The invention relates to a method for manufacturing a housing of a turbomachine as well as a turbomachine housing.
Turbomachine housings, for example, engine housings of aircraft engines are usually provided with different housing elements. Examples of such housing elements are bosses, flanges for through-guides and borescopes, rails, local thickened areas and struts, in order to locally improve the strength properties of the housing. These housing elements are manufactured by machining a housing blank.
Viewed as a disadvantage of fabrication by machining is the circumstance that comparatively large machining allowances are required and a correspondingly high expenditure for machining is necessary.
The object of the present invention is to specify a method which makes possible a more rapid and more cost-effective manufacture of a housing of a turbomachine. Another object of the invention is to specify a housing that can be manufactured in a correspondingly more rapid and more cost-effective manner.
These objects are achieved according to the invention by a method and housing of the present invention. Advantageous embodiments with appropriate enhancements of the invention are set forth in detail below, wherein advantageous configurations of the method are to be viewed as advantageous embodiments of the housing, and vice versa.
A first aspect of the invention relates to a method for manufacturing a housing of a turbomachine, particularly of a gas turbine. In this case, according to the invention, at least the following steps are conducted: providing a housing blank, manufacturing a housing element, producing an assembly opening corresponding to the housing element in the housing blank, arranging the housing element in the assembly opening, and joining the housing element to the housing blank by means of a welding method. Therefore, unlike the prior art, it is no longer necessary to manufacture the housing blank with a large machining allowance and to process by machining in complex manner. This makes possible considerable savings in cost and time, as well as minimizing the costs of the blank. Additionally, it is possible to manufacture the one or more housing elements independently of fabrication sequences on the housing blank. In the simplest embodiment of the invention, the housing produced in this way no longer requires additional mechanical post-processing steps; rather, at most it requires a heat treatment. In particular, separating steps such as cutting or the like are usually no longer necessary. The housing element can be welded basically to the housing blank with or without a welding filler. The use of a welding filler generally permits greater tolerances.
In an advantageous embodiment of the invention, it is provided that a housing blank with an at least substantially rotationally symmetrical, particularly cylindrical or conical geometry is provided. As used throughout herein, the expression “substantially rotationally symmetrical” in general means the shape of a rotationally symmetrical body designed around an axis of rotation, wherein the axis of rotation is preferably disposed coaxially with an axis of rotation of a rotor of an assigned turbomachine. Correspondingly, “substantially cylindrical” in general means having the shape of a cylinder, either with or without a specific contour. Analogously, “substantially conical” in general means having the shape of a cone or taper, either with or without a specific contour. In this case, it can also be provided that the housing blank has several segments, each of which are designed at least substantially cylindrical or conical. The housing blank is usually hollow on the inside.
Additional advantages result by manufacturing the housing element by means of at least one method from the group: machining, electrochemical machining (ECM), and additive manufacturing methods, in particular laser beam melting and/or electron beam melting. The at least one housing element can be manufactured particularly rapidly and economically as a function of its respective geometry and functionality.
Additional advantages result if the housing element is manufactured on and/or with a platform being arranged in the assembly opening, whereby the platform preferably has a wall thickness corresponding to the wall thickness of the housing blank. The housing element can be joined particularly rapidly, simply and precisely to the housing blank thereby, since the platform already has the geometry adapting to the assembly opening, and preferably also has a wall thickness corresponding to the housing blank. In addition to this, it is possible to manufacture different housing elements on and/or with standardized or individually adapted platform types. This permits the introduction of correspondingly standardized assembly openings into the housing blank, whereby the assembly openings, for example, can be adapted to a specific housing element functionality in order to ensure a secure assembly that cannot be changed.
In another advantageous embodiment of the invention, an assembly opening with an at least substantially circular or oval or polygonal, in particular rectangular, geometry is produced in the housing blank. In other words, it is provided that one or more assembly openings are produced with a geometry that is as simple as possible. This also makes possible considerable advantages relative to time and cost, both in the production of the assembly opening(s) as well as in the arrangement and attachment of the one or more housing elements. In addition to this, an unnecessary weakening of the housing blank is avoided. In the case of an angular geometry, it can be basically provided that one, several, or all corners are or will be rounded.
In another advantageous embodiment of the invention, the housing element is aligned relative to the assembly opening when it is arranged by means of at least one centering element. This ensures a failproof arrangement (failproof design) of the housing element. The centering element can be, for example, a centering lip that is formed on the housing element and/or the assembly opening, and this lip cooperates with a corresponding groove, recess, notch, or the like when the housing element is arranged, so that the housing element can only be inserted into the assembly opening in the correct, three-dimensional alignment.
In another advantageous embodiment of the invention, it is provided that the assembly opening is produced by means of at least one separating method, in particular, from the group: eroding, milling and laser beam cutting. This permits introducing the assembly opening(s) into the housing blank rapidly, precisely, and correctly as required.
Additional advantages result by heating the housing blank prior to arranging the housing element in the assembly opening, and subsequently shrink fitting the housing element into the assembly opening. In this way, a force-fit connection is produced, whereby the housing element is particularly simply joined and can resist especially high mechanical and thermal loads.
A particularly rapid and precise joining of the housing element with minimum input of heat into the housing blank is achieved in another embodiment of the invention by attaching the housing element to the housing blank by means of at least one welding method from the group: electron beam welding and laser beam welding.
In order to be able to optimally adapt the housing to its respective purpose of application, in another embodiment of the invention, it has proven to be advantageous if the housing element is manufactured with at least one structural element from the group: flange, rail, boss, local thickened area, shoulder, through-guide, and/or strut.
In another advantageous embodiment of the invention, it is provided that the housing blank is thermally expanded, after which at least one rail is arranged in the housing blank and is shrunk fit, and/or that a flange is thermally expanded, after which the flange is arranged on the housing blank and is shrunk fit on the housing blank. Both rails (inner flanges) as well as outer flanges can be joined thereby in a force fit to the housing blank, whereby they can be loaded particularly greatly mechanically and thermally.
In another advantageous embodiment of the invention, at least one stop piece is manufactured on the housing blank, by means of which the rail and/or the flange is/are aligned relative to the housing blank. This permits a particularly precise and failproof alignment of the rail and/or of the flange on/in the housing blank.
In another embodiment of the invention, it is provided that the stop piece is manufactured by means of a separating method, in particular by milling, and/or is joined to the housing blank by a joining method, in particular by welding and/or adhesive bonding. This permits forming or fastening the stop optimally as a function of the respective structural specificities. In the case of a separating method, a corresponding machining allowance of the housing blank is necessary, so that the stop piece can be manufactured, for example, by peripheral or local milling technique. It is likewise possible to join local stop pieces or seating elements to the housing blank by a joining technique. In particular, cohesive methods such as spot welding, adhesive bonding, etc. are advantageous as joining methods.
A particularly reliable connection is achieved in another embodiment of the invention by welding the rail and/or the flange to the housing blank, in particular by means of a peripheral weld and/or a fillet weld and/or an I-butt and/or an I-seam.
A second aspect of the invention relates to a turbomachine housing, particularly a gas turbine, wherein the housing can be manufactured in a more rapid and cost-effective manner, in that it comprises a housing blank, on or in which a housing element is fastened in a corresponding assembly opening in the housing blank and is welded to the housing blank. Therefore, unlike the prior art, it is provided that the housing element is not produced directly from the housing blank, but is first manufactured separately from the housing blank and after this is arranged in an assembly opening produced in the housing blank and joined to the housing blank by welding. This makes possible considerable savings in cost and time, as well as minimizing the costs of the blank, since the one or more housing elements can be manufactured on or in the housing blank independently from the fabrication sequence. In the simplest embodiment of the invention, the housing produced in this way no longer requires additional mechanical post-processing steps; rather, at most it requires a heat treatment. In particular, separating steps such as cutting or the like are usually no longer necessary. Preferably, the housing can be obtained and/or is obtained by means of a method according to the first aspect of the invention, wherein advantageous embodiments of the first aspect of the invention are to be viewed as advantageous embodiments of the second aspect of the invention, and vice versa.
Further features of the invention result from the claims and the examples of embodiment. The features and combinations of features named above in the description, as well as the features and combinations of features named in the examples of embodiment below and/or shown alone can be used not only in the combination indicated in each case, but also in other combinations or uniquely, without departing from the scope of the invention. Thus, embodiments of the invention that are not explicitly shown and explained in the embodiment examples, but proceed from the explained embodiments and can be produced by separate combination of features, are also to be viewed as comprised and disclosed. Embodiments and combination of features that thus do not have all features of an originally formulated independent claim are also to be viewed as disclosed. Herein:
It is recognized that the housing blank 10 is formed at least substantially rotationally symmetrical or cylindrical. An assembly opening 12 that corresponds to a housing element 14, which is shown schematically in
In addition, the housing element 14 comprises local design features or structural elements 18, which are formed on the platform 16. Structural elements 18 can comprise, for example, flanges, local thickened areas, shoulders, through-guides, and/or struts, in order to provide the housing blank 10 with specific properties, connection points, or the like. The housing element 14 thus can be manufactured separately, independently from the fabrication of the housing blank 10, for example, by machining, ECM, or by additive manufacture. The platform 16 can be provided as the base for building up the structural element 18 or it can be manufactured together with the structural element 18, depending on the manufacturing method. In the case of an additive manufacture, laser beam melting or electron beam melting is preferably used, in order realize a so-called near net shape geometry, i.e., a geometry that is close to the final contours and requires no additional processing.
ΔT=ΔD/(α*D) (I)
in which
ΔT: temperature increase
α: thermal expansion coefficient
D: diameter of the housing blank 10
ΔD: difference in the diameters of housing blank 10 and rail 22.
If the housing blank 10 and the rail 22, for example, are composed of the material IN718 with α≈1.2*10−5 K−1, for D=1 m and ΔD=5/10 mm, a temperature increase ΔT≈40 K is necessary. It is generally preferred if the rail 22 is composed of a highly heat-resistant material, since high temperatures occur in this region during the operation of the finished turbomachine. The use of a highly heat-resistant material thus particularly prevents the occurrence of cracks and other wear phenomena (fretting). In addition, it can be provided that the rail 22 and the housing blank 10 have mutually corresponding centering elements (e.g., a centering lip 28) in order to ensure a correct three-dimensional arrangement relative to one another (“failproof design”). Several rails 22 can be manufactured by repeatedly applying the above-described procedure in one direction (i.e., from “bottom to top” or from “top to bottom”).
Number | Date | Country | Kind |
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10 2016 204 660.8 | Mar 2016 | DE | national |