JPS6339362Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a lubricating oil passage structure for returning oil from an engine cam chamber to an oil pan. This article relates to a lubricating oil passage structure suitable for this type of engine.

(Prior Art) Generally, there are two types of lubrication methods for intake and exhaust valve cams and tappets: a method in which oil is splashed, and an oil bath method in which oil is stored in a cam chamber. When comparing the two, the oil bath method has the advantage of increasing the durability of the tapepet. However, on the other hand, with the splash method, the oil splashed on the cam etc. can fall directly downwards, whereas with the oil bath method, a dedicated oil passage must be provided to return the oil in the cam chamber to the oil pan. However, there is a problem in that the structure of the return oil path becomes complicated.

More specifically, one end of the engine is provided with a gear and a gear case for driving a camshaft and auxiliary machinery, and the other end is provided with a flywheel and a flywheel housing. Therefore, it is convenient to place the lubricating oil pump on the gear case side of the engine. Therefore, in order to simplify the structure, the supply oil passage for supplying lubricating oil to the cam chamber is also placed on the gear case side. It's convenient. As a result, in order to obtain such advantages, it is necessary to provide the return oil passage from the cam chamber on the flywheel side.

The return oil passage can be formed by forming an oil passage hole inside the cylinder block that extends to the oil pan, or by arranging an oil passage pipe outside the cylinder block. Since it takes time and money to process, it is actually necessary to form a return oil passage with a pipe.

However, in the high-cam type engine, the camshaft and cam chamber are located roughly in the middle between the crankshaft and the cylinder head, and more specifically, the camshaft and cam chamber are located near the flywheel housing and closer to the cylinder head than the flywheel housing. The cam room is located in.

Therefore, when arranging the external pipe for the return oil passage, the flywheel housing becomes an obstacle, and in order to avoid this, it is necessary to adopt a pipe with a complicated structure. Of course, the external pipe can be separated from the flywheel housing and placed on the side of the engine, but generally, auxiliary equipment such as an oil filter and an oil cooler are placed on the side of the engine. Therefore, if you place the pipe on the side of the engine, the auxiliary equipment will get in the way.
In order to avoid this, it is necessary to adopt a pipe with a complicated structure.

In short, in oil bath type engines, it is generally desirable to provide a return oil passage for the cam chamber on the flywheel side, but in high cam type engines, the cam chamber is located in an area not covered by the flywheel housing and in the vicinity. Therefore, in the conventional structure, there is a problem that the structure of the return oil path becomes complicated.

(Purpose of the invention) In order to solve the above-mentioned problems, the present invention attempts to provide a lubricating oil passage structure using a flywheel housing.

(Structure of the invention) The present invention provides the above-mentioned high cam type and oil bath type engine, in which a cylindrical peripheral wall surrounding the outer periphery of the flywheel is provided in the flywheel housing.
An annular end wall located between the flywheel and the cylinder block end wall, and a flange protruding from the annular end wall toward the cylinder head side are provided, and the flange and the annular end wall are connected to the cylinder block end wall. An opening communicating with the cam chamber is formed in the end wall of the cylinder block at a position covered by the flange, and an opening communicating with the cam chamber is formed between the flange and the end wall of the cylinder block and between the annular end wall and the end wall of the cylinder block. A series of return oil passages are formed between the opening and the oil pan, and the opening is connected to the oil pan below.

(Example) In FIG. 1, which is a schematic vertical cross-sectional view, a camshaft 3 for driving intake and exhaust valves is provided inside a cylinder block 1 of a multi-cylinder engine in parallel with the center line O-O of a crankshaft 2. be. The illustrated engine is of a high cam type, and the camshaft 3 is provided at a high position approximately on the side of the piston 4. The camshaft 3 includes intake valve and exhaust valve cams 5, 5 for each cylinder.
A tapepet 6 is seated from above. Each tapepet 6 is seated with a lower end of a push rod 7 extending vertically. An upper end (not shown) of the push rod 7 is connected to an intake valve and an exhaust valve via a rocker arm.

Each camshaft 3 has one set of cams 5, 5 (for each cylinder).
It is supported on both sides by the boss 8 of the cylinder block 1 via a bush 9. A cam chamber 10 is formed inside the cylinder block 1 between two adjacent bosses 8, 8.
is provided with an oil hole (not shown) that connects the cam chambers 10, 10 on both sides. Oil is stored in the cam chamber 10, and a portion of the cam 5 is immersed in the oil. Although not shown, the cylinder block 1 is provided with a supply oil passage for supplying oil to the cam chamber 10.

An oil pan 13 is bolted to the lower end of the end wall 12 and side wall (wall parallel to the crankshaft center line OO) of the cylinder block 1. crankshaft 2
In Fig. 1, the right end is the boss 1 provided at the bottom of the end wall 12.
5 via a bearing metal 16. A metal cap 17 is bolted to the lower surface of the boss 15, and the lower half of the bearing metal 16 is supported by the metal cap 17. The crankshaft 2 protrudes outward from the end wall 12, and a flywheel 20 is fitted into the protruding end thereof and fixed by bolts 21 and positioning pins 22.

The flywheel 20 is covered by a flywheel housing 23 from the outer peripheral side and the end wall 12 side. The annular end wall 25 of the housing 23 is connected to the end wall 12
bolted to the outside of the A seal 26 is interposed between the inner periphery of the end wall 25 and the tip of the crankshaft 2.

As shown in FIG. 2, which is a partial view of FIG.
As shown in FIG. 1, the flange 28 is continuous with the upper part of the end wall 25, and the flange edge 28 is in close contact with the outer surface of the end wall 12. A recess for forming an oil passage 30 is provided on the surface of the flange 28 on the end wall 12 side. The oil passage 30 is surrounded by the edge 29 and extends downward. A gap 32 is formed between the upper part of the housing end wall 25 and the outer surface boss 31 of the block end wall 12 facing thereto, and a gap 32 is formed between the end walls 12 and 25.
An oil passage 33 is formed by the above. The oil passage 33 extends from the lower end of the oil passage 30 to around the boss 15.

The cylinder block end wall 12 is provided with an opening 35 communicating with the oil passage 30. As shown in FIG. 3, which is an enlarged partial cross-sectional view of FIG.
Connected to 0.

(Operation) When the engine is in operation, the camshaft 3 is driven by the crankshaft 2 via a gear mechanism (not shown) on the opposite side of the flywheel 20. As a result, the cam 5 drives the push rod 7 via the tappet 6, and the push rod 7 drives the intake valve and the exhaust valve via the rocker arm.

During this operation, the cam 5 and tappet 6 are lubricated by the oil in the cam chamber 10. This oil is supplied to the cam chamber 10 from the supply oil passage, lubricates the cam 5 and the tappet 6 within the cam chamber 10, and then is discharged from the opening 35 to the oil passage 30. The oil flowing into the oil passage 30 flows down around the oil passage 33 and the boss 15 and returns to the inside of the oil pan 13.

(Effect of the invention) As explained above, according to the invention, the flywheel housing 23 and the cylinder block end wall 1
2, and this oil passage 30 forms a lubricant return oil passage that connects the cam chamber 10 and the oil pan 13. Even though the return oil passage is provided on the flywheel 20 side, This eliminates the need for oil passage pipes and simplifies the structure.
In other words, the return oil passage can be provided on the flywheel 20 side without any problem. Also, oil is on the end wall 12.
Since the returned oil does not collide with the crank arm 37 or the like, wasteful agitation of the oil can be prevented, and oil up (inflow into the combustion chamber 38) can be prevented.

Furthermore, the flywheel 20 is provided with a flange 28, and the oil passage 30 in the flange 28 is connected to the outlet opening 35 of the cam chamber 10, so that even when the cam chamber 10 is located at a high position as in a high cam type engine, The oil passage 30 can be connected to the opening 35 without any problem. Moreover, by providing the flange 28 on the flywheel 20, the attachment strength of the flywheel 20 to the end wall 12 can be stabilized.

[Brief explanation of the drawing]

1 is a schematic vertical sectional view of the embodiment, FIG. 2 is a partial view taken in the direction of the - arrow in FIG. 1, and FIG. 3 is an enlarged partial view of the - sectional view in FIG. 1. 1...Cylinder block, 2...Crankshaft,
10...Cam chamber, 12...Cylinder block end wall, 13...Oil pan, 20...Flywheel, 23...Flywheel housing, 25...
...Annular end wall, 27...Peripheral wall, 28...Flange,
30, 33...oil passage, 35...opening.

Claims (1)

[Scope of utility model registration request] A cam chamber with an oil reservoir structure is provided inside the cylinder block at an approximately intermediate position between the crankshaft and the cylinder head, and a flywheel housing is disposed adjacent to one end wall of the cylinder block. , a cylindrical peripheral wall surrounding the outer periphery of the flywheel, an annular end wall located between the flywheel and the cylinder block end wall, and a flange protruding from the annular end wall toward the cylinder head side; and the annular end wall are fixed tightly to the cylinder block end wall, and at a position covered by the flange,
An opening communicating with the cam chamber is formed in the end wall of the cylinder block, and a series of return oil passages are formed between the flange and the end wall of the cylinder block and between the annular end wall and the end wall of the cylinder block. A lubricating oil passage structure for an engine, characterized in that the opening is connected to a lower oil pan by a return oil passage.