EP3502483B1

EP3502483B1 - Supporting a turbomachine synchronising ring by vane levers

Info

Publication number: EP3502483B1
Application number: EP17208572.2A
Authority: EP
Inventors: Gasper CAFUTA; Opara TOMAZ
Original assignee: Cimos dd
Current assignee: Cimos dd
Priority date: 2017-12-19
Filing date: 2017-12-19
Publication date: 2020-09-02
Anticipated expiration: 2037-12-19
Also published as: EP3502483A1

Description

The invention relates to a turbomachine fluid guiding stator device. The invention also relates to a turbomachine comprising at least one such device. More particularly, the invention relates to a fluid guiding stator device comprising a stationary blade assembly with a variable cross-section and a turbomachine comprising at least one such device.
Throughout the text, "turbomachine" is intended to mean, as is usual, any machine through which a fluid passes, and which receives (turbine) and/or generates (compressor, blower, fan, pumps) fluidic energy, comprising a stator and at least one wheel mounted to rotate with respect to the stator about a main axis of the machine. Each wheel is provided with a blade assembly (assembly of a plurality of blades), named mobile blade assembly, and is in fluid communication with a fluid guiding stator device comprising a blade assembly, named stationary blade assembly, fixedly attached to the stator. Depending upon the applications, a turbomachine may be: axial or radial; with incompressible fluid (liquid) or with compressible fluid (air, gas, vapours ...).
In particular, a turbine is a turbomachine receiving fluidic energy comprising a stator and at least one wheel mounted to rotate with respect to the stator about a main axis of the turbine. Each wheel of a turbine is provided with a mobile blade assembly supplied with fluid from a fluid guiding stator device, named distributor, comprising a stationary blade assembly fixedly attached to the stator. Similarly, a compressor is a turbomachine generating fluidic energy comprising a stator and at least one wheel mounted to rotate with respect to the stator about a main axis of the compressor. Each wheel of the compressor is provided with a mobile blade assembly delivering the fluid into a fluid guiding stator device, named diffusor, comprising a stationary blade assembly fixedly attached to the stator. A turbomachine can also be a turbocompressor, i.e. a machine which combines the functions of a turbine and compressor and thus has a distributor for the turbine and a diffusor for the compressor.
Therefore, a turbomachine fluid guiding stator device is a device adapted to guide a flow of fluid, in particular to a turbine or even for guiding a flow of fluid from a compressor.
Some fluid guiding devices comprise a stationary blade assembly having a variable cross-section, i.e. a blade assembly comprising a plurality of blades interposed between two coaxial rings along a main axis defining a passage, named fluid passage:

the blades of said plurality of blades being arranged so as to form, in the fluid passage between every two blades and between the rings of the blade assembly, a plurality of channels,
each blade of said plurality of blades being mounted to rotate on an axis of rotation secant to the coaxial rings, such that a modification of the angular position of the blade results in a modification of the geometric characteristics of each channel delimited by this blade.

Furthermore, a control mechanism is provided to modify the angular position of the blades.
Such a guide stator device with a stationary blade assembly having a variable cross-section is adapted to adjust a flow rate and a direction of a flow of fluid passing through said fluid passage depending upon operating conditions of the turbomachine, e.g. based on the state of the turbomachine.
Numerous mechanisms are known for controlling the angular position of the blades of a stationary blade assembly having a variable cross-section of a turbomachine fluid guiding stator device. In particular, such a known mechanism for controlling the angular position of blades can comprise:

a plurality of levers, at least some of the levers of said plurality of levers - in particular the set of levers of said plurality of levers - being rotationally coupled to at least some of the blades of said plurality of blades,
a ring for controlling the angular position of the blades of the stationary blade assembly, coaxial with the two rings of the stationary blade assembly and being able to be rotationally driven about the main axis with respect to the two rings of the stationary blade assembly, the control ring co-operating, in rotation, with at least one lever of said plurality of levers.

Rotationally driving the control ring about the main axis thus allows the levers of said plurality of levers to be rotationally guided so as to modify the angular position of the blades of the stationary blade assembly.
More particularly, the control ring can have a plurality of radial recesses adapted to receive said plurality of levers, each lever of said plurality of levers having a proximal end rotationally coupled to a blade of said plurality of blades and a distal end, named head, arranged in a recess in the control ring.
Furthermore, the angular displacement of the blades of the stationary blade assembly requires the control ring to be held axially and radially. Different solutions permitting such a holding arrangement are known.
For example, EP 2 239 425 describes, in a first embodiment, holding the control ring axially and radially by way of pins mounted on a ring of the stationary blade assembly facing the control ring, and by way of bosses formed on this ring of the stationary blade assembly. In particular, each pin comprises an arm and shoulders at one end of the arm and protruding from the arm. The control ring is held axially by the pins between shoulders of each pin and a boss arranged around the arm of this pin, and is held radially by the arm of each pin. In another embodiment described in EP 2 239 425 , the control ring is held axially and radially by protrusions formed on the control ring and extending towards and away from a ring of the stationary blade assembly facing the control ring, and by pins mounted on this ring of the stationary blade assembly. The process of axially and radially holding the control ring described in EP 2 239 425 thus requires the addition of supplementary parts (pins) to the turbomachine fluid guiding stator device and the adaption of either the structure of the control ring (protrusions of the control ring) or the structure of the ring of the stationary blade assembly facing the control ring (bosses).
Furthermore, US 2002/0098081 describes a control ring held axially and radially by levers rotationally coupled to blades of the stationary blade assembly and by axial projecting noses of the control ring placed against a peripheral crown-shape recess of a ring of the stationary blade assembly facing the control ring. More particularly, the control ring has a plurality of axial recesses formed in the thickness of the control ring and each lever has a distal end arranged in a recess in the control ring so as to axially hold the control ring. The axial and radial holding of the control ring described in US 2002/0098081 thus requires the adaption of the structure of the control ring (recesses in the thickness of the control ring and projecting noses) and the structure of the ring of the stationary blade assembly facing the control ring (crown-shape recess).
EP 1 357 255 A1 discloses a variable vane assembly wherein a control ring is guided both axially and radially by lever heads.
Therefore, the known ways of axially and radially holding the control ring require the structure of the control ring and/or of the stationary blade assembly to be made more complex and/or require supplementary parts to be added to the guide stator device. The design and manufacture of guide devices comprising such arrangements for holding the control ring are thus relatively complex. Furthermore, the addition of supplementary parts necessarily involves an increase in the weight of the guide stator device and can lead to a higher breakdown risk.
The invention aims to overcome these disadvantages.
The invention thus aims to propose a turbomachine fluid guiding stator device comprising a mechanism which is reliable, simple and inexpensive for controlling the angular position of blades of a stationary blade assembly with a variable cross-section.
The invention aims in particular to propose such a mechanism comprising a control ring which is axially held in a simple and reliable manner. The invention likewise aims to propose such a mechanism comprising a control ring which is radially held in a simple and reliable manner.
The invention aims in particular to propose an arrangement for axially holding the control ring allowing simple design and manufacturing of the mechanism for controlling the angular position of the blades of a turbomachine stationary blade assembly with a variable cross-section. The invention likewise aims to propose an arrangement for radially holding the control ring allowing simple design and manufacturing of the mechanism for controlling the angular position of the blades of a turbomachine stationary blade assembly with a variable cross-section.
The invention also aims to reduce the number of parts of a turbomachine fluid guiding stator device allowing the control ring to be held axially and radially.
The invention thus likewise aims to propose an arrangement for axially and radially holding the control ring allowing the weight of the turbomachine fluid guiding stator device to be reduced.
The invention likewise aims to propose a turbomachine having the same advantages.
To this end, the invention relates to a turbomachine fluid guiding stator device according to claim 1.
More particularly, each driving lever is driven by said control ring. The control ring can be driven by an arm, named driving arm, which can be coupled to the two rings of the stationary blade assembly. Moreover, said driving arm is driven by a motor for controlling the blades of the stationary blade assembly.
Furthermore, the control ring is axially held by said at least two axial holding levers - in particular by the set of levers of said plurality of levers - in any rotational position of the control ring about the main axis with respect to the stationary blade assembly.
Therefore, in a guide stator device in accordance with the invention, the axial holding of the control ring does not require any additional part for the guide stator device other than the levers of the mechanism for controlling the angular position of the blades of the stationary blade assembly.
Axially holding the control ring in accordance with the invention allows the design and manufacture of a fluid guiding stator device in accordance with the invention to be facilitated. In fact, no additional part needs to be added during the manufacturing of the guide stator device in order to allow the control ring to be axially held. Furthermore, the structure of the control ring does not need to be modified to form an axial stop against a ring of the stationary blade assembly. Therefore, a control mechanism in accordance with the invention permits the use of a control ring which can be obtained by stamping, by moulding, or even by folding and/or bending by plastic deformation of a rigid wire, in particular a metal wire.
Furthermore, the levers - in particular the axial holding levers - of the control mechanism can be manufactured by lost-wax moulding (in particular investment casting), injection moulding of metal powder, stamping and by cold-forming, additive manufacturing such as metal additive manufacturing or by any other suitable, simple, and inexpensive manufacturing method.
Therefore, the invention, for the first time, allows a mechanism for controlling the angular position of the blades which is simple, reliable and inexpensive to be obtained.
Preferably, a turbomachine fluid guiding stator device comprises at least three axial holding levers, in particular at least four. Advantageously, each lever coupled to the blades of the stationary blade assembly - preferably each lever of said plurality of levers - is an axial holding lever.
Preferably, each axial holding lever is a driving lever coupled to a driven blade of the stationary blade assembly.
In some embodiments, each blade of the stationary blade assembly is arranged in a passage, named fluid passage, delimited by faces, named guiding faces, facing each other of the two coaxial rings of the stationary blade assembly. Furthermore, the blades of said plurality of blades are arranged so as to form a plurality of channels in the fluid passage between every two blades and between the rings of the stationary blade assembly. Each blade of a stationary blade assembly in accordance with the invention is rotationally guided between the two guiding faces on a theoretical axis of rotation, named pivoting axis, secant with the guiding faces, in particular normal to the two guiding faces (orthogonal to the two guiding faces when these are flat; orthogonal to the tangent to each guiding face when these are coaxial and rotationally cylindrical about the main axis of the turbomachine). Therefore, a modification of the angular position of a blade results in a modification of the geometric characteristics of each channel delimited by this blade.
Preferably, each blade of the stationary blade assembly is a driven blade rotationally coupled to a lever of said plurality of levers of the control mechanism. As a variant, there is nothing to prevent the provision of a fluid guiding stator device in which only some blades are driven blades rotationally coupled with the levers of said plurality of levers. In particular, small connecting rods can thus be provided between the driven blades and the blades which are not coupled to the levers such that these latter blades are rotationally driven via said small connecting rods by the blades coupled to the levers.
In order to couple the levers - in particular the axial holding levers - of the control mechanism to the blades, provision can advantageously be made that each blade comprises a transmission shaft extending along said pivoting axis of this blade and that a ring of the stationary blade assembly, in particular the ring of the stationary blade assembly facing the control ring, comprises a plurality of bearings for receiving the transmission shafts, each transmission shaft passing through a bearing of said ring of the stationary blade assembly to an end of the transmission shaft coupled to a lever of said plurality of levers of the mechanism for controlling the angular position of the blades of the stationary blade assembly. Therefore, each blade is rotationally guided by a lever via the transmission shaft of this blade.
Furthermore, each driving lever co-operates, in rotation, with the control ring. More particularly, in some advantageous embodiments in accordance with the invention, each lever of said plurality of levers is a driving lever in contact with the control ring so as to be able to be rotationally driven by the control ring. However, there is nothing to prevent the provision of a control mechanism in which only some of the levers are driving levers in contact with the control ring to be rotationally driven by the control ring. Small connecting rods can thus be provided between the driving levers in contact with the control ring and the levers which are not in contact with the control ring such that these latter levers are rotationally driven via said small connecting rods by the driving levers.
A fluid guiding stator device in accordance with the invention is adapted to guide an incompressible fluid (liquid) or a compressible fluid (air, gas, vapours ...).
A fluid guiding stator device in accordance with the invention is adapted to be integrated into a turbomachine. In particular, in some embodiments in accordance with the invention a fluid guiding stator device in accordance with the invention can be adapted to guide a flow of fluid to a turbine of a turbomachine, the fluid guiding stator device thus being designated by the term "distributor". Furthermore, in some other embodiments in accordance with the invention a fluid guiding stator device in accordance with the invention can be adapted to guide a flow of fluid from a compressor of a turbomachine, the fluid guiding stator device thus being designated by the term "diffusor".
Therefore, the invention relates to a turbomachine comprising

a stator,
at least one wheel mounted to rotate with respect to the stator,
at least one fluid guiding stator device fixedly attached to the stator, characterised in that at least one fluid guiding stator device is a fluid guiding stator device in accordance with the invention.

More particularly, in some embodiments, one of the two rings of the stationary blade assembly is formed in the stator of the turbomachine. Nevertheless, in some other embodiments, both of the rings of the stationary blade assembly are formed in two pieces which are distinct from the stator.
Moreover, the invention also relates to a turbine distributor characterised in that it is formed by a fluid guiding stator device in accordance with the invention.
The invention likewise relates to a compressor diffusor characterised in that it is formed by a fluid guiding stator device in accordance with the invention.
The invention thus likewise relates to a turbomachine comprising a distributor in accordance with the invention. The invention likewise relates to a turbomachine comprising a diffusor in accordance with the invention. Furthermore, the invention likewise relates to a turbomachine comprising a distributor in accordance with the invention and a diffusor in accordance with the invention.
Therefore, advantageously and in accordance with the invention, since the turbomachine is a radial turbomachine comprising at least one blade assembly mobile about an axis of rotation, said guiding faces of the stationary blade assembly of the guide stator device are thus planar faces radial with respect to the axis of rotation of the turbomachine.
According to the invention, at least two levers, named radial holding levers, of said plurality of levers are arranged so as to form radial stops against the control ring.
Preferably, the control ring is radially held exclusively by said radial holding levers.
Therefore, in a guide stator device in accordance with the invention, the radial and axial holding of the control ring does not require any additional part for the guide stator device other than the levers of the mechanism for controlling the angular position of the blades of the stationary blade assembly.
Preferably, each radial holding lever is a driving lever coupled to a driven blade of the stationary blade assembly.
In accordance with the invention, some radial holding levers are also axial holding levers. Therefore, in these embodiments, at least three axial holding levers are arranged to form radial stops against the control ring such that the control ring is radially held exclusively by said at least three axial holding levers. Preferably, each radial holding lever is an axial holding lever. Advantageously, each axial holding lever is likewise a radial holding lever. In some embodiments, each lever of said plurality of levers is an axial holding lever and a radial holding lever.
As a variant, said radial holding levers can be different from the axial holding levers. The axial holding levers thus permit only axial holding of the control ring and the radial holding levers permit only radial holding of the control ring.
In some preferred embodiments, at least one axial holding lever, named internal lever, is arranged to form an axial stop against the control ring on the main axis in a first axial direction - in any rotational position of the control ring - and in that at least one axial holding lever, named external lever, is arranged to form an axial stop against the control ring on the main axis in a second axial direction opposite the first axial direction.
In particular, in some advantageous embodiments in accordance with the invention the control ring extends in a main plane, and in that each axial holding lever comprises a support portion, named axial support, the axial support of each internal lever extending from a first side with respect to said main plane and forming a first axial stop against the control ring, and the axial support of each external lever extending from a second side, opposite to said first side, with respect to said main plane and forming a second axial stop against the control ring.
Each internal lever and each external lever thus each have a single axial support.
More particularly, the axial support of each internal lever is in abutment against a surface, named first surface, of the control ring and the axial support of each external lever is in abutment against a surface of the control ring opposite to said first surface with respect to said main plane.
Preferably, a fluid guiding stator device in accordance with the invention has internal levers and external levers arranged alternately around said main axis.
This arrangement of internal levers and external levers allows the control ring to be held axially in a uniform manner.
Nevertheless, there is nothing to prevent the provision of any other arrangement of internal levers and external levers of the control mechanism.
In accordance with the invention, each lever of said plurality of levers has a proximal end rotationally coupled to a blade of said plurality of blades, and a distal end, named head. Furthermore, preferably the head of each axial holding lever forms said axial support of this lever.
Nevertheless, there is nothing to prevent the provision of an axial holding lever having said axial support in a zone of this lever between said proximal end and said distal end.
As a variant of the embodiments in which each internal lever and each external lever has a single axial support, there is nothing to prevent the provision of a control mechanism in which at least one axial holding lever is arranged to form two axial stops against the control ring on the main axis in mutually opposing directions. It is, for example, possible to provide a plurality of radial cavities in the control ring facing said main axis, said cavities being adapted to receive a distal end of the axial holding levers, the distal end forming axial stops against the cavity so as to allow the control ring to be axially held. In addition, said radial cavities and the axial holding levers are adapted to allow the axial holding levers to be rotationally driven by rotating the control ring. In some of these embodiments, radial holding can likewise be achieved by the distal end of at least three axial holding levers - in particular by the distal end of the set of levers of said plurality of levers - placed against a base of the cavity receiving this distal end.
There is likewise nothing to prevent the provision of a control mechanism in which each axial holding lever has two fingers each forming an axial stop against the control ring coming to be placed between said fingers of each axial holding lever. In particular, the control ring can have a circular, peripheral protrusion about said main axis, this protrusion being able to be arranged between said fingers of each axial holding lever.
Furthermore, in some advantageous embodiments in accordance with the invention, each radial holding lever comprises a support portion, named radial support, forming a radial stop against the control ring so as to prevent any movement of the control ring towards said main axis.
In particular, the radial support of each radial holding lever allows this lever to be rotationally guided about its axis of rotation, i.e. about the pivoting axis of the blade to which it is coupled, by the control ring so as to be able to rotationally drive the blade of the stationary blade assembly to which this lever is coupled.
In a preferred embodiment in accordance with the invention, the head of each radial holding lever is arranged to form said radial support of this lever.
Preferably, when each radial holding lever is likewise an axial holding lever, for each head of a radial holding lever, said radial support is arranged at least substantially orthogonally to said axial support of this lever.
Furthermore, advantageously and in accordance with the invention, the control ring has radial recesses, named guiding recesses, arranged about said main axis, each guiding recess being adapted to receive a head of a lever - in particular an axial holding lever - of said plurality of levers.
Each guiding recess allows the control ring to be rotationally coupled to the lever whose head is received by this guiding recess. In particular, said radial support of the head of each radial holding lever is placed in abutment against the guiding recess receiving this lever.
In some advantageous embodiments in accordance with the invention, the control ring is arranged to form stops delimiting end rotational positions of said levers.
Preferably, said stops delimiting end rotational positions of the lever are formed on sections of the control ring between said guiding recesses.
Nevertheless, as a variant or in combination, there is nothing to prevent the provision of a fluid guiding stator device in which the end rotational positions of at least one lever are defined by stops connected to a ring of the stationary blade assembly, in particular the ring facing the control ring.
Furthermore, advantageously and in accordance with the invention, said radial support of each radial holding lever and said control ring have conjugate shapes able to allow said radial support of each radial holding lever to roll, without sliding, against said control ring.
Therefore, the radial holding levers can be displaced by the control ring, reducing the stresses exerted on these levers by the control ring so as to improve the control of the angular position of the blades of the stationary blade assembly and to reduce the risk of breakdown (breaking of the levers ...).
More particularly, the head of a radial holding lever can comprise edges which can slide against the control ring during the rotation of this radial holding lever.
In particular, in some embodiments said radial support of each radial holding lever has a convex shape and each guiding recess has a surface, named drive surface, in contact with this radial support, and extending at least substantially in a plane in parallel with said main axis and with a tangent to the control ring at this guiding recess.
Therefore, said radial support of each radial holding lever is in point-wise or line-wise contact, in any angular position, with said drive surface of the guiding recess receiving this lever so as to permit slide-free rolling of the radial support of each radial holding lever against said control ring.
In particular, the drive surface of a guiding recess of the control ring defines a base of this guiding recess.
In some of these embodiments, when each radial holding lever is likewise an axial holding lever, the head of each radial holding lever has a recess between said axial support and said radial support of this lever.
This recess of this radial holding lever allows the contact surface between the axial/radial holding lever and the control ring to be reduced. Therefore, the recesses allow a reduction in the friction between the axial/radial holding levers and the control ring when the control ring is rotationally driven about said main axis.
The invention likewise relates to a fluid guiding stator device, a turbomachine, a turbine distributor and a compressor diffusor which are characterised in combination by all or some of the features mentioned above or below.
Other aims, features and advantages of the invention will become apparent upon reading the following description given by way of nonlimiting example and which makes reference to the attached figures in which:

figures 1 and 2 are perspective views of fluid guiding devices in accordance with two different embodiments in accordance with the invention,
figures 3 and 4 are two perspective views of a lever of a fluid guiding stator device in accordance with one embodiment and in accordance with the invention.

Figures 1 and 2 show fluid guiding devices 20 in accordance with two different embodiments of the invention. These devices 20 are fluid guiding devices for a radial turbomachine (not shown).
Each fluid guiding stator device 20 comprises a stationary blade assembly 21. The stationary blade assembly 21 comprises two rings 22 coaxial along an axis, named main axis 39, which are spaced apart from each other so as to form a passage, named fluid passage, which a fluid can pass through. More particularly, the fluid passage is delimited by faces, named guiding faces, facing each other, of the two coaxial rings 22 of the stationary blade assembly 21. Said guiding faces are planar and extend radially.
The stationary blade assembly 21 also comprises a plurality of blades 23 arranged about said main axis 39 and held in said fluid passage between the coaxial rings 22. Furthermore, the blades 23 of said plurality of blades 23 are arranged so as to form a plurality of channels in the fluid passage between every two blades and between the rings 22 of the stationary blade assembly 21. Each blade 23 is mounted to pivot with respect to the two rings 22 of the stationary blade assembly 21. In particular, in the illustrated embodiments, each blade 23 is mounted to pivot on a theoretical axis, named pivoting axis, in parallel with said main axis 39 and orthogonally to the two guiding faces.
Each blade 23 can thus be pivoted between two end angular positions. The angle between a longitudinal axis of a blade 23 and a diametral plane of the stationary blade assembly 21 passing through the pivoting axis of this blade 23 is the same for all the blades 23. A modification of the angular position of a blade 23 results in a modification of the geometric characteristics of each channel delimited by this blade 23, and consequently of the fluid passage.
A first end angular position of the blades 23 defines a minimum opening of the fluid passage of the stationary blade assembly 21. The minimum opening preferably allows the fluid passage of the stationary blade assembly 21 to be blocked. A second end angular position defines a maximum opening of the fluid passage of the stationary blade assembly 21.
The fluid passage of the stationary blade assembly 21 thus has a variable cross-section. The guide stator device 20 with a stationary blade assembly 21 having a variable cross-section thus allows the adjustment of a flow rate and a direction of a flow of fluid passing through said fluid passage depending upon an operating state of the turbomachine.
Each blade 23 comprises a transmission shaft 38 extending along said pivoting axis of this blade 23. A ring 22 of the stationary blade assembly 21 comprises a plurality of bearings for receiving the transmission shafts 38 of the blades 23. Each transmission shaft 38 passes through a bearing of said ring 22 of the stationary blade assembly 21.
Furthermore, each guide stator device 20 comprises a mechanism 24 for controlling the angular position of the blades 23 of the stationary blade assembly 21. The control mechanism 24 is thus able to cause the blades 23 of the stationary blade assembly 21 to pivot.
More particularly, the control mechanism 24 comprises a plurality of levers 25 arranged about the main axis 39 and a control ring 33 coaxial with respect to the rings 22 of the stationary blade assembly 21. The control ring 33 extends in a plane, named main plane, in parallel with the guiding faces of the rings 22 of the stationary blade assembly 21.
Each lever 25 is rotationally coupled with a blade 23 of the stationary blade assembly 21, each blade 23 of the stationary blade assembly 21 being rotationally coupled with a lever 25 of said plurality of levers 25. Therefore, each lever 25 allows the blade 23 to which it is coupled to be rotationally driven so as to modify its angular position.
Furthermore, each lever 25 of said plurality of levers 25 co-operates, in rotation, with said control ring 33. Therefore, the act of rotationally driving about the main axis 39 of said control ring 33 allows each lever 25 to be rotationally driven about the pivoting axis of the blade 23 to which it is connected.
Then, each lever is driven by said control ring. The control ring can be driven by an arm, named driving arm, (not shown) which can be coupled to the two rings of the blade assembly. Moreover, said driving arm is driven by a motor (not shown) for controlling the blades of the blade assembly.
As shown in figures 3 and 4, each lever 25 extends longitudinally between a proximal end 28 and a distal end, named head 29. Furthermore, as shown in figures 1 and 2, in the fluid guiding stator device 20, each lever 25 extends longitudinally orthogonally to said main axis 39.
The proximal end 28 of each lever 25 is adapted to be rotationally coupled with a blade 23 of the stationary blade assembly 21, in particular with the transmission shaft 38 of this blade 23. The proximal end 28 of each lever 25 comprises a through-orifice 37 having at least one rotationally cylindrical section extending along said pivoting axis of the blade 23 to which the lever 25 is coupled. The orifice 37 of each lever 25 is coupled to an end of a transmission shaft 38 of a blade 23, the transmission shaft 38 passing through the bearings of the ring 22 of the stationary blade assembly 21 facing the control ring 33 as far as this coupled end. Therefore, each blade 23 is rotationally guided by a lever 25 via the transmission shaft 38 of this blade 23.
In the embodiment illustrated in figure 2, the orifice 37 of each lever 25 has a plurality of ribs allowing the coupling between the transmission shaft 38 and the orifice 37 of the lever 25 to be facilitated. The coupling between the transmission shaft 38 and the orifice 37 of the lever can be done by riveting or by welding for example.
The head 29 of each lever 25 is adapted to co-operate, in rotation, with the control ring 33. In particular, the control ring 33 has a plurality of radial recesses, named guiding recesses 34, extending away from the main axis 39 and arranged about said main axis 39. The control ring 33 thus has a wavy shape. Each guiding recess 34 is adapted to receive a head 29 of the lever 25. The head 29 of each lever 25 has a support portion, named radial support 32, forming a radial stop against the guiding recess 34 receiving the head 29 of this lever 25. Therefore, the heads 29 of the levers 25 make it possible to prevent any movement of the control ring 33 towards said main axis 39. In the embodiments illustrated in figures 1 and 2, each lever is thus a radial holding lever. Furthermore, the contact between the radial supports 32 and the guiding recesses 34 of the control ring 33 allows the levers 25 to be able to be rotationally driven when the control ring 33 is rotationally driven. More particularly, each guiding recess 34 comprises a base 35 formed by a surface, named drive surface, of the recess 34 extending at least substantially in a plane in parallel with the main axis 39 and with a tangent to the control ring 33 at this guiding recess 34. Furthermore, each radial support 32 has a convex shape such that only one point of said radial support 32 is in contact with said drive surface such that each lever 25 of said plurality of levers 25 can roll, without sliding, against said control ring 33.
Therefore, the levers 25 can be displaced by the control ring 33, reducing the stresses exerted on these levers 25 by the control ring 33 so as to improve the control of the angular position of the blades 23 of the stationary blade assembly 21 and to reduce the risk of breakdown (breaking of the levers 25...).
Therefore, rotationally displacing the control ring 33 about the main axis 39 allows the set of levers 25 of the control mechanism 24 to be simultaneously rotationally driven so as to modify the angular position of the set of blades 23 of the stationary blade assembly 21.
Furthermore, the control ring 33 is arranged so as to form stops delimiting the end rotational positions of said levers 25. Said stops 36 delimiting end rotational positions of the lever 25 are formed on sections of the control ring 33 between said guiding recesses 34. In particular, the stops 36 of the control ring 33 delimiting the end rotational positions of the lever 25 are arranged at least substantially over a single theoretical circular line of diameter d1. Furthermore, the base 35 of each guiding recess 34 in the control ring 33 is arranged at least substantially over a single theoretical circular line of diameter d2 greater than d1.
Furthermore, each head 29 of the lever 25 comprises a support portion, named axial support 31, forming an axial stop along the main axis 39 against the control ring 33. Therefore, in the embodiments illustrated in figures 1 and 2 each lever is an axial holding lever. In particular, said head 29 of a lever 25 has a section protruding from said radial support 32. Said protruding section has a distal ridge forming said axial support 31.
In particular, some levers 25, named internal levers 25a, of said plurality of levers 25 are arranged in the fluid guiding stator device 20 so as to prevent any axial movement of the control ring 33 towards the stationary blade assembly 21 along the main axis 39.
Other levers 25, named external levers 25b, of said plurality of levers 25 are arranged in the fluid guiding stator device 20 so as to prevent any axial movement of the control ring 33 in a direction away from the stationary blade assembly 21 along the main axis 39.
In the illustrated embodiments, the internal levers 25a and the external levers 25b are arranged alternately about the main axis 39. This arrangement of internal levers 25a and external levers 25b allows the control ring to be held axially in a uniform manner.
More particularly, the axial support 31 of each internal lever 25a extends from a first side with respect to said main plane and forms a first axial stop against the control ring 33. The axial support 31 of each external lever 25b extends from a second side, opposite said first side, with respect to said main plane and forms a second axial stop against the control ring 33.
The levers 25 of said plurality of levers 25 by themselves make it possible to support and hold the control ring 33.
Furthermore, each lever 25 comprises an intermediate section 30 connecting said proximal end 28 of the lever 25 and said head 29 of the lever 25. This intermediate section 30 has an offset forming a difference in level between said head 29 of the lever 25 and said proximal end 28 of the lever 25. This difference in level allows the control ring 33 to be raised with respect to the stationary blade assembly 21 such that the section of the head 29 of the internal levers 25a supporting said axial support 31 can be arranged between the stationary blade assembly 21 and the control ring 33. Furthermore, the difference in level allows the head 29 of each lever 25 to be raised with respect to the proximal end 28 of each lever 25 so as to avoid the head 29 of this lever 25 being in contact with the ring 22 of the stationary blade assembly 21 facing the control ring 33. Furthermore, said intermediate portion 30 of a lever 25 is placed against a stop 36 of the control ring 33 delimiting an end rotational position when this lever 25 has reached this end rotational position.
The section of the head 29 of each lever 25 protruding from said radial support of this lever 25 comprises a recess between said radial support and said axial support so as to reduce the contact surface between the control ring 33 and the head 29 of the lever 25. The recesses of the heads 29 of the lever 25 thus allow a reduction in the friction between the levers 25 and the control ring 33 when the control ring 33 is rotationally driven about said main axis 39.
Since the control ring 33 is held axially only by the levers 25 of the control mechanism 24, it is not necessary to provide any additional part in the guide stator device 20 to perform this technical function. The axial holding arrangement allows the design and manufacturing options for the control ring 33 to be increased. Therefore, in the embodiment illustrated in figure 1, the control ring 33 is a metal ring obtained by a die-cutting process from a metal plate. As a variant, in the embodiment illustrated in figure 2, the control ring 33 is a rigid metal wire bent by plastic deformation to form a ring having said guiding recesses 34.
Furthermore, the levers 25 of the control mechanism 24 can be obtained by lost-wax moulding, injection moulding of metal powder, stamping, or aditive manufacturing or by cold-forming.
Disclosed is thus a fluid guiding stator device 20 comprising a stationary blade assembly 21 and a mechanism 24 for controlling the angular position of the blades 23 of this stationary blade assembly 21, the control mechanism 24 comprises a plurality of levers 25 rotationally coupled to the blades 23 of the stationary blade assembly 21 and a control ring 33 co-operating, in rotation, with said plurality of levers 25, the control ring 33 being axially held exclusively by at least two levers 25 of said plurality of levers 25. In particular, the control mechanism 24 of such a guide stator device 20 is simple, reliable and inexpensive.
The invention is defined by the appended claims and solely by these.
The invention can be varied in many ways with respect to the embodiments described above and illustrated in the figures. In particular, a lever 25 can be arranged to form two mutually opposing axial stops against the control ring 33 so as to prevent any axial movement of the control ring 33.
A fluid guiding stator device 20 in accordance with the invention is adapted to guide an incompressible fluid (liquid) or a compressible fluid (air, gas, vapours ...). A fluid guiding stator device 20 can be integrated into a turbomachine. A fluid guiding stator device 20 can be used as a distributor for a turbine or as a diffusor for a compressor.

Claims

Turbomachine fluid guiding stator device, comprising:
- a blade assembly (21), named stationary blade assembly (21), comprising:
∘ two rings (22) coaxial along an axis, named main axis (39),

∘ a plurality of blades (23) held between the coaxial rings (22) of the stationary blade assembly (21) and disposed around said main axis (39), each blade (23) being mounted to pivot with respect to the two rings (22) of the stationary blade assembly (21), said plurality of blades comprising at least one blade, named driven blade,

- a mechanism (24) for controlling the angular position of the blades (23) of
the stationary blade assembly (21) comprising:
∘ a plurality of levers (25) including at least one lever, named driving lever, each driving lever being rotationally coupled with a single driven blade and each driven blade being coupled with a single driving lever,

∘ a ring (33) for controlling the angular position of the blades (23) of the stationary blade assembly (21), coaxial with the two rings (22) of the stationary blade assembly (21) and being able to be rotationally driven about the main axis (39) with respect to the two rings (22) of the stationary blade assembly (21), the control ring (33) co-operating, in rotation, with each driving lever,

∘ at least two levers, named axial holding levers, of said plurality of levers (25) being arranged so as to form axial stops along said main axis (39) against the control ring (33) such that the control ring (33) is axially held along the main axis (39) exclusively by said axial holding levers,

∘ at least two levers (25), named radial holding levers, of said plurality of levers (25) are arranged so as to form radial stops against the control ring (33), some radial holding levers being also axial holding levers,
each lever of said plurality of levers having a proximal end (28) rotationally coupled to a blade (23) of said plurality of blades (23), and a distal end, named head (29), the head (29) of each radial holding lever being also axial holding lever comprising

∘ a support portion, named axial support (31), forming an axial stop along the main axis (39) against the control ring (33),

∘ a support portion, named radial support (32), forming a radial stop against the control ring (33),
wherein the control ring has radial recesses, named guiding recesses (34), arranged about said main axis, each guiding recess being adapted to receive a head of a lever of said plurality of levers, wherein each guiding recess has a surface, named drive surface, in contact with a radial support, characterised in that said head (29) of each radial holding lever being also axial holding lever has a section protruding radially from said radial support (32) that contacts a drive surface, said protruding section having a distal ridge forming said axial support (31).
Device according to claim 1, characterised in that at least one axial holding lever, named internal lever (25a), is arranged to form an axial stop against the control ring (33) on the main axis (39) in a first axial direction, and in that at least one other axial holding lever, named external lever (25b), is arranged to form an axial stop against the control ring (33) on the main axis (39) in a second axial direction opposite the first axial direction.
Device according to claim 2, characterised in that the control ring (33) extends in a main plane, and in that each axial holding lever comprises a support portion, named axial support (31), the axial support (31) of each internal lever (25a) extending from a first side with respect to said main plane and forming a first axial stop against the control ring (33), and the axial support (31) of each external lever (25b) extending from a second side, opposite to said first side, with respect to said main plane and forming a second axial stop against the control ring (33).
Device according to any one of claims 2 or 3, characterised in that it has internal levers (25a) and external levers (25b) arranged alternately around said main axis (39).
Device according to any one of claims 1 to 4, characterised in that each lever of said plurality of levers has a proximal end (28) rotationally coupled to a blade (23) of said plurality of blades (23), and a distal end, named head (29), the head (29) of each axial holding lever forming said axial support (31) of this lever.
Device according to any one of claims 1 to 5, characterised in that each radial holding lever comprises a support portion, named radial support (32), forming a radial stop against the control ring (33) so as to prevent any movement of the control ring (33) towards said main axis (39).
Device according to claim 6, characterised in that the head (29) of each radial holding lever is arranged to form said radial support (32) of this lever.
Device according to any one of claims 1 to 7, characterised in that the control ring (33) is arranged so as to form stops delimiting end rotational positions of said levers (25).
Device according to any one of claims 6 to 8, characterised in that said radial support (32) of each radial holding lever and said control ring (33) have conjugate shapes able to allow said radial support (32) of each radial holding lever to roll, without sliding, against said control ring (33).
Device according to claim 9, characterised in that said radial support (32) of each radial holding lever has a convex shape, and in that each guiding recess (34) drive surface, in contact with this radial support (32), extends at least substantially in a plane in parallel with said main axis (39) and with a tangent to the control ring (33) at this guiding recess (34).
Device according to any one of claims 6 to 10, characterised in that each radial holding lever is likewise an axial holding lever, and in that the head (29) of each radial holding lever has a recess between said axial support (31) and said radial support (32) of this lever (25).
Turbomachine, comprising
- a stator,

- at least one wheel mounted to rotate with respect to the stator,

- at least one fluid guiding device (20) fixedly attached to the stator, characterised in that at least one fluid guiding stator device is a fluid guiding stator device according to any one of claims 1 to 11.
Turbine distributor characterised in that it is formed by a fluid guiding stator device according to any one of claims 1 to 11.
Compressor diffusor characterised in that it is formed by a fluid guiding stator device according to any one of claims 1 to 11.