Patent Application
20130051986
1. Technical Field
This disclosure relates generally to a gas turbine engine and, more particularly, to a shaft assembly for a gas turbine engine.
2. Background Information
Various shaft assemblies for gas turbine engines are known in the art. One type of shaft assembly includes an engine shaft, a rotor disc, a stack nut and a stack nut lock. The rotor disc is mounted on the shaft between a shaft shoulder and the nut. The nut lock is disposed on the nut, and includes a plurality of protrusions. A first set of the protrusions extend into corresponding notches in the shaft. A second set of the protrusions extend into corresponding notches in the nut. The nut lock therefore interlocks the nut with the shaft and, thus, prevents the nut from rotating relative to the shaft during engine operation.
The aforesaid nut lock may be manufactured using a combined forging and machining process. The combined forging and machining process, however, typically involves long machining times, and requires relatively large quantities of material as the nut lock is machined out of the forging.
According to an aspect of the invention, a shaft assembly is provided that includes a shaft, a nut, a nut lock ring and a tubular nut support ring. The shaft includes a nut base mounted on the shaft, and a plurality of protrusions that extend radially out from the nut base. Adjacent protrusions are circumferentially separated by a gap. The nut lock ring includes a tubular ring base connected axially between a plurality of first lock tabs and a plurality of second lock tabs. The ring base is disposed on the nut base. Each first lock tab extends radially inward through a respective one of the notches. Each second lock tab extends axially through a respective one of the gaps. The nut support ring is disposed on the ring base.
The nut lock ring may be manufactured from a length of metal tube stock or sheet metal. The nut support ring may be manufactured from a length of metal tube stock or sheet metal.
The foregoing features and the operation of the invention will become more apparent in light of the following description and the accompanying drawings.
The shaft 12 is rotatable about an axial centerline 20. Referring to
The lock nut system 18 includes a nut 40 (e.g., a spanner nut), a nut lock ring 42 and a tubular nut support ring 44. The nut 40 includes a nut base 46 and a plurality of protrusions 48. The nut base 46 extends axially between a first nut end 50 and a second nut end 52, and extends radially between a threaded nut bore 54 and an outer radial lock ring contact surface 56. The protrusions 48 extend radially out from the nut base 46. The protrusions 48 are disposed axially between the lock ring contact surface 56 and the second nut end 52. The adjacent protrusions 48 are circumferentially separated by a gap 58.
Referring to
Each first lock tab 62 includes a corner tab segment 78 connected between a first base tab segment 80 and a first end tab segment 82. The first base tab segment 80 extends axially, for example substantially parallel to the centerline 20, from the first base segment end 72 to the corner tab segment 78. The first base tab segment 80 has a base tab segment thickness 84 that is, for example, greater than or equal to the nut contact segment thickness 76. The first end tab segment 82 extends radially, for example substantially perpendicular to the centerline 20, from the corner tab segment 78 to a distal first lock tab end 86.
Each second lock tab 64 includes a second base tab segment 88 and a second end tab segment 90. The second base tab segment 88 extends axially, for example substantially parallel to the centerline 20, from the second base segment end 74 to the second end tab segment 90. The second end tab segment 90 extends axially from the second base tab segment 88 to a distal second lock tab end 92. The second end tab segment 90 may be canted radially outwards relative to the second base tab segment 88.
Each third lock tab 66 extends radially outwards from the first base segment end 72 to a distal third lock tab end 91. Referring to
Referring to
Referring to
Referring again to
During engine operation, the nut lock ring 42 prevents the nut 40 from rotating relative to the shaft 12 and, thus, loosening or detaching from the shaft 12. The nut support ring 44 structurally reinforces the nut lock ring 42 and the nut 40. The nut support ring 44 may also aid in holding the nut 40 together where the nut 40 fractures.
The nut lock ring 42 may be manufactured (e.g., machined, cut, bent, etc.) from a length of metal tube stock. Alternatively, the nut lock ring 42 may be manufactured from sheet metal. The nut support ring 44 may be manufactured from a length of metal tube stock. Alternatively, the nut support ring 44 may be manufactured from sheet metal. By manufacturing (e.g., machining, cutting, bending, etc.) the nut lock ring 42 and/or the nut support ring 44 from tube stock and/or sheet metal, associated manufacturing time and waste material may be reduce relative to forging and machining a typical nut lock as described in the background.
While various embodiments of the present invention have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. Accordingly, the present invention is not to be restricted except in light of the attached claims and their equivalents.
