U.S. patent application number 10/891194 was filed with the patent office on 2005-04-14 for perfected device for setting synchronizing rings of a turbojet compressor.
This patent application is currently assigned to SNECMA MOTEURS. Invention is credited to Jolibois, Gerard, Plona, Daniel.
Application Number | 20050079046 10/891194 |
Document ID | / |
Family ID | 33523038 |
Filed Date | 2005-04-14 |
United States Patent
Application |
20050079046 |
Kind Code |
A1 |
Jolibois, Gerard ; et
al. |
April 14, 2005 |
Perfected device for setting synchronizing rings of a turbojet
compressor
Abstract
A device is dedicated to setting one or more pivoting axial flow
synchronizing rings (R), comprising a drive mechanism (4-6)
intended to rotate their rotary spindle (3) so as to set them
angularly depending on angular position data supplied by a means of
control. These means of control comprise firstly means of
illumination (8, 10) designed to supply light to an illumination
zone (11), secondly an encoder element (12) attached to the spindle
of the synchronizing ring (R) in the illumination zone (11) and
designed to interact with the illumination light in order to
generate optical signals representing the angular position of the
synchronizing ring, thirdly means (13a) designed to collect the
optical signals and fourthly means of processing (7) designed to
determine angular position data based on the optical signals
collected.
Inventors: |
Jolibois, Gerard; (Le
Chatelet En Brie, FR) ; Plona, Daniel; (Vulaines Sur
Seine, FR) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
SNECMA MOTEURS
Paris
FR
|
Family ID: |
33523038 |
Appl. No.: |
10/891194 |
Filed: |
July 15, 2004 |
Current U.S.
Class: |
415/13 |
Current CPC
Class: |
F01D 17/162 20130101;
F04D 29/563 20130101 |
Class at
Publication: |
415/013 |
International
Class: |
F01D 017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2003 |
FR |
03 09453 |
Claims
1. Device for setting pivoting axial flow synchronizing ring(s) (R)
for a turbojet compressor (CHP), comprising a drive mechanism (4-6)
suitable for driving in rotation at least one synchronizing ring
(R) spindle (3) so as to set it angularly depending on position
data supplied by means of control (7-26), characterised in that
said means of control comprise means of illumination (8, 10)
capable of supplying light to the illumination zone (11), an
encoder element (12) attached to the synchronizing ring spindle (3)
in said illumination zone and designed in such a way as to interact
with said light to generate optical signals representing the
angular position of said synchronizing ring (R), means of
collection (13) of said optical signals and means of processing (7)
designed to determine angular position data based on said optical
signals collected.
2. Device according to claim 1, characterised in that said encoder
element (12) is implemented in the form of at least one encoder
wheel portion having at least one scale (15) configured in order to
permit the generation of variable optical signals depending on its
position in said illumination zone (11).
3. Device according to any one of claim 1 and 2, characterised in
that said light source (8, 10) comprises at least one optical fibre
(10) having an extremity configured so as to light up said
illumination zone (11) over a surface of selected dimensions.
4. Device according to any one of claims 2 and 3, characterised in
that said scale (15) comprises at least one slot (17, 18)
configured so as to transmit the light differently depending on the
angular position of said encoder element (12).
5. Device according to claim 4, characterised in that said slot
(17) has a progressive opening.
6. Device according to claim 4, characterised in that said scale
(15) comprises a plurality of slots (18) of various shapes and/or
spaced from one another at a variable distance.
7. Device according to any one of claims 2 and 3, characterised in
that said scale is transparent and consists of at least one zone
equipped with markings (21).
8. Device according to claim 7, characterised in that it comprises
a transparent scanning reticle (25) interposed between the
illumination light and said encoder element (12) and in that said
means of collection (13) comprise photodetectors (13b) positioned
facing said scale (15) on the side opposite said illumination zone
(11) and capable of supplying electrical signals representing
optical signals resulting from the interaction between the
illumination light, said scanning reticle (25) and said markings
(21).
9. Device according to any one of claims 4 to 7, characterised in
that said means of collection (13) comprise photodetectors (13b)
positioned facing said scale (15) on the side opposite said
illumination zone (11) and capable of supplying electrical signals
representing optical signals transmitted to the scale.
10. Device according to any one of claims 4 to 7, characterised in
that said means of collection (13) comprise at least one optical
fibre (13a) having an extremity configured so as to collect said
optical signals transmitted to said scale (15).
11. Device according to any one of claims 2 and 3, characterised in
that said scale (15) comprises at least one reflecting element (16)
configured in such a way as to reflect said light differently
according to the angular position of said encoder element (12).
12. Device according to claim 11, characterised in that it
comprises a transparent scanning reticle interposed between said
illumination light and said encoder element (12) and defining a
transparent phase grating, whereby said reflecting element
comprises markings and whereby said means of collection (13)
comprise photodetectors positioned upstream of said scanning
reticle and capable of supplying electrical signals representing
optical signals resulting from the interaction between the
illumination light, said scanning reticle and said markings.
13. Device according to claim 11, characterised in that said means
of collection (13) comprise at least one optical fibre (13a) having
an extremity configured so as to collect said optical signals
reflected to said scale (15).
14. Device according to any one of claims 1 to 13, characterised in
that one section at least of the encoder element (12), one section
of said light source (10) and one section at least of said means of
collection (13a, 13b) are accommodated in a chamber (14) sealed
against light.
15. Device according to any one of claims 1 to 14, characterised in
that said means of processing (7) is accommodated in a casing (9)
remote from said synchronizing ring (R).
16. Device according to any one of the above claims, characterised
in that said drive mechanism (4-6) comprises a ring (5) attached by
a plurality of links (4) to a plurality of synchronizing rings (R)
and a ram (6) capable of adjusting said ring (5) so as to set said
plurality of synchronizing rings (R) in angular positions selected
according to said angular position data determined by said means of
processing (7).
Description
[0001] The invention relates to the field of turbojet compressors
and more particularly that of setting pivoting axial flow
synchronizing rings of these compressors.
[0002] As the person skilled in the art is aware, in an axial flow
turbojet the gases are compressed prior to combustion by a
compressor consisting of several stages. Each stage is composed of
a rotor vane wheel intended to accelerate the axial flow and a
guide vane ring intended to produce the pressure increase. In order
to optimise and adapt the operation of the compressor, a guide
capability or limited "setting" of the aerodynamic profile, which
is controlled by regulating the engine, is provided for the guide
vanes (synchronizing rings).
[0003] The synchronizing rings are generally adjusted by means of a
setting device comprising a drive mechanism attached to their
rotary spindles (also called "vane tail spindles"). More precisely,
the setting device comprises means of control designed to determine
the angular position of one of the synchronizing rings and to
supply the drive mechanism with instructions consisting of angular
position data so that it places the synchronizing rings concerned
in selected angular positions.
[0004] So that such guiding is at the optimum, it is therefore
essential that the angular positioning is precisely determined.
However, due to the presence of high temperatures near the
synchronizing rings, the angular position is measured remotely,
preferably near the control ram. This measurement is thus distorted
by the presence of high vibration, thermal expansion and by play in
the mechanical linkage.
[0005] Therefore, the object of the invention is to remedy all or
some of the aforementioned problems.
[0006] For this purpose, a device is proposed which is dedicated to
setting one or more pivoting axial flow synchronizing rings
comprising a drive mechanism intended to rotate their rotary
spindles in order to set them angularly depending on the position
data supplied by the means of control.
[0007] This device is characterised by the fact that its means of
control comprise firstly means of illumination designed to supply
light to an illumination zone, secondly an encoder element attached
to the spindle of the synchronizing ring in the illumination zone
and designed to interact with the illumination light in order to
generate optical signals representing the angular position of the
synchronizing ring, thirdly means designed to collect the optical
signals and fourthly means of processing designed to determine
angular position data based on the optical signals collected.
[0008] Thanks to the use of optical means of detection, the angular
position is measured directly on the spindle of the synchronizing
ring. The measurement no longer being distorted by cinematic play,
thermal expansion or vibration, its precision is therefore
substantially improved.
[0009] Preferably, the encoder element is implemented in the form
of an encoder wheel (portion) having at least one scale configured
in order to permit the generation of variable optical signals
depending on its position within the illumination zone.
[0010] In addition, the light source preferably comprises at least
one optical fibre having an extremity (possibly combined with means
of optical conversion) configured so as to light up the
illumination zone over a surface of selected dimensions.
[0011] The invention can be implemented in two alternative
embodiments, according to which the optical signals are obtained
either by transmission or by reflection.
[0012] The first category (concerning transmission) consists of at
least two variants.
[0013] A first variant relates to the encoder elements comprising a
scale having at least one slot configured so as to transmit the
light differently depending on the angular position of the encoder
element. Only one slot with progressive opening or a plurality of
slots of various shapes and/or spaced from one another at a
variable distance are provided, for example.
[0014] A second variant relates to the encoder elements comprising
a transparent scale consisting of at least one zone equipped with
markings. In this case, for example, a transparent scanning reticle
can be interposed between the illumination light and the encoder
element and means of collection comprising photodetectors
positioned facing the scale on the side opposite the illumination
zone and designed to supply electrical signals representing optical
signals resulting from the interaction between the illumination
light, the scanning reticle and the markings.
[0015] Alternatively, the means of collection in these two variants
can comprise photodetectors positioned facing the scale on the side
opposite the illumination zone and designed to supply electrical
signals representing optical signals transmitted to the scale. In
another variant, the means of collection can comprise one or more
optical fibres having one extremity (possibly combined with means
of optical conversion) configured in order to collect the optical
signals transmitted to the scale.
[0016] In the second category, the scale of the encoder element
comprises at least one reflecting element configured so as to
reflect the light differently according to the angular position of
the encoder element.
[0017] In this case, firstly a transparent scanning reticle
interposed between the illumination light and the encoder element
and defining a transparent phase grating, secondly a reflecting
element comprising markings and thirdly means of collection
comprising photodetectors positioned upstream of the scanning
reticle and designed to supply electrical signals representing
optical signals resulting from the interaction between the
illumination light, the scanning reticle and the markings can be
provided, for example.
[0018] Alternatively, the means of collection can comprise at least
one optical fibre having an extremity configured so as to collect
the optical signals reflected to the scale.
[0019] According to another feature of the invention, one section
at least of the encoder element, one section of the light source
and one section at least of the means of collection are
accommodated in a chamber sealed against light so that the
measurements are not distorted by parasitic light.
[0020] In addition, the means of processing are preferably
accommodated in a housing remote from the synchronizing ring so
that they are not exposed to high temperature.
[0021] Other features and advantages of the invention will become
apparent after studying the detailed description below and the
accompanying drawings wherein:
[0022] FIG. 1 is a schematic, median transversal sectional view of
a high pressure compressor of a turbojet,
[0023] FIG. 2 schematically illustrates in a side view an exemplary
embodiment of a setting device according to the invention,
[0024] FIG. 3 is a plan view schematically illustrating the
position of the encoder wheel of the setting device in FIG. 2,
[0025] FIG. 4 schematically illustrates a first exemplary
embodiment of the means of detection for the setting device in a
transversal sectional view following lines IV-IV in FIG. 2,
[0026] FIG. 5 schematically illustrates a second exemplary
embodiment of the means of detection for the setting device in a
transversal sectional view,
[0027] FIG. 6 schematically illustrates a third exemplary
embodiment of the means of detection for the setting device in a
transversal sectional view,
[0028] FIG. 7 is a plan view schematically illustrating an encoder
wheel, which can be used in the means of detection in FIGS. 5 and
6,
[0029] FIG. 8 is a plan view schematically illustrating another
encoder wheel, which can be used in the means of detection in FIGS.
5 and 6,
[0030] FIG. 9 schematically illustrates a fourth exemplary
embodiment of the means of detection for the setting device in a
transversal sectional view and
[0031] FIG. 10 schematically illustrates a fifth exemplary
embodiment of the means of detection for the setting device in a
transversal sectional view.
[0032] The accompanying drawings will not only serve to complete
the invention but also possibly contribute to its definition.
[0033] The invention relates to a device for setting the pivoting
axial flow synchronizing ring(s) of a turbojet compressor.
[0034] Firstly, one should refer to FIG. 1 to see in detail the
location of a setting device according to the invention.
[0035] In an axial flow turbojet, a compressor, for example, a
high-pressure compressor CHP as illustrated in FIG. 1 comprising
several stages, is designed to compress the gases prior to
combustion in the combustion chamber CC. Each stage is composed of
a rotor vane wheel intended to accelerate the axial flow, the rings
carrying vanes A, and a guide vane ring called synchronizing ring R
intended to produce the pressure increase.
[0036] Vanes A of the rotor wheels and the guide vanes of the
synchronizing rings R are accommodated in a chamber 1 delimited by
a casing 2. These synchronizing rings R are mounted for rotation on
the casing 2 of the compressor CHP so that they can be adjusted (or
directed) into positions for optimum guiding of the axial flow by
setting devices, partially illustrated. More precisely, although
this does not appear on the drawing, several synchronizing rings R
are generally installed between two stages of vanes A and their
angular positions are controlled by the same setting device.
[0037] As this is best illustrated in FIG. 2, each synchronizing
ring R comprises a rotary spindle 3, which is attached to a link 4
fitted to a drive wheel 5. Each wheel 5 is itself attached to a ram
6 having variable travel. In addition, all synchronizing rings R
installed between two stages of vanes A are attached to a same
wheel 5. They thus constitute stages as it were. The displacement
of a wheel 5 by way of the associated ram 6 therefore causes the
angular displacement of all the synchronizing rings R of a stage.
The amount of travel of a ram 6 and therefore the angular
adjustment position of the synchronizing rings R of a stage is
determined every time by a processing module 7 depending on the
required performance of the turbojet and on angular position
measurements made by a means of detection on one at least of the
synchronizing rings R of a stage as will be seen later.
[0038] The links 4 attached to the synchronizing rings R of a same
stage, the associated wheel 5 and the ram 6 constitute the drive
mechanism of a setting device, while the means of detection and the
processing module 7 constitute the means of control for this
setting device.
[0039] According to the invention, the means of detection of the
setting device comprise firstly a light source 8, secondly means of
directing the light 10 designed to supply light to an illumination
zone 11, thirdly an encoder element 12 attached to the spindle 3 of
one of the synchronizing rings R in the illumination zone 11 and
designed to interact with the illumination light to generate
optical signals representing the angular position of the
synchronizing ring 5, and fourthly means 13 designed to collect the
optical signals to supply these to the processing module 7.
[0040] Preferably, the light source 8 is located at a distance in a
casing 9, which also accommodates the processing module 7. In
addition, the means of directing the light 10 are preferably
implemented in the form of one or more optical fibres.
[0041] Depending on the method of detection used, it is preferable
that one section at least of the encoder element 12, the downstream
extremity of the optical fibre 10 and one section at least of the
means of collection 13 are accommodated in a chamber 14 sealed
against light. Thus, the optical measurements are not distorted by
parasitic light or by possible dust or any, in particular greasy,
residues present in the turbojet.
[0042] As this is best illustrated in FIG. 3 the encoder element 12
is preferably provided in the form of an encoder wheel and more
preferably still in the form of an encoder wheel portion. This
comprises at least one scale 15 configured so as to permit the
generation of variable optical signals depending on its position
within the illumination zone 11 and therefore depending on the
angular position of the synchronizing ring R to the spindle 3,
which is attached to it.
[0043] Detection can be carried out either by reflection or
transmission.
[0044] An exemplary embodiment configured for detection by
reflection is illustrated in FIG. 4. Here the scale 15 of the
encoder wheel portion 12 comprises several reflecting elements 16,
the dimensions and/or patterns of which differ so that the
intensity of reflected light varies according to its angular
position. These 3D-type reflecting elements 16 can be implemented
by selective deposition or engraving or again by photolithography
or any other known technique.
[0045] The illumination light is supplied to the illumination zone
11 by the downstream extremity of the source optical fibre 10, then
reflected by the reflecting elements 16 and finally collected by
the upstream extremity of one or more collection optical fibres
13a. This (these) collection optical fibre(s) then direct the
reflected and collected light (or collected optical signals) to the
casing 9 where they (it) undergo(es) an intensity measurement, for
example using a photoelectric converter of the processing module 7.
The processing module 7 is then designed in such a way as to
convert the luminous intensity measured into a measurement of
angular position. For this purpose, it can comprise, in a memory, a
table co-relating luminous intensities to angular positions, for
example. Alternatively, it can comprise a circuit or programme
designed to calculate the position depending on the intensity
measured.
[0046] Once the angular position has been measured, the processing
module 7 can compare this to the optimum angular position, which
the synchronizing rings R of the stage that it controls must
assume, so that the turbojet offers selected performances. The
optimum angular position can either be determined by the processing
module 7 depending on external instructions, or supplied to the
processing module 7 by an external control module.
[0047] If the comparison indicates that the synchronizing rings
must be re-adjusted, the processing module 7 determines new angular
position data, which it transmits to the ram 6 so that its travel
is modulated as a consequence.
[0048] As this is schematically illustrated, the downstream
extremity of the source optical fibre 10 can be configured in order
to light up the illumination zone 11 over a surface of selected
dimensions and the upstream extremity of the collection fibre
optical 13a can be configured in order to collect the light
reflected over a surface of selected dimensions. But, alternatively
or additionally, means of optical conversion, for example, a
reticle or a condenser lens, can be provided between an optical
fibre extremity 10, 13a and the scale 15.
[0049] Instead of using reflecting elements in the scale 15, the
latter can be treated in such a way as to present a variable
reflection factor, progressing from one of its extremities to the
other, for example. In a general way, any means of reflection
conferring variable reflectivity on the scale 15 can be
envisaged.
[0050] In addition, instead of using one or more collection optical
fibres 13a, photodetectors for example of the CCD type (for
coupling charge devices) could be used.
[0051] Exemplary embodiments configured for detection by
transmission are illustrated in FIGS. 5 to 10.
[0052] In the example illustrated in FIG. 5, the scale 15 of the
encoder wheel portion 12 comprises at least one opening or slot 17
configured in order to let a variable quantity of light pass
depending on the angular position of the encoder element. For this
purpose, the slot 17 has a progressive opening as illustrated in
FIG. 7, for example.
[0053] But as illustrated in FIG. 8 the scale 15 could comprise
several slots 18 of variable shapes and/or spaced from one another
at a variable distance. Other embodiments could also be
envisaged.
[0054] To collect the light having crossed the scale 15 through its
slot or slots 17 or 18, two solutions can be envisaged.
[0055] A first solution illustrated in FIG. 5 consists in placing a
photoelectric conversion module 13b (or any other means enabling
photons to be converted into a measurable physical value) under the
encoder wheel portion 12. This conversion module 13b, which
therefore directly collects and converts the photons, is attached
to the chamber 14 by way of fixing mounts 19, for example. The
result of the conversion is transmitted by a cable 20 to the
processing module 7 in order to serve elaboration of the new
angular position data.
[0056] A second solution illustrated in FIG. 6 consists in placing
one or more collection optical fibres 13a of the type described
above with reference to FIG. 4 under the encoder wheel portion 12.
The light (or optical signals collected), which has crossed the
scale 15 through its slot or slots 17 or 18 (illustrated in FIGS. 7
and 8) is therefore collected by the upstream extremity of the
collection optical fibre 13a, which directs it to the casing 9
where they (it) undergo(es) an intensity measurement by way of a
photoelectric converter of the processing module 7, for example.
The processing module 7 is designed so as to convert the luminous
intensity measured into a measurement of angular position. The
result of the conversion then serves elaboration of the new angular
position data.
[0057] As illustrated in FIG. 5, the slot(s) 17 or 18 formed in the
scale 15 can have any type of shape and any type of spacing since
they (it) enable(s) the luminous intensity collected to be varied
depending on the position of the encoder wheel portion 12.
[0058] In addition, as indicated above, the downstream and upstream
extremities of the source 10 and collection 13a optical fibres can
be configured in order to supply or collect the illumination or
reflected light over surfaces of selected dimensions. But,
alternatively or additionally, means of optical conversion such as
a reticle or a condenser lens, for example, can also be provided
between one optical fibre extremity 10, 13a and the scale 15.
[0059] Instead of transmitting the illumination light through
slot(s) 17 or 18 this can be transmitted via materials having
variable reflectivity provided or otherwise with markings (or
marks).
[0060] For example, the scale 15 of the encoder wheel portion 12
can be made of a transparent material with a variable transmission
factor. For this purpose, the scale 15 can be treated so as to
provide a transmission factor crossing from one of its extremities
to the other. Purely, as an example, a glass-type material of
variable thickness can be self-coloured up to a certain degree. In
this case, collection can be effected either by means of one or
more collection optical fibres 13a or by means of a photoelectric
conversion module 13b as described above.
[0061] Alternatively, as illustrated in FIG. 9, markings (or marks)
21 acting either as local reflection means (in this case the
material interposed between adjacent markings is transparent) or as
local transmission means (in this case the material interposed
between adjacent markings is absorbent) can be provided level with
the scale 15. These markings can be formed by sand-blasting, laser
processing, chemical etching or by any other known marking
technique. The markings 21 can have variable shapes and/or can be
spaced from one another at a variable distance.
[0062] As illustrated, collection can be effected using a
photoelectric conversion module 13b (or any other means enabling
photons to be converted to a measurable physical value) placed
under the encoder wheel portion 12. This conversion module 13b,
which therefore here directly collects and converts the photons is
attached to the chamber 14, for example, using fixing mounts 19.
The result of the conversion is transmitted by a cable 20 to the
processing module 7, in order to serve elaboration of the new
angular position data.
[0063] But, as in the above exemplary embodiments, the transmitted
light could be collected with one or more optical fibres 13a,
possibly combined with a means of optical conversion.
[0064] Alternatively, as illustrated in FIG. 10, markings (or
marks) 21 constituting a graduated wide grating (that is to say
substantially above the wavelength of the light) are made level
with the scale 15 and upstream of the encoder wheel portion 12, a
condenser lens 22 attached to the chamber 14 by fixing mounts 23
followed by a scanning reticle 24 likewise attached to the chamber
14 by fixing mounts 25 and defining a graduated narrow grating 26
is provided. When the illumination light diffracted by the scanning
reticle 24 meets the wide grating 21, the diffracted beam
components practically coincide so that a kind of light projection
of the graduated structure 21 is obtained downstream of the encoder
wheel portion 12.
[0065] Any movement of the encoder wheel portion 12 in relation to
the scanning reticle 23 causes shadow/light modulations, which can
be detected by a photoelectric conversion module 13b of the
multi-element type, placed under said encoder wheel portion 12.
This conversion module 13b, which therefore directly collects and
converts the photons is attached to the chamber 14 by means of
fixing mounts 19, for example. The result of the conversion is
transmitted by a cable 20 to the processing module 7 in order to
serve elaboration of the new angular position data.
[0066] Detection of a similar type can also be envisaged in the
case of operation by reflection. In this case, a scanning reticle
defining a transparent phase grating, interposed between the
illumination light and the encoder wheel portion 12, the scale 15
of which comprises a phase grating of the Diadur.RTM. type, and a
photoelectric conversion module 13b of the multi-element type
positioned facing the scale 15 on the side opposite the
illumination zone 11 and designed to supply electrical signals
representing optical signals resulting from interaction between the
illumination light, scanning reticle and the markings, is provided.
This type of detector called "diffraction and interference
detector" is also marketed by the Heidenhain Company.
[0067] In the exemplary embodiments described, the angular position
measurement can be of the absolute type or the relative type. In
the case of relative measurement, an absolute reference can be
provided on the encoder wheel 12 as well as on the possible
scanning reticles 24 and preferably a zero measurement is carried
out whenever the turbojet is stopped.
[0068] The invention is not limited to the exemplary embodiments of
the setting device described above purely by way of example, but it
encompasses all the alternatives, which the person skilled in the
art could envisage in connection with the claims below:
* * * * *