ELASTIC ROTARY BEARING FOR TWO-BLADE ROTORS OF WIND TURBINES

Abstract

The invention relates to an elastic rotary bearing for two-blade rotors that are used in wind turbines for high load cycles. The invention relates in particular to a new type of rotor hub for, in particular, elastically mounted two-blade rotors of wind turbines into which an elastic rotary bearing is integrated, which in turn is composed of two rotational joint units composed of layer elements and cone elements.

Claims

1. A rotary bearing for high load cycles as an integral constituent part of a rotor hub for an elastically mounted two-blade rotor of a wind turbine, which rotor is capable of performing a pendulum motion by an angle of rotation of at least 3 when under the action of simultaneously high axial and radial forces, comprising a first, inner component (3), which is firmly connected to the rotor shaft (1) and thus to the rotating structure of the wind turbine, and a second, outer movable component (2), which has connection regions (7) for two opposing rotor blades (7a, 7b), the first, rigidly connected inner component (3) and the second, movable outer component (2) being connected to one another via rotational joint units (5) in such a way that under the action of force the rotor blades (7a, 7b) connected to the rotor hub can be reversibly moved toward or away from the structure of the wind turbine, wherein (i) at least two rotational joint units (5) are arranged opposite one another and are firmly connected to one another, and each rotational joint unit is substantially composed of (a) at least one conical bushing (5.1), which in each case comprises a plurality of elastic layers (18) for absorbing forces acting predominantly radially with respect to the cone axis and has a taper angle (5.1.4) which is selected such that the torsional load occurring during operation is minimized, the at least one conical bushing (5.1) of the first rotational joint unit (5) being firmly connected to the at least one conical bushing (5.1) of the second rotational joint unit (5) via a bolt-like connection (6), and (b) at least one elastic layer spring (5.2), which is arranged such that it has a common axis with the at least one conical bushing and absorbs those axially acting forces which cannot be absorbed by the conical bushing, (ii) the first, inner component (3), which is firmly connected to the rotor shaft (1), is firmly connected on two opposite sides to the innermost layer of the conical bushing (5.1) of each rotational joint unit (5), the cone axes being perpendicular to the axis of the rotor shaft (1), and (iii) the second, outer, movable component (2) is firmly connected to the outermost layer of the at least one conical bushing (5.1) of each rotational joint unit (5), so that under the action of force a reversible torsional deformation of the individual elastic layers (18) of the conical bushings (5.1) and possibly a torsional deformation of the particular layer springs (5.2) takes place, as a result of which said pendulum motion of the two-blade rotor is made possible.

2. The rotary bearing according to claim 1, wherein the taper angle (5.1.4) of the particular conical bushings (5) is less than 20, in particular less than 15, preferably 8-12.

3. The rotary bearing according to claim 1, wherein the at least one conical bushing (5.1) has six to ten layers (18), which are separated from one another by inelastic elements.

4. The rotary bearing according claim 1, wherein the at least one axially acting elastic layer spring (5.2) is composed of 3-8 elastic layers which are separated from one another by inelastic elements.

5. The rotary bearing according to claim 1, wherein the at least one elastic axial layer spring (5.2) is a flat sandwich element (5.2.1) which forms a structural unit with a radially acting conical bushing (5.1) of a rotational joint unit (5).

6. The rotary bearing according to claim 1, wherein the at least one elastic axial layer spring (5.2) is formed by at least one axially acting hemispherical element (5.2.2).

7. The rotary bearing according to claim 6, wherein two hemispherical elements (5.2.2) axially opposite one another with a spacing (9.1), together with the corresponding radially acting conical bushing (5.1), form a rotational joint unit (5), the hemispherical elements being connected to one another by a correspondingly shaped solid core (9.2).

8. The rotary bearing according to claim 1, wherein the first, inner, rigid component (3) is connected to the innermost layer of said conical bushings of said rotational joint units (5) via the bolt-like connections (6) correspondingly shaped in the region of the conical bushings (5.1).

9. The rotary bearing according to claim 1, wherein the conical bushings (5.1) are removable and replaceable.

10. The rotary bearing according to claim 9, wherein the conical bushings (5.1) have in their interior correspondingly shaped loose conical elements (5.1.5) which have means for guiding (5.1.6) and bracing (5.1.7).

11. The rotary bearing according to claim 1, wherein the outer elastic layers (18) of the conical bushing (5.1) have a lower Shore hardness than the inner elastic layers (18).

12. The rotary bearing according to claim 11, wherein the Shore hardness of the layers (18) increases from the outside to the inside by 2-5% per layer.

13. The rotary bearing according to claim 1, wherein the inner elastic layers (18) of the conical bushing (5.1) have a greater thickness than the outer elastic layers (18).

14. The rotary bearing according to claim 13, wherein the thickness of the layers (18) decreases from the inside to the outside by 5-10% per layer.

15. The rotary bearing according to claim 1, wherein the outer layers (18) of the conical bushing (5.1) are shorter than the inner layers.

16. The rotary bearing according to claim 1, wherein the rotational joint units (5) have a plurality of stop elements (4) which are designed and arranged such that they limit the pendulum motion of the rotor blades (7a, 7b).

17. A rotor hub for a two-blade rotor, wherein it has a rotary bearing according to claim 1.

18. A wind turbine comprising substantially a tower, a generator and a two-blade rotor capable of pendulum motion, wherein the two-blade rotor has a rotor hub according to claim 17.

Description

[0046] The invention is described in more detail below with reference to drawings.

[0047] FIG. 1 shows a typical rotor hub according to the invention in perspective view.

[0048] A rotor shaft (1) is firmly connected to a fixed component, in the example shown in the form of a carrier plate (3). The carrier plate (3) thus rotates with the rotor shaft. The carrier plate (3) is connected to two opposing joint units (5) (only one is shown). Furthermore, the joint units are connected to a component (2) which can move relative to the rotor axis and is designed in such a way that it accommodates in its interior the carrier plate (3) and the end piece of the rotor shaft. The component (2), which forms the outer shape of the rotor hub, is movably fastened to the joint units (5) and, when force acts on the rotor blades, executes the desired rotational movements toward the structure of the wind turbine. The rotor blades of the two-blade rotor (not shown) are attached to the connecting pieces (7) of the movable component (2). The component (2), which can move only about the axis of rotation, together with the two rotor blades, is limited in its movement relative to the fixed component (3) by elastic stop devices (4) inside said component.

[0049] FIG. 2 shows the rotary bearing according to the invention, or rotor hub, analogously to FIG. 1, with more details in a side view (a) and again in a perspective view (b). FIG. 2 shows in particular the arrangement and design of the two opposing joint units (5) on the carrier plate (3). Each joint unit (5) consists of a conical bushing (5.1) and a layer-spring element (5.2). The conical bushings (5.1) are arranged so that their wide base points inward and their narrow base points outward, with the cone axis being identical to the longitudinal axis of the carrier plate (3). A flat layer-spring element (5.2) is arranged in each case outwardly above the narrow cone base and can thus absorb and transmit the axial forces. The carrier plate (3) and the joint elements (5.1) (5.2) are connected via pins or bolts (6) which are shaped according to the cone shape and are attached as an extension of the carrier plate (3). The pins (6) of the fixed carrier plate (3) are connected to the inner surface of the conical bushing (5.1), whereas the outer surface of the conical bushing is connected to the movable part (2), so that rotation of the components (2) and (3) relative to one another, and thus of the rotor blades relative to the structure, is made possible by reversible torsional deformation of the elastic conical bushings. Stop devices (4) are provided between the components (2) and (3) and limit the one-dimensional movement of the rotor blades (not shown) attached to the component (2).

[0050] FIG. 3 (a) shows a perspective view of a rotor shaft (1) with the firmly connected carrier plate (3). The carrier plate (3) is in turn connected to the two joint units (5), specifically in such a way that the inner elastic cone surface is connected in each case via the connection pins (6) shown in FIG. 2 (not shown here). For reasons of better clarity, the movable part (2), which is connected to the particular outer cone surfaces of the two conical bushings (5.1), is not shown. The figure also shows three of four pairs of stop devices (4) for the movable part (2) and their arrangement on the carrier plate (3).

[0051] FIG. 3b shows a top view of the carrier plate (3) with two opposing joint units (5) according to the invention and how they are fastened; again, the movable component (2) has been omitted for the sake of clarity.

[0052] FIG. 4 shows a detailed representation of a joint unit (5) according to the invention in perspective view (a) and as a side view (b) (c).

[0053] A multi-layered cone element (5.1) with a taper angle (5.1.4) firmly encloses with its inner surface a pin or bolt (6) correspondingly shaped in this region, which in turn is firmly connected to the carrier plate (3) shown below.

[0054] Alternatively, however, as shown in FIG. 4 (c), the conical bushing can also be firmly but detachably connected to the pin (6) by means of a clamping screw (5.1.7) via a correspondingly shaped removable cone element (5.1.5), thus allowing easy replacement of the bushing and the pin. The removable cone element (5.1.5) rests in a circular guide (recess) (5.1.6).

[0055] Above the conical bushing, a layer-spring element (5.2) is arranged as a multi-layered sandwich element (5.2.1) such that the axes of the two components are identical. The axially acting layer-spring element (5.2) and the conical bushing (5.1) are surrounded by a housing (5.3). The housing (5.3) is firmly connected on the inside to the outer surface of the conical bushing (5.1) and on the outside to the movable component (2).

[0056] Thus, an elastic torsional/rotational movement of the movable part (2) relative to the fixed part (3) can take place on the cone under the action of force; this is equivalent to a rotational movement of the two-blade rotor relative to the axis of the rotor shaft toward the rotating structure of the wind turbine. FIG. 4 also shows the other essential geometric dimensions (5.1.1)(5.1.2)(5.1.3) of the conical bushings used for optimum effect.

[0057] FIG. 5 (a)(b) shows a further embodiment of the invention.

[0058] In contrast to the representation according to FIG. 4, the flat sandwich element (5.2) is replaced by two axially opposite hemispherical shells (5.2.2), which are connected to one another other via a correspondingly shaped core or bolt (9.2). The distance between the hemisphere pivot points is given by the position (9.1).

[0059] This arrangement allows additional axial and radial displacement of the elastic components.

[0060] FIG. 6. shows in detail a conical bushing (5.1) as a constituent part of the rotary bearing according to the invention in side view as it is used in an optimized embodiment of the invention. The conical bushing consists of eight elastic layers (18) (a-h), which are separated from one another by firmly connected metal sheets. In principle, bushings with 6-10 layers are also suitable. The thickness of each layer decreases from layer to layer from the inside to the outside. The innermost layer a thus has the greatest thickness (16), while the outermost layer h has the smallest thickness (17). Furthermore, the cone length (14) of the innermost layer a is greater than the subsequent layer b, which in turn is greater than the outermost layer c, etc. The innermost layer a can thus have a length (14) up to 30% greater than the length (15) of the outermost layer h.

[0061] In a particular embodiment of such conical bushings, the different layers (18) also have different Shore hardnesses, the Shore hardness of the layers (18) increasing from the outside to the inside by 2-5% per layer. Such bushings exhibit optimal properties with regard to radial and torsional deformation of the individual elastic layers. The conical bushing (5.1) is further characterized by the stated smaller and larger, inner and outer diameters (10)(11)(12)(13).