GB2252139A

GB2252139A - Double lipped seal

Info

Publication number: GB2252139A
Application number: GB9201544A
Authority: GB
Inventors: Peter Dreschmann; Wilheim Walter
Original assignee: FAG Kugelfischer Georg Schaefer KGaA; Kugelfischer Georg Schaefer and Co
Current assignee: IHO Holding GmbH and Co KG
Priority date: 1991-01-25
Filing date: 1992-01-24
Publication date: 1992-07-29
Also published as: DE4102130A1; FR2672098A1; FR2672098B3; GB9201544D0

Abstract

Various seal conditions (sliding seal, labyrinth seal or a mix of these systems) are simply achieved for a double-lipped seal, in that with a given double-lipped seal, the space between the lips 6, 5 and associated radial 10 and axial 9 annular faces respectively may be greater than zero, equal to zero (for abutment) or less than zero (in which the lip or lips are resiliently urged against their associated faces), with the possibility of mixed systems. <IMAGE>

Description

a 2252139 - 1 Double-lipped seal The present invention relates to a

double-lipped seal, especially but not exclusively for a roller bearing.

Double-lipped seals have been prepared and used for decades. In order to achieve specific sealing effects a plurality of differently designed seals are used, which stand opposite to seal parts of different designs. Thus for example in DE-U-19 46 540, DE-U-72 30 879, DE-U-19 40 357 and DE-A-35 19 027, such seals are shown in which seals of different designs rest with their two lips each in sliding manner on counter-faces, with overlap. DE-U-84 757 and DE-U-84 37 101 show seals in which one lip is in abutment while the other lip stands with gap opposite to a counter-face. DE-A-18 01 854 and DE-B-28 03 093 show seals in which the sealing effects vary during operation.

US-A-3,414,275 on the other hand shows a double-lipped seal which stands with a gap opposite to all counter- faces.

The practice carried out hitherto and discussed above necessitates a great expenditure both on the design of the seals themselves and also on the formation of the counter-faces in each case.

An aim of the present invention is to provide a seal with the aid of which, by simple means, the varied seal conditions (sliding seal, labyrinth seal or mixed systems thereof) can be achieved using a double-lipped 1 2 - seal design.

Accordingly the present invention is directed to double-lipped seal, especially but not exclusively for roller bearing, in which one of the lips is juxtaposed to a generally radially extending annular face of an annular groove, and the other of the lips is juxtaposed to a generally axially extending annular face of the annular groove.

Preferably one or both of the lips are in contact with their associated annular faces.

Advantageously, one or both of the lips are resiliently urged against their associated annular faces.

In a preferred embodiment the radial and axial annular faces are provided by a groove at an edge of a race ring of a roller bearing.

Desirably, the annular faces are arranged slightly obliquely relative to the true radial and axial orientations.

Preferably, one or both of the sealing lips are provided with at least one continuous groove.

In another of its aspects, the present invention provides a double-lipped seal, especially but not exclusively for a roller bearing, in which one lip stands opposite to an approximately radial annular face and the other to an approximately axial annular face of an annular groove, in which according to the desired type of seal, with equal unchanged seal or annular groove the spacing of k the radial and axial annular faces f rom the seal lips is greater than 0, equal to 0 or less than 0, including mixed systems thereof, the annular faces and/or the sealing lips, as the case may be, being positioned according to the desired type of seal.

The present invention extends to a method of making different forms of a double-lipped seal, especially but not exclusively for a roller bearing, in which seal one of the lips is juxtaposed to a generally radially extending annular face of an annular groove of the bearing, and the other of the lips is juxtaposed to a generally axially extending annular face of the annular groove, the method comprising the step of varying the position of the or both faces whilst retaining the same position for and dimensions of the lip-bearing part, or varying the position or dimensions of the latter whilst retaining the same positions of the faces.

Thus with such a seal, the double-lip part may be made identical, and the juxtaposed surfaces may be re- positioned, or alternatively the annular groove may be made identical, and the part which provides the double-lip may be altered to obtain a different form of seal. If for example as a result of the modifications the distance between the axial face and the juxtaposed sealing lip is made larger, a labyrinth relationship may result. If on the other hand the spacing is made less than zero (that is to say so that a lip is resiliently urged against its t juxtaposed surface, a sliding seal may be obtained. In the case of a mixed system one sealing lip is in abutment while the other is spaced from its counter-face. In order to achieve this in each case, slight displacements of the counter-face or the sealing lips are effected, which can be achieved, in the production of the faces and/or lips, by a simple modified dimensioning. The former can be produced for example by the application of a different shaping tool or a different profiled grinding wheel, or by a modified application of the same shaping tool or profiled grinding wheel.

In the case of roller bearings, where the installation space is limited, it is sensible to arrange the radial and axial annular faces on a groove at the edge of one of the race rings. Here the two annular faces can be produced at the same time in one action. The arrangement of these annular faces in a slightly obliquely inclined orientation has the advantage that when the rings are rotating, a useful action is produced or promoted.

Since for example owing to temperature variations in the bearing, with sealing lips in abutment, an undesired excess or negative pressure might occur, one or both sealing lips can be provided with at least one groove in the region of their abutment face. Thus a pressure equalisation is possible, whereby for example an unacceptably high pressure upon and wear of the sealing lips is avoided.

1 - An example of a two-lipped seal made in accordance with the present invention is shown in the accompanying drawings, in which:

Figure 1 shows a cross-section through a ball5 bearing with such a seal; Figure 2 shows a part of Figure 1 drawn on a larger scale with a modified annular groove arrangement; Figures 3 and 4 show respective modifications of the groove arrangement shown in Figure 2; Figure 5 shows, on a larger scale, details of possible modifications of the annular groove arrangement on the inner race ring, of the ball-bearing shown in Figure 1; and Figure 6 shows a similar detail with modified sealing lips.

In Figure 1, a specific seal 2 is secured in an outer race ring 1 of a ball-bearing. The seal 2 protects the inner space of the bearing, with balls 3 and a cage 4, against external influences. Two sealing lips 5 and 6 of this seal 2 lie in an annular groove 7 at an edge of the inner race ring 8, namely in such a manner that the lip 5 is juxtaposed to and abuts a slightly obliquely inclined generally axially extending face 9 and the lip 6 is likewise obliquely inclined face 10. The inclinations are with respect to the true axial and radial orientations.

juxtaposed to and abuts a generally radially extending one or both lips 5 and 6 may not only abut their associated faces 9 and 10, but they may also be resiliently urged against those faces.

In practice the arrangement that is desired is not always this double abutment of the sealing lips, but occasionally also guide systems such as those shown in Figures 2, 3 and 4. Thus the same seal 2 in Figure 2 lies with neither of its sealing lips 5 and 6 abutting counterfaces 9,1 and 101. In Figure 3 the sealing lip 5 comes into contact with the face 9, while the lip 6 stands adjacent to but spaced from the face 101, whereby a mixed system results. In Figure 4 the lip 6 lies against the face 10, but the lip 5 is not in contact with the face 91.

The different modifications of the seal arrangements 15 can thus be achieved by only slight modification of the groove faces or the lipbearing part. In fact, as shown in Figures 5 and 6 in an assembly on the inner race ring 8, the modification can be achieved by varying the positions of one or both of the faces 9 and 10 to the set- back position 91 and 100, or by varying the positions of one or both of the sealing lips 13, and 14 of the seal 12 to the forward positions 13f and 141, whilst retaining the positions of the faces 9 and 10 of the annular groove 15.

So that a pressure equalisation can take place in both directions, the sealing lip 6 possesses a groove 11. Thus in the case of an abutting sealing lip 6 and a non-abutting sealing lip 5, as represented in Figure 4, this desired arrangement is effected in a simple manner.

Thus, various seal conditions (sliding seal, labyrinth seal or a mix of these systems) are simply achieved for a double-lipped seal, in that with given double-lipped seal 2, the interval of space between the lips and associated radial and axial annular faces respectively may be greater than zero, equal to zero (for abutment) or less than zero (in which the lip or lips are resiliently urged against their associated faces), with 10 the possibility of mixed systems.

claims 1. A double-lipped seal, especially but not exclusively for a roller bearing, in which one of the lips is juxtaposed to a generally radially extending annular face of an annular groove, and the other of the lips is juxtaposed to a generally axially extending annular face of the annular groove.

2. A seal according to claim 1, in which one or both of 10 the lips are in contact with their associated annular faces.

3. A seal according to claim 2, in which one or both of the lips are resiliently urged against their associated annular faces.

4. A seal according to any preceding claim, in which the radial and axial annular faces are provided by a groove at an edge of a race ring of a roller bearing.

5. A seal according to any preceding claim, in which the annular faces are arranged slightly obliquely relative to the true radial and axial orientations.

6. A seal according to any preceding claim, in which one or both of the sealing lips is provided with at least one continuous groove.

7. A double-lipped seal substantially as described 25 herein with reference to and as shown in any one of the accompanying Figures 1 to 6.

8. A double-lipped seal, especially but not exclusively for a roller bearing, in which one lip stands opposite to an approximately radial annular f ace and the other to an approximately axial annular face of an annular groove, in which according to the desired type of seal, with equal unchanged seal or annular groove the spacing of the radial and axial annular faces from the seal lips is greater than 0, equal to 0 or less than 0, including mixed systems thereof, the annular faces and/or the sealing lips, as the case may be, being positioned according to the desired type of seal.

9. A method of making different forms of a double-lipped seal, especially but not exclusively for a-roller bearing, in which seal one of the lips is juxtaposed to a generally radially extending annular face of an annular groove, and the other of the lips is juxtaposed to a generally axially extending annular face of the annular groove, the method comprising the step of varying the position of the or both faces whilst retaining the same position for and dimensions of the lip-bearing part, or varying the position or dimensions of the latter whilst retaining the same positions of the faces.