Harmonic Drive Gearbox – Complete Introduction and Analysis
The Harmonic Drive Gearbox, also known as a Strain Wave Gearbox, is irreplaceable in applications requiring high precision, compact size, and low load.It is widely used in collaborative robots, servo systems, precision positioning and scanning equipment, aerospace, defense, and other high-precision systems.Thanks to its zero backlash, high reduction ratio, lightweight design, high positioning accuracy, and excellent repeatability, the harmonic drive has become an essential precision transmission solution in many advanced fields.
Basic Structure of a Harmonic Drive Gearbox
A harmonic drive mechanism mainly consists of three core components: the Wave Generator, Flexspline, and Circular Spline.
Wave Generator
Composed of a flexible bearing and an elliptical cam, the wave generator is typically mounted on the input side of the gearbox.
The inner ring of the bearing is fixed to the cam, while the outer ring deforms elastically into an elliptical shape through the rolling elements.
Flexspline
A thin-walled, flexible cup-shaped component with external teeth. It is usually mounted on the output side of the gearbox.
Circular Spline
A rigid ring with internal teeth, typically having two more teeth than the flexspline and fixed to the housing.
Operating Principle of the Harmonic Drive
In a standard harmonic drive configuration, the wave generator acts as the input, the circular spline is fixed, and the flexspline serves as the output.When the wave generator is inserted into the flexspline, it deforms the flexspline into an elliptical shape.At the major axis of the ellipse, the teeth of the flexspline and circular spline are fully engaged;at the minor axis, the teeth are completely disengaged.Between these two axes, the teeth are either engaging or disengaging.
As the wave generator rotates continuously, the flexspline undergoes a cyclic deformation, causing its teeth to progressively mesh and unmesh with those of the circular spline.This results in a relative motion between the wave generator and flexspline, thereby achieving motion transmission and speed reduction through the so-called strain wave effect.
For a detailed explanation of the harmonic drive principle, please refer to the following article on the HONPINE official website:
Features of the Harmonic Drive Gearbox
High Precision
Multiple teeth are engaged simultaneously at two symmetrical positions (180° apart), which averages out pitch errors and ensures exceptionally high positioning and rotational accuracy.
Large Reduction Ratio
A single-stage harmonic drive can achieve reduction ratios of i = 30–500 with a simple structure consisting of only three coaxial components.
High Load Capacity
The tooth engagement is surface contact, and multiple teeth are engaged simultaneously, resulting in low unit stress and high torque capacity.
Compact and Lightweight
Compared with conventional gear mechanisms, harmonic drives offer significant size and weight reduction, enabling miniaturization and lightweight designs.
High Transmission Efficiency and Long Service Life
Smooth Operation with Low Noise and Minimal Vibration
Classification of HONPINE Harmonic Drive Gearboxes
HONPINE harmonic drives are mainly categorized into five series
Direct Drive Harmonic Drive
Hollow Type Harmonic Drive
Input Shaft Harmonic Drive
Ultra-Thin Harmonic Drive
Mini Harmonic Drive
Each type is optimized for different installation configurations, transmission interfaces, spatial orientations, weight requirements, and functional demands—ensuring the most suitable solution for every application.
If you have previously used other brands such as Harmonic Drive AG, LeaderDrive, or Nabtesco, you can share your model information with us for direct replacement.
HONPINE’s technical team will provide one-on-one selection and customization support.
HONPINE Harmonic Drive Gearbox Specifications：
Reduction Ratio Range: 30 – 160
Rated Torque Range: 0.06 – 385 N·m
These specifications cover the majority of industrial applications, and custom designs are available for special requirements.
Contact HONPINE for more information about our Harmonic Drive Gearbox solutions and discover how we can support your precision transmission needs.
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How to Select the Most Suitable Harmonic Drive Gearbox Based on Specific ApplicationsWhen mechanical engineers select a harmonic drive gearbox, they typically evaluate its performance characteristics and operating environment, confirming the most appropriate model through drawings and key specifications.- HONPINE Develops World's First 1.2cm CS Micro Harmonic Drive Designed for Humanoid Robot FingersHONPINE has pioneered a micro harmonic drive specifically engineered for humanoid robot fingers, replacing bulky traditional ball screw designs. A single harmonic drive now powers each joint, enabling ultra-precise and agile finger movements.
HONPINE Harmonic Drive’s Backdriveability Enables Technological Breakthroughs in Multiple FieldsTo achieve safe, compliant, and flexible human-robot collaboration—ensuring environmental adaptability and operator comfort—merely obtaining torque feedback from the robot/environment is insufficient. High backdrivability in robots/integrated joint modules is often essential. HONPINE harmonic drives provide new opportunities in human-robot interaction through superior backdrivability.- Ultra-Small Harmonic Drive – Precision Manufacturing with High-End MaterialsHONPINE’s SHD and CSF series of ultra-small harmonic drives mark a breakthrough in compact harmonic drive technology. Comparable in size to a paperclip, these drives are available in four models (03, 05, 08, and 11), each offering multiple input/output configurations (shaft and flange) and gear ratios (30, 50, 80, and 100) to meet diverse torque and speed requirements—resulting in dozens of product variations.
- HONPINE Establishes Ultra-Fine Grain Harmonic Reducer R&D and Production Center, Aiming to Surpass Japan's Harmonic Drive in PrecisionTo meet the growing demand for higher precision in harmonic reducers from customers in CNC, humanoid robots, medical equipment, and other application fields, HONPINE has established an ultra-fine grain R&D and production center. The center plans to adopt ultra-fine grain production technology to enhance the precision and rigidity of harmonic reducers.
Cup-Type Harmonic Drive Effectively Addresses Short Lifespan Issues of Harmonic DriversIn industrial robots, harmonic drives are widely used in joint transmission systems due to their high precision, high torque transmission, and smooth operation. These characteristics make harmonic drives an ideal choice for applications requiring precise control and high performance, such as industrial robots, aerospace equipment, and precision instruments. To solve the problem of fatigue failure and short lifespan of the flexspline—a critical component in harmonic drives—HONPINE has designed a cup-type harmonic drive.- Top-Hat Type Harmonic Drive Reducer: Innovative Design Prolongs Service LifeThe harmonic drive reducer is a high-performance reducer featuring a compact structure, large transmission ratio, light weight, minimal backlash, and high transmission accuracy. It is widely used in high-precision fields such as industrial robotics, medical equipment, aerospace, and intelligent manufacturing. As a key core component of industrial robots, its performance directly affects motion control accuracy, operational stability, and energy efficiency. The top-hat type harmonic drive reducer is developed based on the conventional harmonic drive reducer, with enhanced rigidity and extended service life.
The A-Z of Harmonic Reducers: Your Go-To Resource for Precision Mechanics1.What is a harmonic reducer?
The harmonic reducer was invented by C.W. Musser of the United States. It is a unique mechanical gear system characterized by zero backlash, high precision, high torque, and a high reduction ratio in a compact and lightweight structure.- Mini Harmonic Drive Selection Guide: Specification, Brand, ClassificationWith the development of science and technology, the application scope of robots is becoming wider and wider, including industrial and service levels. Robots in different fields require different reducers. For example, service robots require a small size and a certain load-bearing capacity to ensure the operation of the robot. HONPINE mini harmonic drive began to be developed based on market demand, and has been verified by the market and can be mass-produced.
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