Principle of Harmonic Reducer
The harmonic reducer is composed of four basic components: a cup-shaped flexible gear, an elliptical wave generator, a rigid gear, and a cross bearing. The flexible gear is a thin-walled gear whose outer diameter is slightly smaller than the inner diameter of the rigid gear and can produce greater elastic deformation; the wave generator is an elliptical shape. The wave generator is installed in the flex gear to change its cross section from the original circle to the ellipse, so that the flex gear becomes an elliptical gear. The nearby gears are disengaged, and the flexible gear is continuously deformed when the wave generator rotates, so that the flexible gear and the rigid gear are continuously meshed and disconnected, and the cycle is repeated to realize the movement of the harmonic gear reducer.
Application of Harmonic Reducer
Harmonic reducers are widely used in aviation, aerospace, energy, navigation, shipbuilding, bionic machinery, commonly used ordnance, machine tools, instruments, electronic equipment, mining and metallurgy, transportation, lifting machinery, petrochemical machinery, textile machinery, agricultural machinery and medical equipment and other aspects. Especially in the servo system with high dynamic performance, the use of harmonic gear transmission shows its superiority. The power it transmits ranges from tens of watts to tens of kilowatts, but high-power harmonic gear drives are mostly used in short-term work sites.
Advantages of Harmonic Reducer
Consists of a rigid gear, a flexible gear, a wave generator and a cross bearing four parts, so the reducer has advantages of simple structure, few parts, small size and light weight. The volume and weight are reduced by more than 1/3 compared to other reducers. Due to the relatively large transmission ratio of the harmonic reducer structure, the reduction ratio of the commonly used double-wave harmonic reducer can reach up to 60,000. In addition, the harmonic reducer has high transmission accuracy and low noise, and the gear gap can realize zero backlash transmission. It has fewer parts and light weight, so the moment of inertia is small and the transmission efficiency is high.
Disadvantages of Harmonic Reducer
Because of the principle of harmonic deceleration, it can be known that the flexible gear must be continuously and periodically deformed when it is working, so it is prone to fatigue damage. At the same time, the flexible gear is a thin-walled part, and its ability to resist overload is relatively low. Therefore, some harmonic deceleration opportunities have a torque sensor to prevent overload. Moreover, the transmission starting torque is large, the manufacture of the flex-spline generator is difficult, and the maintenance is difficult. The lower limit of the transmission ratio is high, and the transmission ratio is generally not less than 35.