Swing Bearing for Hitachi EX300-2/3 — Internal Gear

The Heavy-Duty Swing Bearing for Large Hitachi Excavators is a reinforced heavy-load rotary support component exclusively developed for Hitachi 30–100 ton large mining & ultra-large construction excavators. This single-row ball reinforced internal slewing bearing delivers ultra-stable full 360° rotation, withstands extreme overturning torque, heavy continuous axial/radial impact loads, and maintains long service life under severe open-pit mine, quarry and mass earthmoving environments. Manufactured by BRISK SLEWING, this heavy internal gear swing bearing strictly complies with Hitachi heavy-duty OEM standards on forging thickness, alloy material and deep full heat treatment, supporting direct replacement without any structural cutting or modification. It is fully adapted to ultra-heavy working scenarios including large mine rock loading, mass land leveling, heavy demolition and port bulk cargo stacking. Our heavy swing bearing effectively cuts machine breakdown frequency and provides a budget-friendly alternative to genuine Hitachi heavy spare parts without sacrificing structural strength and operational safety.

The heavy internal gear swing bearing for Hitachi 30–100 ton large excavators adopts reinforced heavy-duty technical parameters:

Outer Diameter: 1620 mm; Inner Diameter: 1310 mm; Overall Height: 102 mm;

Gear Type: Internal gear (standard); Number of Teeth: 124; Module: 12;

Material: Thick-wall forged 42CrMo alloy steel, full quenched & tempered;

Raceway Hardness: HRC 56–63; Gear Surface Hardness: HRC 52–60;

Sealing: Triple lip thickened NBR dust-proof seal, high-temperature Viton seal optional for hot mining sites;

Lubrication: M12×1 grease nipple with wide deep circulating grease groove;

Precision Class: Grade P5 (ISO 286);

Dynamic Load Rating (axial): 1600 kN; Static Load Rating (axial): 4200 kN.

The thickened raceway and reinforced gear tooth design resist long-time heavy impact of large excavators. Each heavy slewing bearing passes full load simulation, hardness and backlash testing before delivery.

This heavy internal gear slewing ring is direct OEM replacement for Hitachi large excavators above 30 tons:

EX300, EX300-1, EX300-2, EX300-5, EX350, EX450, EX450-3, EX870, ZX300, ZX300-1, ZX300-2, ZX330, ZX450, ZX450-3, ZX450-5, ZX850.

The mounting hole uses M30 grade 10.9 super high-strength bolts with tightening torque of 1650 Nm. Our official installation manual marks the soft annealing zone which must be arranged at zero-load idle sector during assembly. We highly recommend measuring your original bearing outer diameter, inner diameter and overall height before ordering to avoid mismatching.

4. Quality Standards & Certification

BRISK SLEWING operates under ISO 9001:2025 quality management system. Each swing bearing undergoes a multi-step quality control process: Raw material verification – chemical composition analysis and ultrasonic testing for internal defects; Forging and heat treatment – controlled quenching & tempering to achieve uniform hardness; Machining – CNC turning and grinding of raceways with surface roughness ≤ Ra 0.8; Gear cutting – hobbing or shaping followed by induction hardening of tooth flanks; Magnetic particle inspection – 100% inspection of raceways and gear teeth for cracks; Dimensional inspection – CMM measurement of all critical dimensions; Noise and rotation test – smoothness verification under load simulation. All test reports and material certificates are kept traceable and can be provided upon request. We also offer third-party inspection by SGS, BV, or TÜV at the buyer's expense.

Hitachi large excavator heavy swing bearing bears ultra-severe heavy rotary loads in harsh industrial sites:

Open-pit mining & stone quarrying – long-cycle high-load rock digging and truck loading under dusty abrasive conditions;

Large-scale highway & hydropower earthmoving – full-load continuous swing with large-capacity heavy buckets;

Heavy demolition & scrap metal recycling – extreme impact from large hydraulic breakers;

Port bulk mineral handling – uninterrupted stacking and loading for 8+ hours daily;

Super large foundation & tunnel construction – heavy rock excavation and piling auxiliary operations.

This heavy internal gear bearing series also matches heavy crawler cranes and industrial heavy-duty turntables. The optimized thickened lubrication system extends maintenance intervals for non-stop heavy rotation work.

13+ Years of Experience – We have been manufacturing slewing rings since 2013, specializing in replacement parts for Hitachi, CAT, Doosan, Komatsu, and other major brands. Our engineering team understands the unique failure modes of each model.

500+ Technical Drawings – We maintain a library of CAD drawings covering most popular excavator and crane models. You can request a free 2D drawing for verification before ordering.

Global Shipping & Logistics – We ship to over 60 countries via sea, air, or rail. Our logistics partners provide door-to-door delivery with customs clearance support. Average lead time to South America, Africa, and Southeast Asia is 15-25 days.

24-Hour Quick Response – Send us an inquiry with your machine model or OEM number. You will receive a quote within 24 hours, along with technical advice from our engineers.

OEM-Grade Quality at Lower Cost – Our bearings meet or exceed OEM specifications but cost 30-40% less. We offer a 12-month warranty against manufacturing defects.

Customization Available – Non-standard sizes, special seals (e.g. Viton for high temperature), and alternative gear configurations are available. We also accept OEM branding and neutral packaging.

Free Technical Support – We provide installation guides, bolt torque charts, and online remote assistance. For large orders, we can arrange on-site training.

📖 Technical Guide: Read our Installation Guide for Large Hitachi Heavy Swing Bearing → for bolt torque specifications, soft zone placement, and maintenance tips.

Frequently Asked Questions

1. What is the OEM part number for large Hitachi excavator swing bearing?

− Hitachi ZX330/ZX450/EX450/EX870/ZX850 series all have exclusive heavy-duty OEM serial numbers. Provide your exact machine model, and we will match the corresponding reinforced SE-series large slewing bearing with identical thick-wall 42CrMo alloy material and deep quenching process for direct installation without modification.

2. Is this heavy internal gear slewing ring a direct replacement for Hitachi 30–100Ton large excavators?

− Yes, BRISK SLEWING heavy swing bearing is tailor-made OEM replacement for all Hitachi large diggers above 30 tons including EX300/350/450/870, ZX300/330/450/850 series. The bolt pattern adopts M30 grade 10.9 bolts with tightening torque of 1650 Nm. Always measure original bearing overall dimensions before placing orders.

3. What material and hardness grade are used for this heavy swing bearing?

− The heavy slewing ring is manufactured from thick-wall forged 42CrMo alloy steel with full quenching & tempering treatment, reaching raceway hardness HRC 56–63 and gear surface hardness HRC 52–60. Precision Grade P5 (ISO 286) guarantees stable rotation under extreme heavy mining loads.

4. What is the warranty period and do you provide technical drawings?

− BRISK SLEWING offers a 12-month warranty against manufacturing defects on all swing bearings. Yes, we maintain a library of 500+ CAD drawings covering most excavator and crane models. You can request a free 2D drawing for verification before ordering. Simply send us your machine model or OEM number, and our engineering team will provide the drawing within 24 hours.

5. How long does shipping take and which countries do you deliver to?

− We ship to over 60 countries worldwide via sea, air, or rail. Our logistics partners provide door-to-door delivery with customs clearance support. Average lead time to South America, Africa, and Southeast Asia is 15–25 days. For urgent orders, express air shipping is available. Contact our sales team for a precise delivery quote based on your location.