Description
ZF IRM 350.1 4.5 Gearbox
The ZF IRM 350.1 4.5 (specifically featuring a ~4.536:1 reduction ratio) is a heavy-duty marine reverse-reduction transmission. It handles power ratings typically up to roughly 372 kW (498 hp) at 1800 rpm (and higher limits depending on light-duty or commercial duty classifications), utilizing hydraulically actuated multi-disc clutches designed for commercial or large pleasure craft applications.
Key Specifications
- Manufacturer: ZF (Friedrichshafen)
- Model: IRM 350.1 (IRM 350 series)
- Gear Ratio: 4.536:1 (approx. 4.5:1 reduction)
- Power Capacity: ~372 kW / 498 hp (at 1800 RPM base reference)
- Clutch Type: Hydraulically actuated multi-disc system
Core Design Features
- Reduction & Reversal: Built for smooth ahead, neutral, and astern operations with matched capacity in both directions.
- Helical Gearing: Case-hardened, precision-ground gear teeth engineered for quiet operation and long service life.
- Thrust Bearing: Integrated output shaft thrust bearing sized to absorb maximum propeller thrust in forward and reverse.
- Cooling & Filtration: Equipped with integrated oil cooler connections and a replaceable oil filter element
Crucial Engineering Characteristics
- Full Power Contra-Rotation: The transmission handles equal continuous duty capability in both forward and reverse output rotations. This makes it perfectly compatible with twin-screw engine setups without needing specialized left- or right-hand gear layouts
- Integrated Hydraulic Control: It utilizes an integrated oil pump, a mechanical or electronic control valve block, and multi-plate oil-actuated clutches
- Auxiliary Equipment: Systems generally come configured with an external saltwater-cooled copper-nickel bundle oil heat exchanger to regulate high thermal loads
