Load Analysis and Calculation Method of Needle Roller Bearings

Needle Roller Bearing

Load analysis and calculation methods for needle roller bearings are key to ensuring that the bearings bear appropriate loads during operation.

The following are some common load analysis and calculation methods:

Radial Load (Fr): Radial load refers to the force perpendicular to the axis acting between the rollers and the track of the bearing. Typically, radial loads are calculated using the following formula:

Fr = P / X

Fr is the radial load, P is the total radial load on the shaft, and X is the dynamic equivalent radial load coefficient of the bearing. The X value can be found from the bearing selection table provided by the manufacturer.

Axial Load (Fa): Axial load refers to the force acting on the bearing parallel to the axis. When calculating axial load, the following formula is usually used:

Fa = 0.5 * P / Y

Fa is the axial load, P is the total radial load on the shaft, and Y is the dynamic equivalent axial load coefficient of the bearing. The Y value can also be found in the bearing selection table.

Combined Load: In some applications, bearings may be subject to both radial and axial loads. In this case, the resultant load can be calculated using the following formula:

Fc = √(Fr² + Fa²)

Fc is the resultant load, Fr and Fa are the radial load and axial load respectively.

Static Load: In addition to dynamic loads, bearings are also required to support static loads, i.e. loads that act when the bearing is not rotating. Static loads are usually smaller than dynamic loads and can be found in the bearing selection table.

Life Calculation: To estimate the life of a bearing, you can use the basic rating life of the bearing (L₁₀ life), which indicates that in a group of identical bearings, 90% of the bearings will continue to work for a specified load. L₁₀ life is usually calculated using the following formula:

L₁₀ = (C / P)^3

L₁₀ is the basic rating life (usually measured in bearing operating hours), C is the basic dynamic load rating of the bearing, and P is the load in the application.

Please note that these calculation methods provide a preliminary estimate of the forces on the bearing. In practical applications, factors such as the working conditions, rotation speed, temperature, lubrication and vibration of the bearing also need to be considered. It is best to consult the bearing manufacturer or use professional bearing selection software for more detailed and accurate load analysis and calculations. This will help ensure that bearing life and performance are reliably guaranteed in practical applications.