Project Overview

Brazilian iron ore and gravel mines are no playground for the Hitachi ZX470. Constant heavy digging, frequent slewing, and grit everywhere put extreme stress on the original bearings. We stepped in with a custom internal-gear slewing ring that meets Hitachi’s OEM standards and lasts through the long shifts common on local sites.

The single-row four-point contact ring is forged from 42CrMo steel, with CNC-drilled blocking and oil holes. We quench the raceways and gear teeth integrally to DIN Class 7 hardness – that’s what resists the impact of repeated bucket loading. The grease passages are redesigned and the sealing reinforced to keep out both mine dust and the humid rainwater that often hits Brazil’s tropical mining zones.

Our production covers quenching, drilling, final inspection, waterproof anti-rust treatment, and wooden case packing. We keep a photo record of everything – from lifting to installation to container loading. Every dimension is double-checked against confidential drawings. With a 2,000-hour annual workload, this heavy slewing bearing keeps the Z470 spinning reliably, no matter how tough the job.

Technical Highlights

  • Custom triple-lip seal design to prevent dust and moisture ingress
  • Induction-hardened raceway: 55–58 HRC surface, 3.5 mm case depth
  • External gear profile: module m=6, Z=168, 20° pressure angle
  • Load capacity: 680 kN axial, 135 kNm overturning moment
  • Grease refill interval extended from 80h to 200h with polyurea-based high-temp grease
  • Pre-assembly ultrasonic inspection and 360° torque test before shipment

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