What is a planetary gear reducer ? What does "planetary gear reducer" mean?
A planetary gear reducer is an industrial transmission device designed to increase the system's output torque by reducing speed. The main transmission structure of a planetary gear reducer consists of planetary gears, a sun gear, and an external gear ring.
Due to their structure, planetary gearboxes typically have a minimum single-stage reduction of 3 and a maximum of no more than 10. Common reduction ratios are 3, 4, 5, 6, 8, and 10. The number of gearbox stages generally does not exceed 3, but some custom-made gearboxes with large reduction ratios have 4 stages.
Compared to other speed reducers, planetary speed reducers have the characteristics of high rigidity, high precision (single-stage can achieve within 1 minute), high transmission efficiency (single-stage is 97%-98%), high torque/volume ratio, and lifetime maintenance-free operation.
Because of these characteristics, planetary gear reducers are mostly installed on stepper motors and servo motors to reduce speed, increase torque, and match inertia.
The rated input speed of the reducer can reach up to 18,000 rpm (related to the size of the reducer itself; the larger the reducer, the lower the rated input speed). The output torque of industrial-grade planetary reducers generally does not exceed 2,000 Nm, while specially made ultra-high torque planetary reducers can reach over 10,000 Nm. The operating temperature is generally around -25℃ to 100℃, and its operating temperature can be changed by changing the lubricating grease.
Several concepts about planetary gear reducers:
Number of stages: The number of sets of planetary gears. Since one set of planetary gears may not be sufficient for a large transmission ratio, sometimes two or three sets are needed. Increasing the number of planetary gears increases the length of a two- or three-stage speed reducer and reduces its efficiency.
Backlash: With the output end fixed, the input end is rotated clockwise and counterclockwise until the input end produces ±2% of the rated torque. A slight angular displacement occurs at the input end of the reducer; this angular displacement is the backlash. The unit is "minutes," which is one-sixtieth of a degree; it is also sometimes called backlash.
Planetary gear reducers are a versatile industrial product whose performance is comparable to other military-grade gear reducers, yet they are priced like industrial-grade products, making them suitable for a wide range of industrial applications.
This reducer is small in size, lightweight, has a high load-bearing capacity, long service life, smooth operation, and low noise. It features power splitting and unique multi-tooth meshing characteristics. The maximum input power can reach 104kW. It is suitable for use in industries such as hoisting and transportation, engineering machinery, metallurgy, mining, petrochemicals, construction machinery, light industry and textiles, medical equipment, instrumentation, automobiles, shipbuilding, weaponry, and aerospace. The new planetary series includes the WGN fixed-axis transmission reducer, the WN master-slave gear transmission reducer, and the flexible load-sharing low-tooth-difference reducer.
Planetary gear reducers are a new type of gear reducer with wide applicability. The internal gears are made of 20CvMnT carburized, quenched, and ground gears. The entire machine features a small structural size, high output torque, high speed ratio, high efficiency, and reliable performance. This machine is mainly used in the slewing mechanism of tower cranes, and can also be used as an auxiliary component in lifting, excavation, transportation, and construction industries.
