Fan blade dovetail and spacer

Patent metadata

Field	Value
Publication number	US-10408068-B2
Application number	US-201414773927-A
Country	US
Kind code	B2
Filing date	Feb 18, 2014
Priority date	Mar 12, 2013
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

A blade according to an exemplary aspect of the present disclosure includes, among other things, a radially inner dovetail supporting a radially outer airfoil; and the dovetail having a radial thickness which is less in a circumferentially center portion of the dovetail than circumferentially opposing outer edges.

First claim

The invention claimed is:

1. A rotor assembly comprising:
a rotor;
a blade including a radially inner dovetail disposed adjacent the rotor and supporting a radially outer airfoil emending out way from the rotor;
the dovetail having a maximum width and having three radially inner bottom surfaces and a radial thickness, the radial thickness being less in a circumferentially center portion of the dovetail than circumferentially opposing outer edges, the circumferentially center portion of the dovetail defining one of the radially inner bottom surfaces that has a single concave shape;
a spacer disposed radially between the one radially inner bottom surface of the dovetail having the single concave shape and the rotor, the spacer including a radial outer surface matching a contour of the single concave shape of the one radially bottom surface of the center portion of the dovetail so that the radially outer surface of the spacer is received into and engagingly fitted against the single concave shape of the one radially inner bottom surface of the dovetail, the spacer further including two planar outer surfaces and a radially inner surface having a convex shape opposed from the radially outer surface, the two planar outer surfaces being spaced apart and respectively disposed intermediate the radially outer surface and the radially inner surface having the convex shape, and the radial outer surface of the spacer spans along a majority portion of the maximum width of the dovetail,
wherein the respective other two radially inner bottom surfaces of the dovetail constantly decrease from the circumferential outer edges of the dovetail in an inbound direction of the dovetail to directly transitionally connect to the one radially inner bottom surface of the dovetail having the single concave shape.

2. The rotor assembly of claim 1 , wherein the dovetail is formed of a material that differs from a material of the rotor.

3. The rotor assembly of claim 2 , wherein the rotor defines a slot dimensioned to receive the dovetail, the spacer includes the radially inner surface having the convex shape that matches a contour of the slot, and the two planar sidewalls each slope inwardly from the radial outer surface toward the radially inner surface with respect to an inbound direction of the spacer.

4. The rotor assembly of claim 1 , wherein the one radially inner bottom surface of the dovetail having the single concave shape is furthest from a rotational axis of the rotor at the circumferentially center portion of the dovetail.

5. The rotor assembly of claim 1 , wherein the blade is a fan blade.

6. A fan comprising;
a fan rotor having a plurality of slots, with the slots each receiving a fan blade;
the fan blades including an airfoil extending radially outwardly of a dovetail, the dovetail having a radial thickness which is less in a circumferentially center portion of the dovetail than circumferentially opposing outer edges, the circumferentially center portion of the dovetail including a radially inner surface having a single concave shape;
a spacer disposed radially between the radial inner surface of the dovetail and the fan rotor, wherein the spacer includes a radial outer surface matching a contour of the single concave shape of the radial inner surface of the dovetail so that the radially outer surface of the spacer is received into and fitted against the single concave shape of the radially inner surface of the dovetail; and
wherein the spacer includes a second radially inner surface having a convex shape that matches a contour of a respective one of the plurality of slots, the second radially inner surface opposed to the radial outer surface of the spacer, and the spacer includes opposed planar sidewalls that respectively slope inwardly from the radial outer surface toward the second radially inner surface.

7. The fan of claim 6 , wherein a bottom surface of the dovetail decreases constantly from the circumferential edges to the circumferentially central portion.

8. The fan of claim 6 , wherein the fan rotor is formed of a first material and the dovetails is formed of a second material that differs from the first material.

9. The fan of claim 6 , wherein the spacer defines a spring force such that the spacer loads against the radial inner surface of the dovetail during rotation of the fan rotor.

10. The fan of claim 9 , wherein the fan blade is a constructed of a first material, and the spacer is constructed of a second material that differs from the first material.

11. The fan of claim 10 , wherein the fan blade delivers a portion of airflow to a bypass flow path and another portion of airflow to a core flow path defined by a compressor section during rotation of the fan rotor.

12. A method of interfacing a dovetail and a fan rotor, comprising:
providing the fan rotor with a plurality of slots, with the slots receiving a fan blade, and the tan blades including an airfoil extending radially outwardly of the dovetail, the dovetail having a radial thickness which is less in a circumferentially center portion of the dovetail than circumferentially opposing outer edges, the circumferentially center portion of the dovetail including a radially inner surface having a single concave shape;
positioning a spacer radially between the radial inner surface of the dovetail and the fan rotor, the spacer loading against the radial inner surface of the dovetail during rotation of the tan rotor, and wherein the spacer includes a radial outer surface matching a contour of the single concave shape of the radial inner surface of the dovetail so that the radially outer surface of the spacer is received into and fitted against the single concave shape of the radially inner surface of the dovetail; and
wherein the spacer includes a second radially inner surface having a convex shape that matches a contour of a respective one of the plurality of slots, the second radially inner surface opposed to the radial outer surface of the spacer, and the spacer includes opposed planar sidewalls that respectively slope inwardly from the radial outer surface toward the second radially inner surface.

13. The method of claim 12 , wherein the radial inner surface of the dovetail defining the single concave shape is concave when the dovetail is not loaded.

14. The method of claim 13 , wherein the fan blade is a constructed of a first material, and the spacer is constructed of a second material that differs from the first material.

Assignees

• United Technologies Corp

Inventors

• Whitehurst Sean A
• Mccomb Patrick James
• Mckaveney Christopher S

Classifications

• F05D2250/712

  concave · CPC title

• F05D2250/711

  convex · CPC title

• F01D5/323

  Locking of axial insertion type blades by means of a key or the like parallel to the axis of the rotor · CPC title

• F05D2220/36

  specially adapted for the fan of turbofan engines · CPC title

• F01D5/02

  Blade-carrying members, e.g. rotors (rotors of non-bladed type F01D1/34; stators F01D9/00 {; selecting particular materials F01D5/28}) · CPC title