Method for producing a wind turbine rotor blade, and wind turbine rotor blade

A method of producing a wind turbine rotor blade. The wind turbine rotor blade has at least an inner blade portion and an outer blade portion, as well as a connecting element. The inner blade portion is wound on a winding form having a first and a second winding portion. The first and second winding portions are releasably fixed to each other by way of a screw connection. The second winding portion is of a conical configuration so that after winding of the inner blade portion a sleeve is produced at an end of the inner blade portion.

BACKGROUND

Technical Field

The present invention concerns a method of producing a wind turbine rotor blade and a wind turbine rotor blade.

Description of the Related Art

US 2007/0253824 A1 discloses a modular rotor blade of a wind turbine. The rotor blade is of a two-part configuration and has an inner blade portion and an outer blade portion. The inner blade portion and the outer blade portion can be fixed to each other or fixed together by means of a connecting element. Transport of the rotor blade can be considerably simplified by virtue of the multi-part structure of the rotor blade. The connection between the inner blade portion and the outer blade portion is effected by vacuum infusion. Vacuum infusion at that location however is difficult and time-consuming.

On the German patent application from which priority is claimed the German Patent and Trade Mark Office searched the following documents: US 2007/0253825 A1, DE 32 39 804 A1, DE 10 2008 055 513 B4 and US 2014/0169978 A1.

BRIEF SUMMARY

Provided is a wind turbine rotor blade which is of a multi-part configuration and which has an improved connection between the respective parts.

Provided is a method of producing a wind turbine rotor blade. The wind turbine rotor blade has at least an inner blade portion and an outer blade portion, as well as a connecting element. The inner blade portion is wound on a winding form having a first and a second winding portion. The first and second winding portions are releasably fixed to each other by way of a screw connection. The second winding portion is of a conical configuration so that after winding of the inner blade portion a sleeve is produced at an end of the inner blade portion.

According to an aspect of the present invention the connecting element is wound on a winding form. The connecting element has a first and a second portion.

According to a further aspect of the present invention a form having a conical internal shape is pushed on to the first portion of the connecting element before the winding laminate is hardened in order to provide a first portion of a conical configuration and having a smooth surface.

According to a further aspect of the present invention the at least one inner blade portion and the at least one outer blade portion are releasably connected together or adhesively bonded together by way of the connecting element.

Provided is a wind turbine rotor blade comprising an inner blade portion, an outer blade portion, and a connecting element for connecting the inner blade portion and the outer blade portion. The inner blade portion has a sleeve at a first end, which is achieved by winding of the inner blade portion. The at least one inner blade portion and at least one outer blade portion can be fixed together by way of a screw connection so that the inner blade portion is fixed to the outer blade portion by way of the connecting element.

In a further aspect of the present invention the inner blade portion can have at least one first web which is glued thereto. The connecting element is introduced into the sleeves of the inner blade portion with its first end which has a second web glued therein. The second end of the connecting element can be glued in an end of the outer blade portion.

The wind turbine rotor blade is at least of a two-part configuration and has an inner blade portion and an outer blade portion. The inner blade portion has for example the rotor blade root and is secured to a hub of the wind turbine. At an opposite end the inner blade portion has a receiving unit or sleeve into which a connecting element can be partially introduced. The rotor blade further has an outer blade portion which can be fixed to the inner blade portion by means of the connecting element.

The wind turbine rotor blade makes it is possible to avoid complicated and laborious milling operations at both sides of the blade separation junction. In addition complicated and expensive flange laminates can be avoided in the region of the outer blade.

According to an aspect of the present invention the blade separation junction can also be displaced outwardly. That makes it possible to better divide up the units for transport. Furthermore inexpensive inner blade production can be expanded by virtue of the winding laminate. In addition quicker assembly can be made possible on the building site. Finally, it is also possible to avoid a thickening of the profile configuration, as in the case of a classic transverse bolt connection.

According to an aspect of the present invention a contact plane between the sleeve of the inner blade portion and the push-in member (connecting element) is of a conical configuration involving a given angle in order to permit clean assembly and separation of the connection. A gap can be defined by virtue thereof between the inner blade and the outer blade. That concerns the position of the blade parts in the longitudinal direction after being fitted together and braced in position. Furthermore the cross-section of the contact plane can be not round but for example elliptical in order also to be able to better transmit torsional loads without having to rely only on frictional forces. Furthermore the contact plane can be of such a configuration that only two regions are in contact at the beginning and at the end in the longitudinal direction. That can provide for load transfer in a more defined and more predictable fashion. The regions of high accuracy are reduced and the clamping action by virtue of the biasing effect is enhanced. By virtue of the precise shaping of the sleeve by virtue of a precisely manufactured winding form it is possible to provide that the surfaces are of the desired shape without having to be subsequently milled.

The precise shaping of the push-in member (connecting element) can be achieved by a precisely produced negative form which is pushed on to the winding laminate which has been freshly wound and has not yet hardened without having to mill the surface after hardening to impart the desired shape.

Further configurations of the invention are subject-matter of the appendant claims.

DETAILED DESCRIPTION

FIG. 1shows a diagrammatic view of a wind turbine. The wind turbine100has a tower102and a pod104. A rotor106having three rotor blades200and a spinner110is provided on the pod104. The rotor106is driven in rotation in operation by the wind and drives a generator in the pod104to generate electric energy.

The rotor blade200has at least two parts, namely an inner blade portion210and an outer blade portion220. The outer blade portion220is fixed to the inner blade portion210.

FIG. 2shows a diagrammatic sectional view of an inner blade portion during manufacture thereof. The inner blade portion210is wound. For that purpose there is provided a winding core with a first winding form310and a second winding form320which are fixed to each other or connected together by way of an interface330. The first winding form portion310is supported by way of a bearing340aand the second winding form portion320is supported by way of a further bearing340bso that the winding core can rotate.

The first winding portion320has a first end311and a second end312. The first end311is coupled to the bearing340a. The second end312is coupled by way of the connecting interface330to a first end321of the second winding portion320. By way of example the first and second winding portions310,320can be releasably fixed to each other by way of a screw connection. Optionally the diameter of the first winding portion310can decrease from the first end311to the second end312. The diameter of the second winding portion320can increase from the first end321to the second end322. Thus the winding core can be of the smallest diameter in the region of the interface330. That configuration of the winding core can provide that an inner blade portion with an undercut configuration213can be produced.

Fiber composite fabrics are wound on to the winding form310,320. After the inner blade portion210has been produced the screw connection in the region of the interface330can be released and the first and second winding portions310,320can be separated out so that only the inner blade portion210in particular with the undercut configuration213remains. The inner blade portion210has a first end211and a second end212. A thickening of the winding material or a flange thickening for a transverse bolt connection (for example in relation to the rotor hub) can be provided in the region of the first end211.

The second winding portion320can be provided in the form of a sleeve shape in order to provide a sleeve in the region of the second end212of the inner blade portion. That sleeve serves in particular to receive an end of the connecting element.

According to an aspect of the present invention the first and second winding portions310,320can be made from a metal like for example steel. That is particularly advantageous because it is possible in that way to provide a smooth surface on the first and second winding portions310,320. In particular the smooth surface of the first and/or second winding portion320can provide a smooth inside surface215,216and in particular a sleeve portion in the region of the second end212of the inner blade portion which is also smooth.

FIG. 3shows a diagrammatic sectional view of a connecting element upon manufacture thereof. A winding form700is provided for producing a connecting element600which for example can be in the form of a connecting beam. The winding form700has a first and a second end701,702as well as a transitional portion703. The outside diameter of the winding form700is increased in the region between the transition of the first end701and the transitional region703. Fiber-darkening material can be wound on to the winding form700which is supported for example by means of bearing710on a foundation400by rotation of the winding form700in the material.

The connecting element600has a first end611and a second end621. In addition the connecting element600has a first portion610in the region of the first end611and a second portion620in the region of the second portion610,620. A central portion630is provided between those two portions610,620.

In order to achieve a smooth surface for the first portion610a steel form500can be provided for example on wheels520. The steel form500is of an inside diameter510which narrows to a closed end530. After the winding element600has been wound and before the material has hardened the steel form500is pushed on to the first end610so that the insides of the steel form bear against the first portion610. In that way the outer region of the first portion610can be produced as being very smooth.

FIG. 4shows a diagrammatic sectional view of a connecting element during manufacture thereof.FIG. 4shows how the steel form500has been pushed on to the first portion610of the connecting element600while the winding material of the connecting element600is still on the winding form700.

FIG. 5shows a diagrammatic sectional view of a part of a wind turbine rotor blade.FIG. 5shows in particular a blade separation junction between the inner blade portion210and the outer blade portion220. The connection between the inner blade portion210and the outer blade portion220is made by way of the connecting unit600. The connecting unit600has a first portion610which has been produced as described with reference toFIGS. 3 and 4and preferably has a smooth surface. The first portion610is introduced into the sleeve212of the inner blade portion210.

The connecting element600can have a web650which is glued therein. A further web250can be glued in place in the region of the thickening portion or the undercut configuration213. The two webs650,250can be screwed together or fixed to each other by means of a transverse bolt260. The second portion620of the connecting unit is pushed into an open end of the outer blade220and preferably glued by means of an adhesive810.

In optimum fashion an anti-friction coating660can be provided in the region of the sleeve. The first end of the connecting element can thus be pushed into the sleeve portion212and fixed by means of the webs250,650and the transverse bolt260.

That makes it possible to achieve a reversible fixing option between the inner blade portion and the outer blade portion.

FIG. 6shows a diagrammatic sectional view of an inner blade portion during manufacture thereof.FIG. 6shows an alternative winding form340in relation to the winding form shown inFIG. 2. While the winding form inFIG. 2comprises steel, the winding form340inFIG. 6comprises for example a fiber composite material. The winding form340does not have to be removed from the inner blade portion but can remain therein. Accordingly the winding form340represents a lost winding form because it remains in the inner blade portion.

The winding form340has a first end341and a second end342as well as a steel connection344, by way of which the winding form is connected to a bearing340a. The bearing340acan be provided on a foundation400. The winding form340can for example have a plurality of transverse stiffening members343. By virtue of the fact that the winding form340does not have to be removed from the blade portion the first end211of the inner blade portion210can be wider so that a flange thickening configuration for example for making transverse bolt connections can be provided. The material of the inner blade portion210can be wound on to the winding form340. The winding form340can be coupled to a second winding form320for example by way of a screw connection. In that case that second winding form320corresponds to the winding form320shown inFIG. 2. That winding form is intended in particular to produce a sleeve shape for the inner blade. After the inner blade portion210has been produced the second sleeve form320can be removed by releasing the screw connections. Optionally the steel connection344can remain in the winding form340or removed.

FIG. 7shows a diagrammatic sectional view of an inner blade portion during manufacture thereof.FIG. 7shows in particular how the material is wound on to the winding form310,320. Optionally the winding form310can have studs310aand the second winding form320can have studs310b. Therefore, a winding laminate can be applied to the winding form.

After a first layer of winding laminate has been applied to the winding form at least one layer of unidirectional (UD) rovings can be applied. In that case the rovings can be applied around the studs310a,310b.

Optionally the outside of the first winding laminate layer can be of a substantially straight configuration so that the unidirectional UD rovings can be simply placed thereon.

FIG. 9shows a diagrammatic sectional view of an inner blade portion during manufacture thereof.

FIG. 10shows a diagrammatic sectional view of the connecting element during manufacture thereof.

FIGS. 10 to 12show in particular the production of the connecting element600. A first layer of winding laminate FKV1is applied to the winding form700so that a straight line is provided at the outside. Unidirectional UD rovings can be provided thereon by means of the rovings. In particular the rovings can be wound around the studs700a,700b. A second layer of winding laminate FKV can then be applied.