JESSICA部落格

1.A brief introduction to planetary gearboxes
‌Planetary gearboxes are a type of mechanical transmission device, also known as planetary reduction gearboxes or gearboxes. Their structural characteristics are that multiple planetary gears rotate around a sun gear to form a special gear mechanism. ‌ This structure not only reduces the transmission speed, but also proportionally increases the torque of the motor, and has the characteristics of smooth transmission and large bearing capacity. Planetary gearboxes are widely used. In addition to being used for micro reduction motors, they are also widely used in the sunshade industry, office automation, smart home, production automation, medical equipment, financial machinery, game consoles and other fields.

2.Classification of planetary gearboxes
1.Classification by power size: Planetary reducers can be divided into high-power planetary reducers and low-power planetary reducers. Although these two types of reducers are only different in power size, they each have different performances and are suitable for different equipment.
2.Classification by the angle of the input shaft and the output shaft: According to the angle of the input shaft and the output shaft, planetary reducers can be divided into right-angle planetary reducers and parallel-axis planetary reducers. The output shaft of the right-angle planetary reducer is 90 degrees perpendicular to the input shaft, while the output shaft of the parallel-axis planetary reducer can be at any angle to the input shaft, and even 360 degrees of dead angle assembly can be achieved.
3.Classification by connection method: According to the connection method, planetary reducers can be divided into round mounting flange planetary reducers and square mounting flange planetary reducers, providing a variety of installation methods to meet different application requirements.
4.Classification by gear arrangement: According to the gear arrangement, planetary reducers can be divided into spur gear planetary reducers and helical gear planetary reducers. Spur gear planetary reducers have a higher cost-effectiveness and are suitable for mechanical equipment running in one direction, at low speed and light load, while helical gear planetary reducers have higher precision and stability, less noise, but are more expensive.
5.Classification by level: The level of planetary reducers can be divided into primary reduction, secondary reduction, and tertiary reduction. Reducers of different levels provide different reduction ratios to meet different application requirements.

3.Selection principles of planetary gearboxes
‌1.Determine the reduction ratio‌: First, the reduction ratio of the planetary reducer needs to be determined based on the rated torque of the motor and the required maximum working torque. The selection of the reduction ratio must ensure that the output torque meets the working requirements, while considering the overload capacity of the motor and the actual working conditions‌.
2.Consider working conditions and environmental factors‌: Including input power, speed ratio, output torque and working environment (such as temperature, load, etc.), these parameters will affect the selection of planetary gear reducers. Factors such as corrosive gases, temperature and humidity in the working environment also need to be considered to ensure the selection of appropriate models and specifications‌.
3.Select the appropriate accuracy level‌: According to the requirements of the application scenario for transmission accuracy, select the appropriate accuracy level, which is generally divided into general accuracy, high accuracy and ultra-precision levels‌.
4.Ensure power requirements‌: Select the rated power of the planetary gear reducer according to the power of the drive motor and the required output power to ensure the normal operation of the equipment‌.
5.Pay attention to reliability‌: Select a planetary gear reducer with high reliability and long life, considering factors such as the quality of the reducer, manufacturing process, and durability of parts‌.
6.Choose the appropriate installation form: Planetary gear reducers have different installation forms, such as flange type, bearing type, flange bearing type, etc. It is necessary to choose the appropriate size and form according to the actual installation space and layout requirements.
7.Easy maintenance: Choose a model that is easy to maintain and repair, considering the sealing performance and the convenience of parts replacement.

4.Reasons affecting the life of planetary gearboxes
1.Load current fluctuation: When the motor line is frequently switched, the load current fluctuates greatly, resulting in significant additional force on the current-carrying wires and reducer windings. The insulation may be damaged under long-term operation, causing short circuits or open circuits, thereby damaging the windings and shortening the service life of the planetary reducer.
2.Rotational changes and rotation processes: These processes will generate additional mechanical forces in the insulation wires of the moving parts, and mechanical connections such as stacking and winding shafts will also generate additional loads. These forces and loads will cause fatigue and weakness in the moving parts and mechanical connections, which will affect the life of the reducer.
3.Thermal overload and temperature fluctuations: Thermal overload will damage the insulation material because the maximum temperature is directly related to the service life of the insulation material. The operating temperature of the reducer cannot exceed the allowable limit temperature of the insulating material. Temperature fluctuations can also affect the service life of the insulating material, such as paint peeling, loosening and other problems.
4.Environmental conditions: Planetary reducers work under different environmental conditions, such as temperature, humidity, dust, etc., which will affect the life of the reducer. For example, a high temperature environment will accelerate the oxidation and deterioration of the lubricating oil, resulting in poor lubrication; a dusty environment will accelerate the wear of gears and bearings.
5.Design and manufacturing quality: The design and manufacturing quality of the planetary gear reducer also have an important impact on its life. An unreasonable design of the reducer may not be able to withstand the predetermined load or working conditions, resulting in early failure. At the same time, factors such as material selection and processing technology in the manufacturing process will also affect the quality and life of the reducer.
6.Installation and maintenance: The installation and maintenance of the planetary gear reducer are also important factors affecting its life. Improper installation may cause the reducer to bear uneven forces, resulting in damage. At the same time, regular maintenance can detect and deal with potential problems in a timely manner and extend the service life of the reducer.

Source:https://plaza.rakuten.co.jp/stepperonline/diary/202409020000/