Guide device for an aircraft turbine engine
Patent Information
- Application Number
- EP2024712118
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-03-03
- Filing Date
- 2024-02-23
- Publication Date
- 2026-01-14
AI Technical Summary
Existing guiding devices for aircraft turbomachines, particularly those with a metal body and plastic guide shoe, face issues with the guide shoe coming loose due to shearing forces, leading to potential loss and requiring device removal for repair, which can disrupt valve synchronization.
A guiding device with a metal body and a guide pad featuring studs that are both glued and crimped onto the body, providing a double fixation mechanism to prevent separation, ensuring the guide pad remains attached even if it comes loose, using through holes and protruding studs that are crimped to increase retention.
The double fixation mechanism significantly reduces the risk of the guide pad separating from the metal body, ensuring reliable operation and preventing disruptions to valve kinematics and synchronization, allowing for in-situ maintenance and reducing repair needs.
Smart Images
Figure FR2024050239_12092024_PF_FP_ABST
Abstract
Description
[0001] DESCRIPTION
[0002] TITLE: GUIDE DEVICE FOR AN AIRCRAFT TURBOMACHINE
[0003] Technical field of the invention
[0004] The present invention relates to the general field of aeronautics. It relates more particularly to a guidance device for an aircraft turbomachine, an aircraft turbomachine comprising one or more guidance devices, and a method of manufacturing this device.
[0005] Technical background
[0006] The technical background includes in particular documents US-A1- 2014 / 050567, US-A1 -2012 / 195755, US-A1 -2009 / 038739 and US-A1- 2004 / 062641.
[0007] In the present application, the term "guiding device" means a device capable of guiding a moving element, in particular by sliding or friction. The element is thus intended to slide or rub on the guiding device during its movements.
[0008] A turbomachine can include different types of guide devices. For example, devices are known for guiding a control ring for a VBV (Variable Bleed Valve) system or for a VSV (Variable Stator Valve) system.
[0009] A control ring extends around an annular casing of the turbomachine and guide devices are attached to the casing and serve to guide the control ring during its movements around and / or along the casing.
[0010] In a VBV system, the control ring is connected to wastegates. In a VSV system, the control ring is connected to variable-pitch stator vanes.
[0011] Although the following description details a VBV system, the invention is not limited to this application.
[0012] Among the existing technologies of guide devices, the invention relates to a guide device comprising a metal body and a guide pad glued to the metal body and on which the movable element such as the control ring is able to slide.
[0013] The metal body is generally fixed to a casing and comprises at least one fixing lug comprising an orifice configured to receive a screw or the like.
[0014] The guide shoe is made of plastic material and is glued to the body. This shoe has a free sliding guide surface.
[0015] The control ring is made to slide on the guide shoe during its movements. The shoe facilitates the sliding of the ring and ensures, thanks to a relatively low coefficient of friction, good sliding with the ring.
[0016] This guidance device technology is relatively simple, inexpensive, and fulfills its purpose. However, experience in use has shown a limitation in its use regarding the guide pad.
[0017] There is indeed a risk that the guide pad could detach and separate from the body, which could lead to the loss of the guide pad in the engine. Indeed, the relative movements between the ring and the guide pad generate shear forces at the interface between the pad and the body which eventually cause partial and then total debonding of the guide pad. To date, due to the limited accessibility of the devices, the debonding of the guide pads observed under the wing cannot be repaired at this level of inspection. Thus, when debonding exceeds the admissible criteria, there is a loss of support of the ring on the guide device, which risks modifying the synchronization of the kinematics and therefore impacting the opening and closing of the valves. The guide device must then be removed for repair.
[0018] The innovation aims to provide a solution to resolve this technical problem and provide a more reliable solution than the current solution.
[0019] Summary of the invention
[0020] The invention relates to a guide device for an aircraft turbomachine, comprising: - a metal body comprising at least one fixing lug comprising an orifice configured to receive a screw or the like, this metal body comprising a first surface,
[0021] - a guide pad which is made of a plastic or composite material, this pad comprising a first surface glued to said first surface of the body and a second opposite surface which is free and which is configured to form a sliding guide surface, characterized in that said metal body comprises through holes which open onto the first surface of the body, and in that said guide pad comprises studs which project from said first surface of the pad and which are engaged and crimped respectively in the holes of said body. The guide pad of the guide device according to the invention is crimped onto the body in addition to being glued thereto. There is therefore a double fixing of the pad to the body which greatly limits the risk of one becoming detached from the other. Even in the event of the pad becoming detached, the guide pad remains secured to the body thanks to the crimping.This crimping is obtained using studs on the skate and engaged in holes in the body.
[0022] The guidance device according to the invention may also comprise one or more of the following features, taken alone or in combination with each other:
[0023] - each of the studs passes through one of said holes and comprises a free end deformed by crimping and bearing on a second surface of the body opposite its first surface;
[0024] - the free end is deformed by melting said guide pad material;
[0025] - the deformed free end of each stud has a diameter or transverse dimension greater than the diameter or transverse dimension of the remainder of this stud and of the hole crossed by this stud;
[0026] - the guide pad is made of PTFE;
[0027] - the number of plots is between 3 and 10; this number is for example chosen according to the space available;
[0028] - the number of plots is three or four:
[0029] -- the plots are not aligned;
[0030] -- the blocks are aligned two by two; - the skate has a curved or arched shape;
[0031] -- the guide shoe is formed from a single piece with its studs;
[0032] -- the guide pad is in the form of a flat or curved plate comprising two main surfaces, the studs projecting from one of these main surfaces which form said second surface of the pad, and the other of these main surfaces forming the first surface of the pad;
[0033] -- each of the studs has a length greater than a length or depth of the holes so that the free end of each of the studs protrudes from the hole crossed by this stud.
[0034] The present invention also relates to an aircraft turbomachine, comprising an annular casing, a control ring extending around the casing, and guide devices as described above which are fixed to the casing and interposed between the casing and the control ring, the control ring being able to slide on the guide surfaces of the devices.
[0035] In one embodiment of the invention, the casing comprises through openings for the passage of gas, and the control ring is connected to discharge valves moved by the control ring from a first position for closing these openings to a position for releasing these openings.
[0036] The present invention also relates to a method of manufacturing a device as described above, in which it comprises the following steps: a) producing the metal body and the guide shoe, this guide shoe comprising projecting studs on its first surface which have a constant diameter or transverse dimension over their entire length, b) gluing the first surface of the body and / or the first surface of the guide shoe, c) mounting the guide shoe on the body by engaging the studs of the guide shoe in the holes of the body and by applying the first surface of the guide shoe to the first surface of the body, and d) crimping the studs so that their free ends have a diameter or transverse dimension greater than the diameter or transverse dimension of the rest of these studs.
[0037] The method according to the invention may also comprise one or more of the following features, taken alone or in combination with each other:
[0038] - the method comprises, between steps a) and b), a step i) of shaping and in particular curving the guide shoe;
[0039] - step d) is carried out by heating and melting the free ends of the pads;
[0040] - step d) is carried out by applying a distal end of a heating tool, such as a soldering iron, to the free end of each of the pads, this distal end comprising a flat surface which is intended to bear on the body and which comprises a cylindrical housing for receiving this free end;
[0041] -- the distal end has a generally cylindrical shape;
[0042] -- before step d), each of the studs has a length which protrudes from the hole which it passes through, which is greater than a depth of said housing;
[0043] -- said housing has an internal diameter which is greater than the diameter of the studs before step d).
[0044] Brief description of the figures
[0045] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:
[0046] [Fig.1] Figure 1 is a schematic axial sectional view of an aircraft turbomachine;
[0047] [Fig. 2] Figure 2 is a half schematic view in axial section of a compressor and an intermediate casing of an aircraft turbomachine, this intermediate casing being equipped with a VBV system;
[0048] [Fig. 3] Figure 3 is an enlarged schematic view of the VBV system of Figure 2;
[0049] [Fig. 4] Figure 4 is a schematic perspective view of a VBV system for an aircraft turbomachine; [Fig. 5] Figure 5 is a schematic perspective view of a guidance device according to one embodiment of the invention;
[0050] [Fig. 6] Figure 6 is a schematic front view of the metal body of the guide device of Figure 5;
[0051] [Fig. 7] Figure 7 is a schematic perspective view of the metal body of the guide device of Figure 5;
[0052] [Fig. 8] Figure 8 is a schematic perspective view of the guide shoe of the guide device of Figure 5, before assembly or bending;
[0053] [Fig. 9] Figure 9 is a schematic side view of the guide shoe of the guide device of Figure 5, after assembly or bending and before crimping;
[0054] [Fig. 10] Figure 10 is a schematic front view and transparency of the guide device of Figure 5, after a step of mounting the guide shoe on the metal body;
[0055] [Fig. 11] Figure 11 is a schematic perspective view of the guide device of Figure 5, after the step of mounting the guide shoe on the metal body;
[0056] [Fig. 12 Figure 12 is a partial schematic perspective view of the guide device of Figure 5 and a crimping tool, and illustrates another step in the manufacture of this device;
[0057] [Fig. 13] Figure 13 is a schematic perspective view of the tool of Figure 12;
[0058] [Fig. 14] Figure 14 is a schematic sectional view of a guide device and a heating crimping tool, and illustrates a step in manufacturing the device; and
[0059] [Fig. 15] Figure 15 is a schematic perspective and transparency view of a guiding device, after the crimping step.
[0060] Detailed description of the invention
[0061] In the present invention, and generally, the terms "upstream", "downstream", "axial" and "axially" are defined with respect to the circulation of gases in a turbomachine and here along the longitudinal axis X (and even from left to right in Figure 1) of this turbomachine. Similarly, the terms "radial", "internal" and "external" are defined with respect to a radial axis Y perpendicular to the longitudinal axis X and with respect to the distance from the longitudinal axis X.
[0062] As illustrated in Figure 1, which is a schematic axial sectional view of a dual-flow or dual-spool turbomachine 10, such a turbomachine generally comprises, from upstream to downstream in the direction of gas flow, a low-pressure compressor 12, a high-pressure compressor 14, an annular combustion chamber 16, a high-pressure turbine 18 and a low-pressure turbine 20, which define a flow path for a primary gas flow F1.
[0063] The rotor of the high-pressure turbine 18 is integral with the rotor of the high-pressure compressor 14 so as to form a high-pressure body, while the rotor of the low-pressure turbine 20 is integral with the rotor of the low-pressure compressor 12 so as to form a low-pressure body. The rotor of each turbine drives the rotor of the associated compressor in rotation about the longitudinal axis 24 of the turbomachine under the effect of the thrust of the gases coming from the combustion chamber 16.
[0064] In such a turbomachine 10, an intermediate casing 26 is usually interposed between the low pressure compressor 12, located upstream, and the high pressure compressor 14, located downstream. The intermediate casing 26 has a generally annular shape.
[0065] In the case of dual-flow turbomachines, which comprise a fan 28 shrouded by a nacelle 30 to generate a secondary flow F2, the intermediate casing 26 generally comprises arms 34 crossing the flow path of this secondary flow F2.
[0066] Figure 2 illustrates a simplified view of an intermediate casing 26 on which discharge valves 48 are mounted at the hub 36 of the intermediate casing 26. This hub 36 comprises two coaxial annular shells, respectively internal 38 and external 44, and two radial walls or flanges, respectively upstream 40 and downstream 42, connecting the internal 38 and external 44 shells. The internal shell 38 delimits the external part relative to the axis 24 of the primary flow space, or primary vein, of the primary flow F1 of the turbomachine. Furthermore, this hub 36 is equipped with an annular row of discharge valves 48, one of which is visible in section in Figure 2. In this figure appears more specifically the door 50 of the valve 48, which is pivotally mounted around an axis 51, so as to be movable between an open position and a closed position of a corresponding opening 60 formed in the internal ferrule 38 of the hub 36.
[0067] Each of the discharge air inlet openings 60, of substantially parallelepiped shape, is associated with a discharge valve 48 intended for regulating the flow rate of the high pressure compressor 14.
[0068] A system for controlling the opening and closing of the discharge valves 48, commonly referred to as a VBV system, is more visible in FIG. 3 and comprises a control ring 62 for controlling the opening and closing of the discharge valves 48 depending on the operating conditions of the turbomachine. This ring 62 is centered on the longitudinal axis 24 of the turbomachine 10 and placed in the space located outside the shell 38.
[0069] The movement of the control ring 62 is carried out by actuators (not shown) which are also located outside the shell 38. The rotation of the control ring 62 actuates actuating devices driving the discharge doors 50. An actuating device is associated with each discharge door 50 and comprises a connecting rod 64, one end of which is connected to the discharge door 50 and an opposite end of which is connected by a bellcrank 66 to the control ring 62, so as to transform the movement of the ring 62 around and / or along the axis 24 into a pivoting and opening / closing movement of the door 50. Each bellcrank 66 is articulated around a substantially radial axis. The opening of each valve 48 causes the discharge of an air flow (arrow 52 in dotted lines in Figure 2) into the annular space delimited by the ferrules 38, 44 and the radial walls 40, 42.
[0070] The downstream radial wall 42 delimits, for its part, the internal part relative to the axis X of the flow space in the secondary vein, of the secondary flow F2. The wall 42 comprises an annular row of orifices 54 for the passage of the discharge air flows 52, towards the downstream. As seen in FIG. 2, discharge ducts 56 are mounted downstream of the intermediate casing 26 and are each intended to guide an air flow 52 caused by the opening of a discharge valve 48, the air flow being guided from the outlet of the orifices 54 to the flow vein of the secondary flow F2.
[0071] Figures 3 and 4 show devices 70 for guiding the control ring 62 during its movements.
[0072] The guide devices 70 are fixed to the intermediate casing 26 and in particular to the internal ferrule 38 in the example shown. The guide devices 70 are interposed between the ferrule 38 and the ring 62 which can slide on the guide devices 70 during its movements.
[0073] Figures 5 and following illustrate an embodiment of a guidance device 70 according to the invention.
[0074] This guide device 70 essentially comprises two parts or two pieces, namely a metal body 72 and a guide shoe 74 attached and glued to the metal body 72.
[0075] The metal body 72 is shown alone in Figures 6 and 7.
[0076] The metal body 72 is fixed to the casing 26 by means of screws or the like such as bolts or rivets. It therefore comprises one or more orifices 75 for the passage of these screws or the like.
[0077] The holes 75 may be formed in one or more fixing lugs 76 of the body 72
[0078] In the example shown, the body 72 comprises a generally rectangular plate having two parallel long sides and two parallel short sides. Two L-shaped tabs 78 project from one of these long sides, and the other long side comprises a flange 80 or is bent to form a tab 76, which extends along the entire length of this long side. Each of the tabs 78 comprises an orifice 75 and the flange 80 comprises two orifices 75. Each of the short sides may further comprise stiffeners 82 as seen in the drawings.
[0079] The body 72 comprises two opposite surfaces 72a, 72b. In the example shown, these surfaces 72a, 72b are those of the aforementioned plate and each have a generally rectangular shape. These surfaces 72a, 72b are advantageously smooth and may be flat or slightly curved. In the latter case, the surface 72a is convexly curved and the surface 72b is concavely curved.
[0080] As seen in the drawings, the body 72 comprises through holes 84 which here open onto the surfaces 72a, 72b.
[0081] The number of holes 84 is three here although this number is not limiting.
[0082] The 84 holes are not aligned along the same straight line here.
[0083] The guide shoe 74 is shown alone in Figures 8 and 9.
[0084] The guide shoe 74 is fixed to the metal body 72 by gluing and crimping. The guide shoe 74 is glued to the surface 72a of the body 72 and partially or completely covers this surface 72a.
[0085] In the example shown, the guide shoe 74 comprises a generally rectangular plate having two parallel long sides and two parallel short sides. The dimensions of the plate of the shoe 74 are preferably identical or close to those of the plate of the body 72.
[0086] The guide shoe 74 comprises two opposite surfaces 74a, 74b. In the example shown, these surfaces 74a, 74b are those of the aforementioned plate and each have a generally rectangular shape.
[0087] These surfaces 74a, 74b are advantageously smooth and can be flat or slightly curved. In the latter case, the surface 74a is convexly curved and the surface 74b is concavely curved (see figure 9).
[0088] The surface 74a is intended to remain free and forms the sliding surface of the control ring 62 in the aforementioned application.
[0089] The surface 74b is intended to be glued to the surface 72a of the body and to cover it.
[0090] The guide shoe 74 comprises projecting studs 86 which are intended to be engaged and crimped into the holes 84 of the metal body 72. The studs 86 project from the surface 74b of the shoe 74.
[0091] The studs 86 have positions and dimensions that allow them to be engaged in the holes. It is therefore understood that, in the example shown, the studs 86 are three in number and are not aligned. The studs 86 may have a generally cylindrical shape before crimping, they thus each have a constant diameter D1 over their entire length L1. The length L1 of the studs is preferably greater than the thickness E1 of the body 72 and in particular of its plate so that the studs 86 of the pad 74 pass completely through the holes 84 of the body 72.
[0092] The guide shoe 74 is preferably made of PTFE (polytetrafluoroethylene). Figures 10 to 14 illustrate steps of a manufacturing method according to the invention and Figure 15 illustrates the guide device 70 obtained at the end of this method.
[0093] It can be seen in Figure 15 that each of the studs 86 passes through one of the holes 84 and comprises a free end deformed by crimping and bearing on the surface 72b of the body 72. As will be described below, the free end is preferably deformed by melting the material of the guide pad 74. The deformed free end of each stud 86 has a diameter D2 greater than the diameter D1 of the remainder of this stud 86 and of the hole 84 passed through by this stud, which ensures the retention of the guide pad 74 with respect to the metal body 72.
[0094] An embodiment of a method for manufacturing a guide device 70 will now be described with reference to FIGS. 10 to 13.
[0095] The method comprises a first step a) of producing the metal body 72 and the guide shoe 74.
[0096] The metal body 72 is for example made by casting or by machining. The guide shoe 74 is for example made by molding. The holes 84 can be obtained directly during the manufacture of the body 74, or afterwards for example by drilling.
[0097] The method may comprise a following step i) of shaping the guide shoe 72. This shaping is preferably a folding or curvature of the guide shoe 74 and in particular of its plate, as illustrated in FIG. 9, so that it has a curvature similar to that of the body 72 and in particular of its surface 72a.
[0098] The method comprises a second step b) of gluing the surface 72a of the body 72 and / or the surface 74b of the pad 74. The glue is for example of the epoxy or polyurethane type although this is not limiting. The method comprises a third step c) of mounting the guide pad 74 on the body 72 by engaging the studs 86 of the guide pad 74 in the holes 84 of the body 72 and by applying the surface 74b of the guide pad 74 to the surface 72a of the body 72. The assembly illustrated in Figures 10 and 11 is then obtained in which the free ends of the studs 86 preferably project from the surface 72b of the body.
[0099] The method comprises a fourth step d) of crimping the pads 86 so that their free ends have a diameter D2 greater than the diameter D1 of the rest of these pads.
[0100] Step d) is preferably carried out by heating and melting the free ends of the pads 86. Alternatively, it could be carried out by plastic deformation of these free ends.
[0101] As illustrated in Figures 12 to 14, step d) can be carried out by applying a distal end 90a of a heating tool 90, such as a soldering iron, to the free end of each of the pads 86. The distal end 90a preferably comprises a flat surface 92 which is intended to bear on the surface 72b of the body 72 and which comprises a cylindrical housing 94 for receiving the free end of the pad 96.
[0102] In the example shown, the distal end 90a has a generally cylindrical shape and the flat surface 92 is circular or annular, the housing 94 being centered on this surface 92.
[0103] During step d), the free end of the stud 86 is engaged in the housing 94 and is heated beyond the melting point (approximately 327°C for PTFE) of the material of the pad 74. The tool 90 is moved until its surface 92 bears on the body 72 so as to fold the softened material onto the surface 72b of the body and thus deform the free end of the stud 86. It is therefore understood that the depth P1 of the housing 94 is preferably less than the length L2 of each stud 86 which projects from the surface 72b of the body. After crimping, the length L2' of each stud which projects from the surface 72b is substantially equal to the depth P1 of the housing 94. To allow the deformation of the free end, it is also understood that the diameter D3 of the housing 94 is preferably greater than the diameter D1 of the stud 86 before crimping. After crimping, the free end of the stud has a diameter D2 equivalent to the diameter D3 of the housing 94.
Claims
CLAIMS 1. Guidance device (70) for an aircraft turbomachine, comprising: - a metal body (72) comprising at least one fixing lug (76) comprising an orifice (75) configured to receive a screw or the like, this metal body (72) comprising a first surface (72a), - a guide pad (74) which is made of a plastic or composite material, this pad (74) comprising a first surface (74b) glued to said first surface (72a) of the body (72) and a second opposite surface (74a) which is free and which is configured to form a sliding guide surface, characterized in that said metal body (72) comprises through holes (84) which open onto the first surface (72a) of the body (72), and in that said guide pad (74) comprises studs (86) which project from said first surface (84b) of the pad (84) and which are engaged and crimped respectively in the holes (84) of said body (72).
2. Device (70) according to claim 1, in which each of the studs (86) passes through one of said holes (84) and comprises a free end deformed by crimping and bearing on a second surface (72b) of the body (72) opposite its first surface (72a).
3. Device (70) according to claim 2, wherein the free end is deformed by melting said material of the guide shoe (74).
4. Device (70) according to claim 2 or 3, in which the deformed free end of each stud (86) has a diameter (D2) or a transverse dimension greater than the diameter (D1) or the transverse dimension of the remainder of this stud (86) and of the hole (84) crossed by this stud (86).
5. Device (70) according to one of the preceding claims, in which the guide pad (74) is made of PTFE.
6. Device (70) according to one of the preceding claims, in which the number of pads (86) is between 3 and 10.
7. Device (70) according to claim 6, wherein the number of pads (86) is three or four.
8. Device (70) according to one of the preceding claims, in which the pad (74) has a curved or arched shape.
9. Aircraft turbomachine (10), comprising an annular casing (26), a control ring (62) extending around the casing (26), and guide devices (70) according to one of the preceding claims which are fixed to the casing (26) and interposed between the casing (26) and the control ring (62), the control ring (62) being able to slide on the guide surfaces of the devices (70).
10. Turbomachine (10) according to claim 9, in which the casing (26) comprises through openings (60) for the passage of gas, and the control ring (62) is connected to discharge valves (48) moved by the control ring (62) from a first position for closing these openings (60) to a position for releasing these openings (60).
11. A method of manufacturing a device (70) according to one of claims 1 to 8, wherein it comprises the following steps: a) producing the metal body (72) and the guide shoe (74), this guide shoe (74) comprising studs (86) projecting from its first surface (72a) which have a diameter (D1) or a transverse dimension constant over their entire length, b) gluing the first surface (72a) of the body (72) and / or the first surface (74b) of the guide shoe (74), c) mounting the guide shoe (74) on the body (72) by engaging the studs (86) of the guide shoe (74) in the holes (84) of the body (72) and by applying the first surface (74b) of the guide shoe (74) to the first surface (72a) of the body (72), and d) crimping the studs (86) so that their free ends have a diameter (D2) or a transverse dimension greater than the diameter (D1) or the transverse dimension of the rest of these pads (86).
12. Method according to claim 11, in which it comprises, between steps a) and b), a step i) of shaping and in particular curving the guide shoe (74).
13. Method according to claim 11 or 12, in which step d) is carried out by heating and melting the free ends of the pads (86).
14. Method according to claim 13, in which step d) is carried out by applying a distal end of a heating tool (90), such as a soldering iron, to the free end of each of the pads (86), this distal end comprising a flat surface (92) which is intended to bear on the body (72) and which comprises a cylindrical housing (94) for receiving this free end.