MOBILE MACHINE TOOL AND METHOD FOR SEGMENTALLY MACHINING A COMPONENT

Abstract

A mobile machine tool for segmentally machining, in situ, a component, in particular a component of a turbine, which is rotatable about an axis of rotation. The machine tool has a main body, a support element which is held on the main body so as to be movable about a C-axis along a circular-arc-shaped guide path, and a tool module which is held on the support element and is designed to receive a tool. The tool module is located on the support element so as to be linearly movable. A method segmentally machines, in-situ, a component which is mounted in a stationary body so as to be rotatable about an axis of rotation.

Claims

1. A mobile machine tool for segmentally machining, in situ, a component which is rotatable about an axis of rotation, in particular a component of a turbine, comprising: a base body, on which fastening means are provided for releasably mounting the base body on a body which is stationary relative to the axis of rotation and which defines the axis of rotation, in particular on a turbine housing, a carrier element, which is held on the base body so as to be movable about a C axis along a circular-arc-shaped guide path, and a tool module, which is held on the carrier element and is designed to receive a tool, in particular a cutting tool, preferably a grinding wheel or a side milling cutter, wherein the tool module is arranged on the carrier element so as to be linearly adjustable transversely, in particular radially with respect to the C axis.

2. The machine tool as claimed in claim 1, wherein the circular-arc-shaped guide path extends over a center angle of at least 20° and/or at most 40° about the C axis.

3. The machine tool as claimed in claim 2, wherein the carrier element is held on the base body by a profile guide so as to be movable about the C axis.

4. The machine tool as claimed in claim 3, wherein the profile guide has a double profile, which is provided on the base body and engages positively in a corresponding mating profile provided on the carrier element and/or wherein the profile guide has a dovetail or a T-profile which engages positively in a corresponding mating contour on the carrier element, and/or wherein the profile guide has an arcuate guide with linear rolling bearing elements, preferably balls or rollers.

5. The machine tool as claimed in claim 4, further comprising: feed means for moving the carrier element relative to the base body.

6. The machine tool as claimed in claim 5, wherein the feed means comprises a toothed rack, which extends in an arc along or parallel to the circular-arc-shaped guide path, and a gearwheel, which is in engagement with the toothed rack.

7. The machine tool as claimed in claim 6, wherein the toothed rack is arranged on the base body and the gearwheel is mounted rotatably on the carrier element, wherein the gearwheel is in engagement with the toothed rack, preferably radially on the outside with respect to the C axis.

8. The machine tool as claimed in claim 6, wherein the feed means further comprise a drive unit, which is coupled to the gearwheel in order to drive the gearwheel and move the carrier element relative to the base body, wherein, in particular, the drive unit comprises a motor in the form of an electric motor and/or a hydraulic motor and/or a pneumatic motor and preferably a transmission coupled to the motor, preferably a planetary transmission.

9. The machine tool as claimed in claim 1, further comprising: a linear guide to guide the tool module radially with respect to the C axis relative to the carrier element.

10. The machine tool as claimed in claim 9, wherein the linear guide is designed as a recirculating ball guide or as a recirculating roller guide.

11. The machine tool as claimed in claim 9, wherein the linear guide comprises at least one, in particular two, profile rails, which is/are arranged on the carrier element and engages/engage positively in the tool module, in particular in an intermediate plate of the tool module, wherein, in particular, the profile rails have a dovetail or a T-profile and engage in a corresponding mating contour on the tool module.

12. The machine tool as claimed in claim 9, further comprising: adjusting means to move the tool module relative to the carrier element.

13. The machine tool as claimed in claim 12, wherein the adjusting means comprise a drive motor in the form of an electric motor and/or a hydraulic motor and/or a pneumatic motor and, in particular, a transmission, preferably a planetary transmission, wherein the drive motor is connected in a fixed manner to the carrier element, in particular screwed thereto, and is coupled to the tool module via a screw mechanism.

14. The machine tool as claimed in claim 13, wherein the screw mechanism is designed as a ball screw and comprises a ball screw shaft, which is coupled to the drive motor for conjoint rotation therewith, and has a ball screw nut, which is connected in a fixed manner to the tool module, in particular, is introduced into a bore formed therein, with a result that a rotational movement of the ball screw shaft is converted into a linear movement of the tool module relative to the carrier element.

15. The machine tool as claimed in claim 1, wherein the tool module comprises drive means for driving a tool mounted on the tool module in rotation about a tool axis, wherein, in particular, the drive means comprise an electric motor and/or a hydraulic motor and/or a pneumatic motor.

16. The machine tool as claimed in claim 1, wherein the tool module has a mount for a tool which can be driven in rotation about a tool axis, wherein the tool axis extends, in particular, parallel to the C axis, wherein, in particular, the mount comprises a mandrel, onto which a tool with a corresponding opening can be pushed, and securing means for fixing the tool on the mandrel, wherein, preferably, the securing means have a screw which is screwed into a threaded bore formed in the mandrel in order to fix a pushed-on tool.

17. The machine tool as claimed in claim 1, wherein the tool module further comprises suction means in order to be able to extract chips or other contaminants arising during machining, and/or wherein the tool module comprises a protective cover for protecting the surroundings from flying fragments during machining, and/or wherein the fastening means of the base body have bores, in particular slotted holes, for screwing the base body to a stationary body, and/or wherein the base body has a bearing surface for resting, in particular resting flat, against a stationary body, and/or wherein the base body has a base plate, on which a bearing surface is formed for resting flat against a stationary body, and comprises a guide plate, which projects, in particular perpendicularly, from the base plate, on which the tool module is held so as to be movable and which, in particular, extends parallel to a plane spanned by the circular arc, wherein, in particular, support means are provided on the guide plate, preferably in an outer region of the guide plate remote from the base plate, in order to support the base body perpendicularly to the plane spanned by the circular arc.

18. A method for segmentally machining, in situ, a component mounted so as to be rotatable about an axis of rotation in a stationary body, comprising: a) providing a machine tool which is designed to machine the component over a circumferential segment, and mounting the machine tool on the stationary body; b) machining a first circumferential segment of the component using the machine tool; c) rotating the component about its axis of rotation by a predetermined angle; d) machining a further circumferential segment of the component using the machine tool; e) repeating steps c) and d) until the component has been machined over its entire circumference.

19. A method for segmentally machining, in situ, a component mounted so as to be rotatable about an axis of rotation in a stationary body, comprising: a) providing a machine tool as claimed in claim 1, which is designed to machine the component over a circumferential segment, and mounting the machine tool on the stationary body; b) machining a first circumferential segment of the component using the machine tool; c) rotating the component about its axis of rotation by a predetermined angle; d) machining a further circumferential segment of the component using the machine tool (1); e) repeating steps c) and d) until the component has been machined over its entire circumference wherein, preferably, the C axis of the machine tool coincides with the axis of rotation of the component.

20. The method as claimed in claim 19, wherein the component to be machined is a component of a turbine, in particular a component stacked on a central shaft of the turbine, and the stationary body is a turbine housing or a part thereof.

21. The method as claimed in claim 20, wherein during normal operation, the component of a turbine is connected in a fixed manner to the housing and is decoupled from the housing before machining and is coupled to a rotor or to the central shaft of the turbine for conjoint rotation therewith, and/or wherein the stationary body is a housing half of the turbine housing and the machine tool is mounted on a parting plane that rests against the other housing half during operation.

22. The method as claimed in claim 19, wherein during machining, an axial, annularly encircling projection formed on the component is shortened, wherein, in particular, an annularly encircling section is cut off from the component, wherein, preferably, the annularly encircling section is cut off from the component by a grinding wheel which engages radially from the outside or by a side milling cutter which engages radially from the outside and/or, after the cutting off of the annularly encircling section, the latter is broken down into smaller pieces.

23. The method as claimed in claim 19, wherein the component is locked during the machining of a circumferential segment in order to prevent unintentional rotation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Further features and advantages of the present invention will become clear from the following description of a mobile machine tool according to one embodiment of the present invention with reference to the appended drawing. In the drawing:

[0044] FIG. 1 shows a front view of a mobile machine tool according to one embodiment of the present invention during the machining of a component of a turbine;

[0045] FIG. 2 shows a perspective view of the arrangement from FIG. 1;

[0046] FIG. 3 shows a detailed perspective view of the arrangement from FIG. 1;

[0047] FIG. 4 shows a detail front view of the arrangement from FIG. 1;

[0048] FIG. 5 shows a detail plan view of the arrangement from FIG. 1.

DETAILED DESCRIPTION OF INVENTION

[0049] FIGS. 1 to 5 show a gas turbine arrangement with a mobile machine tool 1 according to the present invention attached thereto.

[0050] The turbine arrangement comprises a stationary turbine housing, which has an upper housing half (not illustrated and removed) and a lower housing half 3. A central shaft 4 is mounted so as to be rotatable about an axis of rotation Z in the turbine housing 2. This shaft carries a plurality of components of the turbine, in particular rotor wheels, which are stacked one behind the other in the direction of the axis of rotation Z and are connected to the shaft 4 for conjoint rotation therewith. Arranged in the stack sequence is a compressor outlet diffuser 5, which does not rotate with the shaft 4 during operation of the turbine but is secured on the turbine housing 2.

[0051] The compressor outlet diffuser 5 has an axial projection 6, which runs around in the form of a ring and, during operation of the turbine, faces a component (not illustrated) which is coupled for conjoint rotation to the shaft 4, forming a defined gap. In the present case, this axial projection 6 of the compressor outlet diffuser 5 is to be shortened all the way around in order to increase the gap width with respect to the adjacent component, which corotates during operation.

[0052] The mobile machine tool 1 is used for this purpose. The latter has a base body 7, which has a base plate 8 and a guide plate 9, which projects perpendicularly from the latter. Formed on the base plate 8 is a bearing surface to enable it to be placed on a flat surface of the lower housing half 3 of the turbine housing 2. Furthermore, fastening means are provided on the base plate 8 in order to releasably mount the base body 7 on the lower housing half 3. In the present case, the fastening means of the base body 7 comprise slotted holes 10, which are formed in the base plate 8 and via which the base body 7 is screwed to the lower housing half 3 of the turbine housing 2 (screws not illustrated).

[0053] In order to achieve particularly stable and secure fastening of the base body 7 to the turbine housing 2, support means are also provided in the region of the guide plate 9 remote from the base plate 8. These comprise a U-shaped fastening bracket 11, which is held at an axial distance from the guide plate 9 by means of a screw 12 and engages in a positive and/or non-positive manner around a further component 13, in particular a component connected nonrotatably to the turbine housing 2.

[0054] A carrier element 14 is held on the guide plate 9 of the base body 7 so as to be movable about a C axis along a circular-arc-shaped guide path, which in the present case coincides with the axis of rotation Z of the shaft 4. The circular-arc-shaped guide path extends over a center angle with respect to the C axis of approximately 30°. In this case, the guide plate 9 is aligned in such a way that it extends parallel to the plane spanned by the circular-arc-shaped guide path.

[0055] The carrier element 14 is held on the base body 7 by means of a profile guide so as to be movable about the C axis. Specifically, the profile guide has a double profile 15, which is provided on the base body and is formed in one piece with the latter in the present case, and which engages positively in a corresponding mating profile 16 provided on the carrier element 14. The two profiles of the double profile 15 have a rectangular cross section.

[0056] In order to be able to position and move the carrier element 14 relative to the base body 7, feed means are also provided. These comprise a toothed rack 17, which extends parallel to the circular-arc-shaped guide path and is arranged on the base body 7, and a gearwheel 18, which is mounted rotatably on the carrier element 14. In this case, the gearwheel 18 is in engagement with the toothed rack 17 radially on the outside with respect to the C axis.

[0057] The feed means further comprise a drive unit, which is held on the carrier element 14 and is coupled to the gearwheel 18 in order to drive the gearwheel 18 and move the carrier element 14 relative to the base body 7. Specifically, the drive unit in the present case has a motor in the form of an electric motor 19, which in the present case is screwed to the carrier element 14.

[0058] In addition, the mobile machine tool 1 has a tool module 20, which is arranged on the carrier element 14 so as to be linearly adjustable radially with respect to the C axis and is designed to receive a tool, in the present case a grinding wheel 21. In the present case, a linear guide is provided in order to guide the tool module 20 radially with respect to the C axis relative to the carrier element 14. This comprises two profile rails 22, which are arranged on the carrier element 14 and engage positively in an intermediate plate 23 of the tool module 20.

[0059] In order to move the tool module 20 relative to the carrier element 14, adjusting means are furthermore provided, which in the present case comprise a drive motor in the form of an electric motor. The electric motor 24 is screwed to the carrier element 14 and coupled to the tool module 20 via a screw mechanism. The screw mechanism is embodied as a ball screw and comprises a ball screw shaft 25, which is coupled to the electric motor 24 for conjoint rotation therewith. Furthermore, the screw mechanism comprises a ball screw nut 26, which is connected in a fixed manner to the intermediate plate 23 of the tool module 20 and is introduced into a bore formed in the latter. In this way, a rotational movement of the ball screw shaft 25 is converted into a linear movement of the tool module 20 relative to the carrier element 14.

[0060] In order to drive the grinding wheel 21, the tool module 20 has drive means. In the present case, these likewise comprise an electric motor 27, which is connected in a fixed manner to the intermediate plate 23 of the tool module 20.

[0061] The tool module 20 has a mount 28 for the grinding wheel 21, which is rotatable about a tool axis W and extends parallel to the C axis and to the axis of rotation Z. In a specific embodiment, the mount 28 comprises a mandrel 29, onto which the grinding wheel 21 is pushed, and securing means in the form of a screw 30 in order to fix the tool on the mandrel 29. For this purpose, the screw 30 is screwed into a threaded bore 31 formed in the mandrel.

[0062] In order to protect the surroundings from flying fragments during machining, the tool module 20 has a protective cover 32, which covers a part of the grinding wheel 21 in the axial direction.

[0063] If, as envisaged according to the invention, the axial projection 6 of the compressor outlet diffuser 5 of the turbine arrangement is to be shortened all the way around, the upper housing half (not illustrated) of the turbine housing 2 is removed in a first step. Subsequently, the mobile machine tool 1 is mounted on the lower housing half 3 of the turbine housing 2, specifically on the parting plane 33, which rests against the upper housing half during operation. For this purpose, the base body 7 of the mobile machine tool 1 is screwed to the lower housing half 3 via the slotted holes 10.

[0064] Since the compressor outlet diffuser 5 is connected in a fixed manner to the housing during operation but is part of the stacking sequence, the nonrotatable coupling to the turbine housing 2 is released and the compressor outlet diffuser 5 is temporarily coupled rotationally to the shaft 4 for machining purposes, for example via a connection to an adjacent component connected to the shaft 4 for conjoint rotation therewith.

[0065] After the mobile machine tool 1 has been mounted on the lower housing half 3 and the compressor outlet diffuser 5 has been coupled to the shaft 4 for conjoint rotation therewith, the first circumferential segment of the axial projection 6 can now be machined. For this purpose, after the shaft 4 has been locked, the rotating grinding wheel 21 is moved radially inward with respect to the C axis by moving the tool module 20 forward along the linear guide relative to the carrier element 14. When the grinding wheel 21 is in a position such as that illustrated, for example, in FIG. 1, in which the grinding wheel completely penetrates the axial projection 6, the carrier element 14 with the tool module 20 held thereon is moved along the circular-arc-shaped guide path about the C axis. As a result, the axial projection 6 is machined over the circumferential segment defined by the circular-arc-shaped guide path. When the carrier element 14 reaches the upper end (illustrated in FIG. 1) of the circular-arc-shaped guide path relative to the base body 7 of the mobile machine tool 1, the grinding wheel 21 can be moved out of the axial projection 6 of the compressor outlet diffuser 5 and the carrier element 14 can be moved into its lower edge position relative to the base body 7.

[0066] Now, the compressor outlet diffuser 5 can be rotated about its axis of rotation Z by a predetermined angle, thus enabling the next circumferential segment of the axial projection 6 to be machined in the same way. This procedure is then repeated until the axial projection 6 has been machined over its entire circumference.

[0067] After machining over the entire circumference, there is a severed annularly encircling section, which is now broken down manually into smaller pieces to enable it to be removed from the shaft 4. Thus, by means of the method according to the invention, using the mobile machine tool 1 according to the present invention, annularly encircling machining, in particular shortening of the axial projection 6, is made possible without the need for laborious disassembly and machining on a separate system.

[0068] Although the invention has been illustrated and described more specifically in detail by means of the preferred illustrative embodiment, the invention is not restricted by the examples disclosed, and other variations can be derived therefrom by a person skilled in the art without exceeding the scope of protection of the invention.