Spiral bevel angle gearbox NA-serie

flangehollow-shaftcast iron

Overview
NEFF NA series bevel gearboxes are mount-on bevel reducers designed for redirecting and distributing drive torque in lifting and industrial drive systems. They feature a grey cast iron housing, hardened spiral bevel gears lapped in pairs and robust roller bearings for high load capacity and accurate transmission. Spiral bevel geometry provides improved tooth overlap and bending resistance, making the units suitable for heavy-duty and shock-loaded applications.

Transmission ratios

• Standard ratios available: 1:1
• Other common ratios on request: 1.5:1, 2:1, 3:1, 4:1, 5:1, 6:1

Efficiency
Typical gearbox efficiency ranges from 94% to 98% depending on speed, installation position, sealing and lubricant. Efficiencies refer to rated power. In certain installation positions bevel gears may operate immersed in oil; for larger sizes and high peripheral speeds, churning losses should be considered. Note that start-up efficiency is lower than running efficiency — take increased breakaway torque into account in drive design.

Preferred direction of rotation
NEFF gearboxes are reversible. The spiral direction of the gear set combined with rotation direction influences axial loads. If the pinion is driven against its spiral direction (viewed from the shaft end toward gearbox centre), axial force acts outward, slightly separating the gear set and reducing noise by approximately 1–2 dBA. NEFF pinions are manufactured with left-hand spiral; the preferable rotation is clockwise.

Lubrication
Gearboxes are delivered prefilled with oil and are maintenance‑free under normal operating conditions. For extreme duty or extended service life requirements, an oil change is recommended after approximately 15,000 operating hours.

Designs, mounting and installation
Three standard designs are available with up to 22 auxiliary variations for special mounting or power distribution needs. Units can be supplied with hollow shaft for direct mounting or with a plug shaft for use as distributor gearboxes. They can be installed in any position; covers and flanges are typically supplied with mounting holes.

Applications
Typical applications include lifting systems, conveyor drives, heavy machinery where smooth running, high transmission accuracy and shock-load capability are required.

Technical specifications

• Housing material: grey cast iron
• Gear type: hardened spiral bevel gears, lapped in pairs
• Toothing: spiral / arc‑shaped teeth for higher bending resistance
• Bearings: dimensioned roller bearings
• Standard transmission ratios: 1:1; other ratios available
• Designs: 3 standard designs; 22 auxiliary variations possible
• Efficiency: 94–98% (depends on conditions)
• Direction of rotation: reversible; preferable clockwise (pinion left‑hand spiral)
• Installation positions: all positions
• Mounting: cover and flanges generally with mounting holes; various mounting options
• Lubrication: delivered filled with oil; maintenance‑free under normal use; recommended oil change ≈ 15,000 h under severe requirements
• Max. input speed: consult NEFF (typical limit for certain sizes: up to 1500 min-1)

More information
Detailed product datasheet and CAD models are available in the NEFF catalog. For selection, mounting details or special variants please consult NEFF technical documentation.