Planetary Gearboxes

Key Features

• check_circleModular, customizable design - multiple stages, gear ratios, lengths, shafts, and mounting options
• check_circleCompact and lightweight footprint for space-constrained applications
• check_circleExceptional efficiency - precision-machined components minimize energy loss
• check_circleLow backlash and high accuracy for positioning and motion-control tasks
• check_circleDurable and reliable - evenly distributed forces reduce wear under heavy or repetitive loads
• check_circleHigh torque density in a compact cylindrical form factor

Configuration Options

• settingsSingle-stage and multi-stage reduction ratios
• settingsPrecision levels P0 (high precision), P1, and P2 (standard backlash)
• settingsMultiple frame sizes from 042 through 220
• settingsInput shaft adapters for servo, stepper, BLDC, and PMDC motors
• settingsCustom shaft lengths, flange patterns, and mounting orientations
• settingsRight-angle output with SBR Series for compact machine layouts

SB Series - High-Precision Planetary Gearboxes

The SB Series is a high-precision planetary gearbox line designed for servo motor applications. Available in frame sizes 042, 060, 090, 115, 142, 180, and 220 with reduction ratios from 3:1 to 100:1, SB reducers deliver rated output torques from 19 Nm (042SB) to 1,140 Nm (220SB) depending on ratio and frame size.

• arrow_rightSuper precision backlash P0: ≤1 arcmin (3:1–10:1 ratios)
• arrow_rightPrecision backlash P1: ≤3 arcmin
• arrow_rightStandard backlash P2: ≤5–7 arcmin
• arrow_rightRated input speed: 3,000 rpm (standard) / 6,000 rpm (high speed)
• arrow_rightEfficiency ≥97% (single stage, 3:1–10:1)
• arrow_rightProtection IP65, synthetic grease lubrication

SBR Series - Right-Angle Planetary Gearboxes

The SBR Series combines a planetary reduction stage with a right-angle bevel output box, enabling compact 90° power transmission for space-constrained machine layouts. Frame sizes 060 through 220 with ratios from 3:1 to 200:1.

• arrow_rightRight-angle output with integrated bevel stage
• arrow_rightSuper precision backlash P0: ≤4 arcmin
• arrow_rightPrecision backlash P1: ≤6–7 arcmin
• arrow_rightStandard backlash P2: ≤9 arcmin
• arrow_rightRated output torque up to 2,000 Nm (220SBR, low ratios)
• arrow_rightEfficiency ≥94–97% depending on ratio range

Economy Series Planetary Gearboxes

The Economy Series delivers cost-effective planetary reduction for applications where budget and volume matter without sacrificing quality or precision.

• arrow_rightLow cost: approximately half the cost of comparable manufacturers without sacrificing quality or precision
• arrow_rightLow noise: 58–60 dB
• arrow_rightHigh efficiency: 97%
• arrow_rightHigh torque: compact design with outstanding load capacity
• arrow_rightFlexible integration: compatible with PMDC, BLDC, BLDC servo, and stepping motors
• arrow_rightModular design: standardized sizes with multiple stages and gear ratios
• arrow_rightCustom manufacturing available to fit specific requirements

Downloads

FAQ

What is the difference between SB and SBR Series gearboxes?

SB Series provides inline (coaxial) output for standard servo motor mounting. SBR Series adds a right-angle bevel output stage for applications requiring 90° power transmission in a compact envelope.

Which motors can mount to SEI planetary gearboxes?

SEI planetary gearboxes accept servo motors, stepping motors, BLDC motors, and PMDC motors through standardized input adapters. Economy Series units are specifically designed for flexible integration across these motor types.

What backlash options are available?

SB Series offers P0 (≤1 arcmin), P1 (≤3 arcmin), and P2 (≤5–7 arcmin) precision levels. SBR Series offers P0 (≤4 arcmin), P1 (≤6–7 arcmin), and P2 (≤9 arcmin). Contact SEI to select the appropriate level for your positioning requirements.