Detailed Procedures to Install and Mainten Slew Rings as Follows
Installation
-Handing
Slewing ring bearings, like any other machine part, require careful handling. To reduce the risk of injury,Use of safe operating practices and observation of all relevant legal regulations when handling,cleaning, and transporting are required. It is recommended that gloves be used whenever handling the bearing.Also, use carrying and lifting tools that are specially suited for mounting such bearings.
Slewing bearings should be transported and stored flat on a surface that extends over the whole side face of the bearing , preferably safely secured to shipping pallets or in a container. Eyebolts, for example, should only be subjected to a load in the direction of the shank axis. Also, keep in mind when using.Avoid any sudden acceleration or impact. If the bearing must be turned over, use nylon web slings or equivalent. Do not use chains or metallic mesh slings in contact with the bearing.
-Storage
Store only in horizontal position in closed rooms, if stacked there must be a stable intermediate layer. We recommend that you do not stack more than two high if the bearing is four feet or larger in diameter.The corrosion protection coating has a shelf-life of approx. 3 months in closed packaging. Longer storage periods require special protective measures. If the bearing is not installed within one year of receiving it, the grease should be purged and replaced with fresh grease.Outdoor storage is not recommended. External surfaces of slewing ring bearings, including the gear, are coated with a preservative oil to provide nominal protection during storage.
-Preparation-Cleaning
Installation of the bearing and gear assembly should be done in a clean, dry, well-lit area.
Remove extraneous material from supporting surfaces and pilots of the housings (including paint residues, welding beads, burr formation).
Clear corrosion protection coating from supporting surfaces of the Slewing Ring.Even "soft" material trapped between the mounting and bearing surfaces can result in high spots and affect bearing and bolt performance.
The purpose of cleaning material is that to stop penetrating into the Slewing Ring.
Cleaning material that attacks the sealing material is not used.
When this has been done, examine for and remove weld spatter, paint, nicks and burrs and wipe clean again.Mounting surfaces should be machined.
--Determining permissible flatness deviation perpendicularity deviation and permissible deformation of the mounting surface of the supporting structure
--Lubricating the Slewing Ring
Slewing Rings are supplied fully lubricated. They shall be greased again prior to initial operation.
Inject grease into all grease nipples one after the other,while rotating the Slewing Ring, until a bead of grease forms at least on one sealing lip.
-Positioning the Slew Ring
If one ring has a pilot or dowel hole, it should be positioned and mounted first.Consider alignment of gear's minimum backlash on structure so any necessary adjustments can be made.
Determine the main load-carrying zone.
For all Slewing Rings the soft spot of the Slewing Ring raceway shall be placed at a 90 deg point to the maximum load zone. The soft spot is designated with a filling plug or a punched “S” mark.
Do not expose the seal area or any other bearing opening to pressurized cleaning.
Use only cleaning material that is compatible with the seal material and avoid getting debris or other material into the bearing. Visually inspect and confirm that there is no damage to the bearing, gear, seals, or grease fittings.
Remove any minor burrs from mounting surfaces that may have occurred in shipping or handling. Use a hand file, taking care to remove only as much material as necessary to ensure full contact of bearing surface with equipment mounting surface. Make sure all surfaces are wiped clean.
With a gauge, check whether the supporting surface of the Slewing Ring is fully supported by the mounting structure.
-Securing the Slew Ring with bolts
The Slewing Ring shall be mounted in the unloaded condition.
First the toothless bearing ring is attached and then the gear bearing ring.
For good load distribution and smooth, low torque operation, the bearing should be as round as possible when the bolts are tightened. The following procedure is provided as an aid in achieving that objective.
The following procedure shall be followed in order to avoid deviations between the bolt tightening forces:
1.Lightly lubricate bolt threads in order to ensure uniform frictional resistance (does not apply to bolt locking devices with adhesive).
2.Preload the bolts, including washers, if required, crosswise in 3 steps with 30%,80%, 100% of the tightening torque or the hydraulically applied pretension force.
3.Thereby rotate the unbolted ring several times. Repeat the procedure for the bearing ring which has not yet been bolted.
When applying a hydraulic fastening device, the tightening forces for preloading shall not exceed 90% of yield stress.
4.Using a gauge, verify the bearing fully supports the mating structure. If not, then determine cause and correct.
5.Complete installation of all rotating components of significant weight, and check bearing for freedom of rotation. Excessive torque level, variation, or vibration is indicative of some unsatisfactory installation condition or component.
6.As permitted, inspect seals again for any damage.
-Determining the existing tilting clearance
When the equipment has been completely assembled, and prior to testing, check bolt tension to ensure that it is in compliance with that specified by the designer. The equipment should be oriented to generate as little moment or radial load on the bearing as possible to avoid inaccuracy in readings. Document this orientation so it may be used for all future bolt inspections. Any loss of pretensioning must be determined and eliminated.
The tilting clearance increases with raceway wear. To determine the increase in tilting clearance,it is necessary to take basic measurements after installation prior to putting the Slewing Ring into operation for the first time.Permanently designate the measuring point in the main load direction.
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