Harmonic gearboxes are widely used in robots, automated equipment, and precision transmission systems. They are characterized by their small size, high precision, and low backlash, but they also have very demanding requirements for the lubricating grease. Many field applications encounter a common problem:
After running for a period of time, phenomena such as grease thinning, grease splattering, grease leakage, or even dry friction may occur inside the gearbox, which may appear as "grease loss." However, the real cause is often not the gearbox itself, but rather the use of the wrong grease or operating conditions that exceed the grease's tolerance range.
First, high temperature is the most direct cause of grease loss. The internal structure of a harmonic gearbox is compact, with concentrated stress. Under high load and high speed, the local temperature inside can be much higher than the temperature measurement point on the outer shell surface. If a grease with a low dropping point or insufficient high-temperature resistance is used, oil separation, softening, and thinning will occur when the temperature exceeds the limit. The oil is thrown out of the meshing area, ultimately appearing as "loss".
The second reason is that the grease itself is incompatible with the harmonic gearbox. Ordinary grease or mineral oil-based grease will quickly break down its thickened structure in high-shear environments, causing it to thin and leak; at the same time, the oxidation rate accelerates at high temperatures, causing the grease to turn black, harden, or evaporate. Especially in high-stress areas like harmonic meshing, inferior grease simply cannot withstand the stress.
Third, incorrect grease filling is also a common problem. Many factories, for safety, overfill the gearbox, but this actually causes the grease to overheat, further raising the temperature and causing the grease to break down and leak out. Adding too little grease is also problematic, leading to insufficient lubrication, frictional heat, and accelerated grease failure. The appropriate filling amount is usually related to the equipment structure and rotational speed, and should not be increased arbitrarily.
Harmonic gearbox grease loss is mostly not due to equipment malfunction, but rather to incompatible grease selection. If you are experiencing problems such as grease splashing out, increased noise, widened gear backlash, or significant temperature rise, the most effective solution is to select a suitable high-temperature, shear-resistant grease based on your operating conditions. Baoxing provides matching solutions for various precision transmission systems and can offer sample testing .
