DE102017200123A1 - mounting assembly - Google Patents

Abstract

The invention relates to a fastening arrangement (5) for fastening components to a wall (1) of a tower of a wind power plant, wherein the fastening arrangement (5) has a fastening element (2) and a brazing body (4), wherein the fastening element is secured by means of the brazing body (4 ) is firmly connected to the wall (1). The solder body (4) comprises a fillet weld. Furthermore, the invention relates to a method for producing the fastening arrangement (5).

Description

The invention relates to a fastening arrangement for fastening components to a wall of a tower of a wind power plant and to a method for producing a fastening arrangement.

Swinging stressed welded steel structures are particularly susceptible to fatigue due to the notch effect of welds and welded attachments as well as due to the process-related residual stresses in the welds.

Wind turbines are particularly highly loaded constructions in terms of cyclic loading. This is mainly due to natural frequencies of the rotor blades and the tower, a wind load and the rotor blade passage on the tower itself. As a result, such constructions up to 10 ⁹ load changes throughout the Operating life to endure and must be designed for such stress.

In addition to gondola including rotor blades and tower foundation, the tower, which is often built as a tubular steel tower design, represents a regulatory factor in the design of the total wind energy plant.

In order to construct stable towers, first load stress and extreme loads are determined in load simulations on the basis of which the tower is designed. For the fatigue analysis, the notion of notch effect plays a central role. As a notch one calls all cross-sectional transitions and form disturbances in the tower wall. In the vicinity of notches, a stress distribution deviates from that of the undisturbed component. This phenomenon is called the notch effect.

In a notch class, notches with the same or similar notch effect are summarized to simplify the calculation. For example, according to the European standard code (EN 1993, EN 1090), the weld bushings have a score of 80. This means that the component designed for this purpose is operationally stable for a maximum vibration stress width of 80 N / mm ² . That is, normal stresses in the tower wall can fluctuate for two million cycles with an amplitude of 40 N / mm ² , without causing failure. For a completely scoring-free tower wall, eg made of steel, a maximum notch class of 160 can usually be assumed.

Wind energy plants in steel segment construction usually have three welding details: on the one hand the longitudinal seams with notch class 125, the round seams (cross seams as butt welds for connecting the pipe segments) with notch class 90 and so-called welding bushes with notch class 80. The welding bushes are thus compared to the other welding details a weak spot.

The welding bushes allow the inclusion of tower installations such as crampons, ladders and cable management, and the attachment of the tower internals on the turn wall. In current wind turbines, well over a hundred welded sockets can be used.

The most commonly used method of joining the weld bushings to the tower inner wall is gas metal arc welding (MIG / MAG welding). In this case, the socket is welded by means of a fillet weld to the tower inner wall.

So is from the publication WO 2010/058037 A2 an attachment for fixing attachments to a metallic tower inner wall known, which is provided for welding to the inner door wall.

Advantageous are the cost-effective, rapid and simple assembly by the method and the versatile consideration of the application in the regulations for design. By melting the base material of the tower inner wall, however, only a comparatively low notch class can be achieved, and it must be used to compensate with correspondingly large material thicknesses.

The cause of the negative effect of the welding bushes is on the one hand in an unfavorable influence of the tower wall by the thermal action of the welding process. This can cause hardening, softening, internal irregularities and unfavorable welding residual stress states, all of which lead to a reduced fatigue strength. On the other hand, geometrical notch effects result from force deflections and deformation impediments due to such welded attachments.

Due to the relatively low notch class 80 of the welding bushings, the tower wall must be made thicker, which leads to a higher material usage and also prevents a higher construction in the sense of exploiting safe wind areas. Last but not least, such weld bushes lead to a high degree of notch sharpness and the associated significant reduction of sustainable vibrations overall lower life of wind turbines.

For a generic wind turbine (120 m hub height, 3 MW power), tower constructions with notch class 90 can save between 5 and 7 tons of steel per tower or class 112 between 15 and 23 tons of steel compared to class 80.

It would therefore be desirable to reduce the notch effect of the weld bushes or to increase the notch class.

In the publications DE 20 2012 009 889 U1 and EP 2 078 850 A2 It is proposed to attach components by gluing on the tower wall. A disadvantage is the flammability and often insufficient aging resistance of the adhesives to be used.

In the publications DE 20 2014 104 673 U1 . EP 2 574 779 A1 and EP 2 574 780 A1 It is proposed to fasten holding elements in holes in the tower wall.

In the publication EP 2 187 049 A2 it is proposed to shoot a bolt in the tower wall.

The attachment of attachments and bushings by means of magnetic holding force is in the document WO 03/067038 A1 described.

The publication DE 20 2016 101425 U1 describes the joining of add-on elements within a tower by means of a brazing process. In this case, a solder is to flow with the aid of a flux into a defined gap by capillary action between the bushing and the tower wall.

The invention has for its object to provide an arrangement for mounting components on a wall of a tower of a wind turbine, which avoids the disadvantages of the prior art. In addition, it is an object of the invention to provide a method for producing such a fastening arrangement.

The object is achieved by a fastening arrangement according to the main claim and a method according to the independent claim. Further developments are defined in the dependent claims and the exemplary embodiments and will be explained in more detail in the following description.

The fastening arrangement for fastening components to a wall of a tower of a wind power plant has a fastening element and a brazing body, wherein the fastening element is firmly connected to the wall by means of the brazing body or a soldering seam. Next, the solder body is formed as a fillet weld.

With a fillet weld, a reliable connection between the fastener and the wall can be created. As a result of the solder body, the wall of the tower is thermally stressed to a much lesser extent during the production of the fastening arrangement than in the case of a welded connection. The solder body forms a material connection between the fastening element and the wall, wherein the cohesive connection guarantees a sufficient strength of the component, without producing the negative effects of notches of a weld.

The fillet weld can be a curved seam, a flat seam or a hollow seam.

It can be provided that the fastening element and the wall at least partially abut each other. The fastener may therefore at least partially touch the wall. A defined gap between the fastener and the wall, as it is needed in the brazing process, but is therefore not necessary. In particular, in the case of a cylindrical tower wall of a wind power plant, the attachment of the fastening element to the wall can thereby be simplified.

The solder body may extend at least partially outside around an outer wall of the fastener. The solder body can e.g. be formed annular or U-shaped.

It can be provided that the wall has a first surface and the fastening element has a second surface, wherein said surfaces are substantially perpendicular to each other. The solder body may form a solder bridge between the first surface and the second surface.

In a development, the solder body is produced by arc joining, in particular arc soldering. In one embodiment, the solder body is flux-free. Fluxes are often used in soldering or brazing and pose a health hazard. On the other hand, when brazing under a protective gas atmosphere, e.g. Arc brazing, usually no flux required.

In one embodiment, the fastening element is cylindrical or cuboid. The fastener is designed for example as a socket, flag plate or bolt. The fastening element can be fastened with an end face on the wall. In addition, the fastener may have a through hole extending from said Front side extends to one of said end face opposite end side. Furthermore, the fastening element can have an internal thread and / or an external thread. The through hole can be configured in particular as a through bore with internal thread. As a result, components can be easily connected to the fastener or attached to the fastener.

In one embodiment, the solder body is formed by a copper-based solder, a nickel-based solder, a cobalt-based solder or an iron-based solder. The solder and / or the solder body in this case may have a melting temperature of at least 900 ° C and / or at most 1200 ° C. For example, CuSi3 has a melting range of 910 - 1025 ° C, while CuAl8 has a melting range of 1030 - 1040 ° C. Typically, steel used for the interior wall of the wind turbine has a melting temperature of about 1400 ° C or even more. Due to the envisaged melting temperature of the solder, the solder can be melted without the wall being damaged. Typically, the solder body and the wall are thus made of different materials.

It can be provided that the solder body has a lower modulus of elasticity (modulus of elasticity) than the wall and / or the fastening element. This results in a reduced deformation obstruction and thus stress spikes can be reduced. The modulus of elasticity of steel typically used for the construction of the wall and / or fastener is typically greater than 2 × 10 ⁵ N / mm ² , eg 2.1 × 10 ⁵ N / mm ² . On the other hand, the modulus of elasticity of the solder body may be up to 1.4 × 10 ⁵ N / mm ² , in particular, the elastic modulus of the solder body may be smaller than 1.3 × 10 ⁵ N / mm ² . For example, the modulus of elasticity of the solder body is 1.2 × 10 ⁵ N / mm ² .

In one embodiment, the solder body comprises a single layer or multiple layers of a solder or different solders. For the connection of the fastener to the wall, the fastener assembly may also comprise a plurality of solder bodies, e.g. 2, 3 or even more.

The fastening arrangement can be assigned to a notch class (see above definition) of at least 90, in particular at least 100 and / or at most 130 or 120.

The fastener may e.g. be connected to a tower inner wall or a tower outer wall. The components that are attached to the wall of the tower of the wind turbine, in particular crampons, ladders and cable management can be. Other components are also conceivable. Typically, a wind turbine includes a tower with a tower wall. The wind turbine may have the above-mentioned attachment arrangement or a plurality of such attachment arrangements.

• - Anordnen eines Befestigungselements an einer Wand eines Turms einer Windkraftanlage;
• - Schmelzen des Lots, wobei zumindest die Wand (1) in einem festen Aggregatszustand bleibt;
• - Bilden eines Lotkörpers mit einer Kehlnaht; und
• - Verbinden des Befestigungselements mit der Wand mittels mit der Kehlnaht des Lotkörpers.

The invention also provides a method for producing a fastening arrangement. The method comprises the following steps:

• - placing a fastener on a wall of a tower of a wind turbine;
• - Melting of the solder, wherein at least the wall (1) remains in a solid state of aggregation;
• - forming a solder body with a fillet weld; and
• - Connecting the fastener to the wall by means of the fillet weld of the solder body.

When melting the solder so it should be noted that only the solder melts; the wall and preferably also the fastening element should remain in a solid state of aggregation.

Preferably, the solder is applied during melting on the fastener and / or on the wall of the tower. Alternatively, the solder can also be arranged on the fastening element and / or on the wall before melting. In a further development, the steps of melting the solder and / or producing the solder joint take place with supply of an inert gas or in an at least partial vacuum.

Suitable shielding gases depend on the process parameters. For example, pure argon or pure helium or argon or helium-rich mixed gases can be used as protective gases. The partial vacuum can be, for example, a rough vacuum with a pressure of 1 mbar to 300 mbar or a fine vacuum with a pressure of 10 ^-3 mbar to 1 mbar.

By the vacuum or the protective gas, oxidation of the connection partners can be prevented, whereby a stronger solder joint can be produced. At the same time, the material surface can be sufficiently activated by the arc effect. This can also be dispensed with any flux.

In one embodiment, the solder is melted by means of an arc.

For example, the fastener by means of arc soldering to the wall get connected. Arc brazing in the context of the present invention is a fusion joining process, in which the connection between materials is made via a non-related filler material. Arc brazing is defined, for example, in the DVS Merkblatt (German Association for Welding Technology) 0936. The compound is typically formed by interfacial reactions, including wetting, spreading, capillary behavior, and diffusion processes. Arc brazing is usually a joint brazing process, in contrast to the otherwise common Spaltlötverfahren. While in gap brazing a defined gap is filled mainly by a capillary filling pressure with solder, in joint brazing a joint can be filled mainly by gravity with solder. The energy transfer for melting the solder takes place by means of electrical gas discharge (arc) under inert gas. Due to the relatively low melting temperatures of the brazing materials connections with low damage and low thermal stress of the base materials can be achieved.

For example, the following arc-brazing techniques can be used with the present invention: metal inert gas (MSG), tungsten inert gas (WSG) and plasma brazing. Further details of arc welding and arc brazing can be seen by those skilled in the art.

Alternatively, for the solder melting step, a welder, e.g. a metal inert gas welder (MSG welder) can be used.

Said method for producing a fastening arrangement is in particular suitable for producing a fastening arrangement described above.

It should be emphasized at this point that features which have been mentioned only with regard to the fastening arrangement can also be claimed for the said method and vice versa.

The mounting arrangement and the method for producing the mounting arrangement allow for simple feasibility a significant reduction of the notch sharpness of the fasteners in wind turbines. As a result, on the one hand the service life can be increased, but also large masses of tower material can be saved. Furthermore, there are constructive and dimensionally new possibilities for the design of the entire wind turbine. Due to an increased notch class, significantly higher hub heights can be generated and towers with reduced wall thickness can be realized. In addition, in the context of tower manufacturing, cost advantages may also result from reduced throughput times and test times. Also maintenance, repair and / or service can be simplified by the mounting arrangement or the method for producing the same, and / or costs can be saved.

It should also be noted that the reduced energy input during soldering, in comparison to welding, prevents the burn-up of coatings around the joint. This is particularly important for smaller wall thicknesses, if the opposite side of the sheet is already coated. In addition, the smoke load due to soldering may be less than that of a welding process and may be less harmful to health due to the low toxicity of copper in the human body or the large recording tolerance.

• 1 einen Teil eines Querschnitts einer Turmwand einer Windkraftanlage,
• 2 eine Wöhler-Kurve aufgeschweißter Buchsen sowie aufgelöteter Buchsen,
• 3 Kehlnähte im Querschliff einer Schweißung (links) und einer Lötung (rechts) einer Befestigungsanordnung und
• 4 eine Aufsicht und einen Querschnitt eines für die Aufnahme der Wöhler-Kurve der 2 untersuchten Probenkörpers .

Further advantages and features of the invention will become apparent from the following description in which the invention is explained in more detail with reference to accompanying figures. In the figures shows

• 1 a part of a cross section of a tower wall of a wind turbine,
• 2 a Wöhler curve of welded sockets and soldered sockets,
• 3 Fillet welds in the cross section of a weld (left) and a soldering (right) of a mounting arrangement and
• 4 a top view and a cross-section of a for recording the Wöhler curve of 2 investigated sample body.

In the figures, recurring features are given the same reference numerals.

1 shows a part of a cross section of a tower wall 1 , The tower wall 1 is part of a wind turbine not shown and is built in steel segment construction. For the realization of the invention, it does not matter how the wind turbine or the tower of the wind turbine are designed in detail. Thus, the wind turbine may be a vertical runner or a horizontal runner, and a hub height may be, for example, between 20 and 200 m. The tower wall 1 is made in particular of a metal, usually steel for the construction of the tower wall 1 is selected.

In the figure is a mounting arrangement 5 for attaching components to the tower wall 1 shown. The mounting arrangement 5 has a fastener 2 on, with the tower wall 1 is firmly connected by means of a solder body 4. in this connection can the fastener 2 be attached to an outside or on an inside of the tower wall; in the illustrated embodiment, the fastener 2 on an inside of the tower wall 1 (Tower wall) attached. The fastener 2 touches the tower wall 1 partially, leaving the tower wall 1 and the fastener 2 partially abut each other.

The fastener 2 is executed in the embodiment shown as a cylindrical socket. The socket 2 is with a front side 8th on the wall 1 attached and includes a through hole 3 extending from the mentioned end face 8th up to one of said end face 8th opposite end face 7 extends. The hole 3 has an internal thread 6 on. Alternatively or additionally, an external thread on an outer side of the socket 2 be provided. Using the internal thread 6 and / or the external thread components can be attached to the fastener. These components can be designed differently; For example, ladders, platforms and cable guides are conceivable. Typically, a wind turbine has well over a hundred such mounting arrangements 5 on to the mentioned components on the turn wall 1 to fix.

The solder body 4 also has a fillet weld and forms a solder bridge between a surface of the fastener 2 and a surface of the wall 1, the surfaces being aligned perpendicular to each other. The solder body 4 thus forms a material connection between the socket 2 and the tower wall 1 , In the embodiment shown, the solder body 4 annular and circumferentially around the cylindrical bush 2 trained around.

The solder body 4 is manufactured in an arc brazing process. Because of the solder body 4 produced by arc soldering, can usually be dispensed with a flux. As a result, the solder body 4 without flux. For a definition of arc brazing, reference is made to the above description.

The solder body 4 may for example be formed by a Kupferbasislot, a Nickelbasislot, a cobalt base solder or a Eisenbasislot. The socket 2 and the wall 1 are made of a metal, wherein steel was selected in the illustrated embodiment.

Typically, the solder body comprises 4 a modulus of elasticity that is less than a modulus of elasticity of the tower wall 1 and / or a modulus of elasticity of the bushing 2 , The lower modulus of elasticity of the solder body 4 allows a certain degree of deformation, for example in case of temperature fluctuations or oscillations of the tower wall 1 , In the exemplary embodiment shown, the modulus of elasticity of the solder body is 4 1.2 × 10 ⁵ N / mm ² . The steel used here is about 2.1 × 10 ⁵ N / mm ² .

The melting temperature of steel varies depending on the grade of steel, but in most cases is at least 1400 ° C. As a lot of the solder body 4 has a melting temperature of at least 900 ° C and at most 1200 ° C, the solder can be melted without causing a melt of the steel of the tower wall 1 or the socket 2 comes. As a result, the fastening arrangement 5 a higher notch class are assigned as mounting arrangements, a welded joint between the wall 1 and the fastener 2 exhibit.

In 2 is a Wöhler curve shown. With a Wöhlerversuch a vibration resistance, more precisely, a fatigue strength and fatigue strength of materials or components (component Wöhlerversuch) is determined. For this purpose, the test bodies are loaded cyclically, usually under a sinusoidal load-time function.

In the 2 the vertical axis shows a longitudinal stress swing width Δσ in N / mm ² , and the horizontal axis shows the number of load changes N.

The 4 shows a plan view and a cross section of a typical sample body 9 , who for the Wöhlerversuche the 2 has been used.

For the carried out Wöhlerversuche different sockets 2 each centered on a metal strip 10 welded or soldered. The metal strip 10 of the specimen 9 here is the tower wall 1 simulate and has the following dimensions: 500 × 80 × 20 mm. The socket 2 is cylindrical and has a diameter of 30 mm. The socket 2 is by means of a fillet weld 4 ' connected to the metal strip. The fillet weld 4 ' can be designed as a weld or solder seam depending on the experiment. The fillet weld 4 ' in this case has a thickness of 7 mm. The stress was cyclic and sinusoidal with a frequency of 10 to 20 Hz to a break in the metal strip 10 and / or socket 2 and / or fillet weld 4 ' , Next is a load ratio R = 0.1 (underload / top load); Zugschwellbereich).

In the 2 are triangles with the reference numerals 17 provided, the triangles 17 Results of vibration tests with welded bushings 2 represent. Next are diamonds with the reference number 18 provided, with the rhombuses 18 the jacks 2 by arc soldering to the metal strip 10 are attached.

It can be seen that for the jacks 2 , which by means of arc soldering to the metal strip 10 are fixed, compared to jacks 2 , which by means of a welded connection with the sheet metal strip 10 are connected, at the same load level results in about a doubling of the sustainable load changes.

3 shows fillet welds 14 . 24 a weld (left) and an arc soldering (right). In the left part of the figure is a fastener 12 at structural steel 11 over a weld 14 connected, while in the right part of the figure a fastener 22 at structural steel 21 by means of an arc soldering over a soldering seam 24 a solder body is connected. During the construction steel 11 in the left part of the figure is significantly weakened by the weld, it can be seen in the right part of the figure that the soldering has a small effect on the structural steel 21 Has. Consequently, in the arrangement of the 3 to the left of a notch class 80 be assumed while the arrangement of the 3 on the right has a notch class of about 100 to 110.

• - Anordnen eines Befestigungselements 2 an einer Wand 1 eines Turms einer Windkraftanlage;
• - Schmelzen des Lots mittels eines Lichtbogens oder mittels eines Schweißgeräts, wobei das Lot hierbei auf das Befestigungselement 2 und/oder auf die Turminnenwand 1 aufgebracht wird, wobei die Wand 1 und das Befestigungselement 2 in einem festen Aggregatszustand bleiben;
• - Bilden eines Lotkörpers 4 mit einer Kehlnaht; und
• - Verbinden des Befestigungselements 2 mit der Wand 1 mittels der Kehlnaht des Lotkörpers 4.

The invention also provides a method for producing the fastening arrangement 5 provided. The method comprises the steps:

• - Arrange a fastener 2 on a wall 1 a tower of a wind turbine;
• - Melting of the solder by means of an arc or by means of a welding apparatus, wherein the solder in this case on the fastener 2 and / or on the tower wall 1 is applied, wherein the wall 1 and the fastener 2 remain in a fixed state of aggregation;
• - Forming a solder body 4 with a fillet weld; and
• - Connecting the fastener 2 with the wall 1 by means of the fillet weld of the solder body 4 ,

The solder can be supplied in particular during the process variants MSG arc melting and WSG arc melting during the process. An arrangement of the solder before the process is often typical for soft and brazing processes with flame. In this respect, processing by means of arc soldering is process-technically simpler compared to conventional soldering methods.

During the melting of the solder and the production of the solder body 4 is a protective gas, typically argon or argon-rich mixed gas or in some cases, helium or helium-rich mixed gas supplied, so that oxidation of the materials used can be prevented or reduced. Alternatively, to prevent or reduce the oxidation of the bonding partners, there may also be a vacuum, for example a rough vacuum or a fine vacuum. To the method further steps can be added, which with the features of the fastening arrangement described above 5 correspond.

Only features described in the figures can be combined with features from the above description and claimed individually.

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

• WO 2010/058037 A2 [0010]
• DE 202012009889 U1 [0016]
• EP 2078850 A2 [0016]
• DE 202014104673 U1 [0017]
• EP 2574779 A1 [0017]
• EP 2574780 A1 [0017]
• EP 2187049 A2
• WO 03/067038 A1 [0019]
• DE 202016101425 U1 [0020]

Claims (13)

Fastening arrangement (5) for fastening components to a wall (1) of a tower of a wind power plant, wherein the fastening arrangement (5) comprises a fastening element (2) and a brazing body (4), wherein the fastening element by means of the brazing body (4) fixed to the Wall (1) is connected, characterized in that the solder body (4) is formed as a fillet weld. Fastening arrangement (5) according to a Claim 1 , characterized in that the fastening element (2) and the wall (1) at least partially abut each other. Fastening arrangement (5) according to one of the preceding claims, characterized in that the solder body (4) is annular or U-shaped. Fastening arrangement (5) according to one of the preceding claims, characterized in that the wall (1) has a first surface and the fastening element (2) has a second surface, said surfaces being substantially perpendicular to each other, and the brazing body (4 ) forms a solder bridge between the first surface and the second surface. Fastening arrangement (5) according to one of the preceding claims, characterized in that the solder body (4) is produced by arc joining, in particular arc soldering, and / or the solder body (4) is free of flux. Fastening arrangement (5) according to one of the preceding claims, characterized in that the fastening element (2) with an end face (8) is fixed to the wall (1) and comprises a through hole (3) extending from said end face (8). extending to one of said end face (8) opposite end face (9), and / or has an internal thread (6). Fastening arrangement (5) according to one of the preceding claims, characterized in that the solder body (4) is formed by a Kupferbasislot, a Nickelbasislot, a Kobaltbasislot or a Eisenbasislot. Fastening arrangement (5) according to one of the preceding claims, characterized in that the solder body (4) has a lower modulus of elasticity than the wall (1) and / or the fastening element (2), wherein the modulus of elasticity of the solder body (4) is preferably less than 1 , 3 * 10 ⁵ N / mm ² . Fastening arrangement (5) according to one of the preceding claims, characterized in that the solder body (4) has a melting temperature of at least 900 ° C and / or at most 1200 ° C. Method for producing a fastening arrangement (5), comprising the steps: - Arranging a fastener (2) on a wall (1) of a tower of a wind turbine; - Melting of the solder, wherein at least the wall (1) remains in a solid state of aggregation; - forming a solder body (4) with a fillet weld; and - Connecting the fastener (2) with the wall (1) by means of the fillet weld of the solder body (4). Procedure After Claim 10 in which the steps of melting the solder and / or forming the solder body (4) take place with the introduction of an inert gas or in an at least partial vacuum. Method according to one of Claims 10 or 11 , characterized in that the solder is melted by an arc. Method according to one of Claims 10 to 12 , characterized in that the fastening arrangement (5) of Claims 1 to 9 will be produced.

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