Oil passage arrangement in a piston

Details Oil passage arrangement in a piston Oil passage arrangement in a piston

2000-02-18

2001-12-04

Ryznic, John E. (Department: 3745)

Expansible chamber devices

With lubricating means

Piston has lubricant retaining or conducting means

Reexamination Certificate

active

06324961

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an oil passage arrangement in a piston for use in an engine.
2. Description of the Related Art
Conventionally, a piston pin is assembled to a piston for use in an engine for connecting a connecting rod to the piston. With a view to lubricating and cooling the piston pin, an oil passage is provided which extends from an oil ring groove formed in the piston to the interior of the piston so that a lubricating oil clinging to the inner wall of a cylinder is supplied to the piston pin. A piston provided with an oil passage as described above is represented by one disclosed in Japanese Utility Model Examined Publication No. Sho. 61-35716.
In the oil passage arrangement of the piston disclosed in the cited Publication, however, since there is provided a single oil passage extending from the oil ring groove formed in the piston to an uppermost end portion of a piston-pin hole supporting therein the piston pin, although a certain cooling effect can be expected, this means that the oil passage is formed in the piston pin supporting part which is adapted to carry a great magnitude of explosion load, and this may cause a risk of the rigidity of the piston being deteriorated. Also, the distance between the piston head part and the piston-pin hole becomes long and this causes a problem of the piston being made larger, and such a construction is not suitable for a piston head in particular for a high speed engine.
SUMMARY OF THE INVENTION
To solve these problems, it is an object to provide an oil passage arrangement which realizes improvements in cooling performance of a piston pin, as well as in reduction in size and weight of a piston.
To attain the above object, according to the present invention, there is provided an oil passage arrangement in a piston (
1
) with an oil passage (
12
) extending from an oil ring groove (
5
) formed in an outer circumferential surface of the piston (
1
) to a piston inner side surface (
2
b
) of a piston-pin supporting part (
2
) through which a piston-pin hole (
2
a
) is formed for insertion of a piston pin (
10
) therethrough at a portion situated on a side of an upper end portion of the piston-pin hole (
2
a
) through the interior of the piston pin supporting part (
2
), so that a lubricating oil collected in the oil ring groove (
5
) is supplied to the piston pin (
10
).
According to this construction, since the lubricating oil is supplied to the upper end portion of the piston pin, it is possible to improve the cooling effect on the piston pin, and in addition, since the oil passage is made open to the interior of the piston at a position other than a position directly above the upper end portion of the piston-pin hole, there is no risk of a reduction in thickness at the piston pin supporting part above the piston-pin hole and hence no risk of reduction in rigidity thereat, thereby making it possible to make the piston compact.
Further, the oil path (
12
) may be formed at portions situated on sides of the upper end portion of the piston-pin hole (
2
a
), and the respective oil passages are provided diagonally relative to an axis of the piston-pin hole (
2
a
) in such a manner as to be directed toward a central part of the piston (
1
), and this facilitates the formation of the oil passages. Moreover, the construction allows to a sufficient amount of lubricating oil to be supplied toward the central part of the interior of the piston, and this allows the lubricating oil to be supplied to the upper end portion of the piston pin which needs lubricating and cooling without necessity of making the oil passages to be opened directly above the piston pin in a preferred fashion.


REFERENCES:
patent: 1605040 (1926-11-01), Kreis
patent: 1953109 (1934-04-01), Heron
patent: 2108194 (1938-02-01), Church
patent: 2695824 (1954-11-01), Klingel, Jr.
patent: 4794848 (1989-01-01), Melchoir
patent: 6152016 (2000-11-01), Bahr et al.
patent: 6205908 (2001-03-01), Kumai et al.
patent: 61-35716 (1986-10-01), None

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