KD 320 slewing bearing

KD 320 Double-Row Ball Slewing Bearing | Heavy-Duty Turntable Ring for Excavators, Cranes & Offshore Equipment

Luoyang Heng Guan Bearing Technology Co., Ltd. engineers the KD 320 Slewing Bearing as a heavy-duty double-row ball solution for excavators, tower cranes, harbour cranes, and tunnel boring machines. This excavator slewing bearing double-row design spans ball track diameters from 755 mm to 4,140 mm, with ball sizes ranging from 20 mm to 50 mm. Manufactured from forged 42CrMo alloy steel with CNC-machined raceways hardened to HRC 55–62, each bearing delivers exceptional moment resistance and fatigue life. Available in both external and internal gear configurations, the product matches industry-standard mounting dimensions for direct replacement without equipment modification.

Why Choose KD 320 Double-Row Ball Design?

Two Rows, Maximum Capacity

Your equipment deserves more than single-row limitations. The product employs two concentric ball rows—the upper row with larger-diameter balls handles primary axial and tilting moment loads, while the lower row provides crucial radial and moment support. This dual-row configuration delivers significantly higher load ratings than equivalent single-row bearings within the same outer diameter, making it your best choice for tower crane slewing ring KD 320 applications where load capacity cannot be compromised.

Graduated Ball Diameter Selection

We offer eight ball diameter classes (20–50 mm) engineered for specific equipment weights. Twenty-millimeter balls suit 20–35 ton excavators and aerial platforms. Thirty-five to 40 mm balls power harbour crane slewing bearing and offshore deck cranes. Fifty-millimeter balls drive tunnel boring machine slewing bearing cutterheads and ultra-heavy steel mill ladle turret slewing ring assemblies. This graduated sizing lets you optimize cost and performance rather than oversizing your bearing selection.

External and Internal Gear Flexibility

Choose external gear (011 prefix) for standard excavator and crane installations where pinion access is straightforward and drive packages are readily available. Select internal gear (012 prefix) when your outer ring must remain clear for attachments, or when compact mobile crane slewing bearing double-row ball integration reduces overall machine width. Both configurations feature precision-hobbed or gear-shaped teeth manufactured to DIN 3967 / ISO 1328 quality standards with tooth profile verification on every unit.

Drop-In Replacement Compatibility

All KD 320 slewing bearing dimensions match your existing mounting dimensions when you provide drawings.. Bolt circle diameters, overall heights, ring thicknesses, and gear specifications ensure seamless replacement of your existing bearings without adapter plates or frame modifications. Send us your current bearing drawing or model code—we'll match every critical mounting dimension for hassle-free retrofit projects.

Technical Specifications

Representative External Gear Models (011 Series)

Representative Internal Gear Models (012 Series)

Detailed Parameters — Model 011.20.0755.000.11.1504

Proven Applications Across Heavy Industries

Excavators — The Standard Choice for Swing Drives

Your hydraulic excavator's upper structure—cab, engine, boom, and bucket—imposes complex axial deadweight, eccentric digging forces, and lateral loads. The double-row KD 320 handles this combined loading with higher capacity than single-row alternatives. External gear variants (011 prefix) with 20–25 mm ball diameters cover 20 to 45-ton excavator classes. Bolt patterns match factory-original interfaces for rebuild projects without adapter modifications.

Tower Cranes — High Moment Capacity Under Wind Loads

Tower crane slewing mechanisms with stacker reclaimer slewing ring requirements demand bearings that combine tilting moment capacity with smooth rotation under variable wind loads. Models in the 1,200–2,500 mm range with 25–35 mm balls support entire jib and tower head assemblies. The large pitch circle diameter enables high-torque transmission even under full wind exposure, while dual-row ball contact maintains jib alignment during load hoisting at radius.

Harbour and Offshore Cranes — Corrosion-Resistant Solutions

Portal harbour cranes and ship-to-shore container cranes operate in salt-laden marine atmospheres with continuous duty cycles. Bearings in the 1,700–3,150 mm range with 30–40 mm balls support rotating superstructures including boom, excavator house, and counterweight. For marine environments, we provide zinc thermal spray coating (TSZ), heavy-duty multi-lip sealing, and stainless steel bolt options where your specifications require enhanced protection.

Tunnel Boring Machines — Maximum Capacity for Cutterhead Drives

TBM main bearings represent the upper capacity limit of the series. Bearings exceeding 2,500 mm ball track diameter support cutterheads and transmit massive thrust and torque during hard-rock tunnelling. The primary ball row absorbs axial thrust from face advance while the secondary row handles radial loads from cutterhead eccentricity. Internal gear configurations distribute drive torque across multiple pinion engagement points—critical for multi-megawatt drive systems.

Manufacturing Excellence You Can Trust

Precision Materials and Heat Treatment

Every bearing starts with forged 42CrMo or 50Mn alloy steel rings—quenched and tempered for optimal core toughness. Raceways undergo induction hardening to HRC 55–62 with controlled hardened depth profiles verified by ultrasonic testing. Gear teeth are precision-hobbed (external) or gear-shaped (internal) to DIN 3967 / ISO 1328 quality standards.

Complete Dimensional Verification

We conduct 100% dimensional inspection using CMM and precision gauges. Raceway hardness mapping and rotational torque verification occur on every unit. Material certificates with full heat number traceability accompany every shipment, meeting the documentation requirements of international classification societies for offshore applications.

Flexible Customization Capabilities

Our engineering team provides on-site measurement and reverse engineering services when you lack original drawings. We deliver exact dimensional matching for retrofit projects, custom gear modules, enhanced sealing packages, and specialized corrosion protection for your unique operating environment. Non-standard bolt patterns and mounting interfaces can be accommodated upon request.

FAQ

Q: What advantages does the KD 320 double-row design offer over single-row bearings?

A: The dual-row ball configuration provides significantly higher axial, radial, and tilting moment capacity within the same outer diameter envelope. This makes it ideal for excavators and cranes where load capacity is the primary selection criterion.

Q: How do I choose between external and internal gear configurations?

A: Select external gear (011) for most excavator and crane applications where pinion access is straightforward. Choose internal gear (012) when your outer ring must remain clear for attachments or when the drive system integrates better within the bearing bore, such as in compact excavators and ladle turrets.

Q: Can you match my existing bearing dimensions exactly?

A: Yes. Provide your current bearing drawing or model code, and we'll match bolt circle diameters, hole counts and sizes, gear module, tooth count, and overall height. Custom bolt patterns are also available for non-standard installations.

Q: What corrosion protection do you offer for marine environments?

A: We provide zinc thermal spray coating (TSZ), multi-layer aluminum-zinc coatings, heavy-duty multi-lip seals, fluoroelastomer (FKM) chemical-resistant seals, and stainless steel fastener options. Full material certification with heat number traceability is standard for offshore-grade units.

Q: What are typical lead times for KD 320 bearings?

A: Standard catalogue sizes (DL 755–2,000 mm) ship within 30–45 days. Larger sizes (DL 2,000–4,140 mm) and custom configurations require 60–90 days. Contact Us with your required delivery date—we'll confirm feasibility for rush orders.

Q: Do you provide installation support?

A: Yes. Our engineering team offers installation guidance, bolt torque specifications, and on-site technical support to ensure proper mounting alignment and gear mesh verification for your successful commissioning.

Contact Us

Ready to specify the right offshore KD 320 slewing bearing ring or excavator slewing bearing for your equipment? Our engineering team will match your exact requirements—ball track diameter, gear type, bolt pattern, and quantity—within 24 hours.

Email: mia@hgb-bearing.com