Balancing weight for a rotor of an aircraft turbine engine

Abstract

The invention relates to a balancing weight (30) for a rotor of an aircraft turbine engine, the balancing weight (30) being able to be removably attached to a rotor of an aircraft turbine engine, characterized in that the balancing weight (30) has an elongate overall shape along an axis of elongation (Y) and comprises two hooks (32, 34), one at each of its two longitudinal ends, these two hooks (32, 34) being oriented axially towards each other and being able to move in axial translation along the axis of elongation (Y) such that they can be brought closer to each other in order to clamp an element of the rotor between them, and moved away from each other in order to remove the weight (30) from this element.

Description

[0001] DESCRIPTION

[0002] TITLE: BALANCING WEIGHT FOR AN AIRCRAFT TURBOMACHINE ROTOR

[0003] Technical field of the invention

[0004] The present invention relates in particular to a balancing weight for an aircraft turbomachine rotor, as well as a method of mounting this weight.

[0005] Technical background

[0006] The technical background includes in particular documents DE-A1 -10 2016 210454, CA-A1 -2 503 039, FR-A1-3 106 156 and EP-A1 -0 474 560.

[0007] An aircraft turbomachine has rotors which must be balanced in rotation to avoid or reduce unbalance in particular.

[0008] This is the case, for example, with a turbine rotor. A turbine rotor comprises a succession of axial stages (along the axis of circulation of the gas flows) arranged one behind the other. Each stage comprises a rotor wheel with blades and a stator distributor with blades. The wheel is set in rotation opposite the corresponding distributor.

[0009] In the present application, upstream and downstream are defined with respect to the normal flow direction of the air flows (from upstream to downstream) through the turbomachine. The term "axis of the turbomachine" refers to the axis of rotation of the main rotor of the turbomachine. The axial direction corresponds to the direction of the axis of the turbomachine, and a radial direction is a direction perpendicular to the axis of the turbomachine and intersecting this axis. Similarly, an axial plane is a plane containing the axis of the turbomachine, and a radial plane is a plane perpendicular to this axis. The adjectives "inner" or "internal" and "outer" or "external" are used with reference to a radial direction so that the inner part of an element is, in a radial direction, closer to the axis of the turbomachine than the outer part of the same element.The stacking axis of a blade is the axis perpendicular to the axis of the turbomachine, which passes through the center of gravity of the innermost section of the blade blade (i.e., the section closest to the axis of the turbomachine). Typically, a turbomachine blade comprises a blade extending along the stacking axis of the blade, between the radially inner and outer tips of the blade.

[0010] A wheel conventionally comprises an annular disc centered on the axis of rotation and on which a plurality of blades are fixed.

[0011] An example of a blade is shown in Figure 1. A blade of this type is described in patent document FR-A1-3 079 847. This blade 10 comprises a blade 16 extending along the stacking axis X of the blade, between the radially inner 10a and outer 10b ends of the blade 10. At its inner end 10a, the blade 10 comprises a lower platform 19 and a root 12 by which it is fixed to a disc (not shown in Figure 1).

[0012] At its outer end 10b, the blade 10 has a heel 14. The heel 14 comprises a platform 20 externally delimiting the flow path of the gas circulating between the blades 16, and having opposite lateral edges 21, 22. The platform 20 comprises an upstream portion 24 called the “upstream spoiler” and a downstream portion 28 called the “downstream spoiler”. The heel 14 also comprises upstream 31 and downstream 32 sealing lips extending radially outwards from the outer or outer face of the platform 20. Each of the lateral edges 21, 22 of the platform has, between the upstream 31 and downstream 32 lips, a substantially “U” shaped profile. In the case of other blades, this profile may take the form of a “Z” or a “V”, for example.

[0013] Balancing a rotor or rotor element generally involves removing or adding material to the rotor or rotor element in order to correct its dynamic rotational behavior. It is easier to add material and a simple way is to mount one or more balancing weights on the rotor or rotor element. For example, there are balancing weights that are fixed to the rotor wheel mounting flanges. In practice, such a weight includes a hole for one of the flange mounting screws to pass through. This type of weight can be removed but is generally permanently attached to the rotor or rotor element since it is rare and unnecessary to remove it.

[0014] In some cases, balancing weights may be mounted on a rotor or rotor component temporarily, for example to perform tests, such as certification tests. These tests may involve reducing an unbalance or, on the contrary, causing an unbalance. These weights are attached to a rotor or rotor component in a more confined and difficult-to-access environment. Furthermore, the available areas for fixing these balancing weights are few in number and are not particularly suitable, which risks causing movement or vibration of the weights, or even accidental disassembly of the weights.

[0015] There is therefore a need for a balancing weight which can solve all or part of the problems and disadvantages of the prior art.

[0016] Summary of the invention

[0017] The invention thus provides a balancing weight for an aircraft turbomachine rotor, the balancing weight being capable of being removably attached to an aircraft turbomachine rotor, characterized in that the balancing weight has a generally elongated shape along an elongation axis and comprises two hooks respectively at its two longitudinal ends, these two hooks being oriented axially towards each other and being movable in axial translation along the elongation axis so as to be able to be brought closer to each other to grip an element of the rotor between them, and to be moved away from each other to remove the weight from this element. The weight is designed to facilitate its mounting in and on a rotor, as well as its dismantling. This allows the weight to be used for balancing a rotor, temporarily if necessary.The weight is configured to be hooked onto the rotor or rotor element and for this purpose comprises two hooks or claws which face each other and are intended to grip between them a part of the rotor or rotor element. The design and use of the weight according to the invention are therefore relatively simple. The weight according to the invention may comprise one or more of the following features, taken in isolation from one another or in combination with one another:.

[0018] - the weight comprises a central body, each of the hooks being connected to the central body so as to be movable in axial translation along the axis of elongation with respect to this body; the central body can be configured to have a predetermined balancing mass; naturally, it is the total mass of the weight, and not only of the central body, which is taken into account for the balancing of a rotor;

[0019] - each of the hooks is connected to the body by a sliding or slide connection;

[0020] - the weight further comprises at least one elastic member which forces the hooks to move axially closer together;

[0021] - each of the hooks has a bearing surface on the aforementioned element, this bearing surface being inclined relative to said elongation axis;

[0022] - the support surfaces of the hooks are parallel;

[0023] - the flyweight is made of a carbon or graphite-based material; this reduces the risk of wear of the material of the rotor element on which the flyweight is mounted, because the material of the flyweight is relatively fragile and brittle and will deteriorate more quickly than that of the rotor element, which is generally metallic, for example by friction.

[0024] The present invention also relates to an assembly comprising a rotor blade for an aircraft turbomachine, and a weight as described above. The blade may comprise a blade, one end of which is connected to a root and an opposite end of which is connected to a platform, this platform comprising two opposite edges which are located respectively on the side of a leading edge and a trailing edge of the blade, the platform further comprising an internal surface located on the side of the blade,

[0025] Preferably, the weight is pressed against the internal surface and its hooks rest respectively on the two opposite edges of the platform.

[0026] The weight is preferably located on the extrados side of the blade.

[0027] The weight preferably has its axis of elongation parallel to a chord of the blade.

[0028] The present invention also relates to a rotor for an aircraft turbomachine, comprising a rotor disk and several assemblies as described above, the roots of the blades of the assemblies being mounted in cells of the external periphery of the rotor disk.

[0029] The present invention also relates to a method for mounting a weight as described above, on a rotor element such as a rotor blade, this method comprising the following steps: a) mounting the weight at the end of a tool suitable for mounting the weight, this tool comprising a distal end for gripping the weight, and a proximal end for manipulating the tool, the proximal end of the tool comprising an actuator, and the distal end of the tool comprising a mechanism which is connected to the actuator and which makes it possible to control the approaching or moving away of the hooks from each other by acting on the actuator, b) positioning the weight at the rotor element by means of the tool, and c) controlling the approaching of the hooks by means of the actuator so that the hooks grip the rotor element.The method according to the invention may comprise one or more of the following features or steps, taken in isolation from one another or in combination with one another:

[0030] - the rotor element is a rotor blade, step b) consisting of positioning the weight on an internal surface of a platform of the blade, and step c) consisting of controlling the bringing together of the hooks so that they bear respectively on two opposite edges of the platform of the blade located respectively on the side of a leading edge and a trailing edge of a blade of the blade;

[0031] - steps b) and c) are carried out on a rotor comprising several rotor blades mounted on the outer periphery of a rotor disc, or in a rotor module comprising several rotors of this type which are integral in rotation with each other.

[0032] Brief description of the figures

[0033] The invention will be better understood and other details, characteristics and advantages of the invention will appear more clearly on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

[0034] [Fig. 1] Figure 1 is a schematic perspective view of a rotor blade,

[0035] [Fig.2] Figure 2 is a partial schematic sectional view of a turbomachine module, and in particular of a turbine,

[0036] [Fig.3] Figure 3 is a schematic view of the platform of a rotor blade, on which a balancing weight according to the invention is mounted, [Fig.4] Figure 4 is a schematic perspective view of the balancing weight of Figure 3,

[0037] [Fig.5] Figure 5 is another schematic side view of the balance weight of Figure 3, [Fig.6] Figure 6 is a schematic perspective view of the balance weight of Figure 3, and a tool for mounting this weight, and illustrates a method of mounting the weight, and

[0038] [Fig.7] Figure 7 is a partial schematic perspective view of the balance weight of Figure 3.

[0039] Detailed description of the invention

[0040] Figure 1 has been described in the above.

[0041] Figures 2 to 5 illustrate a first embodiment of a balancing weight 30 for an aircraft turbomachine rotor.

[0042] The flyweight 30 is shown alone in Figures 4 and 5 and is shown mounted on a rotor in Figures 2 and 3.

[0043] In the example shown, which is not limiting, the rotor is a rotor blade 10 or a rotor comprising such a rotor blade 10 or a turbomachine module, such as a turbine, comprising such a rotor blade 10.

[0044] The rotor blade 10 is of the type illustrated in FIG. 1 and comprises a blade 16 extending along the stacking axis X of the blade, between the radially inner 10a and outer 10b ends of the blade 10. At its inner end 10a, the blade 10 comprises a lower platform 19 and a root 12 by which it is fixed to a disc 13.

[0045] The disc 13 comprises at its periphery cells 15 oriented substantially parallel to the axis of the disc 13 and arranged alternately with teeth 17 of the disc 13. Each blade 10 is held on the disc 13 by insertion of the root 12 into one of the cells 15 of the disc 13. The root 12 is held radially by shape cooperation by the teeth 17 of the disc 13.

[0046] At its outer end 10b, the blade 10 has a heel 14.

[0047] The heel 14 comprises a platform 20 externally delimiting the flow path of the gas circulating between the blades 16, and having opposite lateral edges 21, 22 (figure 3). The platform 20 comprises an upstream part 24 called “upstream spoiler” and having an upstream edge 24a and a downstream part 28 called “downstream spoiler” and having a downstream edge 28a. The upstream edge 24a is located on the side of the leading edge 16a of the blade 16, and the downstream edge 28a is located on the side of the trailing edge 16b of the blade 16. As seen in figure 2, the blade 16 has a chord C (which is a virtual line that connects its leading edge 16a to its trailing edge 16b in a rectilinear manner) which is inclined relative to the upstream 24a and downstream 28a edges.

[0048] The heel 14 also comprises upstream 31 and downstream 32 sealing lips extending radially outwards from the outer surface 20b of the platform 20 (figure 2). Each of the lateral edges 21, 22 of the platform has, in particular between the upstream 31 and downstream 32 lips, a substantially “U”, “Z” or “V” shaped profile for example.

[0049] The weight 30 is capable of being removably fixed to a rotor and in particular to the platform 20 of the rotor blade 10.

[0050] The weight 30 has a general elongated shape along an elongation axis Y and comprises two hooks 32, 34 respectively at its two longitudinal ends.

[0051] The two hooks 32, 34 are oriented axially towards each other and are movable in axial translation along the elongation axis Y so as to be able to be brought closer to each other to grip between them an element of the rotor such as the platform 20, and to be moved away from each other to dismantle the weight 30 from this element.

[0052] In the example shown in Figures 1 and 2, it can be seen that the weight 30 is mounted on the inner or internal surface 20a of the platform 20 which is located on the side of the blade 16, and therefore on the side opposite the wipers 31, 32.

[0053] The weight 30 can be pressed radially against this internal surface 20a.

[0054] The hooks 32, 34 of the weight 30 bear respectively on the two opposite edges 24a, 28a of the platform 30. Each of the hooks 32, 34 may have a general L or U shape and may comprise a hooking edge 35 oriented towards the other hook and intended for example to bear on the external surface 20b of the platform 20 located on the side of the lips 31, 32.

[0055] The weight 30 can be mounted on the side of an extrados of the blade 16, as illustrated in Figure 3.

[0056] The weight 30 may have its elongation axis Y which is parallel to the chord C of the blade 16 and which is therefore inclined relative to the aforementioned edges 24a, 28a as visible in figure 3.

[0057] As can be better seen in Figures 4 and 5, the weight 30 may comprise a central body 36, each of the hooks 32, 34 being connected to the central body 36 so as to be movable in axial translation along the axis of elongation Y relative to this body 36.

[0058] Each of the hooks 32, 34 can be connected to the body 36 by a sliding or slide connection system 38.

[0059] The weight 30 may further comprise at least one elastic member 40 which forces the hooks 36 to move axially closer together.

[0060] Each of the hooks 32, 34 may have a bearing surface 32a, 34a which is inclined or perpendicular to the elongation axis Y. These bearing surfaces 32a, 34a of the hooks 32, 34 may be parallel to each other. The weight 30 is preferably made of a carbon or graphite-based material.

[0061] Figures 6 and 7 illustrate a method of mounting the balance weight 30 described above.

[0062] The mounting method comprises the following steps: a) mounting the weight 30 at the end of a tool 50, b) positioning the weight 30 at the rotor element by means of the tool 50, and c) controlling the bringing together of the hooks 32, 34 so that the hooks 32, 34 grip the rotor element. The tool 50 is specifically adapted for mounting the weight 30 according to the invention. This tool 50 comprises a distal end 50a for gripping the weight 30, and a proximal end 50b for manipulating the tool.

[0063] The proximal end 50a of the tool 50 comprises an actuator 52 such as a lever, a trigger or the like.

[0064] The distal end 50b of the tool 50 comprises a mechanism 54 which is connected to the actuator 52 and which makes it possible to control the hooks 32, 34 moving towards or away from each other by acting on the actuator 52. The actuator 52 is connected to the mechanism 54 by a linkage or the like. As can be seen in FIGS. 6 and 7, the weight 30 may comprise a housing 42 in which the distal end 50a of the tool 50 is intended to be engaged, and in which the sliding or slide connection system 38 is accessible. The mechanism 54 of the tool 50 is configured to apply a force to this system 38 and to move the hooks 32, 34 away from or towards each other, depending on the intervention made by an operator on the actuator 52.

[0065] Step c) is thus carried out by means of the actuator 52. An operator who manipulates the tool 50 acts on this actuator 52 to cause, by means of the mechanism 54, a bringing together or a moving away of the hooks 32, 34. In the aforementioned case where the hooks are urged axially towards each other, the actuation of the tool 50 can be used to move the hooks 32, 34 away from each other.

[0066] When the rotor element is a rotor blade 10 as described above, step b) consists of positioning the weight 30 on the internal surface 20a of the platform 20 of the blade 10, and step c) consists of controlling the bringing together of the hooks 32, 34 so that they bear respectively on the two opposite edges 24a, 28a of the platform 20 of the blade 10.

[0067] Steps b) and c) can be carried out on a rotor comprising several rotor blades 10 mounted on the outer periphery of a rotor disc 13, or in a rotor module comprising several rotors of this type which are rotationally fixed to each other.

[0068] In the case where several weights 30 are used to balance a rotor, these weights 30 may be identical and therefore have identical masses, or may on the contrary differ from each other in their masses. Advantageously, the masses of the weights 30 may vary depending on the shape and dimensions of their central bodies 36. For example, the central bodies 36 of the weights 30 may be more or less thick to vary the masses of the weights 30. In the absence of central bodies 36, the hooks 30, 32 of the weights could be thickened in certain places for example to vary the masses of the weights 30.

Claims

CLAIMS 1. Balancing weight (30) for an aircraft turbomachine rotor, the balancing weight (30) being capable of being removably attached to an aircraft turbomachine rotor, characterized in that the balancing weight (30) has a generally elongated shape along an elongation axis (Y) and comprises two hooks (32, 34) respectively at its two longitudinal ends, these two hooks (32, 34) being oriented axially towards each other and being movable in axial translation along the elongation axis (Y) so as to be able to be brought together to grip an element of the rotor between them, and to be moved away from each other to remove the weight (30) from this element.

2. Weight (30) according to claim 1, in which it comprises a central body (36), each of the hooks (32, 34) being connected to the central body (36) so as to be movable in axial translation along the axis of elongation (Y) relative to this body (36).

3. A weight (30) according to claim 2, wherein each of the hooks (32, 34) is connected to the body by a sliding or slide connection (38).

4. Weight (30) according to one of the preceding claims, in which it further comprises at least one elastic member (40) which forces the hooks (32, 34) to move axially closer together.

5. Weight (30) according to one of the preceding claims, in which each of the hooks (32, 34) has a surface (32a, 34a) for bearing on the aforementioned element, this bearing surface (32a, 34a) being inclined relative to said axis of elongation (Y).

6. Weight (30) according to the preceding claim, in which the bearing surfaces (32a, 34a) of the hooks (32, 34) are parallel.

7. Weight (30) according to one of the preceding claims, in which it is made of a carbon or graphite-based material.

8. Assembly comprising a rotor blade (10) for an aircraft turbomachine, and a weight (30) according to one of the preceding claims, the blade (10) comprising a blade (16) one end of which is connected to a root (12) and one opposite end of which is connected to a platform (20), this platform (20) comprising two opposite edges (24a, 28a) which are located respectively on the side of a leading edge (16a) and a trailing edge (16b) of the blade (16), the platform (20) further comprising an internal surface (20a) located on the side of the blade (16), the weight (30) being pressed against the internal surface (20a) and its hooks (32, 34) bearing respectively on the two opposite edges (24a, 28a) of the platform (20).

9. Assembly according to claim 7, in which the weight (30) is located on the side of an extrados of the blade (16).

10. Assembly according to claim 7 or 8, in which the weight (30) has its axis of elongation (Y) which is parallel to a chord (C) of the blade (16).

11. Rotor for an aircraft turbomachine, comprising a rotor disk (13) and several assemblies according to one of claims 7 to 9, the roots (12) of the blades (10) of the assemblies being mounted in cells (15) of the external periphery of the rotor disk (13).

12. Method for mounting a weight (30) according to one of claims 1 to 6, on a rotor element such as a rotor blade (10), this method comprising the following steps: a) mounting the weight (30) at the end of a tool (50) adapted for mounting the weight (30), this tool comprising a distal end (50a) for gripping the weight (30), and a proximal end (50b) for manipulating the tool (50), the proximal end (50b) of the tool (50) comprising an actuator (52), and the distal end (50a) of the tool (50) comprising a mechanism (54) which is connected to the actuator (52) and which allows to control the approaching or moving away of the hooks (32, 34) from each other by acting on the actuator (52), b) positioning the weight (30) at the level of the rotor element by means of the tool (50), and c) controlling the approaching of the hooks (32, 34) by means of the actuator (52) so that the hooks (32, 34) grip the rotor element.

13. Method according to claim 12, in which the rotor element is a rotor blade (10), step b) consisting of positioning the weight (30) on an internal surface (20a) of a platform (20) of the blade (10), and step c) consisting of controlling the bringing together of the hooks (32, 34) so ​​that they bear respectively on two opposite edges (24a, 28a) of the platform (20) of the blade (10) located respectively on the side of a leading edge (16a) and a trailing edge (16b) of a blade (16) of the blade (10).

14. Method according to claim 12 or 13, wherein steps b) and c) are carried out on a rotor comprising a plurality of rotor blades (10) mounted on the outer periphery of a rotor disc (12), or in a rotor module comprising a plurality of such rotors which are rotationally fixed to each other.

Images