A harmonic gear is a unique mechanical gearing system that allows for very high reduction ratios in a compact and lightweight package. Compared to traditional gear systems (such as helical gears or planetary gears), it can achieve up to 30 times higher reduction ratios in the same space. Additionally, it features zero backlash, high torque, accuracy, and reliability. Therefore, this gear system can be used in a variety of applications, including robotics, aerospace, medical machinery, milling machines, manufacturing equipment, and more.
The open end of the cup is flexible, but the closed end is quite rigid, so we can use it as the output and connect the output flange to it. The flex spline has external teeth at the open end of the cup. On the other hand, the circular spline is a rigid ring with internal teeth. The circular spline has two more teeth than the flex spline, which is a crucial design aspect of the harmonic drive system. Therefore, when we insert the wave generator into the flex spline, the flex spline takes the shape of the wave generator.
When the wave generator rotates, it causes radial deformation at the open end of the flex spline. The wave generator and flex spline are then placed inside the circular spline, meshing the teeth together. Due to the elliptical shape of the flex spline, the teeth only mesh in two regions on opposite sides of the flex spline, spanning the major axis of the ellipse produced by the wave generator.
As the wave generator rotates, the flex spline teeth that mesh with the circular spline will slowly change position. Due to the difference in the number of teeth between the flex spline and the circular spline, every 180-degree rotation of the wave generator will cause the flex spline to rotate backward slightly relative to the wave generator. In other words, with each 180-degree rotation of the wave generator, the flex spline teeth that mesh with the circular spline will advance by only one tooth. Thus, when the wave generator completes a 360-degree rotation, the flex spline will change position or advance by two teeth.
Additionally, harmonic reducers are widely used in aerospace, medical devices, precision instruments, and other fields. For instance, in satellites, harmonic drives can be used to adjust the angle of solar panels to achieve optimal solar energy collection efficiency. In medical devices, harmonic drives can control the movements of surgical robots, improving the accuracy and safety of surgeries.
