Strain wave gear reducer FSG-II

harmoniccoaxialrobot flange

Product overview
The FSG-II harmonic drive (strain wave gear) is a compact, high-precision reducer family designed for space-constrained industrial applications. HONPINE began series production of harmonic reducers in 2018 and has optimized tooth profiles and structural variants to cover a wide torque range (approx. 1 Nm to 2000 Nm). Core components are the flexspline, circular spline and wave generator, enabling high reduction ratios in a lightweight package.

Main features

• Only three core components: flexspline, circular spline, wave generator.
• High reduction ratios by tooth-count difference and wave deformation; double-wave options for improved meshing.
• Compact, low‑profile designs suitable for robot end-effectors, sealed rotary tables and other confined assemblies.
• High torque transmission and fine positioning due to multiple-tooth engagement.
• Structural variants: sealed flange, hollow shaft, top-hat (ultra-short), cup-type (ultra-compact), differential and mini-series.

Standard FSG series
FSG series covers multiple sizes (FSG-14, -17, -20, -25, -32, -40) with defined reduction ratios (11, 14, 17, 20, 25, 32, 40) and documented torque, axial/radial load and speed limits. Typical options include integrated wave generators with cross-slider coupling, cam-type wave generators and variants with integrated high-rigidity bearings to ease motor coupling and assembly.

Flange harmonic drives
Flange-mounted units are prepared for direct motor connection: motor-bore and mounting flange machining can be factory-configured; many flange units are factory-filled with specialty grease and provide sealed interfaces for robust operation in demanding environments.

Extra-large / high-torque units
Large-size FCG / FHG families address high-torque requirements (examples: FCG-45-AJ, FHG-65-AH). These designs offer increased rigidity, large hollow bores for cable or lead-screw routing and options for synchronous pulley or direct motor integration.

Mini / micro harmonic drives
CSF-mini and SHD-mini series deliver ultra-compact, lightweight and high-precision solutions for small actuators. Multiple input/output configurations (shaft, bore, flange) and compact bearing choices (four-point contact, micro roller) support integration with small motors and modules.

How the harmonic gear operates (FAQ)
The wave generator elastically deforms the flexspline producing an elliptical profile so the flexspline teeth sequentially engage the circular spline teeth. The tooth-count difference (ΔZ) creates the reduction ratio; double-wave transmissions (ΔZ = 2) are used to improve uniformity and wear characteristics.

Reduction ratio calculation (FAQ)
Key relations:

• Flexspline output (circular spline fixed): i = Zf / (Zg − Zf) ≈ Zf / ΔZ
• Circular spline output (flexspline fixed): i = Zg / (Zg − Zf) ≈ Zg / ΔZ

Customization and selection
HONPINE supports customization of cam bore, motor mounting features, bearing choices and shaft bores when standard models do not match requirements. For selection, define: application, installation orientation, required reduction ratio, input/output speeds, rated and peak torque, accuracy, mounting method and envelope constraints.

Technical specifications / key data

• Core components: flexspline, circular spline, wave generator.
• Torque range: ~1 Nm to 2000 Nm across families.
• Typical reduction ratios: 11, 14, 17, 20, 25, 32, 40 (and derived ratios).
• Structural variants: sealed flange, hollow shaft, top-hat (ultra-short), cup-type, differential, mini.
• Bearings: integrated cross roller bearings in many series; compact four-point contact bearings in mini series.
• Backlash: typically ≤20 arcsec (mini variants may be ≤40 arcsec depending on model).
• Lubrication: many flange models are factory-filled with specialized grease.