JP3111845B2 - Chain case 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 relates to a chain case structure for an internal combustion engine, and more particularly, to collecting oil scattered in a chain case through an oil guide passage, reducing aeration, and performing lubrication and cooling performance which are basic functions of oil. The present invention relates to a chain case structure of an internal combustion engine that improves blow-by performance while improving the blow-by performance.

[0002]

2. Description of the Related Art An internal combustion engine has a crankshaft that converts a reciprocating motion of a piston into a rotary motion. The driving force, which is the rotational force from the crankshaft, is transmitted to, for example, a camshaft, and the camshaft converts the rotating operation into an opening and closing operation of an intake and exhaust valve.

At this time, a chain is wound around a crank sprocket mounted on the crankshaft and first and second cam sprockets mounted on two first and second camshafts, respectively. It is a driving force transmission path.

A tensioner is provided near the chain, and the tensioner is pressed against the chain by an adjuster to apply an appropriate tension to the chain.

[0005] A chain case structure for the internal combustion engine is disclosed in Japanese Utility Model Publication No. 6-12212. An engine chain case device disclosed in this publication includes a rocker cover provided on an upper portion of a cylinder head of an engine, a head-side chain case provided on a front portion of a cylinder head, and a block side provided on a front portion of a cylinder block. A chain chamber for accommodating the idler sprocket, the first chain, and the second chain is defined through the chain case, respectively, and a joining flange of the head-side chain case to the block-side chain case is located forward of the engine than a joining flange to the rocker cover. In addition to being offset, the block-side chain case has an inclined portion that is continuous from the head-side chain case and that slopes toward the rear of the engine, so that lubricating oil adhering to the rocker cover and chain case can be quickly removed. Flow to oil pan It is, to prevent a siphoning failure from the oil pump.

[0006] Further, there is one disclosed in Japanese Utility Model Laid-Open No. 63-115511. In a chain case device for an engine disclosed in this publication, a chain case for accommodating a chain includes an inner member and an outer member, an oil pump housing is formed at a lower portion of the inner member, and an oil pan side is formed at a lowermost portion of the inner member. A first oil return hole for allowing oil to escape is provided, and an oil damming rib and a second oil return hole for allowing oil blocked by the rib to escape to the oil pan side are provided on the inner member side of the oil pump housing. Provided.

[0007]

By the way, in the conventional chain case structure of an internal combustion engine, as shown in FIG. 4, one side surface of an internal combustion engine (not shown) is covered with a chain case 138.

[0008] Inside the chain case 138, FIG.
As shown in FIG. 7, a plurality of ribs 140 are formed in a horizontal state and an inclined state, respectively, to improve the rigidity, vibration, sound, and the like of the chain case 138.

In addition to the ribs formed inside the chain case, there are also ribs formed outside the chain case.

When the chain enclosed by the chain case 138 is driven, oil is scooped up by a chain and a crank sprocket (not shown), oil leaks from the adjuster 130, and oil is relieved from the relief hole 146 of the adjuster 130. The oil that has been scooped up, leaked, and relieved does not flow down and remains scattered in the chain case.

As a result, if the oil remains scattered in the chain case, aeration increases, lubrication and cooling performance deteriorates, and blow-by performance also deteriorates, which is disadvantageous in practical use. .

[0012]

SUMMARY OF THE INVENTION Accordingly, in order to eliminate the above-mentioned disadvantages, the present invention provides a chain for an internal combustion engine that surrounds a power transmission chain connecting a crankshaft and a camshaft on one side of the internal combustion engine. In the case structure, an oil guide passage for collecting oil scattered into the chain case is formed by two main ribs inside the chain case, and an oil guide passage is provided to be directed to the crankshaft. The height of the rib located in the oil guide passage is smaller than the height of the main rib.

[0013]

According to the invention as described above, when the internal combustion engine is driven, oil scooped up by a chain or the like,
Leakage and relief oil scatter in the chain case, collect oil scattered by the oil guide passage and guide it to the crankshaft side, reduce aeration, improve lubrication and cooling performance, which are basic functions of oil, , Also improves blow-by performance.

[0014]

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 3 show an embodiment of the present invention. In FIG. 2, reference numeral 2 denotes a 4-cycle internal combustion engine mounted on an automobile (not shown), 4 denotes a cylinder head, 6 denotes a cylinder block, and 8 denotes a lower case.

The internal combustion engine 2 includes a cylinder head 4 and
It has a cylinder block 6 mounted on the lower surface of the cylinder head 4 and a lower case 8 mounted on the lower surface of the cylinder block 6.

A crankshaft 10 is pivotally supported by the lower surface of the cylinder block 6 and the lower case 8. On the upper surface of the cylinder head 4, for example, two first and second camshafts 12 and 14 are pivotally supported. Provide.

A crank sprocket 16 is mounted on one end of the crankshaft 10, that is, on the surface side which is one side of the internal combustion engine 2. The second cam sprockets 18 and 20 are respectively mounted, and the power transmission chain 22 is wound around the crank sprocket 16 and the first and second cam sprockets 18 and 20.

The tension side of the chain 22, that is, FIG.
, A first guide portion 24 is disposed near the outside of the right chain 22 and a second guide portion 26 is disposed between the first and second cam sprockets 18 and 20 and near the outside of the chain 22. A tensioner 28 is disposed on the loose side of the chain 22, that is, near the outside of the chain 22 on the left side in FIG. 2, and the tensioner 28 is mounted on the cylinder block 6 so as to be swingable about the lower end.

Between the tension side and the loose side of the chain 22;
That is, the adjuster 30 is disposed inside the chain 22, and the tensioner arm 32 that connects the adjuster 30 and the tensioner 28 is provided.
When one end of the internal combustion engine 2 is fixed to the tensioner 28, a fixing means 34 for fixing from one side of the internal combustion engine 2 is provided.

An adjuster 30 is provided inside the chain 22.
Is arranged such that the load direction, which is the pushing direction of the unillustrated plunger of the adjuster 30, is directed rightward in FIG. 2.

Then, one end of the tensioner arm 32 is fixed to the tensioner 28 from a surface, which is one side of the internal combustion engine 2, by fixing means 34 including fixing bolts. At this time, the other end of the tensioner arm 32 is attached to the adjuster 30 via the pad 36.

Further, the tensioner arm 32 is
As shown in FIG. 7, the adjuster 30 is formed in a curved shape, that is, in a C-shaped cross section, to avoid interference with the adjuster 30 while surrounding a part of the adjuster 30 and to secure high rigidity.

Further, a pad 36 is fixed to the other end of the tensioner arm 32. In order to ensure the transmission of a load between the pad 36 and the plunger tip (not shown) of the adjuster 30, the tensioner arm 32 is used. 3
The contact side of the pad 36 is formed in an arc shape in order to prevent the generation of an extra component when the 2 swings together with the tensioner 28.

One surface of the internal combustion engine 2 is covered with a chain case 38 surrounding the power transmission chain 22.

Then, 2
An oil guide passage 4 for collecting oil scattered in the chain case 38 by the main ribs 40-1 and 40-2 of the book
2, and the oil guide passage 42 is provided so as to be directed to the crankshaft 10. The height of the rib 44 located in the oil guide passage 42 between the two main ribs 40-1 and 40-2 is set as described above. Main rib 40-1, 40
-2 is set to be smaller than the height.

More specifically, as shown in FIG. 1, the crankshaft 10 obliquely lowers in an arc while shifting from the outer edge portion to the center portion at a height position substantially coincident with the upper portion of the cylinder block 6 of the chain case 38. A pair of symmetrical main ribs 40-1 and 40-2 directed to the portion are formed, and an oil guide passage 42 is formed between the main ribs 40-1 and 40-2.

Also, located in the oil guide passage 42,
For example, three first to third ribs 44-1 and 44 in a horizontal state
3, the height h of the main ribs 40-1 and 40-2 is smaller than the height H of the main ribs 40-1 and 40-2 to secure the oil guide passage 42.

Reference numeral 46 denotes a relief hole of the adjuster 30.

Next, the operation will be described.

When the internal combustion engine 2 is driven, the driving force from the crankshaft 10 is applied to the crank sprocket 1
6, the power transmission chain 22, the first and second cam sprockets 18, 20, and the first and second cam shafts 12, 14 are sequentially transmitted.

When the chain 22 is driven, oil is scraped up by the chain 22 and the crank sprocket 16, and oil leaks from the adjuster 30, so that the oil is relieved from the relief hole 46 of the adjuster 30. Raised oil, leaked oil, and relieved oil scatter in the chain case 38.

At this time, the oil guide passage 42 is provided inside the chain case 38 by the main ribs 40-1 and 40-2.
The oil scattered by the oil guide passage 42 is collected and guided to the crankshaft 10 side.

Thus, the oil scattered in the chain case 38 by the oil guide passage 42 can be collected reliably and easily, and aeration is reduced.
Lubrication and cooling performance, which are basic functions of oil, can be improved, and blow-by performance can also be improved, which is practically advantageous.

By directing the oil guide passage 42 toward the crankshaft 10, the oil collected by the oil guide passage 42 is
The lubrication of the crank sprocket 16 and the chain 22 can be performed, and the lubrication performance can be improved.

Further, the main ribs 40-1 and 40-2
The three first to third ribs 44-1 and 44- located in between
By making the height of 2, 44-3 smaller than the height of the main ribs 40-1, 40-2, the oil guide passage 42 can be reliably formed inside the chain case 38.

[0037]

As described above in detail, according to the present invention, in a chain case structure of an internal combustion engine that surrounds a power transmission chain that connects a crankshaft and a camshaft on one side of the internal combustion engine, An oil guide passage for collecting oil scattered into the chain case is formed by two main ribs on the inside, and the oil guide passage is provided so as to be directed to the crankshaft.
Since the height of the ribs located in the oil guide passage between the main ribs is made smaller than the height of the main ribs, the oil scattered into the chain case by the oil guide passage can be collected reliably and easily. Thus, aeration is reduced, lubrication and cooling performance, which are basic functions of oil, can be improved, and blow-by performance can be improved, which is practically advantageous. Further, by directing the oil guide passage toward the crankshaft, the oil collected by the oil guide passage is guided to the crankshaft portion, and the lubricated portion can be lubricated, and the lubrication performance can be improved. Furthermore, by making the height of the ribs located between the main ribs smaller than the height of the main ribs, the oil guide passage can be reliably formed inside the chain case.

[Brief description of the drawings]

FIG. 1 is a rear view of a chain case showing an embodiment of the present invention.

FIG. 2 is a front view of the internal combustion engine before a chain case is mounted.

FIG. 3 is a plan view of a chain case.

FIG. 4 is a rear view of a chain case showing a conventional technique of the present invention.

[Description of Signs] 2 Internal combustion engine 4 Cylinder head 6 Cylinder block 8 Lower case 10 Crankshaft 12 Second camshaft 14 Second camshaft 16 Crank sprocket 18 First cam sprocket 20 Second cam sprocket 22 Power transmission chain 24 First Guide part 26 Second guide part 28 Tensioner 30 Adjuster 32 Tensioner arm 34 Fixing means 36 Pad 38 Chain case 40-1, 40-2 Main rib 42 Oil guide passage 44 Rib 46 Relief hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02B 67/06 F01M 1/06 F01M 9/06 F02F 7/00 F16M 1/026

Claims (1)

(57) [Claims] 1. A chain case structure for an internal combustion engine that surrounds a power transmission chain that connects a crankshaft and a camshaft on one side of the internal combustion engine. An oil guide passage for collecting the scattered oil is formed, and the oil guide passage is provided so as to be directed to the crankshaft. The height of the rib located in the oil guide passage between the two main ribs is higher than the height of the main rib. A chain case structure for an internal combustion engine, characterized in that the structure is also small.