Rotary Actuators

RSF-Supermini Brushless Servo Actuator

Worlds smallest zero backlash servo actuators combining Harmonic Drive precision gears with brushless motor and encoder - small enough to fit inside a robotic finger

ModelRSF-Supermini
SeriesRSF Series
Global Stock Network Custom Gear Ratios Application Engineering STO Safety Compliant
RSF-Supermini product image 1
RSF-Supermini
Model

RSF-Supermini · 1 product image· Contact LVH for CAD files

Product Overview

The RSF-Supermini series are extremely compact servo actuators using zero backlash Harmonic Drive precision gears with brushless servo motor and incremental encoder. Available in sizes 3C and 5B with gear ratios 30 50 and 100. RSF-5B available with optional brake. Compatible with Mitsubishi MELSERVO-J4. Mass as low as 31g. EN60034-1 and EN60034-5 safety certified.

The RSF-Supermini is a fully integrated rotary actuator combining servo motor, harmonic gear reducer, encoders, servo electronics, and compact mechanical packaging in a single assembly.

📐
Outer Diameter
⚖️
Weight
🔩
Hollow Shaft
18 mm
💪
Max Torque
🔄
Max Speed
⚙️
Gear Ratios
🎯
Output Type
Integrated robot joint module

Rotary Actuator Architecture

Harmonic Drive rotary actuators integrate a precision strain wave gear with a brushless servo motor in a compact assembly. The hollow shaft design allows cables, pneumatic lines, or laser beams to pass directly through the axis of rotation.

🔩

Hollow Shaft Design

Central through-bore enables cable routing through the axis of rotation in robot joint designs.

⚙️

Zero Backlash Gear

Harmonic Drive strain wave gear provides zero backlash for precise bidirectional positioning.

Brushless Servo Motor

Integrated brushless motor optimised for high cycle duty in automation applications.

🎯

High Accuracy

Positioning accuracy better than 1 arc-min with high repeatability across the operating range.

🔄

High Torque Density

Compact housing delivers high peak torque relative to size and mass.

🔧

Direct Load Attachment

Output flange directly accepts loads without additional coupling or bearing hardware.

Typical Applications

The RSF-Supermini suits robot joint axes, index tables, semiconductor handling, laser beam steering, and precision positioning applications requiring compact hollow shaft actuation with zero backlash.

Key Specifications

Critical performance parameters at a glance

📊
RSF-3C and RSF-5B
Available Sizes
📊
30, 50, 100
Gear Ratios
📊
RSF-5B available with optional electromagnetic brake
Optional Brake
📊
Connects directly with Mitsubishi MELSERVO-J4 SSCNET III/H
Mitsubishi Compatible
📊
EN60034-1:2010 EN60034-5
Safety Standard
📊
DCJ-055-09 DDP-090-09 HA-680-4B-24 and third party drives
Compatible Drives
📊
0.03Nm
RSF-3C Ratio 30 Rated Torque
📊
0.07Nm
RSF-3C Ratio 50 Rated Torque

Technical Specifications

Overview

Available Sizes
RSF-3C and RSF-5B
Gear Ratios
30, 50, 100
Optional Brake
RSF-5B available with optional electromagnetic brake
Mitsubishi Compatible
Connects directly with Mitsubishi MELSERVO-J4 SSCNET III/H
Safety Standard
EN60034-1:2010 EN60034-5
Compatible Drives
DCJ-055-09 DDP-090-09 HA-680-4B-24 and third party drives

RSF-3C Performance

RSF-3C Ratio 30 Rated Torque
0.03 Nm
RSF-3C Ratio 50 Rated Torque
0.07 Nm
RSF-3C Ratio 100 Rated Torque
0.11 Nm
RSF-3C Ratio 100 Maximum Torque
0.3 Nm
RSF-3C Mass
31 g
RSF-3C Positioning Accuracy
600 arc-sec all ratios

RSF-5B Performance

RSF-5B Ratio 30 Rated Torque
0.18 Nm
RSF-5B Ratio 50 Rated Torque
0.29 Nm
RSF-5B Ratio 100 Rated Torque
0.44 Nm
RSF-5B Ratio 100 Maximum Torque
1.4 Nm
RSF-5B Mass Without Brake
66 g
RSF-5B Mass With Brake
86 g
RSF-5B Ratio 50 Positioning Accuracy
180 arc-sec
RSF-5B Rated Speed
150 rpm ratio 30 / 90 rpm ratio 50 / 45 rpm ratio 100

Product Attributes

Product Type
Supermini Brushless Servo Actuator
Sizes
RSF-3C 31g and RSF-5B 66g
Brake Option
Optional brake available on RSF-5B
Mitsubishi Compatible
MELSERVO-J4 SSCNET III/H
Unique Feature
Small enough to fit inside robotic finger
Safety
EN60034-1:2010 EN60034-5
Manufacturer
Harmonic Drive LLC

Industrial Applications

These rotary actuators are used in compact motion systems where motor, reducer, and actuator packaging need to be tightly integrated for reliable deployment.

🤖

Robot Axis Actuation

Used in robot joints and compact rotary axes where packaged actuation simplifies mechanical and electrical integration.

Robot jointsCompactIntegrated
🏭

Automation Modules

Fits automated handling, transfer, and tooling systems requiring a self-contained rotary motion solution.

AutomationHandlingRotary motion
📦

End-of-Arm Systems

Supports wrist, tool rotation, and other compact axes in end-of-arm and auxiliary robotic mechanisms.

EOATWrist axisCompact
🔬

Precision Equipment

Useful in inspection, alignment, and specialist machinery where packaged rotary performance helps reduce integration effort.

InspectionAlignmentPrecision
🧩

OEM Motion Platforms

Helps OEMs build cleaner motion platforms by reducing the number of separate drive-train components.

OEMIntegrated motionSimplified design
🚚

Mobile & Service Robotics

Supports compact rotary motion subsystems in robots that need efficient packaging and robust mechanical integration.

Service robotsMobile systemsCompact actuation
Customization Available

Factory Modification & Custom Sourcing

This product supports custom configurations and equivalent sourcing

Available Modifications

  • Torque and speed ratio customization
  • Mounting interface modifications
  • Connector and wiring specifications
  • Housing and enclosure options

Sourcing Options

  • Standard product sourcing
  • Equivalent product identification
  • Replacement part sourcing
  • Volume pricing (MOQ may apply)

Request Pricing & Availability

Submit an RFQ for standard products, custom configurations, or equivalent alternatives

Expert Answers

Frequently Asked Questions

Technical answers sourced from engineering specifications and integration guides.

The RSF-Supermini series are extremely compact brushless servo actuators with Harmonic Drive gears and incremental encoder. Available in sizes 3C and 5B with mass as low as 31g.

Have a technical question not answered above?

Our application engineers review every RFQ and respond with specification-matched recommendations.

Ask an Engineer