How to determine if the fit between the output shaft of BWD cycloidal reducer and the inner hole of the coupling is loose

1. Observe the operating status and abnormal phenomena

Abnormal vibration and noise: During equipment operation, if significant vibration is observed in the coupling area, or periodic impact or noise is heard, this is usually a direct manifestation of excessive clearance and relative motion.

Abnormal temperature rise: Coupled with looseness, it can lead to increased friction. If the temperature of the coupling and the output shaft bearing of the gearbox rises abnormally (for example, the temperature rise of the rolling bearing exceeds 50 ℃ or the maximum temperature exceeds 80 ℃) when touched or measured, it is highly suspected that it is caused by a fitting problem or poor lubrication.

Visible relative displacement: During equipment start stop or load changes, carefully observe the connection between the coupling and the shaft to see if there is any visible relative rotation or axial movement.

2. Shutdown for manual inspection

Turning inspection: After cutting off the power and stopping the machine, try manually turning the coupling. If there is a noticeable clearance or a significant gap during forward and reverse rotation (i.e. the shaft only rotates after a certain angle), it indicates that the fit has become loose.

Touch and visual inspection: Check the inner hole of the coupling and the surface of the gearbox output shaft. If obvious signs of wear steps, burrs, scratches, or metal extrusion deformation are found, it can be confirmed that there is looseness and wear.

3. Use tools for precise measurement

This is the most accurate method of judgment, usually performed during maintenance:

Measure with a feeler gauge: Try measuring with a feeler gauge at the fitting gap between the coupling and the shaft. If a feeler gauge can be inserted, it directly proves that the fit has loosened.

Dial gauge measurement: Fix the magnetic gauge base on the reducer base, and press the dial gauge probe against the outer circle of the coupling. Manually rotate the coupling and observe the jumping reading on the dial gauge. If the radial runout value significantly exceeds the allowable range of the equipment (for example, general industrial equipment usually requires a radial deviation of ≤ 0.05mm), it indicates that the fit clearance is too large or the shaft is worn.

Dimensional measurement: After disassembly, use a micrometer and an inner diameter dial gauge to accurately measure the diameter of the output shaft and the diameter of the coupling inner hole, calculate the actual interference or clearance value of the two, and compare it with the required fitting tolerance on the design drawing.