Luoyang Slewing Bearing factory

Mounting and Lubrication Requirements for Slewing Rings:

1. Before mounting, remove all paint, grease and other foreign substances of both the structures
and bearing and check that the finish and flatness of the mounting surfaces are acceptable.

Theallowable surface finish is 125 rms maximum and the flatness must not exceed the following in
any 180° section: .005″ (.13mm) for bearings up to 20 inch (50.8 cm) diameter, .006″ (.15 mm) to
40 inch (101.6 cm) diameter and .007″ (.18 mm) up to 60 inch (152.4 cm) diameter. The maximum
out-of-flatness must not occur more than once in any 180° section.

2. The slewing bearing support structures must be sufficiently rigid and free of distortion during operation to
avoid uneven or localized loading on the bearing or the fasteners.

3. The non-heat treated zone (soft spot) on the bearing rings are identified by a filler plug on one ring
and typically the letter ‘G’ stamped on the other ring. The slewing rings shall be mounted such that the
soft spots are located in the application’s most lightly loaded region.

4. The high point of the gear teeth, where the runout is a maximum, is typically identified with blue
paint. This is the point where the backlash shall be set to the mating gear as follows: .006/.009″
(.15/.23 mm) for 5/7 pitch, .007/.011″ (.18/.28 mm) for 4/5 pitch, .008/.013″ (.2/.33 mm) for 3.5
pitch, .009/.014″ (.23/.36 mm) for 3 pitch, .011/.016″ (.28/.41 mm) for 2.5 pitch and .013/.018″
(.33/.46 mm) for 2 pitch.

5. Fastener design and performance is not the responsibility of LYMC. However,
the LYMC rating of the bearing assumes that the fasteners shall be grade 8 (w/ 120 ksi proof
strength) or better and shall be used with flat, hardened washers.

Fasteners shall be preloaded to
70% of the proof strength and periodically checked to be sure that this preload is maintained while
in service. All fasteners must be accessible. Do not use a thread locker such as Loctite.

6. Welding on or near the slewing ring bearing is not permitted.

7. Although grease is typically installed at the factory, the bearing raceway must be lubricated
before operation with an acid-free, non-resinous, water repellant, non-aging, extreme pressure
grease recommended for bearings.

Relubrication will be needed daily to monthly, depending on
the severity of the application. Pump the grease while slowly rotating the bearing until the grease
appears around the seal lips. Do not wipe away the ejected grease.

8. If the slewing bearing has gear teeth, the gear teeth will require a different grease than the bearing
raceway. Gear teeth are shipped from the factory dry.

LYMC recommends greases with a high lithiumcontent and which are also recommended for exposed gear teeth by the lubricant manufacturer.
Be sure to not mix greases as the grease used on the gear teeth must not be used in the bearing
raceway. Relubricate the gear teeth when relubricating the raceway.

2.How does the turntable bearing keeper structure and form affect rotational performance and reliability indicators?

Generally, the overall retention frame is the best, the box holder is again, the isolation block is most conservative, reducing friction, increase flexibility.

Copper cage, better than aluminum holders, second nylon segmented cage, polytetrafluoroethylene maintained the most economical.

During the design selection process, the working conditions must be complied with the technical route, which will also determine the form of the cage.

3.Nylon Cage Effect of  Slewing Bearing

The role of the holder is equivalent to the bones of the turntable bearing, while different materials, different structural cage, adapting to different working conditions, load, speed, installation methods and stress to the turntable bearings are particularly large. This paper introduces the effects of PTFE nylon retention holder steel retention frame copper retention frame on turntable bearings.

The nylon retention is a commonly used retaining frame, high toughness, oil-resistant corrosion-resistant resistance to a high and low temperature, -40 / + 60, beautiful, isolation block, box holder, basically satisfied with most of the conditions.

The segmented polytetrafluoroethylene holder, a good flexibility function, which is fully utilized at the four-point ball bearings, reducing friction, improving the rotation performance, is commonly used under high speed rotation, vertical mounting, tilt force.

Steel cage and copper retention frame, with respect to high temperature, dust, and high speed, adoption, cost is relatively high.

4.How does a slew ring work and what are its component parts?

Two concentric rings make up the main structure of a slewing bearing. The outer ring usually lies flat against a motionless surface and is screwed into place via evenly spaced mounting holes. The inner ring is usually affixed to a turning object via an adapter plate or bracket. It usually moves in a rotational manner while the outer ring stays affixed to the mounting surface.

Relative rotation between rings is facilitated either by rolling or sliding elements. For slewing bearing that operate with ball bearings, parts that facilitate greasing of the system are included, such as seals, load plugs, grease fittings and taper pins. For slewing rings that are based on sliding elements, replaceable plastic liners lie between the inner and outer rings.

Because slewing beaerings based on ball bearings have very small contact points (ball bearings touching the inner and outer ring surfaces), they are able to move with very low friction.

Slewing rings that are based on plastic liners to facilitate movement (with a larger inner ring surface to better handle heavier loads) work better for flat, horizontal applications . Vertical applications are better suited for ball bearing-based slewing rings.

Both slewing ring types can include gears on the outer ring OD or the inner ring ID to facilitate different application requirements.

The different ways to drive a slewing ring include:

• External gear
• External belt
• Worm gear
• Drive-plate coupling

Electrical Insulation

One distinct advantage of a slewing bearing using plastic liners is that it is electrically insulating. That is, cables can run through the center of the slewing without requiring any additional layer of polymer or any other form of grounding. Slewing bearings based on ball bearings, in contrast, require an additional layer of polymer or some form of grounding in order to prevent electricity from traveling through the slewing ring from the cables.