Axially spaced restricted damper

Abstract

A bearing assembly comprises a housing that includes a first housing surface and a second housing surface. The first and second housing surfaces are substantially axially parallel with respect to a rotor centerline. The bearing assembly also comprises a damped outer race that includes a first outer race surface radially adjacent to and opposing the first housing surface which is located radially interior to the first outer race surface. A second outer race surface is radially adjacent to and opposing the second housing surface which is located radially exterior to the second outer race surface. The housing comprises an oil passage that is configured to provide oil from an outlet to a first space between the first outer race surface and the first housing surface, and configured to provide oil to a second space radially between the second outer race surface and the second housing surface.

Claims

1. A bearing assembly, comprising: a bearing housing comprising a first bearing housing surface and a second bearing housing surface where the first and second bearing housing surfaces are substantially axially parallel with respect to a rotor centerline; a damped outer race, comprising a first outer race surface radially adjacent to and opposing the first bearing housing surface which is located radially interior to the first outer race surface; a first piston ring groove in the first outer race surface, where the first piston ring groove comprises a first piston ring that seals between the first bearing housing surface and the first outer race surface; a second outer race surface radially adjacent to and opposing the second bearing housing surface which is located radially exterior to the second outer race surface; and a second piston ring groove in the second outer race surface, where the second piston ring groove comprises a second piston ring that seals between the second bearing housing surface and the second outer race surface; where the bearing housing comprises an oil passage that is configured to provide oil from an outlet to a first space of axial length L.sub.1 radially between the first outer race surface and the first bearing housing surface, and configured to provide oil to a second space of axially length L.sub.2 radially between the second outer race surface and the second bearing housing surface.

2. The bearing assembly of claim 1, where the damped outer race is held axially adjacent to the bearing housing by a retainer ring.

3. The bearing assembly of claim 1, where the first piston seal is axially offset from the second piston seal.

4. The bearing assembly of claim 1, where the first piston seal is axially aligned with the second piston seal.

5. The bearing assembly of claim 1, where the oil passage extends in a substantially axial direction with respect to the rotor centerline to provide oil to a third space that connects the first space and the second space.

6. An assembly, comprising: a bearing housing comprising a first bearing housing surface and a second bearing housing surface where the first and second bearing housing surfaces are substantially parallel with respect to a rotor centerline; a damped outer race comprising a first outer race surface radially adjacent to and opposing the first bearing housing surface which is located radially interior to the first outer race surface; a first piston ring groove in the first outer race surface, where the first piston ring groove comprises a first piston ring that seals between the first bearing housing surface and the first outer race surface; a second outer race surface radially adjacent to and opposing the second bearing housing surface which is located radially exterior to the second outer race surface; a second piston ring groove in the second outer race surface, where the second piston ring groove comprises a second piston ring that seals between the second bearing housing surface and the second outer race surface; and a bearing radially interior to the damped outer race; where the bearing housing comprises a fluid passage configured to provide a fluid film to a first space radially between the first outer race surface and the first bearing housing surface, and configured to provide the fluid film to a second space radially between the second outer race surface and the second bearing housing surface to damp radial motion of the bearing.

7. The assembly of claim 6, where the fluid passage extends in a substantially axial direction with respect to the rotor centerline to provide oil to a third space that interconnects and provides oil to the first space and the second space.

8. The assembly of claim 7, where the first piston seal is axially offset from the second piston seal.

9. The assembly of claim 7, where the first piston seal is axially aligned with the second piston seal.

10. An assembly, comprising: a bearing housing comprising a first bearing housing surface and a second bearing housing surface where the first and second bearing housing surfaces are substantially parallel with respect to a rotor centerline; a damped outer race comprising a first outer race surface radially adjacent to and opposing the first bearing housing surface which is located radially interior to the first outer race surface; a second outer race surface radially adjacent to and opposing the second bearing housing surface which is located radially exterior to the second outer race surface; a rotary bearing radially interior to and radially adjacent to the damped outer race; a first piston ring groove in the first outer race surface, where the first piston ring groove comprises a first piston ring that seals between the first bearing housing surface and the first outer race surface; and a second piston ring groove in the second outer race surface, where the second piston ring groove comprises a second piston ring that seals between the second bearing housing surface and the second outer race surface; where the bearing housing comprises a passage configured to provide an lubricant to a first space radially between the first outer race surface and the first bearing housing surface, and provide lubricant to a second space radially between the second outer race surface and the second bearing housing surface to damp radial motion of the bearing.

11. The assembly of claim 10, where the first piston seal is axially offset from the second piston seal.

12. The assembly of claim 10, where the first piston seal is axially aligned with the second piston seal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cross-sectional view taken along a rotor centerline of a prior art gas turbine engine configured to form damping cavities for the forward and aft bearings supported by a centering spring.

(2) FIG. 2 is a cross-sectional view of a bearing assembly taken along a rotor centerline of a gas turbine engine showing radially separated damping cavities that combine to provide an effective damper length.

(3) FIG. 3 is a cross-sectional view of the bearing assembly of FIG. 2 taken along a rotor centerline to show the effective damper length L.sub.1+L.sub.2.

(4) FIG. 4 is a cross-sectional view of an alternative embodiment bearing assembly taken along a rotor centerline.

DETAILED DESCRIPTION

(5) It is noted that various connections and steps are set forth between elements in the following description and in the drawings (the contents of which are incorporated in this specification by way of reference). It is noted that these connections and steps are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities or a space/gap between the entities that are being coupled to one another.

(6) As discussed in the background set forth above, the prior art includes an arrangement as set forth in FIG. 1.

(7) Aspects of the disclosure may be applied in connection with a gas turbine engine.

(8) FIG. 2 is a cross-sectional view taken along a rotor centerline of a gas turbine engine showing radially separated damping cavities that combine to provide an effective damper length. A bearing assembly 102 includes a bearing housing 104 that comprises a first bearing housing surface 105 and a second bearing housing surface 106. The first and second bearing housing surfaces 105 and 106 are substantially parallel.

(9) The bearing assembly 102 also includes a damped outer race 108 that comprises a first outer race surface 110 radially adjacent to and opposing first bearing housing surface 105 which is located radially interior to the first outer race surface 110. A first piston ring groove 112 is located in the first outer race surface 110 and comprises a first piston ring 114 that seals between the first bearing housing surface 105 and the first outer race surface 110.

(10) A second outer race surface 116 is located radially adjacent to and opposing the second bearing housing surface 106 which is located radially exterior to the second outer race surface 116. A second piston ring groove 118 is located in the second outer race surface 116 and comprises a second piston ring 120 that seals between the second bearing housing surface 106 and the second outer race surface 116.

(11) Referring now to FIGS. 2 and 3, the bearing housing 104 further comprises an oil passage 122 that is configured to provide oil to a first space 124 of axial length L.sub.1 located radially between the first outer race surface 110 and the first bearing housing surface 105. The oil passage 122 is also configured to provide oil to a second space 126 of axially length L.sub.2 located radially between the second outer race surface 116 and the second bearing housing surface 106. Notably the radially divided spaces 124, 126 associated with axial lengths L.sub.1 and L.sub.2, respectively, allow the designer to achieve the desired axial damper length by sub-dividing the axial damper into radially separated segments that combine to provide the desired axial damper length. For example, rather than providing an axially contiguous damper segment L.sub.0 as shown in prior art FIG. 1, in one embodiment the damper segment may be sub-divided into radially separated segments. This innovation efficiently packages an effectively longer damper of length L.sub.1+L.sub.2 into an axially compressed space by stacking the surfaces of the damper between which damper oil film flows. This provides the desired rotor dynamic damping to meet the requirements for proper rotor dynamic behavior.

(12) The damped outer race 108 may be held axially adjacent to the bearing housing by a retainer ring 130.

(13) The first piston seal 114 may be axially offset from the second piston seal 120 as shown in FIGS. 2 and 3. Alternatively, the first piston seal 114 may be axially aligned with the second piston seal 120.

(14) The oil passage 122 may extend in a substantially axial direction to discharge oil to a third space 134 that radially connects the first space 124 and the second space 126. The oil film in the first and second spaces 124, 126 is contained between the surfaces of the bearing housing 104 and the damped outer race 108. The oil film pressure is maintained and the flow is restricted by the first and second piston seals 114 and 120, which are contained within the grooves 112, 118 respectively in the damped outer race 108. Radial motion of a bearing 140 is dynamically damped by the damper oil film in the first and second spaces 124, 126.

(15) FIG. 4 is a cross-sectional view of an alternative embodiment bearing assembly 200 taken along a rotor centerline. This embodiment is substantially the same as the embodiment illustrated in FIGS. 2 and 3, with the principal exception that the embodiment of FIG. 4 does not include piston rings and their associated grooves, and is generally referred to as an open damper assembly. In contrast, the embodiment illustrated in FIGS. 2 and 3 may be referred to as a closed damper arrangement since it includes the piston rings.

(16) Although the different non-limiting embodiments have specific illustrated components, the embodiments of this invention are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting embodiments in combination with features or components from any of the other non-limiting embodiments. For example, it is contemplated that the dirt separator for internally cooled components disclosed herein is not limited to use in vanes and blades, but rather may also be used in combustor components or anywhere there may be dirt within an internal flowing passage.

(17) It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom.

(18) The foregoing description is exemplary rather than defined by the features within. Various non-limiting embodiments are disclosed herein; however, one of ordinary skill in the art would recognize that various modifications and variations in light of the above teachings will fall within the scope of the appended claims. It is therefore to be understood that within the scope of the appended claims, the disclosure may be practiced other than as specifically described. For that reason the appended claims should be studied to determine true scope and content.