Piston

Details Piston Piston

2000-02-18

2001-08-28

Ryznic, John E. (Department: 3745)

Expansible chamber devices

Piston

With separable means for pivotally mounting connecting rod...

C092S153000

Reexamination Certificate

active

06279456

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure of a pin bore of a piston for use in an engine.
2. Description of the Related Art
Conventionally, a piston pin for connecting a connecting rod is assembled to a piston used in an engine, and axial ends of the piston pin are supported to pin bores formed coaxially with each other in a pair of piston pin supporting portions of the piston.
In a piston as described above, as described in Japanese Utility Model Unexamined Publication No. Hei.3-42046, a lubricating oil holding portion is provided by forming an axial groove in an inner circumferential surface of a pin bore (for a piston pin) along an axial direction thereof. In addition, a piston pin is normally prevented from being removed by mounting a snap ring which is an annular ring in a snap ring groove formed in an inner circumferential surface of a pin bore. In servicing a vehicle for maintenance, there is a need for the piston pin to be removed, and in order to facilitate the removal thereof, there is formed a snap ring groove relief as a recessed portion for a relevant tool to be inserted thereinto for removing the snap ring.
However, the recessed portion is formed deeper than the axial groove from a need for the tool to be inserted thereinto. This causes a problem that the rigidity of the piston pin supporting portion is deteriorated at the recessed portion.
SUMMARY OF THE INVENTION
With a view to solving the problem, it is an object of the invention to realize the prevention of deterioration in rigidity at the piston pin supporting portion even when the recessed portion is formed for facilitating the removal of the annular clip for preventing the removal of the piston pin.
To attain the above object, there is provided a piston pin bore structure in which a circumferential groove (
14
) is formed in an inner circumferential surface of a pin bore (
2
a
) for assembling therein an annular clip (
13
) for preventing the removal of a piston pin (
10
) inserted through the piston bore (
2
a
). A recessed portion (
15
) formed in the inner circumferential surface of the pin bore (
2
a
) at an outer end thereof so that the annular clip (
13
) can be removed by deforming the annular clip in a radially inward direction coincides in location with an axial groove (
12
) formed in the inner circumferential surface of the pin bore (
2
a
).
According to the above construction, the deterioration in rigidity that would be caused by the provision of the recessed portion can be prevented by forming the recessed portion by making use of a position where the axial groove is formed in such a manner that the recessed portion coincides in location with the axial groove. Moreover, the lubrication inside the pin bore can be improved preferably since a lubricating oil can be led into the axial groove via the recessed portion.


REFERENCES:
patent: 4013057 (1977-03-01), Guenther
patent: 4683808 (1987-08-01), Wacker et al.
patent: 5746169 (1998-05-01), Issler et al.
patent: 3-42046 (1991-04-01), None

Affiliated with

Also associated with

Rating

Piston does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Piston, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Piston will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2443190