Radial shaft seal assembly with axially adaptive debris exclusion face lip and oil seal face lip

1. A radial shaft seal assembly, comprising:

an inner wear sleeve having a cylindrical inner wall with a bore sized for close receipt of a shaft therethrough and an exposed cylindrical outer surface, said inner wear sleeve having an oil side flange and an air side flange extending radially outwardly from said cylindrical inner wall in axially spaced relation from one another;

an outer case having cylindrical outer wall configured for receipt in a housing;

an elastomeric body fixed to said outer case, said elastomeric body including an annular serpentine portion extending radially inwardly from said outer wall to a radially innermost end;

a main seal lip extending from said innermost end of said annular serpentine portion into sealed contact with said oil side flange; and

a dust lip fixed to said annular serpentine portion and extending into sealed contact with said air side flange.

2. The radial shaft seal assembly of claim 1 wherein said main seal lip remains spaced radially outwardly from said exposed cylindrical outer surface in its entirety.

3. The radial shaft seal assembly of claim 1 wherein said main seal lip diverges radially outwardly from said innermost end.

4. The radial shaft seal assembly of claim 1 wherein said dust lip and said main seal lip extend in opposite axial directions from said innermost end.

5. The radial shaft seal assembly of claim 1 wherein said dust lip is plastic.

6. The radial shaft seal assembly of claim 1 wherein said dust lip has a radially extending annular face in abutment with said air side flange, said annular face having at least one pumping member configured to pump debris radially outwardly and axially away from said main seal lip toward an air side of the seal assembly.

7. The radial shaft seal assembly of claim 1 wherein said main seal lip is formed as a monolithic piece of the same material with said elastomeric body.

8. The radial shaft seal assembly of claim 1 wherein said inner wear sleeve has a radially outer member forming one of said oil side flange and said air side flange and a radially inner member forming the other of said oil side flange and said air side flange, said radially outer member and said radially inner member being press fit into fixed relation with one another.

9. The radial shaft seal assembly of claim 8 wherein said radially inner member forms said bore.

10. The radial shaft seal assembly of claim 9 wherein said radially inner member forms said exposed cylindrical outer surface.

11. The radial shaft seal assembly of claim 9 wherein said radially outer member forms said exposed cylindrical outer surface.

12. The radial shaft seal assembly of claim 1 wherein said oil side flange extends radially outwardly to a frustroconical free edge diverging toward an oil side of the seal assembly.

13. The radial shaft seal assembly of claim 1 wherein said air side flange extends radially outwardly to a serpentine end region meandering toward an air side of the seal assembly.

14. The radial shaft seal assembly of claim 13 wherein said serpentine end region includes a cylindrical inner portion and a cylindrical outer portion with an intermediate portion extending radially between said cylindrical inner and outer portions.

15. The radial shaft seal assembly of claim 1 wherein said outer case has a radially inwardly extending annular lip, said annular serpentine portion extends radially inwardly from said annular lip in radial alignment therewith.

16. The radial shaft seal assembly of claim 15 wherein at least a portion of said annular serpentine portion extends axially outwardly from said annular lip toward said oil side flange.

17. The radial shaft seal assembly of claim 15 wherein said dust lip is radially aligned with said annular lip.

18. The radial shaft seal assembly of claim 1 wherein said outer case has a cylindrical inner surface, said annular serpentine portion extends radially inwardly from said cylindrical inner surface in radial alignment therewith.

19. The radial shaft seal assembly of claim 1 wherein said air side flange has at least one vent opening extending therethrough.

20. The radial shaft seal assembly of claim 19 wherein said at least one vent opening extends into an annular gap radially inwardly from said dust lip.

21. The radial shaft seal assembly of claim 19 further including an annular filter member disposed adjacent said at least one vent opening.

22. The radial shaft seal assembly of claim 21 wherein said air side flange extends between said dust lip and said filter member.

23. The radial shaft seal assembly of claim 1 further including a secondary seal lip extending from said serpentine portion toward an air side of the assembly.

24. The radial shaft seal assembly of claim 23 wherein the secondary seal lip extends into sealed contact with said air side flange.

25. The radial shaft seal assembly of claim 23 wherein the secondary seal lip is spaced in its entirety from said air side flange.

26. The radial shaft seal assembly of claim 25 further including an annular filter member disposed adjacent said secondary seal lip in axially spaced relation therefrom.

27. The radial shaft seal assembly of claim 26 wherein said annular filter member is axially aligned with said serpentine portion in axially spaced relation therefrom.

28. The radial shaft seal assembly of claim 1 wherein said annular serpentine portion is flexible in axial and radial directions.