Inadequate lubrication is the most common cause of premature light bearing failures. In light slewing ring bearings, a heavy-duty, extreme pressure grease is required. When lubrication is inadequate, surface damage in the form of roughening or waviness occurs. Later, fine cracks develop, followed by flaking. Failures due to contamination are fairly common. Dirt or other debris within the lubrication system act as an abrasive and accelerate the wear. Usually the bearing raceways are scratched or indented, again leading to fine cracking and, ultimately, spalling.
So a suitable lubrication is essential for the longevity of the raceways and gears. The operating conditions such as loads,temperatures, speeds, vibrations, etc... determine the choice of lubricant.
Unless otherwise specified, the slewing rings are delivered greased.
Standard grease : Mobilux EP2 or equivalent.
Main properties required for multipurpose grease :
As being a significant component of the bearing,
grease will improve the bearing capabilities and longevity.
Recommendations for bearing lubricant :
• Lithium-base soap.
• Minimum viscosity of the base : 150 mm 2 /sec.
• Grade NLGI 2.
• Anti-wear and extreme pressure additives.
• Service temperature :
– 40 ° C to + 120 ° C
• 4 ball test : weld load : ASTM D 2596 (NT24) > 300
• Maximum NDM :
for balls = 60 000
for rollers = 30 000
A slewing mechanism is a mechanism that rotates a slewing arm davit around a turning centerline in a horizontal plane, and it is one of the main working mechanisms of a slewing arm davit. The role of the slewing mechanism is to achieve horizontal movement of the goods. Through the cooperation of the three mechanisms of lifting, luffing and turning, the goods can be transported to any position within the range of the working range of the slewing arm davit.