VSA251055-N Slewing Bearings
Gear: External gear, module m10 / 118 teeth, pitch circle d0 per medias official data
Dimensions: bore 955 mm × OD ? mm × height 80 mm, weight 171 kg (Schaeffler medias official)
Load capacity: dynamic axial Ca = 385 kN, static axial C0a = 3,750 kN, dynamic radial Cr = 350 kN, static radial C0r = 1,720 kN
Tooth force Fz max = 89.0 kN (per medias data)
Max. radial load on fixing screws Fr zul = 530.0 kN (friction-locking mount)
Clearance spec: Normal: 0.03–0.13 mm; precision class P0 / P6 / P5 available
Material: 50Mn / 42CrMo4 rings, GCr15 balls, double-lip NBR seals, -25 to +80 °C operating range
Standard series envelope — mounting-compatible with the whole VSA Standard 25 family across the 414 → 1094 (or 755 → 1055) raceway range
Primary application: Heavy Cranes and Wind Yaw (25-series largest external gear)
- Product Description
VSA251055-N Slewing Bearings — INA VSA25 Series External Gear Four-Point Contact Ball Ring
The VSA251055-N Slewing Bearings are the biggest external-gear variation in the INA VSA Standard 25 series. Using a single-row four-point contact ball construction, this 80 mm ring bears axial, radial, and tilting moment stresses. It is designed for big cranes, wind turbine yaw systems, and large construction machines that need combined loading and external pinion access. It has a 955 mm diameter, 171 kg mass, and 3,750 kN static axial load rating.
Luoyang Heng Guan Bearing Technology Co., Ltd. makes P0, P6, P5, and P4 precision slewing bearings from 50 to 10,000 mm diameter. The ISO 9001-certified firm has delivered bearings to the US, Germany, the UK, Norway, Australia, the Middle East, and over 40 other nations.
What Is the VSA251055-N?
The VSA251055-N is an external-gear slewing ring from the INA VSA Standard 25 family. Its single-row four-point contact ball design allows one ball row to handle axial, radial, and tilting moment loads simultaneously, which reduces overall assembly height compared with multi-row arrangements.
The external gear carries module m10 with 118 teeth on a 1,180 mm pitch circle — the only m10 external gear configuration in the entire VSA 25 family. The normalized (N) tooth profile enables a pinion or worm to mesh from outside the ring, keeping the drive unit accessible for inspection and maintenance without dismounting the bearing.
Technical Specifications
Parameter | Value |
Model | VSA251055-N |
Structure | Four-point contact ball / single row |
Inner ring bore (di) | 955 mm |
Outside diameter | 1,198 mm |
Total height (H) | 80 mm |
Weight | 171 kg |
Gear type | External |
Gear module (m) | 10 |
Number of teeth (z) | 118 |
Gear pitch circle (d0) | 1,180 mm |
Tooth profile | Normalized (N) |
Dynamic axial load (Ca) | 385 kN |
Static axial load (C0a) | 3,750 kN |
Dynamic radial load (Cr) | 350 kN |
Static radial load (C0r) | 1,720 kN |
Max. tooth force — continuous | 61.2 kN |
Max. tooth force — peak | 89.0 kN |
Max. radial load, fixing screws (Fr zul) | 363,000 N |
Inner bolt circle (Li) / qty | 995 mm / 30 × 22 mm through-holes |
Outer bolt circle / qty | 1,116 mm / 30 × M20 threaded holes |
Radial clearance (Normal) | 0.03–0.13 mm |
Operating temperature | −25 to +80 °C |
Ring material | 50Mn / 42CrMo4 |
Ball material | GCr15 |
Seal | Double-lip NBR |
Precision class | P0 / P6 / P5 |
Dimensional and load data sourced from the Schaeffler medias official catalogue.
Design Features
Single-row four-point contact ball structure. One ball row carries combined axial, radial, and tilting moment loads, eliminating the need for separate thrust and radial rows. This keeps the section height at 80 mm regardless of the raceway diameter.
Largest external gear in the VSA 25 family. The m10/z118 configuration steps up from the VSA250955-N's m9/z120 gear. Static axial capacity increases from 3,400 kN to 3,750 kN within the same 80 mm section height, offering higher load capacity without increasing the structural envelope.
50Mn / 42CrMo4 ring steel with induction-hardened raceways. Raceway surface hardness reaches 55–62 HRC for fatigue resistance, while the core remains ductile to absorb shock loading. GCr15 bearing balls are used throughout the ball set.
Double-lip NBR seals. The standard seal configuration covers the −25 to +80 °C operating temperature range and provides protection against dust and moisture ingress under normal industrial conditions.
Fixing-hole pattern, per size. The VSA251055-N uses 30 × 22 mm through-holes on a 995 mm inner bolt circle and 30 × M20 threaded holes on a 1,116 mm outer bolt circle. Each size in the standard series 25 has its own pattern — the 0755, 0855 and 0955 sizes use different bolt circles and hole counts — so the pattern must be confirmed against the mounting flange before a different size is specified.
Typical Applications
Heavy cranes and lifting equipment. Tower cranes and large mobile cranes with external pinion swing drives benefit from the 3,750 kN static axial rating, which is sized to absorb peak shock loads during heavy lifts.
Wind turbine yaw systems. Large wind turbines position yaw drive pinions at the tower top and mesh them against the external gear ring. The accessible external gear location reduces the complexity of maintenance procedures at height.
Excavators and construction excavator. In the 60–90 tonne excavator class, the swing system typically pairs this m10 external gear with an external swing pinion. The 3,750 kN static axial capacity is consistent with the shock loading profiles of heavy digging cycles.
Solar tracker slewing drives. Utility-scale solar trackers using worm drives meshing against the external gear from outside can use the m10 tooth section and tilt moment capacity for large single-axis and dual-axis tracker frames.
Mining and offshore equipment. Large mining shovels, offshore drilling turntables, and deck cranes use the sealed four-point contact design together with the 363,000 N fixing-screw radial load rating for applications requiring combined loads and sealed operation.
Manufacturing and Quality
Heng Guan Bearing machines VSA251055-N Slewing Bearings in-house in Luoyang using CNC vertical lathes, CNC gear shapers, large gear hobbing machines, and CNC quenching machines. Each bearing passes through coordinate measuring machine inspection, vibration testing, and load testing before shipment. Raw material traceability is maintained from steel input through to finished product.
Products are manufactured in compliance with DIN, ISO, and GB standards. OEM/ODM support, installation documentation, and non-standard dimensional customization are available on request. Standard stock items ship within 2–3 business days; Contact Us directly for bulk order lead times.
FAQ
Q: What is the VSA251055-N's outside diameter?
A: The outer diameter is 1,198 mm. The bore is 955 mm, section height 80 mm, and weight 171 kg.
Q: How is VSA251055-N different from VSA250955-N?
A: They share 80 mm section height. With a m10/z118 gear and 3,750 kN static axial rating, the VSA251055-N weighs 171 kg, whereas the VSA250955-N weighs 155 kg with a m9/z120 gear and 3,400 kN.
Q: What bolt quality is suggested for installation?
A: Grade 12.9 bolts are allowed but need the manufacturer's load conversion factors and a higher tightening torque. Published load values are based on grade 10.9 ISO 898-1 bolts. The hardness gap (the unhardened zone between raceway hardening's start and finish, defined by the closing plug) should be 90° away from the zone under maximum load to avoid peak raceway stress.
Q: What is the recommended re-lubrication interval?
A: The racetrack operates every 100 hours and open gears every 50. Increase frequency to remove moisture in high-humidity areas.
Q: Is the VSA251055-N in stock?
A: MOQ 1 piece, standard stock models arrive in 2–3 business days.
Contact Us
For technical enquiries, pricing, or CAD drawings related to VSA251055-N Slewing Bearings, reach our engineering team directly at mia@hgb-bearing.com.
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