Wind turbine blade
View Patent ↗A wind turbine blade comprising an aerodynamic fairing supported along at least a portion of its axial length by a spar ( 12 ). The spar comprises at least two spar segments ( 12 ) joined end-to-end at an interface ( 9 ), each spar segment comprising a shear web ( 3 ) with a spar cap ( 4 ) on each side. The outer face ( 6 ) of each spar cap tapers inwardly towards the interface such that its depth is reduced towards the interface creating a recess on each side of the interface formed by the tapered faces of adjacent spar caps. A respective connection piece ( 8 ) is sized to fit into each recess. Each connection piece ( 8 ) is sized to fit into each recess. Each connection piece ( 8 ) being fixed to the tapered faces of adjacent spar caps to form a double scarf joint.
1. A wind turbine blade comprising an aerodynamic fairing supported along at least a portion of its axial length by a spar, the spar comprising at least two spar segments joined end-to-end at an interface, each spar segment comprising a shear web with a spar cap on each side; wherein the outer face of each spar cap tapers inwardly towards the interface such that its depth is reduced towards the interface creating a recess on each side of the interface formed by the tapered faces of adjacent spar caps; and a respective connection piece sized to fit into each recess, each connection piece being fixed to the tapered faces of adjacent spar caps to form a double scarf joint.
2. A blade according to claim 1 , wherein the end of each shear web is substantially perpendicular to the axial direction such that the ends of the shear webs support one another.
3. A blade according to claim 1 , wherein there is no double scarf joint between the shear webs.
4. A blade according to claim 1 , wherein the connection piece is bonded to the tapered faces of adjacent spar caps.
5. A blade according to claim 4 , wherein the connection piece is a pre-cured component.
6. A blade according to claim 1 , wherein the connection piece is formed in situ from a plurality of laminations.
7. A blade according to claim 1 , wherein the shear webs of adjacent spar segments are connected together.
8. A blade according to claim 7 , wherein the shear webs of adjacent spar segments are bonded together with adhesive.
9. A blade according to claim 1 , further comprising a support member which receives and aligns the shear webs relatively to one another.
10. A blade according to claim 6 , wherein adjacent spar segments are bonded together with adhesive that is applied to the support member.
11. A method of making a blade according to claim 1 comprising the steps of inserting spar caps of adjacent segments into a U-shaped channel with their tapered surface uppermost; and fitting the connection piece to the tapered surfaces of the adjacent spar caps.
12. A method according to claim 11 , further comprising subsequently joining additional spar caps with additional connection pieces to the subassembly formed by the method of claim 11 .
13. A method according to claim 12 , further comprising repeating the steps of claim 12 to form a second spar cap, joining the two spar caps with at least one shear web to form a first spar beam.
14. A method according to claim 13 , further comprising repeating the steps of claim 11 to form a second spar beam and joining the first and second beams side by side to form a spar.
15. A method according to claim 11 , where the U-shaped channel is the channel used to form the spar caps.