Pitch system for a wind turbine blade

Patent metadata

Field	Value
Publication number	US-12270371-B2
Application number	US-202218565156-A
Country	US
Kind code	B2
Filing date	Jun 8, 2022
Priority date	Jun 23, 2021
Publication date	Apr 8, 2025
Grant date	Apr 8, 2025

Abstract

A pitch actuator for a wind turbine pitch system, the pitch actuator having an actuator rod, a drive end of which is defined by a clevis fork arrangement having first fork member and a second fork member that extend in a direction along a rod axis and terminate at a tip end. The first and second fork members define respective clevis openings for receiving a clevis pin therethrough, said clevis openings each having an opening perimeter profile comprising: a first perimeter section defined by a leading circular arc that is centred on the rod axis and oriented in the direction of the tip end of the fork members, the circular arc defining a nominal radius and a central angle of less than 120 degrees, and second and third flared perimeter sections that flank respective sides of the first perimeter section, each of which define an enlarged clearance zone with respect to at least part of an imaginary circle defined by the nominal radius of the first perimeter section. A benefit of the invention is that the enlarged clearance zones defined by the flared perimeter sections create an area where there is no contact between the perimeter of the openings and the outer surface of the clevis pin. This provides a stress relieving function since deformation of the openings in use, due to force applied along the axis of the actuator rod, does not create a point of stress combined with sliding or rubbing movement with the sides of the clevis pin, thereby reducing wear and fatigue. The invention extends to a pitch system including such a pitch actuator and a wind turbine incorporating such a pitch system.

First claim

The invention claimed is:

1. A pitch actuator for a wind turbine pitch system, the pitch actuator having an actuator body and an actuator rod movable within the actuator body, the actuator rod including a drive end that is defined by a clevis fork arrangement having first fork member and a second fork member that extend in a direction along a rod axis (L) of the actuator rod and terminate at a tip end, wherein the first and the second fork members define respective clevis openings for receiving a clevis pin therethrough, said clevis openings each having an opening perimeter profile comprising:
a first perimeter section defined by a leading circular arc that is centered on the rod axis and oriented in the direction of the tip end of the fork members, the leading circular arc defining a nominal radius (R) and a central angle of less than 120 degrees, and
second and third flared perimeter sections that flank respective sides of the first perimeter section, each of which define an enlarged clearance zone with respect to at least part of a circle defined by the nominal radius of the first perimeter section.

2. The pitch actuator of claim 1 , wherein the second and third flared perimeter sections each define at least a linear portion.

3. The pitch actuator of claim 1 , wherein the second and third flared perimeter sections each define at least a curved portion that has a radius less than that of the nominal radius.

4. The pitch actuator of claim 1 , wherein the opening perimeter profile further comprises a fourth perimeter section defined by a trailing circular arc that is centered on the rod axis, and which is flanked by the second and third flared perimeter sections.

5. The pitch actuator of claim 4 , wherein the fourth perimeter section defines a radius that matches the nominal radius of the first perimeter section.

6. The pitch actuator of claim 4 , wherein the fourth perimeter section has a central angle of less than 120 degrees.

7. The pitch actuator of claim 1 , wherein each of the first and second fork members has a width dimension, perpendicular to the rod axis, wherein that width dimension is substantially uniform along the length of the first and second fork members along the rod axis.

8. The pitch actuator of claim 1 , wherein each of the first and second fork members has a depth dimension, perpendicular to the rod axis, and wherein the depth dimension is non-uniform along the length of each fork member along the rod axis.

9. The pitch actuator of claim 8 , wherein each of the first and second fork members has a radially inner portion and a radially outer portion, wherein the depth dimension of the radially outer portion is less than the depth dimension of the radially inner portion.

10. The pitch actuator of claim 9 , wherein the depth dimension of the radially inner portion is the same or less than a depth dimension of an adjacent portion of the actuator rod.

11. The pitch actuator of claim 1 , wherein the drive end is configured to be removably attached to the actuator rod.

12. A pitch system for rotating a blade of a wind turbine relative to a hub, the pitch system comprising:
a blade bearing including an inner bearing ring and an outer bearing ring, wherein the outer bearing ring is rotatable relative to the inner bearing ring,
an actuator system configured to control relative rotational movement between the inner bearing ring and outer bearing ring, comprising:
a pitch actuator in accordance with claim 1 , wherein the actuator rod of the pitch actuator is coupled to one of the inner bearing ring or the outer bearing ring at a connection bracket,

wherein the connection bracket comprises a blade member received between the first and second fork members of the actuator rod, and which defines a clevis opening which is aligned with the respective openings provided in the first and second fork members, and
wherein a clevis pin extends through the respective clevis openings of the first and second fork members and the blade member.

13. The pitch system of claim 12 , wherein the clevis opening of the blade member comprises a bearing that provides at least a rotational degree of freedom of the clevis pin received therethrough.

14. The pitch system of claim 13 , wherein the bearing is a spherical bearing.

15. The pitch system of claim 12 , wherein the clevis pin has a cross-sectional outer profile that is generally circular with a radius substantially equal to the radius of the circular arc defined by the first perimeter section.

16. The pitch system of claim 15 , wherein the clevis pin defines first and second opposed longitudinally-extending facets, and wherein the clevis pin is oriented in the respective clevis openings such that the first and second opposed longitudinally-extending facets are aligned with the rod axis.

17. A wind turbine comprising a pitch system as claimed in claim 12 .

18. The pitch actuator of claim 1 , wherein the second and the third flared perimeter sections do not contact the clevis pin.

Assignees

• Vestas Wind Sys As

Inventors

• Andersen Lasse Godballe
• Garde Erik

Classifications

• F05B2270/60

  Control system actuates through · CPC title

• F05B2260/507

  using servos, independent actuators, etc. · CPC title

• F03D7/0224 Primary

  Adjusting blade pitch · CPC title

• Y02E10/72

  Wind turbines with rotation axis in wind direction · CPC title

• F05B2260/79

  Bearing, support or actuation arrangements therefor · CPC title