Bearing seal

Abstract: A bearing seal (10) has a casing 11 with a dynamic sealing element (18) such as an EHD at an inner edge. At the outer edge of the casing (11) a static sealing element (14) is provided on an axially extending flange (13). The static sealing element (14) includes opposing outwardly projecting sealing lips (23) which are capable of deflection and which have an outer diameter greater than the diameter of the bearing housing bore. The bearing seal (10) seals the inner and outer race rings of a bearing dynamically and also the outer race ring with the bearing housing statically and positively.

Description: The present invention relates to a bearing seal and particularly to a bearing seal for use in sealing between the inner and outer races of a bearing having for example tapered, cylindrical or ball rolling elements. US-A-3519316 discloses an annular bearing seal comprising a substantially rigid radially extending sealing structure having at an inner edge region an annular dynamic sealing element and having at an outer edge region an annular static sealing element which is mounted on an axially extending flange on the sealing structure and which extends axially away from the sealing structure, the static sealing element including at least one deformable projection radially outwardly of the static sealing element. According to the present invention there is provided a groove in the static sealing element radially inwards of the or each deformable projection and the static sealing element is mounted to extend on both radially inner and outer surfaces of the axially extending flange. With the present invention the bearing seal is arranged to provide a dynamic seal with respect to the inner race of a bearing and in addition a static seal between the outer race of the bearing and a housing. In this way two separate sealing functions are met in a single component. Moreover, with the deformable projection provided on the static sealing element a positive seal can be achieved between the outer race and the housing even where the bearing is clamped in position within the housing with the outer race of the bearing otherwise a loose fitting within the housing. In an alternative aspect the present invention provides a bearing having an inner race ring, an outer race ring and rolling elements therebetween in combination with a bearing seal as described above, the outer race ring of the bearing including a recess open to an axial outer face of the race ring for receiving the static sealing element of the bearing seal. Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a sectional view through a tapered roller bearing having a bearing seal in accordance with the present invention; Figure 2 is an enlarged sectional view of the bearing seal of Figure 1; Figure 3 is an enlarged sectional view of part of an alternative roller bearing in accordance with the present invention; and Figure 4 is an enlarged sectional view of part of a further alternative roller bearing in accordance with the present invention. The integral bearing seal 10 shown in Figure 1 functions to form a seal between the static 4 and rotating 3 elements of a bearing 2 and also to form a seal between the static element or outer ring 4 of the bearing 2 and the housing 5 in which the bearing is mounted. Thus, the bearing seal 10 being a single component performs two separate sealing functions. The bearing seal 10 has a substantially rigid casing 11, for example made of steel, which is generally planar and ring shaped to enable the bearing seal to be located about a rotating shaft (not shown). On the axially outwardly facing surface of the casing 11 there is a coating 12 of a rubber or other resilient material. The coating 12, which may include a circular ridge 12' as shown, provides a sealing surface so that the bearing seal 10 can form a seal with the surface of a clamping member which is used to hold the bearing in position within the housing when the bearing is loose fitting. For certain types of steel suitable for used in the manufacture of the casing 11, the coating 12 may be dispensed with. At the radial outer edge of the casing 11 an axially inwardly extending flange 13 is provided which is enveloped in a static sealing member 14. The static sealing member 14 may be made of a rubber material or an alternative resilient material having the characteristics of acting as a barrier to the escape of grease or the ingress of water/emulsion and other contaminants. At opposed axial edges of the static sealing member 14 deformable lips 23 are provided each of which extend radially outwardly beyond the outer surface of the static sealing member 14. Thus, the outer radial diameter of the lips 23 is greater than the outer diameter of the static sealing member 14. The outer diameter of the lips 23 is also greater than the diameter of the housing bore 5. The static sealing member 14 also includes respective grooves 22 adjacent the lips 23. The grooves 22 preferably are provided radially inwardly of the lips 23, as shown in Figure 2, so as to assist in the deformation or deflection of the lips 23 radially inwardly. Hence, when in use, insertion of the bearing with the bearing seal in place within the housing bore causes deformation of the lips 23 which in turn ensures a positive seal between the outer race ring 4 and the housing 5. In this way a secure seal can be formed between the otherwise loose fitting of the outer race ring 4 in the housing 5. A recess 6 in the static element or outer ring 4 is open to the axial outer face of the ring 4. This enables the bearing seal 10 and in particular the static sealing member 14 to be more easily positioned on the axial outer face of the bearing 2. When in use the bearing seal 10 is mounted on the face of the bearing 2 with the static sealing member 14 located in the recess 6. The bearing 2 is then clamped in position in the bearing housing with the coating 12 forming a seal with the shoulder of the clamp and is mounted on a shaft (not shown). So that the bearing seal 10 does not become inadvertently detached from the bearing 2 whilst outside of the housing, the minimum inner diameter of the static sealing member 14 is preferably substantially equal to the diameter of the recess so that the static sealing member 14 fits tightly within the recess without making the bearing seal difficult to remove from the bearing when necessary. At the radial inner edge of the casing 11 a lip seal member 18 is provided similarly made of rubber, for example, or an alternative resilient sealing material. The lip seal member 18 has a lip seal element 16 and additionally an elastohydrodynamic (EHD) lip 17 which is described in detail in EP0304160 the contents of which is incorporated herein by reference. The lip seal member 18 is designed to enable the bearing seal 10 to form a seal with the outer surface of the rotating element or inner race ring 3 of the bearing. Axial holes 19 (one is shown) are provided in the casing 11 to enable venting, if needed. The holes 19 are covered by the coating 12 but can be opened , if desired, by cutting through the coating. With reference to Figure 3, to assist the positioning of the bearing seal 10 on the end of the bearing and in particular the location of the static sealing member 14 within the recess 6, the outer ring 4 may include, within the recess 6, a circular ridge 25 which engages with an inner shoulder 26 on the static sealing member 14. The ridge 25 also assists in holding the bearing seal 10 on the end of the bearing when the bearing is removed from the housing 5. Alternatively, with reference to Figure 4, the recess 6 may include a circular sealing groove 27 within which is located an o-ring or other sealing spring 28 which similarly abuts against the inner shoulder 26 on the static sealing element. It will be seem from the above that the bearing seal 10 replaces what conventionally has been two separate seals; i.e. a dynamic seal between the inner and outer race rings of the bearing and an o-ring between the outer race ring and the bearing housing. Moreover, as the bearing seal is located adjacent the axial outer face of the bearing, the bearing seal is easier to position. Also, with the static sealing member 14 having a diameter approximately equal to the diameter of the housing bore and the axially outwardly projecting lips having an outer diameter greater than the diameter of the housing bore, a secure positive seal between the static outer race ring and the housing can be provided. In addition, the bearing seal described can be more rigid than conventional dynamic seals which ensures a more reliable seal between the inner and outer race rings.

Claims: An annular bearing seal (10) comprising a substantially rigid radially extending sealing structure (11) having at an inner edge region an annular dynamic sealing element (18) and having at an outer edge region an annular static sealing element (14) which is mounted on an axially extending flange (13) on the sealing structure (11) and which extends axially away from the sealing structure, the static sealing element (14) including at least one deformable projection (23) radially outwardly of the static sealing element characterised in that there is provided a groove (22) in the static sealing element radially inwards of the or each deformable projection (23) and in that the static sealing element (14) is mounted to extend on both radially inner and outer surfaces of the axially extending flange (13). A bearing seal as claimed in claim 1, wherein the at least one deformable projection (23) comprises an opposing pair of lips (23) capable of radially inward deflection. A bearing seal as claimed in claim 2, wherein the static sealing element (14) includes respective grooves (22) in the static sealing element radially inwards of the deflectable lips (23). A bearing seal as claimed in any one of the preceding claims, wherein the dynamic sealing (18) element includes an elastohydrodynamic seal (17). A bearing (2) having an inner race ring (3), an outer race ring (4), rolling elements (8) therebetween and a bearing seal (10) as claimed in any one of claims 1 to 4, the outer race ring (4) including a recess (6) open to an axial outer face in which the static sealing element (14) is located. A bearing as claimed in claim 5, wherein the outer radial diameter of the at least one deformable projection (23) is greater than the outer diameter of the outer race ring (4). A bearing as claimed in either of claims 5 or 6, wherein the minimum inner diameter of the static sealing element (14) is substantially equal to the diameter of the recess (6). A bearing as claimed in either of claims 5 or 6, wherein the recess (6) includes a ridge (25) for engagement with an inner shoulder (26) on the static sealing element (14). A bearing as claimed in either of claims 5 or 6, wherein an O-ring (28) is provided in a groove (27) in the recess (6) for engagement with an inner shoulder (26) on the static sealing element (14). A bearing housing (5) including a bearing (2) as claimed in any one of claims 5 to 9 and a bearing seal (10) as claimed in any one of claims 1 to 4, wherein the outer radial diameter of the at least one deformable projection (23) is greater than the diameter of the housing bore.

Inventors: DUVAL ROLAND, GASSMANN ROLAND, STURMAN GRAHAM, DUVAL, ROLAND, GASSMANN, ROLAND, STURMAN, GRAHAM
Applicants: TIMKEN CO, THE TIMKEN COMPANY
Application year: 1996
Main classification: F16C33
IPC codes: F16C19, F16C33, F16J15