VSA200944-N Slewing Bearings

VSA200944-N Slewing Bearings — External Gear Four-Point Contact Ball Slewing Ring for Cranes & Wind Yaw Systems

VSA200944-N Slewing Bearings are a single-row, four-point contact ball slewing ring with a 944 mm raceway diameter, external gear (m8/z129), and a static axial load capacity of 1,520 kN. Designed as a mounting-compatible replacement for the INA VSA Standard 20 series, the bearing weighs 77.23 kg and stands 56 mm tall — suited for mid-size crane slewing sections and wind turbine yaw systems where a compact section height and high static axial margin both matter.

Luoyang Heng Guan Bearing Technology Co., Ltd. manufactures and supplies this bearing from its facility in Luoyang, China.

Full Technical Specifications

Design and Engineering Notes

The four-point contact ball structure allows a single ball row to carry axial loads, radial loads, and tilting moments simultaneously. This removes the need for multiple bearing rows when handling combined forces, which is relevant when axial section height is constrained to 56 mm.

The external gear is module 8 with 129 teeth, supplied with normalized (N) gear teeth — the N suffix denotes the heat-treatment condition of the teeth, not a tooth profile. A drive pinion meshes from outside the ring OD, keeping the drive system accessible for inspection and maintenance without removing the full slewing section. Permissible tooth force is rated at 28.3 kN (fatigue strength) and 42.0 kN against tooth fracture, per the Schaeffler medias catalogue.

At the 944 mm raceway band, C0a reaches 1,520 kN. For comparison, the 844 mm band in the same series carries C0a 1,360 kN at the same 56 mm section height. The 944 mm option therefore provides roughly 12% more static axial capacity without increasing the section height — a useful consideration when load requirements change during a platform redesign.

Ring material is 50Mn or 42CrMo4 steel; rolling balls are GCr15. Raceways are induction-hardened to 55–62 HRC for fatigue resistance, with a ductile core to absorb shock loads. Double-lip NBR seals protect raceway grease from contamination across the full -25 to +80 °C operating range.

Mounting bolts: grade 10.9 to ISO 898-1 is the specification on which the published load ratings are based; grade 12.9 is permissible but requires the manufacturer's load conversion factors and a higher tightening torque. The outer bolt circle accepts 40 holes on a 985 mm PCD; the inner circle accepts 44 holes on an 898 mm PCD. Position the hardness gap (the unhardened soft zone between the start and end of raceway hardening, marked by the closing plug) 90° away from the zone under maximum load, so the unhardened zone stays clear of the peak raceway stress.

Typical Application Areas

Cranes and Lifting Platforms — Tower cranes and mid-size mobile cranes commonly pair external-gear slewing rings with outer pinion drives at this diameter range. The C0a of 1,520 kN provides the static load margin needed for heavy hook loads and sudden tilting moments.

Wind Turbine Yaw Systems — Mid-size wind turbines mount external-gear yaw VSA200944-N Slewing Bearings on the tower top, with drive pinions that remain accessible for maintenance at height. The double-lip NBR seal and -25 to +80 °C operating range suit extended outdoor service.

Excavators and Construction Excavator — Large excavators use external-gear rings with a swing pinion positioned outside the ring OD. The four-point contact structure handles the shock and vibration loads typical of digging cycles at this diameter.

Solar Trackers and Slewing Drives — Worm drives mesh with the external m8/z129 gear from outside the OD while the ring bore hosts the tracker pivot. The 944 mm raceway carries tilt moments from large tracker structures across repeated daily actuation cycles.

Radar, Antenna, and Rotary Indexing Platforms — Large radar dishes and rotary indexers that require a side-mounted pinion drive rather than an under-table arrangement are a standard fit for this external-gear configuration.

Supply and Quality Information

Orders are confirmed within 24 hours of inquiry. Precision grades P0, P6, P5, and P4 are all available as standard options.

Quality verification includes coordinate measuring machines, vibration testing, and full material traceability from raw stock to finished bearing. Products are manufactured to DIN, ISO, and GB standards and are RoHS compliant.

OEM and ODM partnerships are available, along with technical support for cross-referencing legacy part numbers, installation guidance, and non-standard machined components such as large gears, ring gears, and couplings.

FAQ

Q: What is VSA200944-N, and what series does it belong to?

A: It is an external-gear, four-point contact ball slewing ring equivalent to the INA VSA200944-N (VSA 20 0944 N). Key dimensions: 872 mm bore × 1,046.1 mm OD × 56 mm height, 944 mm raceway diameter, 77.23 kg. Its fixing-hole pattern (La 985 mm / 40 holes, Li 898 mm / 44 holes) and 56 mm height match the VSA 20 0944 N envelope; other sizes in the series use different bolt patterns.

Q: What are the gear specifications?

A: External gear, module 8, 129 teeth, pitch circle 1,032 mm, normalized (N) gear teeth. Permissible tooth force per the Schaeffler medias catalogue: 28.3 kN (fatigue strength) / 42.0 kN against tooth fracture.

Q: How does the VSA200944-N compare to VSA200844-N?

A: Both share the same 56 mm section height. The products offer a 944 mm raceway (m8/z129, C0a 1,520 kN, 77.23 kg) versus the 844-N's 844 mm raceway (m8/z117, C0a 1,360 kN). This represents approximately 12% more static axial capacity within the same axial envelope.

Q: What are the main causes of slewing bearing failure, and how can I reduce the risk?

A: Inadequate lubrication and contamination leading to raceway spalling are among the most frequently cited causes. As guide values, relubricate the raceway at about 100 operating hours in outdoor service, and the gear teeth at half that interval; in clean indoor installations the guide interval extends to about 500 hours. Relubricate after cleaning, before and after long stoppages, and more frequently in high humidity. Check the fixing screws and the tilting clearance every 500 operating hours, or at least every six months — the maximum permissible increase in tilting clearance is 0.035 × DW + 0.6 mm, which is 1.3 mm for this VS 20 slewing ring.

Q: What precision grades are available for the products?

A: P0, P6, P5, and P4 are available as standard precision grades. Contact the team with your application requirements to confirm the appropriate grade.

Contact Us

For pricing, CAD drawings, or technical support on VSA200944-N Slewing Bearings, contact Luoyang Heng Guan Bearing Technology Co., Ltd. directly at mia@hgb-bearing.com.