Intershaft seal assembly

Patent metadata

Field	Value
Publication number	US-10520096-B2
Application number	US-201615288079-A
Country	US
Kind code	B2
Filing date	Oct 7, 2016
Priority date	Nov 2, 2015
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

An intershaft seal assembly comprises an annular seal ring disposed between a pair of annular runners connected to a hollow outer rotating shaft, and a surface of a co-axial inner rotating shaft. The centrifugal force resulting from rotation of the hollow outer rotating shaft effects engagement of the annular seal ring with the surface of the co-axial inner rotating shaft. The surface may be a radially-inward-facing surface of a retaining arm connected to the co-axial inner rotating shaft.

First claim

What is claimed is:

1. A seal assembly for sealing a higher pressure fluid cavity from a lower pressure fluid cavity, the seal assembly comprising:
a hollow rotatable shaft having an outer surface;
a co-axial rotatable shaft at least partially disposed within the hollow rotatable shaft, wherein the hollow rotatable shaft and the co-axial rotatable shaft at least partly define the higher pressure fluid cavity and the lower pressure fluid cavity;
a pair of annular axially-spaced runners attached to the outer surface of the hollow rotatable shaft, the runners having opposed axially-facing radially-extending side surfaces;
an annular seal ring positioned between said runners, the annular seal ring having a radially-outward facing surface; and
an annular retaining arm attached to the co-axial rotatable shaft at a portion of the co-axial rotatable shaft not disposed within the hollow rotatable shaft, the annular retaining arm comprising a first portion extending radially from the co-axial rotatable shaft and a second portion extending axially from the first portion, the second portion defining a radially-inward facing surface positioned radially outward of a portion of the hollow rotatable shaft and the annular seal ring, wherein a radial height of the first portion of the retaining arm is greater than a radial height of the pair of annular axially-spaced runners;
wherein rotation of the hollow rotatable shaft effects engagement of said radially-outward facing surface of said annular seal ring with said radially-inward facing surface of said retaining arm.

2. The seal assembly of claim 1 wherein said hollow rotatable shaft and said co-axial rotatable shaft are adapted for counter-rotation.

3. The seal assembly of claim 1 wherein said hollow rotatable shaft and said co-axial rotatable shaft are adapted for co-rotation.

4. The seal assembly of claim 1 wherein said hollow rotatable shaft is connected to at least one of a plurality of compressor blades or a plurality of turbine blades.

5. The seal assembly of claim 4 wherein said co-axial rotatable shaft is connected to at least one of a plurality of fan blades, a plurality of compressor blades, or a plurality of turbine blades.

6. The seal assembly of claim 1 further comprising a spacer between said pair of axially-spaced runners.

7. The seal assembly of claim 1 further comprising a plurality of hydrodynamic grooves formed in the axially-facing radially-extending side surfaces of said pair of axially-spaced runners.

8. An intershaft seal assembly comprising:
a hollow rotatable shaft defining an axis of rotation, the hollow rotatable shaft extending axially to a terminus and having a radially outer shaft surface and a radially inner shaft surface;
a co-axial rotatable shaft at least partially disposed within and extending axially beyond the terminus of the hollow rotatable shaft;
a pair of axially-spaced annular runners connected to said radially outer shaft surface of said hollow rotatable shaft;
an annular seal ring disposed between said runners at a first axial position, said annular seal ring having a radially-outward facing seal surface;
a retaining arm connected to said co-axial rotatable shaft, the retaining arm comprising a radially-extending portion at a second axial position displaced from the first axial position and an axially-extending portion having a radially-inward facing surface positioned radially outward of the terminus and the first axial position, wherein a radial height of the radially-extending portion of the retaining arm is greater than a radial height of the pair of axially-spaced annular runners;
a first fluid cavity at least partly defined between the radially inner shaft surface of the hollow rotatable shaft and the co-axial rotatable shaft; and
a second fluid cavity at least party defined by the radially outer shaft surface of the hollow rotatable shaft;
wherein the rotation of said hollow rotatable shaft effects engagement of said radially-outward facing surface of said annular seal ring with said radially-inward facing surface of said retaining arm to thereby form a boundary between said first fluid cavity and said second fluid cavity.

9. The intershaft seal assembly of claim 8 wherein said runners are connected to said hollow rotatable shaft via a connecting arm comprising a radially-extending member and an axially-extending member, wherein said runners are connected to a radially-outward facing surface of said axially-extending member.

10. The intershaft seal assembly of claim 8 wherein said hollow rotatable shaft is adapted to rotate at a higher rotational speed than said co-axial rotatable shaft.

11. The intershaft seal assembly of claim 10 wherein said hollow rotatable shaft is adapted to counter-rotate said co-axial rotatable shaft.

12. The intershaft seal assembly of claim 10 wherein said hollow rotatable shaft is adapted to co-rotate said co-axial rotatable shaft.

13. The intershaft seal assembly of claim 12 , said annular seal ring further having axially-facing radially-extending side faces which are spaced from axially-facing radially-extending side faces of said runners.

14. The intershaft seal assembly of claim 13 further comprising a spacer between said pair of axially-spaced runners.

15. The intershaft seal assembly of claim 14 wherein said hollow rotatable shaft is connected to at least one of a plurality of blades of a high pressure compressor stage or a plurality of blades of a high pressure turbine stage.

16. The intershaft seal assembly of claim 15 wherein said co-axial rotatable shaft is connected to at least one of a plurality of fan blades of a turbine fan, a plurality of blades of a low pressure compressor stage, or a plurality of blades of a low pressure turbine stage.

17. The seal assembly of claim 13 further comprising a plurality of hydrodynamic grooves formed in the axially-facing radially-extending side surfaces of said pair of axially-spaced runners.

18. The seal assembly of claim 8 wherein the seal ring has a U-shaped cross section.

Assignees

• Rolls Royce Corp

Inventors

• Munson John

Classifications

• F04D29/102

  especially adapted for elastic fluid pumps · CPC title

• F05D2240/61

  Hollow · CPC title

• F16J15/441

  with floating ring · CPC title

• F05D2240/55

  Seals · CPC title

• F16J15/4476 Primary

  with radial path · CPC title