ZR35 Slewing Drive Planetary Gearbox — Right-Angle Bevel-Planetary, 3-5 Stage

の EP-ZR35 answers the question engineers regularly face at the top of the ZR slewing drive series: what if you need near-ZR45 torque capacity but the ZR45 only offers three fixed gear ratios? The ZR35 resolves this by delivering 34,500 Nm continuous torque — 81% of the ZR45 rating — across more than 67 ratio configurations spanning three stage counts (3-stage, 4-stage, and 5-stage). For the vast majority of applications in the 27,500-34,500 Nm class, the ZR35 provides the precise ratio match that the ZR45 cannot.

The 5-stage configurations extend the ratio range to 4,460:1 for ultra-low-speed heavy positioning, while the 3-stage ratios at 43:1-108:1 provide high-speed, high-thermal-capacity slewing for continuous-duty port crane and mining equipment applications. Three torque tiers (34,500 / 34,000 / 27,500 Nm) accommodate the full ratio span with graduated de-rating at the highest reduction values.

✅ Field-Replaceable (On-Site)

❌ Factory Service Required

Heavy Port Cranes (30-60 Tonne Lifting Class)

Harbour mobile cranes, ship-to-shore feeder cranes, and floating cranes in the 30-60 tonne lifting class generate slewing torques of 25,000-34,000 Nm during full-load boom rotation. The ZR35 3-stage at ratios 53:1-100:1 delivers the high thermal capacity (25.5-26.0 kW) that continuous port operations demand, while the 67+ ratio options ensure the optimal motor-gearbox pairing without compromising to the nearest available ratio. Dual-drive arrangements using two ZR35 units can reach 69,000 Nm combined continuous for the largest feeder crane installations.

Mining Excavators and Draglines (50-80 Tonne)

Excavators and draglines in the 50-80 tonne class generate sustained slewing torques that fall between the ZR30 (32,000 Nm) and ZR45 (42,500 Nm) capacities. The ZR35 fills this gap precisely, providing 34,500 Nm continuous with a 2:1 peak-to-continuous ratio (64,500 Nm peak) that absorbs the aggressive shock loads from bucket strikes and emergency reversals. The EP-SE track drive series provides matching undercarriage propulsion for these machines.

Large Boring Machines and Foundation Equipment

Large-diameter bored piling rigs, diaphragm wall grab cranes, and cutter-soil mixing equipment require high torque at controlled low speeds for tool rotation and mast positioning. The ZR35 5-stage at ratios 463:1-2,113:1 provides the creep-speed rotation these heavy foundation machines demand, with the full 34,500 Nm available across the majority of the 5-stage ratio range. The IP67 sealing withstands the bentonite slurry, concrete wash, and groundwater inherent in foundation construction.

Included with Every Unit

Available on Request

When should I choose the ZR35 over the ZR30 or ZR45?

Choose the ZR35 when: (a) continuous torque requirement exceeds 32,000 Nm (the ZR30 maximum), or (b) the application needs more ratio flexibility than the ZR45 offers (3 fixed ratios). The ZR35 provides 81% of the ZR45 torque with 22 times more ratio options. If your torque falls below 32,000 Nm, the ZR30 at 58 ratios is a more compact and cost-effective solution. If torque must exceed 34,500 Nm or peak loads exceed 64,500 Nm, the ZR45 is the only option.

What is the expected lead time for the ZR35?

Standard lead time is 6-8 weeks from order confirmation. The 4-stage configurations are the most commonly produced and may ship in 5-6 weeks if component stock is available. Units requiring custom output pinions, classification society witnessed testing, or non-standard coatings should allow 10-14 weeks. Emergency replacement units can be expedited — contact our team directly to discuss accelerated production options.

Can I order replacement seals and brake discs directly?

Yes. Seal kits, breather valves, brake assemblies, and brake disc replacements are available as separate spare part orders. Quote the ZR35 serial number (engraved on the housing) and the component required. Seal kits typically ship within 1-2 weeks; brake assemblies within 3-4 weeks. We recommend keeping one seal kit and one breather valve per unit as on-site spares for remote or high-criticality installations.

Does Korea Ever-Power offer factory overhaul service for the ZR35?

Yes. Units returned for factory overhaul undergo complete disassembly, inspection, cleaning, and measurement against original manufacturing tolerances. Worn gears, bearings, and seals are replaced. The overhauled unit receives a full load test identical to a new unit and ships with a fresh documentation package. Typical overhaul turnaround is 4-6 weeks from receipt at our facility. The overhaul cost is typically 40-55% of a new unit price depending on the condition of the gears and housing.

Dual ZR35**3 at ratio 70.40 on a 45-tonne harbour mobile crane. We selected the ZR35 over the ZR45 specifically because we needed a ratio close to 70:1 and the ZR45 only offers 14.19, 43.43, and 109.70. The 70.40 ratio from the ZR35 table was an exact match for our hydraulic circuit design. Combined continuous torque of 68,000 Nm is well within our requirement. Documentation package passed our internal QA review and the port authority inspection without any issues.

Replacement slewing drive on a 65-tonne excavator. The previous drive had been in service for 9 years and was ready for overhaul. We compared the overhaul quote against a new ZR35 and the new unit was only 60% more than the overhaul cost with a full warranty. Installed and commissioned in two days. Oil analysis at 2,000 hours looks clean. We have ordered the spare seal kit and breather valve as recommended — keeping them in the machine toolbox so they are available if needed at the pit face.

Large-diameter bored pile rig, ZR35**5 at 691.88 ratio. The drive works well for our application and the torque delivery is smooth at very low speeds. The 4-star rating is because the 3D CAD model we received was for the 4-stage variant instead of the 5-stage we ordered. The correct model arrived four days later after we flagged it. A small mix-up but on a project where our structural designer was waiting for the model to finalise the crane base steel, the delay cost us a day of fabrication scheduling. Product itself has been faultless.