ZF 305537 – Cup Springs for HBW100 ZF Marine Transmissions

ID 1232539

1-2 weeks delivery time

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ZF 305537 – Cup Springs for HBW100. Marine disc (cup) springs for ZF/Hurth HBW100 transmissions, controlling axial preload. Steel alloy, zinc anti‑corrosion coating. OD 60 mm (2.36"), ID 40 mm (1.57"), height 20 mm (0.79"), deflection limit 10 mm. Spring rate 5.5 N/mm. Supports 31 bar (450 psi) pressure, axial load ~54.4 kg (120 lbs), operating −40 °C to +150 °C (peak 150 °C/300 °F). Fatigue life 1,000,000 cycles, hardness 60 HRC. Oil/grease compatible, press‑fit, direct replacement for HBW100.

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ZF 305537 – Cup Springs for HBW100 Marine Transmission (OEM Disc Springs)

The ZF 305537 Cup Springs are precision‑machined disc (cup) springs developed for axial preload control inside ZF/Hurth HBW100 marine transmissions. Their role is to maintain stable bearing and clutch stack pressure, reduce friction losses, and extend drivetrain service intervals in high‑stress marine conditions.

Key technical characteristics:

Material: corrosion‑resistant, heat‑treated steel alloy (zinc‑plated anti‑corrosion protection)
Hardness: 60 HRC for high wear resistance
Fatigue life: 1,000,000 load cycles
Spring constant (rate): 5.5 N/mm
Max operating pressure: 31 bar (450 psi)
Temperature tolerance: −40 °C to +150 °C (−40 °F to 302 °F), peak 150 °C (300 °F)
Lubrication compatibility: gearbox oil or grease
Precise press‑fit alignment with minimal friction thanks to polished surface finish

Mechanical specifications:

Part number	ZF 305537
Spring type	Cup/Disc Spring (Needle/Tapered Bearing Preload)
Material grade reference	SAE 5160
Surface treatment	Zinc‑plated anti‑corrosion + saltwater‑resistant coating
Outer diameter (OD)	60 mm (2.36")
Inner diameter (ID)	40 mm (1.97")
Height	20 mm (0.79")
Thickness / profile height	20 mm total profile height
Weight	0.3 kg (0.66 lbs)
Spring rate	5.5 N/mm
Max axial load at deflection	54.4 kg (120 lbs)
Max pressure supported in system	31 bar (450 psi)
Max operating temperature	150 °C (300 °F)
Elastic modulus	210 GPa
Dynamic load rating	4,000 N
Fluid compatibility	Transmission oils, marine fluids, fuels (via coating resistance)
Installation	Press‑fit / direct replacement
Transmission compatibility	ZF/Hurth HBW100
Certification	ISO 9001:2015, CE
Service life target	Up to 5,000 operating hours / 10 years
Deflection limit (approx.)	10 mm (0.39")

Applications:

Marine transmissions ZF/Hurth HBW100
Drivetrain bearing and clutch axial preload control
Recreational and commercial vessels exposed to high torque and vibration
Saltwater and outdoor propulsion assemblies requiring stable axial tension

Operational benefits:

Stable axial preload preserves bearing and clutch stack alignment
Reduced friction thanks to tapered energy transfer in disc profile
Long fatigue life lowers replacement frequency
Corrosion‑resistant construction minimizes marine degradation
Lower drivetrain wear → extended gearbox lifespan
Minimal maintenance and precise fit reduce service downtime