Oil seal

Details Oil seal Oil seal

2000-10-30

2002-05-28

Knight, Anthony (Department: 3626)

Seal for a joint or juncture

Seal between relatively movable parts

Circumferential contact seal for other than piston

C277S503000, C277S509000, C123S090370, C123S188600

Reexamination Certificate

active

06394463

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to oil seals and particularly to oil seals for sealing valve stems which are used in combustion engines.
DESCRIPTION OF THE RELATED ART
As shown in
FIG. 4
, an oil seal
52
is mounted on the stem portion of a valve stem
51
of a combustion engine. The oil seal controls the amount of oil between the valve stem
51
and valve stem guide
53
, to prevent the valve stem
51
from initial start-up or dry wear-in (burning-in), to prevent the valve stem guide
53
from normal wear or abrasion, or to prevent a large amount of oil from migrating toward the combustion chamber.
Oil seals
52
of this kind usually have a double lip having a cam or oil chamber side lip
54
for sealing a valve stem
51
and a combustion chamber side lip
55
. The combustion chamber side lip
55
acts to seal oil along the periphery of the reciprocating valve stem
51
. The cam or oil chamber side lip
54
controls the amount of oil which migrates from the cam or oil chamber side toward the combustion chamber side.
With the oil seal
52
having two lips, the variance of the amount of oil that migrates in operation is comparatively small, though there is still some variance in the amount of oil that migrates during operation.
The variance in oil migration or leakage is due to several reasons. As shown in
FIG. 4
, a notch portion
56
is formed on the inner periphery of the combustion chamber side lip
55
, to allow oil to leak from the cam chamber side lip
54
. The notch portion
56
on the inner side of the combustion chamber side
55
allows the valve stem
51
to move toward the notch portion
56
so that the amount of migrating oil is not stable during operation due to the eccentric motion of the valve stem.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an oil seal having a stable oil leak rate during operation by controlling the amount of eccentric movement of the valve stem.
In order to obtain the above mentioned objective, an oil seal of the present invention has a cam chamber side lip and a combustion chamber side lip. A notch is provided on the combustion chamber side lip to permit flow communication of the combustion chamber with the cam or oil chamber. A second combustion chamber side lip is provided next to the combustion chamber side lip and on the side of the combustion chamber. A second notch is provided on the second combustion chamber side lip so that oil can move from the cam or oil chamber to the combustion chamber. The notch on the combustion chamber side lip and the second notch on the second combustion chamber side lip are offset in the circumferential direction.
In the oil seal of the present invention, a second combustion chamber side lip next to the combustion chamber side lip is formed on the side of the combustion chamber side. The second combustion chamber side lip has, like the combustion chamber side lip, a notch or a plurality of notches which permit the combustion chamber to communicate with the cam or oil chamber. The notch on the combustion chamber side lip and the notch portion on the second combustion chamber side lip are offset to one another in the circumferential direction of both lips. Thus, when the valve stem tends to be disposed eccentrically relative to the notch portion of the combustion chamber side lip, the second combustion chamber side lip prevents the valve stem from tending to be eccentric. Additionally, when the valve stem tends to move eccentrically toward the notch on the second combustion chamber side lip, the combustion chamber side lip prevents the valve stem from such eccentric movement.
These and other features of the present invention will become apparent from the description of the embodiments and the drawings.


REFERENCES:
patent: 3601420 (1971-08-01), Binford
patent: 4125265 (1978-11-01), Grzesiak
patent: 4763618 (1988-08-01), Stritzke
patent: 4811704 (1989-03-01), Boehmer et al.
patent: 4909202 (1990-03-01), Binford et al.
patent: 4915069 (1990-04-01), Lafever et al.
patent: 6209504 (2001-04-01), Hegemier et al.
patent: 6244235 (2001-06-01), Hegemier et al.

Affiliated with

Also associated with

Rating

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

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

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2878806