When designing shafts and spindles, their static strength, fatigue strength, stiffness, and other special requirements should be ensured. Therefore, the load that can basically determine the static bearing capacity and fatigue strength of the shaft in the working load should be used as the calculation load. In this way, it is necessary to understand the load characteristics that the shaft bears during operation.
When the machine is working, the load acting on the shaft may be a static load (a load that does not change over time) or a load that changes over time. In most cases, the axis is subjected to a load that varies over time.
For loads that act on the shaft for a long time and do not change significantly during loading and unloading, they can be considered as static loads. This type of load includes the self weight of the shaft, centrifugal force during rotation, and the fastening force of the assembled parts on the shaft. If the actual load varies within a range of ± 10% -15% from a certain average value, considering the approximate characteristics of the part calculation, this load can also be regarded as a static load.
The loads acting on the shafts of machines such as belt conveyors with continuous feed, centrifugal pumps with constant flow rate, shearing machines on assembly lines, and crank presses with a certain rough size belong to this category. The machinery and equipment used in the chemical and food industries often encounter continuous mixing, rolling, and other processes, and the load on them is also a static load, but the load changes caused by start-up and overload should be considered.