How to Choose the Fitting Method Between the Coupling's Inner Bore and the Shaft?

The fitting method between the coupling's inner bore and the shaft is one of the key factors ensuring transmission efficiency and stable operation. Choosing the appropriate fitting method requires comprehensive consideration of factors such as shaft diameter, transmitted torque, installation accuracy, and operating conditions.

The fitting methods between the coupling's inner bore and the shaft are generally divided into three types: clearance fit, transition fit, and interference fit. Clearance fits are suitable for applications requiring frequent disassembly or adjustment, such as testing equipment or mechanical systems requiring frequent maintenance. Clearance fits allow for a certain clearance between the shaft and the coupling's inner bore, facilitating installation and disassembly; however, excessive clearance can lead to decreased transmission accuracy or increased vibration.

Transition fits are a type between clearance fits and interference fits, suitable for applications requiring high alignment accuracy. Transition fits ensure a tight connection between the shaft and the coupling's inner bore while providing a certain degree of installation flexibility. This type of fit is commonly used in precision transmission systems, such as machine tools or measuring equipment.

Interference fits are suitable for applications transmitting high torque or high-speed operation. An interference fit generates friction through the interference between the shaft and the inner bore of the coupling, ensuring stability during transmission. This type of fit typically requires heating the coupling or cooling the shaft for installation and is suitable for heavy machinery or high-load equipment.

When selecting a fit type, the material properties of the shaft and coupling must also be considered. For example, when the coefficients of thermal expansion of the shaft and coupling materials differ significantly, an appropriate fit type must be selected to avoid fit failure due to temperature changes. Furthermore, surface treatment processes (such as plating or coating) also affect the fit and need to be adjusted according to the specific circumstances.

Ease of installation and disassembly is also a factor to consider when selecting a fit type. While interference fits provide high transmission stability, installation and disassembly are more difficult and may require specialized tools or equipment. Therefore, a balance must be struck between transmission performance and ease of maintenance when selecting a fit type.