Guidelines for the installation and commissioning of slewing rings to avoid pits

What is slewing bearing

Slewing bearing, also known as slewing plate bearing, is a large bearing that can bear axial force, radial force and overturning moment at the same time, mainly used to realize the rotation or swing function of equipment. The core structure includes the inner ring, outer ring, raceway, rolling elements (balls or rollers) and seals, which are precisely designed for smooth rotation and high load capacity.

Main Application Areas

Construction machinery: such as the rotating platform of cranes and excavators, and the steering mechanism of pavers.

New energy equipment: nacelle support and yaw system for wind turbines, solar tracking brackets.

Industrial equipment: rotating pedestals for harbor cranes, radar antennas, stackers, reclaimers, etc.

Traffic & Transportation: High-speed rail pantographs, ship deck equipment, rail inspection vehicles.

Special areas: rotating racks for medical CT machines, missile launchers, docking mechanisms for spacecraft.

Everyday machinery: Ferris wheels, merry-go-rounds, header rotation for agricultural machinery.

Preparation Before Installation

Inspect the foundation and mounting surface

Make sure that the mounting surface is flat and the levelness error is ≤ 0.1mm/m (use a spirit level or laser calibrator).

Clean up the debris on the installation surface to avoid oil stains or rust affecting the fixation.

Check the size and model

Confirm that the model, bolt hole spacing, and installation direction of the slewing ring are consistent with the design drawings.

Check whether the rolling elements and seals are in good condition to avoid damage during transportation.

Preparation of tools and materials

Use a torque wrench (±5% accuracy) to control bolt preload to avoid overtightening or loosening.

Prepare grease (choose the model according to the manufacturer's requirements), cleaning agent, anti-loosening glue, etc.

The Installation Process of Pit Avoidance Points

Hoisting and positioning

Use a special spreader to avoid directly lifting the outer ring (which is easy to cause deformation).

Align the bolt hole and lower it slowly to prevent collisions.

Bolt tightening sequence

Using the symmetrical cross fastening method (e.g., 1→3→5→2→4→6), the rated torque is gradually reached in 2-3 steps.

The preload is required to meet the manufacturer's specifications (typically 70%-80% of the yield strength of the bolt material).

Anti-loosening treatment

Use high-strength bolts (e.g., grade 10.9 or higher) with anti-loosening rubber or spring washers.

It is forbidden to reuse bolts that have been stretched and deformed.

Lubrication and sealing

Apply grease evenly in the raceway before installation to avoid excessive heating.

Check whether the sealing ring fits well to prevent dust and water from entering the interior.

Precautions in The Commissioning Stage

No-load test run

Spin at low speed for 10-15 minutes and observe for stuttering, squeaks, or heat.

The initial operating resistance torque is recorded and compared with the manufacturer's data.

Load testing

Load step by step to the rated load and check that the radial/axial clearance of the bearing is within the allowable range (usually ≤ 0.2mm).

Avoid sudden loading or overloading to prevent raceway indentation.

Vibration and noise detection

Vibration values are monitored using a vibration detector (normal range≤ 2.5 mm/s).

Abnormal noise may indicate rolling element damage or installation deviation, and it is necessary to stop the machine immediately for troubleshooting.

Temperature monitoring

After 1 hour of continuous operation, the bearing temperature should be stable and ≤ 70°C (ambient temperature ≤ 40°C).

A sudden increase in temperature can be caused by insufficient lubrication or over-tight installation.

Common Problems And Solutions

During installation and commissioning, if the following problems occur, they need to be troubled in time:

Abnormal operation noise

It can be caused by raceway contamination or wear of the rolling elements. The raceways need to be cleaned and greased, and the bearings need to be replaced if they are severely worn.

Loose bolts

It is usually caused by insufficient preload or failure of anti-loosening measures. It is necessary to use a torque wrench to re-tighten the bolt according to the specification, and supplement the anti-loosening glue to enhance the fixing effect.

Fever is severe

It can be caused by insufficient lubrication or over-tight installation. It is necessary to check the amount of grease filled and replenished, and adjust the installation clearance to a reasonable range.

Vibration exceeded

The most common cause is an uneven mounting surface or excessive bearing clearance. The levelness of the mounting surface needs to be calibrated and the clearance can be controlled by adjusting the gasket or preload.

Maintenance Suggestions

Lubricate regularly: Replenish grease every 500 hours of operation to avoid mixing different brands of grease.

Seal inspection: check the wear of the sealing ring every month, and replace the aging parts in time.

Bolt retightening: The bolts need to be retightened after 200 hours of operation of the new machine, and then checked quarterly.

Slewing Ring Supplier

As a leading supplier of industrial transmission solutions in China, LTZC Slewing Bearing Co., Ltd. focuses on the R&D, manufacturing and service of high-precision slewing rings, and is committed to providing global customers with efficient and reliable rotary motion control products. Founded in 2008, relying on independent innovation technology and modern production base, the company has formed a large-scale production capacity of 100,000 sets of slewing rings per year, and has passed ISO 9001, ISO 14001 and other international certifications, and its products are widely used in construction machinery, port machinery, wind power generation, medical equipment and aerospace and other fields.

LTZC continues to promote the innovation of slewing ring technology and help upgrade industrial equipment around the world. If you want to know more about our products or get customized solutions, please contact our professional team, we will provide you with the best solution!