DE102011003602A1 - Backup system for rotor blade of wind turbine, has longitudinally extended and tension transmitting main strand element formed in rotor blade, and attached to several elongate and tensile load transmitting auxiliary group elements - Google Patents

Abstract

The backup system comprises longitudinally extended and tension transmitting main strand element (20) formed in the rotor blade and several elongate and tensile load transmitting auxiliary group elements (21,22) engaged with the main strand element. A stop device (50) is connected in the region of the rotor blade root (2). The main strand element and auxiliary group elements are connected with two-dimensional structures of the rotor blade at attachment points (33-36). The webs (11,12) or strap are formed in the rotor blade inner surface.

Description

The invention relates to a safety system for a rotor blade of a wind energy plant, wherein the rotor blade extends along a longitudinal extent of a rotor blade root substantially to a rotor blade tip and at least one region in which the rotor blade has an aerodynamic cross-sectional profile having a profile leading edge and a profile trailing edge which are connected via a suction side and a pressure side of the cross-sectional profile. The invention further relates to a corresponding rotor blade and a corresponding wind turbine.

The forces acting on the rotor blades are of a very dynamic nature. It happens in individual cases that parts of rotor blades of a wind turbine dissolve and fall in the vicinity of the wind turbine to the ground. This is done especially in cases of uncontrolled accelerations of the rotor of the wind turbine, for example, in strong winds or in case of failure of control and / or braking systems. Tower contact with the rotor blade structure also has a catastrophic effect, which can occur when a rotor blade is deflected so far in strong wind that its tip touches the tower at the lower reversal point of its circulation. In this case, the usually a shell construction having rotor blade structure is permanently damaged.

In today's modern and material-efficient production and calculation methods, the properties of the materials used, in particular glass or carbon fiber reinforced plastics, are being exploited ever better. Nevertheless, rotor blades have a relatively large mass. With increasing power of a wind turbine, the rotor diameter and the rotor blade mass also increase. To limit the acceleration of these large masses, the wind turbines are operated at low speeds.

In the course of a revolution, changing loads act on the rotor blades. One reason for this is the weight of the rotor blade, which always acts downwards. Another reason lies in the irregular and generally from the ground upwards increasing wind field. The ground-level boundary layer is responsible for this wind gradient. These changing forces during the rotation of the rotor lead to constantly changing bending loads of the rotor blade. With increasing wind speed, the turbulence intensity of the wind also increases and the gusts reach much higher wind speeds, which in turn results in much heavier loads on the rotor blades.

With increasing rotor blade length, the rotor blades are softer in the circumferential direction and with respect to their torsional rigidity. This can lead to a superposition of bending vibrations in the circumferential direction and torsional vibrations about the rotor blade longitudinal axis. In certain wind conditions, this superposition leads to a self-generating vibration, the so-called "fluttering". These are aerodynamically induced vibrations.

Additional stresses on the material also represent climatic and weathering effects. Rotor blades must be able to function without permanent damage in a temperature range of approx. -20 ° C to + 50 ° C. Erosion damage from rain, hail and dust can be observed at the leading edge of the rotor blade. Wind turbines also represent potential attractions for lightning during thunderstorms. Here, experience has shown that the blade tips are particularly affected. It must currents up to 100 kA be derived as possible without much damage. For this purpose, lightning protection systems are installed inside the rotor blade.

These different sources of stress can lead to failure of the rotor blade structure. This may be spontaneous damage due to high loads or fatigue damage that may occur after longer exposure even at lower loads. Characteristic damages in fiber composite structures are fiber breaks, intermediate fiber breaks and delaminations. Fiber breakage directly damages the fibers of the laminate. By tearing the fibers, the material loses its tensile strength in the direction of the affected fiber layer. Inter-fiber breaks are characterized by the fact that the matrix is damaged, ie the plastic or the resin in which the fibers are embedded. In a delamination, two superposed laminate layers separate from each other. Also manufacturing defects, z. As air pockets in the laminate or improper bonding, have a negative impact on the supporting structures. Just in the interior of the rotor blade structure lying defects are usually not early recognizable. Therefore, the design of rotor blades with sufficient tolerances, so as to be able to tolerate defects in the interior of the rotor blade structure.

The damage patterns in rotor blade damage differ in the size of the demolished fragments. If the segments are smaller than 1 m ² and the mass is less than 10 kg, these are torn small parts. For segments larger than 1 m ² with a mass greater than 10 kg partial structures are torn off. If the rotor blade breaks off at the hub, the overall structure of the rotor blade breaks off. The latter case is less than 2% of all Cases the rarest. Significantly more often, small parts are being demolished. With around 90% of all claims, the demolition of substructures is the most common. Tower touches are comparatively rare, but produce a comparatively large number of fragments.

The demolition of the entire structure and partial structures, but also of small parts, holds a great potential for danger. In wind power plants of the multi-megawatt class, the individual rotor blades weigh several tons. They achieve blade tip speeds of approx. 80 m / s. The kinetic energy stored in the system endangers the environment when the blade or part of it breaks off due to rotor blade failure. Depending on the rotational speed of the rotor, the size of the rotor blades, the geometry of the demolished structure, the wind speed and the position of the rotor blade during demolition, the flight lengths of the fragments are from a few meters to several hundred meters.

In order to minimize the risk to the environment in rotor blade failure, the kinetic energy released when a rotor blade segment is broken off must be absorbed, so that no damage to the surroundings of the wind turbine is caused. In this case, the basic function of the rotor blade must not be impaired to extract energy from a wind field, to convert it into a rotational movement of the rotor and to conduct it to a generator. Since the type and position of demolished segments are distributed over the rotor blade, the arrangement of such a fuse in a rotor blade is designed to be blade-specific in such a way that all areas of the blade can be reached thereby, ie. H. Both smaller fragments in the area of the rotor blade tip and a break in the area of the blade root are covered. At the same time, the rotor blade should be loaded with the least possible additional weight.

The invention is therefore based on the object to provide a safety system for a rotor blade of a wind turbine available, and a corresponding rotor blade and a corresponding wind turbine, with a risk to the environment is minimized in rotor blade failure, while the construction of the rotor blade is not affected. The rotor blade should not be made significantly heavier. In addition, the security system should be structurally simple and without much time overhead, especially during manufacture, be installed in a rotor blade structure.

This object is achieved by a wind turbine rotor blade securing system, the rotor blade extending along a longitudinal extent extending from a rotor blade root substantially to a rotor blade tip and having at least a region in which the rotor blade has an aerodynamic cross-sectional profile, a leading edge and Having a profile trailing edge, which are connected via a suction side and a pressure side of the cross-sectional profile, wherein the securing system in the interior of the rotor blade at least one at least partially along the longitudinal extent of the rotor blade arranged longitudinally extended and tensile load transmitting main strand element and a plurality of elongate and tensile load transmitting Nebenstrangelementen , which are connected to the at least one main strand element, wherein the at least one main strand element with at least one stop device in the de The rotor blade root is connected, wherein the at least one main strand element and / or the plurality of secondary strand elements are connected at a plurality of attachment points with planar structures of the rotor blade, in particular with an inner surface of the rotor blade, a web or a belt.

The invention is based on the basic idea that elongated tensile load-transmitting main string elements and secondary string elements can be laid with little effort inside a rotor blade. Such Hauptstrangelemente are tensile and have a low weight. They shall be designed so as to be able to absorb the forces occurring in rotor blade failure, in particular the centrifugal forces acting on the fragments of the rotor blade, and to hold the fragments without cracking.

The design with at least one main line element and a plurality of secondary line elements makes it possible to secure rotor blade structures, ie, in the context of the present invention, in particular the shells of the rotor blade, webs and / or belts, at virtually small distances from each other virtually everywhere. Central here are the main string elements that hang the securing system on a stop device in the area of the rotor blade root. The stop device is preferably connected directly to the rotor hub in the region of the rotor blade root, so that the rotor blade is still held even when the rotor blade is completely torn off. From this one or more main strand elements branch off secondary strand elements, which are distributed over the inner structure of the rotor blade with the rotor blade and distribute holding forces on the inner surface of the rotor blade and on the straps and webs of the rotor blade and forward them to the main strand or the elements.

Such a system of protection based on main and secondary strings can be installed with little effort in a rotor blade or can be installed during the manufacture of the rotor blade. There are tensile, lightweight materials that are suitable for this purpose. In addition, with the points of attachment distributed over the rotor blade structures, efficient use of material is provided since the rotor blade structures, ie the shells, straps and lands themselves have a net-like structure because of their fiber composite construction, relatively relieving the forces which destroy the rotor blade Distribute over a large area, so that, where appropriate, the points of attachment of the strand elements to the rotor blade structures can be relatively far apart, for example one or more meters apart. This property of the fiber composite materials used in modern rotor blades is utilized to save material for the security system according to the invention.

Since the main string members in the case of a rotor blade failure absorb the forces acting on several Nebenstrangelemente forces, the main string members are preferably designed to be stronger than the Nebenstrangelemente. The main strand elements and the secondary strand elements may also consist of a plurality of main strand elements or secondary strand elements which are connected to one another or are suspended from one another.

The number, arrangement and connection of the securing system within the rotor blade are to be designed blade-specifically so that as far as possible all areas of the blade are reached, ie both smaller fragments, in particular in the area of the rotor blade tip, fractures in the area of the blade root and damage events lying between these extremes. In this case, the largest possible number of fragments is held on the system with the security system according to the invention. The materials chosen for the securing system, in particular the strand elements, should be able to absorb approximately the same strains in the area of the leaf straps and shell parts as the existing rotor blade structure. If the materials are significantly stiffer than the rotor blade structure, delamination may occur in the rotor blade structure or between the components of the backup system and the rotor blade structure.

Preferably, secondary string elements are distributed along the longitudinal extent of the at least one main strand element and are connected to the at least one main strand element. In this case, the secondary string elements branch off from the main string element in a tree-like structure, in particular they run transversely to the main string element. This takes place in particular advantageously in the region near the blade root near the rotor blade, where it has a large extent between the profile leading edge and the profile trailing edge. The main strand element can pass through the entire length of the rotor blade or only part of the length of the rotor blade.

The secondary string elements preferably extend at least in sections transversely and / or at least in sections substantially parallel to the longitudinal axis of the rotor blade. The case of transversely running the secondary strand elements can advantageously be combined with the secondary strand elements distributed along the longitudinal extent of the main strand element being connected to the at least one main strand element. However, they can also continue from one end of the main strand element in the longitudinal direction of the rotor blade and branch off after a longitudinal section and run transversely. Also, for example, branch off from the end of a main strand element a plurality of secondary strand elements and further in sections parallel to the longitudinal axis and parallel to each other. Substantially parallel to the longitudinal direction of the rotor blade is also understood here to mean that a secondary strand element runs in sections parallel to the profile leading edge or to the trailing edge of the profile or in a direction extending between the longitudinal axis and the profile leading edge or profile trailing edge. This is the case in particular in the ever-narrowing area of the blade tip.

The abovementioned geometries allow a force-flow-oriented arrangement of main and secondary strand elements, so that no stress peaks are produced by sudden changes in cross section when the force is introduced into the strand elements.

In a particularly preferred embodiment of the security system according to the invention, the at least one main line element and / or at least one secondary line element is designed as a steel cable or a plastic cable, wherein in particular the material used for the cable has a tensile strength of more than 500 Nmm ^-2 , in particular more than 1500 Nmm ^{. 2} , in particular more than 2500 Nmm ^-2 . Higher tensile strength results in the corresponding rope having a smaller cross section and a smaller mass being usable. A particularly tensile plastic rope is known under the brand name "Dyneema". Corresponding ropes have tensile strengths of in some cases more than 3000 Nmm ^-2 . A main strand of this material may have a diameter of a few centimeters. The main string elements and also the secondary string elements among one another can be dimensioned differently, depending on the expected occurring loads.

The design as a steel cable is advantageously used as a conductor in a lightning protection system.

With appropriate ropes, the safety system has a weight that does not exceed the tolerance field of the rotor blade, for example 5% of the self-weight of the rotor blade. If this tolerance field is exceeded, otherwise a new calculation of the load assumptions for the rotor blade structure would have to be made. The magnitude of the forces introduced into the security system depends on the location of the break in the blade, the weight of the fragment and its acceleration. The maximum force results in the blade connection at demolition of the entire rotor blade. The main load direction of the forces acting on the construction lies in the radial direction, so that in particular stresses arise in the pulling direction. When the forces are introduced into the securing system, there is a longitudinal expansion of the strand elements, in particular ropes. The limit of elongation is to be set to the elastic deformation range of the materials, otherwise failure of the components of the safety system will occur. Due to the longitudinal expansion of the security system or the strand elements, part of the kinetic energy released is converted into friction and heat by means of deformation work. Thus, a damping of the power surge is achieved.

Advantageously, the at least one main strand element is at least partially connected to a shell part, a web or a belt of the rotor blade. Also, the main strand element itself thus serves in case of damage to maintain the rotor blade structure.

In a particularly advantageous development of the securing system according to the invention, the at least one main strand element is arranged at least in sections along a zero line of a web of the rotor blade. The main bending direction of modern rotor blades is that in the plane of the webs or transversely to the upper shell and the lower shell of the rotor blade and the belts that absorb these bending loads and forward to the rotor blade root and the rotor hub. The zero line on a web is the line in which the web material is neither compressed nor stretched during the bending of the rotor blade, but merely undergoes a curvature. Since the strand elements, in particular the ropes are not compressed or stretched on the zero line, this arrangement of the main string members is particularly gentle on materials, so that they retain their high tensile strength even after several years of operation, especially over the entire life of the rotor blade.

To anchor the securing system is preferably a, in particular segmented, flange provided, which has at least one eyelet as a stop device, which is bent in particular relative to the flange by 90 °. Thus, the eyelet runs parallel to the rotor blade structure. In order to get as close as possible to the rotor blade structure, the flange ring or the flange ring segments are in particular preferably provided with oblong holes. With these measures, the bending load in the bending edge between eyelet and flange ring is reduced to a minimum. Further advantages of the flange ring are the distribution of the introduced force on several blade bolts and the possibility to use this flange ring in all types of wind turbines.

Alternatively or in addition to the stop device in the form of an eyelet on a flange ring, a connection to the screw connection of the blade connection is advantageously provided as a stop device. Here, the main string elements can be added to the leaf pins, in particular, extended leaf bolts can be used.

Due to the structure and the dimensions of the rotor blade also preferably a division of the security system takes place at a certain radius. Leaf root side, for example, a tree structure and leaf tip side, a parallel structure of main string members and Nebenstrangelementen be used. This is done in particular because the production process, in which the two half-shells are joined together in the case of an assembly of upper and lower shell, makes it impossible to realize the same property connection between the strand elements over the entire rotor blade length. As a result, the strand elements from the front area of the rotor blade on the shells and straps must be fully advanced on the blade tip side. After the rotor blade is closed, the connection to the remaining strand elements can take place.

The attachment points represent the link between the rotor blade structure and the strand elements. On the basis of the attachment points, an at least partially cohesive connection of the main and secondary strand elements with the rotor blade structure is achieved, in particular.

Preferably, a point of attachment as Überlaminierung a resting on a flat element of the rotor blade main strand element or Nebenstrangelements with a piece of belt material, glued to a flat element of the rotor blade or laminated fastener with a mounting lug or as one or more a web penetrating bolt, or on both sides of the web is supported in each case by a metal plate relative to the web or are and the or on at least one side of the web overhanging the web or projecting formed.

The first variant is particularly suitable to connect a main strand element or a secondary strand element at several points along its longitudinal extent with a flat rotor blade structure, ie sheet shell, strap or web, in which it is overlaminated with a Gurtmaterialstück. The second alternative in the form of a fastening element with a fastening eye which is adhesively bonded or laminated onto a flat element of the rotor blade likewise provides a flat cohesive anchoring of the fastening element. Alternatively, such a fastening element can also be embedded and laminated in the rotor blade structure. The third alternative with bolts is particularly suitable for the internal webs. They also serve to make a connection of strand elements on opposite sides of a web.

Preferably, a main strand element or a secondary strand element is terminated at one end with a cable lock, with a casting, with a ferrule with thimble or with a, in particular with a thimble reinforced, forming an eye splice end. Especially with ropes, splice connections are particularly durable and unbreakable. A cable lock or cable eye end can be securely and permanently connected to the eyelets or the external threads of bolts of the attachment points.

The connection of at least one secondary strand element to the at least one main strand element is preferably a node connection with a clamping node, which clamps in one direction when subjected to tensile load, or a splice connection. A corresponding node connection is known for example as Stopperstek and is often used in shipping, z. B. when towing several boats on a tow. It is important to ensure that the Stopperstek only clamps in one direction under tensile load. With a Stopperstek the side strands can be positively connected to the main strands, at the same time the secondary strands are secured against axial slippage in the loading direction along the main strand. Thus, a tree-like branching of the main strand structure of the secondary strands can be realized. In contrast, a splice connection is even more resilient, but also more expensive to manufacture.

In the case of rotor blades, which have a balancing chamber, in particular in the region of the rotor blade tip, preferably at least one attachment point is arranged on a balancing chamber of the rotor blade. Thus, the balancing chamber, which serves to balance the rotor blade with respect to an optimal concentricity of the rotor blade, secured against tearing off rotor blade failure.

Preferably, components of the security system are substantially overlaminated at the locations where they abut surfaces of portions of the rotor blade or contact surfaces of portions of the rotor blade. Corresponding parts of the rotor blade are inner surfaces of the rotor blade shells, straps and webs. Preferably, some or all of the components of the security system which are or may be in direct contact with the rotor blade structure are secured against rattling by means of a laminate layer or by over-curing or greasing.

The object underlying the invention is also achieved by a rotor blade of a wind energy plant with a safety system according to the invention described above and by a corresponding wind energy plant with a rotor blade according to the invention with a safety system according to the invention described above.

The advantages, properties and features mentioned for the safety system according to the invention also apply to the rotor blade according to the invention and the wind energy installation according to the invention, which have the safety system, without restrictions.

The invention will be described below without limiting the general inventive idea by means of embodiments with reference to the drawings, reference being expressly made to the drawings with respect to all in the text unspecified details of the invention. Show it:

1 a schematic cross-sectional view through a rotor blade,

2 a schematic cross-sectional view through a rotor blade with a security system according to the invention,

3 a schematic cross-sectional view through a rotor blade with a security system according to the invention in an alternative configuration,

4 a schematic cross-sectional view through a rotor blade with a security system according to the invention in an alternative configuration,

5 a schematic cross-sectional view through a rotor blade with a security system according to the invention in an alternative configuration,

6 a schematic plan view of a rotor blade with a security system according to the invention,

7 1 is a schematic side view of a part of a rotor blade with a part of a safety system according to the invention,

8th a schematic cross-sectional view of a point of attachment according to the invention,

9 a schematic side view of the point of attachment 8th .

10 a schematic cross-sectional view of a point of attachment according to the invention,

11 a schematic cross-sectional view through a connecting point according to the invention,

12 a schematic cross-sectional view through a connecting point according to the invention,

13 a schematic cross-sectional view through a connecting point according to the invention,

14 a schematic cross-sectional view through a connecting point according to the invention,

15 a schematic representation of a shock buffer,

16 a schematic representation of a shock buffer,

17 a schematic representation of a shock buffer,

18 a schematic representation of a shock buffer,

19 a schematic cross-sectional view through a rotor blade with a security system according to the invention,

20 a schematic cross-sectional view through a rotor blade with a security system according to the invention,

21 a schematic cross-sectional representation through a point of attachment at the end of a secondary strand,

22 a schematic side view of the point of attachment according to 21 .

23 a cross-sectional view through a connection position of a security system according to the invention,

24 a schematic side view of a stop device according to the invention and

25 a cross-sectional view through the stop device according to 24 ,

In the following figures, identical or similar elements or corresponding parts are provided with the same reference numerals, so that a corresponding renewed idea is dispensed with.

In 1 is a rotor blade 1 with its aerodynamic cross-sectional profile 4 schematically shown in cross section, that of a profile leading edge 5 via a suction side 7 and a print page 8th to a profile trailing edge 6 leads. The suction side 7 is by an upper half shell 9 realized, the pressure side 8th through a lower half shell 10 , The half-shells 9 . 10 are usually constructed in a fiber-reinforced plastic construction, with glass fibers or carbon fibers embedded in a resin matrix. Inside the rotor blade 1 Structures are arranged that increase the stability of the rotor blade 1 produce, namely webs 11 . 12 as well as main straps 13 . 14 on the suction side 7 and the print side 8th and optional front side straps 15 . 16 near the profile leading edge 5 and rear side straps 17 . 18 near the profile trailing edge 6 , The straps 13 to 18 consist of layers of fiber-reinforced plastics with substantially parallel fiber orientation, which are the main load of the bending moments of the rotor blade 1 pick up during operation and transferred to the rotor blade root. The bridges 11 . 12 stabilize the shape of the aerodynamic cross-sectional profile 4 during operation of the wind energy plant.

In 2 is a rotor blade in a schematic cross section 1 as in 1 shown, however, the straps 13 to 18 are not shown for clarity. The rotor blade 1 in 2 has a security system according to the invention with two Hauptstrangelementen 20 , each on the zero line at the jetties 11 . 12 run. From the two main strands, in the longitudinal direction of the rotor blade 1 run, branches branch lines 21 off to the upper half shell 9 and to the lower half shell 10 in the front and in the back of the half-shells 9 . 10 lead, as well as two side strands 21 leading to the main straps 13 . 14 lead and provide starting points. The arrangement of the main string elements 20 in the zero line of the webs 11 . 12 leads to a particularly low burden of Main train elements 20 during normal operation of the wind turbine.

The main string elements shown in this and the following figures 20 and minor strings 21 . 22 consist in particular of the lightweight and high-tensile plastic rope made of Dyneema made of high-strength polyethylene fibers or less specialized plastic fibers or ropes or steel cables.

In 3 is a rotor blade 1 with an alternative configuration of a security system according to the invention. In this case, branch from a central single main string element 20 a series of minor strings 21 off, which in turn is the upper half shell 9 and the lower half shell 10 contact in the same places as this in 2 was shown. In this case, the main strand 20 in the cutting plane, the in 3 is shown, not with a flat structure of the rotor blade 1 connected. This configuration provides increased flexibility of the structure of the security system.

In 4 is another alternative configuration of a safety system in a rotor blade 1 shown. To the upper half shell 9 and the lower half shell 10 at the same positions as in 2 and 3 shown to secure, is at the main belt 13 the upper half shell 9 and at the main belt 14 the lower half shell 10 one main strand element each 20 relocated and contacted. From each of these branches a Nebenstrangelement 21 in the direction of the profile leading edge 5 and in the direction of the profile trailing edge 6 off, by the footbridges 11 and 12 to the connecting points in the front and back box of the profile 4 be directed. This will be compared to the solutions 2 and 3 two minor strings 21 saved. The main string elements 20 are however at the straps 13 . 14 arranged and experienced in the operation of the rotor blade 1 hence a continual compression and elongation, resulting in a gradual fatigue of the main string members after a prolonged period of operation 20 leads. These must therefore be designed with slightly higher tolerances than in the case of the variants 2 or 3 ,

In 5 is another configuration of a safety system according to the invention in a rotor blade 1 shown in cross section. Similar to in 2 run along the zero line of the webs 11 . 12 two main strings 20 , There are minor strings in this section 21 in the longitudinal direction of the rotor blade 1 at the points of attachment to the upper half shell 9 and the lower half shell 10 as in the 2 to 4 , At another point along the longitudinal extent of the rotor blade 1 These are the main strings 20 connected. This can for example be like in 2 be shown configured, so that the embodiments of the 2 and 5 as cuts through a rotor blade 1 at different points of the rotor blade 1 can be viewed. Alternatively to the arrangement of the main string elements 20 and the Nebenstrangelemente 21 in 5 can also use the main string elements 20 be executed as those strand elements that are on the strap 13 the upper half shell 9 and the belt 14 the lower half shell 10 run. It can also use the four central strands as main strands 20 be formed, wherein only the two front and the two rear strands are each formed as a side strands, at another point with the main strands 20 in the zero line of the webs 11 . 12 are connected.

In 6 is a schematic plan view of a rotor blade 1 represented by a rotor blade root 2 to a rotor blade tip 3 extends. Stege 11 . 12 are also shown. At the rotor blade root 2 are connecting bolts 51 as well as two lifting points 30 for two main strands 20 shown, which are parallel to the longitudinal axis of the rotor blade 1 towards the rotor blade tip 3 to get lost. Im in 6 As shown, the main string elements run 20 up to a little less than the middle of the longitudinal extent of the rotor blade 1 , There is a connection point 40 , In the blade root side section of the rotor blade 1 Branch at secondary strands at regular intervals 21 off to the profile leading edge 5 and the profile trailing edge 6 substantially perpendicular to the main string members 20 run. The configuration of the main string elements 20 and the Nebenstrangelemente 21 can in this case example according to the configuration 2 be educated.

The Nebenstrangelemente 21 make knots at connection points 31 to the main string elements 20 at. These connection points are preferably designed as splices or as a clamping node, for example Stoppersteks. The connection points 31 can also be used as starting points 33 to the footbridges 11 . 12 be educated. The Nebenstrangelemente 21 each ends at approximately equal distances to the webs 11 . 12 at the upper and lower shells 9 . 10 in connecting points 35 , Distances between the connection points 31 along the main rope elements 20 may be, for example, 2 to 3 m. The length of the secondary string elements 21 towards the profile leading edge 5 is less than the length in the direction of the profile trailing edge 6 , This is the shape of the aerodynamic cross-sectional profile 4 owed, the profile trailing edge 6 out further than the profile leading edge 5 out.

Just before half the length of the rotor blade 1 end the main string elements 20 in a connection point 40 , where also connecting points 34 provided to the web. At the connection point 40 There are also connection points 32 to subsequent secondary strings 22 in the longitudinal direction of the rotor blade 1 are arranged. Each three Nebenstrangelemente 22 run on the upper half shell 9 and on the lower half shell 10 , To create a dense sequence of attachment points, the longitudinal side-branch elements are 22 in the leaf-tip area at regular intervals with connecting points 36 Mistake. The Nebenstrangelemente 22 are each with the main string elements 20 in the area of the junction 40 connected. The Nebenstrangelemente 22 run to the rotor blade tip 3 , As in the front area, ie the rotor blade tip 3 out, the distance between the profile leading edge 5 and profile trailing edge 6 is getting smaller, also run the three Nebenstrangelemente 22 in this area towards each other.

Just before the rotor blade tip 3 has the rotor blade 1 at its profile trailing edge 6 a balancing chamber 23 on, at a point of contact 37 to the back secondary strand element 22 is linked. Thus also the balancing chamber becomes 23 in case of structural failure. The Nebenstrangelemente 22 and 21 Forces from fragments lead to the main strands 20 continue, in turn, all the forces in the attachment points 30 at the rotor blade root 2 conduct. The net structure of straps, webs and half shells ensures a further distribution of forces, so that with the in 6 structure shown by way of example extensive retention of broken structural elements of the rotor blade 1 is possible.

In 7 is part of the backup system according to 6 shown schematically from the profile leading edge. At the rotor blade root 2 of the rotor blade 1 are the connecting bolts 51 recognizable as well as a flange ring 50 , the two lifting points 30 for main string elements 20 having. The structure thinning to the right creates a bridge 12 This has in the area of the rotor blade root 2 a substantially semi-elliptical web opening 12a , The main string elements 20 are with connecting points 33 at the jetty 12 attached. Just behind the bridge opening 12a bend the two main string elements 20 in the direction of the zero line of the webs 11 . 12 from. Both main string elements 20 then run along the zero lines at the webs 11 . 12 continue to the junction 40 where she is on a base plate 41 are moored. The representation in 7 represents the two main string elements 20 In fact, they are, as in 6 represented, arranged offset in two planes to each other and overlap in the 7 only in perspective shortening.

In 8th is in cross-section schematically a point of attachment 36 shown, wherein a longitudinal Nebenstrangelement 22 at one of several points along its longitudinal extent on a flat rotor blade structure 60 is linked. The rotor blade structure 60 In the case shown, a structure of a carrier material with a laminate layer 61 is covered. On this laminate layer 61 is a minor issue 22 in an adhesive resin 62 embedded and this structure of collateral element 22 and adhesive resin 62 from a polyamide belt 63 flat covered. Polyamide straps are widely used as lifting straps. The polyamide belt 63 is on both sides of the Nebenstrangelements 22 with another laminate layer 64 fixed. This cross section may be at several points along the minor strand element 22 , for example at intervals of 1 to 3 meters, are repeated. Important here is the strength of the Polyamidgurts 63 and the surface lamination of the polyamide belt 63 , which is a large area cohesive connecting point of the Nebenstrangelements 22 to the rotor blade structure 60 represents.

In 9 is the starting point 36 out 8th shown schematically from the side. The rotor blade structure 60 and the first laminate layer 61 are again shown on top of each other. Left and right is the secondary string element 22 to recognize that continues in both directions. With a close-meshed hatching is the polyamide belt 63 characterized, which is about the Nebenstrangelement 22 extends and at its edges by another laminate layer 64 is covered. The length of this point of attachment 36 may, as well as its width, preferably between 5 and 30 cm, for example between 10 and 20 cm. In plan view, such a point of attachment 36 square or rectangular or have another shape, depending on the surrounding rotor blade structures, for example limited by the profile trailing edge 6 or to the profile leading edge 5 available space.

In the 10 to 14 are further inventively provided connecting points 33 . 35 and 36 shown. The rotor blade structure 70 each is a rotor blade structure 70 in sandwich construction, in which an intermediate layer 73 For example, from a foam material or balsa wood, of two laminate layers 71 . 72 is enclosed. The laminate layers 71 . 72 can be fiber reinforced plastic layers. Typical applications for rotor blade structures in sandwich construction, for example, webs 11 . 12 ,

In 10 is on the rotor blade structure 70 one side a side string element 22 longitudinally laid, which is overlaminated. Such a structure is slightly faster and easier to produce than the structure 8th and 9 and may be sufficient especially for smaller rotor blades.

A more complex production requires the starting point 36 out 11 in which in the intermediate layer 73 the rotor blade structure 70 an anchor element 75 is inserted, to which an eyelet 76 connects, the one-sided from the rotor blade structure 70 stands out and the as connecting point 36 for a main string element 20 or a minority element 21 . 22 can serve. Such an anchor 75 is very firm in the rotor blade structure 70 anchored. In this respect, such a starting point 36 especially suitable for high loads. However, it is also more expensive to produce than other connecting point structures.

In 12 is on the rotor blade structure 70 on one side a planar anchor element 75 by means of an adhesive seam 77 applied. The anchor element 75 again has an eyelet, shown in cross-section 76 on. Again, there is a cohesive connection between the rotor blade structure 70 and the connecting element 75 . 76 that is easier to produce than the one in 11 shown and can also be attached later.

In 13 is an alternative variant in the configuration according to 12 shown. According to 13 is in the place of the point of attachment 35 into the interlayer 73 the sandwich structure a core 78 admitted. The anchor 75 is instead of a bond 77 with two connecting elements 79 with the laminate 72 connected to the sandwich construction. This connection point is already in the manufacture of the rotor blade by inserting the core 78 in the rotor blade structure 70 prepared in the appropriate place.

Another embodiment of a point of attachment 33 is in 14 shown. The sandwich rotor blade structure 70 also has a core in the intermediate layer at this point 78 on, which has a central opening. Through the central opening is a bolt 80 led, which on one side a bolt head 81 and on the other side an external thread 82 having. Between the laminate layers 71 and 72 on the one hand and the bolt head 81 and one on the external thread 82 screwed mother 83 On the other hand, each are washers 84 . 85 placed the screwing force over a large area on the laminate layers 71 . 72 distribute and thereby prevent their destruction or damage. On the external thread 82 of the bolt 80 For example, a cable lock can be screwed on. Also, a bolt with double thread, ie both sides arranged external threads, can be used at this point, for example, a main strand element 20 on one side with a minor string element 21 or 22 connect to the other side.

In the 15 to 18 Shown schematically are a plurality of damping devices that make it possible to mitigate the force impact that occurs in a rotor blade structure failure. In 15 is an impact limiter 90 in the form of an expansion element 94 shown at an anchor point 96 is attached. This has a length L ₀ before a collision impact. The impact force exerts on the expansion element 94 a force F out, which leads to an extension by the amount ΔL to a length L ₁ . In the expansion element 94 . 95 For example, it is a rope that responds to an impulse with an inelastic extension and thus contributes to a damping of the impulse.

In 16 is shown at an anchor point 96 an impact limiter 91 with a rope 97 is formed, which at one end a final thickening 98 and that by an outer guide body 99 and an inner guide body 100 is closely constrained. When a collision force exerts a force F in the direction of the arrow, the rope 97 pulled in the direction of the arrow, the rope 97 through the guide body 99 . 100 slips through. The guide body 99 . 100 in the process exert a strong frictional force on the rope 97 out. The frictional force dampens the impact force. The slippage of the rope 97 gets through the final thickening 98 stopped. The protruding end, ie the way of the rope 97 , may for example be 0.5 to 5 m, preferably 1 to 2 m. The final thickening 98 Alternatively, it can consist of a node.

In 17 is an impact limiter 92 shown schematically, consisting of a webbing 101 or a rope which is gathered at one point to a longitudinal extent in several turns and at this point by means of a sewing thread 102 is held together. In a collision, which acts with a force F on both sides in the direction of the arrow, also a force on the sewing thread 102 exercised, which gradually tears and gradually the turns of the webbing 101 releases. This construction also serves as a fall arrest limiter 92 ,

In 18 is an impact limiter 93 as a fluid damper 103 shown. This has a fluid in its interior 104 , For example, a hydraulic oil, which is housed in a chamber by a punch 105 in two sub-chambers 109 . 110 is divided. Before a collision with force F in the direction of the arrow is the stamp 105 that of a pole 106 is passed, which has a seal 107 into the first compartment 109 leads in, on the left side of the fluid damper 103 in 18 , Under Action of the force F becomes the stamp 105 in the fluid damper 103 pulled to the right. The fluid 104 flows through two or more openings 108 from the first compartment 109 into the second compartment 110 , This happens relatively slowly, so that the power surge is attenuated.

In the following 19 to 23 Further preferred details of securing systems according to the invention are shown.

In 19 is a schematic cross section through a rotor blade 1 shown. In this case, main string elements run 20 each on the outside of the webs 11 . 12 in the respective zero line of the webs 11 . 12 , From this branch secondary strings 21 starting from the main string elements 20 starting initially parallel on the webs 11 . 12 and then turn to the upper and lower shells 9 . 10 snugly in the direction of the profile leading edge 5 and the profile trailing edge 6 run. They can also have one or more connecting points on the dock 11 . 12 and / or on the half-shells 9 . 10 of the rotor blade 1 to have. This in 19 represented cross-sectional profile corresponds to a cross section through the rotor blade 1 according to 6 leaf root side. relative to the junction 40 , that is, the location of a branch of transverse Nebenstrangelementen 21 from the main string elements 20 ,

In 20 is another cross section through the aerodynamic cross-sectional profile of the rotor blade 1 according to 6 shown, but blade tip side of the joint 40 , The cross-sectional profile is also corresponding to the cross-sectional profile 19 rejuvenated. At this point, only secondary strings run 22 in the longitudinal direction of the rotor blade 1 ,

In the 19 and 20 are ends of minor strings 21 . 22 circled and marked with the letter A. This detail A is in the 21 and 22 shown schematically. It is a terminal, that is terminating, attachment point for a secondary strand element 21 . 22 , The presentation essentially corresponds to the presentation of a point of attachment 36 according to 8th , In contrast to 8th is shown, which is the secondary string element 21 . 22 forms a loop at its end with a final splice connection. In this case, the loop with the reference numeral 22 ' Mistake.

In 22 is this place according to 21 shown from the side. This representation corresponds to the illustration from 9 with the difference that at this point the secondary string element 22 do not continue to the right, but a loop 22 ' forms. The loop part 22 ' is to the left of the point of attachment with the tributary element 22 equipped with an end splice connection. This is a very resilient way of connecting a rope to itself. The polyamide belt 63 runs through the eye or the opening of the loop 22 ' , In this way, also the end point of the Nebenstrangelements 22 kept safe. Instead of a secondary strand element 22 It can also be a minor issue 21 according to 19 , Detail A, act.

In 23 is a connection point 40 shown schematically. The rotor blade elements with fiber-reinforced plastics are shown filled with rauted. This concerns the upper half shell 9 and the lower half shell 10 as well as the footbridges 11 . 12 , Sandwich construction methods are not shown separately in this case. The straps are in for clarity 23 been omitted.

Two main strings 20 run in the amount of the neutral line or zero line of the webs 11 . 12 so as not to be subject to the bending stresses resulting from the deflection of the rotor blade. Such constantly changing strains and compressions can lead to a fatigue of the ropes.

At the junction 40 shows each jetty 11 . 12 one base plate on each side 41 on, each having a plurality of openings. Through these openings are double threaded bolts 43 and single-threaded bolts 44 screwed. A middle bolt is used to attach a main strand element 20 , which is shown in cross-section, to the web 11 . 12 as shown in 14 , Above and below is on the same base plates 41 one single threaded bolt each 44 attached a rope lock with a nut 42 a minority element 22 clamped on the outside of the respective web 11 . 12 to the upper half shell 9 or to the lower half shell 10 runs and there at a distance to the jetty 11 . 12 in the longitudinal direction of the rotor blade 1 weiterverläuft. A double-threaded bolt 43 is at every jetty 11 . 12 also arranged. This results in a configuration of a bolt on the inside of a web 11 . 12 for the connection of the main straps and three bolts each on the outer sides of the bars 11 . 12 in which the secondary string elements 22 for the upper half shell 9 and the lower half shell 10 as well as the main string elements 20 be attached. For this purpose, preferably with the Schaubverbindungen nuts with screw locking after DIN 267-27 be used with adhesive coating. This ensures that every secondary strand element 22 non-positive and separate with a main string element 20 connected is.

The connection of the respective Nebenstrangelemente 22 and main string elements 20 he follows for example via symmetrical cable locks 42 attached to the bolt 43 . 44 be screwed. If the ropes of the string elements 20 . 21 . 22 without splice connection in the cable locks 42 are introduced, the loose ends of the ropes are knotted and so against slipping through the cable locks 42 to secure.

At the double-threaded bolt 43 are each on the inside and the outside of the bridge 11 respectively. 12 each a Nebenstrangelement 22 arranged, also along the footbridge 11 . 12 to the upper half shell 9 or to the lower half shell 10 run, there from the jetty 11 . 12 away and then in the longitudinal direction of the rotor blade 1 continue to run. In this way, secondary strings become 22 in the space between the bars 11 and 12 each at the upper half shell 9 and the lower half shell 10 and laid in the front box and in the rear box.

In the 24 and 25 an inventive stop point is shown. In 24 is on the left side a flange partially shown, with a sheet metal plate 52 connected or welded, which has an eyelet. The metal plate is bent by 90 ° relative to the flange and extends in the direction of the rotor blade structures. By a bolt 56 is secured with the metal plate 52 with the eyelet and the flange ring 50 a main string element 20 connected in the form of a rope or a plastic rope. This has a splice end connection 54 with a loop 53 on, in the a complete swap 55 is used. Through the full exchanges 55 and the loop 53 also runs the bolt 56 , The sheet metal plate 52 should have a sufficiently large contact surface for the complete exchanges 55 Offer.

In 25 is the anchor point according to 24 shown in cross section. The flange ring 50 , which is partially illustrated, lies on a rotor blade structure 57 , in particular the blade root-side end of the rotor blade structure 57 , on. A metal plate 52 with an eyelet is bent by 90 ° thereof. This eyelet takes a bolt 56 on, passing through an opening, namely a loop 53 with full exchanges 55 of the main rope element 22 , runs. In this way, a safe derivation of the centrifugal forces of fragments of a rotor blade structure in the blade root 2 or the flange ring 50 and the rotor hub possible.

During assembly of the rotor blade 1 Be the introduction of the main string elements 20 and the introduction of Nebenstrangelemente 21 . 22 optionally integrated into the prefabrication of the individual rotor blade components. In particular, contacting structures of the security system are secured against rattling and hitting by being laminated, over-cured or dented. In the production of the rotor blade components in the injection process, it is advantageous for this purpose to lay main and secondary strand elements on the finished laminate structure of the individual rotor blade components and then straps made of polyamide 63 or other material according to 8th . 9 . 21 . 22 at the positions of the attachment points over the strand elements.

Over the entire length of the strand elements a laminate layer should be laid. For the main string elements 20 or the main rope element 20 It is important to ensure that at the points for branching by means of node connection for secondary string elements 21 no lamination takes place over a length of about 10 to 30 cm, preferably about 20 cm. In the case of attaching rope locks to the main string elements 20 or the secondary string elements 21 . 22 The ends of the strand elements should also not be doctored or overlaminated. When laying the strand elements 20 . 21 . 22 on curved surfaces these are to be secured against slipping.

Before assembling the leaf shell halves 9 . 10 are thus already on the blade-side area, the Nebenstrangelemente 22 from the example according to 6 . 7 completely relocated and the points of contact established. The same applies separately for the laying of the side root side secondary string elements 21 as well as the laying of the main string elements 20 at the jetties 11 . 12 , The assembly of all elements or components of the security system, in particular from the blade root to the junction 40 including and thus the connection of all Nebenstrangelemente 21 . 22 to the main string elements 20 according to 6 takes place after completion of the rotor blade 1 ,

All mentioned features, including the drawings alone to be taken as well as individual features that are disclosed in combination with other features are considered alone and in combination as essential to the invention. Embodiments of the invention may be accomplished by individual features or a combination of several features.

LIST OF REFERENCE NUMBERS

1

rotor blade

2

Rotor blade root

3

Rotor blade tip

4

aerodynamic cross-sectional profile

5

Leading edge

6

Trailing edge

7

suction

8th

pressure side

9

upper half shell

10

lower half shell

11, 12

web

12a

web opening

13, 14

main belt

15, 16

front secondary belt

17, 18

rear side belt

20

Main line element

21

Secondary line element

22

Secondary line element

22 '

Loop with splice end connection

23

balancing chamber

30

anchorage point

31-32

connection points

33-36

starting points

37

Connecting point to balancing chamber

40

junction

41

baseplate

42

cable lock

43

Double threaded bolt

44

Simply threaded bolt

50

flange

51

connecting bolt

52

Sheet metal with eyelet

53

loop

54

Spleißendverbindung

55

full thimble

56

bolt

57

Rotor blade structure

60

Rotor blade structure

61

laminate layer

62

adhesive resin

63

polyamide webbing

64

laminate layer

70

Rotor blade structure in sandwich construction

71, 72

laminate layer

73

interlayer

74

About laminate

75

anchor member

76

eyelet

77

adhesive seam

78

core

79

connecting element

80

bolt

81

bolt head

82

external thread

83

mother

84, 85

washer

90-93

Fangstoßbegrenzer

94

Expansion element before impact

95

Expansion element after impact

96

anchorage point

97

rope

98

end thickening

99

outer guide body

100

inner guide body

101

webbing

102

sewing thread

103

fluid damper

104

fluid

105

stamp

106

pole

107

poetry

108

opening

109

first compartment

110

second sub-chamber

F

force

L ₀

Length before impact

L ₁

Length after impact

.DELTA.L

Length difference due to power surge

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 non-patent literature

• DIN 267-27 [0095]

Claims (15)

Safety system for a rotor blade ( 1 ) of a wind turbine, wherein the rotor blade ( 1 ) along a longitudinal extent of a rotor blade root ( 2 ) substantially to a rotor blade tip ( 3 ) and at least one region, in which the rotor blade ( 1 ) an aerodynamic cross-sectional profile ( 4 ), which has a profile leading edge ( 5 ) and a profile trailing edge ( 6 ), which via a suction side ( 7 ) and a print page ( 8th ) of the cross-sectional profile ( 4 ), wherein the security system inside the rotor blade ( 1 ) at least one at least in sections along the longitudinal extent of the rotor blade ( 1 ) arranged elongate and tensile load transmitting main strand element ( 20 ) and a plurality of elongated and tensile load transmitting Nebenstrangelementen ( 21 . 22 ), which with the at least one main strand element ( 20 ), wherein the at least one main strand element ( 20 ) with at least one stop device ( 50 ) in the area of the rotor blade root ( 2 ), the at least one main strand element ( 20 ) and / or the majority of secondary elements ( 21 . 22 ) at a plurality of connecting points ( 33 - 36 ) with planar structures of the rotor blade ( 1 ) are connected, in particular with an inner surface of the rotor blade ( 1 ), a footbridge ( 11 . 12 ) or a belt ( 13 - 17 ). Securing system according to claim 1, characterized in that secondary string elements ( 21 . 22 ) along the longitudinal extent of the at least one main strand element ( 20 ) distributed with the at least one main strand element ( 20 ) are connected. Securing system according to claim 1 or 2, characterized in that the secondary string elements ( 21 . 22 ) at least in sections transversely and / or at least in sections substantially parallel to the longitudinal axis of the rotor blade ( 1 ). Security system according to one of claims 1 to 3, characterized in that the at least one main strand element ( 20 ) and / or at least one secondary string element ( 21 . 22 ) is designed as a steel cable or as a plastic rope, wherein in particular the material used for the rope has a tensile strength of more than 500 Nmm ^-2 , in particular more than 1500 Nmm ^-2 , in particular more than 2500 Nmm ^-2 . Security system according to one of claims 1 to 4, characterized in that the at least one main strand element ( 20 ) at least in sections with a shell part ( 9 . 10 ), a footbridge ( 11 . 12 ) or a belt ( 13 - 17 ) of the rotor blade ( 1 ) connected is. Securing system according to one of claims 1 to 5, characterized in that the at least one main strand element ( 20 ) at least in sections along a zero line of a web ( 11 . 12 ) of the rotor blade ( 1 ) is arranged. Safety system according to one of claims 1 to 6, characterized in that a, in particular segmented, flange ring ( 50 ) is provided, which has at least one eye as a stop device, in particular with respect to the flange ( 50 ) is bent by 90 °. Safety system according to one of claims 1 to 7, characterized in that as a stop device a connection to the screw ( 51 ) of the sheet connection is provided. Security system according to one of claims 1 to 8, characterized in that a point of attachment ( 33 - 36 ) as an overlaminate ( 61 ) one on a planar element ( 70 ) of the rotor blade ( 1 ) main strand elements ( 20 ) or secondary string elements ( 21 . 22 ) with a piece of belt material ( 63 ), on a planar element ( 70 ) of the rotor blade ( 1 ) glued, laminated or laminated fastener ( 75 ) with a fastening eye ( 76 ) or as one or more a bridge ( 11 . 12 ) penetrating bolts ( 80 ), the one or both sides of the bridge ( 11 . 12 ) each by a metal plate ( 84 . 85 ) opposite the bridge ( 11 . 12 ) is and / or are supported and the one or more on at least one side of the bridge ( 11 . 12 ) the bridge ( 11 . 12 ) is projected or surmounted. Securing system according to one of claims 1 to 9, characterized in that a main strand element ( 20 ) or a secondary string element ( 21 . 22 ) is terminated at one end with a cable lock, with a potting, with a clamp with thimble or with a, in particular with a thimble reinforced, forming an eye splice end connection. Security system according to one of claims 1 to 10, characterized in that the compound ( 33 . 40 ) at least one secondary strand element ( 21 . 22 ) with the at least one main strand element ( 20 ) a node connection with a clamping node, which clamps in a direction tensile load, or is a splice connection. Security system according to one of claims 1 to 11, characterized in that at least one point of attachment ( 33 - 36 ) at a balancing chamber ( 23 ) of the rotor blade ( 1 ) is arranged. Security system according to one of claims 1 to 12, characterized in that components of the security system substantially to are overlaminated, hardened or over-hardened at the points where they attach to surfaces of parts of the rotor blade ( 1 ) or touching them. Rotor blade ( 1 ) a wind turbine with a safety system according to one of claims 1 to 13. Wind energy plant with a rotor blade ( 1 ) according to claim 14.

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