021.30.900 Slewing Bearing
2. 021 is the standard external gear type of the 02 series: the gear is machined on the outer ring of the bearing, and the driving pinion meshes from the outside. The double row different anterior ball structure provides 40-60% higher load-bearing capacity than a single row, and the external gear configuration provides maximum torque transmission and easy maintenance accessibility.
- Product Description
021.30.900 Slewing Bearing – External Gear Double Row for Heavy Equipment
Luoyang Heng Guan Bearing Technology Co., Ltd., a modern enterprise with over 30 years of bearing manufacturing expertise, specializes in the 021.30.900 Slewing Bearing—a double-row external gear turntable bearing engineered for 15-30 ton excavators, tower cranes, and wind turbine yaw systems. This excavator external gear slewing bearing 900mm features m=8 module with 133 teeth hardened to 55-62 HRC, delivering 1042mm OD × 758mm ID × 124mm height. With 80 kN tooth force (normalized) or 111 kN (quenched), it handles severe shock loads in construction lifting excavator. ISO9001 certified, our facility in Luoyang—China's bearing hub—produces slewing bearings from 50-10,000mm diameter with P0 to P4 precision grades. Products reach 50+ countries across Europe, North America, and the Middle East.
Product Overview
The product belongs to the 02 series double-row different-diameter ball structure with external gear configuration. This large excavator swing bearing external gear design positions 133 gear teeth on the outer ring circumference, enabling pinion engagement from outside the bearing envelope. The dual-raceway architecture provides 40-60% higher load capacity compared to single-row equivalents at identical dimensions.
External gear positioning is the dominant solution for 10-30 ton excavators, mobile cranes, and wind turbine yaw drives. The tower crane slewing bearing external gear double row configuration allows drivetrain maintenance without bearing disassembly—a critical advantage during field repairs. This model fully interchanges with SNOR30/900 specifications, ensuring drop-in replacement for existing equipment.
Technical Specifications
Basic Dimensions
Parameter | Symbol | Value |
Outer Diameter | Da | 1042 mm |
Inner Diameter | Di | 758 mm |
Height | H | 124 mm |
Raceway Center Diameter | DL | 900 mm |
Ball Diameter | Dw | 30 mm |
Weight | — | ≈250 kg |
Installation Dimensions
Parameter | Symbol | Value |
Bolt Circle (Outer) | D₁ | 998 mm |
Bolt Circle (Inner) | D₂ | 802 mm |
Bolt Holes (Outer Ring) | n | 30 |
Bolt Holes (Inner Ring) | n₁ | 22 |
Mounting Bolt | — | M22 |
External Gear Data
Parameter | Symbol | Value |
Module | m | 8 |
Number of Teeth | Z | 133 |
Tip Diameter | De | 1086.4 mm |
Profile Shift Coefficient | x | +0.5 |
Face Width | b | 80 mm |
Pressure Angle | α | 20° |
Tooth Hardness | — | 55–62 HRC (Induction) |
Gear Accuracy | — | DIN 8 / AGMA Equivalent |
Max Tangential Force (Normalized) | Ft | 80,000 N |
Max Tangential Force (Quenched) | Ft | 111,000 N |
What This Means for Your Design
The 80 kN normalized tooth force suits standard duty cycles in truck crane operations. For frequent start-stop applications or impact loading—such as rock breaker attachments on excavators—the 111 kN quenched variant prevents tooth root fatigue. This specification transparency helps you match bearing selection to actual field conditions, avoiding premature failures common with under-specified alternatives.
Double Row + External Gear Value
Why 021 (Double Row + External Gear) Dominates This Size Class
1. Double-Row Load Separation
Upper and lower raceways independently handle axial and tilting moments without mutual compromise. Single-row designs force these loads onto one contact path, causing accelerated wear.
2. External Gear Accessibility
Pinion meshes from outside the bearing body. You can replace drive motors or inspect gear mesh without disassembling the entire slewing ring—a maintenance advantage worth thousands in downtime costs.
3. Torque Maximization
External gears achieve larger pitch diameters than internal equivalents at the same envelope size. This geometry directly increases your output torque capability.
4. Application Matching
· Excavators (impact + high torque) → Choose 021 external gear
· Space-constrained drill rigs → Select 023 internal gear
· External actuator drives → Use 020 non-gear with custom coupling
Load Capacity
Parameter | Symbol | Value |
Axial Static Load | C₀ₐ | ≈2,580 kN |
Radial Static Load | C₀ᵣ | ≈2,200 kN |
Tilting Moment | Mₜ | ≈850 kN·m |
Max Rotational Speed | nₘₐₓ | ≤50 rpm |
These ratings assume proper preload and lubrication per installation manual. Exceeding rated speeds causes centrifugal roller skidding.
Applications
15-30 Ton Excavators
The crawler crane slewing ring external gear layout is standard for mid-size excavator lower frames. It simultaneously resists digging-induced tilting moments plus upper structure dead weight—typically 400-600 kN combined loading.
Tower Cranes
Double-row construction provides the anti-wind-load stiffness tower cranes require at height. The construction lifting excavator slewing ring ensures smooth rotation under asymmetric boom loads.
Crawler & Truck Cranes
External gear drive is the factory-standard configuration for 20-50 ton mobile cranes. The truck crane turntable bearing external gear 1m diameter class offers optimal strength-to-weight ratio for highway transport limits.
Wind Turbine Yaw Systems
The wind turbine yaw bearing external gear in megawatt-class nacelles uses this 900mm raceway diameter. Double-row design withstands asymmetric wind shear while external gears simplify yaw motor integration.
Port Excavator
Shiploader and portal crane slewing systems benefit from external gear serviceability during 24/7 operations. The port excavator slewing ring external gear withstands frequent start-stop cycles in corrosive marine environments.
Series Comparison
Feature | 020.30.900 | 021.30.900 | 023.30.900 |
Gear Type | Non-Gear | External Gear | Internal Gear |
Gear Position | — | Outer ring face | Inner ring bore |
Module / Teeth | Custom | m=8, Z=133 | m=8 |
Tip Circle | — | De=1088 mm | Inside bore |
Pinion Access | — | Easy (outside) | Requires internal clearance |
Tooth Force | — | 80-111 kN | — |
Best For | External actuators | Excavators, cranes, wind yaw | Space-constrained turrets |
SNOR30/900 Cross Reference
The 021.30.900 Slewing Bearing fully interchanges with SNOR30/900 and SNOR30/900Y models. Verify these parameters for compatibility:
· Da: 1042 mm
· Di: 758 mm
· H: 124 mm
· D₁: 998 mm
· D₂: 802 mm
· Module: 8
· Teeth: 133
This dimensional equivalence allows you to source from multiple vendors without redesigning housings—critical for aftermarket service parts.
OEM & Custom Manufacturing
We customize non-standard modules, tooth counts, and hardness zones to match your gearbox reduction ratios or unique load profiles. Our heavy equipment external gear turntable bearing service includes:
· On-site measurement for obsolete equipment without original drawings
· Reverse engineering to optimize worn component designs
· CAD drawings provided within 48 hours of inquiry
· Salt spray & high-temperature coatings for marine or desert environments
FAQ
Q: Can this bearing replace SNOR30/900 directly?
A: Yes. All mounting dimensions and gear parameters match. Verify bolt hole patterns before ordering.
Q: What's the difference between 80 kN and 111 kN tooth force ratings?
A: 80 kN applies to normalized gears for standard duty. 111 kN uses induction-hardened teeth for impact loading like hydraulic hammers.
Q: How do I prevent gear mesh noise?
A: Ensure pinion center distance accuracy within ±0.2mm and use ISO VG 220 gear oil with MoS₂ additives.
Q: What's your lead time for custom tooth counts?
A: Standard 021.30.900 ships in 15 days. Custom gear machining adds 10-12 days.
Q: Do you provide installation tools?
A: We supply torque charts and pre-load measurement procedures. Hydraulic tensioners available separately.
Contact Us
Need load calculations for your specific application with 021.30.900 Slewing Bearing? Our engineering team provides free selection assistance, including FEA analysis for critical projects. The construction excavator double row slewing ring in your equipment deserves precision manufacturing backed by 30 years of Luoyang bearing expertise.
Email: mia@hgb-bearing.com
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