HarmonicDrive Rotary Actuators RH /FLA Series

HarmonicDrive Rotary Actuators RH /FLA Series



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HarmonicDrive Rotary Actuators

HarmonicDrive RH /FLA Series
HarmonicDrive 旋轉型致動器 RH /FLA 系列 HarmonicDrive 旋轉型致動器 RH /FLA 系列 HarmonicDrive 旋轉型致動器 RH /FLA 系列
HarmonicDrive 旋轉型致動器 RH /FLA 系列
HarmonicDrive 旋轉型致動器 RH /FLA 系列
HarmonicDrive 旋轉型致動器 RH /FLA 系列

Excellent Technology Clusters in a Wide Range of Industries

HarmonicDrive® products are unique wave motion gearings that play important roles in robots,
semiconductor manufacturing systems, factory automation equipment...
as well as in aerospace equipment that foster the dreams of humanity.
We offer a variety of mechanical electronic products that bring about high precision motion
control in optical measuring equipment, medical equipment, printing machines and other systems.
Our products offer many advantages in the fields of industrial and scientific technology.
Harmonic Drive Systems Inc. is making every effort to develop supportive technologies for the
21st century, thereby contributing to the advancement of global technology.


High rotational and positioning accuracy, compact and light weight, high reduction ratio, high torque capacity,
non-backlash, high efficiency, silent operation


Driven by a unique operating principle applying metal elastodynamics and comprising only three basic parts (a wave generator, flexspline and a circular
spline), our HarmonicDrive wave motion gearing (registered trademark) excel with superb characteristics that are not found in other wave motion gearing


HarmonicDrive® Structure of HarmonicDrive® Unit (Component Type)


The Flexspline is a non-rigid, thin cylindrical cup with external teeth, with a slightly smaller pitch diameter than the Circular Spline. The bottom of the Flexspline is called the diaphragm, and is usually mounted onto the output shaft.

Wave Generator

The Wave Generator is a thin raced ball bearing fitted onto an elliptical hub serving as a high
efficiency torque converter, and is generally mounted onto the input shaft.

Circular Spline

The Circular Spline is a rigid ring with internal teeth of the same size as the Flexspline, but the
Circular Spline has two more teeth than the Flexspline and is generally mounted onto the housing.

Operating Principle 

There are three main components. The Flexspline is bent into an elliptical shape by the Wave Generator; and the teeth of the
long axis of the ellipse engage with the Circular Spline, whereas the teeth of the short axis are completely separated.
As the Circular Spline is fixed in place and Wave Generator (input) rotates in a clockwise direction, the Flexspline deforms elastically and the position where the gears mesh with the Circular Spline moves in turn. For each rotation of the Wave Generator, the Flexspline rotates backwards by only two teeth from its original position, or in other words in the reverse direction relative to the Wave Generator. This motion is generally retrieved as the output.


Tooth behavior and engagement

Unlike the motion of ordinary gears, the unique tooth behavior (operating principle) of the
HarmonicDrive® makes non-backlash motion possible, as well as infinitesimal angular feeding
(one-pulse feeding) and high positioning accuracy. More than 30% of all teeth simultaneously
engage in two locations in 180° symmetry, allowing for high torque capability.

RH Series

DC Servo Motors/Compact Cylinder Type

The DC servo actuator RH series is comprised of HarmonicDrive® components for precision motion control and a DC servo motor, featuring a high torque, high rotational accuracy and a compact design. The RH series DC servo actuators are best suited as positioning drive sources for machines and systems that require a more compact design.


FLA Series

DC Servo Motors/Ultra-flat, Ultra-light Type

The new ultra-flat, ultra-light brushless actuators combine our high-precision and high-performance reducers with a compact, high-output brushless DC motor.
FLA actuators are available with our high speed, high-efficiency HarmonicPlanetary® gearhead or with our high-precision,
high-torque HarmonicDrive® reducer.
We offer both 24VDC and 48VDC versions to work with battery-powered applications.