Floating brush seal assembly
A floating brush seal assembly includes a ring-shaped housing defining a radially inwardly open internal cavity; a brush seal in the cavity and having bristles extending radially inwardly and offset to seal against a rotating body; a radial spring positioned to exert a radial inwardly directed force against the brush seal relative to the housing; and an axial spring positioned to exert an axially directed force against the brush seal relative to the housing.
1. A floating brush seal assembly, comprising:
a ring-shaped housing defining a radially inwardly open internal cavity;
a brush seal in the cavity and having bristles extending radially inwardly and offset to seal against a rotating body;
a radial spring positioned to exert a radial inwardly directed force against the brush seal relative to the housing; and
an axial spring positioned to exert an axially directed force against the brush seal relative to the housing, wherein the housing has a backing plate and a side plate defining the cavity therebetween, and wherein the brush seal is between the backing plate and the side plate, and wherein the side plate is slidable axially into the backing plate, and further comprising a retaining device for securing the side plate to the backing plate, wherein the backing plate has a radially extending component and an axially extending component, and wherein the side plate is radially enclosed by the axially extending component of the backing plate.
2. The assembly of claim 1 , wherein the axial spring is between the side plate and the brush seal.
3. The assembly of claim 1 , wherein the brush seal comprises a ring-shaped bristle holder, and wherein the bristles extend radially inwardly from the bristle holder.
4. The assembly of claim 3 , further comprising cut out areas in at least one of the bristle holder and the backing plate to reduce contact area between the bristle holder and the backing plate.
5. The assembly of claim 4 , further comprising a friction reducing coating at points of contact between the bristle holder and the backing plate.
6. The assembly of claim 3 , further comprising an anti-rotation member defined between the bristle holder and the housing to prevent rotation of the bristle holder relative to the housing.
7. The assembly of claim 3 , wherein a floating gap is defined between a radially inwardly facing surface of the cavity and a radially outwardly facing surface of the bristle holder, and wherein the radial spring is positioned in the floating gap.
8. The assembly of claim 3 , wherein the bristle holder is radially elastic so that a radial excursion of the rotating body against the brush seal moves the brush seal toward the radial spring, and the radial spring returns the bristle holder to a centered position after the radial excursion.
9. The assembly of claim 3 , wherein combined force of the radial spring and force of friction between the bristle holder and the backing plate is less than or equal to expected force from an excursion of the rotating body through the bristles to the bristle holder.
10. The assembly of claim 1 , further comprising a drain hole in the housing to allow collected oil to flow past the seal assembly.
11. The assembly of claim 1 , wherein the axial spring comprises a flat ring having spring tabs elastically extending out of a plane of the flat ring to press against the brush seal.
12. The assembly of claim 1 , wherein the radial spring comprises a resilient ring positioned between the housing and the brush seal to maintain the brush seal centered relative to the housing.
13. A floating brush seal assembly, comprising:
a ring-shaped housing defining a radially inwardly open internal cavity;
a brush seal in the cavity and having bristles extending radially inwardly and offset to seal against a rotating body, wherein the brush seal is radially free-floating relative to the housing;
an axial spring positioned to exert an axially directed force against the brush seal relative to the housing, wherein the housing has a backing plate and a side plate defining the cavity therebetween, and wherein the brush seal is between the backing plate and the side plate, and wherein the side plate is slidable axially into the backing plate, and further comprising a retaining device for securing the side plate to the backing plate; and
wherein the backing plate has a radially extending component and an axially extending component, and wherein the side plate is radially enclosed by the axially extending component of the backing plate.
14. The assembly of claim 1 , wherein the retaining device is mounted in a groove in the backing plate and extends radially inwardly from the groove to capture the side plate within the backing plate.