The rotation movement comes from the input shaft, which can be a servo motor shaft. This is connected to an element called "harmonic wave generator", which has an elliptical shape and is surrounded by an elliptical ball bearing. When the axis rotates, the edge changes position, so it looks like a motion wave is being generated. The part is inserted into a flexible spline made of torsionally rigid but flexible material. The material absorbs this fluctuation by bending and forming an ellipse according to the rotation of the input shaft. The outer edge of this flexible spline has gear teeth suitable for transmitting high loads without any problems. In order to transmit these loads, the flexspline is installed in a circular spline, which is a circular gear with internal teeth. The outer ring is rigid, and its inner diameter is slightly larger than the main axis of the ellipse formed by the flexspline. This means that the circular spline does not assume the elliptical shape of the other two components, but simply meshes its inner teeth with the teeth on the outer flexspline, causing the flexspline to rotate.
The speed depends on the speed of the input shaft and the difference in the number of teeth between the flexspline and the circular spline. The number of teeth of the flexspline is less than that of the circular spline, so it can rotate in the opposite direction at a smaller rate than the input shaft. The reduction ratio is: (the number of flexspline teeth-the number of circular spline teeth)/the number of flexspline teeth. The difference in the number of teeth can be changed to adapt to different reduction ratios, thereby adapting to different professional needs and requirements of the harmonic gearhead. Contact us for more harmonic drive details.
Planetary reducer is also known as planetary gear reducer. The gear structure is composed of sun gear, planetary gear, outer ring gear, planet carrier and drive shaft, and it adopts rigid gears; planetary gear structure reducer is usually composed of multi-stage planetary gears. The deceleration is achieved by a large gear on the output shaft of the gear with a small number of teeth meshes. The reducer is a rigid drive device used for low speed and high torque.
The drive structure of the harmonic reducer is composed of three basic components: a fixed inner toothed rigid wheel, a flexible wheel, and a wave generator that radially deforms the flex wheel. The harmonic reducer is composed of a fixed inner tooth rigid wheel, a flexible wheel and a wave generator that makes the flexible wheel radially deform. It has the characteristics of high precision and good bearing capacity, compared with ordinary reducers.
The planetary reducer and harmonic reducer are mainly different in structure. The planetary reducer has rigidity, and the structure of the harmonic reducer adopts rigid and flexible gear meshing drive. Compared with planetary gearbox, harmonic drive has the advantages of higher precision, larger transmission ratio, small size, light weight, high transmission efficiency, no impact, and low noise.