JPH0415969Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a piston that reciprocates within a cylinder bore of an internal combustion engine.

[Conventional technology]

Generally, in pistons for internal combustion engines, an oil ring is provided below the compression ring to scrape off excess oil on the inner wall surface of the cylinder bore. The oil scraped off by the oil ring will collect on the underside of the ring.

Therefore, Japanese Utility Model Application Publication No. 50-39604 as a prior art discloses that an oil ring is formed by carving an oil groove on the outer circumferential surface of the piston that communicates the oil ring groove into which the oil ring is fitted and the piston pin hole. All of the oil accumulated on the lower side is guided into the piston pin hole through the oil groove so that it provides both lubrication for the inside of the piston pin hole and lubrication for the outer peripheral surface of the skirt portion of the piston. I am proposing that.

[Problem that the invention attempts to solve]

However, in this prior art, the oil groove for communicating the oil ring groove and the piston pin hole is opened on the lower inner surface of the oil ring groove. During the upward stroke of the piston, the lower surface of the oil ring comes into close contact with the inner surface of the piston.
This will close the opening of the oil groove to the oil ring groove. Therefore, oil that collects on the upper side of the oil ring during the upward stroke of the piston accumulates in the oil ring groove but cannot escape below the oil ring, which reduces the amount of oil that adheres to the inner wall surface of the cylinder bore. This results in an excessive amount of oil, which in turn causes a large amount of oil to rise into the combustion chamber, increasing oil consumption, while at the same time causing a problem in that oil is insufficiently supplied to the piston pin hole and the outer peripheral surface of the skirt portion of the piston.

In the case where the oil ring groove and the piston pin hole are communicated through the oil groove in this way, the present invention allows all of the oil that collects on the upper side of the oil ring during the upward stroke of the piston to be removed from the oil ring groove. The above-mentioned problem is solved by quickly guiding the piston pin hole.

[Means for solving problems]

For this reason, the present invention provides a piston in which an oil groove is carved in a position below the oil ring groove on the outer peripheral surface of the piston that reciprocates in a cylinder bore so as to extend along the oil ring groove. The oil groove is configured to communicate directly with a piston pin hole that opens on the outer circumferential surface of the piston, while a circular groove on the outer circumferential surface of the piston is formed in a portion between the oil groove and the oil ring groove. The structure is such that oil holes are drilled at a plurality of locations in the circumferential direction so that these two grooves communicate with each other, and are kept at a depth that reaches the bottom surface of the oil ring groove.

[Effect]

In such a configuration, oil that collects on the lower side of the oil ring during the downward stroke of the piston enters the oil groove adjacent to the lower side of the oil ring groove, and flows out into the piston pin hole through this oil groove.

On the other hand, the oil that collects on the upper side of the oil ring during the upward stroke of the piston is caused by the lower surface of the oil ring coming into close contact with the lower inner surface of the oil ring groove during the upward stroke of the piston, and the oil gathering between the upper surface of the oil ring and the upper side of the oil ring groove. Since a gap is formed between the oil and the inner surface, the oil flows into the oil ring groove through this gap.

In this case, by drilling multiple oil holes to communicate between the oil ring groove and the oil groove to a depth that reaches the bottom of the oil ring groove, each oil hole is formed on the bottom surface of the oil ring. Even if the oil hole is in close contact with the lower inner surface of the oil ring groove, it will not be blocked, and the oil that has entered the oil hole will not flow out into the piston, so the piston's upward stroke and downward stroke can be prevented. At this time, all the oil that collects on both the upper and lower sides of the oil ring can be guided to the piston pin hole through the oil groove.

In addition, by configuring the oil groove to communicate directly with the piston pin hole, all of the oil can be quickly guided into the piston pin hole. and,
This makes it possible to reliably lubricate both the outer circumferential surface of the skirt portion of the piston.

〔Example〕

Hereinafter, the present invention will be explained with reference to drawings of embodiments. In the drawings, 1 is a piston, 2 is a piston pin hole, 3 is a ring groove in which a compression ring 4 is fitted, and 5 is an oil ring groove in which an oil ring 6 is fitted. Each is shown.

On the outer peripheral surface of the piston 1, a ring-shaped oil groove 7 is carved along the oil ring groove 5 at a position below the oil ring groove 5, and this oil groove 7 is inserted into the piston pin hole 2. Communicate directly with

Then, in a portion between the oil groove 7 and the oil ring groove, oil holes 8 are drilled at a plurality of locations (six locations in the drawing) in the circumferential direction. In making the oil ring groove 5 and the oil groove 7 communicate with each other in step 8, each oil hole 8 is kept at a depth that reaches the bottom surface 5a of the oil ring groove 5 without penetrating to the inside of the piston 1. and drill it.

Note that 9 is an oil drop groove that communicates the piston pin hole 2 with the lower end of the piston.

The oil hole 8 for communicating the oil ring groove 5 and the oil groove 7 is formed in the oil ring groove 5 as described above.
By setting the depth to reach the bottom surface 5a of
During the upward stroke of the piston 1, the oil ring groove 5
When the lower surface 6a of the inner oil ring 6 is in close contact with the lower inner surface 5b of the oil ring groove 5 as shown in FIG. 3, the oil holes 8 are not blocked by the oil ring 6. Therefore, the oil that collects on the upper surface 6b side of the oil ring 6 can be reliably flowed out to the piston pin hole 2 through the respective oil holes 8 and oil grooves 7. Due to the direct communication, the entire amount of the oil can be guided into the piston pin hole 2 reliably and quickly.

[Effect of idea]

As described above, according to the present invention, in addition to the oil that collects on the lower side of the oil ring, all of the oil that collects on the upper side of the oil ring can quickly flow out into the piston pin hole below the oil ring. Unlike the above-mentioned prior art, it is possible to prevent oil from rising due to the fact that the oil that collects on the upper side of the oil ring does not flow out, and it is possible to significantly reduce oil consumption. This has the effect of reliably preventing insufficient supply of oil to the outer peripheral surface of the part.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a partially cutaway front view of a piston, FIG. 2 is a cross-sectional view taken from FIG. 1, and FIG. 3 is an enlarged view of the main part of FIG. 1. 1... Piston, 2... Piston pin hole, 4...
...Compression ring, 5...Oil ring groove, 6...Oil ring, 7...Oil groove, 8...
...Oil hole, 5a...Bottom surface of oil ring groove.

Claims (1)

[Scope of utility model registration request] A piston in which an oil groove is carved in a position below the oil ring groove on the outer circumferential surface of the piston that reciprocates in a cylinder bore so as to extend along the oil ring groove, the oil groove:
The piston is configured to communicate directly with a piston pin hole that opens on the outer circumferential surface of the piston, while a portion between the oil groove and the oil ring groove has a groove in the circumferential direction of the outer circumferential surface of the piston. A piston for an internal combustion engine, characterized in that oil holes are formed at a plurality of locations so that the grooves communicate with each other at a depth that reaches the bottom surface of the oil ring groove.