Description
Technical Parameters
Pitch Bearing Seal
|
property
|
unit
|
test method
|
test parameter
|
value
|
|
hardness
|
Shore A
|
ASTM D 2240
|
77 +3/-2
|
|
|
specific gravity
|
g/cm3
|
ASTM D 297
|
2,10±0.03
|
|
|
tensile strength
|
MPa
|
ASTM D 412
|
14,2
|
|
|
ultimate elongation
|
%
|
ASTM D 412
|
152
|
|
|
compression set
|
%
|
ASTM D 395 B
|
22h / 200°C
|
16
|
|
low temp. resistance
|
°C
|
ASTM D 2137 A
|
Brittleness no cracks
after 3 min. at
|
-15
|
|
low temp. resistance
|
°C
|
ASTM D 1329
|
TR10
|
-16
|
what is Pitch Bearing Seal
1
Pitch bearing seals serve a dual purpose: they protect internal components from contamination and prevent lubricants from escaping into the environment.
2
A common pitch bearing seal is hydrogenated nitrile butadiene rubber (HNBR), which fits into a groove in one race, with two sealing lips dragging along opposite races.
3
Improves turbine reliability and reduces operating and maintenance costs even in harsh environments.
Causes of grease leakage from pitch bearing seal
1. Aging and wear of sealing rings
Most pitch bearings use nitrile rubber sealing rings, which will age after long-term use. The aging rate is related to factors such as the acrylonitrile content in nitrile rubber, antioxidants, and the use environment. The pitch bearing adopts a contact seal. During operation, the sealing ring is in contact with the seal friction surface. The sealing ring will gradually wear, resulting in a decrease in sealing performance and insufficient pressure bearing of the sealing ring. Grease may escape from the sealing ring.
Most pitch bearings use nitrile rubber sealing rings, which will age after long-term use. The aging rate is related to factors such as the acrylonitrile content in nitrile rubber, antioxidants, and the use environment. The pitch bearing adopts a contact seal. During operation, the sealing ring is in contact with the seal friction surface. The sealing ring will gradually wear, resulting in a decrease in sealing performance and insufficient pressure bearing of the sealing ring. Grease may escape from the sealing ring.
2. Unreasonable structural design
Pitch bearings generally use double-lip seals. The outer lip can prevent moisture, dust, and other harmful substances from invading the inside of the bearing, and the inner lip can prevent grease leakage. If the structural design of the sealing ring is unreasonable, the sealing effect will be affected after installation, and the sealing ring may be deformed after the pitch bearing is operated, resulting in insufficient sealing capacity or sealing failure, and the grease is prone to leakage.
Pitch bearings generally use double-lip seals. The outer lip can prevent moisture, dust, and other harmful substances from invading the inside of the bearing, and the inner lip can prevent grease leakage. If the structural design of the sealing ring is unreasonable, the sealing effect will be affected after installation, and the sealing ring may be deformed after the pitch bearing is operated, resulting in insufficient sealing capacity or sealing failure, and the grease is prone to leakage.
3. Improper installation and maintenance
Failure to install or maintain according to the process will result in uneven stress on the sealing ring. Poor joint bonding when installing the sealing ring will cause the sealing ring interface to break. After subsequent grease injection of the pitch bearing, the sealing ring is prone to bulging, warping, and breakage. , causing the grease to overflow from the gaps, warpage, and damage to the sealing ring.
Failure to install or maintain according to the process will result in uneven stress on the sealing ring. Poor joint bonding when installing the sealing ring will cause the sealing ring interface to break. After subsequent grease injection of the pitch bearing, the sealing ring is prone to bulging, warping, and breakage. , causing the grease to overflow from the gaps, warpage, and damage to the sealing ring.
4. Extrusion damage
When installing or maintaining the blades of wind turbines, a hydraulic tensioner needs to be used to apply torque to the connecting bolts between the blades and the pitch bearing. The distance between the connecting bolts and the sealing ring is relatively close, and the drawing head of the hydraulic tensioner has a large overall size. The stretching head can easily press against the sealing ring, causing serious damage to the sealing ring.
When installing or maintaining the blades of wind turbines, a hydraulic tensioner needs to be used to apply torque to the connecting bolts between the blades and the pitch bearing. The distance between the connecting bolts and the sealing ring is relatively close, and the drawing head of the hydraulic tensioner has a large overall size. The stretching head can easily press against the sealing ring, causing serious damage to the sealing ring.
Certification
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