Electric servo-actuator 20S

rotarywith servo-motorplanetary gear

Introduction
The backlash-free planetary rotary actuator integrates a frameless internal-rotor torque motor, precision backlash-free planetary gearboxes, an absolute encoder and related components to form a compact rotary actuator unit. The drive unit is normally mounted externally, enabling high‑precision motion control for connected equipment. Compared with harmonic-drive solutions, this series uses high‑rigidity backlash‑free planetary gearboxes, providing increased stiffness, load capacity and bending‑moment resistance. Typical applications include machine‑tool rotary tables, precision medical devices, 5‑axis laser cutting systems and semiconductor equipment.

Features

• High precision and rigidity: precision anti‑backlash planetary reducers for tight positioning and increased bending stiffness.
• High torque at low speed: torque output optimized for low‑speed, high‑load operation.
• Compact integrated design: frameless torque motor embeds directly into the actuator to reduce overall package size.
• Precision control capability: built‑in high‑resolution absolute encoder supports micron‑level positioning and soft‑landing functions.
• Low inertia response: lightweight rotor and low‑friction structure improve dynamic response and reduce motion lag.

Specification
Models: 20S, 20T, 30S, 40S, 40T, 80S (AC‑220V)
Reduction ratios (examples): 91125/1331, 45
Rated torque: 180–820 N·m depending on model
Peak torque: 358–1780 N·m depending on model
Rated speed: 29–49 RPM; max speed up to 91 RPM
Positioning accuracy: Unidirectional ≤15–≤35 arcsec; Repeatability ≤2–≤10 arcsec
Motor electrical ranges: phase resistance 0.126–0.88 Ω (20°C); inductance 0.65–8 mH; Back‑EMF 40–55 Vrms/Krpm
Rotor inertia (no brake): 4.8×10^-4–5.8×10^-3 kg·m²
Mass (without brake): 9.2–24.5 kg
Diameter × length examples: ø146×147 mm to ø248×210.7 mm
Hollow shaft options: 20T ø32 mm; 40T ø46 mm; others: no hollow shaft

Technical characteristics

• Available models cover a wide torque and size range for integration into industrial rotary axes.
• Electrical and mechanical parameters are listed per model; contact sales for application‑specific data.
• Designed for compact integration where high stiffness, low backlash and precise positioning are required.
• Suitable for robotized positioning, rotary indexing, precision assembly and semiconductor handling.