Strain wave servo-gearbox FSG-II series

harmoniccoaxialkeyed bore

Introduction
The FSG-II strain wave gear (harmonic drive family) uses a cross-slider coupling wave generator. Cam-shaft bore dimensions are customizable to fit specific motor models. The input shaft connects to the wave generator inner bore via a keyed connection. Typical configuration: circular spline fixed at the base and flexspline as the output.

Key features

• Wave generator with integrated cam structure provides larger machining-tolerance allowance and self-aligning capability while maintaining required coaxial alignment.
• High torque capacity in an optimized compact design.
• Excellent rotational and positioning accuracy with low backlash (≤20 arc sec typical).
• Coaxial input and output with direct keyed input connection.
• Customizable cam-shaft bore to match motor interfaces; suitable for integration on robot arm end-effectors and sealed rotary tables.

Starting torque (unit: cNm) — reduction ratios / sample values
Reduction ratio | 11 | 14 | 17 | 20 | 25 | 32 | 40
Size 50 | — | 4.5 | 6.7 | 8.6 | 17 | 34 | 61
Size 80 | — | 3.1 | 4.4 | 5.4 | 10 | 21 | 39
Size 100 | — | 2.8 | 3.7 | 4.7 | 8.8 | 20 | 34
Size 120 | — | — | 3.4 | 4.2 | 8 | 17 | 31
Size 160 | — | — | — | 3.6 | 6.9 | 15 | 26

Design and permissible loads (per model)
FSG-14 | Design Mb 20 Nm | Instant permissible Mb max 40 Nm | Ft di 180 N / Ft max 320 N | Fa di 180 N / Fa max 320 N
FSG-17 | Design Mb 30 Nm | Instant permissible Mb max 60 Nm | Ft di 230 N / Ft max 400 N | Fa di 230 N / Fa max 400 N
FSG-20 | Design Mb 42 Nm | Instant permissible Mb max 80 Nm | Ft di 270 N / Ft max 480 N | Fa di 270 N / Fa max 480 N
FSG-25 | Design Mb 80 Nm | Instant permissible Mb max 160 Nm | Ft di 440 N / Ft max 770 N | Fa di 440 N / Fa max 770 N
FSG-32 | Design Mb 220 Nm | Instant permissible Mb max 440 Nm | Ft di 900 N / Ft max 1600 N | Fa di 900 N / Fa max 1600 N
FSG-40 | Design Mb 320 Nm | Instant permissible Mb max 650 Nm | Ft di 1000 N / Ft max 1750 N | Fa di 1000 N / Fa max 1750 N

Performance overview (examples)
Detailed performance matrix is provided per model and per reduction ratio, including rated torque at 2000 r/min (Nm), permissible peak torque at start/stop (Nm), permissible average-load torque (Nm), permissible momentary torque (Nm), permissible max input speed (r/min, grease), permissible average input speed (r/min, grease), backlash (arc sec), weight (kg) and design life (hours). Example entries:
Model 14 (50 ratio): Rated torque 7 Nm | Peak 23 Nm | Avg-load 9 Nm | Momentary 46 Nm | Max input speed 8500 r/min | Avg input speed 3500 r/min | Backlash ≤20 arc sec | Weight ≈0.51 kg | Design life 10000 h
Model 17 (50 ratio): Rated 21 Nm | Peak 44 Nm | Avg-load 34 Nm | Momentary 91 Nm | Max input speed 7300 r/min | Avg 3500 r/min | Backlash ≤20 arc sec | Weight ≈0.67 kg | Design life 10000 h
Higher models (20,25,32,40) show progressive increases in rated and peak torques, corresponding permissible speeds and masses; consult the full performance matrix in the product datasheet for values per configuration.

Technical specifications

• Series: FSG-II (strain wave / harmonic drive)
• Wave generator: integrated cam structure with cross-slider coupling
• Input connection: keyed connection between input shaft and wave generator inner bore
• Typical configuration: circular spline fixed at base; flexspline as output end
• Customizable cam-shaft bore to fit motor models
• Primary uses: robot arm end-effectors, sealed rotary tables and compact precision drives
• Available models: FSG-14, FSG-17, FSG-20, FSG-25, FSG-32, FSG-40
• Typical reduction ratios: 11, 14, 17, 20, 25, 32, 40 (additional ratios per model listed in datasheet)
• Backlash: ≤20 arc sec (typical)
• Permissible input speeds and design life vary by model and ratio — see datasheet for detailed tables