Robots, as intelligent devices capable of performing various tasks on behalf of humans, have been widely used in industrial production, healthcare, military defense, and other fields. Among them, the joint transmission system is the core of robot movement, and the reducer, as an important component of the joint transmission system, plays a crucial role in the robot's performance and technical level. Currently, the commonly used reducers in robots are mainly harmonic reduction gears and ordinary reducers.
Structure Comparison
The harmonic reduction gear is a high-precision reducer based on the principle of flexible gears. Its mechanism consists of three main components: a rigid gear, a harmonic generator, and a flexible gear. During operation, the rigid gear is fixedly mounted, and each tooth is evenly distributed around it. The flexible gear, with an external gear shape, rotates along the internal teeth of the rigid gear.
The flexible gear has two fewer teeth than the rigid gear, so it rotates two teeth in the opposite direction for every full rotation of the rigid gear. The harmonic generator has an elliptical profile, with balls installed on it to support the flexible gear, driving the flexible gear to rotate and plastically deform. When rotating, only a few teeth at the elliptical ends of the flexible gear mesh with the rigid gear, allowing the flexible gear to rotate freely to a certain angle relative to the rigid gear.
On the other hand, an ordinary reducer consists of gears, bearings, and a housing. Compared to the harmonic reduction gear, the structure is simpler, but the harmonic reduction gear offers higher precision and reliability due to its complex structure.
Transmission Efficiency Comparison
The transmission efficiency of the harmonic reduction gear is usually above 90%, while that of the ordinary reducer is around 80%. This is because the harmonic reduction gear uses the flexible gear transmission principle, reducing energy loss during transmission.
Precision Comparison
The precision of harmonic reduction gears is typically below 1 arc-minute, while that of ordinary reducers is around 5 arc-minutes. This is due to the flexible gear transmission principle adopted by harmonic reduction gears, resulting in higher precision and repeatability.
Load Capacity Comparison
The load capacity of harmonic reduction gears is generally over 1000 N.m, whereas ordinary reducers have a load capacity of around 500 N.m. This higher load capacity is again due to the use of flexible gears in harmonic reduction gears.
High Precision
Harmonic reduction gears, using the principle of flexible gears, offer higher precision and repeatability, allowing robots to control their position and posture more accurately during movement.
High Load Capacity
The flexible gear principle in harmonic reduction gears allows for higher load capacity, enabling robots to bear larger loads and improving their work capabilities and stability.
High Transmission Efficiency
The transmission efficiency of harmonic reduction gears is generally over 90%, reducing energy loss during transmission. This allows robots to utilize energy more efficiently, enhancing their work efficiency.
High Reliability
Despite their complex structure, harmonic reduction gears offer higher reliability. The flexible gear transmission principle reduces friction and wear, thus extending the service life of robots.
Based on the above comparisons, robots require small size and high precision performance. Harmonic reduction gears can achieve high precision, minimal backlash, high reduction ratios, and small size to the greatest extent, meeting the flexibility demands of small and medium-sized robots.
Therefore, high gear ratios, compact size, and zero backlash make harmonic reduction gears critical components for precision industrial robots. Due to the extensive use of harmonic reduction gears in robot joints, industrial robots are regarded as having extremely high repeatability. Modern industrial robots can achieve repeatability in the micrometer range over thousands of operational cycles.
Compared to ordinary reducers, robots using harmonic reduction gears possess higher precision, load capacity, transmission efficiency, and reliability. Therefore, selecting the appropriate reducer in robot development and application is crucial for improving the performance and technical level of robots.
