Gear Unified Pitch Drive Mechanism

In the section of the individual blade pitch system of the wind turbine, the independent electric pitch system is introduced. In the section of the uniform pitch drive mechanism of the drive rod, the composition and principle of the drive rod pitch mechanism are introduced. In this section, a uniform pitch drive mechanism using gears is introduced.

Figure 1 is a schematic view of the front and back sides of the pitch bearing. The outer ring of the pitch bearing is fixed on the hub. In order to strengthen the difference, it is dyed yellow, and the outer ring of the pitch bearing is cut open. There are multiple steel balls between the inner ring and the outer ring of the bearing, and the outer ring and the inner ring constitute a rolling bearing. A blade mounting flange is fixed on the side of the inner ring of the pitch bearing for mounting the blade, and the blade is mounted to rotate freely on the side of the outer ring of the pitch bearing. The pitch bearing is designed with four-point contact ball bearing and can withstand loads in multiple directions.

Pitch bearing and blade mounting flange
Figure 1--Pitch bearing and blade mounting flange
The entire blade is very long, for the sake of simplicity, a section of the middle section of the blade representing the entire blade, called a blade. The blade is mounted on the blade mounting flange by bolts at the root of the blade (the blade is directly attached to the flange in the figure), and the blade mounting flange is coaxially fixed with the pitch angle bevel gear, when the pitch angle bevel gear rotates, the blades rotate synchronously. The left diagram of figure 2 is the position where the pitch angle is 15, and the right diagram of figure 2 is the position where the pitch angle is 90 degrees.
pitch bevel gears and blades
Figure 2 - pitch bevel gears and blades
The outer ring of the pitch bearing is mounted on the outer ring mounting hole of the pitch bearing of the hub (center alignment). See figure 3. In order to see the internal structure, the hub in the figure is cut by 1/3.
pitch bevel gear and hub
Figure 3 - pitch bevel gear and hub
The pitch angle bevel gear and the pitch drive bevel gear form a gear transmission, the two gear axis intersect and are perpendicular, and the pitch drive bevel gear rotates to drive the pitch angle bevel gear to rotate, as shown in figure 4.
Transmission of pitch bevel gear
Figure 4 - Transmission of pitch bevel gear

The other end of the rotating shaft of the pitch driving bevel gear is fixedly equipped with a pitch driving worm gear, the pitch driving worm meshes with the worm gear engagement, and the pitch driving worm is driven by the pitch driving motor (including the speed reducer). Controlling the rotation and rotation direction of the pitch drive motor can change the rotation and rotation direction of the pitch drive bevel gear, as shown in figure 5. Note: For the sake of simplicity and clarity, the support members of the respective rotating shafts are not shown in the figure, and the support members of the respective rotating shafts are also not shown in the drawings of the course.

Worm gear and pitch bevel gear
Figure 5 - Worm gear and pitch bevel gear
In figure 6, a bevel gear pitching mechanism having three pitch angle bevel gears and a hub is shown. To avoid mutual occlusion, the other two blade mounting flanges are not shown.
Bevel gear pitch mechanism
Figure 6 - Bevel gear pitch mechanism
The arrangement of the main parts of the gear unitary pitch drive mechanism is viewed from another angle in figure 7, and an animation is used to demonstrate the movement of the components from this angle.
Animal screenshot of the bevel gear pitch mechanism
Figure 7--Animal screenshot of the bevel gear pitch mechanism
Let's watch this animation below, which demonstrates the state of the wind turbine pitch.
Gear unified pitch drive mechanism animation
Gear unified pitch drive mechanism has a simple structure, convenient and reliable operation, and is widely used in small and medium-sized wind power generators.
 

 
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