While slewing ring bearings do perform heavy-duty functions often under the worst possible conditions, they must be treated as delicate instruments to ensure their accuracy and a long operating life. Following the installation procedures precisely is critical to ensuring the best possible performance.Slewing rings are vital to supporting heavy loads that must rotate to other positions in a precise manner. Devices that use slewing bearing rings include massive construction cranes, large solar tracking devices, and even some types of military armament. Since the rotation of the mechanism demands accuracy to assure effectiveness and safety, the installation of slewing ring bearings requires precision to expect proper operation.
Complying with every detail of the instructions is necessary for proper installation and function. Here are some installation tips that highlight the need for proper care of this powerful, yet sensitive equipment.
Making Sure the Bearings are Shipped and Stored Properly
When the manufacturer prepares the slewing ring bearings for shipment, they are lightly lubricated, wrapped for delivery, and packed in individual specialized containers.
After receiving, store the unit in a clean, dry place in the original packing material until installation. Ensure that all areas around the slewing ring bearings are free of grit and dirt.
Always Inspect for Distortion or Interference from Debris
Each component of the slewing ring bearing must be clean, unobstructed by even the smallest foreign object, and precisely oriented. Problems may arise during operation when friction or out-of-balance situations occur. The load may tend to concentrate in a particular area, creating a malfunction or improper wearing.
Ensure Support Surfaces are Level and Strong
The supporting surfaces must be machined smooth and perfectly level. They need to have sufficient strength to remain rigid during operation to eliminate any possible vibration or buckling due to imbalance.
Check the Ring Circularity
Protecting all elements of the slewing ring bearing is essential. If the circularity of the slewing ring is compromised during shipment and handling, the slewing drive will not work properly. Slewing ring bearings should be transported and stored in purpose-built crates and kept in a horizontal position at all times.
Ensure that the lifting apparatus or sling used is sufficiently robust and capable of lifting and holding the ring during installation. The external gear teeth must have protection to guard against damage from any collision with other surfaces.
Slewing ring equipment should not be in storage longer than six months. The raceways must always be kept greased and free of rust.
Proper Sealing and Lubrication
Installers should specify integral seals on bearings and incorporate shrouding to protect the gears and bearings.
As with most metal machine parts, proper lubrication is essential to smooth operations and long life. For slew ring bearings and gears, this process is crucial. Equipment will come with operating instructions that will advise a recommended frequency for lubricating. Lubrication schedules depend on the type of equipment and the amount of use.
Immediately after assembly, you should lubricate the gear with either a brush or spray-on. Gear lube is recommended at least every three months depending on how rigorously the equipment is used.
Double-Check the Installation Instructions and Perform Tests Before Use
Follow the manufacturer’s installation directions to the letter.
During installation, the slewing rings should be rotated while bolts are tightened to determine if any tight spots are developing. Also, recheck the bolt torque to identify any change due to settling.
Once the ring bearing is in position, check for any gear backlash and bearing torque before putting into operation. Deviations can indicate a problem with the mounting process.