Seal for rolling bearing

A seal for a rolling bearing having an outer bearing ring, an inner bearing ring and rolling elements between the outer and inner rings. A seal extends from one of the bearing rings and has axially extending sealing lips engaging a centrifuge plate extending from the other bearing ring. The free end of the centrifuge plate extends to the region of the bearing ring to which it is not affixed, and is angled axially outwardly therefrom.

FIELD OF THE INVENTION 
This invention relates to a seal for a rolling bearing, and more 
particularly to a seal arranged on one of the bearing rings, preferably on 
the outer ring, and having several substantially axially directed, 
outwardly extending seal lips and wherein a centrifuge plate is arranged 
on the other bearing ring, the sealing lips running on the axially inner 
side surface of the centrifuge plate with pretension. 
BACKGROUND OF THE INVENTION 
A seal of this type is disclosed for example in U.S. Pat. No. 2,856,208. In 
this arrangement the centrifuge plate is provided with a cylindrical seat 
mounted on a shoulder of the inner ring, while the radially directed 
annular flange of the centrifuge plate is inclined with respect to the 
outer ring. Since the centrifuge plate is axially inwardly directed toward 
the outer ring, the danger arises that liquids, especially those directed 
from outside the bearing toward the seal, are thrown against the outer 
ring, and penetrate the groove in the outer ring of the bearing through 
the seat of the seal. Otherwise, the centrifuge plate is radially 
relatively short, providing only a minimum centrifugal action, especially 
at minimum rotation speeds of the plate. 
SUMMARY OF THE INVENTION 
The object of the present invention is to so improve a seal of the 
above-described type that the liquids are directed centrifugally away from 
the seal at minimum rotational speeds of the centrifuge plate so that the 
liquids are not thrown against the outer ring. 
This object is solved in accordance with the invention by extending the 
centrifuge plate to the region of the outer ring and angling its free end 
axially outwardly. 
As a result, on the one hand, the diameter of the centrifuge plate is 
increased so that a greater escape force is produced and, on the other 
hand, the centrifuged liquids are held further away from the outer ring. 
According to a further feature of the invention the sealing ring is so 
formed that one of the sealing lips, which extend essentially in the 
axially outward direction, runs on the side surfaces of the angled end of 
the centrifuge plate. In order to increase the sealing action, in 
accordance with a still further feature of the invention, the seal can be 
provided with a projection adjacent the substantially axially directed 
sealing lips, the projection extending radially towards the 
circumferential surface of the other bearing ring and forming an annular 
gap therebetween. Obviously in accordance with a further feature of the 
invention, it is also possible to provide the seal with a sealing lip 
extending radially against the circumferential surface of the other 
bearing ring and engaging the other bearing ring with prestress. 
In order to make the escape of lubricant from the bearing inner space more 
difficult, in accordance with a further feature of the invention, the seal 
is provided with an inclined surface adjacent the free end thereof 
directed toward the other bearing ring, the seal widening from its free 
end so that the inclined surface extends axially inward into the bearing 
inner space. This inclined surface directs lubricant thrown off from the 
bearing inner ring back to the bearing inner space.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIG. 1, the rolling bearing is comprised of an inner ring 
1, an outer ring 2 and a plurality of balls 3 guided by a cage (not shown) 
between the two bearing rings. A seal 4 is provided for sealing the 
bearing, the seal being affixed in a recess 5 in the bore of the outer 
ring 2. The seal has substantially outwardly axially directed, radially 
spaced apart sealing lips 6 and 7 which slidingly engage the axially inner 
side surface 8 of a centrifuge plate 9 arranged, for example, to rotate 
with the inner ring 1 of a shaft on which the inner ring is mounted. Thus, 
as illustrated, for exemplary purposes only, the plate 9 may be affixed to 
the end of inner ring 1. The centrifuge plate 9 extends radially outwardly 
to the area of the outer ring 2 and its radially outer free end 10 is 
inclined axially outwardly of the bearing. The seal 4 has a projection 12 
adjacent the sealing lips 6 and 7, the projection 12 being directed 
radially inward toward the circumferential surface of the inner ring 1 and 
forming an annular gap 11 therewith. The radially outer edge of the 
centrifuge plate 9 is hence preferably substantially in axial alignment 
with the outer ring. 
Furthermore, the seal 4 is provided on its radially inner free end with an 
inclined surface 13 enlarging into the bearing inner space from the free 
end thereof. This inclined surface 13, together with the seal gap 11, 
inhibits any significant quantity of the lubricant from escaping from the 
bearing inner space. Lubricant thrown from the shoulder of the inner ring 
1 is guided back to the inner bearing space by this inclined surface. The 
sealing lips 6 and 7 avoid further escape of the lubricant, so that 
especially the sealing lip 6 prevents foreign materials from outside the 
bearing entering the bearing inner space by force. The centrifuge plate 9 
throws off external liquids directed against the bearing, so that the 
angled end 10 of the centrifuge plate directs the liquid flow away from 
the bearing outer ring. 
In accordance with the embodiment of the invention illustrated in FIG. 2, 
the seal 4 is so formed that the sealing lip 6 sealingly runs on the 
axially inner side surface of the angled end 10 of the centrifuged plate 
9. The side of the seal 4 is likewise so formed at its free end, on the 
side directed toward the bearing inner space, that the lubricant thrown 
from the bearing inner ring is directed axially inwardly back to the 
bearing inner space. 
The two sealing lips 6 and 7 can run with the same prestress force on the 
respective surfaces of the centrifuge plate 9. It is also possible, for 
example, to provide the sealing lip 6 with a lesser prestress force than 
the sealing lip 7. 
While the invention has been disclosed and described with respect to two 
embodiments thereof, it is apparent that variations and modifications may 
be made therein, and it is therefore intended in the following claims to 
cover each such variation and modification as falls within the true spirit 
and scope of the invention.