JP3147723B2 - Oil pump sprocket cover for internal combustion 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 pump sprocket cover for an internal combustion engine, and more particularly to an internal combustion engine that reduces the flow rate of oil near the outlet side of the oil pump sprocket cover to reduce the amount of oil mist and aeration of oil. The present invention relates to an oil pump sprocket cover.

[0002]

2. Description of the Related Art In an internal combustion engine mounted on a vehicle, oil is circulated by an oil pump for lubrication and cooling of various parts of the engine. Oil is stored in an oil pan below the internal combustion engine, is supplied to various parts of the engine, lubricates and cools various parts of the internal combustion engine, and is returned to the oil pan.

[0003] An oil pump sprocket cover for an internal combustion engine is disclosed in Japanese Patent Publication No. 63-16569. An oil pump sprocket cover disclosed in this publication includes a sprocket attached to a flange formed on a side wall of the oil pump body on a sprocket arrangement side so as to surround a sprocket attached to a drive shaft extending from the oil pump body. A cover having at least an upper edge positioned above a maximum level of oil and a plurality of long holes formed along a virtual circle, each of the long holes extending in a circumferential direction of the virtual circle; A wall portion attached to the end surface of the flange portion through a bolt through each of the long holes and a guide portion disposed along the drive chain over a range from the sprocket on the sprocket entry side of the drive chain on the sprocket. And a wear-resistant elastic material is attached to the guide part, and it is in constant contact with the drive chain. To apply tension to the drive chain, and the drive sprocket of the oil pump disposed in the oil was hung on the drive sprocket without causing agitation, scattering, or waving of the oil surface during rotation. The slack of the drive chain is also prevented.

[0004] Furthermore, there is one disclosed in Japanese Patent Application Laid-Open No. 5-332113. The mounting structure of the oil pump disclosed in this publication has a structure in which the oil pump is disposed in the oil pan and one of the pump sprockets is disposed near the pump sprocket in order to prevent the oil in the oil pan from being stirred when the oil pump is driven. Provide a cover part surrounding the part,
In addition to preventing poor oil suction at low temperatures, oil agitation by the pump sprocket and the pump driving chain is prevented.

[0005]

In the conventional internal combustion engine, as shown in FIG. 9, an oil pan 112 is provided below the internal combustion engine 102, and an oil pan (not shown) is provided in the oil pan 112 and in the crankcase 110. A pump is provided.

The oil pump sprocket cover 144 surrounding a part of the oil pump sprocket 140 of the oil pump is
And an oil pump chain 142 as a drive chain.
Oil pump sprocket cover 1 on the inlet side where air enters
44 formed between the oil pump chain 142 and the oil pump chain 142.
The size of the gap S1 and the oil pump sprocket cover 1
The size of the second gap S2 formed between the oil pump chain 142 and the oil pump sprocket cover 144 on the outlet side where the oil pump chain 142 exits from the inside is substantially the same.

[0007] As a result, the outlet side inner surface of the oil pump sprocket cover 144 is close to the oil pump chain 142, and the outlet side inner surface functions as a guide for oil in the oil pump sprocket cover 144, that is, a launch pad. A large amount of oil mist is generated in the case 110, and it is necessary to increase the capacity of a breather chamber (not shown) in the cylinder head cover 108.

The oil scooped up by the oil pump chain 142 from the bottom of the oil pump sprocket cover 144 is directly affected by the oil pump chain 142 in the vicinity of the second gap S2, and the speed is not reduced. When the oil flows out of the second gap S2, the crankcase 110
As the amount of oil mist in the oil increases, the aeration in the oil increases, and the amount of aeration in the oil sucked by the oil strainer increases, resulting in a disadvantage that the lubrication performance and reliability of the engine decrease.

[0009]

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned disadvantages, the present invention connects an oil pump driving sprocket fixed to an end of a crankshaft and an oil pump sprocket by a driving chain. An oil pump driven by the rotational force of the crankshaft is provided, and an oil pump sprocket cover of an internal combustion engine is provided with an oil pump sprocket cover surrounding the oil pump sprocket of the oil pump. A first gap is formed between the oil pump sprocket cover on the inlet side where the chain enters and the drive chain, and a second gap is formed between the oil pump sprocket cover on the outlet side and the drive chain where the drive chain exits from inside the oil pump sprocket cover. The second gap is formed to be larger than the first gap in order to reduce the flow rate of the oil near the outlet side of the oil pump sprocket cover to reduce the amount of oil mist and the aeration of the oil. Features.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION
When the crankshaft rotates, the oil pump driving sprocket fixed to the crankshaft rotates, and the rotational force of the oil pump driving sprocket rotates the oil pump sprocket through the pump driving chain, thereby causing the oil pump to rotate. When the oil pump is driven, the large second gap reduces the oil flow velocity near the outlet side of the oil pump sprocket cover, thereby reducing the amount of oil mist and the aeration of the oil.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 8 show an embodiment of the present invention. 1 and 2, reference numeral 2 denotes an internal combustion engine, and reference numeral 4 denotes a cylinder block. In the internal combustion engine 2, a cylinder head 6 and a cylinder head cover 8 are fixedly provided on the upper side of the cylinder block 4.

An upper surface of the crankcase 10 is attached to a lower surface of the cylinder block 4. An oil pan 12 is attached to a lower edge portion of the crankcase 10.

A crankshaft 1 is provided between the lower surface of the cylinder block 4 and the upper surface of the crankcase 10.
4 is supported. The crankshaft 14 is arranged from one end surface side (left side in FIG. 2) of the internal combustion engine 2 to the other end surface side (right side in FIG. 2).

As shown in FIGS. 1 and 2, in the internal combustion engine 2, a crank sprocket 16 and an oil pump driving sprocket 18 are sequentially attached to one end (left side in FIG. 2) of the crankshaft 14 from one end. Have been.

A first driving chain 24 wound around a large diameter sprocket 22 provided on the intermediate shaft 20 is provided on the crank sprocket 16, and a small diameter sprocket 26 of the intermediate shaft 20 and the first and second sprockets 26 are provided. First and second sprockets 32, 3 provided on the two camshafts 28, 30
4, the second drive chain 36 is provided by winding.

An oil pump 38 is provided in the oil pan 12, and an oil pump sprocket 40 of the oil pump 38 and the crankshaft 1
An oil pump chain 42, which is a third drive chain, is wound around the oil pump drive sprocket 18 of No. 4 and provided.

Then, the oil pump 3 is driven by the driving force of the crankshaft 14 through the oil pump chain 42.
An oil pump sprocket cover 44 surrounding a part of the oil pump sprocket 40 is provided near the oil pump sprocket 40 in order to prevent the oil in the oil pan 12 from being agitated when the oil pump 8 is driven.

This oil pump sprocket cover 44
A first gap S1 is formed between the oil pump chain 42 and the oil pump sprocket cover 44 on the inlet side into which the oil pump chain 42 enters, and an oil pump on the outlet side from which the oil pump chain 42 exits from the oil pump sprocket cover 44. A second gap S2 is formed between the sprocket cover 44 and the oil pump chain 42, and the first gap S2 is formed to reduce the oil flow rate near the outlet side of the oil pump sprocket cover 44 to reduce the amount of oil mist and the aeration of oil. The second gap S2 is formed to be larger than the gap S1.

More specifically, as shown in FIG. 1, the second gap S2 is formed so as to gradually increase from the lower portion of the oil pump sprocket cover 44 toward the outlet side, and the second gap S2 near the outlet side is formed. The size is formed to be about twice as large as the first gap S1.

Reference numeral 46 denotes an oil strainer disposed in the oil pan 12, and 48 denotes an oil strainer 4
6 is an oil suction pipe communicating with the oil pump 38; 50 is an oil suction port of the oil strainer 34;
Reference numeral 2 denotes a bracket that communicates with the oil pump 38 and the oil pump sprocket cover 44.

Next, the operation will be described.

When the crankshaft 14 rotates, the oil pump drive sprocket 18 fixed to the crankshaft 14 rotates, and the rotational force of the oil pump drive sprocket 18 causes the oil pump drive sprocket 18 to rotate through the oil pump chain 42. The oil pump sprocket 40 is rotated to drive the oil pump 38.

At this time, since the oil pump sprocket cover 44 and the oil pan 12 surround the lower half of the oil pump sprocket 40, oil agitation by the oil pump sprocket 40 and the oil pump chain 42 is prevented. are doing.

The oil pump sprocket cover 4
The oil that has entered the inside 4 is discharged from the second gap S2 on the outlet side of the oil pump sprocket cover 44 by the rotation of the oil pump chain 42 and the oil pump sprocket 40.

At this time, the second gap S2, which is formed so as to be gradually larger from the lower portion of the oil pump sprocket cover 44 toward the outlet side, and is approximately twice as large as the first gap S1, is formed by the oil. In the second gap S2, and the flow velocity of the oil that has been scraped is reduced.

Thus, the flow velocity of the oil scooped up near the outlet by the second gap S2 can be reduced, and the amount of oil mist coming out of the outlet and aeration can be reduced.

Further, since the amount of oil mist can be reduced, the breather chamber in the cylinder head cover can be reduced, which is practically advantageous.

Furthermore, the lubrication performance of the entire internal combustion engine can be improved by reducing oil aeration,
It can contribute to improvement of reliability.

Further, when forming the second gap S2, the second gap S2 is formed to be gradually larger from the lower part of the oil pump sprocket cover 44 toward the outlet side, and is about twice as large as the first gap S1. With this size, the flow rate of the oil can be gradually reduced toward the outlet side, and the amount of oil mist and aeration coming out of the outlet side can be effectively reduced.

It should be noted that the present invention is not limited to the above-described embodiment, and various applications and modifications are possible.

For example, in the embodiment of the present invention, when the second gap is formed, the dimension is about twice as large as the first gap. However, it is also possible to adopt a configuration in which the second gap is further enlarged to surely reduce the oil flow rate.

[0033]

As described above in detail, according to the present invention, the oil pump driving sprocket fixed to the end of the crankshaft and the oil pump sprocket are connected by the driving chain and the rotational force of the crankshaft is used. In an oil pump sprocket cover of an internal combustion engine provided with an oil pump to be driven and an oil pump sprocket cover surrounding the oil pump sprocket of the oil pump, an oil pump sprocket on an inlet side into which a drive chain enters the oil pump sprocket cover. A first gap is formed between the cover and the drive chain, and a second gap is formed between the drive chain and the oil pump sprocket cover on the outlet side where the drive chain exits from the oil pump sprocket cover. The second gap is formed larger than the first gap in order to reduce the oil mist amount and the aeration of the oil by reducing the flow rate of the oil near the outlet side of the cutout cover. The flow rate of the raised oil can be reduced, and the amount of oil mist and aeration flowing out from the outlet side can be reduced. Further, since the amount of oil mist can be reduced, the breather chamber in the cylinder head cover can be reduced, which is practically advantageous. Further, since the aeration of oil can be reduced, the lubrication performance of the entire internal combustion engine can be improved, which can contribute to the improvement of reliability.

[Brief description of the drawings]

FIG. 1 is a partially cutaway schematic front view of an internal combustion engine showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view of an internal combustion engine.

FIG. 3 is a front view of an oil pump sprocket cover.

FIG. 4 is a plan view of an oil pump sprocket cover.

FIG. 5 is a bottom view of the oil pump sprocket cover.

FIG. 6 is a rear view of the oil pump sprocket cover.

FIG. 7 is a cross-sectional view taken along line V〓-V〓 of FIG. 3;

FIG. 8 is a cross-sectional view taken along line V〓-V〓 of FIG. 7;

FIG. 9 is a partially cutaway front view of an internal combustion engine showing a conventional technique of the present invention.

[Explanation of symbols]

 Reference Signs List 2 internal combustion engine 4 cylinder block 6 cylinder head 8 cylinder head cover 10 crankcase 12 oil pan 14 crankshaft 16 crank sprocket 18 oil pump driving sprocket 20 intermediate shaft 24 first driving chain 28 first camshaft 30 second camshaft 36 Second drive chain 38 Oil pump 40 Oil pump sprocket 42 Oil pump chain 44 Oil pump sprocket cover 46 Oil strainer S1 First gap S2 Second gap

Claims (1)

(57) [Claims] An oil pump driven by a rotational force of the crankshaft by connecting an oil pump driving sprocket fixed to an end of the crankshaft with an oil pump sprocket by a driving chain;
In an oil pump sprocket cover of an internal combustion engine provided with an oil pump sprocket cover surrounding the oil pump sprocket of the oil pump, a portion between the oil pump sprocket cover on the inlet side where the driving chain enters the oil pump sprocket cover and the driving chain. And a second gap is formed between the drive chain and the oil pump sprocket cover on the outlet side where the drive chain exits from the inside of the oil pump sprocket cover, and oil near the outlet side of the oil pump sprocket cover is formed. An oil pump sprocket cover for an internal combustion engine, wherein the second gap is formed to be larger than the first gap so as to reduce an oil mist amount and oil aeration by reducing a flow velocity.