How to choose a reduction gearbox?

　　 When getting help from a customer or manufacturer, an engineer is more likely to obtain a transmission that can be installed correctly and meets specifications. After answering and evaluating possible questions:
　What is input speed and horsepower?
　What is the target output speed and output torque of the gearbox? This part is determined by the required reduction ratio.
　What are the characteristics used? How many hours will the gearbox run? Does it need to endure shock and vibration?

　Is the load cantilevered? Is it an internal cantilever load? Keep in mind that helical gears are usually not able to accommodate multiple supports because their shafts are crossed. Therefore, one or more gears are usually suspended. This load will cause the shaft to deflect, and this will make the gear misaligned, but will degrade the contact and life of the teeth. One potential fixation is the cross-shaft on each side of the gear.
　　 Does this machine need a shaft or hollow hole input? Or a shaft or a hollow hole output?
　　How to position the gear drive? For example, if a right-angle worm gearbox is developed, does the machine need to add a worm above or below the gear? Does the axis protrude horizontally or vertically?
Is the environment necessary for corrosion-resistant paints? Or stainless steel housing and bearings?
　　Operation rate: The starting point for most gearbox manufacturers is to define an operating rate. This is based on input type, daily usage time, vibration or jitter related to the application. An application with irregular vibrations (a grinding application) requires a higher operating rate compared to a regular load. Like this, an intermittently running gearbox requires a lower coefficient than the one used 24 hours a day.
　　 Service level: An engineer determines the operating rate, and the next step is to determine the service level. A gear box equipped with an ordinary AC motor drives a stable load. For example, a 20-hour constant-speed transport aircraft may have 2 service levels.
　　 Most of the time, the design engineer equips the gear set with the motor. These configurations get a Roman numeral service class number (I, II or III), which is independent of the gear set operating rate.
　　 Cantilever load: After the designer selects a size, the gearbox manufacturer’s catalog or website will list the maximum cantilever load allowed by the size unit. Recommendation: If the load in the application exceeds the allowable value, increase the size of the gearbox to withstand the cantilever load.
　　 It is best to work with a consultant and use a customized gear design, if all applications require a unique motor-gear box combination. Some combinations are more efficient. In fact, working with the manufacturers to get a prefabricated standardized geared motor ensures that the motor-gearbox combination will work and pass the specifications obtained from calculations and tests conducted by the manufacturer. Evaluate the manufacturer’s performance calculations to determine whether the selected geared motor will cause any problems in the application scenario.
　　Remember that today's customized and standardized gears are not mutually exclusive. Although a fully customized gearbox is not very cheap.

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