WO2024227989A1 - Inspection device and method for inspecting at least one inner face of a drum for a turbine engine turbine or compressor - Google Patents

Abstract

The invention relates to an inspection device suitable for inspecting at least one inner face (71a, 72a, 71b) of an inter-disc cavity (74) of a longitudinal-axis (X) drum (70) for a turbine engine turbine or compressor, wherein the inspection device comprises an arm (30) that comprises a first segment (31) that extends between a first end and a second end along a first axis (A1) and a second segment (32) that extends between a first end and a second end along a second axis (A2), the second segment (32) being rigidly attached to the first segment (31), the second axis (A2) being inclined with respect to the first axis (A1); wherein an inspection head (33) comprises a base (34) that is pivotably mounted at the second end of the second segment (32) so as to pivot about a third axis (A3) perpendicular to the second axis (A2) and a high-resolution camera (35) rigidly attached to the base (34) having an optical axis (AO) that is perpendicular to the third axis (A3).

Description

Description

Title: Inspection device and inspection method for at least one internal face of a drum for a turbomachine compressor or turbine

Technical field

[0001] The present description relates to an inspection device for inspecting at least one internal face of a drum with a longitudinal axis for a compressor or turbine of a turbomachine. The present description also relates to a first assembly comprising such an inspection device and an actuator, as well as to an installation comprising such a first assembly. The present description also relates to a second assembly comprising such an inspection device and a locking mechanism of a transmission system of the device. Finally, the present description relates to a method for inspecting at least one internal face of a drum for a compressor or turbine of a turbomachine by means of the first assembly or in an installation comprising the first assembly.

Previous technique

[0002] A compressor or turbine drum for a turbomachine with a longitudinal axis comprises several rotor disks arranged one after the other along the axis of the turbomachine. The disks are connected to each other by annular walls which may be substantially cylindrical or frustoconical. The drum therefore has a tubular shape. Each disk and each annular wall defines at least one internal face of the drum. The drum further comprises annular interdisc cavities formed longitudinally between two longitudinally consecutive disks.

[0003] Such a drum is a critical part of the turbomachine so that after being machined and during regular inspection visits, the internal faces of the drum are inspected to ensure its conformity and that it does not have any defects (cracks, impacts, scratches, etc.) which could harm its integrity during operation of the turbomachine.

[0004] However, due to its geometry, inspection of the internal faces of the drum is difficult. The interdisc cavities are difficult to access. A known method for inspecting the internal faces at each interdisc cavity is endoscopy. However, this method does not allow images to be obtained with sufficient resolution to ensure a quality inspection. Furthermore, this method does not fully resolve the drawbacks related to the lack of access into the interdisc cavities and therefore does not allow inspection of all the internal faces of the interdisc cavities.

[0005] The present description aims in particular to provide a simple, economical and effective solution to the problems mentioned above. Summary

[0006] An inspection device is proposed that is suitable for inspecting at least one internal face of an interdisc cavity of a drum with a longitudinal axis for a turbomachine compressor or turbine, the inspection device comprising: an arm comprising a first segment extending between a first end and a second end along a first axis, and a second segment extending between a first end and a second end along a second axis, the second segment being integral with the first segment, the second axis being inclined relative to the first axis; an inspection head comprising: o a base pivotally mounted at the second end of the second segment about a third axis perpendicular to the second axis; o a high-resolution camera integral with the base and having an optical axis perpendicular to the third axis.

[0007] The device is adapted to insert the inspection head inside the drum, and in particular, in an annular interdisc cavity formed longitudinally between two longitudinally consecutive discs of the drum. Also, the pivoting of the inspection base makes it possible to inspect each internal face of the drum. In a particularly advantageous manner, thanks to the pivoting of the camera, each point of the internal faces of the drum can be inspected by ensuring that the optical axis does not form an angle greater than 45° with an axis passing through said point and oriented perpendicular to the internal face at said point. In other words, it is ensured that each point of each internal face of the drum can be inspected by having the optical axis of the camera included in a cone having said point as its apex and as its generator the axis passing through said point and oriented perpendicular to the internal face at said point. Thus, the quality of the images obtained by the camera is better and the inspection is improved.

[0008] The second axis may be perpendicular to the first axis. The third axis may be perpendicular to the first axis and the second axis.

[0009] A portion of the first end of the second segment may be integral with a portion of the second end of the first segment. The first segment and the second segment may be, in whole or in part, made of one piece (i.e. in one piece). Alternatively, the first segment and the second segment may be attached and fixed to each other.

[0010] The inspection device may comprise a transmission system adapted to be coupled with an actuator in order to pivot the base of the inspection head about the third axis. The first segment and the second segment may define an interior volume, for example parallelepiped, in which the transmission system is housed, in whole or in part. [0011] The inspection device is thus more compact, which facilitates its insertion into the drum, and in particular, into an annular interdisc cavity formed longitudinally between two longitudinally consecutive discs of the drum.

[0012] The transmission system may comprise at least: a first pinion arranged inside the first segment at the first end, the first pinion being adapted to be driven in rotation about a fourth axis by an actuator, a first belt arranged inside the first segment and meshing with the first pinion so as to be driven in rotation by the rotation of the first pinion about the fourth axis, a second pinion arranged inside the second segment at the second end, the second pinion being integral in rotation about the third axis with the base of the inspection head; a second belt arranged inside, on the one hand, the first segment, and on the other hand, the second segment, the second belt meshing with the second pinion so as to drive the second pinion in rotation about the third axis; a transmission mechanism for transmitting the rotational movement of the first belt to the second belt, the transmission mechanism being arranged inside the first segment at the second end.

[0013] The fourth axis may be perpendicular to the first axis and/or the second axis.

[0014] The transmission mechanism can mesh with the first belt and with the second belt. The transmission mechanism can comprise a third pinion pivotally mounted about a fifth axis relative to the first segment and meshing with the first belt. The transmission mechanism can comprise a fourth pinion pivotally mounted about the fifth axis relative to the first segment and meshing with the second belt. The third pinion and the fourth pinion can be integral in rotation with each other about the fifth axis, for example by means of a shaft extending along the fifth axis and on which each of the third pinion and the fourth pinion are fixedly mounted. Said shaft can be fixed to the first segment. The fifth axis can be parallel to the third axis.

[0015] The first belt and/or the second belt may each be toothed. The first belt may be driven in rotation about the first pinion and the third pinion. The second belt may be driven in rotation about the second pinion and the fourth pinion. It is not excluded that the transmission system may comprise at least one other pinion for guiding the rotation of the first belt and/or at least one other pinion for guiding the rotation of the second belt.

[0016] The inspection head may comprise lighting means adapted to emit light radiation in a direction coinciding with the optical axis. The inspection means can improve the quality of the image recorded by the camera and therefore make the inspection of the surface condition more precise. The inspection head can comprise a first lamp secured to the base and adapted to emit radiation in the ultraviolet in a direction coinciding with a direction of the optical axis of the camera and/or a second lamp secured to the base and adapted to emit white light in a direction coinciding with a direction of the optical axis.

[0017] The first lamp may be adapted to emit light radiation having a wavelength of between 250 nm and 400 nm, preferably between 350 nm and 375 nm, preferably equal to 365 nm. Such ultraviolet light radiation is particularly suitable for interacting with certain substances or products which reflect this radiation in the visible range.

[0018] The inspection head may comprise a lens arranged in front of the first lamp and adapted to filter light radiation with a wavelength between 250 nm and 400 nm. In other words, the lens may form a bandpass filter allowing light radiation having a wavelength between 250 nm and 400 nm to pass. The lens may form a bandpass filter having a central wavelength between 300 nm and 400 nm, preferably between 325 nm and 350 nm. The lens may have a transmittance greater than or equal to 40%. Thus, the first lamp and the lens may be arranged at a distance between 1 cm and 5 cm, preferably between 2 cm and 3 cm, from the illuminated surface while avoiding white light pollution. Indeed, known ultraviolet light sources are generally designed to be arranged at a distance of between 20 cm and 30 cm and their use at a reduced distance (for example between 1 cm and 5 cm) induces a white light on the illuminated surface which hinders the inspection of the surface under ultraviolet lighting. Also, the first lamp and the lens can be adapted to obtain a light power sufficient for the acquisition of images by the camera, in particular a light power greater than or equal to 1200 pW/cm ² , preferably between 4000 pW/cm ² and 5000 pW/cm ² .

[0019] The first lamp and/or the second lamp may be a LED (Light Emitting Diodes) lamp. The camera may have a resolution of between 2 Mpx and 16 Mpx. The camera may comprise a liquid lens. The inspection head may comprise a daughter electronic card. The inspection device may comprise a mother electronic card fixed to the first segment of the arm and connected to the daughter electronic card. The mother electronic card may be located closer to the second end of the first segment than to the first end of the first segment so as to reduce the length of the connections with the daughter electronic card.

[0020] The inspection head may comprise a brush secured to the base. The brush may be adapted to apply a product to the face to be inspected or to remove excess product from the face to be inspected. The pivoting control of the base allows the brush to be manipulated in an interdisc cavity, which may in particular be inaccessible to a human operator.

[0021] According to another aspect, there is provided a first assembly comprising the inspection device as described above and a motor which comprises a frame removably connected to the first segment of the arm and an output shaft coupled to the transmission system to pivot the inspection head around the third axis.

[0022] The inspection device can thus be interchanged with another inspection device having a geometry and/or dimensions adapted to the drum to be inspected while retaining the same actuator.

[0023] The first segment and/or the second segment of the arm may have dimensions adapted to the drum to be inspected. The inclination between the first axis and the second axis may be adapted to the drum to be inspected. The first segment may have a dimension along the first axis of between 300 mm and 1500 mm, preferably of between 400 mm and 1000 mm. In other words, the internal volume of the first segment may have a dimension along the first axis of between 300 mm and 1500 mm, preferably of between 400 mm and 1000 mm. The second segment may have a dimension along the second axis of between 80 mm and 400 mm, preferably of between 90 mm and 300 mm. In other words, the internal volume of the second segment may have a dimension along the second axis of between 80 mm and 400 mm, preferably of between 90 mm and 300 mm. Similarly, the head may have dimensions suitable for insertion into an interdisc cavity of the drum to be inspected.

[0024] The output shaft may extend along the fourth axis. The motor may be adapted to pivot the output shaft about the fourth axis. The output shaft may be arranged at least partly within the first segment at the first end. The first pinion may be mounted on the output shaft integral in rotation about the fourth axis and in a removable manner.

[0025] The angular correspondence between the output shaft of the motor and the first pinion when they are coupled can be obtained by the angular position known by the angular indexing of the first pinion and by a known reference angular position of the motor shaft.

[0026] According to another aspect, there is provided a second assembly comprising the inspection device as described above and a locking mechanism for immobilizing the first pinion inside the first segment, the locking mechanism preferably being adapted to angularly index the first pinion around the fourth axis relative to the first segment.

[0027] Such a locking mechanism firstly makes it possible to maintain the first pinion in position in the first segment, in particular when the latter is not coupled to an actuator. It also makes it possible to block a rotation of the first pinion around the fourth axis relative to the first segment and therefore a rotation of the first belt relative to the first segment, in particular when the transmission system is not connected to an actuator. In addition, the first pinion can be blocked in rotation by being angularly indexed, i.e. by knowing its angular position around the fourth axis, and therefore by knowing the angular position of the base of the inspection head around the third axis. Thus, the angular indexing of the first pinion makes it possible to couple the first pinion to an actuator in a known angular position, and therefore with an angular position of the base of the inspection head known around the third axis. This makes it possible to ensure correct calibration between the control of an actuator and the pivoting setpoint of the base of the inspection head around the third axis.

[0028] The inspection device may comprise a holding member arranged inside the first segment, secured to the first pinion. The holding member may comprise a recess in which the first pinion is partly housed. The holding member may be fixed to the first pinion, for example by screws. The holding member may be a disk centered on the fourth axis.

[0029] The locking mechanism may comprise at least one pin received jointly in a hole formed in the holding member and a hole formed in the arm. The pin may extend in the direction of the fourth axis. Thus, the holding member is made integral with the first segment. Such a pin makes it possible to simplify and shorten the uncoupling between the actuator and the first pinion with a view to changing the inspection device while retaining the same actuator.

[0030] The locking mechanism may comprise at least one screw securing the holding member to the first segment.

[0031] The locking mechanism may comprise a plate, bearing on an external face of the first segment at the first end in the direction of the first axis. Said pin may be integral with the plate. Said pin may also be received in an opening formed in the plate. Said screw of the locking mechanism may fix together said plate, the first segment and the holding member.

[0032] The holding member may bear on a first face of the first pinion in the direction of the fourth axis. The output shaft of the motor may comprise a shoulder on which bears, in the direction of the fourth axis, a second face of the first pinion, opposite the first face in the direction of the fourth axis. The first pinion may therefore be clamped between the shoulder of the output shaft and the holding member in the direction of the fourth axis. The holding member may be fixed to the output shaft, in particular by screwing in the direction of the fourth axis so as to obtain the clamping of the first pinion between the shoulder of the output member and the disk.

[0033] According to another aspect, there is provided an installation comprising the first assembly as described above and a polyarticulated robot which comprises joints defining at least six axes of rotation and which is adapted to move and/or orient a terminal member according to six degrees of freedom, a portion of the first end of the first segment of the arm of the inspection device being removably fixed to the terminal member of the polyarticulated robot.

[0034] The installation may further comprise a rotating support adapted to receive a drum with a longitudinal axis for a compressor or turbine of a turbomachine and to drive it in rotation around the longitudinal axis.

[0035] According to another aspect, there is provided a method of inspecting at least one internal face of a longitudinal axis drum for a turbomachine compressor or turbine by means of first assembly as described above, the drum comprising several annular discs arranged one after the other from upstream to downstream along the longitudinal axis and connected to each other by annular walls so that the drum comprises an internal cavity, the internal cavity further comprising annular inter-disc cavities formed longitudinally between each pair consisting of an upstream disc and a downstream disc longitudinally consecutive among the plurality of discs, each inter-disc cavity being delimited by a downstream face of the upstream disc, an upstream face of the downstream disc and an internal face of the annular wall connecting the upstream disc and the downstream disc, the method comprising the steps:

- moving the inspection device relative to the drum to partially insert the arm into the internal cavity of the drum until the inspection head is inside one of the interdisc cavities of the internal cavity of the drum;

- position the arm to arrange the third axis around which the base of the inspection head pivots perpendicular to the longitudinal axis;

- pivoting the base of the inspection head about the third axis and acquiring a plurality of successive images of at least one of the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall which delimit said interdisc cavity in which the inspection head is inserted, by means of the camera, during the pivoting of the base of the inspection head about the third axis.

[0036] The interdisc cavity in which the inspection head is inserted may have a minimum dimension in the longitudinal direction less than or equal to 30 mm. In other words, the minimum distance in the longitudinal direction separating the annular discs longitudinally delimiting the interdisc cavity on either side may be less than or equal to 30 mm. The minimum distance in the longitudinal direction separating the annular discs longitudinally delimiting the interdisc cavity on either side may be at a radially internal portion of the discs. Each interdisc cavity of the drum may have a minimum dimension in the longitudinal direction less than or equal to 30 mm.

[0037] The movement and positioning of the arm can be carried out by means of a polyarticulated robot. To insert the inspection head into one of the interdisc cavities, the inspection device can first be moved longitudinally to insert the inspection head, the second segment and a part of the first arm into a central part of the internal cavity, then moved radially to insert the inspection head into the interdisc cavity. The motor can be moved with the inspection device.

[0038] The drum may have a reference marking element, visible to the camera, to enable calibration of the position of the arm, and in particular of the inspection head, relative to the drum.

[0039] Once positioned, the first axis along which the first segment of the arm extends may be aligned with the longitudinal axis of the drum. The first segment may be partially received in the internal cavity of the drum. The second segment of the arm may be received in the internal cavity, and at least partially in the inspected interdisc cavity. The motor may be arranged outside the drum. [0040] The inclination of the first axis along which the first segment of the arm extends and the second axis along which the second segment of the arm extends may be determined according to, or even coincide with, the inclination of each disk relative to the longitudinal axis of the drum. Each disk may extend perpendicular to the longitudinal axis. In this case, the first axis and the second axis may be perpendicular to each other.

[0041] The pivoting of the inspection head base can be achieved at an angle between 0° and 360° by means of the motor.

[0042] The acquisition of the plurality of images can be done at a frequency between 1 fps and 60 fps.

[0043] The method may comprise, during the acquisition of the plurality of images, the illumination of said at least one of the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall which delimit said interdisc cavity, by means of the first lamp or the second lamp.

[0044] The acquisition of the plurality of images with illumination by means of the first lamp (with ultraviolet radiation) can be carried out after having applied an indicator product making it possible to materialize surface defects on the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall which delimit said inspected interdisc cavity. This can be, for example, a fluorescent penetrating product capable of being sprayed. This makes it possible to highlight emerging discontinuities (fissure, crack, etc.) on the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall which delimit said interdisc cavity during the acquisition of the plurality of images. The illumination by means of the first lamp (with ultraviolet radiation) can be carried out through (or by means of) a band-pass lens allowing light radiation to pass through having a wavelength of between 250 nm and 400 nm and having a transmittance greater than or equal to 40%. Said at least one of the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall which delimit said interdisc cavity can be illuminated by means of the first lamp with the latter arranged at a distance of between 1 cm and 5 cm, preferably of between 2 cm and 3 cm.

[0045] The acquisition of the plurality of images with illumination by means of the second lamp (white light) makes it possible to check the possible presence of impacts or scratches on the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall which delimit said inspected interdisc cavity.

[0046] The method may comprise, after acquiring the plurality of images, a step comprising rotating the drum about the longitudinal axis by means of the rotating support and repeating the steps of pivoting the base of the inspection head about the third axis and acquiring a plurality of successive images of at least one of the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall which delimit said interdisc cavity in which the inspection head is inserted, by means of the camera, during the pivoting of the base of the inspection head about the third axis. [0047] The angular extent covered by the camera around the longitudinal axis on the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall which delimit said interdisc cavity in which the inspection head is inserted during the acquisition of the plurality of images may comprise each point of the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall for which an angle between the optical axis of the camera and an axis passing through said point while being perpendicular respectively to the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall is less than 45°.

[0048] An angle of rotation of the drum around the longitudinal axis by means of the rotating support can be determined as a function of, or even equal to, the angular extent covered by the camera around the longitudinal axis on the downstream face of the upstream disk, the upstream face of the downstream disk and the internal face of the annular wall which delimit said interdisc cavity in which the inspection head is inserted.

[0049] The steps of rotating the drum about the longitudinal axis and repeating the steps of pivoting the base of the inspection head about the third axis and acquiring a plurality of successive images can be repeated until a rotation of the drum about the longitudinal axis of 360° is obtained.

[0050] The steps of the method as described above can be repeated for each interdisc cavity of the drum.

Brief description of the drawings

[0051] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the attached drawings, in which:

[0052] Figure 1 is a perspective view showing an installation for inspecting at least one internal face of a compressor drum or turbine for a turbomachine;

[0053] Figure 2 is a first perspective view showing an inspection device and a motor of the installation of Figure 1;

[0054] Figure 3 is an enlarged view of the boxed area of the inspection device of Figure 1;

[0055] Figure 4 is a second perspective view of the inspection device and motor of Figure 2;

[0056] Figure 5 is a partial perspective view of the inspection device and motor of Figure 2 and shows in more detail a locking mechanism;

[0057] Figure 6 is a partial sectional view of the inspection device and motor of Figure 2 which also shows in more detail the locking mechanism;

[0058] Figure 7 is a functional diagram of a method of inspecting at least one internal face of a compressor or turbine drum for a turbomachine;

[0059] Figure 8 represents a step of the method of Figure 7. Description of the embodiments

[0060] Reference is now made to FIG. 1 which represents an installation 10 for the inspection of at least one internal face of a drum 70 of longitudinal axis X of a compressor or turbine for a turbomachine.

[0061] In the present disclosure, the longitudinal direction corresponds to the direction of the longitudinal axis X. The longitudinal axis X coincides with the main extension direction of the drum 70 and with the direction of flow of the gases from upstream to downstream in the drum 70 when the latter is in a turbomachine in operation. The orientation qualifiers, such as “longitudinal”, “radial” or “circumferential” are defined unless otherwise specified by reference to the longitudinal axis X. A radial direction is a direction perpendicular to the direction of the longitudinal axis X. A circumferential direction, at a point remote from the longitudinal axis X, corresponds to a direction perpendicular to the longitudinal and radial directions. Furthermore, unless otherwise specified, the adjectives "inner", "inner", "outer" and "outer" are used in reference to a radial direction such that the inner/inner portion (i.e. radially inner/inner) of an element is closer to the longitudinal axis X than the outer/outer portion (i.e. radially outer/outer) of the same element. Finally, the relative qualifiers "upstream" and "downstream" are defined with respect to the normal flow direction of the fluid (from upstream to downstream) in the drum 70.

[0062] The drum 70 comprises several annular disks 71 arranged one after the other from upstream to downstream along the longitudinal axis X and connected to each other by annular walls 72. In other words, two longitudinally consecutive disks 71 are connected to each other by an annular wall 72. Each disk 71 may in particular comprise an annular hub, also sometimes called a balancing “leek” because of its geometry. A radially external periphery of the hub of each disk 71 may be adapted to receive an annular row of compressor or turbine blades. In the example illustrated and described below, each disk 71 extends perpendicular to the longitudinal axis X. However, variant embodiments in which the disks 71 are inclined relative to the longitudinal axis X are not excluded. Each annular wall 72 connects radially external end portions of the disks 71, in particular hubs of the disks 71. The annular walls 72 may be cylindrical or frustoconical about the longitudinal axis X. The drum 70 may have an axisymmetric shape about the longitudinal axis X. The drum 70 therefore comprises an internal cavity 73. In other words, the drum 70 has a tubular shape about the longitudinal axis X. The internal cavity 73 comprises annular interdisc cavities 74 formed longitudinally between each pair consisting of an upstream disk 71 and a downstream disk 71 longitudinally consecutive among the plurality of disks 71. Each interdisc cavity 71 being delimited by a downstream face 71a of the upstream disc 71, an upstream face 71b of the downstream disc 71 and an internal face of the annular wall 72 connecting the upstream disc 71 and the downstream disc 71. The internal cavity 73 also comprises a central part arranged radially inside the discs 71 and the interdisc cavities 74.

[0063] The installation 10 visible in FIG. 1 comprises a polyarticulated robot 11, an inspection device and an actuator. The polyarticulated robot 11 is a so-called “six-axis” robot in that it comprises joints defining at least six axes of rotation and in that it is adapted to move and/or orient a terminal organ according to six degrees of freedom.

[0064] The installation 10 also comprises a rotating support 12 adapted to receive a drum 70 of longitudinal axis X for a compressor or turbine of a turbomachine and to drive it in rotation about the longitudinal axis X. Also visible in FIG. 1, a drum 70 of a turbomachine as described above and arranged on the rotating support 12.

[0065] The inspection device is visible in more detail in FIGS. 2 to 6. The device comprises an arm 30 comprising a first segment 31 and a second segment 32. The first segment 31 extends between a first end and a second end along a first axis A1, and the second segment 32 extends between a first end and a second end along a second axis A2. The second axis A2 is inclined relative to the first axis A1. The second axis A2 is here perpendicular relative to the first axis A1. The second segment 32 is integral with the first segment 31. In this case, a portion of the first end of the second segment 32 is here integral with a portion of the second end of the first segment 31. As visible in FIG. 3, the first segment 31 and the second segment 32 are here made in one piece (i.e. in one piece). Alternatively, the first segment 31 and the second segment 32 may be attached and fixed to each other. A portion of the first end of the first segment 31 of the arm 30 of the inspection device is adapted to be removably fixed to the end member of the polyarticulated robot 11, for example by screwing. Finally, the first segment 31 and the second segment 32 define an interior volume.

[0066] The inspection device further comprises an inspection head 33. The inspection head 33 firstly comprises a base 34 pivotally mounted at the second end of the second segment 32 about a third axis A3 perpendicular to the second axis A2. The third axis A3 is here perpendicular to the first axis A1 and to the second axis A2. The inspection head 33 also comprises a high-resolution camera 35 secured to the base 34 and having an optical axis AO perpendicular to the third axis A3. The camera 35 may have a resolution of between 2 Mpx and 16 Mpx. The camera 35 may comprise a liquid lens.

[0067] The device is therefore suitable for inserting the inspection head 33 inside the drum 70, and in particular, in one of the interdisc cavities 74. In a particularly advantageous manner, thanks to the pivoting of the camera 35, each point of the faces delimiting the interdisc cavities 74 of the drum 70 can be inspected by ensuring that the optical axis AO does not form an angle greater than 45° with an axis passing through said point and oriented perpendicular to the internal face at said point. In other words, it is ensured that each point of each internal face of the drum 70 can be inspected by having the optical axis of the camera 35 included in a cone having said point as its apex and as its generator the axis passing through said point and oriented perpendicular to the internal face at said point. Thus, the quality of the images obtained by the camera 35 is better and the inspection is improved.

[0068] The inspection head 33 also comprises a first lamp 36 and a second lamp 37 secured to the base 34. The first lamp 36 is adapted to emit radiation into ultraviolet in a direction coinciding with a direction of the optical axis AO of the camera 35. The second lamp 37 is adapted to emit white light in a direction coinciding with a direction of the optical axis AO. The first lamp 36 and/or the second lamp 37 may be a LED (Light Emitting Diodes) lamp 35. The inspection head 33 may comprise a daughter electronic card 52 allowing the control of the camera 35, the first lamp 36 and the second lamp 37 and the processing of the images acquired by the camera.

[0069] The device further comprises a transmission system adapted to be coupled with the actuator in order to pivot the base 34 of the inspection head 33 about the third axis A3. The actuator is here a motor 20 which comprises a frame 21 removably connected to the first segment 31 of the arm 30 and an output shaft 22 coupled to the transmission system to pivot the inspection head 33 about the third axis A3. The inspection device can thus be interchanged with another inspection device having a geometry and/or dimensions adapted to the drum 70 to be inspected while retaining the same actuator. The output shaft 22 extends along a fourth axis A4. The fourth axis A4 is here perpendicular to the first axis A1 and to the second axis A2. The motor 20 is able to pivot the output shaft 22 about the fourth axis A4. The output shaft 22 is arranged at least partly inside the first segment 31 at the first end. In this case, a distal end portion of the output shaft 22 is arranged inside the first segment 31.

[0070] The transmission system is housed, in whole or in part, the transmission system. The inspection device is thus more compact, which facilitates its insertion into the drum 70, and in particular, into an annular interdisc cavity 74 formed longitudinally between two longitudinally consecutive discs 71 of the drum 70.

[0071] The transmission system comprises a first pinion 41 and a second pinion 42. The first pinion 41 is arranged inside the first segment 31 at the first end. The first pinion 41 is adapted to be driven in rotation about a fourth axis A4 by an actuator. For this purpose, the first pinion 41 is mounted on the output shaft 22 integral in rotation about the fourth axis A4 and in a removable manner. The second pinion 42 is arranged inside the second segment 32 at the second end. The second pinion 42 is integral in rotation about the third axis A3 with the base 34 of the inspection head 33.

[0072] The system comprises a first belt 45 and a second belt 46. The first belt 45 is arranged inside the first segment 31 and meshing with the first pinion 41 so as to be driven in rotation by the rotation of the first pinion 41 about the fourth axis A4. The second belt 46 is arranged inside, on the one hand, the first segment 31, and on the other hand, the second segment 32, the second belt 46 meshing with the second pinion 42 so as to drive the second pinion 42 in rotation about the third axis A3.

[0073] The transmission system also comprises a transmission mechanism for transmitting the rotational movement of the first belt 45 to the second belt 46. The transmission mechanism is arranged inside the first segment 31 at the second end. The transmission mechanism meshes with the first belt 45 and with the second belt 46. The transmission mechanism comprises a third pinion 43 pivotally mounted about a fifth axis A5 relative to the first segment 31 and which meshes with the first belt 45, and a fourth pinion 44 pivotally mounted about the fifth axis A5 relative to the first segment 31 and which meshes with the second belt 46. The fifth axis A5 may be parallel to the third axis A3. The third pinion 43 and the fourth third are integral in rotation with each other about the fifth axis A5, by means of a shaft 47 extending along the fifth axis A5 and on which they are fixedly mounted. Said shaft 47 may be fixed to the first segment 31.

[0074] The first belt 45 is therefore driven in rotation around the first pinion 41 and the third pinion 43. The second belt 46 is driven in rotation around the second pinion 42 and the fourth pinion 44. The first belt 45 and/or the second belt 46 may each be toothed. It is not excluded that the transmission system may comprise at least one other pinion and/or roller for guiding in rotation or maintaining tension of the first belt 45 and/or at least one other pinion and/or roller for guiding in rotation or maintaining tension of the second belt 46.

[0075] The inspection device further comprises a holding member 48 arranged inside the first segment 31, secured to the first pinion 41. The holding member 48 comprises a recess in which the first pinion 41 is partly housed. The holding member 48 is here fixed to the first pinion 41 by screws 49. The holding member 48 is here again a disk 71 centered on the fourth axis A4. The holding member 48 bears on a first face of the first pinion 41 in the direction of the fourth axis A4. The output shaft 22 of the motor 20 further comprises a shoulder on which a second face of the first pinion 41 bears, in the direction of the fourth axis A4, opposite the first face in the direction of the fourth axis A4. The first pinion 41 is therefore clamped between the shoulder of the output shaft 22 and the holding member 48 in the direction of the fourth axis A4. The holding member 48 is fixed to the output shaft 22, here by a screw 23 extending in the direction of the fourth axis A4 so as to obtain the clamping of the first pinion 41 between the shoulder of the output member and the disk.

[0076] In the event that the inspection device must be uncoupled from the motor 20, a locking mechanism is provided to immobilize the first pinion 41 inside the first segment 31. The locking mechanism is also adapted to angularly index the first pinion 41 around the fourth axis A4 relative to the first segment 31.

[0077] Such a locking mechanism firstly makes it possible to maintain the first pinion 41 in position in the first segment 31, in particular when the latter is not coupled to an actuator. It also makes it possible to block a rotation of the first pinion 41 around the fourth axis A4 relative to the first segment 31 and therefore a rotation of the first belt 45 relative to the first segment 31, in particular when the transmission system is not connected to an actuator. In addition, the first pinion 41 can be blocked in rotation by being angularly indexed, that is to say by knowing its angular position around the fourth axis A4, and therefore by knowing the angular position of the base 34 of the inspection head 33 around the third axis A3. Thus, the angular indexing of the first pinion 41 makes it possible to couple the first pinion 41 to a actuator in a known angular position, and therefore with an angular position of the base 34 of the inspection head 33 known around the third axis A3. This makes it possible to ensure correct calibration between the control of an actuator and the setpoint in pivoting the base 34 of the inspection head 33 around the third axis A3.

[0078] The angular correspondence between the output shaft 22 of the motor 20 and the first pinion 41 during their coupling can be obtained by the angular position known by the angular indexing of the first pinion 41 and by a known reference angular position of the motor shaft 20.

[0079] The locking mechanism here comprises two pins 62 each received respectively both in a hole formed in the holding member 48 and a hole formed in the arm 30. Each pin 62 extends in the direction of the fourth axis A4. Thus, the holding member 48 is made integral with the first segment 31. Such a pin 62 makes it possible to simplify and shorten the uncoupling between the actuator and the first pinion 41 with a view to changing the inspection device while retaining the same actuator. When the inspection device is stored (i.e. when it is not in use), the locking mechanism may comprise at least two screws 63 fixing the holding member 48 to the first segment 31. The locking mechanism here also comprises a plate 61, bearing on an external face of the first segment 31 at the first end in the direction of the fourth axis A4. Each pin 62 is secured to the plate 61 (for visibility purposes, the pins 62 are shown in FIG. 5 on the opposite side of the plate 61 relative to the arm 30). As seen in FIG. 6, the pins 62 are further received in an opening formed in the plate 61. Similarly, each screw 63 of the locking mechanism secures together said plate 61, the first segment 31 and the holding member 48.

[0080] Finally, the inspection device comprises a mother electronic card 51 fixed to the first segment 31 of the arm 30 and connected to the daughter electronic card 52. The mother electronic card 51 is located closer to the second end of the first segment 31 than to the first end of the first segment 31 so as to reduce the length of the connections with the daughter electronic card 52.

[0081] With reference to FIGS. 7 and 8, a method 100 is now described for inspecting at least one internal face of a drum 70 of longitudinal axis X for a compressor or turbine of a turbomachine as described above, in particular at least one face delimiting one of the interdisc cavities 74 of the drum 70, and by means of the installation 10 as described above.

[0082] The method 100 comprises a first step 110. The first step 110 comprises moving the inspection device relative to the drum 70 to partially insert the arm 30 into the internal cavity 73 of the drum 70 until the inspection head 33 is inside one of the interdisc cavities 74 of the internal cavity 73 of the drum 70. The movement and positioning of the arm 30 are carried out by means of a polyarticulated robot 11. To insert the inspection head 33 into one of the interdisc cavities 74, the inspection device is first moved longitudinally to insert the inspection head 33, the second segment 32 and a portion of the first arm 30 into the central portion of the internal cavity 73, then moved radially to insert the inspection head 33 in the interdisc cavity 74. The motor 20 is moved with the inspection device. The drum 70 may have a reference marking element radially inside, visible by the camera 35, to allow the calibration of the position of the arm 30, and in particular of the inspection head 33, relative to the drum 70.

[0083] The method 100 comprises a second step 120. The second step 120 comprises the positioning of the arm 30 to arrange the third axis A3 around which the base 34 of the inspection head 33 pivots perpendicular to the longitudinal axis X. Once positioned, the first axis A1 along which the first segment 31 of the arm 30 extends is aligned with the longitudinal axis X of the drum 70. The first segment 31 is partly received in the internal cavity 73 of the drum 70. The second segment 32 of the arm 30 is furthermore entirely arranged in the internal cavity 73, and partly in the inspected interdisc cavity 71. The motor 20 remains arranged outside the drum 70.

[0084] The method 100 comprises a third step 130. The third step 130 is shown in FIG. 8. The third step 130 comprises a first subsidiary step 110 which comprises the pivoting of the base 34 of the inspection head 33 around the third axis A3 (represented by the arrow R in FIG. 8). The pivoting of the base 34 of the inspection head 33 can be carried out at an angle between 0° and 360° by means of the motor 20.

[0085] The third step 130 comprises a second subsidiary step 120 carried out simultaneously with the first subsidiary step 110 of the third step 130. The second subsidiary step 120 comprises the acquisition of a plurality of successive images of at least one of the downstream face 71a of the upstream disk 71, the upstream face 71b of the downstream disk 71 and the internal face 72a of the annular wall 72 which delimit said interdisc cavity 74 in which the inspection head 33 is inserted, by means of the camera 35, during the pivoting of the base 34 of the inspection head 33 about the third axis A3. The acquisition of the plurality of images can be done at a frequency of between 1 fps and 60 fps.

[0086] The third step 130 comprises a third subsidiary step 130 carried out simultaneously with the first subsidiary step 110 and the second subsidiary step 120 of the third step 130. The third subsidiary step 130 comprises the lighting of said at least one of the downstream face 71a of the upstream disk 71, the upstream face 71b of the downstream disk 71 and the internal face 72a of the annular wall 72 which delimit said interdisc cavity 74, by means of the first lamp 36 or the second lamp 37.

[0087] The acquisition of the plurality of images with illumination by means of the first lamp 36 (ultraviolet radiation) can be carried out after having applied an indicator product making it possible to materialize surface defects on the downstream face 71a of the upstream disk 71, the upstream face 71b of the downstream disk 71 and the internal face 72a of the annular wall 72 which delimit said interdisc cavity 74 inspected. This can be, for example, a fluorescent penetrating product capable of being sprayed. This makes it possible to highlight emerging discontinuities (crack, split, etc.) on the downstream face 71a of the upstream disk 71, the upstream face 71b of the downstream disk 71 and the internal face 72a of the annular wall 72 which delimit said interdisc cavity 74 during the acquisition of the plurality of images. [0088] The acquisition of the plurality of images with illumination by means of the second lamp 37 (white light) makes it possible to check the possible presence of impacts or scratches on the downstream face 71a of the upstream disk 71, the upstream face 71b of the downstream disk 71 and the internal face 72a of the annular wall 72 which delimit said interdisc cavity 74 inspected.

[0089] The method 100 comprises a fourth step 140. The fourth step 140 is carried out simultaneously with or after the third step 130. The fourth step 140 comprises the rotation of the drum 70 around the longitudinal axis X by means of the rotating support 12.

[0090] The angular extent covered by the camera 35 around the longitudinal axis X on the downstream face 71a of the upstream disk 71, the upstream face 71b of the downstream disk 71 and the internal face 72a of the annular wall 72 which delimit said interdisc cavity 74 in which the inspection head 33 is inserted when the acquisition of the plurality of images is requested comprises each point of the downstream face 71a of the upstream disk 71, the upstream face 71b of the downstream disk 71 and the internal face 72a of the annular wall 72 for which an angle between the optical axis AO of the camera 35 and an axis passing through said point while being perpendicular respectively to the downstream face 71a of the upstream disk 71, the upstream face 71b of the downstream disk 71 and the internal face 72a of the annular wall 72 is less than 45°.

[0091] An angle of rotation of the drum 70 around the longitudinal axis X by means of the rotating support 12 can be determined as a function of, or even equal to, the angular extent covered by the camera 35 around the longitudinal axis X on the downstream face 71a of the upstream disk 71, the upstream face 71b of the downstream disk 71 and the internal face 72a of the annular wall 72 which delimit said interdisc cavity 74 in which the inspection head 33 is inserted.

[0092] The third step 130 and the fourth step 140 can be repeated until the drum 70 has rotated about the longitudinal axis X by 360°.

[0093] Finally, the steps of the method 100 as described above can be repeated for each interdisc cavity 74 of the drum 70.

Claims

Claims [Claim 1] Inspection device adapted to inspect at least one internal face (71 a, 72a, 71 b) of an interdisc cavity (74) of a drum (70) of longitudinal axis (X) for a turbomachine compressor or turbine, the inspection device comprising: an arm (30) comprising a first segment (31) extending between a first end and a second end along a first axis (A1), and a second segment (32) extending between a first end and a second end along a second axis (A2), the second segment (32) being integral with the first segment (31), the second axis (A2) being inclined relative to the first axis (A1); an inspection head (33) comprising: o a base (34) pivotally mounted at the second end of the second segment (32) about a third axis (A3) perpendicular to the second axis (A2); o a high-resolution camera (35) secured to the base (34) and having an optical axis (AO) perpendicular to the third axis (A3). [Claim 2] Inspection device according to the preceding claim, comprising a transmission system adapted to be coupled with an actuator in order to pivot the base (34) of the inspection head (33) around the third axis (A3), and in which the first segment (31) and the second segment (32) define an interior volume in which the transmission system is housed, in whole or in part. [Claim 3] Inspection device according to the preceding claim, wherein the transmission system comprises at least: a first pinion (41) arranged inside the first segment (31) at the first end, the first pinion (41) being adapted to be driven in rotation about a fourth axis (A4) by an actuator, a first belt (45) arranged inside the first segment (31) and meshing with the first pinion (41) so as to be driven in rotation by the rotation of the first pinion (41) about the fourth axis (A4), a second pinion (42) arranged inside the second segment (32) at the second end, the second pinion (42) being integral in rotation about the third axis (A3) with the base (34) of the inspection head (33); a second belt (46) arranged inside, on the one hand, the first segment (31), and on the other hand, the second segment (32), the second belt (46) meshing with the second pinion (42) so as to drive the second pinion (42) in rotation about the third axis (A3); a transmission mechanism (43; 44; 47) for transmitting the rotational movement of the first belt (45) to the second belt (46), the transmission mechanism (43; 44; 47) being arranged inside the first segment (31) at the second end. [Claim 4] Inspection device according to any one of the preceding claims, the inspection head (33) comprising a first lamp (36) secured to the base and adapted to emit radiation in the ultraviolet in a direction coinciding with a direction of the optical axis (AO) of the camera (35) and/or a second lamp (37) secured to the base and adapted to emit white light in a direction coinciding with a direction of the optical axis (AO). [Claim 5] Device according to the preceding claim, in which the inspection head (33) comprises a lens arranged in front of the first lamp (36) and adapted to filter light radiation with a wavelength between 250 nm and 400 nm, the lens having a transmittance greater than or equal to 40%. [Claim 6] Device according to any one of the preceding claims, the inspection head (33) comprises a brush secured to the base and adapted to apply a product to the face to be inspected or to remove excess product from the face to be inspected. [Claim 7] First assembly comprising the inspection device according to any one of the preceding claims and a motor which comprises a frame removably connected to the first segment of the arm and an output shaft coupled to the transmission system for pivoting the inspection head about the third axis. [Claim 8] Second assembly comprising the inspection device according to claim 3, and a locking mechanism for immobilizing the first pinion (41) inside the first segment (31), the locking mechanism preferably being adapted to angularly index the first pinion (41) around the fourth axis (A4) relative to the first segment (31). [Claim 9] Second assembly according to the preceding claim, in which the inspection device comprises a holding member (48) arranged inside the first segment (31), integral with the first pinion (41), and the locking mechanism comprises at least one pin (62) received jointly in a hole formed in the holding member (48) and a hole formed in the arm (30). [Claim 10] Installation (10) comprising the first assembly according to claim 5 and a polyarticulated robot (11) which comprises joints defining at least six axes of rotation and which is adapted to move and/or orient a terminal member according to six degrees of freedom, a portion of the first end of the first segment (31) of the arm (30) of the inspection device being removably fixed to the terminal member of the polyarticulated robot (11). [Claim 11] Installation (10) according to the preceding claim, further comprising a rotating support (12) adapted to receive a drum (70) of longitudinal axis (X) for a compressor or turbine of a turbomachine and to drive it in rotation around the longitudinal axis (X). [Claim 12] Method (100) for inspecting at least one internal face (71 a, 72a, 71 b) of an interdisc cavity (74) of a drum (70) of longitudinal axis (X) for a compressor or turbine of turbomachine by means of the first assembly according to claim 5, the drum comprising several annular discs (71) arranged one after the other from upstream to downstream along the longitudinal axis (X) and connected to each other by annular walls (72) so that the drum comprises an internal cavity (73), the internal cavity (73) further comprising annular interdisc cavities (74) formed longitudinally between each pair consisting of an upstream disc (71) and a downstream disc (71) longitudinally consecutive among the plurality of discs, each interdisc cavity (74) being delimited by a downstream face (71a) of the upstream disc (71), an upstream face (71b) of the downstream disc (71) and an internal face (72a) of the annular wall (72) connecting the upstream disc (71) and the downstream disc (71), the method comprising the steps of: moving the inspection device relative to the drum (70) to partially insert the arm (30) into the internal cavity (73) of the drum (70) until the inspection head (33) is inside one of the interdisc cavities (74) of the internal cavity (73) of the drum (70); position the arm (30) to arrange the third axis (A3) around which the base (34) of the inspection head (33) pivots perpendicular to the longitudinal axis (X); pivot the base (34) of the inspection head (33) around the third axis (A3) and acquire a plurality of successive images of at least one of the downstream face (71 a) of the upstream disk (71), the upstream face (71 b) of the downstream disc (71 ) and the internal face (72a) of the annular wall (72) which delimit said interdisc cavity (74) in which the inspection head (33) is inserted, by means of the camera (35), during the pivoting (R) of the base (34) of the inspection head (33) around the third axis (A3). [Claim 13] Method (100) according to the preceding claim, by means of the assembly according to claim 5 implemented in an installation according to claim 8, the method (100) comprising, after the acquisition of the plurality of images, a step comprising the rotation of the drum (70) about the longitudinal axis (X) by means of the rotating support (12) and the repetition of the steps of pivoting the base (34) of the inspection head (33) about the third axis (A3) and of acquiring a plurality of successive images of at least one of the downstream face (71 a) of the upstream disk (71 ), the upstream face (71 b) of the downstream disk (71 ) and the internal face (72a) of the annular wall (72) which delimit said interdisc cavity (74) in which the inspection head (33) is inserted, by means of the camera (35), during the pivoting (R) of the base (34) of the inspection head (33) around the third axis (A3). [Claim 14] Method (100) according to the preceding claim, wherein an angle of rotation of the drum (70) around the longitudinal axis (X) by means of the rotating support (12) is equal to an angular extent covered by the camera (35) around the longitudinal axis (X) on the downstream face (71 a) of the upstream disk (71 ), the upstream face (71 b) of the downstream disk (71 ) and the internal face (72a) of the annular wall (72) which delimit said interdisc cavity (74) in which the inspection head (33) is inserted. [Claim 15] A method (100) according to any one of claims 12 to 14, wherein the angular extent covered by the camera (35) around the longitudinal axis (X) on the downstream face (71 a) of the upstream disk (71), the upstream face (71 b) of the downstream disk (71) and the internal face (72a) of the annular wall (72) which delimit said interdisc cavity (74) in which the inspection head (33) is inserted during the acquisition of the plurality of images may comprise each point of the downstream face (71 a) of the upstream disk (71), the upstream face (71 b) of the downstream disk (71) and the internal face (72a) of the annular wall (72) for which an angle between the optical axis (AO) of the camera (35) and an axis passing through said point while being perpendicular respectively to the downstream face (71 a) of the disk upstream (71), the upstream face (71b) of the downstream disc (71) and the internal face (72a) of the annular wall (72) is less than 45°.