Laifual Harmonic drive (harmonic drive, harmonic gearbox, harmonic reducer) mainly consists of three parts. Which are wave generator, flex spline, cicular spline. Our harmonic drive has the characteristics of zero-backlash, low-temperature rise, low starting torque, high reliability, high load capacity, long lifetime, big speed ratio, small size, etc. Laifual drive is a top manufacturer for harmonic drive. With more than 10 years R&D experience.

LS Series

The LS cup type features a flexspline with external gear teeth in the shape of a cup. Available options include: standard, high-torque, ultra-flat, lightweight.

  • LSS High Precision Harmonic Gearbox

    LSS High Precision Harmonic Gearbox

    LSS series adopts our newest developed 'LS' tooth profile, equipped to support external loads, featuring high rigidity cross roller bearings, making it a combination product that is easy to operate.

  • LSN Light Weight Harmonic Drive

    LSN Light Weight Harmonic Drive

    LSN series is the lightweight product line, designed to reduce the weight of the mechanical equipment itself and facilitate the lightweight construction of industrial robots. It enables higher speeds and increased payload capacity for industrial robots.

  • LSG High Torque Harmonic Drive

    LSG High Torque Harmonic Drive

    LSG series harmonic reducer employs a cup-shaped standard barrel structure for its flexible wheel, specifically developed for high-torque applications. With torque-bearing capacity surpassing 30% compared to the LSS series, it boasts an enhanced lifespan of over 43%, striving for high load capacity and reliability.

  • LSD Shorten Thin Harmonic Gearbox

    LSD Shorten Thin Harmonic Gearbox

    LSD series harmonic reducer features an ultra-thin cup-shaped structure, inheriting the excellent performance of traditional products while showcasing bold design innovations.

  • LFS Ultra Flat Harmonic Gearbox

    LFS Ultra Flat Harmonic Gearbox

    LFS series offers an ultra-flat harmonic actuator design, ensuring compatibility with space-constrained applications. It ensures smooth and precise motion control, enhancing overall performance.

LH Series

The LH hat type features a brim that looks very similar to a silk hat, hence the name. The brim acts as a perfect mounting surface, leaving a large through hole.

  • LHT High Precision Harmonic Gearbox

    LHT High Precision Harmonic Gearbox

    LHT series features a hollow flanged barrel structure, with a compact overall design and sleek, simple construction. The flexible wheel and rigid wheel are connected by high rigidity cross roller bearings, making it an easily operated modular product.

  • LHN Light Weight Harmonic Gearbox

    LHN Light Weight Harmonic Gearbox

    LHN Series features internal support bearings and a fully sealed structure, ensuring easy installation. Ideal for applications requiring umbrella gears or synchronous belt drives at the input end.

  • LHG High Torque Harmonic Gearbox

    LHG High Torque Harmonic Gearbox

    LHG series harmonic reducer features a hollow flanged barrel structure, with a compact overall design, developed specifically for high-torque applications.

  • LHD Shorten Thin Harmonic Gearbox

    LHD Shorten Thin Harmonic Gearbox

    LHD series features a flex spline with a flanged ultra-short tube structure. The axial length is reduced by 50% in the LHD-I model and by 15% in the LHD-III model.

LS full series display video


As a reducer, the harmonic gear reducer is often in status as the wave generator drives, the circular spline is fixed, and the flex spline is output end.

When the harmonic wave generator is put inside of the flex spline, the flex spline is forced into an elliptical shape causing the flex spline teeth to engage with the tooth profile of the circular spline along the major axis of the ellipse, with the teeth completely disengaged across the minor axis of the ellipse.

The rotation of the wave generator makes the flex spline deform continuously, the teeth change operating state in the process of engagement and disengagement, thus the power harmonic drive transmission between wave generator and flex spline is realized.


Harmonic gear reducer has three basic components: a wave generator,a flexspline and a circular spline.

  • 01

    Wave Generator

    The Wave Generator, a high-efficiency torque converter featuring a precisely machined elliptical ball bearing on an elliptical hub, connects directly to the motor shaft and serves as the main input for the gear assembly. It is typically used with a servo motor in applications needing controlled motion or torque transmission.

  • 02


    The Flexspline, made from alloy steel into a thin cylindrical cup with external teeth at its open end, adjusts to an elliptical shape when the Wave Generator is inserted.

  • 03

    Circular Spline

    The Circular Spline comprises a sturdy ring with internal teeth. As the gear is assembled, it meshes with the teeth of the Flexspline along the major axis of the Wave Generator ellipse. This interaction resembles an ellipse inscribed concentrically within a circle. From a mathematical perspective, an inscribed ellipse intersects a circle at two points. Nevertheless, due to the finite height of the gear teeth, there exist two regions of tooth engagement instead of just two points. Featuring two additional teeth compared to the Flexspline, the Circular Spline is affixed to the gear housing.



  • What is a harmonic drive box?


    A harmonic drive box is a type of gear system that produces high reduction ratios in a compact size. It uses the mechanics of a flexible element deforming to transmit motion and achieve high precision and torque.

  • How does a harmonic gear box work?


    A harmonic gear box works by using a circular spline, flexspline, and a wave generator. The wave generator deforms the flexspline into an elliptical shape, which then engages with the teeth of the circular spline at two points, providing a high reduction ratio through the difference in tooth count between the engaged elements.

  • What are the main components of a strain wave drive?


    The main components are the circular spline (fixed outer ring), the flexspline (flexible inner ring with fewer teeth), and the wave generator (an elliptical disc that fits inside the flexspline).

  • What are the advantages of using harmonic/harmonic drive boxes?


    Strain wave/harmonic gearboxes offer high precision, zero backlashes, high torque capacity, compact size, and lightweight. They are also known for their excellent positional accuracy and repeatability.

  • What applications are harmonic-type drives used in?


    They are used in applications requiring high precision and reliability, such as Robotics &Automation, Aerospace, Machine Tools, Medical Equipment, Semiconduct tor Equipment, Communication Equipment, Logistics.

  • How do you select a strain wave drive for a specific application?


    Selection depends on factors like torque requirements, desired reduction ratio, space constraints, load capacity, and environmental conditions. It's essential to consult with manufacturers or experts to choose the appropriate model.

  • What are the different types of harmonic drive boxes?


    Cup-type Gearboxes
    Hat-type Gearboxes


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