| US 7,476,085 B2 | ||
| Blade/disk dovetail backcut for blade/disk stress reduction (6FA+E, stage2) | ||
| Patrick J. Mohr, Greer, S.C. (US); Emilio Fernandez, Taylors, S.C. (US); Anil B. Rajanna, Karnataka State (India); Seerangan Murugesan, Karnataka State (India); and Kamlesh Dewangan, Kranataka State (India) | ||
| Assigned to General Electric Company, Schenectady, N.Y. (US) | ||
| Filed on Jun. 28, 2006, as Appl. No. 11/476,097. | ||
| Application 11/476097 is a continuation of application No. PCT/US2006/018473, filed on May 12, 2006. | ||
| Prior Publication US 2008/0260535 A1, Oct. 23, 2008 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. F01D 5/30 (2006.01) | ||
| U.S. Cl. 416—219R [416/248] | 12 Claims |
| 1. A method for reducing stress on at least one of a turbine disk and a turbine blade, wherein a plurality of turbine blades
are attachable to the disk, and wherein each of the turbine blades includes a blade dovetail engageable in a correspondingly-shaped
dovetail slot in the disk, the blade dovetail including three tangs as a wide tang, a middle tang, and a narrow tang, the
method comprising:
(a) determining a start point for a dovetail backcut relative to a datum line, the start point defining a length of the dovetail
backcut along a dovetail axis;
(b) determining a cut angle for the dovetail backcut; and
(c) removing material from at least one of the blade dovetail or the disk dovetail slot according to the start point and the
cut angle to form the dovetail backcut,
wherein the start point and the cut angle are optimized according to blade and disk geometry to maximize a balance between
stress reduction on the disk, stress reduction on the blade, a useful life of the turbine blades, and maintaining or improving
the aeromechanical behavior of the turbine blade,
wherein the datum line is positioned 1.936 inches from a forward face of the blade dovetail along a centerline of the dovetail
axis, and wherein step (a) is practiced such that the start point of the dovetail backcut is at least 0.923 inches in an aft
direction from the datum line for the wide tang and at least 1.654 inches in the aft direction from the datum line for the
middle tang.
|