How long will it take for the lubricating grease of the gearbox to fail and damage the bearings

1、 Bearing damage cycle under different working conditions

Heavy load/impact/high-speed working conditions: After complete failure of the lubricating grease, the bearing will experience dry friction, excessive temperature rise, rapid occurrence of raceway scratches, rolling element peeling, and in severe cases, direct sintering and locking within a few hours to 72 hours. In such scenarios, the oil film completely ruptures, and the wear rate of direct metal contact is extremely fast, causing irreversible damage in a short period of time.

Under normal rated load conditions: After the failure of the lubricating grease, the bearing will gradually produce abnormal noise, increase vibration, and continuously exceed the temperature limit within 1-4 weeks. Subsequently, the clearance will quickly exceed the limit, and eventually fatigue pitting corrosion or cage fracture will occur, completely losing its working ability.

Light load/intermittent operating conditions: When the daily operating time of the equipment is less than 8 hours and the load is below 60% of the rated value, the bearing can still rely on boundary lubrication to maintain for a period of time after the lubricating grease fails. Complete damage may be delayed for 1-3 months, but wear continues to accumulate during this period, and accuracy will quickly lose.

2、 Key factors affecting the speed of damage

Load intensity: For reducers that operate beyond their rated torque for a long time, the speed of bearing damage is 3-5 times faster than under light load conditions; The impact load will directly tear the remaining oil film, greatly shortening the damage cycle.

Operating environment: In scenarios with high dust, high humidity, and high temperature (ambient temperature>60 ℃), impurities will enter the bearings and act as abrasives, increasing the wear rate by 2-4 times and significantly advancing the time of bearing damage.

Bearing types and specifications: Small sized deep groove ball bearings and tapered roller bearings are more sensitive to lubrication failure, with a damage rate about 40% faster than large-sized cylindrical roller bearings.

3、 Key warning nodes

After the failure of the lubricating grease, the bearing will experience abnormal temperature rise (exceeding 80 ℃) within 24 hours, followed by continuous sharp abnormal noise and vibration amplitude exceeding 7.1mm/s within 3 days. At this time, the machine must be stopped immediately to replenish the grease or replace the lubricating grease, otherwise irreversible damage will occur in a very short period of time.