Seal for a joint or juncture – Seal between relatively movable parts – Circumferential contact seal for other than piston
Reexamination Certificate
2001-03-19
2003-05-20
Knight, Anthony (Department: 3676)
Seal for a joint or juncture
Seal between relatively movable parts
Circumferential contact seal for other than piston
C277S562000, C277S572000, C277S577000
Reexamination Certificate
active
06565096
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a lip type seal which seals a circumference of a rotary shaft of various sorts of equipments.
PRIOR ART
FIG. 2
shows such a conventional lip type seal. In
FIG. 2
, a case
101
is tightly fitted and fixed to an inner circumferential surface of a housing
1
of the lip type seal through a gasket part
102
a
. A lip member
102
made of elastomer, a resin lip member
103
on the rear side of the lip member
102
and a second resin lip member
104
on the rear side thereof are held to the case
101
. When a sealed space S becomes high in pressure, leakage of a fluid as the seal object is prevented. When the sealed space S becomes vacuum state, the vacuum state is held.
In a lip type seal
100
shown in
FIG. 2
, the lip member
102
on the closest side to the sealed space S is limited by a pressure durable reinforcing ring
105
arranged on the rear surface thereof in deformation due to pressure of the sealed space S. A spiral groove
102
b
producing pumping function in the leakage direction from the sealed space S by the rotation of the rotary shaft
2
is formed on an inner circumference sliding surface.
The resin lip member
103
disposed on the rear side of the lip member
102
made of elastomer is restricted in deformation in an axial direction by a diameter direction part
103
a
in the outer circumference being grasped between the pressure durable reinforcing ring
105
on the front side and the rear surface support plate
106
on the rear side. A spiral groove
103
b
producing a pumping function in the reverse direction to the leakage by the rotation of the rotary shaft
2
is formed on the inner circumference sliding surface.
The second resin lip member
104
arranged on the rear side of the resin lip member
103
is held in the state separated from the resin lip member
103
through an outer circumference spacer part
106
a
of the rear surface support plate
106
and a front surface support plate
107
disposed to abut on the rear end surface of the outer circumference spacer part
106
a
. The diameter direction part
104
a
is grasped between a second rear surface support plate
108
on the rear side of the diameter direction part
104
a
and the front surface support plate
107
. Thereby, deformation in an axial direction is restricted. Also, when the lip type seal
100
is incorporated into the outer circumference of the rotary shaft
2
, the front surface support plate
107
serves as a guide in which the second lip member
104
is bent at the inner circumference side.
According to the aforementioned conventional lip type seal, the rear surface of the second rear surface support plate
108
abuts on the end surface of the housing
1
. Therefore, the second rear surface support plate
108
is not deformed to the side of the atmosphere A. However, in the rear surface support plate
106
, only the outer circumferential part is constrained through the outer circumference space part
106
a
. Therefore, if high pressure acts on the front surface of the resin lip member
103
, the rear surface support plate
106
is subjected to large load in an axial direction through the diameter direction part
103
a
of the resin lip member
103
. As a result, the moment of the inner diameter side becomes large, and as shown in broken line in
FIG. 2
, the rear surface support plate
106
is greatly deformed in bending to the side of the atmosphere A.
Also, the inner diameter of the rear surface plate
106
and that of the second rear surface support plate
108
are formed into the minimum diameter considering the deviation of the rotary shaft
2
in a diameter direction and the maximum amount of the mounting eccentricity, in order that not entering of the resin lip member
103
into the gap G between the outer circumferential surface of the rotary shaft
2
and the rear surface plates
106
,
108
. Therefore, it is preferable that the gap G is made as small as possible. However, the inner diameter edge part
106
b
of the rear surface support plate
106
formed to bend to the side of the sealed space S, corresponding to the bending part of the resin lip member
103
, is slightly displaced to the inner diameter side due to the aforementioned deformation to the side of the atmosphere A. Therefore, if the gap G is made small, the inner diameter edge part
106
b
may come into contact with the outer circumferential surface of the rotary shaft
2
being rotated. On account of such contact, abnormal sound may be produced or large torque may act on a gasket part
102
a
to produce slippage. Hence the lip type seal
100
may be broken.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a lip type seal which prevents bending deformation of a rear surface support plate due to pressure of a sealed space and is excellent in pressure durability.
In a lip type seal according to one embodiment of the present invention, a case is tightly fitted and fixed to an inner circumferential surface of a housing through gasket means. A resin lip member constituted by an inner circumference seal part extending in a bent state from a diameter direction part and its inner circumference to a sealed space side and forming a seal surface between an outer circumferential surface of a rotary shaft and the resin lip member, a rear surface support plate disposed to abut on a rear surface of the diameter direction part of the resin lip member, and a stopper with a rear surface supported to the rising surface side of the housing and the top end coming close to or coming into contact with a rear surface of the inner circumferential part of the rear surface support plate, are provided on the inner circumference of the case.
In addition, “front surface” in the present specification means a surface facing the sealed space side, “rear surface” means a surface facing the opposite side of the sealed space, “front side” means the sealed space side, and “rear side” or “back side” means the opposite side of the sealed space.
REFERENCES:
patent: 2202908 (1940-06-01), Hubbard
patent: 2264148 (1941-11-01), Fisher, Jr. et al.
patent: 2310405 (1943-02-01), Dodge
patent: 3771799 (1973-11-01), Sekulich et al.
patent: 4325591 (1982-04-01), Otto
patent: 4428587 (1984-01-01), Forch
patent: 4623153 (1986-11-01), Nagasawa
patent: 4822059 (1989-04-01), Shimasaki et al.
patent: 4834397 (1989-05-01), Shimasaki et al.
patent: 5083802 (1992-01-01), Shimasaki et al.
patent: 6102409 (2000-08-01), Furuyama et al.
patent: 6123514 (2000-09-01), Kawaguchi et al.
Ikeda Yasuhiro
Imai Takayuki
Yamada Takeshi
Eagle Industry Co. Ltd.
Jacobson & Holman PLLC
Knight Anthony
Patel Vishal
LandOfFree
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