U.S. patent application number 10/041580 was filed with the patent office on 2002-07-11 for mounting arrangement for fixing a fan blade to a disk of a turbojet engine.
Invention is credited to Douguet, Charles Jean-Pierre, Judet, Maurice Guy, Lejars, Claude Robert Louis, Nitre, Thierry.
Application Number | 20020090300 10/041580 |
Document ID | / |
Family ID | 8858676 |
Filed Date | 2002-07-11 |
United States Patent
Application |
20020090300 |
Kind Code |
A1 |
Douguet, Charles Jean-Pierre ;
et al. |
July 11, 2002 |
Mounting arrangement for fixing a fan blade to a disk of a turbojet
engine
Abstract
A turbojet engine fan rotor including a rotor disk having a
peripheral rim with a plurality of axially extending channels
carrying a plurality of fan blades each having a blade root
interengaging with the channels of the disk, and a mounting
arrangement for securing the blades to the disk. The mounting
arrangement includes an annular member having a plurality of
radially extending teeth, a plurality of wedges each interposed
between one of the blade roots and a corresponding one of the
channels and including a radially extending boss provided at one
end, and a plurality of radially extending protrusions from the
disk. The plurality of teeth and the plurality of protrusions
cooperate with one another to secure the annular member with the
rotor disk.
Inventors: |
Douguet, Charles Jean-Pierre;
(Vulaines S / Seine, FR) ; Judet, Maurice Guy;
(Dammarie Les Lys, FR) ; Lejars, Claude Robert Louis;
(Draveil, FR) ; Nitre, Thierry; (Brunoy,
FR) |
Correspondence
Address: |
BACON & THOMAS, PLLC
625 SLATERS LANE
FOURTH FLOOR
ALEXANDRIA
VA
22314
|
Family ID: |
8858676 |
Appl. No.: |
10/041580 |
Filed: |
January 10, 2002 |
Current U.S.
Class: |
416/220R ;
415/220 |
Current CPC
Class: |
F01D 5/323 20130101;
F01D 5/3015 20130101 |
Class at
Publication: |
416/220.00R ;
415/220 |
International
Class: |
F01D 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 11, 2001 |
FR |
0100294 |
Claims
We claim:
1. A turbojet engine fan rotor including a rotor disk having a
central axis and a peripheral rim with a plurality of axially
extending channels at spaced apart angular intervals, a plurality
of fan blades carried by said rim, each of said fan blades having a
blade root interengaging with one of said channels of the rim of
the disk and having surfaces configured and dimensioned
corresponding to axially facing surfaces of said channels, and a
mounting arrangement for securing said blades to said disk, said
mounting arrangement comprising: an annular member having a
plurality of teeth radially extending therefrom and spaced apart at
regular angular intervals, said annular member having a radially
inner portion fastened to a radially inner portion of said disk; a
plurality of wedges each interposed between one of said blade roots
and a corresponding one of said channels, each of said wedges
having a radially extending boss provided at one end and axially
interposed between said annular member and said blade roots; and
said disk having a plurality of radially extending protrusions
spaced apart at intervening angular intervals relative to said
channels and disposed at angular positions of said plurality of
teeth, said plurality of protrusions being arranged to overlap
simultaneously with said plurality of teeth such that upon axial
displacement of said blades, said plurality of teeth and said
plurality of protrusions cooperate with one another to retain said
annular member with said rotor disk.
2. The rotor fan according to claim 1 wherein the plurality of
teeth extend radially inwardly or outwardly according to an
opposite direction of radial extension of said plurality of
protrusions.
3. The rotor fan according to claim 1 wherein each of said
plurality of teeth subtend a clearance between a corresponding one
of said plurality of protrusions, said clearance being parallel to
said central axis of said disk.
4. The rotor fan according to claim 1 wherein said radially inner
portion of said annular member is fastened to said radially inner
portion of said disk with a plurality of spindles running parallel
to the central axis of said disk.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a fan blade mounting
arrangement for a turbojet engine rotor fan.
[0003] More specifically, the invention concerns a turbojet engine
fan rotor comprising a plurality or detachable fan blades affixed
to a disk rim defining a plurality of channels defined along the
periphery thereof, each fan blade including a root mounted in a
channel of the disk and dimensioned and configured in a
corresponding manner. Each fan blade is secured in the channel with
a wedge interposed between the blade root and an axial base surface
of the channel. The mounting arrangement further includes an
annular member resting against the disk having a plurality of
radially extending teeth that cooperate with a plurality of
radially extending protrusions of the disk to prevent axial
displacement of the blades.
[0004] Hereinafter, in reference to a fan rotor of a turbojet
engine, an upstream portion denotes a portion extending in the
direction of the engine fore whereas a downstream portion denotes a
portion extending in the direction of the rearward end of the
engine. A radially inner portion denotes a zone near a central axis
of rotation of the disk and a radially outer zone denotes a portion
radially extended from the central axis of the disk.
[0005] 2. Summary of the Prior Art
[0006] One known mounting arrangement is disclosed in French patent
document 2 681 374 which describes a mounting arrangement for
turbojet engine fan blades. The mounting arrangement includes
scalloped clamps situated upstream and downstream of the disk, and
fitted with orifices adapted to affix two rings mounted on a front
fairing and a compressor drum that cooperate with the ends of the
blade roots in order to secure them in both an axial and radial
fashion. Along the downstream portion of the roots, the fan blades
are fitted with two spoilers that engage the radially inner and
outer sides of a first ring, and further include two spoilers
positioned along the upstream portion of the roots that engage the
radially inner and outer sides of a second ring. This mounting
arrangement requires complex machining of fan blades that are
fitted with two spoilers at their ends, and also renders difficult
and lengthy the replacement of a damaged blade due to the need to
unscrew a plurality of affixation spindles which are positioned in
the orifices of a scalloped flange which is difficult to
access.
SUMMARY OF THE INVENTION
[0007] The objective of the present invention is to provide a
mounting arrangement for a fan rotor such as described above
wherein the blades are secured in a cascaded manner with respect to
their axial displacements.
[0008] This objective is attained by wedges interposed between the
blade root and the corresponding channel and further arranged at
one of their ends with a boss that is interposed between the blade
roots and the annular member. The disk includes along an upstream
portion a plurality of radial protrusions that alternate with the
channels. The annular member defines a plurality of radially
extending teeth along a downstream portion that cooperate with a
plurality of radially extending protrusions of the disk to prevent
axial displacement of the blades. The radially inner portion of the
annular member is fastened to a radially inner portion of the disk
with a plurality of fasteners running parallel to the central axis
of the disk.
[0009] Due to the mounting arrangement, the fan blades are secured
in a significantly improved manner. The fan blades are mounted in
the following manner: first, the fan blade rests on the wedge, then
at least one radial tooth of the annular member cooperates partly
with a disk protrusion to affix the fan blade in place, finally the
plurality of fasteners securing the disk and annular member
cooperate to lock the fan blade in place.
[0010] In case of an axial displacement of a blade, loads are
absorbed simultaneously by the radial disk protrusions and the
fasteners affixing the annular member on the disk. These fasteners
therefore absorb only part of the loads. If the fasteners affixing
the annular member on the disk include spindles, the present
invention requires fewer spindles than used than in the prior art
of the French patent document 2 681 374 A. Lastly, since the radial
protrusions of the disk are without orifices to affix the annular
member, they are able to withstand larger axial loads than the
scalloped clamps of the French patent document 2 681 374 A.
[0011] Advantageously, the radial disk protrusions run radially
outward and the radial teeth run radially inward. Another
embodiment may include the radial protrusions running radially
inward and the radial annular member teeth running radially
outward.
[0012] Advantageously an axial clearance is subtended between the
radial disk protrusions and the radial annular member teeth. This
clearance permits dissipating part of the energy resulting from an
axial displacement of the fan blade retained by the wedge.
[0013] In another embodiment of the invention, the fasteners
affixing the annular member onto the disk comprise a plurality of
spindles running parallel to the central axis of the disk.
[0014] The number of such spindles must be sufficient to retain the
annular member against the disk when a fan blade is displaced
axially. Advantageously, these spindles include a set of bolts and
nuts capable of withstanding the axial and shearing loads.
[0015] The invention and its advantages are elucidated in the
description below of illustrative and non-limiting embodiments, and
in relation to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a cross-section of the mounting arrangement in
accordance with the invention.
[0017] FIG. 2 is a section taken on line II-II in FIG. 1.
[0018] FIG. 3 is a partial isometric perspective view from
downstream to upstream of the outer disk portion comprising a
single wedge and showing the annular member in an unlocked
relationship with the disk.
[0019] FIG. 4 is a view similar to FIG. 3 and depicts the annular
member in a locked relationship with the disk.
[0020] FIG. 5 is a part sectional view of the mounting arrangement
of the present invention.
[0021] FIG. 6 is a perspective view from upstream to downstream of
the disk without the annular member.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] FIGS. 1 and 2 show a fan rotor disk 10 having a central axis
and a rim 12 arranged along a periphery thereof. The rim 12
includes a plurality of channels 14 axially extending along the
central axis of the disk 10 at spaced apart angular intervals.
Arrow F points in the direction from upstream to downstream
portions and denotes the direction of the airflow.
[0023] The root 16 of a fan blade 18 is configured by being axially
inserted into each channel 14. A wedge 20 is interposed between the
blade root 16 and the base of the channel 14, thereby maintaining
the blade root 16 secured against the walls of the corresponding
channel 14.
[0024] Each wedge 20 is fitted with a boss 22 at one of its ends.
Advantageously each boss 22 is configured at the upstream end of
the wedge 20 between the upstream side of the blade root 16 and an
annular member 24 which rests against the upstream side of the disk
10. The annular member 24 includes an inner wall of an annulus
inwardly bounding the airflow duct through the fan.
[0025] At its upstream side and alternating with the channels 14,
the disk 10 comprises a plurality of radial, outwardly extending
protrusions 26. On its downstream side, the annular member 24
defines a plurality of inwardly extending radial teeth 28 that rest
against the radial protrusions 26 of the disk 10.
[0026] In an alternate embodiment, the radial protrusions 26 of the
disk 10 extend radially inward and the radial teeth 28 of the
annular member 24 extend radially outward.
[0027] FIG. 3 shows the mounting arrangement in an unlocked
position wherein the annular member 24 is not secured to the disk
10. In this embodiment, in order to secure the annular member 24
with the disk, the radial teeth 28 of the annular member 24 are
inserted through notches 30 configured between the radial
protrusions 26 of the disk 10 and situated above the bases of the
channels 14.
[0028] Upon rotating the annular member 24 relative to the disk 10
about the central axis of rotation of the disk 10 and by an angle
which is half the angle subtended between two consecutive channels,
the radial teeth 28 move until opposite and downstream of the
radial protrusions 26.
[0029] FIG. 4 shows the annular member 24 in the locked position.
The width of the radial teeth 28 of the annular member 24 may be
dimensioned greater than the radial protrusions 26 of the disk 10
in order that a fraction of each radial tooth 28 axially locks in
position a portion of each fan blade 18.
[0030] The annular member 24 is maintained in position by a simple
bolt/nut system.
[0031] The fasteners of the annular member 24 comprise locking
elements consisting of small spindles fitted with bolts 44 and nuts
46. FIG. 5 shows a bracket 42 which is bolted down by bolts 44 and
nuts 46 that are mounted onto the disk 10. The disk 10 remains
unchanged in its radially inner portion and therefore assumes a
simple geometry in its radially inward portion. The above-mentioned
configuration also applies to the annular member 24.
[0032] The bolted bracket 42 simultaneously maintains the annular
member 24 rotating relative to the disk 10 and secures it axially
in place, entailing a corresponding number of spindles. FIG. 6
shows the disk 10 including along the radially inner portion a
plurality of orifices that maintain the annular member 24 against
the disk 10. Illustratively the affixation of the annular member 24
to the disk is implemented by a plurality of bolts 44 and nuts 46
in a manner to maintain the annular member 24 secured against the
disk 10 even if there is loss of a blade.
[0033] The semi-joint axial latching of the mobile fan blades is
carried out as follows: upon an axial displacement of a fan blade
18, the blade 18 is urged rest against the boss 22 of the wedge 20,
whereby part of the radial teeth 28 of the annular member 24
prevents further movement of the fan blade 18. A clearance 48 is
defined and subtended between the radial teeth 28 of the annular
member 24 and the radial protrusions 26 of the disk for the purpose
of dissipating some of the energy of the fan blade 18, whereupon
the annular member 24 is able to deform before the radial teeth 28
thereby resting against the radial protrusions of the disk 10.
[0034] FIG. 5 shows bracket 42 and the set of fasteners 44, 46 that
cooperate to lock the annular member 24 to the disk 10.
[0035] It will of course be appreciated that the invention is not
confined to the particular embodiment described herein, but is
intended to embrace all possible variations which might be made to
it without departing from either the scope of spirit of the
invention.
* * * * *