Wind turbine blade with tapering root bushings

Patent metadata

Field	Value
Publication number	US-9995271-B2
Application number	US-201214111027-A
Country	US
Kind code	B2
Filing date	Apr 11, 2012
Priority date	Apr 11, 2011
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

A wind turbine blade for a wind turbine is a shell structure of a fiber-reinforced composite and comprises a root region and an airfoil region. The root region has a ring-shaped cross section and comprises a plurality of elongated bushings 7 with an inner thread 22 and which are embedded interspaced in the fiber-reinforced polymer so as to substantially follow the circumference of the root region and allow access from the outside to the inner threads 22 . The bushings 7 are formed conically tapering from a second end towards a first end thereof, the first end of the bushing 7 being arranged at the end face of the root region.

First claim

The invention claimed is:

1. A wind turbine blade for a wind turbine rotor comprising a hub from which the wind turbine blade extends when mounted to the hub, the wind turbine blade including a shell structure of a fibre-reinforced composite material comprising fibres embedded in a polymer matrix, the wind turbine blade extending in longitudinal direction and having a profiled contour including a pressure side and a suction side as well as a leading edge and a trailing edge, the edges defining a chord plane therebetween, when seen in the longitudinal direction the profiled contour comprising a root region with a root end face, an airfoil region and a transition region between the root region and the airfoil region,
the root region having a ring-shaped cross section with an outer surface and an inner surface,
the root region comprising a plurality of elongated fastening members provided with fastening means, the elongated fastening members are embedded mutually spaced apart in the fibre-reinforced polymer matrix so as to substantially follow a circumference of the root region and allow access from outside to the fastening means used for mounting the blade to the hub,
the elongated fastening members comprising a first end arranged at the root end face, a second end opposite the first end, and an outer periphery comprising an outer surface, an inner surface, a first lateral face and an opposite second lateral face,

characterised in that at least a number of the plurality of elongated fastening members are formed with a longitudinally tapering section where the outer periphery is tapering in a direction from the second end towards the first end of the elongated fastening members over at least 10% of the longitudinal extent of the elongated fastening members;
wherein any cross section of the elongated fastening members is circular, perpendicular to a longitudinal axis thereof;
wherein the elongated fastening members are bushings and the fastening means is a thread in a bore in the bushing;
wherein the root region further comprises an insert separately formed of a fibre-reinforced polymer matrix and entirely arranged in regions between adjacent lateral faces of adjacent elongated fastening members, the inserts comprising a first insert part substantially corresponding to the region between the lateral faces of the adjacent elongated fastening members; and
wherein the first insert part extends at least over the entire longitudinal extent of the adjacent elongated fastening members.

2. The wind turbine blade according to claim 1 , wherein adjacent elongated fastening members are arranged so that longitudinally tapering sections of adjacent elongated fastening members face each other.

3. The wind turbine blade according to claim 1 , wherein the longitudinally tapering section of each elongated fastening member extends over the entire circumference of each elongated fastening member within the longitudinal extent of the longitudinally tapering section.

4. The wind turbine blade according to claim 1 , wherein the longitudinally tapering section extends over at least 20% of the longitudinal extent of each elongated fastening member.

5. The wind turbine blade according to claim 1 , wherein the outer periphery of the longitudinally tapering section is substantially smooth.

6. The wind turbine blade according to claim 1 , wherein the longitudinally tapering section of the at least a number of the plurality of elongated fastening members comprises oppositely arranged planar surfaces converging against each other.

7. The wind turbine blade to claim 1 , wherein the opposite lateral faces of the first insert part substantially abut the longitudinally tapering sections of the adjacent elongated fastening members.

8. The wind turbine blade to claim 1 , wherein a radially outer face of the first insert part facing towards the outer surface of the root region and a radially inner face of the first insert part facing towards the inner surface of the root region are substantially planar.

9. The wind turbine blade according to claim 1 , wherein the insert comprises metal fibres.

10. The wind turbine blade according to claim 1 , wherein metal fibres are firmly fixed to the elongated fastening members so as to extend therefrom.

11. The wind turbine blade according to claim 1 , wherein the elongated fastening members are laminated into the composite material of the root region.

12. The wind turbine blade according to claim 4 , wherein the longitudinally tapering section extends over at least 30% of the longitudinal extent of each elongated fastening member.

13. The wind turbine blade according to claim 12 , wherein the longitudinally tapering section extends over at least 40% of the longitudinal extent of each elongated fastening member.

14. The wind turbine blade according to claim 13 , wherein the longitudinally tapering section extends over at least 50% of the longitudinal extent of each elongated fastening member.

15. The wind turbine blade according to claim 14 , wherein the longitudinally tapering section extends over at least 60% of the longitudinal extent of each elongated fastening member.

16. The wind turbine blade according to claim 15 , wherein the longitudinally tapering section extends over at least 70% of the longitudinal extent of each elongated fastening member.

17. The wind turbine blade according to claim 16 , wherein the longitudinally tapering section extends over at least 80% of the longitudinal extent of each elongated fastening member.

18. The wind turbine blade according to claim 17 , wherein the longitudinally tapering section extends over at least 90% of the longitudinal extent of each elongated fastening member.

19. The wind turbine blade according to claim 18 , wherein the longitudinally tapering section extends over 100% of the longitudinal extent of each elongated fastening member.

20. The wind turbine blade according to claim 9 , wherein the metal fibres comprise steel fibres.

21. The wind turbine blade according to claim 10 , wherein metal fibres comprise steel fibres.

22. The wind turbine blade according to claim 10 , wherein the metal fibres are fixed at least to the second end of the elongated fastening members.

23. A wind turbine blade for a wind turbine rotor comprising a hub from which the wind turbine blade extends when mounted to the hub, the wind turbine blade including a shell structure of a fibre-reinforced composite material comprising fibres embedded in a polymer matrix, the wind turbine blade extending in longitudinal direction and having a profiled contour including a pressure side and a suction side as well as a leading edge and a trailing edge, the edges defining a chord plane therebetween, when seen in the longitudinal direction the profiled contour comprising a root region with a root end face, an airfoil region and a transition region between the root region and the airfoil region,
the root region having a ring-shaped cross section with an outer surface and an inner surface,
the root region comprising a plurality of elongated fastening members provided with fastening means, the elongated fastening members are embedded mutually spaced apart in the fibre-reinforced polymer matrix so as to substantially follow a circumference of the root region and allow access from outside to the fastening means used for mounting the blade to the hub,
the elongated fastening members comprising a first end arranged at the root end face, a second end

Assignees

• Dahl Martin
• Mortensen Bjarne Krab
• Hornblow Benjamin
• Lm Wp Patent Holding As

Inventors

• Dahl Martin
• Mortensen Bjarne Krab
• Hornblow Benjamin

Classifications

• F03D1/0675

  of the blades · CPC title

• Y02E10/721

  Cross-Sectional Technologies · mapped topic

• F03D1/0658 Primary

  Arrangements for fixing wind-engaging parts to a hub · CPC title

• B29C70/86 Primary

  Incorporated in coherent impregnated reinforcing layers, {e.g. by winding} · CPC title

• Y02E10/72

  Wind turbines with rotation axis in wind direction · CPC title