Bearing support
A bearing support is disclosed herein. The bearing support includes a pilot ring encircling an axis. The pilot ring is operable to be substantially-fixed in operation. The bearing support also includes a damper ring operable to receive an outer race of a bearing assembly. The bearing support also includes a fuse pin extending through aligned apertures in the pilot ring and the damper ring to prevent relative radial movement between the pilot ring and the damper ring up to a predetermined amount of loading. The fuse pin is operable to fracture in response to loading beyond the predetermined amount. The bearing support also includes a retainer extending through one of the pilot ring and the damper ring and fixed to the other of the pilot ring and the damper ring. The fuse pin is engaged with at least one of the first and second apertures through a heat shrink fit.
1. A bearing support comprising:
a pilot ring encircling an axis and operable to be substantially-fixed in operation;
a damper ring operable to receive an outer race of a bearing assembly and encircling said axis;
a fuse pin extending through aligned apertures in said damper ring and said pilot ring to prevent relative radial movement between said pilot ring and said damper ring up to a predetermined amount of loading, said fuse pin operable to fracture in response to loading beyond the predetermined amount;
a retainer extending through one of said damper ring and said pilot ring and fixed to the other of said damper ring and said pilot ring, said retainer operable to limit relative axial movement between said pilot ring and said damper ring, said retainer limiting relative axial movement when said fuse pin fractures in response to loading beyond the predetermined amount; and
wherein said fuse pin is engaged with at least one of said damper ring and said pilot ring through a heat shrink fit.
2. The bearing support of claim 1 wherein said fuse pin is engaged with both of said damper ring and said pilot ring through a heat shrink fit.
3. The bearing support of claim 1 further comprising:
a support housing encircling said axis and having a locating ring; and
a first lip extending along said axis from a pilot face of said pilot ring, wherein said first lip slips around said locating ring during assembly and wherein said support housing and said pilot ring are formed from materials having different coefficients of thermal expansion such that an interference fit is generated during operation after temperatures of said support housing and said pilot ring have risen above pre-operating temperature.
4. The bearing support of claim 3 wherein said support housing further comprises:
a second lip extending from said locating ring to contact said pilot ring at a position radially inward of said first lip and radially inward of said fuse pin.
5. The bearing support of claim 4 wherein said fuse pin includes a head positioned radially between said first and second lips and axially between said pilot ring and said support housing, wherein said head fills the axial gap between said pilot ring and said support housing and extends radially past both sides of said aperture in said pilot ring to at least partially fill the radial gap between said first and second lips.
6. The bearing support of claim 1 wherein a locating clearance gap is defined between said retainer and said pilot ring to prevent friction between said retainer and said pilot ring from affecting the predetermined amount of loading.
7. The bearing support of claim 1 wherein said damper ring further comprises:
a flange extending radially relative to said axis, said flange operable to limit movement of a bearing assembly along said axis.
8. The bearing support of claim 7 wherein said damper ring further comprises:
a plurality of spring bars extending along said axis between said flange and said fuse pin.
9. The bearing support of claim 8 wherein said pilot ring further comprises:
a flange extending radially relative to said axis, said flange operable to limit movement of a bearing along said axis; and
a plurality of spring bars extending along said axis between said flange and said fuse pin.
10. A method of manufacturing a bearing support comprising the steps of:
limiting relative axial movement between a damper ring operable to receive an outer race of a bearing assembly and a pilot ring operable to be substantially-fixed in operation with a fuse pin extending through aligned apertures in the damper ring and the pilot ring, the fuse pin operable to prevent relative radial movement between the pilot ring and the damper ring up to a predetermined amount of loading, wherein the fuse pin is operable to fracture in response to loading beyond the predetermined amount;
limiting relative axial movement between the pilot ring and the damper ring with a retainer extending through one of the damper ring and the pilot ring and fixed to the other of the damper ring and the pilot ring, the retainer limiting relative axial movement between the damper ring and the pilot ring when the fuse pin fractures in response to loading beyond the predetermined amount; and
engaging the fuse pin with at least one of the damper ring and pilot ring through a heat shrink fit.
11. The method of claim 10 further comprising the steps of:
positioning the damper ring and the pilot ring together in a fixture prior to said engaging step; and
forming the aligned apertures for the fuse pin in the damper ring and the pilot ring during said positioning step.
12. The method of claim 11 further comprising the step of:
finishing surfaces on the damper ring during said engaging step.
13. The method of claim 12 wherein said finishing step includes:
machining an inside diameter of the damper ring in which a bearing outer race is received as the insider diameter is fixed relative to a locating surface defined by the pilot ring.
14. The method of claim 11 further comprising the steps of:
forming squeeze film damper gaps in the damper ring; and
forming a radial flange on one of the damper ring and the pilot ring to carry axial thrust load of a bearing.
15. A turbine engine comprising:
a shaft operable to rotate about a centerline axis;
a bearing assembly supporting said shaft for rotation and having an inner race fixed to said shaft, a plurality of rollers disposed about said inner race, and an outer race encircling said plurality of rollers;
a damper ring operable to receive said outer race of a bearing assembly and encircling said centerline axis;
a pilot ring encircling said centerline axis and operable to be substantially-fixed in operation;
a fuse pin extending through apertures in said pilot ring and said damper ring to prevent relative radial movement between said pilot ring and said damper ring up to a predetermined amount of loading, said fuse pin operable to fracture in response to loading beyond the predetermined amount;
a retainer extending through one of said pilot ring and said damper ring and fixed to the other of said pilot ring and said damper ring, said retainer and operable to limit relative axial movement between said pilot ring and said damper ring, said retainer limiting relative axial movement when said fuse pin fractures in response to loading beyond the predetermined amount; and
wherein said fuse pin is engaged with at least one of said pilot ring and said damper ring through a heat shrink fit.
16. The turbine engine of claim 15 wherein said fuse pin is engaged with both of said pilot ring and said damper ring through a heat shrink fit.
17. The turbine engine of claim 16 further comprising:
a support housing encircling said centerline axis and having a locating ring;
a first lip cantilevered off of a pilot face of said pilot ring, wherein said first lip slips around said locating ring during assembly and wherein said support housing and said pilot ring are formed from materials having different coefficients of thermal expansion such that an interference fit between said locating ring and said first lip is generated during operation after temperatures of said support housing and said pilot ring rise above a predetermined temperature; and
wherein said interference fit is axially and radially spaced from said fuse pin relative to said centerline axis.
18. The turbine engine of claim 17 wherein said pilot ring and said damper ring abut and contact one another radially outward and radially inward of said fuse pin.
19. The turbine engine of claim 18 wherein said fuse pin has a length defined along said centerline axis and a substantially constant cross-section along said length with a narrowed portion positioned along said centerline axis where said pilot ring and said damper ring abut and contact one another.
20. The turbine engine of claim 19 wherein said outer race and said damper ring are fixed together at a first end along said centerline axis and squeeze film damper gaps are defined between said outer race and said damper ring at a second end along said centerline axis.