Installation principles of harmonic reducer gearbox

1.Main knowing about the harmonic reducer gearbox

A harmonic reducer gearbox is a high-precision, high-efficiency speed reduction device widely used in mechanical equipment, industrial automation, robotics, and other fields. Its core operating principle is based on harmonic transmission, which utilizes the elastic deformation and interlocking between a flexible wheel and an inner gear ring to achieve power transmission and speed reduction. The harmonic reducer primarily consists of three fundamental components: the drive shaft, the harmonic generator (including the wave generator and inner gear ring), the flexible wheel (elastic wheel), and the output shaft. The wave generator is typically an elliptical or similarly shaped component inserted into the interior of the flexible wheel via bearings.

2.Working principle of harmonic reducer gearbox

1.Harmonic Transmission: Since the number of grooves on the flexible wheel typically exceeds the number of cams on the wave generator, the flexible wheel rotates at a slower speed as the wave generator turns, achieving the reduction effect. Simultaneously, the elastic deformation and engagement between the flexible wheel and the inner gear ring ensure high transmission precision and rigidity.

2.Output Shaft Drive: When the flexible wheel begins rotating, the outer gear ring on the output shaft also starts rotating. The teeth on the outer gear ring mesh with the inner gear ring on the output shaft, causing the output shaft to rotate. Through this transmission mechanism, the harmonic reducer converts the high-speed rotation of the drive shaft into low-speed, high-torque rotation of the output shaft.         

3.Design advantages of harmonic reducer gearbox

1.Wide transmission ratio range:The transmission ratio of the single-stage harmonic reducer can be between 50-300, preferably between 75-250, the transmission ratio of the two-stage harmonic reducer can be between 3000-60000, and the transmission ratio of the complex harmonic reducer can be between Between 200-140000.

2.High load-bearing capacity:Harmonic gear transmission has a large number of meshing teeth at the same time, and a large number of teeth can bear load. The flexspline is made of high-strength materials, and the teeth are in surface contact. The load-bearing capacity is greater than that of other gear transmission reducers.

3.High transmission accuracy:Since the harmonic reducer has multi-tooth meshing, the errors are averaged under normal circumstances. Compared with ordinary gears of the same precision, the transmission accuracy of harmonic gears can be improved by about four times.

4.Smooth movement:No impact and low noise. The teeth mesh in and out with the deformation of the flexspline, gradually entering and exiting between the steel wheel teeth. During the meshing process, the tooth surfaces are in contact, the sliding speed is small, and there is no sudden change. Both sides of the gear are involved in the work. Because there is no impact phenomenon, the movement is smooth.

5.The ulnar side gap can be adjusted:In the meshing of harmonic gear transmission, the relationship between the flexspline and the steel gear teeth mainly depends on the maximum size of the wave generator shape and the tooth shape of the two gears. Therefore, the hysteresis of the transmission can be very small, and the wave can be changed slightly. The radius of the generator is used to increase the deformation of the flexspline so that the backlash is very small, and even backlash-free meshing can be achieved. 

6.High transmission efficiency:Due to the small number of moving parts and low meshing tooth surface speed of harmonic transmission, the flexspline gear teeth move uniformly radially during the transmission process. Therefore, even if the output speed is very high, the relative slip speed of the gear is still extremely low, so the gear Small wear and high accuracy (up to 69%-96%).

4.Installation principles of harmonic reducer gearbox

1.Precision Alignment Principles:Mounting surfaces must have a flatness within 0.01mm to prevent warping the rigid or flexible splines.The installation plane must be perpendicular to the axis within 0.01mm.Threaded or through-holes must be concentric with the axis within 0.1mm to ensure the wave generator remains centered within the flexspline.

2.Mechanical Engagement Principles:The wave generator must be inserted so that the flexspline and circular spline mesh symmetrically at 180°. Any deviation to one side leads to excessive vibration and rapid component fatigue.During assembly, the long axis of the elliptical wave generator must align precisely with the long axis of the flexspline's natural deformation.The wave generator should be securely fastened to the input shaft to prevent axial movement, which could shift the elliptical deformation zone away from the teeth.

3.Fastening and Sealing Principles:Screws must be tightened in a crisscross (diagonal) pattern in 4–5 incremental stages to ensure even pressure distribution.Use only Grade 12.9 bolts combined with threadlocker (e.g., Loctite 243) to prevent loosening under high-torque, high-frequency operation.Static seals or O-rings must be placed between the rigid wheel and the input mounting plane to prevent grease leakage, which is fatal to the system.

4.Lubrication Principles:Approximately 80% of the flexible wheel cavity should be filled with the manufacturer-specified grease.If the unit is installed with the output end facing downward (not recommended), the grease volume must be increased to fully cover the meshing gear surfaces.All new installations must undergo a test run at 100 RPM; any abnormal noise indicates a violation of alignment or lubrication principles.