ASSEMBLY INCLUDING A BALANCING DEVICE FOR A ROTARY PART

Abstract

A first aspect of the invention relates to an assembly (2) comprising a rotating part (10) having a wall (12) and an orifice (14) passing through the wall (12). The assembly (2) further comprises at least one balancing device (200) having a screw (210) having a head (212) and a shaft (214) received in the orifice, at least one centering washer (230) held between the head of the screw and the wall of the rotating part, and a nut (220) cooperating with the shaft of the screw. The washer (230) of the assembly (2) comprises a first portion (234) with an external diameter D1, a second portion (236) with an external diameter D2 greater than D1, and a cylindrical receiving recess (240) arranged in the second portion. Figure to be published with the abbreviation: Figure 3

Description

Title of the invention: ASSEMBLY COMPRISING A BALANCING DEVICE FOR A ROTARY PART TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates more particularly to the field of turbomachinery and especially to the balancing of a rotating part of a turbomachine.

[0002] The present invention relates more particularly to an assembly comprising a rotating part and a device for balancing a rotating part. The invention also relates to a balancing method. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Conventionally, balancing a rotating part of a turbomachine allows the mass of the rotating part to be centered and thus limits any vibration phenomena during the operation of the turbomachine. Balancing compensates for defects in the rotating part or for instrumentation problems and is generally carried out on a test bench.

[0004] There are devices for balancing a rotating part in the form of additional parts forming a balancing mass that can be adjusted by adding or removing additional parts.

[0005] Figure 1 illustrates an assembly 2 comprising a rotating part 10 and at least one balancing device 200 according to an example of the prior art. The rotating part 10 with axis of rotation X0 comprises a wall 12 and an orifice 14 passing through the wall 12.

[0006] The balancing device 200 comprises: - a screw 210 comprising a head 212 and a shaft 214, - at least one centering washer 231 for axis XI, and - a 220 nut. In the assembled position of the balancing device 200 on the rotating part 10 of assembly 2: - the screw 210, the centering washer 231 and the nut 220 are axially aligned along axis XI, - the centering washer 231 is held between the head 212 of the screw 210 and the wall 12 of the rotating part 10, - the shaft 214 of the screw 210 is received in the hole of the centering washer 231 and in the orifice 14 of the wall 12 of the rotating part 10, and - the nut 220 cooperates with the rod 214 of the screw 210 and is arranged to bear against the wall 12 of the rotating part.

[0007] The balancing of the rotating part 10 of the assembly 2 is achieved by varying either the number of centering washers 231 or the thickness of the centering washer 231 of the balancing device 200.

[0008] However, as illustrated in [Fig. 2], during the operation of the turbomachine, due to the presence of residual play between the shaft 214 of the screw 210 and the hole in the centering washer 231, the centering washer 231 can slide radially. The misalignment of the centering washer 231 with respect to the orifice 14 in the wall 12 of the rotating part causes the balancing mass to move and thus the center of gravity of the assembly 2 to shift. Furthermore, the misalignment of the centering washer 231 with respect to the screw 210 results in shear stresses on the screw 210, causing damage to the shaft 214 of the screw 210, or even its breakage. Summary of the invention

[0009] The invention offers a solution to the problems mentioned above, by proposing an assembly comprising a rotating part and a balancing device for the rotating part having a particular architecture.

[0010] A first aspect of the invention relates to an assembly comprising a rotating part having a wall delimited by a first surface and a second surface, and an orifice passing through the wall from the first surface to the second surface. The assembly further comprises at least one balancing device comprising a screw having a head and a shank received in the orifice of the rotating part; at least one centering washer with axis XI maintained between the head of the screw and the second surface of the wall of the rotating part and extending axially between a first end surface and a second end surface, and comprising an axial hole receiving the shank of the screw; and a nut cooperating with the shank of the screw and arranged against the first surface of the wall of the rotating part.

[0011] The centering washer of the balancing device comprises a first cylindrical portion of external diameter DI received in the orifice of the wall of the rotating part and extending axially from the first end surface to an external bearing surface pressed against the second surface of the wall, the hole opening onto the first end surface; a second cylindrical portion of external diameter D2 greater than DI and extending axially from the external bearing surface to the second end surface, the first and second portions being coaxial; and a cylindrical receiving housing arranged in the second portion (236), from the second end surface, and opening coaxially into the hole of the centering washer.

[0012] The assembly according to the invention, thanks to the particular geometry of the balancing device's centering washer, ensures that the balancing washer remains centered within the opening in the wall of the rotating part. Indeed, in the assembled position of the balancing device on the rotating part of the assembly: the presence of a first portion of the centering washer inside the opening in the wall of the rotating part allows for radial locking of the centering washer relative to the rotating part; and the presence of a second portion of the centering washer, having an external diameter greater than that of the first portion, allows for axial locking of the centering washer relative to the rotating part.

[0013] Such an architecture of the balancing device makes it possible to maintain good balance of the assembly by centering the center of gravity of the assembly and thus prevent any shearing phenomenon of the screw of the balancing device.

[0014] Advantageously, the receiving housing for the centering washer of the balancing device has an internal diameter D3 substantially equal to the external diameter DI of the first portion of the centering washer. This feature allows the centering washers to be nested together so that the first portion of one centering washer is received in the receiving housing of the second portion of another centering washer.

[0015] Preferably, the receiving housing for the centering washer of the balancing device has an axial length L3 substantially equal to an axial length L1 of the first portion of the centering washer. This feature allows the centering washers to be nested together such that the first end surface of the first portion is in contact with an internal bearing surface of the receiving housing for the second portion of another centering washer.

[0016] Advantageously, the receiving housing for the centering washer of the balancing device extends axially along only a part of the second portion of the centering washer.

[0017] Advantageously, the head of the screw is received in the receiving housing of one of at least one centering washer of the balancing device.

[0018] Preferably, the receiving housing for the centering washer of the balancing device receiving the head includes an internal bearing surface so that the head of the screw is in contact with the internal bearing surface.

[0019] Advantageously, the balancing device comprises at least two centering washers, a first washer and a second washer. The first portion of the first washer of the balancing device is received in the opening in the wall of the rotating part, and the first portion of the second washer is received in the housing receiving the first washer, and the head of the screw is received in the receiving housing of the second washer.

[0020] The presence of several centering washers makes it possible to increase the mass of the balancing device and to adjust the balance of the assembly by correcting the imbalance of the rotating part.

[0021] Preferably, the first and second washers each have a strictly different mass m relative to each other, this allows the imbalance of the rotating part to be corrected precisely.

[0022] Advantageously, the first and second centering washers each have a strictly different total axial length L0 relative to each other. The presence of centering washers of different lengths makes it possible to obtain centering washers of different masses and thus adjust the balance of the assembly and correct the imbalance of the rotating part with precision.

[0023] A second aspect of the invention relates to a method of balancing an assembly according to the first aspect of the invention in which the balancing is carried out by selecting a total mass of the balancing device corresponding to the sum of the mass of the screw, the nut and one or more centering washers.

[0024] Such a balancing method, in the case of use on a test bench, makes it possible to modify the balance in situ during the test and thus minimize downtime during the test.

[0025] A third aspect of the invention relates to a turbomachine comprising at least one assembly according to the first aspect of the invention.

[0026] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0027] Other advantages and features of the invention will become apparent from the following description, illustrated by the figures in which: - Fig. 1, already described, is a partial schematic view of an assembly comprising a rotating part and a balancing device according to the prior art comprising a centering washer in a position centered relative to the rotating part; - Fig. 2, already described, is a partial schematic view of an assembly comprising a rotating part and a balancing device according to the prior art comprising a centering washer in a position offset from the rotating part; - Fig. 3 is a partial schematic view of an assembly comprising a rotating part and a balancing device according to the invention comprising a centering washer; - Fig. 4 is a schematic view of a centering washer of the balancing device according to Figure 3; - Fig. 5 is a partial schematic view of an assembly comprising a rotating part and a balancing device according to the invention comprising two identical centering washers; - Fig. 6 is a partial schematic view of an assembly comprising a rotating part and a balancing device according to the invention comprising two centering washers different from each other. DETAILED DESCRIPTION

[0028] An example of an embodiment of a turbomachine assembly according to the invention is described in detail below, with reference to the accompanying drawings. This example illustrates the features and advantages of the invention.

[0029] Unless otherwise specified, the same element appearing on different figures has a unique reference.

[0030] For the purposes of understanding the invention, the radial, tangential, and axial orientations will be adopted according to the RTA frame shown in the figures, whose tangent T and axial A axes extend in a horizontal plane along the orientation shown in the figures. The axial axis A is parallel to an X axis of a rotating part of the assembly.

[0031] In the following description, the terms "upstream surface", "upstream end surface" and "upstream portion" correspond respectively to the terms "first surface", "first end surface" and "first portion" and the terms "downstream surface", "downstream end surface" and "downstream portion" correspond respectively to the terms "second surface", "second end surface" and "second portion".

[0032] According to an example of the assembly illustrated in the figures, an "upstream" element towards a "downstream" element is oriented along the direction of the axial axis A.

[0033] Fig. 3 illustrates an assembly 2 comprising a rotating part 10 and at least one balancing device 200. The rotating part 10 with axis of rotation X0 comprises a wall 12 delimited by an upstream surface 12A and a downstream surface 12B, and an orifice 14 passing through the wall 12 from the upstream surface 12A to the downstream surface 12B.

[0034] The balancing device 200 comprises: - a screw 210 comprising a head 212 and a shaft 214, - at least one 230 centering washer for axis XI, and - a 220 nut.

[0035] As shown in isolation in [Fig. 4], the centering washer 230 extends axially between an upstream end surface 230A and a downstream end surface 230B, defining its total length LO. The centering washer 230 includes an axial hole 232 of internal diameter DO opening onto the upstream end surface 230A.

[0036] The centering washer 230 is divided into two portions along the axis XI: - an upstream portion 234 cylindrical of external diameter D1, and - a downstream portion 236 cylindrical of external diameter D2, the upstream portions 234 and downstream portions 236 being coaxial.

[0037] Since the external diameter Dl of the upstream portion 234 is less than the external diameter D2 of the downstream portion 236, an external bearing surface 235 is formed between the upstream portions 234 and downstream portions 236. Consequently, the upstream portion 234 extends axially from the upstream end surface 230A to the external bearing surface 235 along an axial length Ll, and the downstream portion 236 extends axially from the external bearing surface 235 to the downstream end surface 230B along an axial length L2.

[0038] The centering washer 230 includes a cylindrical receiving housing 240 of internal diameter D3 arranged in the downstream portion 236, extending from the downstream surface 230B and opening coaxially into the hole 232 of the centering washer 230. Since the internal diameter D0 of the hole 232 is smaller than the internal diameter D3 of the receiving housing 240 of the upstream portion 234, an internal bearing surface 242 is formed between the hole 232 and the receiving housing 240, defining the bottom of the receiving housing 240. Consequently, the receiving housing 240 extends axially from the internal bearing surface 242 to the downstream end surface 230B over an axial length L3, and the hole 232 extends axially from the internal bearing surface 242 to the upstream end surface 230A over a length axial L0-L3.

[0039] The receiving housing 240 of the centering washer 230 extends axially along only a part of the downstream portion 236 of the centering washer 230 along its axial length L3 strictly less than the axial length L2 of the downstream portion 236.

[0040] As shown in [Fig.4], the internal diameter D3 of the receiving housing 240 is substantially equal to the external diameter Dl of the upstream portion 234 of the centering washer 230. In addition, the axial length L3 of the receiving housing 240 is substantially equal to the axial length Ll of the upstream portion 234 of the centering washer 230.

[0041] Advantageously, the 200 nut is a floating rivet nut.

[0042] According to a first embodiment of the balancing device 200 as shown in [Fig.3], the balancing device 200 comprises a single centering washer 230.

[0043] In the assembled position of the balancing device 200 on the rotating part 10 of the assembly 2, according to the first embodiment: - the screw 210, the centering washer 230 and the nut 220 are axially aligned along axis XI, - the centering washer 230 is held between the head 212 of the screw 210 and the wall 12 of the rotating part 10 so that the external bearing surface 235 of the centering washer 230 is in contact with the downstream surface 12B of the wall 12 of the rotating part 10, - the head 212 of the screw 210 is received in the receiving recess 240 of the centering washer 230, bearing against the internal bearing surface 242 of the receiving recess 240, - the shaft 214 of the screw 210 is received in the hole 232 of the centering washer 230 and in the orifice 14 of the wall 12 of the rotating part 10, and - the nut 220 is tightened with the shank 214 of the screw 210 and is arranged to bear against the upstream surface 12A of the wall 12 of the rotating part 10.

[0044] The particular geometry of the centering washer 230 of the balancing device 200 allows both the insertion of the upstream portion 230A of the centering washer 230 into the orifice 14 of the wall 12 of the rotating part 10 and the insertion of the head 212 of the screw 210 into the receiving housing 240 of the centering washer 230. In addition, the tightening of the screw 210 - nut 220 ensures axial locking of the centering washer 230 relative to the rotating part 10.

[0045] As shown in Figures 5 and 6, the balancing device 200 may include several centering washers 230 so as to increase the mass of the balancing device 200.

[0046] According to a second and third embodiment of the balancing device 200 as shown in Figures 5 and 6, the balancing device 200 comprises two centering washers 230 nested one inside the other.

[0047] According to the second example illustrated in [Fig.5], the balancing device 200 comprises a first washer 230-1 and a second washer 230-2 that are geometrically identical to each other.

[0048] In the assembled position of the balancing device 200 on the rotating part 10 of the assembly 2, according to the second embodiment: - screw 210, first washer 230-1, second washer 230-2 and nut 220 are axially aligned along axis XI, - the first washer 230-1 is held between the wall 12 of the rotating part 10 and the second washer 230-2 so that the external bearing surface 235-1 of the first washer 230-1 is in contact with the downstream surface 12B of the wall 12 of the rotating part 10, - the second washer 230-2 is held between the first washer 230-1 and the head 212 of the screw 210 so that its upstream portion 234-2 is received in the receiving housing 240-1 of the first washer 230-1 and that the external bearing surface 235-2 of the second washer 230-2 is in contact with the downstream end surface 230B-1 of the first washer 230-1, - the head 212 of the screw 210 is received in the receiving housing 240-2 of the second washer 230-2, bearing against the internal bearing surface 242-2 of the receiving housing 240-2, - the shank 214 of the screw 210 is received in the holes 232-1, 232-2 of the first and second washers 230-1, 230-2 and in the orifice 14 of the wall 12 of the rotating part 10, and - the nut 220 is tightened with the shank 214 of the screw 210 and is arranged to bear against the upstream surface 12A of the wall 12 of the rotating part.

[0049] The specific geometry of the centering washer 230 of the balancing device 200 also allows several centering washers 230 to be nested together by inserting the upstream portion 234 of one centering washer 230 into the receiving recess 240 of the downstream portion 236 of another centering washer 230. Thanks to the dimensions of each centering washer 230, namely diameters DI and D3 and axial lengths L1 and L3, there is no play between the centering washers 230 when they are nested together. Furthermore, the screw 210 - nut 220 tightening ensures axial locking of the centering washers 230 relative to the rotating part 10.

[0050] According to the embodiment of the balancing device 200 shown in [Fig. 5], the first and second washers 230-1, 230-2 are geometrically identical with respect to each other. Consequently, each centering washer 230 of the balancing device 200 has the same total length L0, i.e., the same axial lengths L1, L2 and L3 as well as the same diameters D1, D2 and D3.

[0051] The assembly of the balancing device 200 according to the third embodiment on the rotating part 10 of the assembly 2 ([Fig.6]) is identical to that of the assembly device 200 according to the second embodiment described previously ([Fig.5]).

[0052] According to this second embodiment, the centering washers 230 of the same balancing device 200 can be made of different materials, that is- i.e. having a different density, so as to obtain centering washers 230 of different mass m.

[0053] According to the third example illustrated in [Fig.6], the balancing device 200 comprises a first washer 230-1 and a second washer 230-3 having a different geometry relative to each other.

[0054] The second washer 230-3 has a total length L0-3 greater than the total length L0-1 of the first washer 230-1, such that the axial length L2-3 of the downstream portion 236-3 of the second washer 230-3 is greater than the axial length L2-1 of the downstream portion 236-1 of the first washer 230-1. Furthermore, the first and second washers 230-1, 230-3 have the same axial length L1 of their upstream portion 234-1, 234-3 and the same axial length L3 of their receiving housing 240-1, 240-3 in order to ensure the interlocking of the centering washers 230 with respect to each other.

[0055] According to this third embodiment, the use of centering washers 230 of different total length L0 makes it possible to obtain centering washers 230 of different mass m in the same balancing device 200.

[0056] A balancing method for the assembly 2 allows the balancing to be achieved by selecting a total mass of the balancing device 200 corresponding to the sum of the mass of the screw 210, the nut 220 and one or more centering washers 230.

[0057] The selection of the mass of the balancing process can be carried out by: - ​​adding or removing at least one centering washer 230 from the balancing device 200, and / or, - the variation in the material constituting at least one centering washer 230 of the balancing device 200, and / or - the variation in the total length L0 of at least one centering washer 230 of the balancing device 200.

[0058] An assembly 2 comprising a balancing device 200 according to the invention ensures the axial and radial maintenance of each centering washer 230 in a position centered inside the orifice 14 of the wall 12. In addition, such a balancing device 200 allows, during the balancing process, for its total mass to be adjusted either by adding or removing at least one centering washer 230 due to their particular geometry allowing them to be nested within each other, or by varying the material or the total length L0 of at least one centering washer 230.

Claims

1. Demands Set (2) comprising: - a rotating part (10) comprising: • a wall (12) delimited by a first surface (12A) and a second surface (12B), and • an opening (14) passing through the wall (12) from the first surface (12A) to the second surface (12B), and - at least one balancing device (200) comprising: • a screw (210) comprising a head (212) and a shaft (214) received in the orifice (14) of the rotating part (10), • at least one centering washer (230) with axis XI maintained between the head (212) of the screw (210) and the second surface (12B) of the wall (12) of the rotating part (10) and extending axially between a first end surface (230A) and a second end surface (230B), and comprising an axial hole (232) receiving the shank (214) of the screw (212), and • a nut (220) cooperating with the shank (214) of the screw (210) and arranged against the first surface (12A) of the wall (12) of the rotating part (10), characterized in that the centering washer (230) of the balancing device (200) comprises: - a first cylindrical portion (234) of external diameter DI received in the orifice (14) of the wall (12) of the rotating part (10) and extending axially from the first end surface (230A) to an external bearing surface (235) pressed against the second surface (12B) of the wall (12), the hole (232) opening onto the first end surface (230A), - a second cylindrical portion (236) of diameter external D2 greater than the external diameter DI of the first portion (234) and extending axially from the external support surface (235) to the second end surface (230B), the first and second portions (234, 236) being coaxial, and - a cylindrical receiving housing (240) arranged in the second portion (236), from the second end surface (230B), and opening coaxially into the hole (232) of the centering washer (230), the receiving housing (240) having an internal diameter D3 substantially equal to the external diameter DI of the first portion (234) of the centering washer (230).

2. Assembly (2) according to claim 1, characterized in that the receiving housing (240) of the centering washer (230) of the balancing device (200) has an axial length L3 substantially equal to an axial length L1 of the first portion (234) of the centering washer (230).

3. Assembly (2) according to any one of the preceding claims, characterized in that the receiving housing (240) of the centering washer (230) of the balancing device (200) extends axially along only a part of the second portion (236) of the centering washer (230).

4. Assembly (2) according to any one of the preceding claims, characterized in that the head (212) of the screw (210) is received in the receiving housing (240) of one of at least one centering washer (230) of the balancing device (200).

5. Assembly (2) according to claim 4, characterized in that the receiving housing (240) of the centering washer (230) of the balancing device (200) receiving the head (212) comprises an internal bearing surface (242), and in that the head (212) of the screw (210) is in contact with the internal bearing surface (242).

6. Assembly (2) according to any one of the preceding claims, characterized in that the balancing device (200) comprises at least two centering washers (230) of which the first washer (230-1) and the second washer (230-2), and in that: - the first portion (234) of the first washer (230-1) of the balancing device (200) is received in the orifice (14) of the wall (12) of the rotating part (10), - the first portion (234) of the second washer (230-2) is received in the receiving housing (240-1) of the first washer (230-1), and - the head (212) of the screw (210) is received in the receiving housing (240-2) of the second washer (230-2).

7. Assembly (2) according to claim 6, characterized in that the first and second washers (230-1, 230-2) each have a strictly different mass m with respect to each other.

8. Method for balancing a rotating part (10) of an assembly (2) according to any one of the preceding claims, characterized in that the balancing is achieved by selecting a total mass of the balancing device (200) corresponding to the sum of the mass of the screw (210), the nut (220) and one or more centering washers (230).

9. Turbomachine, characterized in that it comprises at least one assembly (2) according to any one of claims 1 to 7.

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