Shaft seal having integrated removal feature
View Patent ↗A dynamic shaft seal assembly has inner and outer cases that are clamped together to secure a seal element therebetween for dynamic sealing about a rotatable shaft. The inner case is formed with integral pull tabs that are engageable by a seal removal tool to facilitate the removal of the seal assembly from a bore in which the seal assembly is installed.
1. A dynamic seal assembly, comprising:
an outer annular case having an axially-extending cylindrical mounting portion with an outer end at least partially curled radially-inward and also having a radially-extending flange portion;
an inner annular case nested in said outer annular case and having an axially-extending cylindrical portion with an end abutting said outer end to lock said cases together and a radially-extending flange portion with a distal end defining a mouth edge;
an annular seal element disposed between said respective flanges portions of said inner and outer cases under a compressive load at a radially outward end and having a cantilevered lip extending radially inward from said radially outward end, said flange portion of said inner annular case extending more radially inward than said flange portion of said outer annular case such that said lip bends axially away from said inner annular case in operation; and
a plurality of integral pull tabs circumferentially spaced from one another about said mouth edge and formed as one piece with said inner case of the same material, said plurality of tabs being closer to a point where said inner annular case abuts said outer end of said outer annular case than said annular seal element, and said plurality of tabs extending radially and axially away from said mouth edge to thereby define an unoccupied cavity for engagement by a seal removal tool to concurrently remove the entire assembly without changing the compressive load on said annular seal element.
2. The assembly of claim 1 wherein said inner case has an inner clamping face engaging said seal element and terminating at said plurality of tabs.
3. The assembly of claim 1 wherein said pull tabs project away from said inner clamping face at an acute angle.
4. The assembly of claim 3 wherein said angle is about 30 degrees.
5. The assembly of claim 2 wherein said inner clamping surface is generally perpendicular to a longitudinal axis of the inner case.
6. The assembly of claim 1 wherein said pull tabs are exposed to an air side of said seal assembly and do not compromise a sealing capacity of the assembly.
7. The assembly of claim 1 wherein said outer end of said outer annular case supports said inner annular case against axial separation from said outer inner annular case in response to application of an axially outer seal-removing pull force applied to said pull tabs.
8. The assembly of claim 1 wherein said inner case is a one-piece stamped metal member.
9. A method of removing a dynamic shaft seal assembly from a bore, said method comprising:
disposing an annular seal element under compressive load between nested and generally L-shaped outer and inner annular cases that are axially locked with respect to one another;
extending a plurality of pull tabs from a mouth edge of the inner annular case both radially and axially away from the mouth edge to increase a cross-sectional area of pull surfaces defined by the plurality of pull tabs and avoid destructive contact with the annular seal;
engaging the pull tabs with a seal removal tool from an air side of the seal assembly; and
applying an axial pulling force on the pull tabs to withdraw the seal assembly without changing the compressive load on the annular seal element.
10. The method of claim 9 wherein the tool is engaged by first axially extending the tool through spaces between the pull tabs and then rotating the tool about a longitudinal axis of both the inner and outer annular cases to position tab-engaging features of the tool axially behind the pull tabs.