U.S. patent application number 11/466994 was filed with the patent office on 2009-05-28 for device for blocking a ring for axially retaining a blade, associated rotor disk and retaining ring, and rotor and aircraft engine comprising them.
This patent application is currently assigned to SNECMA. Invention is credited to Laurent Gilles DEZOUCHE.
Application Number | 20090136349 11/466994 |
Document ID | / |
Family ID | 36390217 |
Filed Date | 2009-05-28 |
United States Patent
Application |
20090136349 |
Kind Code |
A1 |
DEZOUCHE; Laurent Gilles |
May 28, 2009 |
DEVICE FOR BLOCKING A RING FOR AXIALLY RETAINING A BLADE,
ASSOCIATED ROTOR DISK AND RETAINING RING, AND ROTOR AND AIRCRAFT
ENGINE COMPRISING THEM
Abstract
A device for rotationally blocking a retaining ring on a rotor
disk three successive blocking hooks of the disk (10), two cleats
of the retaining ring, arranged on either side of a split in the
retaining ring. The position of the cleats on the retaining ring is
such that, when the retaining ring is in place in a groove situated
in the rotor disk, the two cleats are in respective abutment
against the first and third blocking hooks, and the split is
covered by the second blocking hook.
Inventors: |
DEZOUCHE; Laurent Gilles;
(Coudray Montceau, FR) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
SNECMA
Paris
FR
|
Family ID: |
36390217 |
Appl. No.: |
11/466994 |
Filed: |
August 24, 2006 |
Current U.S.
Class: |
416/219R |
Current CPC
Class: |
F01D 5/3015
20130101 |
Class at
Publication: |
416/219.R |
International
Class: |
F01D 5/30 20060101
F01D005/30 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 31, 2005 |
FR |
0552636 |
Claims
1. A device for rotationally blocking a ring for retaining blades
on a rotor disk of a turbomachine in a substantially axial
direction of said turbomachine, said rotor disk being provided with
hooks spread around its circumference and defining a groove for
accommodating said retaining ring, including in succession a first
blocking hook, a second blocking hook and a third blocking hook,
said second blocking hook being situated between said first and
third blocking hooks, and said retaining ring being provided with a
split and with two cleats arranged on a ring face on either side of
said split, wherein the position of said cleats on said retaining
ring is such that, when said retaining ring is in place in said
groove, said two cleats are in respective abutment against said
first blocking hook and against said third blocking hook, and said
split is covered by said second blocking hook.
2. The rotation-blocking device as claimed in claim 1, wherein:
said first and third blocking hooks are each provided with a check
face on their side which is opposite to the side facing said second
blocking hook, and said cleats of said retaining ring are each
provided with a contact face oriented toward said split, and said
check faces cooperate with said contact faces in order to bring
said cleats into abutment against said first and third blocking
hooks.
3. The blocking device as claimed in claim 2, in which said groove
has two walls, one internal wall which is closer to the rotor disk
and one external wall which is further from the rotor disk, wherein
each check face is situated on the corresponding blocking hook and
extends in the axial direction, starting from a free surface of
said blocking hook and continuing as far as the internal wall of
said groove.
4. The blocking device as claimed in claim 2, wherein said check
faces are oriented in a radial plane of said rotor disk.
5. (canceled)
6. A disk/ring assembly of a turbomachine, comprising a retaining
ring provided with a split, and comprising a rotor disk provided
with hooks spread around its circumference and defining a groove
for accommodating said retaining ring, wherein said rotor disk
comprises a first blocking hook, a second blocking hook and a third
blocking hook in succession, wherein said retaining ring comprises
two cleats arranged on a ring face on either side of said split,
and wherein the position of said cleats on said retaining ring is
such that, when said retaining ring is in place in said groove,
said two cleats are in respective abutment against said first
blocking hook and against said third blocking hook, and said split
is covered by said second blocking hook.
7. The disk/ring assembly as claimed in claim 6, wherein said first
and third blocking hooks are each provided with a check face on
their side which is opposite to the side facing said second
blocking hook, said cleats of said retaining ring are each provided
with a contact face oriented toward said split, and said check
faces cooperate with said contact faces in order to bring said
cleats into abutment against said first and third blocking
hooks.
8. A turbomachine rotor, which comprises a blocking device as
claimed in claim 1.
9. An aircraft engine, which comprises a blocking device as claimed
in claim 1.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the technical field of
rings for axially retaining the blades of a rotor of a
turbomachine, in particular of an aircraft engine.
[0002] It is aimed at a device for rotationally blocking such a
retaining ring.
[0003] It is also aimed at a retaining ring equipped with such a
rotation-blocking device.
[0004] It is additionally aimed at a rotor comprising a retaining
ring equipped with such a rotation-blocking device.
[0005] It is finally aimed at a turbomachine, for example an
aircraft engine, comprising such a retaining ring equipped with
such a rotation-blocking device.
[0006] Throughout the text, the term "axial" refers to the axial
direction of the turbomachine.
DESCRIPTION OF THE PRIOR ART
[0007] It is known that a turbomachine rotor is equipped with a
disk and with blades carried by the disk, and also with a retaining
ring for preventing a displacement of the blades in the axial
direction, as described in document FR 2 729 709-A1.
[0008] FIG. 1 illustrates such a ring for retaining the blades of a
rotor, known from the prior art.
[0009] Referring to FIG. 1, a disk 10 of a rotor comprises a disk
body 11 and teeth 12 which extend radially from the disk body 11
and are spread around the circumference thereof. The space between
two successive teeth 12 forms an axially oriented recess 13. Each
tooth 12 is provided with at least one hook 6 which projects in an
axial direction and which in this tooth defines an individual
groove opening radially inward. In the example illustrated, the
teeth 12 are provided with an upstream hook 6 and with a downstream
hook 6.
[0010] FIG. 2 illustrates a root 14 of a blade 16 inserted into one
such recess 13. The two teeth 12 make it possible to contain this
blade 16 both circumferentially and radially.
[0011] As illustrated in FIG. 2, and in a known manner, a retaining
ring 20 is placed in a discontinuous groove 22 which corresponds to
the succession of the individual grooves. The presence of the
retaining ring 20 in the groove 22 makes it possible to prevent an
axial displacement of the blades 16. To facilitate its installation
in the groove 22, the retaining ring 20 is open by way of a split
24 which separates the two ends or strands 26 of this ring.
[0012] It is generally preferred for the split 24 in the retaining
ring 20 to be situated at the level of one of the teeth 12 and not
between two adjacent teeth 12 so as to prevent the ends of the
retaining ring 20 from coming out of the groove 22. For this
purpose, it is known practice to provide the retaining ring 20 with
a rotation-blocking device which ensures that the split 24 remains
positioned at the level of the one tooth 12, once the retaining
ring 20 has been installed in the groove 22.
[0013] The device for rotationally blocking the retaining ring 20
according to the prior art, illustrated in FIG. 1, comprises:
[0014] two cleats 30 of the retaining ring 20, which are
respectively arranged at the two ends 26 of this ring, on each side
of the split 24, and which each have a contact face 32 directed
toward the split 24, and [0015] a stop-forming hook 60 of one of
the teeth 12, this stop-forming hook 60 having a front face 42 and
two lateral faces 44 which are substantially opposed to one
another, the lateral faces 44 being obtained by machining the
lateral sides of the stop-forming hook 60.
[0016] When the retaining ring 20 is put in place in the groove 22,
each contact face 32 of the respective cleats 30 is in abutment
against one of the lateral faces 44 of the stop-forming hook 60.
Consequently, the split 24 is situated beneath the stop-forming
hook 60 and the retaining ring 20 is prevented from turning in the
groove 22, with the result that the retaining ring 20 cannot
spontaneously come out of the groove 22 during the operation of the
turbomachine. It follows that the blades 16 cannot escape from the
recesses 13 in which their roots 14 are inserted.
[0017] However, the width D of the stop-forming hook 60 is small on
account of this stop-forming hook 60 being machined on its two
lateral sides. Consequently, the split 24 in the retaining ring 20
is covered by the stop-forming hook 60 over a distance which is
equal to the width D of the stop-forming hook 60, and there is a
risk that one of the two ends 26, or the two ends 26, of the
retaining ring 20 might escape from the individual groove of the
tooth 12 having the stop-forming hook 60. This risk is increased
when the split 24 in the retaining ring 20 is oriented obliquely
with respect to the circumferential direction of the retaining ring
20, and not perpendicularly to this direction. Consequently, this
might result in an axial displacement of a blade 14, and
consequently in the loss of this blade 14.
SUMMARY OF THE INVENTION
[0018] The present invention provides a device for rotationally
blocking a ring for retaining the blades of a rotor of a
turbomachine, which overcomes the abovementioned disadvantage
inherent in the rotation-blocking device of the prior art.
[0019] According to a first aspect, the invention relates to a
device for rotationally blocking a ring for retaining blades on a
rotor disk of a turbomachine in a substantially axial direction of
said turbomachine, said rotor disk being provided with hooks spread
around its circumference and defining a groove for accommodating
said retaining ring, and said retaining ring being provided with a
split.
[0020] The blocking device comprises: [0021] in succession a first
blocking hook, a second blocking hook and a third blocking hook of
said rotor disk, and [0022] two cleats of said retaining ring,
arranged on a ring face on either side of said split.
[0023] The position of said cleats on said retaining ring is such
that, when said retaining ring is in place in said groove, said two
cleats are in respective abutment against said first blocking hook
and against said third blocking hook, and said split is covered by
said second blocking hook.
[0024] As will become apparent from the remainder of the
description, the term "blocking hook" covers two functions
performed by one or more of these three hooks: a stop function for
a cleat and a function of covering the split.
[0025] Preferably, said first and third blocking hooks are each
provided with a check face on their side which is opposite to the
side facing said second blocking hook, said cleats of said
retaining ring are each provided with a contact face oriented
toward said split, and said check faces cooperate with said contact
faces in order to bring said cleats into abutment against said
first and third blocking hooks.
[0026] In particular, said groove has two walls, one internal wall
which is closer to the rotor disk and one external wall which is
further from the rotor disk, and each check face is situated on the
corresponding blocking hook and extends in the axial direction,
starting from the free surface of said blocking hook and continuing
as far as the internal wall of said groove.
[0027] According to one variant embodiment, said check faces are
oriented in a radial plane of said rotor disk.
[0028] According to another variant embodiment, said check faces
are oriented in an oblique plane with respect to a radial plane of
said rotor disk.
[0029] According to a second aspect, the invention relates to a
turbomachine rotor disk, this disk being provided with hooks spread
around its circumference and comprising a first blocking hook, a
second blocking hook and a third blocking hook in succession, in
which disk said first and third blocking hooks are each provided
with a check face on their side which is opposite to the side
facing said second blocking hook.
[0030] In a known manner, said hooks define a groove oriented
radially inward and having two walls, one internal wall which is
closer to the rotor disk and one external wall which is further
from the rotor disk. According to the invention, each check face is
situated on the corresponding blocking hook and extends in the
axial direction, starting from the free surface of said blocking
hook and continuing as far as the internal wall of said groove.
[0031] According to one variant embodiment, said check faces are
oriented in a radial plane of said rotor disk.
[0032] According to another variant embodiment, said check faces
are oriented in an oblique plane with respect to a radial plane of
said rotor disk.
[0033] According to a third aspect, the invention relates to a ring
for retaining the blades of a turbomachine rotor, intended to be
combined with a rotor disk according to the first aspect of the
invention, comprising a split and two cleats which are arranged on
a ring face on either side of said split, and in which said cleats
are spaced apart by an angular gap at least equal to three times
the angular pitch separating two successive blades.
[0034] According to a fourth aspect, the invention relates to a
disk/ring assembly,
comprising a retaining ring provided with a split, and comprising a
rotor disk provided with hooks spread around its circumference and
defining a groove for accommodating said retaining ring, wherein
said rotor disk comprises a first blocking hook, a second blocking
hook and a third blocking hook in succession, wherein said
retaining ring comprises two cleats arranged on a ring face on
either side of said split, and wherein the position of said cleats
on said retaining ring is such that, when said retaining ring is in
place in said groove, said two cleats are in respective abutment
against said first blocking hook and against said third blocking
hook, and said split is covered by said second blocking hook.
[0035] Preferably, said first and third blocking hooks are each
provided with a check face on their side which is opposite to the
side facing said second blocking hook, said cleats of said
retaining ring are each provided with a contact face oriented
toward said split, and said check faces cooperate with said contact
faces in order to bring said cleats into abutment against said
first and third blocking hooks.
[0036] According to a fifth aspect, the invention relates to a
turbomachine rotor comprising a blocking device according to the
first aspect of the invention and/or a rotor disk according to the
second aspect of the invention and/or a retaining ring according to
the third aspect of the invention and/or a disk/ring assembly
according to the fourth aspect of the invention.
[0037] According to a sixth aspect, the invention relates to a
turbomachine, for example an aircraft engine, comprising a blocking
device according to the first aspect of the invention and/or a
rotor disk according to the second aspect of the invention and/or a
retaining ring according to the third aspect of the invention
and/or a disk/ring assembly according to the fourth aspect of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] The invention will be better understood on reading the
detailed description below of embodiments of the invention, which
are given by way of illustration and impose no limitation, with
reference to the appended drawings, in which:
[0039] FIG. 1, already described, shows a perspective view of a
portion of a rotor disk adapted for a device for rotationally
blocking a ring for retaining blades, according to the prior
art;
[0040] FIG. 2, already described, shows a perspective view of a
device for rotationally blocking a ring for retaining blades of a
turbomachine rotor, according to the prior art;
[0041] FIG. 3 shows a perspective view of a portion of a rotor disk
adapted for a device for rotationally blocking a ring for retaining
moving blades, according to the invention;
[0042] FIG. 4 shows a perspective view of a device for rotationally
blocking a ring for retaining blades of a turbomachine rotor,
according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] The rotation-blocking device according to the invention,
illustrated in FIGS. 3 and 4, will be described only in terms of
its differences over the rotation-blocking device according to the
prior art, illustrated in FIGS. 1 and 2. In the figures, identical
references denote identical features.
[0044] To simplify the detailed description which follows, the
retaining ring will be simply referred to as "ring" and the first,
second and third blocking hooks will be simply referred to as
"first hook", "second hook" and "third hook", respectively.
[0045] Referring to FIGS. 3 and 4, a disk 10 of a rotor comprises
teeth 12 which extend radially from its circumference and are
spread around this circumference. The space between two successive
teeth 12 forms an axially oriented recess 13 in which is inserted a
root 14 of a blade 16. These two successive teeth 12 have shapes
and dimensions which make it possible to contain, both
circumferentially and radially, the blade 16 installed between them
in the recess 13.
[0046] The teeth 12 have a projecting portion 4 which protrudes
from the disk 10 in the axial direction toward the upstream side
and/or a projecting portion 4 which protrudes from the disk 10 in
the axial direction toward the downstream side. Within each
projecting portion 4 is formed an individual groove which opens
radially inward, the free end of each projecting portion 4 beyond
the individual groove with respect to the disk body 11 forming a
hook 6 oriented radially inward. Each individual groove has two
walls, one internal wall which is closer to the rotor disk 10 and
one external wall which is further from the rotor disk 10.
[0047] The succession of the individual grooves forms a
discontinuous groove 22 in which ring 20 is arranged. The ring 20
in the groove 22 constitutes an axial stop which makes it possible
to prevent an axial displacement of the blades 16. To facilitate
its installation in the groove 22, this ring 20 is open by way of a
split 24 which separates its two ends 26 from one another.
[0048] The ring 20 comprises two cleats 30 positioned on the same
ring face, on the opposite face to the face of the ring which faces
the rotor disk 10, in the example illustrated in FIG. 2.
[0049] Preferably, each cleat 302, 304 is produced in the following
way. Two cuts are made in the ring 20 so as to allow removal of a
ring sector having a given dimension in the circumferential
direction of said ring 20 and the same dimension as the remainder
of the ring 20 in the axial direction thereof. The removed sector
is replaced by a piece having the same dimension in the axial
direction and the same dimension in the circumferential direction,
but having a greater thickness. This piece is fastened to the
remainder of the ring 20 by welding so as to reconstitute a closed
ring 20. The cleat 302, 304 is then machined into said piece having
a greater thickness than the remainder of the ring 20. Such a
procedure makes it possible to carry out precise machining of the
cleats 302, 304, ensuring their dimensions and their position on
the ring 20.
[0050] The split 24 is made in the ring 20 following the production
of the two cleats 30. It is positioned such that the two cleats 30
are arranged toward one of the ends 26 of the ring 20, on either
side of the split 24, at a specified distance from this split.
Preferably, the two cleats 30 are spaced apart by an angular gap at
least equal to three times the angular pitch of the blades 16. This
angular pitch is defined as the angular gap between the center
planes of two successive recesses 13.
[0051] Each cleat 30 comprises a contact face 32 oriented toward
the split 24 in the ring 20.
[0052] Among the hooks 6 there are, in succession, a first hook 62,
a second hook 64 and a third hook 66.
[0053] The second hook 64 has a geometry similar to the geometry of
the hooks 6 of the prior art.
[0054] The first hook 62 and the third hook 66 have a geometry
which is modified in relation to that of the hooks 6. Each of the
first and third hooks 62, 66 has a front face 142 which is the face
of its free surface, and a lateral face 144 which is substantially
perpendicular to the front face 142. The lateral face 144 of the
first hook 62, or of the third hook 66, respectively, extends from
the front face 142 of said hook 62, 66 as far as the internal wall
of the individual groove of said hook 62, 66. Preferably, the
lateral face 144 of the first hook 62 is obtained by a machining
operation on its lateral side which is opposite to its lateral side
which faces the third hook 66. Analogously, the lateral face 144 of
the third hook 66 is obtained by a machining operation on its
lateral side which is opposite to its lateral side which faces the
first hook 62.
[0055] In other words, each of the corresponding teeth 12 is
terminated by a hook 62, 66 which has a lateral face 144 on its
side which is opposite to its side facing the other hook 66, 62,
said lateral face being set back circumferentially.
[0056] In the example illustrated in FIG. 2, the lateral faces 144
are oriented in a radial plane of the rotor disk 10.
[0057] The position of the two cleats 30 on the ring 20 is
established in a suitable manner, preferably depending on the
dimensions and distances of the hooks 62, 64, 66 of the rotor disk
10. This position may be defined by their respective distances with
respect to the respective ends 26 of the ring 20 or by the angular
gap which separates them. For reasons associated with ease of
manufacture, it is preferred, but not necessary, for the two cleats
30 to be arranged symmetrically on either side of the split 24.
[0058] Given a suitable relative position of the two cleats 30 on
the ring 20, when the ring 20 is put in place in the groove 22, the
contact face 32 of one of the cleats 30 is in abutment against the
lateral face 144 of the first hook 62, and the contact face 32 of
the other cleat 30 is in abutment against the lateral face 144 of
the third hook 66. The lateral faces 144 are respective check faces
of the first hook 62 and of the third hook 66, which cooperate with
the respective contact faces 32 of the two cleats 30 of the ring
20. The two ends 26 of the ring 20 and the split 24 are then
situated beneath the second hook 64.
[0059] The ring 20 is thus prevented from turning in the groove 22.
Consequently, the ring 20 cannot escape from the groove 22 during
the operation of the turbomachine. It follows that the blades 16
cannot escape in the axial direction from the recess 13 in which
they are inserted.
[0060] The invention which has just been described therefore makes
it possible to prevent the ring 20 from turning in the groove 22.
It has the advantage that the split 24 in the ring 20 is positioned
beneath a hook and not between two hooks. Furthermore, the split 24
is positioned beneath the second hook 64, which does not have a set
back lateral face, and therefore has a width DD which is not small
as was the possibility with the width D of the hook 60 of the
blocking device of the prior art. Consequently, the risks of the
ends of the ring 20 coming out of the groove 22 are small.
[0061] With the device for rotationally blocking the ring 20
according to the invention, the actual blocking function (by
bringing contact faces 32 of the cleats into abutment against the
check faces 144 of the first and third hooks 62, 66) and the
function of covering the split 24 are not provided by a single disk
hook, as was the case with the blocking device of the prior
art.
[0062] The invention is not limited to the embodiment which has
just been described. In the example illustrated in FIG. 4, the
split 24 is perpendicular to the circumferential direction of the
ring 20, but it could be oblique without departing from the scope
of the invention.
[0063] In the example illustrated in FIGS. 3 and 4, the check faces
are oriented in a radial direction of the rotor disk 10, but they
could be oriented in an oblique direction with respect to a radial
direction of the rotor disk 10, without departing from the scope of
the invention.
[0064] In the example illustrated in FIGS. 3 and 4, the recesses 13
in which are inserted the roots 14 of the blades 16 are oriented
axially, but the invention equally applies to configurations in
which the direction of the recesses forms an angle with the axial
direction of the turbomachine.
* * * * *