is an oil-cooled engine in which the upper portion of the cylinder portion (40) is inclined forward and the lower portion is inclined rearward, and the exhaust port (42) is provided forward. An oil passage structure for supplying cooling oil into the oil chamber (44a) of the head (44) and returning the supplied cooling oil to the crankcase (46), which is the same as the cylinder head (44). Supply side oil passage (4
The cooling oil passage (50) and the lubricating oil passage (52, 52) communicating with 8) are provided as separate bodies, and the cooling oil passage (50) is located substantially above the cylinder bore (54), and The lubricating oil passages (52, 52) are located near the valve mechanism shaft (56). Further, a first cooling oil return passage (57) that opens the oil chamber (44a) to the cylinder part (40) side is formed at the side of the exhaust port (42) of the cylinder head (44). 40) at the side of the exhaust port (42), the first cooling oil return passage (57) and the crankcase (46).
A second cooling oil return passage (58) is provided integrally with the cylinder portion (40). Further, at least one of the upper surface of the cylinder portion (40) and the lower surface of the cylinder head (44), a recess (60) connected to the first and second oil return passages (57 and 58).
Is formed.

The invention according to claim 2 provides the cooling oil return passages (57, 58) according to claim 1, wherein the cooling oil return passages (57, 58) are opened on the lower surface of the cylinder head (44). Position (57a) and cylinder part (40)
The opening (5) of the second cooling oil return passageway (58) on the upper surface
8a) positions are offset from each other. Further, in the invention of claim 3 according to claim 1 or 2, the cooling oil passage (50) is provided on the intake valve port (62) side.

[0011]

In the present invention, the cylinder head (44)
In addition, the cooling oil passage (50) and the lubricating oil passage (52, 52) communicating with the same oil passage (48) are provided as separate bodies, and the cooling oil passage (50) is almost the cylinder bore (54). ), And the lubricating oil passages (52, 52) are positioned near the valve mechanism shaft (56), the cooling oil is transferred to the cylinder head (4).
The oil for lubrication can be appropriately and sufficiently supplied to the valve mechanism shaft (for example, the cam shaft) mainly in the cylinder bore 4) for cooling and lubrication. Further, since the upper part of the cylinder part (40) is inclined forward and the lower part is inclined rearward, the cylinder part (40) is supplied to the cooling oil cylinder head and flows toward the exhaust port side, so that efficient cooling can be achieved.

Further, a first cooling oil return passage (57) for opening the oil chamber (44a) to the cylinder part (40) side is formed at the side of the exhaust port (42) of the cylinder head (44), The first cooling oil return passage (5) is provided on the side of the exhaust port (42) of the cylinder portion (40).
Since the second cooling oil return passage (58) connecting between the crankcase (46) and the crankcase (46) is provided integrally with the cylinder portion (40), the cylinder head (44) and the cylinder are particularly likely to be highly heated. Exhaust port (4)
2) The side part can be cooled surely and sufficiently. Further, the first portion is provided on at least one of the upper surface of the cylinder part (40) and the lower surface of the cylinder head (44).
Since the concave portion (60) connected to the second oil return passage (57 and 58) is formed, this space serves as an oil reservoir, and the accumulated oil exhausts the cylinder head (44) and the cylinder portion (40). Mouth (4
2) The side can be cooled sufficiently.

Each cooling oil cooling oil return passage (57, 58) is provided with an opening (58a) of the first cooling oil return passage (57) on the lower surface of the cylinder head (44).
The position and the position of the opening (58a) of the second cooling oil return passage (58) on the upper surface of the cylinder part (40) may be offset from each other. With this configuration, the cooling oil once enters the concave portion (60) through the lower surface opening (57a) and collides with the inner wall of the concave portion (60) or the upper surface of the cylinder portion (40). Is loosened and its flow direction is changed, the flow velocity is further loosened and is accumulated in the recess (60).
After that, the cooling oil in the recess (60) is directed to the upper surface opening (58a) and further the opening (58a).
To the second cooling oil return passage (58), the flow is changed and the flow velocity is relaxed. Therefore, the cooling oil collides with the inner wall of the space formed in the recess (60) and the flow direction changes, so that the flow velocity is sufficiently slowed and the cooling oil reliably accumulates in the recess (60) and flows slowly. become. As a result, the cylinder head (44) and the cylinder part (40) can be cooled reliably and sufficiently.

The cooling oil passage (50) is connected to the intake valve port (6
If it is provided on the 2) side, the engine of the present invention is inclined to the front exhaust port side, so that the cooling oil can flow from the portion near the intake valve to the exhaust valve, and this oil flow reliably and sufficiently (44) can be cooled.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to an oil-cooled engine mounted on a motorcycle. FIG. 1 shows the overall construction of the motorcycle according to the embodiment, and FIGS. 2 to 7 show the detailed construction of the cylinder head 44 and the cylinder portion 40 of the oil-cooled engine.

As shown in FIG. 1, the motorcycle has a cylinder portion 40 in which an upper portion is inclined forward and a lower portion is inclined rearward, and an exhaust port 42 is provided forward.
Oil-cooled engine 43 with cylinder overhead cam (OHC)
Equipped with. 2 to 4 are a plan view showing the cylinder head 44 of the oil-cooled engine in detail, a sectional view taken along the line DD of FIG. 2, and a bottom view.

As shown in FIGS. 2 to 4, in the oil-cooled engine of this embodiment, a cooling oil passage 50 for supplying cooling oil into the oil chamber 44a of the cylinder head 44 and a supply into the oil chamber 44a. A first cooling oil return passage 57 and a second cooling oil return passage 58 for returning the cooled cooling oil to the crankcase 46.
Is an oil passage structure consisting of

A spark plug hole 66 is formed in the cylinder head 44 at a central portion of a partition wall 64 covering the cylinder bore 54 shown by a broken line in FIG. An upper partition 66a has an insertion partition so that the spark plug body can be inserted therein. In addition, the upper portion 66 of the spark plug hole 66
A space outside the partition wall forms an oil chamber 44a. The upper 66a partition wall is supported by a support wall 68.

Further, in FIG. 2, the spark plug hole 6
6, an exhaust valve hole 70 (on the exhaust side) (a tappet hole that can be seen in FIG. 2 is the exhaust valve hole 70 below this), and an intake valve hole on the upper side (on the intake side). 62 (Fig. 2
What is visible is a tappet hole, and an intake valve hole 62 is formed below this tappet hole). These valve holes 62, 70
A cam journal portion 72 that supports a cam shaft for driving each valve is formed in the vicinity of. The cam journal portion 72 is formed with a groove 72a through which lubricating oil passes. The space on the left side in FIG. 2 is a cam chain chamber 74 in which the cam chain is arranged.

An oil passage 4 for supplying oil from the same supply source is provided above the cylinder head 44.
8, one cooling oil passage 50 and one cooling oil passage 2
The two lubricating oil passages 52, 52 are provided separately. In this case, the cooling oil passage 50 and the lubricating oil passages 52, 52 are both formed parallel to each other along the crankshaft. The oil passage 48 is formed along the vertical direction of the cooling oil passage 50 and the lubricating oil passages 52, 52.
0 and the lubricating oil passages 52, 52 are formed on the same plane. Further, the cooling oil passage 50 is located substantially on the side of the intake valve hole 62 of the spark plug hole 66 on the cylinder bore 54 and within the valve holding angle of the intake valve and the exhaust valve, and when viewed in the crankshaft direction. The hole is formed so as to extend from the side surface on the opposite side of the cam chain chamber 74 to the vicinity of the cam chain chamber 74. In the cooling oil passage 50, injection nozzles 50a are formed so as to face the oil chamber 44a at appropriate intervals and inject the cooling oil onto the upper surface of the cylinder head partition wall 64.

The lubricating oil passages 52, 52 are located in the vicinity of and outside the cam shaft (passing through the cam journal portion 72) on the exhaust valve hole 70 side and the intake valve hole 62 side, respectively, and the cam chain chamber The hole 74 is formed from the side surface of the crankshaft 74 on the opposite side in the crankshaft direction to the vicinity of the cam journal portion 72 on the cam chain chamber 74 side. The cooling oil passages 50 and the lubricating oil passages 52 can be formed through the pipes after the holes are formed in the cylinder head 44.

The oil distribution ratio between the cooling oil passage 50 and the lubricating oil passages 52, 52 can be appropriately set by appropriately selecting the diameters of the passages. Therefore, in the conventional oil-cooled engine in which the cooling oil passage and the lubricating oil passage are integrated, the cooling oil and the lubricating oil cannot be properly selected, whereas the engine according to the present embodiment has the supply side. Even though the oil passage is integrated, each oil can be appropriately and sufficiently supplied.

A partition wall 6 covering the cylinder bore 54 is also provided.
4 includes a partition wall 64a for partitioning the partition upper surface 64 for each cylinder, a cam chain chamber 74, and an oil chamber 4
A partition wall 64b for partitioning between the 4a is formed. Further, wall-shaped ribs 71 are provided for allowing the cooling oil to flow from the partition walls 64a and 64b toward the outer peripheral wall 66a of the spark plug hole 66. As shown in FIGS. 2 and 3, the rib 71 has a height substantially equal to the height of the opening of the injection nozzle 50a. Further, the ribs 71 are formed in the exhaust valve holes 70 from the center line of each spark plug hole 66 when viewed from above the cylinder.
It is located slightly closer to the side. Further, the rib 71 has an end portion on the outer peripheral wall 66a side that substantially coincides with the shaft 50a1 of the injection nozzle 50a in a side view in the direction perpendicular to the crankshaft, and
The outer peripheral wall 66a is formed to be slightly inclined toward the exhaust side so that the end portion is closer to the exhaust valve hole 70 side than the partition wall 64a mounting side.

Further, the exhaust port 42 of the cylinder head 44
A first cooling oil return passage 57 that opens the oil chamber 44a toward the cylinder portion 40 is integrally formed in the side portion. In the embodiment, the opening of the first cooling oil return passage 57 is formed at a portion substantially opposite to the injection nozzle 50a with the spark plug hole 66 interposed therebetween and in the vicinity of the exhaust valve hole 70. In addition, the injection nozzle 50a and the first
There are four cooling oil return passages 57. Further, the first cooling oil return passage 57 has a substantially deformed rectangular cross section, and its axis is along the piston sliding direction.
As shown in FIG. 5, the cooling oil return passage 57 has an opening (indicated by reference numeral 57a) on the lower surface of the cylinder head. However, the present invention is not limited to this, and can be formed in an appropriate cross section and axis.

5 (a) and 5 (b) show the cylinder portion 40.
Is a top view, a bottom view, and FIG. 6 is a sectional view taken along the line EE of FIG. As shown in FIGS. 5 and 6, the cylinder portion 4
A second cooling oil return passage 58, which connects the first cooling oil return passage 57 and the crankcase 46, is provided integrally with the cylinder portion 40 on the side of the exhaust port 42 of 0.

Further, a concave portion 60 is formed on the upper surface of the cylinder portion 40 so as to be connected to the first and second oil return passages 57 and 58 when the cylinder portion 40 is assembled with the cylinder head 44. In this case, the cooling oil return passage 58 has the opening 57a position of the first cooling oil return passage 57 on the lower surface of the cylinder head 44 and the opening 58a position of the second cooling oil return passage 58 on the upper surface of the cylinder portion 40. Are formed to be offset from each other. As shown in FIG. 5, the cooling oil return passage 58 has a circular cross section, and as shown in FIG.
It passes through 0. Further, a sleeve 75 is fitted in the cylinder portion 40, and the inside of the sleeve 75 serves as a cylinder bore 54. The recess 60 has a position corresponding to the opening 57 a of the first oil return passage 57. A shape is formed along the outer peripheral end of the sleeve 75 and in contact with the outer edge of the sleeve 75 from that position to the vicinity of the second oil return passage 58.

A gasket 76 is interposed between the lower surface of the cylinder head 44 and the upper surface of the cylinder portion 40. The gasket 76 is formed with a hole 76a having the same shape as the opening of the recess 60, and holes 76b, 76c, and 76d corresponding to the cam chain chamber 74, the cylinder bore 54, or the mounting bolt hole.

The operation of the embodiment will be described below. The oil-cooled engine of the embodiment has a cylinder head 4 shown in FIGS. 2 to 4.
4 and the cylinder portion 40 shown in FIGS. 5 to 6 are assembled by interposing the gasket of FIG. The oil flow will be described with reference to FIGS. 2 to 7.

As shown in FIGS. 2 to 4, oil for both cooling and lubrication is supplied to the oil passage 48 from an oil pump (not shown). The supplied oil passes through the oil passage 48 and then flows into the cooling oil passage 50 and the lubricating oil passage 52 separately. The oil in the cooling oil passage 50 is sprayed as cooling oil from each spray nozzle 50a into the oil chamber 44a.

That is, the cooling oil is injected toward the intake valve hole 62 side on the upper surface of the cylinder bore upper partition wall 64, as shown by the arrow in FIG. 2 and FIG. 3, and toward the exhaust side on the upper partition wall 64. Flowing. This oil flow is rib 71
Is turned to the direction of the spark plug hole 66, further passes through the vicinity of the side surface of the outer peripheral wall 66a of the spark plug hole 66, and flows into the first cooling oil return passage 57 so as to go around the rib 71.

The cooling oil that has flowed into the first cooling oil return passage 57 sufficiently cools the portion of the cylinder head 44 on the side of the exhaust port 42 which is likely to become highly heated when passing through it. In addition, the cooling oil passes through the first cooling oil return passage 57, from the lower surface opening 57 a of the passage, through the hole 76 a of the gasket 76, and the cylinder portion 4.
0 flows into the space formed by the depression 60 on the upper surface. The cooling oil that has flowed in once enters the recess 60 from the lower surface opening 57a and collides with the inner wall of the recess 60, whereby the oil flow velocity is slowed and the flow direction is changed, so that the flow velocity is further relaxed. After that, the cooling oil in the recess 60 is directed toward the upper opening 58a of the cylinder portion of the second cooling oil return passage 58, and the opening 5 is further opened.
8a flows into the second cooling oil return passage 58. At this time, the flow rate of the oil is changed, so that the flow velocity thereof is reduced.

Therefore, the cooling oil is used for the recess 6
Since it collides with the inner wall of the space created by 0 and the flow direction changes, the flow velocity is sufficiently slowed down and the recess 60 is surely formed.
It accumulates inside and flows slowly. This allows
The valve seat of the cylinder head 44 and the cylinder portion 40
The inner side of the sleeve on the exhaust side can be cooled reliably and sufficiently. The oil that has passed through the second cooling oil return passage 58 enters the crank chamber. Since the second cooling oil return passage 58 is provided at the portion on the exhaust port 42 side where heat is easily generated, the cooling oil flowing therethrough causes
The cylinder part 40 can be cooled sufficiently. The oil distributed from the oil passage 48 on the supply side to the lubricating oil passage 52 is supplied to the groove 72a of the cam journal portion 72.

In the above embodiment, the recess 60 is formed on the upper surface of the cylinder portion 40. However, the formation of the recess of the present invention is not limited to this, and it may be provided on the lower surface of the cylinder head 44. It can be provided on both the upper surface of the portion 40 and the lower surface of the cylinder head 44.

[0034]

As described above, according to the present invention, since no pipe is used in the oil return passage, cooling can be performed without increasing the number of parts. Further, since the oil return passage is not provided on the cam chain chamber side, it is not necessary to widen the space between the cylinder bore and the cam chain chamber, and it is possible to avoid an increase in size of the engine. Further, even though the oil enters the crank chamber, the oil can be introduced into the crank chamber from the exhaust side, so that the oil can be prevented from hitting the crankshaft and the mechanical loss can be prevented. Further, since the exhaust side of the engine where the heat tends to become high can be focused on the oil cooling, the engine can be cooled appropriately and sufficiently.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a motorcycle equipped with an engine according to an embodiment of the present invention.

FIG. 2 is a plan view of a cylinder head of the engine according to the embodiment.

FIG. 3 is a side sectional view taken along the line DD of FIG.

FIG. 4 is a bottom view of the cylinder head of the engine according to the embodiment.

5A is a plan view of a cylinder portion of an engine according to an embodiment, and FIG. 5B is a bottom view thereof.

FIG. 6 is a sectional view taken along line EE of FIG.

FIG. 7 is a plan view of the engine gasket according to the embodiment.

FIG. 8 is a structural example of a conventional oil-cooled engine.

FIG. 9 is an explanatory diagram of another configuration example of a conventional oil-cooled engine.

[Explanation of symbols]

40 cylinder part 42 Exhaust port 44 cylinder head 44a oil chamber 48 Supply side oil passage 50 Cooling oil passage 50a injection nozzle 52 Oil passage for lubrication 54 cylinder bore 56 Cam shaft (an example of valve mechanism shaft) 57 First Cooling Oil Return Passage 57a opening 58 Second cooling oil return passage 58a opening 60 dents 62 Intake valve hole 64 cylinder head bulkhead

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Claims (3)

(57) [Claims] 1. A cylinder head (44) in an oil-cooled engine in which an upper part of a cylinder portion (40) is inclined forward and a lower part is inclined rearward and an exhaust port (42) is provided forward. Has an oil passage structure for supplying cooling oil into the oil chamber (44a) and returning the supplied cooling oil to the crankcase (46). The cooling oil passage (50) communicating with the passage (48) and the lubricating oil passage (52, 52) are provided as separate bodies, and the cooling oil passage (50) is substantially the cylinder bore (54).
Oil passage for lubrication (52, 52) located above
Is a first cooling oil which is located near the valve mechanism shaft (56) and which opens an oil chamber (44a) on the side of the exhaust port (42) of the cylinder head (44) on the side of the cylinder (40). A return passage (57) is formed, and a second passage connecting the first cooling oil return passage (57) and the crankcase (46) is formed on the side of the exhaust port (42) of the cylinder portion (40). A return passage (58) for cooling oil is provided integrally with the cylinder part (40), and the upper surface of the cylinder part (40) or the cylinder head (4) is provided.
4) An oil passage structure for an oil-cooled engine, wherein a recess (60) connected to the first and second oil return passages (57 and 58) is formed on at least one of the lower surfaces. 2. A cooling oil return passage (57, 58) for each cooling
Is the opening (57a) position of the first cooling oil return passage (57) on the lower surface of the cylinder head (44) and the second cooling oil return passage (58) on the upper surface of the cylinder portion (40).
2. The oil passage structure for an oil-cooled engine according to claim 1, wherein the position of the opening (58a) of the oil is offset from each other. 3. The cooling oil passage (50) is provided on the intake valve port (62) side.
Alternatively, the oil passage structure of the oil-cooled engine according to item 2.