ARRANGEMENT FOR A TURBOMACH

Description

FIELD OF THE INVENTION

[0001] The present invention relates to an assembly for a turbomachine.

[0002] The invention relates more specifically to an assembly for a turbomachine comprising a damper. STATE OF THE ART

[0003] A turbomachine known from the state of the art comprises a casing and a fan capable of being rotated relative to the casing, around a longitudinal axis, by means of a fan shaft.

[0004] The fan comprises a disc centered on the longitudinal axis, and a plurality of blades distributed circumferentially at the external portion of the disc.

[0005] The operating range of the blower is limited. More precisely, the evolution of a blower's compression ratio as a function of an air flow rate that it sucks in when it rotates, is restricted to a predetermined range.

[0006] Beyond this area, the fan is in fact subject to aeroelastic phenomena that destabilize it. More precisely, the air circulating through the fan in operation provides energy to the blades, and the blades respond on their own modes at levels that can exceed the endurance limit of the material from which they are made. This fluid-structure coupling therefore generates vibratory instabilities that accelerate the wear of the fan, and reduce its service life.

[0007] A fan with a reduced number of blades and subject to high aerodynamic loads is very sensitive to this type of phenomenon.

[0008] This is why it is necessary to ensure a sufficient margin between the stable operating range and the instability zones, so as to protect the endurance limits of the blower.

[0009] To do this, it is known to equip the fan with dampers. Examples of dampers have been described in documents FR 2 949 142, EP 1 985 810 and FR 2 923 557, in the name of the Applicant. These dampers are all configured to be housed between the platform and the root of each blade, within the housing delimited by the respective stilts of two successive blades. Furthermore, such dampers operate during a relative movement between two platforms of successive blades, by dissipation of the vibration energy, for example by friction. Consequently, these dampers are only concerned with damping a first vibration mode of the blades which characterizes a synchronous response of the blades to aerodynamic stresses. In this first vibration mode, the inter-blade phase shift is non-zero. Other shock absorbers have been described in US 5,820,346, CN 204941612 and FR 2 923 557.US 5,820,346 discloses a retainer attached to a rotor disc with support flanges and side walls defining a channel for receiving a "chicklet" which has an upper triangular portion.

[0010] However, such dampers are completely ineffective in damping a second vibration mode in which each blade beats relative to the disc with zero inter-blade phase shift. Indeed, in this second vibration mode, there is no relative displacement between two successive blade platforms. This particular response of the blades to aerodynamic stresses, although asynchronous, still involves a non-zero moment on the fan shaft. In addition, this second vibration mode is coupled between the blades, the disc, and the fan shaft. The amplitude of this second vibration mode is all the greater as the blades are large.

[0011] There is therefore a need to overcome at least one of the drawbacks of the state of the art described above. STATEMENT OF THE INVENTION

[0012] An aim of the invention is to dampen a vibration mode of a rotor in which the phase shift between the blades of said rotor is zero.

[0013] Another object of the invention is to influence the damping of vibration modes of a rotor in which the phase shift between the blades of said rotor is non-zero.

[0014] Another aim of the invention is to propose a simple and easy-to-implement damping solution.

[0015] For this purpose, according to a first aspect of the invention, there is provided a turbomachine assembly as indicated in claim 1.

[0016] It is by damping a displacement of the first rotor relative to the second rotor, in a plane orthogonal to the longitudinal axis, that it is possible to influence the second vibration mode. In fact, unlike the first vibration mode, the second vibration mode is characterized by a zero inter-blade phase shift. Consequently, placing a damper between two successive blades of a rotor, as has already been proposed in the prior art, produces no effect on the second vibration mode. The damper of the assembly previously described has, for its part, the advantage of influencing the second vibration mode because it acts on an effect of the second vibration mode: the displacement of the first rotor relative to the second rotor, in the plane orthogonal to the longitudinal axis. By opposing this effect, the damper disrupts its cause, i.e. damps the second vibration mode.It should nevertheless be noted that the first vibration mode also contributes to the displacement of the first rotor relative to the second rotor, in the plane orthogonal to the longitudinal axis. Consequently, by opposing this effect, the damper also contributes to disturbing another cause, i.e. damping the first vibration mode. In addition, the second support part makes it possible to improve the stability of the damper.

[0017] Advantageously, but optionally, the assembly according to the invention may further comprise one of the following characteristics, taken alone or in combination with one or more of the other following characteristics: the first bearing part is fixedly mounted on the first rotor, the damper comprises a connecting part: ∘ connecting the first bearing part to the third bearing part, and ∘ being thinned relative to the first bearing part and to the third bearing part, it further comprises a sacrificial plate: ∘ fixedly mounted on the third bearing part, and ∘ bearing on the second rotor, it further comprises: ∘ a first sacrificial plate fixedly mounted on the first bearing part and having the radially external surface of the first bearing part, and ∘ a second sacrificial plate fixedly mounted on the third bearing part and having the radially external surface of the third bearing part, a slot is provided in the first bearing part, the assembly further comprising a metal insert inserted in the slot, the second sacrificial plate being fixedly mounted on the metal insert,the damper comprises: ∘ a second support part: * coming to bear on the first rotor in a second support zone, different from the first support zone, the second support zone extending over a second angular sector around the longitudinal axis, the second angular sector being smaller than the first angular sector, and * being configured to apply a third centrifugal force on the first rotor, and ∘ another second support part: * coming to bear on the first rotor in a third support zone, different from the first support zone and the second support zone, the third support zone extending over a third angular sector around the longitudinal axis, the third angular sector being smaller than the first angular sector, and * being configured to apply a fourth centrifugal force on the first rotor, each of the second support parts has a radially external surface,coming into contact with a radially internal surface of the first rotor, at least one of the second bearing parts is fixedly mounted on the first rotor, at least one of the second bearing parts comprises a portion thinned relative to the rest of said second bearing part, at least one of the second bearing parts comprises a groove configured to promote radial deformation of said second bearing part, the second bearing parts form lateral sections extending on either side, in a circumferential direction, of the first bearing part, it further comprises a weight fixedly mounted on the damper, the weight is fixedly mounted on the first bearing part, it further comprises a weight fixedly mounted on the third bearing part, it further comprises: ∘ a first weight fixedly mounted on the first bearing part, and ∘ a second weight fixedly mounted on the third bearing part,each of the blades among the plurality of blades comprises: ∘ a blade root connecting the blade to the disc, ∘ a profiled blade, ∘ a stilt connecting the blade to the blade root, and ∘ a platform connecting the blade to the stilt and extending transversely to the stilt, the first support part coming to bear on the platform of a blade among the plurality of blades, at least one of the second support zone and the third support zone extends along an entire axial length of the platform, and the second rotor comprises a shroud, the shroud comprising a circumferential extension, the third support part coming to bear on the circumferential extension.

[0018] According to a second aspect of the invention, there is provided a turbomachine comprising an assembly as previously described, and in which the first rotor is a fan, and the second rotor is a low pressure compressor. DESCRIPTION OF FIGURES

[0019] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which: There figure 1 schematically illustrates a turbomachine, The figure 2 comprises a sectional view of a part of a turbomachine, and a curve indicating a tangential displacement of different elements of this part of the turbomachine as a function of the position of said elements along a longitudinal axis of the turbomachine, The figure 3 is a sectional view of a part of an exemplary embodiment of an assembly according to the invention, The figure 4 is a perspective view of part of an exemplary embodiment of an assembly according to the invention, The Figure 5 is a perspective view of part of an exemplary embodiment of an assembly according to the invention, The figure 6is a perspective view of a shock absorber of an exemplary embodiment of an assembly according to the invention, The figure 7 is a perspective view of a shock absorber of an exemplary embodiment of an assembly according to the invention, The figure 8 is a perspective view of a shock absorber of an exemplary embodiment of an assembly according to the invention, The figure 9 is a perspective view of part of an exemplary embodiment of an assembly according to the invention, The figure 10 is a perspective view of part of an exemplary embodiment of an assembly according to the invention, The figure 11 is a perspective view of a shock absorber of an exemplary embodiment of an assembly according to the invention, The figure 12 is a perspective view of part of an exemplary embodiment of an assembly according to the invention, The figure 13 is a perspective view of part of an exemplary embodiment of an assembly according to the invention, The figure 14is a perspective view of part of an exemplary embodiment of an assembly according to the invention, The figure 15 is a perspective view of a section of a part of an exemplary embodiment of an assembly according to the invention, The figure 16 is a perspective view of part of an exemplary embodiment of an assembly according to the invention, and The figure 17 is a perspective view of a part of an exemplary embodiment of an assembly according to the invention.

[0020] Throughout the figures, similar elements have identical references. DETAILED DESCRIPTION OF THE INVENTION Turbomachine 1

[0021] In reference to the figure 1 , a turbomachine 1 comprises a casing 10, a fan 12, a low pressure compressor 140, a high pressure compressor 142, a combustion chamber 16, a high pressure turbine 180 and a low pressure turbine 182.

[0022] Each of the blower 12, the low pressure compressor 140, the high pressure compressor 142, the high pressure turbine 180, and the low pressure turbine 182, is rotatable relative to the casing 10 around a longitudinal axis XX.

[0023] In the embodiment illustrated in figure 1 , and as also visible on the figures 2 And 3 , the blower 12 and the low pressure compressor 140 are integral in rotation, and are capable of being set in rotation by a low pressure shaft 13 which is itself capable of being set in rotation by the low pressure turbine 182. The high pressure compressor 142 is, for its part, capable of being set in rotation by a high pressure shaft 15, which is itself capable of being set in rotation by the high pressure turbine 180.

[0024] In operation, the blower 12 sucks in an air flow 110 which separates into a secondary flow 112, circulating around the casing 10, and a primary flow 111, successively compressed within the low pressure compressor 140 and the high pressure compressor 142, ignited within the combustion chamber 16, then successively expanded within the high pressure turbine 180 and the low pressure turbine 182.

[0025] Upstream and downstream are here defined with respect to the normal flow direction of air 110, 111, 112 through the turbomachine 1. Similarly, an axial direction corresponds to the direction of the longitudinal axis XX, a radial direction is a direction which is perpendicular to this longitudinal axis XX and which passes through said longitudinal axis XX, and a circumferential, or tangential, direction corresponds to the direction of a flat and closed curved line, all of whose points are at an equal distance from the longitudinal axis XX. Finally, and unless otherwise specified, the terms "internal (or interior)" and "external (or exterior)", respectively, are used with reference to a radial direction so that the internal (i.e. radially internal) part or face of an element is closer to the longitudinal axis XX than the external (i.e. radially external) part or face of the same element. 12 blower and 140 low pressure compressor

[0026] In reference to the figures 1 to 3, the fan 12 comprises a disc 120 and a plurality of blades 122 distributed circumferentially at an external portion of the disc 120. With reference to the figures 2 And 3 , each of the blades 122 of the plurality of blades 122 comprises: a blade root 1220 connecting the blade 122 to the disc 120, a profiled blade 1222, a stilt 1224 connecting the blade 1222 to the blade root 1220, and a platform 1226 connecting the blade 1222 to the stilt 1224, and extending transversely to the stilt 1224.

[0027] The blade root 1220 may be integral with the disc 120 when the fan 12 is a single-piece bladed disc. Alternatively, as seen in the figure 3 , the blade root 1220 can be configured to be housed in a cell 1200 of the disc 120 provided for this purpose.

[0028] As visible on the figures 2 , 3 And 13, the low-pressure compressor 140 also comprises a plurality of blades 1400 fixedly mounted at an external portion of a shell 1402, said shell 1402 comprising a circumferential extension 1404 at the external end of which radial sealing lips 1406 extend. The radial sealing lips 1406 come opposite the platforms 1226 of the blades 122 of the fan 12, so as to guarantee the internal sealing of the flow vein within which the primary flow 111 circulates. As more precisely visible on the figure 3 , the shell 1402 of the low pressure compressor 140 is fixed to the disc 120 of the blower 12, for example by bolting.

[0029] Each of the blades 122 of the plurality of blades 122 of the fan 12 is capable of beating, by vibrating relative to the disc 120 during a rotation of the fan 12 relative to the casing 10. More precisely, during the coupling between the air 110 circulating within the fan 12 and the profiled blades 1222, the blades 122 are the seat of aeroelastic flutter phenomena on different vibration modes, and the amplitude of which can be such that it exceeds the endurance limits of the materials constituting the fan 12. These vibration modes are further coupled to the opposing forces of compression upstream of the turbomachine 1, and of expansion downstream thereof.

[0030] A first vibrational mode characterizes a synchronous response of the blades 122 to aerodynamic stresses, in which the inter-blade phase shift is non-zero.

[0031] A second vibration mode characterizes an asynchronous response of the blades 122 to aerodynamic stresses, in which the inter-blade phase shift is zero. The amplitude of the beats of the second vibration mode is also greater the larger the blades 122 of the fan 12. Furthermore, this second vibration mode is coupled between the blades 122, the disc 120, and the fan shaft 13. The frequency of the second vibration mode is, moreover, one and a half times greater than that of the first vibration mode. Finally, the second vibration mode has a nodal deformation at mid-height of the blades 122 of the fan 12.

[0032] In vibration modes, including the second vibration mode, the flapping of the blades 122 involves a non-zero moment on the low-pressure shaft 13. In particular, these vibration modes cause intense torsional forces within the low-pressure shaft 13. The vibrations induced by the flapping of the blades 122 of the fan 12, but also by the flapping of the blades 1400 of the low-pressure compressor 140, lead to significant relative tangential displacements between the fan 12 and the low-pressure compressor 140. Indeed, the length of the blades 122 of the fan 12 is greater than the length of the blades 1400 of the low-pressure compressor 140. Consequently, the tangential bending moment caused by the flapping of a blade 122 of the fan 12 is greater than the tangential bending moment caused by flapping of a blade 1400 of the low pressure compressor 140.The blades of the blades 122 of the fan 12 and of the blades 1400 of the low-pressure compressor 140 then have very different behaviors. Furthermore, the mounting stiffness within the fan 12 is different from the mounting stiffness within the low-pressure compressor 140.

[0033] As seen more precisely on the figure 2, this results in particular in a large amplitude displacement of the fan 12 relative to the low pressure compressor 140, in a plane orthogonal to the longitudinal axis XX, at the interface between the platforms 1226 of the blades 122 of the fan 12 and the radial sealing lips 1406 of the circumferential extension 1404 of the shell 1402 of the low pressure compressor 140. The amplitude of this displacement for the second vibratory mode is for example between 0.01 and 0.09 millimeters, typically of the order of 0.06 millimeters, or, in another example, is of the order of a few tenths of a millimeter, for example 0.1 or 0.2 or 0.3 millimeters. Shock absorber 2

[0034] A damper 2 is used to dampen these vibrations of the blower 12 and / or the low pressure compressor 140.

[0035] The damper 2 is notably configured to dampen a displacement of the fan 12 relative to the low-pressure compressor 140, in a plane orthogonal to the longitudinal axis XX, the displacement being caused by a flapping of at least one blade 122 among the plurality of blades 122 of the fan 12.

[0036] In reference to the figures 3 to 17 , shock absorber 2 includes: a first support part 21: ∘ coming to bear on the fan 12 in a first support zone extending over a first angular sector A1 around the longitudinal axis XX, and ∘ being configured to apply a first centrifugal force C1 on the fan, and a second support part 22, 24 also coming to bear on the fan 12, but in a second support zone, different from the first support zone.

[0037] To apply the first centrifugal force C1, the first support part 21 has a radially external surface, corresponding to the first support zone, coming into contact with a radially internal surface of the fan 12, typically a radially internal surface of the platform 1226.

[0038] As visible in particular on the figures 5 And 12 , the second support zone extends over a second angular sector A2, A4 around the longitudinal axis XX, the second angular sector A2, A4 being less than the first angular sector A1.

[0039] All or part of the blades 122 of the fan 12 can also be equipped with such a damper 2, depending on the desired damping, but also the mounting and / or maintenance characteristics.

[0040] In one embodiment, the first support part 21 is fixedly mounted on the fan 12, for example by gluing. This facilitates the integration of the damper 2 within the turbomachine 1, and guarantees the support of the first support part 21 on the fan 12. Advantageously, with reference to figures 4 , 5 , 12 , 14 , 16 And 17 , the first angular sector A1 corresponds to the angular sector occupied by the platform 1226 of a blade 122 of the fan 12. In other words, the first support part 21 extends over the entire circumferential dimension of the platform 1226 of the blade 122, at the level of an internal surface of said platform 1226. The support of the damper 2 on the fan 12 is thus improved.

[0041] In one embodiment, the shock absorber 2 comprises a material from the range having the commercial name “SMACTANE ®< ST” and / or “SMACTANEO SP”, for example a material of the type “SMACTANE ®< ST 70” and / or “SMACTANE ®< SP 50”. It has in fact been observed that such materials have suitable damping properties.

[0042] In reference to the figures 3 to 17 , in one embodiment, the shock absorber 2 comprises a third support part 23: bearing on the low pressure compressor 140, and being configured to apply a second centrifugal force C2 on the low pressure compressor 140.

[0043] To apply the second centrifugal force C2, the third support part 23 has a radially external surface, coming into contact with a radially internal surface of the low pressure compressor 140, typically a radially internal surface of the circumferential extension 1404, for example a radially internal surface of the sealing lips 1406.

[0044] As visible on the figure 4 , the third support part 23 comes to bear on the low pressure compressor 140 in a third support zone extending over a third angular sector A3 around the longitudinal axis XX.

[0045] Alternatively, as for example illustrated in the figure 10 , the third support part 23 is fixedly mounted on the low pressure compressor 140, for example by gluing. The first support part 21 can then be mounted freely to rub on the blower 12.

[0046] In an advantageous variant of this embodiment, for example illustrated in the figures 4 , 6 , 7 , And 9 has 16 , the shock absorber 2 further comprises a connecting part 20: connecting the first support portion 21 to the third support portion 23, and being thinned relative to the first support portion 21 and the third support portion 23. More specifically, as illustrated in the figures 4 , 6 , 7 , And 9 has 11 the first support part 21 has a first radial thickness E1 in a section plane which comprises the longitudinal axis XX, the third support part 23 has a third radial thickness E3 in the section plane, and the connecting part 20 has a connecting radial thickness E0 in the section plane. figure 3 provides an example of a view in such a section plane. As seen in the figures 4 , 6 , 7 , And9 has 11 , the radial connection thickness E0 is smaller than the first radial thickness E1 and the third radial thickness E3. The connection part 20 is therefore thinned relative to the first support part 21 and the third support part 23.

[0047] Thus, the first support portion 21 and the third support portion 23 are massive. Consequently, in operation, each of the first support portion 21 and the third support portion 23 exerts a respective centrifugal force C1, C2 on the fan 12 and the low-pressure compressor 140, on which said support portions 21, 23 come to bear. In this way, the support portions 21, 23 are each dynamically coupled respectively to the fan 12 and to the low-pressure compressor 140 on which each comes to bear, so as to undergo the same vibrations as each of the fan 12 and the low-pressure compressor 140. In addition, the support portions 21, 23 are stiffer than the connecting portion 20, in particular in a tangential direction. Advantageously, as for example visible on the figure 4 , the third radial thickness E3 is greater than the first radial thickness E1, so as to better guarantee the support of the third support part 23.

[0048] The thinner connecting portion 20 is more flexible, particularly in a tangential direction. It therefore allows the blower 12 to transmit the vibrations to which it is subject to the low-pressure compressor 140 and, conversely, it allows the low-pressure compressor 140 to transmit the vibrations to which it is subject to the blower 12. Indeed, for high vibration frequencies, damping is provided in particular by the shear work of the connecting portion 20, i.e. by viscoelastic dissipation. For low vibration frequencies, damping is provided in particular by friction of one or the other of the first support portion 21 or third support portion 23 respectively against the blower 12 or against the low-pressure compressor 140.

[0049] Furthermore, the third bearing portion 23 bears on the circumferential extension 1404 of the shell 1402 of the low-pressure compressor 140, at an internal surface of the radial sealing lips 1406. Indeed, it is at this position that the displacement of the blower 12 relative to the low-pressure compressor 140, in the plane orthogonal to the longitudinal axis XX, is of greater amplitude, typically a few millimeters. Consequently, the damper 2 is particularly effective there. Furthermore, the thinning of the connecting portion 20 ensures a clearance which allows the damper 2 to avoid rubbing on a corner of the radial sealing lips 1406.

[0050] In one embodiment, for example illustrated in the figures 12 , 13 , 15 And 17, the second support part 22, 24 is configured to apply a third centrifugal force C3, C4 on the fan 12. To do this, the second support part 22, 24 has a radially external surface coming into contact with a radially internal surface of the fan 12. In an advantageous variant, the second support part 22 also comes into contact with a downstream surface of the stilt 1224 of the blade 122, as visible in the figures 4 And 5 . In another variation, illustrated on the figures 12 to 17 , the second support part 22, 24 comes to bear under the platform 1226 of a blade 122 of the fan 12, at the level of an internal surface of the platform 1226.

[0051] In reference to the figure 6, in one embodiment, a sacrificial plate 230 rests on the low pressure compressor 140. The sacrificial plate 230 is fixedly mounted on the third support part 23, for example by gluing, and / or by being housed within a groove 2300 of the third support part 23 provided for this purpose, as visible in the figure 6. The sacrificial plate 230 is configured to ensure the support of the third support part 23 on the low pressure compressor 140. Indeed, the mechanical stresses during operation are such that slight tangential, axial and radial movements of the damper 2 are to be expected. These movements are notably due to the vibrations to be damped, but also to the centrifugal loading of the damper 2. It is necessary that these movements do not wear out the low pressure compressor 140. In this regard, the sacrificial plate 230 comprises an anti-wear material, for example of the Teflon type and / or any type of composite material. In an advantageous configuration, the sacrificial plate 230 is further treated by dry lubrication, in order to perpetuate the value of the coefficient of friction between the damper 2 and the low pressure compressor 140. This material with lubricating properties is for example of the MoS2 type.Advantageously, the sacrificial plate 230 may also comprise an additional coating, configured to reduce the friction and / or wear of the low-pressure compressor 140. This additional coating is fixedly mounted on the sacrificial plate 230, for example by gluing. The additional coating is of the dissipative and / or viscoelastic and / or damping type. It may in fact comprise a material from the range having the commercial name “SMACTANE ®< ST” and / or “SMACTANEO SP”, for example a material of the type “SMACTANE ®< ST 70” and / or “SMACTANE ®< SP 50”. It may also comprise a material chosen from those having mechanical properties similar to those of Vespel, Teflon or any other material with lubricating properties. More generally, the additional coating material advantageously has a coefficient of friction of between 0.3 and 0.07.The sacrificial plate 230 is possibly combined by juxtaposition with its additional coating. Indeed, it makes it possible to increase the friction, in particular tangential, of the damper 2 when, in operation, the sacrificial plate 230 is sufficiently constrained by the second centrifugal force C2 so that the displacement of the fan 12 relative to the low-pressure compressor 140, in the plane orthogonal to the longitudinal axis XX, is damped by energy dissipation by means of a viscoelastic shear of the sacrificial plate 230.

[0052] In reference to the figures 7 And 16 , in one embodiment: the first bearing portion 21 has a first bearing surface 2100 arranged to apply a first force F1 to the low-pressure compressor 140, the first force F1 having a first longitudinal component F1L in a first direction parallel to the longitudinal axis XX, and a first radial component F1R in a second direction orthogonal to the longitudinal axis XX, the first longitudinal component F1L being greater than the first radial component F1R, the third bearing portion 23 has a second bearing surface 2320 arranged to apply a second force F2 to the low-pressure compressor 140, the second force F2 having a second longitudinal component F2L in the first direction, and a second radial component F2R in the second direction, the second radial component F2R being greater than the second longitudinal component F2L.

[0053] In other words, the first bearing surface 2100 provides axially positioned support for the damper 2 since it is a downstream axial surface of the damper 2 coming into contact with an upstream axial surface of the low-pressure compressor 140. Furthermore, the second bearing surface 2320 provides radially positioned support for the damper 2 since it is a radially external surface of the damper 2 coming into contact with a radially internal surface of the low-pressure compressor 140. Furthermore, in operation, the second bearing surface 2320 participates in the application of the second centrifugal force C2 on the low-pressure compressor 140.

[0054] In reference to the figure 8 , in an advantageous variant of the embodiment illustrated in figures 7 And 16 : a first sacrificial plate 210 is fixedly mounted on the first support part 21, for example by gluing, and has the first support surface 2100, and a second sacrificial plate 232 is fixedly mounted on the third support part 23, for example by gluing, and has the second support surface 2320.

[0055] The first sacrificial wafer 210 and the second sacrificial wafer 232 advantageously have the same characteristics as those described with reference to the sacrificial wafer 230 of the embodiment illustrated in figure 6 , with the same benefits for damping a displacement of the blower 12 relative to the low pressure compressor 140, in the plane orthogonal to the longitudinal axis XX.

[0056] Still referring to the figure 8, also advantageously, a slot 213 is provided in the first support part 21, a metal insert 233 being inserted into the slot 213, the second sacrificial plate 232 being fixedly mounted on the metal insert 233, for example by gluing. The metal insert 233 makes it possible to stiffen the shock absorber 2. In addition, the metal insert 233 facilitates the deformation of the first sacrificial plate 210 and the second sacrificial plate 232.

[0057] In reference to the figures 9 to 11, in one embodiment, a weight 3 is fixedly mounted on the damper 2, for example by gluing. The weight 3 makes it possible to adjust the centrifugal forces C1, C2, C3, C4 exerted by the damper 2 on the fan 12 and on the low-pressure compressor 140, so as to improve the dynamic coupling between the first support part 21 and the fan 12, and between the third support part 23 and the low-pressure compressor 140. Advantageously, the weight 3 comprises an elastomeric material. With reference to the figure 9 , the weight 3 can then be fixedly mounted both on the first support part 21 and on the third support part 23, for example by gluing.

[0058] In reference to the figure 10 , in an advantageous variant, the weight 3 is fixedly mounted on the first support part 21, for example by gluing, preferably only on the first support part 21. Advantageously, as visible on the figure 10, the weight is offset upstream of the first support part 21, so as to leave the connecting part 20 free so that, in operation, it can effectively work in shear to dampen a movement of the fan 12 relative to the low-pressure compressor 140, in a plane orthogonal to the longitudinal axis XX. Alternatively, the weight 3 is fixedly mounted on the third support part 23, for example by gluing, preferably only on the third support part 23. Advantageously, and for the same reasons as those mentioned with reference to the first support part 21, the weight 3 is offset downstream of the third support part 23. Preferably, the weight 3 is fixedly mounted only on the first support part 21 if the third support part 23 is fixedly mounted on the low-pressure compressor 140.

[0059] In another advantageous variant, with reference to the figure 11 : a first weight 31 is fixedly mounted on the first support part 21, and a second weight 32 is fixedly mounted on the third support part 23.

[0060] In this way, it is possible to independently adjust the first centrifugal force C1 and the second centrifugal force C2. This makes it possible to improve vibration damping by targeting the vibration modes specific to the blower 12 and specific to the low-pressure compressor 140.

[0061] In reference to the figures 12 to 17 , in one embodiment, the shock absorber 2 comprises: a second support portion 22: ∘ coming to bear on the fan 12 in a second support zone, different from the first support zone, the second support zone extending over a second angular sector A2 around the longitudinal axis XX, the second angular sector A2 being smaller than the first angular sector A1, and ∘ being configured to apply a third centrifugal force C3 on the fan 12, and another second support portion 24: ∘ coming to bear on the fan 12 in a third support zone, different from the first support zone and the second support zone, the third support zone extending over a third angular sector A4 around the longitudinal axis XX, the third angular sector A4 being smaller than the first angular sector A1, and ∘ being configured to apply a fourth centrifugal force C4 on the fan 12.

[0062] To apply the third centrifugal force C3, and the fourth centrifugal force C4, each of the second support parts 22, 24 has a radially external surface, coming into contact with a radially internal surface of the fan 12, typically a radially internal surface of the platform 1226.

[0063] As visible on the figures 12 to 17, the two second support portions 22, 24 form lateral sections extending on either side, in a circumferential direction, of the first support portion 21. Thus, the two second support portions 22, 24 promote coupling with the fan 12, and damping of a movement of the fan 12 relative to the low-pressure compressor 140, by increasing the overall stiffness of the first support portion 21. Furthermore, the stiffness of the first support portion 21 is increased at its circumferential ends. The damping of the damper 2, in particular in a tangential direction, is then generally improved.

[0064] In an advantageous variant of this embodiment, at least one of the first support part 21 and the two second support parts 22, 24 is fixedly mounted on the fan 12, for example by gluing. This facilitates the integration of the damper 2 within the turbomachine 1, and guarantees the support of said support parts 21, 22, 24 on the fan 12. In an equally advantageous variant, as seen in the figures 12 , 13 , 14 , 16 And 17 , each of the first support part 21, and of the two second support parts 22, 24 comes to bear on the blade platform 122 of the fan 12, at the level of an internal surface of the platform 1226.

[0065] In reference to the figures 14 And 17, in a variant of this embodiment, at least one of the two second support zones 22, 24 extends along an entire axial length of the platform 1226. In other words, at least one of the two second parts 22, 24 extends along the entire length of the platform 1226. Advantageously, as also visible in the figures 14 And 17, at least one of the two second support portions 22, 24 is flush with an edge of the platform 1226. In other words, a radial surface of the platform 1226 at a circumferential end of said platform 1226 is extended by a radial surface of the second support portion 22, 24 at a circumferential end of said second support portion 22, 24 which corresponds to the circumferential end of the platform 1226. In this way, the second support portions 22, 24 of dampers 2 circumferentially adjacent within the fan 12 come to bear against each other. This contributes to the frictional damping of the vibrations of the blower 12. In addition, these supports of the second support parts 22, 24 of dampers 2 circumferentially adjacent to each other improve the sealing of the air flow vein 110. In an advantageous variant, for example illustrated in figure 17, only one of the second support parts 22, 24 extends along the entire length of the platform 1226, flush with an edge of the platform 1226, while the other of the second support parts 22, 24 extends only along a portion of the platform 1226. Thus, only the axially longest second support part 22, 24 participates in sealing while the other participates rather in damping.

[0066] In reference to the figure 15 , in another variant of this embodiment, at least one of the second support parts 22, 24 comprises a portion thinned relative to the rest of said second support part 22, 24. More precisely, as visible on the figure 15, a first circumferential thickness e1 of the second support portion 22, 24 is different from a second circumferential thickness e2 of the second support portion 22, 24, said second circumferential thickness e2 being taken at a radial position different from a radial position of the first circumferential thickness e1. Advantageously, as visible on the figure 15, at least one of the second support portions 22, 24 is thicker at an internal surface of the platform 1226 than at a distance from the internal surface of the platform 1226. This makes it possible to stiffen said second support portion 22, 24 in order to promote the application of the corresponding centrifugal force C3, C4 on the fan 12. In addition, the presence of the first circumferential thickness e1 facilitates the holding, for example by gluing, of the second support portion 22, 24 on the internal surface of the platform 1226. Finally, the presence of the second circumferential thickness e2 improves the sealing between the circumferentially adjacent second support portions 22, 24.

[0067] Still referring to the figure 15 , but as also visible on the figures 14 And 16, in an advantageous variant of this embodiment, at least one of the second support parts 22, 24 comprises a groove 241. The groove 241 is configured to promote radial deformation of said second support part 22, 24 during the application of the corresponding centrifugal force C3, C4. This notably promotes sealing between the platforms 1226 of the successive blades 122 of the fan 12. In this embodiment, it can also be seen that the support parts 21, 22, 23, 24 are solid. Consequently, in operation, each of said support parts 21, 22, 23, 24 exerts a respective centrifugal force C1, C2, C3, C4 on the blower 12 and the low pressure compressor 140, on which said support parts 21, 22, 23, 24 come to bear.In this way, the support parts 21, 22, 23, 24 are each dynamically coupled respectively to the blower 12 and to the low pressure compressor 140 on which each comes to bear, so as to undergo the same vibrations as each of the blower 12 and the low pressure compressor 140. Furthermore, in the variant of this embodiment where the damper 2 comprises a connecting part 20, the support parts 21, 22, 23, 24 are stiffer than the connecting part 20, in particular in a tangential direction.

[0068] In all that has been described previously, the damper 2 is configured to dampen a displacement of the fan 12 relative to the low pressure compressor 140, in the plane orthogonal to the longitudinal axis XX.

[0069] This is not, however, limiting, since the damper 2 is also configured to dampen a displacement of any first rotor 12 relative to any second rotor 140, in a plane orthogonal to the longitudinal axis XX, as long as the first rotor 12 is rotatable relative to the casing 10 around the longitudinal axis XX and comprises a disk 120 as well as a plurality of blades 122 capable of beating while vibrating relative to the disk 120 during a rotation of the first rotor 12 relative to the casing 10, and that the second rotor 140 is also rotatable relative to the casing 10 around the longitudinal axis XX.

[0070] Thus, the first rotor 12 may be a first stage of the high-pressure compressor 142 or low-pressure compressor 140, and the second rotor 140 may be a second stage of said compressor 140, 142, successive to the first stage of compressor 140, 142, upstream or downstream of the latter. Alternatively, the first rotor 12 may be a first stage of a high-pressure turbine 180 or low-pressure turbine 182, and the second rotor 140 may be a second stage of said turbine 180, 182, successive to the first stage of turbine 180, 182, upstream or downstream of the latter.

[0071] In any case, the damper 2 has a small footprint. Consequently, it can easily be integrated into existing turbomachines.

[0072] Furthermore, by being configured to exert centrifugal forces C1, C2, C3, C4 on the first rotor 12 and, optionally, on the second rotor 140, the damper 2 ensures significant tangential stiffness between the first rotor 12 and the second rotor 140. It thus differs from an overly flexible damper which would only deform during a displacement of the first rotor 12 relative to the second rotor 140, in the plane orthogonal to the longitudinal axis XX. On the contrary, the damper 2 dissipates such a displacement: either by friction and / or oscillations between a state where the damper 2 is stuck on the rotors 12, 140 and a state where the damper 2 slides on the rotors 12, 140, which makes it possible to dampen in particular the low frequencies, or by viscoelastic shear within the damper 2, which makes it possible to dampen in particular the high frequencies.

[0073] However, the damper 2 remains sufficiently flexible to maximize the contact surfaces between said damper 2 and the rotors 12, 140 on which it rests. To do this, the damper 2 has a tangential rigidity greater than an axial rigidity and a radial rigidity.

[0074] The contact forces between the damper 2 and the rotors 12, 140 may in particular be adjusted by means of weights 3 and / or sacrificial plates 230, 210, 232 and / or additional coatings on said sacrificial plates 230, 210, 232. At low frequencies, it is indeed necessary to ensure that the centrifugal forces C1, C2, C3, C4 exerted by the damper 2 on the rotors 12, 140 are not too great, in order to guarantee that the damper 2 can oscillate between a stuck state and a sliding state on the rotors 12, 140, and thus dampen by friction. At high frequencies, on the other hand, it is necessary to ensure that the centrifugal forces C1, C2, C3, C4 exerted by the damper 2 on the rotors 12, 140 are sufficiently large so that the prestressing of the damper 2 on the rotors 12, 140 is sufficient, in order to guarantee that the damper 2 can be the seat of viscoelastic shear.

[0075] The wear of the rotors 12, 140 is limited in particular by treating the surfaces of the damper 2 bearing on the rotors 12, 140, for example to provide them with a coating with a low coefficient of friction.

Claims

1. Turbomachine assembly (1) comprising : - a housing (10), - a first rotor (12) o rotatable relative to the housing (10) about a longitudinal axis (X-X), and o including : * a disc (120), and * a plurality of blades (122) capable of beating relative to the disc (120) during a rotation of the first rotor (12) relative to the housing (10), - a second rotor (140) rotatable relative to the housing (10) about the longitudinal axis (X-X), and - a damper (2) configured to damp a displacement of the first rotor (12) relative to the second rotor (140), in a plane orthogonal to the longitudinal axis (X-X), the displacement being caused by a beat of at least one blade (122) of the plurality of blades (122), the damper (2) comprising : o a first support part (21): * bearing on the first rotor (12) in a first bearing zone extending over a first angular sector (A1) around the longitudinal axis (X-X), * being configured to apply a first centrifugal force (C1) to the first rotor (12), and * having a radially outer surface in contact with a radially inner surface of the first rotor (12), o a second support part (22, 24) : * bearing on the first rotor (12) in a second bearing zone, different from the first bearing zone, the second bearing zone extending over a second angular sector (A2, A4) around the longitudinal axis (X-X), the second angular sector (A2, A4) being smaller than the first angular sector (A1), * being configured to apply a third centrifugal force (C3, C4) to the first rotor (12), and * having a radially outer surface in contact with a radially inner surface of the first rotor (12), and o a third support part (23): * bearing on the second rotor (140), * being configured to apply a second centrifugal force (C2) to the second rotor (140), and * having a radially outer surface in contact with a radially inner surface of the second rotor (140).

2. Assembly according to claim 1, in which the first support part (21) is fixedly mounted on the first rotor (12).

3. Assembly according to claim 1, in which the damper (2) comprises a connecting part (20): - connecting the first support part (21) to the third support part (23), and - being thinner than the first support part (21) and the third support part (23).

4. Assembly according to one of claims 1 to 3, the assembly further comprising a sacrificial plate (230): - fixed to the third support part (23), and - bearing on the second rotor (140).

5. Assembly according to one of claims 1 to 4, the assembly further comprising: - a first sacrificial plate (210) fixedly mounted on the first bearing part (21) and presenting the radially outer surface of the first bearing part (21), and - a second sacrificial plate (232) fixedly mounted on the third bearing part (23) and presenting the radially outer surface of the third bearing part (23).

6. Assembly according to claim 5, in which a slot (213) is provided in the first bearing portion (21), the assembly further comprising a metal insert (233) inserted in the slot (213), the second sacrificial plate (232) being fixedly mounted on the metal insert (233).

7. Assembly according to one of claims 1 to 6, in which the damper (2) comprises - a second support part (22) o bearing on the first rotor (12) in a second bearing zone, different from the first bearing zone, the second bearing zone extending over a second angular sector (A2) about the longitudinal axis (X-X), the second angular sector (A2) being smaller than the first angular sector (A1), and o being configured to apply a third centrifugal force (C2) to the first rotor (12), and - another second support part (24) o bearing on the first rotor (12) in a third bearing zone, different from the first bearing zone and the second bearing zone, the third bearing zone extending from the first bearing zone to the second bearing zone over a third angular sector (A4) about the longitudinal axis (X-X), the third angular sector (A4) being smaller than the first angular sector (A1), and o being configured to apply a fourth centrifugal force (C4) to the first rotor (12).

8. Assembly according to claim 7, in which each of the second support parts (22, 24) has a radially outer surface, contacting a radially inner surface of the first rotor (12).

9. Assembly according to one of claims 7 and 8, in which at least one of the second bearing parts (22, 24) is fixedly mounted on the first rotor (12).

10. Assembly according to one of claims 7 to 9, in which at least one of the second bearing parts (22, 24) comprises a thinned portion relative to the remainder of said second bearing part (22, 24).

11. Assembly according to one of claims 7 to 10, wherein at least one of the second bearing portions (22, 24) comprises a groove (241) configured to promote radial deformation of said second bearing portion (22, 24).

12. Assembly according to one of claims 7 to 11, in which the second parts bearing parts (22, 24) form lateral sections extending on either side of the first bearing part (21) in a circumferential direction.

13. Assembly according to one of claims 1 to 12, the assembly further comprising a flyweight (3) fixedly mounted on the damper (2).

14. Assembly according to claim 13, in which the flyweight (3) is fixedly mounted on the first support part (21).

15. Assembly according to one of claims 1 to 14, the assembly further comprising a masselotte (3) fixed to the third support part (23).

16. Assembly according to one of claims 1 to 12, the assembly further comprising: - a first flyweight (31) fixedly mounted on the first support part (21), and - a second flyweight (32) fixed to the third support part (23).

17. An assembly according to any one of claims 1 to 16, wherein each of the plurality of blades (122) comprises: - a blade foot (1220) connecting the blade (122) to the disc (120), - a profiled blade (1222), - a stilt (1224) connecting the blade (1222) to the blade foot (1220), and - a platform (1226) connecting the blade (1222) to the stilt (1224) and extending transversely to the stilt (1224), the first bearing portion (21) bearing on the platform (1226) of one blade (122) of the plurality of blades (122).

18. Assembly according to claim 17, in combination with one of claims 7 to 16, in which at least one of the second support zone and the third support zone extends along an entire axial length of the platform (1226).

19. Assembly according to one of claims 1 to 18, in which the second rotor (140) comprises a ferrule (1402), the ferrule (1402) comprising a circumferential extension (1404), the third support part (23) bearing on the circumferential extension (1404).

20. Turbomachine (1) comprising an assembly according to one of claims 1 to 19, and in which the first rotor (12) is a fan and the second rotor (140) is a low-pressure compressor.