DE102017223711A1 - Method for measuring a fir-tree-shaped blade root, measuring device and system comprising such a - Google Patents

Abstract

The invention relates to a method for measuring a fir-tree-shaped blade root (2) of a turbine blade (3), in which a blade root (2) having a fir-tree-shaped profile and having a plurality of anchoring teeth (6) extending in a longitudinal direction forming the fir tree-shaped profile ), each defining a longitudinally extending facing support flank (8) and an opposite, also in the longitudinal direction extending free flank (9) is provided - the fir tree-shaped blade root (2) in a tool holder (14) of a provided measuring device ( 1) is used, - with several scanning devices (20) the support flanks (8) of several teeth (6) on one side of the fir-tree-shaped blade root (2) are scanned, the scanning means (20) along the blade root (2) moved in the longitudinal direction and thereby measured values are recorded with the scanning devices (20) Furthermore, the invention relates to a measuring device (1) for carrying out the method and a system comprising such a measuring device (1) and at least one turbine blade (3) with a fir-tree-shaped blade root (2) to be measured.

Description

The invention relates to a method for measuring a fir tree-shaped blade root of a particular already in operation before turbine blade. Furthermore, the invention relates to a measuring device for carrying out the method and a system comprising such a measuring device and at least one turbine blade with a fir-tree-shaped blade root to be measured.

In particular for fastening rotor blades to the shaft of a turbine, it is known to provide these with a fir-tree-shaped blade root, which can be inserted in the axial direction into a correspondingly shaped fastening groove, for example a wheel disc of the shaft. A fir-tree-shaped blade root, in a manner well known in the prior art, has a plurality of anchoring teeth forming the fir-tree-shaped profile, which extend in a longitudinal direction and form undercuts for the attachment. Each of the anchoring teeth defines a supporting flank facing in particular the blade tip, that is to say pointing radially outward, and an opposite free flank which also extends in the longitudinal direction and in particular points radially inward. A fir-tree-shaped blade root, for example, the 1 which is also attributable to the Applicant EP 2 322 764 A1 be removed. The fir tree profile is usually symmetrical with an equal number of anchoring teeth on two opposite sides of the foot.

In operation, the blades are exposed to high centrifugal forces due to the rapid rotation of the shaft. As a result, it can lead to deformations, including a distortion of the airfoil. An original reference system, such as a so-called six-point nest, is then sometimes no longer useful. Also due to decoctions or the like, a reference can be lost. A precise alignment of the component is then very difficult or is no longer possible. A determination of the operationally changed geometry, which may be of interest in particular for an estimation of the remaining service life, can then no longer or only with great effort. If no such information is available, it is not possible, for example, to determine whether the installation of a blade which has already been in operation is still possible prior to reassembly, and a high outlay can be caused by "tryand error".

The Applicant has found that, with blades having a fir-tree-shaped foot, after operation, a most useful reference is still to be found in the supporting flanks of the foot. In the case of some turbine blade feet, a distortion, in particular a crowning of the bearing flanks, can be qualitatively recognized. Added to this is the assumption of the applicant that a change in the Tragflankenabstandes has set. This can have a very sensitive effect on the blade foot life and the wheel disc. Operational geometry changes in the area of the foot are thus of great importance for the further usability of turbine blades.

It is therefore an object of the present invention to provide a measuring method and a measuring device which enables a reliable measurement of the fir tree-shaped foot, in particular of turbine blades already in operation, with comparatively little effort.

• - ein zu vermessender Schaufelfuß mit tannenbaumförmigem Profil, der eine Mehrzahl von sich in einer Längsrichtung erstreckenden, das tannenbaumförmige Profil bildenden Verankerungszähnen aufweist, die jeweils eine sich in Längsrichtung erstreckende insbesondere der Schaufelspitze zugewandte Tragflanke und eine gegenüberliegende, sich ebenfalls in Längsrichtung erstreckende Freiflanke definieren, bereitgestellt wird,
• - der tannenbaumförmige Schaufelfuß in eine Werkzeugaufnahme einer bereitgestellten Messvorrichtung eingesetzt wird,
• - mit mehreren, insbesondere zumindest einer der Anzahl der Verankerungszähne auf einer Seite des tannenbaumförmigen Schaufelfußes entsprechenden Anzahl von Abtasteinrichtungen die Tragflanken von mehreren, insbesondere allen Zähnen auf einer Seite des tannenbaumförmigen Schaufelfußes abgetastet werden, wobei die Abtasteinrichtungen bevorzugt gleichzeitig entlang des Schaufelfußes in Längsrichtung verfahren und dabei mit den Abtasteinrichtungen Messwerte erfasst werden.

This object is achieved by a method for measuring a fir-tree-shaped blade root of a turbine blade, in particular already in operation, in which

• a blade root to be measured having a fir-tree-shaped profile, which has a plurality of anchoring teeth which extend in a longitudinal direction and form the fir-tree-shaped profile, each defining a support flank extending in the longitudinal direction, in particular the blade tip, and an opposite free flank also extending in the longitudinal direction, provided,
• the fir tree-shaped blade root is inserted into a tool receptacle of a provided measuring device,
• - With several, in particular at least one of the number of anchoring teeth on one side of the fir tree-shaped blade root corresponding number of scanning the support flanks of several, in particular all teeth are scanned on one side of the fir-tree-shaped blade root, wherein the scanning preferably simultaneously moved along the blade root in the longitudinal direction and measured values are recorded with the scanning devices.

In other words, the basic idea of the present invention is to scan the support flanks of the anchoring teeth of a fir-tree-shaped blade root for a particularly reliable and at the same time easy to carry out geometry measurement, whereby several scanning devices are used which are defined in the longitudinal direction of the blade root, ie along the anchoring teeth and therefrom Supporting flanks, in particular to be moved simultaneously. With the scanning the support flanks measured in particular in their evenness and at a distance from each other. Appropriately, a supporting flank of an anchoring tooth is scanned with one scanning device.

In this way, with relatively little effort and quickly particularly reliable information about operational geometric changes or otherwise caused deviations, for example, from a target geometry, can be obtained for a particularly relevant area of a turbine blade, specifically on supporting flanks of a fir-tree Schaufelfußprofils. The data obtained according to the invention can then be used, for example, to carry out residual life estimates and / or to determine whether reinstallation of a blade which has been in operation is still possible, in particular if the foot is still inserted into a fastening groove, e.g. a wheel disc, can be used.

In the context of the method according to the invention, preferably at least a number of scanning devices are used, which corresponds to the number of anchoring teeth on one side of the generally symmetrical fir tree profile of the feet to be measured. Then, in one pass, the carrying flanks of all the anchoring teeth on the one side of a blade root can in particular be scanned simultaneously. Accordingly, in two scanning passes, specifically one for the one and one for the other side, a blade root can be completely measured in the manner according to the invention.

In addition to the scanning devices for several, in particular all teeth on the one side of a blade root, at least one reference scanning device may be provided, which is a reference surface, which is not defined in particular by a blade root to be measured, but separately to such - as a reference , scans, this in particular simultaneously with the scanning of the supporting flank (s). By scanning a reference surface device inaccuracies can be detected.

It may be provided that the blade root, after supporting flanks have been scanned by preferably all anchoring teeth on its one side, taken out of the tool holder, reversed and reinserted in the tool holder, and supporting flanks are scanned by preferably all teeth on its other side the scanning devices are again moved along the blade root in the longitudinal direction.

In a particularly preferred embodiment of the method according to the invention is further provided that the scanning of the support flanks is carried out with scanning devices which are arranged offset in a direction which is oriented at least substantially orthogonal to the longitudinal direction, wherein preferably the distance between adjacent scanning devices in this Direction is adapted to a predetermined distance of the support flanks of adjacent anchoring teeth in this direction. Alternatively or additionally, the scanning of the carrying flanks can be carried out with scanning devices which each comprise a scanning element to be brought into contact with a supporting flank or at least emit at least one laser beam to be directed onto a supporting flank, the scanning elements or scanning beams of adjacent scanning devices in a direction which is at least is oriented substantially orthogonal to the longitudinal direction, offset from one another, wherein preferably the distance of the scanning elements or laser beams of adjacent scanning devices in this direction is adapted to a predetermined distance of the support flanks of adjacent anchoring teeth in this direction. In particular, the scanning devices used and / or sensing elements, such as feeler lever or the like, or emitted laser beams may have a distance from each other in said direction, which corresponds to the nominal distance of the support flanks of the blade root, in particular in the unused state, ie the support edge nominal distance of Target geometry (without operational deformations). Starting from this "zero point" then deviations from the nominal geometry can be determined by scanning with each scanning device in a particularly simple manner, which is why a corresponding arrangement of the scanning has been found to be particularly suitable. Also can be determined in a particularly simple manner and in a measuring passage by the use of several, in particular adapted to the support edge spacing spaced scanning or scanning / laser beams, whether the distance of the support flanks to each other a desired distance or not, for example due to operational changes Has.

For example, inductive and / or laser-based scanning devices can be used for scanning the bearing flanks, with the first-mentioned variant in particular having proven particularly suitable. Among inductive scanning devices are mainly those to be acquired, which include a scanning that is moved to the tactile measurement of a support edge along this, and are detected by the position changes inductively. Laser-based scanners enable non-tactile optical scanning.

It should be noted that in the case of a tactile scan it may be provided that for sampling The sensing element used for the respective supporting flank is not in contact with the supporting flank to be measured all along the length of time that it slides along, but does not slide along the supporting flank at given measuring positions "point by point" during the process becomes. As a result, in particular the wear of the scanning elements used can be reduced. For the preferably motorized lifting and depositing of the respective scanning element during a scanning operation, suitable means are preferably provided. In this case, for example, the sensing element can be mounted motorized movable or there is a separate, with to-travel device for raising and lowering of the respective sensing element available.

The tool holder into which a blade root to be measured is to be used for the measuring process can be defined, for example, by a frame of the measuring device provided. The scanning in the longitudinal direction can then be carried out in particular by scanning means, which are arranged on a longitudinally movably held on the frame carriages, scan the supporting flanks, while the carriage in a corresponding direction - for example motorized or by hand - is moved.

• - ein Gestell, welches wenigstens eine Werkzeugaufnahme für einen Schaufelfuß mit tannenbaumförmigem Profil definiert, der eine Mehrzahl von sich in einer Längsrichtung erstreckenden, das tannenbaumförmige Profil bildenden Verankerungszähnen aufweist, die jeweils eine sich in Längsrichtung erstreckende insbesondere der Schaufelspitze zugewandte Tragflanke und eine gegenüberliegende, sich ebenfalls in Längsrichtung erstreckende Freiflanke definieren,
• - wenigstens einen an dem Gestell in Längsrichtung insbesondere linear verfahrbar gehaltenen Schlitten, an dem mehrere Abtasteinrichtungen voneinander beabstandet gehalten sind,
• - wobei die Abtasteinrichtungen derart ausgebildet und an dem Schlitten angeordnet sind, dass mittels dieser berührungslos und/oder berührungsbasiert mehrere Tragflanken eines in der Werkzeugaufnahme angeordneten Schaufelfußes mit tannenbaumförmigem Profil insbesondere simultan abtastbar sind, wenn der Schlitten in Längsrichtung entlang des Schaufelfußes verfahren wird und dabei mit den Abtasteinrichtungen Messwerte erfasst werden.

The inventive method can be carried out with a measuring device according to the invention, which comprises

• - A frame which defines at least one tool holder for a blade root with tannenbaumförmigem profile having a plurality of extending in a longitudinal direction, the fir tree-shaped profile forming anchoring teeth, each having a longitudinally extending in particular the blade tip facing support flank and an opposite, itself also define longitudinally extending free flank,
• at least one carriage, which is held linearly in particular in a linear manner on the frame, on which a plurality of scanning devices are held at a distance from one another,
• - Wherein the scanning devices are designed and arranged on the carriage, that by means of these contactless and / or touch-based multiple support edges of a tool holder in the blade root with fir-shaped profile are in particular simultaneously scanned, when the carriage is moved longitudinally along the blade root and with the scanning devices measured values are detected.

This structural design has proven to be particularly suitable. In this case, it may be provided that the scanning devices each have at least one, in particular elongate scanning element to be brought into contact with a blade root arranged in the tool holder, and are designed to detect a change in position of the scanning element, preferably inductively. The scanning devices are then arranged in particular on the carriage such that their preferably elongate scanning elements extend at least substantially parallel to one another. Then, in each case a scanning element, such as sensing lever, can be easily brought into abutment with one of the usually at least approximately parallel support flanks of the teeth on one side of a Schaufußes. The arrangement is then further preferably such that, when used as intended, at least one scanning element extends at least approximately parallel to a supporting flank against which it rests. The sensing elements may further be, for example, rod-shaped.

A further embodiment is characterized in that the scanning devices are each designed and arranged so that they can detect a change in position of the respective scanning element, such as sensing lever in a direction at least substantially orthogonal to the direction of travel of the carriage.

As already mentioned above, scanning devices which operate inductively can be used for the scanning process, with a position change of a scanning element, in particular, being detected inductively.

Alternatively or additionally, it may be provided that the scanning devices are designed and arranged to each emit at least one laser beam and to direct for scanning on an arranged in the tool holder fir-tree-shaped blade root, and to detect reflected and / or scattered laser light. The respectively emitted by the scanning each at least one laser beam then serves as an optical scanning beam, with which the course of the support flanks can be determined. If a laser-based scanning is provided, the measuring device according to the invention can furthermore be characterized in that the scanning devices are arranged in such a way that the at least one laser beam emitted by each of them at least substantially orthogonally on a supporting flank of a fir-tree-shaped blade root arranged in the receiving region is directed.

It should be noted that the scanners also fall into a larger overall Scanning device can be integrated. In particular, in the simplest case, a scanning device is a scanning element, such as feeler lever, and means for metrological registration of a particular change of position of the element caused externally or means for providing at least one (laser) Abtaststrahls and means for detecting a at one to be measured Surface reflected and / or scattered portion of the scanning comprises.

In a further development of the measuring device according to the invention, the at least one carriage is preferably held without play on the frame by means of one or more ball cage bearings. This type of storage provides particularly reliable and accurate readings, as inaccuracies that can be associated with a game, reliably avoided. Also, one or may - in particular in the case of several carriages - several traversing rails are used over which the / the slide is held in particular linearly movable on the frame / are.

In a further advantageous embodiment, suitable means are further provided to detect the current position of the at least one carriage movably held on the frame. These may, for example, comprise one or more ultrasound sensors held on the at least one carriage and / or the frame. Then, the current travel path can be detected metrologically via an ultrasonic transit time measurement and the scanning data acquired with the scanning devices can be assigned to those location coordinates in the longitudinal direction of the blade root on which they were detected. In particular, in the event that the at least one carriage is movably held on the frame via at least one movement rail, a position determination integrated into the movement rail (s) can also be provided. In the at least one travel rail, for example, a travel receiver may be integrated, which may be e.g. works optically.

Furthermore, it may be provided that the tool holder, in particular the frame defining it, is designed such that, when the device is used as intended, in particular when a blade root is inserted in the tool holder as intended, a blade root arranged therein is oriented substantially horizontally. This has proved to be particularly suitable, in particular, in order to position the supporting flanks of the anchoring teeth for a scanning easily accessible. The blade may then preferably be oriented such that the anchoring teeth present on two sides of the foot point up and down, with the upwardly facing teeth being scanned.

Also, at least one fixing element may be provided in the region of the tool holder, the outer contour of which is adapted at least in sections to a region of the outer contour of a fir-tree-shaped blade root. A fixing element may be provided, for example, in the form of one or more holding webs extending in particular in the longitudinal direction, which at least in sections are characterized by a cross section which can intervene in a positive or at least almost positive engagement with a depression defined between two adjacent anchoring teeth of a fir-tree-shaped blade root, and thus ensures a positioning of a blade root to be measured in the tool holder at a predetermined location. For example, a holding web, in particular on the upper side, have at least two supporting projections whose outer contour is adapted to a section of the inner contour of a depression formed between two anchoring teeth of the blade root to be measured.

According to a further particularly preferred embodiment of the measuring device according to the invention, the frame defines two tool holders for a respective fir tree-shaped blade root, so that a particularly simultaneous measurement of two blade roots in the manner according to the invention is possible. In this case, then preferably two on the frame in the longitudinal direction linearly held back and held movable carriage provided, on each of which a plurality of scanning devices are kept spaced from each other, and one of the two carriages is assigned to one of the two tool holders.

Another component of the measuring device according to the invention may be an evaluation unit, which preferably receives, stores and / or evaluates measured data acquired by the scanning devices. The evaluation unit may comprise a microcontroller and / or a serial interface. Furthermore, a control unit may be provided, which in particular controls the movement of the carriage. Data processing and control can also be taken over by a central control and evaluation unit.

It can also be provided that a measuring device according to the invention used is calibrated, in particular, with a blade root manufactured against nominal.

Another object of the invention is a system comprising a measuring device according to the invention at least one turbine blade with a fir-tree-shaped blade root to be measured. In the system according to the invention, the scanning devices are preferably on the arranged at least one carriage, that the distance of adjacent scanning devices in a direction which is oriented at least substantially orthogonal to the longitudinal direction, is adapted to a predetermined distance of the support flanks of adjacent anchoring teeth of at least one blade root to be measured in this direction. Alternatively or additionally, it may be provided that the scanning devices each comprise a scanning element to be brought into contact with a scanning element or at least emit at least one laser beam to be directed on a supporting flank, and are arranged on the carriage, that the distance of the scanning elements or emitted laser beams adjacent Scanning in a direction which is oriented at least substantially orthogonal to the longitudinal direction, is adapted to a predetermined distance of the support flanks of adjacent anchoring teeth in this direction.

It should be noted that, for a given type of bucket with a fir-tree-shaped blade root to be measured, a measuring device according to the invention which is adapted to the concrete shape of the fir-tree blade root is expediently used. In particular, the at least one tool holder is adapted in its shape and dimensioning to the shape and dimensions of the blade root type to be measured and the scanning devices are designed and arranged such that the scanning elements of these or their scanning beams are oriented or emitted accordingly, that a scanning of support flanks of a blade root of the corresponding type is possible if it is positioned as intended in the tool holder.

• 1 eine schematische Seitenansicht eines ersten Ausführungsbeispiels einer erfindungsgemäßen Messvorrichtung sowie eine Turbinenschaufel mit zu vermessendem Schaufelfuß;
• 2 eine vergrößerte Teilansicht der Messvorrichtung aus 1 von der Seite;
• 3 eine vergrößerte Teilansicht der Messvorrichtung aus 1 von schräg oben;
• 4 eine vergrößerte Teilansicht der Messvorrichtung aus 1 von oben;
• 5 eine vergrößerte Teilansicht der Messvorrichtung aus 1 von vorne;
• 6 eine schematische Ansicht eines zweiten Ausführungsbeispiels einer erfindungsgemäßen Messvorrichtung von schräg oben;
• 7 eine schematische Teilansicht eines dritten Ausführungsbeispiels einer erfindungsgemäßem Messvorrichtung von oben; und
• 8 eine schematische Teilansicht nur des Gestells des zweiten Ausführungsbeispiels; und
• 9 eine schematische Teilansicht der zweiten Ausführungsform einer erfindungsgemäßen Messvorrichtung mit teilweise transparent dargestellten Komponenten.

Further features and advantages of the present invention will become apparent from the following description of four embodiments of a measuring device according to the invention and the method according to the invention with reference to the drawings. That's it

• 1 a schematic side view of a first embodiment of a measuring device according to the invention and a turbine blade with blade root to be measured;
• 2 an enlarged partial view of the measuring device 1 of the page;
• 3 an enlarged partial view of the measuring device 1 from diagonally above;
• 4 an enlarged partial view of the measuring device 1 from above;
• 5 an enlarged partial view of the measuring device 1 from the front;
• 6 a schematic view of a second embodiment of a measuring device according to the invention obliquely from above;
• 7 a schematic partial view of a third embodiment of an inventive measuring device from above; and
• 8th a schematic partial view of only the frame of the second embodiment; and
• 9 a schematic partial view of the second embodiment of a measuring device according to the invention with partially transparent components shown.

The 1 shows a first embodiment of a measuring device according to the invention 1 , by means of a fir-tree-shaped blade root 2 a turbine blade 3 can be measured. Various enlarged partial views of the device 1 can the 2 to 5 be removed.

In the figures, the device is 1 together with a turbine blade 3 with a blade foot to be measured 2 shown. The shovel 3 , which in this case is a blade, includes next to the fir-tree-shaped foot 2 in a known manner a platform 4 and an airfoil 5 , The measuring device 1 and the turbine blade 3 also represent an embodiment of a system according to the invention.

The fir-tree-shaped foot to be measured 3 has, in a well-known manner, a plurality of anchoring teeth extending in a longitudinal direction 6 on, each also extending in the longitudinal direction, the blade tip 7 facing supporting flank 8th and an opposite, also in the longitudinal direction extending free flank 9 define. The longitudinal direction is present in the 1 labeled x Direction given perpendicular to the plane of the drawing 1 is oriented. In the illustrated example, the blade root 2 a total of six anchoring teeth 6 on each of which three on one side of the foot 2 lie. In concrete terms, there are two mirror-inverted anchoring teeth each 6 arranged opposite each other and there is a symmetrical Christmas tree profile. Between every two adjacent anchoring teeth 6 is also a longitudinally extending recess 10 educated. The fir tree-shaped blade foot 2 serves in a well-known manner the attachment of the turbine blade 3 on the shaft of a turbine, such as a wheel disc (not shown in the figures) leading to the pine tree foot 2 correspondingly shaped, extending in the axial direction of the turbine mounting grooves, in which the blades 3 be inserted in the axial direction.

In operation of the turbine are subject to the blades 3 high loads, such as centrifugal forces and deformations can occur.

In particular for the reliable prediction of the further usability and / or remaining life of previously operated turbine blades 3 It may be necessary after a certain period of operation, the blade root 2 to measure.

Reliable data on the geometry of a blade root to be measured 2 can be carried out using the method according to the invention using in the 1 to 5 illustrated embodiment of a measuring device 1 to be obtained.

This includes a frame 11 , which in the illustrated embodiment by an approximately L -shaped cross-sectional shape, wherein the long leg 12 on the background, not shown in the figures rests flat and the short leg 13 approximately perpendicular to the top of the long leg 12 protrudes, concretely with the long thigh 12 an angle of slightly more than 90 °. In cross section (see in particular 1 ) the long leg tapers 12 in the longitudinal direction of the blade tip 7 down, so in the short thigh 13 opposite direction. The frame 11 has in the illustrated embodiment, a longitudinal direction, ie in x Direction, constant cross-sectional shape. It is further characterized by an extension in the longitudinal direction, which is the extension of the device 1 to be measured blade foot 2 exceeds (see in particular the enlarged supervision 4 ).

From the frame 11 becomes, as recognizable in the figures, a tool holder 14 for a fir tree-shaped blade foot 2 Defines this over an area that is on the inside 15 of the short thigh 13 begins and extends in the z direction over about one third of the total extent of the long thigh 12 extends in this direction. In the area of the tool holder 14 is a longitudinal direction over the entire extent of the frame 11 extending in this direction holding bridge 16 intended. This has on the upper side at two longitudinally spaced locations supporting projections S, which in its outer contour to that recess 10 that between the first, from the blade tip 7 furthest anchoring tooth 6 and the middle anchoring tooth adjacent thereto 6 is formed, adapted. The support projections S are in the 1 to 5 not visible. The 8th which is a partial representation of the frame only 11 without recorded blade foot 2 shows, and the 9 in which blade foot 2 and sledges 19 are transparent, the support projections S can be removed, it being noted that these figures relate to the second embodiment described below, in which the frame 11 and the sled 19 are slightly different. In the embodiment of the 1 to 5 are two equally shaped support projections S at corresponding points on the to the frame 11 molded retaining bar 16 intended.

Is a fir tree-shaped blade foot 2 , as shown in the figures, in the tool holder 14 used, grab the two at the jetty 16 molded support projections S almost positively or positively in the depression 10 one and the blade foot 2 becomes reliable at a given measuring position in the tool holder 14 held. The support on the two support projections S and not on the entire jetty 16 , so only in two places avoids an "overdetermined" storage and in particular a tilt or wobble in the case of a deformed depression 10 , For a particularly reliable positioning, the two support projections S Provided at positions that are widely spaced apart from one another in the longitudinal direction are located concretely near the longitudinal end regions of the tool holder 14 ,

The positioning at the predetermined measuring position is in the illustrated embodiment, also on the inside 15 of the short thigh 13 of the frame 11 achieved, because the lower, facing away from the blade tip end face of the foot 2 lies, as can be seen in particular in Figure, flush on this page 15 of the short thigh 13 on, when the blade foot 2 in the tool holder 14 is used. Finally the shovel lies 3 for positioning with one end face 17 the platform 4 , specifically the in 1 down facing end face 17 the platform 4 on the inside 18 of the long thigh 12 on. The rejuvenation of the long thigh 12 in the direction of the blade tip 7 carries the larger width (extension in y Direction) of the platform 4 opposite the blade foot 2 Invoice.

The measuring device 1 further comprises according to the invention a carriage 19 who is on the rack 11 longitudinal ( x Direction) is movable and three scanning devices 20 wears on the sledge 19 in a direction orthogonal to the longitudinal direction oriented spaced from each other on the carriage 19 are held.

The movable storage of the carriage 19 on the frame 11 is in the illustrated embodiment via two longitudinally extending ball cage guides 21 realized. About the ball cage guides 21 becomes the sled 19 free of play on the frame 11 guided. The process of the sled 19 for a measuring process motorized with an unrecognizable in the figures engine. As an alternative to the embodiments shown here with motorized movable carriage 19 can also be provided that the carriage 19 by hand, in which case can be dispensed with the engine.

As can be seen in the figures, the carriage stands out 19 similar to the frame 11 - By a roughly L-shaped cross-sectional shape with a short 22 and a long thigh 23 out, taking from the two thighs 22 . 23 however, in deviation of a classic L 's - an angle of about 135 ° clearly deviating from 90 ° is included. At the blade foot to be measured 2 facing inside 24 is the short thigh 22 of the sled 19 for proper positioning of the three scanners 20 relative to the support flanks 8th the anchoring teeth 6 stepped.

The sled 19 stands out, likewise in analogy to the Gesell 11 by a longitudinally constant cross-sectional shape, with the exception of a lower-side projection 25 is given (see in particular the view from 5 ), which forms an incident surface for ultrasonic waves, which from on the frame 11 held, the positioning of the carriage 19 on the frame 11 serving ultrasonic sensors 26 be emitted in the longitudinal direction. By emitting ultrasonic waves by means of the sensors 26 and transit time measurement of the projection 25 reflected or scattered signal, the current distance between the sensors 26 and the facing the impact surface of the projection 25 measured and so on the current position of the carriage 19 be closed in the longitudinal direction.

With the three of the sledge 19 worn scanners 20 these are inductive scanning devices. Concretely, each scanning device comprises 20 a rod-shaped feeler lever 27 , on each of a supporting flank of the anchoring teeth 6 rests on one side of the fir-tree-shaped profile when a blade root to be measured 2 in the tool holder 14 is used, as in the 1 to 5 recognizable. The presently identical scanning 20 are designed such that a deflection, specifically a swinging out of their feeler lever 27 in a direction to the longitudinal direction ( x Direction) orthogonal plane around the suspension point 28 of the respective feeler lever - opposite to in 1 recognizable starting position of the feeler lever 27 - Inductively via corresponding, not visible in the figures means of the respective scanning device 20 is measurable. In the illustrated embodiment, the scanning devices 20 by inductive measuring probes of the Millimar type 1318 given from the House of Mahr. These are well suited, inter alia, due to their size for use in the context of the measuring device according to the invention, it being emphasized that, of course, other scanning devices 20 Can be used.

The scanning devices 20 are further, as seen in the figures, offset in a direction which is oriented at least substantially orthogonal to the longitudinal direction, offset from one another. The arrangement is concretely such that the distance of the feeler lever 27 adjacent scanning devices 20 in this direction the distance of the supporting flanks 8th adjacent anchoring teeth 6 in this direction corresponds (see in particular the enlarged side view from 2 ).

Each of the inductive scanning devices 20 is with only one in the 1 illustrated control and evaluation 29 the measuring device 1 connected. Also connected to this are the ultrasonic sensors 26 , The control and evaluation unit 29 controls the movement of the carriage 19 for a measurement process and gets, during a measurement process from the ultrasonic sensors 26 recorded readings and from the three scanners 20 recorded measured values, stores them and processes them. The control and evaluation unit 29 includes a microcontroller for this purpose.

A measurement of a fir-tree-shaped blade root 2 performing an embodiment of the method according to the invention using the in the 1 to 5 shown device 1 will be described in more detail below.

After a fir tree-shaped blade foot to be measured 2 in the tool holder 14 the device 1 was used, as it is in the 1 to 5 is shown, the carriage is 19 , Which is in the initial state at one end of its travel in the longitudinal direction, once over the entire extent of the blade root 2 moved in the longitudinal direction. In the process, measured values are taken from the ultrasonic sensors 26 and the scanners 20 , their feeler lever 27 when the blade foot 2 at the predetermined position in the tool holder 14 is arranged, with the support flanks 8th of the three anchoring teeth 6 on one side of the foot 2 in contact with the control and evaluation unit 29 to hand over.

There are digital readings of the scanning devices 20 as a function of the blade root length, that is to say the position of the latter in the longitudinal direction, the signals of which are specifically read out by the microcontroller and transmitted via the ultrasonic sensors 26 received, also read by the microcontroller data linked. The microcontroller then sends the data to a serial interface, which makes the recorded data analyzable, in particular graphically and numerically representable.

It can be provided in particular that the measuring device 1 previously with a manufactured against Nominal, not yet been in operation blade root 2 same design was calibrated. In this case, deviation values from the nominal geometry can be detected directly.

After the support flanks 8th the anchoring teeth 6 on one side of the foot 2 were measured in the manner described above, the blade 3 simply removed from the tool holder rotated 180 ° and reinserted so that the support flanks 8th the teeth 6 accessible on the other and with the feeler levers 27 the scanning devices 20 can be sampled.

Detected deviations are then preferably analyzed and used for finite element method calculations, such as for residual life evaluation.

The procedure according to the invention makes it possible to reliably obtain data about the geometry of a fir tree-shaped blade root 2 be obtained in a particularly simple manner, in particular with comparatively little time. The supporting flanks 8th be in their flatness and - because three scanning devices with adapted to the support edge distance spaced sensing levers 27 be used - measured in their distance from each other.

In the 6 is a second embodiment of a device according to the invention 1 which differs from the first embodiment described above substantially in that it is for simultaneous measurement of two blade roots 2 is trained. Identical or corresponding components are provided with the same reference numerals.

In particular, the frame 11 the in 6 The device shown differs in its shape and size from that of the device 1 , This one is bigger and defines two tool holders 14 , in the two shovel feet 2 can be used side by side. The frame 11 The second embodiment also does not have an overall longitudinally consistent cross-sectional shape. This applies only to a blade foot near part 30 of the frame 11 , which is below the two tool holders 14 extends. At this is an orthogonal to the longitudinal direction, specifically in z Direction extending stabilizer rail 31 , in the present case with T-profile, fixed, the length of which the radial extent of the blades 5 the blades 3 just below. Of course, stabilizing rails with other profile shapes can also be used. Like from the 6 shows is for particularly reliable positioning of in the tool holder 14 arranged blade feet 2 next to the jetty 16 with in the area of each of the two tool holders 14 two each from the jetty 16 protruding from the top, in their shape to the recess 10 adapted support projections S another in shape to the blade foot to be measured 2 adjusted level 32 provided, which is inserted with blade root 2 below or in the horizontal orientation of the blades in z Direction in front of the platform 4 extends.

There are also two slides 19 each with three held inductive scanning 20 provided, each with a carriage 19 a tool holder 14 is assigned and the measurement of a blade root 2 serves. The scanning devices 20 are to those of the embodiment of the 1 to 5 identical.

The sled 19 The second embodiment is noticeably characterized by a slightly different shape. The scanning devices 20 however, with these at the same positions relative to a blade root to be measured 2 in the respective tool holder 14 held. The longitudinally movable mounting of the respective carriage 19 on the frame 11 Here is also about a respective carriage 19 assigned travel rail 33 realized that on the frame 11 is fixed. Because the travel rails 33 each have an unrecognizable in the figures integrated optical path recording are in this embodiment, no ultrasonic sensors 26 intended for the carriage position determination.

The inventive scanning of the supporting flanks 8th is exactly as described above for the first embodiment, but with the two feet 2 measured simultaneously, so the two sledges 19 be moved simultaneously in the longitudinal direction for Tragflankenabtastung.

In analogy to the first embodiment, the blades are also here 3 after scanning the three supporting flanks 8th on one side of the foot 2 taken out, turned over, put back in place and then measured the other side in the same way as the first one.

In the 7 is a third embodiment of a measuring device according to the invention 1 purely schematically and greatly simplified shown in the plan. This differs from the first and second embodiments in that instead of inductive scanning laser-based sampling 20 are provided. These have no feeler lever 27 for tactile scanning, but are designed to each have a plurality of laser scanning beams 33 to emit and laser light which is on the supporting flanks to be scanned 8th impinges and (diffuse) is reflected or scattered, to detect and draw conclusions about the position of the reflection surface from the detected light, in particular to determine the distance to reflection points. For detection, each scanner comprises 20 in a conventional manner a suitable detector. For the optical scanning of the supporting flanks 8th For example, use can be made of laser triangulation or any other laser-based methods which make it possible.

A scanning process of the supporting flanks 8th first of the three anchoring teeth 6 on one side and then the other side of the foot 2 is performed in the same manner as described above for the first and second embodiments, with the only difference that here the sample measurement data is obtained by non-tactile optical scanning.

It should be noted that in the simplistic 7 neither the frame 11 , nor the sled 19 the measuring device are shown, since only the other optical scanning principle should be clarified. All not shown components may be configured, for example, as in the first or second embodiment described above.

The 8th and 9 show, as already noted above, further partial views of the second embodiment of a measuring device according to the invention, from which also the position and configuration of the support projections S emerge. For all the embodiments described above, it should also be noted that the respective device 1 recognizable by the concrete shape of the fir-tree blade root to be measured shown in the figures 2 is adjusted. In this case, in particular, the at least one tool holder 14 in their shape and their dimensions to be measured blade feet 2 customized. Also the at least one sled 19 and the arrangement of the scanning devices 20 these are the blade feet to be measured 2 adjusted so that the feeler lever 27 in contact with supporting flanks 8th can come if they are intended in the tool holder 14 are used, or - in the case of laser-based scanning - so that the emitted laser radiation, the support flanks 8th then hits as intended. The number of scanners 20 is also the number of anchoring teeth 6 on one side of the foot 2 customized.

Although the invention has been further illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2322764 A1 [0002]

Claims (15)

Method for measuring a fir-tree-shaped blade root (2) of a turbine blade (3), which has already been in operation in particular, in which - a blade root (2) to be measured with a fir-tree-shaped profile, which has a plurality of anchoring teeth (6) which extend in a longitudinal direction and form the fir-tree-shaped profile, each having a supporting flank (8) extending in the longitudinal direction, in particular of the blade tip (7). and defining an opposite, also longitudinally extending free flank (9) is provided, the fir tree-shaped blade root (2) is inserted into a tool receptacle (14) of a provided measuring device (1), - With several, in particular at least one of the number of anchoring teeth (6) on one side of the fir tree-shaped blade root (2) corresponding number of scanning devices (20) the support flanks (8) of several, in particular all teeth (6) on one side of the fir-tree-shaped blade root (2), the scanning devices (20) preferably being moved along the blade root (2) at the same time in the longitudinal direction and measuring values being recorded with the scanning devices (20). Method according to Claim 1 , characterized in that the scanning of the carrying flanks (8) is carried out with scanning devices (20) which are arranged offset in relation to one another in a direction which is oriented at least substantially orthogonally to the longitudinal direction, the distance between adjacent scanning devices (20) preferably being in this direction is adapted to a predetermined distance of the supporting flanks (8) of adjacent anchoring teeth (6) in this direction, and / or the scanning of the supporting flanks (8) is carried out with scanning devices (20) each with a supporting flank (8). or at least one laser beam to be directed onto a support flank (8), the scanning elements or scanning beams of adjacent scanning devices (20) being offset in a direction oriented at least substantially orthogonally to the longitudinal direction , wherein preferably the distance of the scanning elements (27 ) or laser beams (34) of adjacent scanning devices (20) in this direction to a predetermined distance of the support flanks (8) of adjacent anchoring teeth (6) is adapted in this direction. Method according to Claim 1 or 2 , characterized in that the blade root (2), after support flanks (8) were scanned by anchoring teeth (6) on its one side, taken out of the tool holder (14), reversed and re-inserted into the tool holder (14), and supporting flanks (8) of teeth (6) are scanned on its other side, wherein the scanning means (20) for this purpose along the blade root (2) are moved in the longitudinal direction. Method according to one of the preceding claims, characterized in that inductive and / or laser-based scanning devices (20) are used for the scanning. Method according to one of the preceding claims, characterized in that the blade root (2) to be measured is inserted into a tool holder (14) defined by a frame (11) of the provided measuring device (1), and the scanning is carried out with scanning devices (20), which are held on at least one longitudinally movable on the frame (11) held carriage (19). Measuring device (1) for carrying out the method according to one of the preceding claims, comprising - a frame (11) which defines at least one tool holder (14) for a blade root (2) with Tannenbaumförmigem profile having a plurality of extending in a longitudinal direction, the fir-tree-shaped profile forming anchoring teeth (6), each one in Define longitudinally extending, in particular the blade tip (7) facing support flank (8) and an opposite, also in the longitudinal direction extending free edge (9), - At least one on the frame (11) in the longitudinal direction, in particular linearly movable held carriage (19) on which a plurality of scanning devices (20) are held spaced from each other, - Wherein the scanning devices (20) are formed and arranged on the carriage (19) that by means of this contactless and / or touch-based plurality of support flanks (8) in the tool holder (14) arranged blade root (2) with Tannenbaumförmigem profile scanned in particular simultaneously are when the carriage (19) in the longitudinal direction along the blade root (2) is moved and thereby measured values are detected with the scanning devices (20). Device (1) according to Claim 6 , characterized in that the scanning devices (20) with a in the tool holder (14) arranged blade root (2) to be brought into contact, in particular elongated sensing element (27), and are adapted to a change in position of the Preferably, the scanning devices (20) are preferably arranged such that their particular elongated sensing elements (27) extend at least substantially parallel to each other. Device (1) according to Claim 7 , characterized in that the scanning devices (20) are each designed and arranged such that they can detect a change in position of the respective scanning element (27) in an at least substantially orthogonal to the direction of travel of the carriage (19) direction. Device (1) according to Claim 6 , characterized in that the scanning means (20) are formed and arranged to each emit at least one laser beam (34) and to scan to a in the tool holder (14) arranged fir tree-shaped blade root (2), and to reflected and / or to detect scattered laser light. Device (1) according to Claim 9 , characterized in that the scanning devices (20) are arranged in such a way that the at least one laser beam (34) emitted by the device (1) is at least substantially orthogonal to a supporting flank (8) in the tool holder (14) ) arranged fir tree-shaped blade root (2) is directed. Device (1) according to one of Claims 6 to 10 , characterized in that means for detecting the position of the at least one carriage (19) on the frame (11) are provided, in particular at least one, preferably more held on the at least one carriage (19) and / or the frame (11) Ultrasonic sensors (26) include. Device (1) according to one of Claims 6 to 11 , characterized in that the at least one carriage (19) by means of one or more ball cage bearings (21) preferably without play on the frame (11) is movably held. Device (1) according to one of Claims 6 to 12 , characterized in that the tool holder (14), in particular the frame (11) defining it, is designed such that, when the device (1) is used as intended, a blade root (2) arranged in the tool holder (14) is aligned at least substantially horizontally , and / or in the region of the tool holder (14) at least one fixing element (16) is provided whose outer contour is at least partially adapted to a region of the outer contour of a fir-tree-shaped blade root (2). Device (1) according to one of Claims 6 to 13 , characterized in that the frame (11) defines two tool holders (14) for each fir-tree-shaped blade root (2) of a turbine blade (3), and in particular two carriages (19) held on the frame (11) in the longitudinal direction, in particular linearly displaceable, at each of which a plurality of scanning devices (2) are held spaced apart, are provided, and in each case a carriage (19) is associated with a tool holder (14). System comprising a measuring device (1) according to one of Claims 6 to 14 and at least one turbine blade (3) having a fir-tree-shaped blade root (2) to be measured, wherein in particular the scanning devices (20) are arranged on the at least one carriage (19) such that the spacing of adjacent scanning devices (20) in a direction which is at least is oriented substantially orthogonal to the longitudinal direction is adapted to a predetermined distance of the support flanks (8) of adjacent anchoring teeth (6) of the at least one blade root (2) to be measured in this direction, and / or the scanning devices (20) each with a Supporting edge (8) to be brought into contact scanning element or each emitting at least one on a support edge (8) to direct laser beam, and are arranged on the carriage (19), that the distance of the scanning elements or emitted laser beams of adjacent scanning devices (20) in a direction at least substantially orthogonal to the longitudinal direction ori is entiert, is adapted to a predetermined distance of the support flanks (8) of adjacent anchoring teeth (6) in this direction.

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