Tool for machining an annular wear layer of a fan case of a turbine engine of an aircraft and machining method using such a tool

Abstract

The invention relates to a tool (20) for machining an annular wear layer (10b) of a casing (3) of a fan (1) of a turbine engine, comprising: - a central centring body (30) configured to be attached to a fan disc (2) of the turbine engine; - a machining tool (50) connected to the central body (30) and comprising at least one machining device (51) configured to come into contact with the wear layer; and - a first motor (52) for rotating the machining device (51), characterised in that the central body (30) comprises or carries a profile cam (70) comprising a cam profile (72) which depends on the desired surface profile of the machined wear layer (10b).

Description

Technical Field

[0001] This invention relates to a tool for machining an annular wear-resistant layer on the fan casing of an aircraft turbine engine and a machining method using such a tool. Background Technology

[0002] The technical background includes documents WO-A1-2016 / 2023141, GB-A-2240735, EP-A1-3017898, and WO-A1-2023 / 062302. The primary function of the fan casing assembled on the aircraft turbine engine is to ensure its stability in the event of debris ingestion or fan blade loss.

[0003] Some secondary functions of the fan housing are to ensure the mechanical continuity of forces and torques between the air inlet handle and the intermediate housing section to allow for the attachment of duct panels such as the upstream acoustic housing, the cylinder of the wear-resistant support, and the downstream acoustic panel.

[0004] Other functions of the fan housing include allowing the attachment of equipment and supports to meet fire and leakage specifications, and ensuring current continuity to prevent lightning strikes.

[0005] For example, on a turbine engine, up to eighteen fan blades can be mounted opposite a wear-resistant layer. This wear-resistant layer is typically made of a solid-color porous material, which breaks down during operation as the fan blades come into contact with it to ensure optimal pneumatic ducting.

[0006] When not in operation, a certain amount of clearance is required to ensure that the fan blades can be installed in the fan housing.

[0007] During operation, the inertia of the fan discs, including all the fan blades, causes the discs to separate to fill the gaps between components and also to form optimal aerodynamic ducts.

[0008] To form this pneumatic duct, the fan blades come into contact with the wear-resistant layer and break it as needed.

[0009] During operation, some wear-resistant porous materials may separate from the rest of the surface when they break.

[0010] This is not the only source of wear-resistant layer breakage, as the fan may suck in foreign objects during operation, which could damage the wear-resistant surface.

[0011] These missing surfaces or irregularities, about a few micrometers in size, on one side of the continuous wear-resistant layer opposite the blades must be repaired to avoid performance loss, appearance problems, or the risk of further degradation if they are not restored to consistency.

[0012] To repair the annular wear layer, it is known to disassemble the housing containing the wear layer as a whole, positioning the housing in an environment (e.g., a workshop) that allows the wear layer to be processed and repaired. Disassembling the housing, transporting it to the workshop, and then performing the reverse operation is inefficient and expensive, and requires a specialized workshop located near the housing.

[0013] Therefore, it is necessary to improve the efficiency and repeatability of processing the wear-resistant layer of the fan casing of aircraft turbine engines.

[0014] The applicant has already proposed a tool for machining annular wear-resistant layers on a fan housing in document FR-A1-3117390.

[0015] This invention is an improvement on this tool, particularly in terms of improving processing quality. Summary of the Invention

[0016] Therefore, the present invention provides a tool for machining an annular wear-resistant layer on a fan housing of an aircraft turbine engine, the tool being configured to be at least partially housed within the housing, and comprising: - A centering body configured to be attached to the fan disk of the turbine engine, enabling it to rotate about the fan disk's axis of rotation. - A machining tool, connected to a central body, and including at least one machining device configured to contact the wear-resistant layer, and - A first motor for driving the rotation of the processing device. The central body includes or carries a template cam, the template cam including a cam profile that depends on the desired surface profile of the processed wear-resistant layer, and the processing tool is movable relative to the template cam and configured to follow the cam profile, so that the processing device processes the wear-resistant layer according to the cam profile.

[0017] Therefore, particularly due to its central body, the tool can be positioned directly inside the fan housing, regardless of the housing's position. Thanks to the template cam selected according to its cam profile, the tool according to the invention can precisely machine the wear-resistant layer. Machining the wear-resistant layer according to this cam profile significantly improves the machining quality, especially the dimensional and geometrical consistency of the machined wear-resistant layer.

[0018] In this application, the term "surface profile" refers to the profile (i.e., general shape) of a surface's cross-section. The surface under consideration is the inner annular surface of the wear-resistant layer, and when considering the cross-section of the wear-resistant layer, the profile of the surface is therefore the general shape of the surface.

[0019] Tools according to the invention may include one or more of the following features, either individually or in combination: -The machining device is a ball end mill; - The tool includes a second motor for driving the machining tool to rotate about the axis of rotation; -The motor, or each motor, is a brushless electric motor; - The template cam is removably and interchangeably mounted on the central body; - The template cam includes a flat plate in which an elongated through slot is formed, the slot including a longitudinal edge that defines a desired surface profile, i.e., the axial cross-sectional shape of the inner annular surface of the wear-resistant layer; the use of the slot is advantageous because the slot can guide better. - The plate has a roughly parallelepiped shape; - The plate extends in a plane passing through the axis of rotation; - The processing tool includes a follower, such as a roller, which engages in a slot and cooperates with the longitudinal edge by sliding or rolling; the follower engages in the slot such that the follower cannot move away from the longitudinal guide edge, which ensures optimal guidance; - The template cam is clamped to the center body by a mounting bracket and / or clamping screws; - The processing device is housed in a cover for protecting and containing chips and dust, the cover being supported by a tool; - The cover is connected to a suction pump for chips and dust via a hose; The tool also includes a measuring tool connected to the central body and comprising at least one probe configured to be supported on the layer, the measuring tool being, for example, diametrically opposite the machining tool relative to the axis of rotation; - The central body is equipped with a position-adjustable counterweight to limit the force required to drive the central body to rotate about the axis of rotation; - The tool also includes a template extension configured to be mounted on both sides of the wear-resistant layer and axially clamped onto the wear-resistant layer; - The slot is slightly wider than the diameter of the follower or roller, that is, the width is about 101% to 120% of the diameter.

[0020] The present invention also relates to a method for machining an annular wear-resistant layer on a fan housing of an aircraft turbine engine using a tool according to any one of the preceding claims, the method comprising the following steps: a) Determine the desired surface profile of the processed wear-resistant layer. b) Select a template cam and removably mount the template cam on the center body, the template cam including a cam profile corresponding to the surface profile, and c) The wear-resistant layer is machined according to the cam profile. Attached Figure Description

[0021] Other features and advantages of the invention will become apparent from the following detailed description. For understanding these other features and advantages, reference is made to the accompanying drawings, in which: [ Figure 1 ] Figure 1 This is a schematic diagram of the axial cross-section of the fan of an aircraft turbine engine. [ Figure 2 ] Figure 2 This is a schematic perspective view of the fan housing. [ Figure 3 ] Figure 3 This is a schematic side view of the fan housing and machining tool according to the present invention. [ Figure 4 ] Figure 4 This is a schematic axial sectional view of a machining tool according to the invention inserted into a portion of the fan disc. [ Figure 5 ] Figure 5 This is a schematic perspective view of the central body of the machining tool according to the present invention. [ Figure 6 ] Figure 6 This is a schematic axial sectional view of the extension of the machining tool according to the present invention, and [ Figure 7 ] Figure 7 This is a schematic perspective view of the machining tool and the template cam of the machining tool according to the present invention. [ Figure 8 ] Figure 8 This is another schematic perspective view of the machining tool and the template cam of the machining tool according to the present invention. [ Figure 9 ] Figure 9 This is another schematic perspective view of the template cam of the machining tool according to the present invention. [ Figure 10 ] Figure 10 This is a schematic cross-sectional perspective view of the template cam of the machining tool according to the present invention. [ Figure 11 ] Figure 11 Another schematic cross-sectional perspective view of a part of the machining tool according to the invention, and [ Figure 12 ] Figure 12 This is a schematic perspective view of the counterweight of the template cam of the machining tool according to the present invention. Detailed Implementation

[0022] Figure 1 This is a partial view of the fan of an aircraft turbine engine.

[0023] Typically, a turbine engine consists of a fan, one or more compressors, a combustion chamber, one or more turbines, and nozzles for injecting combustion gases that exit one or more turbines, from upstream to downstream (i.e., along the direction of airflow).

[0024] The fan 1 includes a blade disk 2, which is surrounded by a fan housing 3, also known as a retaining housing, because its function is to retain the blade in the event of blade breakage or debris entering the fan.

[0025] from Figure 2 It can be seen that the fan housing 3 has a roughly cylindrical shape with a rotation axis A.

[0026] The fan housing includes annular retaining flanges 3' at each of its axial ends. These flanges 3' are used to secure the housing 3 to the annular wall of the turbine engine nacelle or the shell portion of the downstream intermediate housing.

[0027] Such as Figure 2 As shown, the wear-resistant material layer 10b exists inside the fan housing 3 by rotating within the fan housing 3.

[0028] Therefore, the fan housing 3 extends around the fan impeller disk 2. Thus, the fan housing includes an inner cylindrical surface on which an annular wear-resistant material layer 10b is disposed.

[0029] An annular wear-resistant material layer 10b (hereinafter referred to as wear layer 10b) extends around one of the impellers 2a and over a short radial distance as the impeller disk 2 rotates. The impeller 2a can continuously rub against the wear layer 10b during operation, and wear down the wear layer 10b through friction.

[0030] This allows for optimization of the radial clearance between the blade 2a and the surrounding fan housing 3, thereby limiting gas leakage at the radially outer tip or end of the blade and thus optimizing the performance of the turbine engine.

[0031] The wear-resistant layer 10b can be supported by a solid or honeycomb structure support cylinder 4. This cylinder 4 is typically riveted or screwed onto the fan housing 3.

[0032] The machining tool 20 according to the present invention is in Figure 3 (The exterior of housing 3) and Figure 4 (The interior of housing 3) is shown. This tool 20 is configured to process the wear-resistant layer 10b of housing 3 of fan 1, and in particular to repair the wear-resistant layer 10b.

[0033] For this purpose, tool 20 includes: - A central body 30 for centering or even fixing to the fan disk 2 of the turbine engine, the central body 30 being designed to be rotatable about the rotation axis A of the fan disk 2. - A machining tool 50, which is connected to the central body 30, and includes at least one machining device, such as a rotary milling cutter 51, configured to contact the wear-resistant layer 10b. - First motor 52 for driving the milling cutter 51 to rotate.

[0034] Tool 20 may also include a measuring tool 40 connected to the central body 30 and including at least one probe 41 configured to be supported on the wear-resistant layer 10b. The measuring tool is rotatable about axis A on the central body 30.

[0035] Tool 20 may also include a second motor 32 for rotating at least the measuring tool 40 and the machining tool 50 about axis A. Alternatively, this rotation may be manually performed by an operator about axis A.

[0036] The machining tool 50 and the measuring tool 40 are connected to the central body 30, for example, via a shaft 90. The radially extending dimension of this shaft is substantially smaller than the inner diameter of the housing 3 to allow the tool 20 to be axially inserted into the housing 3. In particular, the machining tool 50 and the measuring tool 40 are substantially diametrically opposed to each other with respect to axis A.

[0037] The tool 20 can be brought into the interior of the housing 3 by means of a bracket 60 (e.g., the bracket described in document WO-A1-2023 / 062302). The tool 20 can have a weight between 100 kg and 150 kg.

[0038] Once the tool 20 is centered relative to the housing 3, it is inserted into the housing 3 along axis A. Once the tool 20 is inserted into the housing 3, it is secured to the fan disc 2 by means of a fixing device 31 including the central body 30.

[0039] Tool 20 also includes displacement devices 58 for translating (i.e., radially) the machining tool 50 relative to axis 90. These displacement devices 58 enable the milling cutter 51 to be positioned in contact with the wear-resistant layer, allowing for adjustment of the depth of cut and machining.

[0040] At least one of the first motor 52 and the second motor 32 is an electric motor, and preferably a brushless motor, to reduce noise pollution during operation and improve operator comfort during processing.

[0041] Each of the first motor 52 and the second motor 32 can be controlled independently. Therefore, the first motor 52 and the second motor 32 can rotate at two different speeds. Then, the measuring tool 40 and the machining tool 50 can be fully rotated while the probe is in contact with the wear-resistant layer to measure the thickness of the wear-resistant layer without rotating the milling cutter 51.

[0042] The milling cutter 51 can be housed in a cover 53 for protecting and containing chips and dust, which is carried by the machining tool 50.

[0043] The cover 53 is connected via a hose 54 to a suction pump (not shown) for chips and dust. Suction is used to prevent dust from being inhaled by the operator. The cover 53 is, for example, transparent, so that the milling cutter 51 and the wear-resistant layer 10b can be seen during machining.

[0044] Figure 5 The figures below illustrate various parts of a more specific embodiment of the tool 20 according to the invention.

[0045] Figure 5 The central body 30 of the tool is shown, which has a generally annular shape and is supported here by the aforementioned bracket 60.

[0046] Figure 6 Template extensions 62 and 64 are shown, which are designed to be mounted on both sides of the wear-resistant layer 10b and axially clamped onto the wear-resistant layer 10b.

[0047] These extensions 62 and 64 are used to repair the wear-resistant layer after the wear-resistant layer 10b has been processed. The extensions 62 and 64 form templates for applying new wear-resistant materials.

[0048] A straight scraper 66 is guided in or on extensions 62, 64 to apply a new wear-resistant material with a controlled excess thickness.

[0049] Figures 7 to 9 The central body 30 is shown to include or support a template cam 70, which includes a cam profile 72 that depends on the desired surface profile of the processed wear-resistant layer 10b.

[0050] The machining tool 50 is movable relative to the template cam 70 and is configured to follow the cam profile 72, such that the milling cutter 51 machines the wear-resistant layer 10b according to the cam profile 72.

[0051] Preferably, the template cam 70 is removably mounted on the central body 30 such that the template cam 70 can be selected according to its cam profile 72, thereby adapting the cam profile 72 to the fan housing 3 to be processed. The wear-resistant layer 10b of multiple engines or reference fan housings of the same engine may have different surface profiles. Preferably, the number of available template cams 70 is equal to the number of different surface profiles of these fan housings 3. Therefore, it should be understood that the operator must select the template cam 70 with the desired surface profile of the wear-resistant layer 10b and mount the template cam on the tool 20.

[0052] The template cam 70 can be clamped onto the center body 30 by mounting bracket 74 and / or clamping screw 76.

[0053] In the example shown, the template cam 70 includes a plate 80 in which an elongated through slot 82 is formed. The slot, in the sense of the invention, is characterized by being surrounded and defined by a continuous outer peripheral edge. Therefore, the slot is formed at a distance from the edge of the plate 80. The slot 82 includes a longitudinal edge 84 that defines the desired surface profile, i.e., the axial cross-sectional shape of the inner annular surface of the wear-resistant layer 10b.

[0054] For example, plate 80 has a generally parallelepiped shape. Preferably, plate 80 extends in a plane passing through axis of rotation A.

[0055] The processing tool 50 may include a follower 91, such as a roller, which engages in the slot 82 and cooperates with the longitudinal edge 84 of the slot 82 by sliding or rolling.

[0056] Preferably, the slot 82 is slightly wider than the diameter of the follower or roller.

[0057] Figure 11 A micrometer-level adjustment system 92 for setting the machining depth of cut is shown, as well as a positioning system 93 using a tapered surface and a fixing screw.

[0058] Figure 12 The diagram shows that the central body 30 can be equipped with a position-adjustable counterweight 94 to limit the force required to rotate the central body 30 about the axis of rotation A. When not in use, the tool 20 can be stored in a crate, which can also be used to transport the tool 20.

[0059] The present invention also relates to a method for processing the annular wear-resistant layer 10b of the housing 3 of the fan 1 of an aircraft turbine engine using the aforementioned tool 20, the method comprising the following steps: a) Determine the desired surface profile of the processed wear-resistant layer 10b. b) Select the template cam 70 and removably mount the template cam 70 onto the center body. The template cam 70 includes a cam profile corresponding to the surface profile, and c) The wear-resistant layer 10b is machined according to the cam profile.

[0060] During processing, the pipes in the housing may be protected by a shield or similar object, such as the shield described, for example, in document WO-A1-2023 / 062302.

[0061] This invention offers many advantages, including: - Improve operator ergonomics, especially regarding noise levels. - The dimensional consistency of the wear-resistant layer 10b can be directly detected during processing using probe 41. - Faster repair times to minimize engine downtime. - Greater repeatability of the repair -For a high level of safety for operators -Due to the interchangeability of template cams, the tool's adaptability to different surface profile configurations, etc.

Claims

1. A tool (20) for machining an annular wear-resistant layer (10b) of a housing (3) of a fan (1) of an aircraft turbine engine, said tool (20) being configured to be at least partially housed within said housing (3), and comprising: - A centering body (30) is configured to be attached to the fan disk (2) of the turbine engine, and is rotatably movable about the rotation axis (A) of the fan disk (2). - A processing tool (50), said processing tool being connected to the central body (30), and including at least one processing device (51) configured to contact the wear-resistant layer, and - A first motor (52) for driving the processing device (51) to rotate. The central body (30) is characterized in that it includes or carries a template cam (70), the template cam including a cam profile (72) which depends on the desired surface profile of the processed wear-resistant layer (10b), and the processing tool (50) is movable relative to the template cam (70) and configured to follow the cam profile (72), such that the processing device (51) processes the wear-resistant layer (10b) according to the cam profile (72). Furthermore, the template cam (70) includes a flat plate (80) in which an elongated through slot (82) is formed, the slot (82) including a longitudinal edge (84) defining the desired surface profile, and the machining tool (51) includes a follower (91) that engages in the slot (82) and cooperates with the longitudinal edge (84) by sliding or rolling.

2. The tool (20) according to claim 1, wherein, The machining device is a ball end mill (51).

3. The tool (20) according to claim 1 or 2, wherein, The tool includes a second motor (32) for driving the machining tool (50) to rotate about the axis of rotation (A).

4. The tool (20) according to any one of the preceding claims, wherein, The motor, or each motor (32, 52), is a brushless electric motor.

5. The tool (20) according to any one of the preceding claims, wherein, The template cam (70) is removably and interchangeably mounted on the central body (30).

6. The tool (20) according to any one of the preceding claims, wherein, The plate (80) has a generally parallelepiped shape.

7. The tool (20) according to any one of the preceding claims, wherein, The plate (80) extends in a plane passing through the axis of rotation.

8. The tool (20) according to any one of the preceding claims, wherein, The driven member (91) is a roller.

9. The tool (20) according to any one of claims 5 to 8, wherein, The template cam (70) is clamped to the central body (30) by a mounting bracket (74) and / or a clamping screw (76).

10. The tool (20) according to any one of the preceding claims, wherein, The processing device (51) is housed in a cover (53) for protecting and containing chips and dust, the cover (53) being carried by the processing tool (50).

11. The tool (20) according to claim 10, wherein, The cover (53) is connected to a suction pump for chips and dust via a hose (54).

12. The tool (20) according to any one of the preceding claims, wherein, The tool also includes a measuring tool (40) connected to the central body (30) and including at least one probe (41) configured to be supported on the layer (10b), the measuring tool (40) being diametrically opposite the machining tool, for example, relative to the axis of rotation (A).

13. The tool (20) according to any one of the preceding claims, wherein, The central body (30) is equipped with a position-adjustable counterweight (94) to limit the force required to drive the central body to rotate about the axis of rotation (A).

14. The tool (20) according to any one of the preceding claims, wherein, The tool also includes template extensions (62, 64) configured to be mounted on both sides of the wear-resistant layer (10b) and axially clamped onto the wear-resistant layer (10b).

15. A method for machining an annular wear-resistant layer (10b) of the housing (3) of a fan (1) of an aircraft turbine engine using a tool (20) according to any one of the preceding claims, the method comprising the steps of: a) Determine the desired surface profile of the processed wear-resistant layer (10b), b) Select the template cam (70) and removably mount the template cam on the central body (30), the template cam including a cam profile (72) corresponding to the surface profile, and c) The wear-resistant layer (10b) is processed according to the cam profile (72).

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