Frangible mounting arrangement and method for providing same

Patent metadata

Field	Value
Publication number	US-10190439-B2
Application number	US-201414259558-A
Country	US
Kind code	B2
Filing date	Apr 23, 2014
Priority date	Apr 23, 2014
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

A frangible mounting arrangement between a bearing and a bearing support in a gas turbine engine comprises a plurality of frangible bolts connecting mounting flanges of the bearing and the bearing support. The bolts are disposed on a circle. A distance on the circle between a first pair of adjacent bolts is greater than a distance on the circle between a second pair of adjacent bolts. The bolts are configured to break when subjected to a breaking load above a predetermined value. The breaking load results from at least one of a bending moment and a shear load on the mounting flanges. When subjected to the breaking load, the first pair of adjacent bolts breaks before the second pair of adjacent bolts. A method of providing a frangible mounting arrangement between a bearing and a bearing support is also provided.

First claim

The invention claimed is:

1. A frangible mounting arrangement comprising:
a thrust bearing for carrying axial loads,
a bearing support; and
a plurality of frangible bolts connecting respective mounting flanges of the thrust bearing and the bearing support, the mounting flange of the thrust bearing extending from an outer race of the thrust bearing, the plurality of frangible bolts extending axially and being disposed on a circle and including a first pair of adjacent frangible bolts and a second pair of adjacent frangible bolts, the circle free of bolts between frangible bolts of the first pair of adjacent frangible bolts and free of bolts between frangible bolts of the second pair of adjacent frangible bolts, a distance (d 1 ) on the circle between the frangible bolts of the first pair of adjacent frangible bolts being greater than a distance (d 2 ) on the circle between the frangible bolts of the second pair of adjacent frangible bolts, the plurality of frangible bolts being configured to break when subjected to a same breaking load above a predetermined value, the breaking load resulting from at least one of a bending moment and a shear load on the mounting flanges.

2. The arrangement as defined in claim 1 , wherein the arrangement is free of bolts other than the plurality of frangible bolts.

3. The arrangement as defined in claim 1 , wherein the plurality of frangible bolts consists of a set of identical bolts.

4. The arrangement as defined in claim 1 , wherein the plurality of frangible bolts includes nine frangible bolts grouped in three groups disposed at 120 degrees from each other, the first pair of adjacent frangible bolts corresponding to frangible bolts belonging each to one of two adjacent of the three groups, and the second pair of frangible bolts corresponding to frangible bolts belonging each to a same one of the three groups.

5. A turbofan gas turbine engine comprising a rotor including a shaft coupled to a propulsive fan, a plurality of axially spaced-apart bearing assemblies supporting the shaft on a stator structure of the turbofan gas turbine engine, one of said bearing assemblies having a frangible mounting arrangement as defined in claim 1 .

6. A frangible bearing arrangement comprising:
a thrust bearing for carrying axial loads;
a bearing support; and
a plurality of identical frangible bolts connecting respective mounting flanges of the thrust bearing and the bearing support, the mounting flange of the thrust bearing defined by an outer race of the thrust bearing, the frangible bolts extending in an axial direction and breaking above a selected breaking load, the breaking load resulting from at least one of a bending moment and a shear load on the mounting flanges, a circumferential spacing (d 1 ) between a first and a second adjacent bolt of the plurality of frangible bolts is greater than a circumferential spacing (d 2 ) between the second and a third adjacent bolt of the plurality of frangible bolts, wherein the plurality of frangible bolts includes at least nine frangible bolts grouped in three groups, the three groups being at 120 degrees from each other.

7. A turbofan gas turbine engine comprising the frangible mounting arrangement defined in claim 6 , and a shaft carrying a fan.

8. The arrangement as defined in claim 6 , wherein the plurality of frangible bolts consists of a plurality of identical frangible bolts.

9. A method of mounting a thrust bearing to a bearing support via a frangible mounting arrangement in a gas turbine engine, the thrust bearing mountable to the bearing support via respective mounting flanges, the mounting flange of the thrust bearing extending radially from an outer race thereof relative to a central axis of the gas turbine engine, the method comprising:
connecting the respective mounting flanges of the thrust bearing and the bearing support with at least first and second groups of frangible bolts, the frangible bolts of the at least first and second groups being disposed on a circle, the at least first and second groups being spaced from one another by a first distance (d 1 ) on the circle, the circle free of bolts between the first group and the second group, the first group of frangible bolts being adjacent to the second group of frangible bolts, the frangible bolts within each of the at least first and second groups being spaced by a second distance (d 2 ) on the circle, the second distance (d 2 ) being smaller than the first distance (d 1 ), the frangible bolts of the first and second groups being configured to break when subjected to a breaking load above a same predetermined value, the breaking load resulting from at least one of a bending moment and a shear load on the mounting flanges.

10. The method defined in claim 9 , wherein the at least first and second groups comprise a third group of frangible bolts, the method comprising uniformly distributing the first, second and third groups on the circle.

11. The method defined in claim 9 , wherein the at least first and second groups comprise a third group of frangible bolts, the method comprising unevenly spacing the first, second and third groups on the circle.

12. The method defined in claim 9 , comprising providing different numbers of frangible bolts in the at least first and second groups.

13. The method defined in claim 9 , comprising varying the second distance (d 2 ) between the frangible bolts of a same group of the at least first and second groups.

Assignees

• Pratt & Whitney Canada

Inventors

• Korshikov Oleg
• Wojtyczka Czeslaw
• Denis David

Classifications

• F05D2260/311

  of the frangible or shear type · CPC title

• F01D21/045 Primary

  special arrangements in stators or in rotors dealing with breaking-off of part of rotor · CPC title

• F16C35/045

  with a radial flange to mount the housing · CPC title