MACHINING APPARATUS AND METHOD FOR MACHINING THE OUTER CIRCUMFERENCE OF A ROTOR BY USING SUCH AN APPARATUS

Abstract

A machining apparatus which is designed for machining the outer circumference of a rotor, in particular of a gas-turbine or steam-turbine rotor, includes a plurality of separate carriages, at least one tensioning strap, wherein the carriages can be connected to one another to create an annular arrangement, and also having a tensioning device, in particular in the form of a pressure ratchet, which is designed for tensioning the tensioning strap. The carriages are each provided with preferably floating-mounted wheels, which are oriented in a direction of travel, and wherein at least one carriage has a tool carrier for accommodating a machining tool and driving it by motor. A method for machining the outer circumference of a rotor by using such a machining apparatus is provided.

Claims

1. A machining apparatus which is designed for machining an outer circumference of a rotor, in particular of a gas turbine or steam turbine rotor, comprising: multiple separate carriages, at least one lashing strap adapted to connect the carriages to one another to create a ring-shaped arrangement, and a tensioning device, in particular in the form of a push-type ratchet, which is designed for tensioning the lashing strap, wherein the carriages are each equipped with preferably floatingly mounted wheels which are oriented in a direction of travel, and wherein at least one carriage has a tool carrier for receiving a machining tool and for driving said machining tool by a motor.

2. The machining apparatus as claimed in claim 1, wherein at least some carriages are equipped with a lashing strap guide surface that is formed by a lashing strap guide roller.

3. The machining apparatus as claimed in claim 2, wherein at least some carriages comprise at least one clamping jaw which is movable between a release position and a clamping position and which has a clamping surface, wherein the clamping surface, in the clamping position, presses in the direction of the lashing strap guide surface such that the lashing strap placed between the lashing strap guide surface and the clamping surface is secured by clamping action.

4. The machining apparatus as claimed in claim 1, wherein at least some carriages have a frame to which the wheels are rotatably fastened.

5. The machining apparatus as claimed in claim 4, wherein said machining apparatus has weights which are in particular of plate-like form, and wherein the shape and size of the weights are adapted to the shape and size of the frame such that the weights can be placed preferably form-fittingly into the frame.

6. The machining apparatus as claimed in claim 5, wherein the weights are equipped with at least one through bore for receiving a securing screw which, after the one or more weights have been placed into a carriage, is detachably connectable to the frame of the corresponding carriage.

7. The machining apparatus as claimed in claim 1, wherein at least some carriages have handles.

8. The machining apparatus as claimed in claim 1, wherein the tool carrier has advancing devices, which are in particular actuatable by handwheels, for at least radially and axially advancing the machining tool, wherein at least one advancing device is preferably equipped with a display device that indicates a present advancement value.

9. The machining apparatus as claimed in claim 1, wherein the machining tool is a side-milling cutter.

10. The machining apparatus as claimed in claim 1, further comprising: a suctioning device an intake opening of which is positioned adjacent to the machining tool.

11. The machining apparatus as claimed in claim 1, wherein the carriage that receives the tool carrier is equipped with at least two track blocks which protrude radially outwardly from the carriage and which are adjustable in an axial direction and which are in alignment with one another.

12. The machining apparatus as claimed in claim 1, further comprising: a measuring device that indicates a present tension force of the lashing strap.

13. The machining apparatus as claimed in claim 1, wherein said machining apparatus has steel cables that are designed to connect adjacent carriages in order to secure same.

14. The machining apparatus as claimed in claim 1, wherein at least eight carriages are provided.

15. The machining apparatus as claimed in claim 1, wherein at least one carriage has a feed device, actuation of which causes the carriage to be moved in a forward and/or backward direction of travel.

16. The machining apparatus as claimed in claim 15, wherein the feed device has friction wheels that are drivable via a belt drive that is actuatable by a handwheel.

17. The machining apparatus as claimed in claim 16, further comprising: at least one lifting device which is in particular actuatable by a hand lever and actuation of which enables the friction wheels to be moved selectively forward and backward in a radial direction.

18. A method for machining an outer circumference of a rotor, in particular of a gas or steam turbine rotor, the method comprising: providing a machining apparatus as claimed in claim 1, arranging the carriages, which have been connected to one another by the at least one lashing strap, such that the carriages are positioned on the rotor, as far as possible at uniform intervals in a circumferential direction in a rotor region that is to be machined, tensioning the lashing strap until a predetermined tension force is attained, and machining the rotor using the machining tool.

19. The method as claimed in claim 18, wherein a feed direction of the machining tool during the machining is realized by manual movement of the carriage in the circumferential direction of the rotor.

20. The method as claimed in claim 18, wherein the carriage that is situated opposite the carriage comprises the tool carrier that is equipped with weights.

21. The method as claimed in claim 18, wherein said method is carried out in situ at an installation site of the machine that has the rotor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further features and advantages of the present invention will become clear from the following description of an embodiment of the invention with reference to the appended drawing, in which:

[0027] FIG. 1 shows a perspective view of a machining apparatus according to an embodiment of the present invention;

[0028] FIG. 2 shows an enlarged perspective view of a subregion of the machining apparatus illustrated in FIG. 1;

[0029] FIG. 3 shows a perspective view showing different carriages of the machining apparatus illustrated in FIG. 1;

[0030] FIG. 4 shows a perspective side view of a carriage, which has a tool carrier, of the machining apparatus illustrated in FIG. 1;

[0031] FIG. 5 shows a further perspective side view of the carriage shown in FIG. 4;

[0032] FIG. 6 shows a perspective view from below of the carriage shown in FIG. 4;

[0033] FIG. 7 shows a perspective side view of a further carriage of the machining apparatus illustrated in FIG. 1;

[0034] FIG. 8 shows a perspective side view of the carriage illustrated in FIG. 7, with weights received therein;

[0035] FIG. 9 shows a view from below of the arrangement illustrated in FIG. 8;

[0036] FIG. 10 shows a perspective side view of a further carriage of the machining apparatus illustrated in FIG. 1, which has a lifting device which is actuatable by means of a hand lever and actuation of which enables friction wheels to be moved selectively forward and backward in a radial direction, wherein the hand lever is situated in a first position;

[0037] FIG. 11 shows a perspective view of the carriage illustrated in FIG. 10, with the hand lever situated in a second position;

[0038] FIG. 12 shows a side view of the arrangement illustrated in FIG. 11;

[0039] FIG. 13 shows a perspective partial view of a gas turbine, with an upper gas turbine half having been removed, and with the machining apparatus shown in FIG. 1 having been assembled on the rotor of the gas turbine;

[0040] FIG. 14 shows an enlarged perspective partial view of the arrangement illustrated in FIG. 13;

[0041] FIG. 15 shows an enlarged perspective plan view of a subregion of the detail illustrated in FIG. 13; and

[0042] FIG. 16 shows a side view of the arrangement illustrated in FIG. 15.

DETAILED DESCRIPTION OF INVENTION

[0043] The directional terms axial direction, radial direction and circumferential direction used below relate to the rotor that is to be machined, as shown in FIG. 13.

[0044] FIGS. 1 to 12 show a machining apparatus 1 according to an embodiment of the present invention, or components thereof. The machining apparatus 1 serves for machining the outer circumference of a rotor, as will be discussed in more detail below with reference to FIGS. 13 to 15. Said machining apparatus comprises, as main components, multiple separate carriages 2, a lashing strap 3 by means of which the carriages 2 can be connected to one another to create a ring-shaped arrangement, as illustrated in FIGS. 1 and 2, and a tensioning device 4 which is designed for tensioning the lashing strap 3 and which in the present case is in the form of a push-type ratchet.

[0045] The machining apparatus 1 illustrated in FIG. 1 has a total of eight carriages 2, wherein it is pointed out that, in principle, the number of carriages 2 is variable. Each carriage 2 has a frame 5, which is formed in the present case by in each case four laterally arranged frame elements 6 that are connected to one another via connecting struts 7. In each case two wheels 7 are held rotatably between two frame elements 6. The wheels are preferably floatingly mounted in order to allow a certain degree of axial play in an axial direction A. Furthermore, all of the carriages are equipped with a lashing strap guide surface 9 which, in the embodiment illustrated, is formed in each case by a lashing strap guide roller 10 mounted rotatably on the frame 5 in the upper region of the carriage 2. Advantageously, seven of the eight carriages 2 comprise in each case one clamping jaw 12 which is movable between a release position and a clamping position and which has a clamping surface 11, wherein the clamping surface 11, in the clamping position, presses in the direction of the lashing strap guide surface 9 such that the lashing strap 3 placed between the lashing strap guide surface 9 and the clamping surface 11 is secured by clamping action. Furthermore, in the present case, each carriage 2 is equipped with at least one handle that is fastened to the associated frame 5.

[0046] As shown in FIGS. 3 to 6, one of the carriages 2 has a tool carrier 14 that is designed for receiving a machining tool 15 and for driving said machining tool by motor means, wherein the machining tool 15 is formed in the present case by a side-milling cutter. The tool carrier 14 that is fastened to the frame 5, said frame being formed in the present case by rectangular frame elements 6, comprises advancing devices 17, 18 which are actuatable by means of handwheels 16 and by which the machining tool 15 can be advanced in a radial direction R and in an axial direction A. The advancing device 18 for the radial advancing movement is equipped with an indicator device 19 which indicates the present advancement value, and which in the present case is designed as an indicator dial. An intake opening 20 of a suctioning device 21 of the machining apparatus 1 is positioned adjacent to the machining tool 15 in order to suction away chips that are formed during the machining. Furthermore, on the carriage 2 that receives the tool carrier 14, there are in this case provided two track blocks 22 which protrude outwardly in a radial direction R and which are adjustable in an axial direction A and which are in alignment with one another. The free ends of the two lashing strap parts of the lashing strap 3, which each form a loop, are laid around the lashing strap guide rollers 10 positioned at the end sides on the carriage 2, and are thus fastened to the carriage 2. The lashing strap guide rollers 10 can be released in order to allow the lashing strap 3 to be installed and uninstalled.

[0047] Five further carriages 2, one of which is illustrated in detail in FIG. 3 and in FIGS. 7 to 9, serve in this case merely as running and lashing strap diverting carriages. The frames 5 of these carriages 2 are formed in the present case by triangular frame elements 6 and can optionally receive weights 23 of plate-like form, the shape and size of which are adapted to the shape and size of the frame 5 such that the weights 23 can be placed form-fittingly into the relevant frame 5. The weights are each equipped with a through bore 24 for receiving a securing screw 25 which, after the one or more weights 23 have been placed into a carriage 2, can be detachably connected to the frame 5 of the corresponding carriage 2 in order to fasten the weights 23 to the frame 5, as illustrated in FIGS. 8 and 9.

[0048] Two further carriages 2 of the machining apparatus 1, the frames 5 of which are in this case likewise formed by triangular frame elements 6, have a feed device 26 as illustrated in FIG. 3 and in FIGS. 10 to 12, actuation of which feed device causes the corresponding carriage 2 to be moved in a forward and/or backward direction of travel or circumferential direction U. The feed device 26 in this case comprises friction wheels 27 that are drivable via a belt drive 29 that is actuatable by means of a handwheel 28. Furthermore, a lifting device 31 is provided which is actuatable by means of a hand lever 30 and actuation of which enables the friction wheels 27 to be moved selectively forward and backward in a radial direction R in order to set the friction wheels 27 down on, or lift said friction wheels off from, a rotor that is to be machined.

[0049] The free ends of the two lashing straps 3 can be detachably connected to one another in a known manner by means of the tensioning device 4.

[0050] The machining apparatus 1 furthermore in this case has a measuring device 32 that indicates the present tension force of the lashing strap 3, said tension force being imparted by means of the tensioning device 4.

[0051] As further components, the illustrated machining apparatus has sixteen steel cables 33, of which in each case two steel cables 33 connect adjacent carriages 2 to one another in order to additionally secure them.

[0052] FIGS. 13 to 16 show a gas turbine 34 that has a rotor 35 comprising multiple turbine wheel disks 36. In the case of the gas turbine 34, cooling air leaks have occurred at one of the turbine wheel disks 36 during operation. Said leaks occur between sealing plates (not illustrated in any more detail in the figures) and the corresponding turbine wheel disk 36. To eliminate the cooling air leaks, it is sought to insert an additional sealing strip. For this purpose, an existing groove 37 into which the sealing plates of the additional sealing strip are to be inserted must be deepened by approximately 1.5 mm in the radial direction R. It is sought to deepen the groove 37 on an installed rotor 35, in situ at the installation site of the gas turbine 34, by machining using the machining apparatus 1 illustrated in FIGS. 1 and 2. For this purpose, in a first step, the upper turbine housing half of the turbine housing 38 that houses the rotor region that is to be machined is lifted off, and the turbine stator blade carrier is uninstalled, as shown in FIG. 13, in order to allow access to the rotor region that is to be machined. In a further step, the carriages 2 that are connected to one another via the steel cables 33 and the lashing strap 3 are arranged such that the individual carriages 2 are positioned in alignment, and as far as possible at uniform intervals, in a circumferential direction U, and so as to be immediately adjacent, in an axial direction A, to the rotor region that is to be machined. Here, the wheels 8 of the carriages 2 engage into, and are guided in, intermediate spaces 40 which are formed between provided sealing strips 39 and which extend in the circumferential direction U. The floating mounting of the wheels 8 allows displacement of the wheels 8 in an axial direction A such that they fit into the intermediate spaces 40. The track blocks 22 of the carriage 2 that receives the tool carrier 14 are positioned so as to engage into the groove 37 that is to be machined, in order to ensure exact guidance of said carriage 2. In a further step, the free ends of the lashing strap 3 are connected to one another by means of the tensioning device 4 and are subsequently tensioned until a predetermined tension force is attained, which can be read off on the measuring device 32. Furthermore, weights 23 can be placed into the frames 5 of those carriages 2 which are arranged opposite the carriage 2 comprising the tool carrier 14, in order to compensate for imbalances. The arrangement illustrated in FIG. 13 has now been produced.

[0053] To carry out the machining, the machining tool 15 is now activated so as to be driven in rotation. The axial and radial advancement of the machining tool 15 are performed manually by means of the corresponding advancing devices 17 and 18. The feed movement in the circumferential direction U is implemented manually. For this purpose, an operator may grip one of the handles 13 and pull the associated carriage 2 in the circumferential direction U. Alternatively, the operator may also implement the feed movement by means of one of the feed devices 26. For this purpose, the operator pushes the hand lever 30 of one of the lifting devices 31 downward in order to thus set the friction wheel 27 of the lifting device 31 down onto the rotor 35.

[0054] The operator subsequently actuates the handwheel 28 of the feed device 26 in order to drive the friction wheels 27 via the belt drive 29.

[0055] Although the invention has been illustrated and described in more detail on the basis of the preferred exemplary embodiment, the invention is not restricted by the disclosed examples, and a person skilled in the art may derive other variations from these without departing from the scope of protection of the invention.