How to judge whether the YTC902-220-11KW shaft-mounted gear reducer needs maintenance

To determine whether the YTC902-220-11KW shaft-mounted gear reducer needs maintenance, it is necessary to combine appearance inspection, dimensional measurement, operating status observation and safety and economic evaluation. Here’s how:

1. Appearance inspection (stop state)

‌Tooth surface wear‌:

‌Uniform wear‌: The tooth surface loses its luster and presents a uniform 'frosted feel', and the edges of the tooth top and tooth root appear rounded. The tooth thickness wear of hard tooth surface gears exceeds 15% of the original tooth thickness, and the tooth thickness wear of soft tooth surface gears exceeds 20%.

‌Local wear‌: 'step-like' wear occurs locally on the tooth top, tooth root or tooth surface, resulting in a reduction of more than 50% in the meshing contact area.

‌Pitting corrosion‌: Dense pits (diameter >0.5mm) appear on the tooth surface, and the pitting area exceeds 30% of the total tooth surface area.

‌Gluing/scratching‌: Strip or block-shaped damage appears on the tooth surface along the sliding direction, and in severe cases, the metal falls off.

‌Tooth root wear‌: Local wear occurs at the transition fillet of the tooth root, which may be accompanied by micro cracks.

2. Dimensional measurement (quantifying the degree of wear)

‌Tooth thickness measurement‌: Use a tooth thickness caliper to measure the chordal tooth thickness at the gear graduation circle, and compare it with the original data. If the actual tooth thickness decreases by more than 10% compared to the original value, be vigilant.

‌Measurement of common normal length‌: Use a common normal micrometer to measure the common normal length of the gear and calculate the wear amount. The reduction of the common normal length ≈ tooth thickness wear × 1.414.

Meshing backlash measurement: Use a feeler gauge or dial indicator to measure the meshing backlash. If the backlash exceeds 50% of the design value, it means that tooth surface wear has caused abnormal clearance.

3. Observation of running status (power-on status)

‌Temperature Abnormality‌: When the gearbox temperature is more than 10°C higher than the normal operating temperature and there is no other heat source, it may be related to wear.

‌Load Fluctuation‌: The output torque fluctuates, the speed suddenly increases and decreases, and is even accompanied by a slight 'stuck feeling'.

‌Abnormal noise and vibration‌: Periodic abnormal noise occurs during operation (such as 'clicking' and 'clicking' sounds), and the vibration value exceeds the standard (radial vibration speed>11.2mm/s).

4. Safety and Economic Judgment

‌Safety risk‌: If the gear is used in key equipment (such as hoisting machinery, main drive of the production line), even if the wear has not reached the limit, there is a risk of tooth breakage (such as small cracks have been found), and it needs to be replaced in advance.

Maintenance economy: If the gear repair cost is close to that of a new gear (for example, a heavily worn gear needs to be reprocessed after surfacing and the cost reaches 80% of a new one), or the service life after repair is less than 50% of a new one, priority is given to replacing the new gear.

5. Comprehensive judgment

If obvious wear marks, pitting corrosion, tooth thickness reduction is observed on the tooth surface, or abnormal noise, increased vibration, or out-of-tolerance meshing clearance occurs during operation, it can be determined that the gear is worn and needs to be repaired or replaced.