Maintenance and maintenance of H3HH7-90 industrial gearboxes (typical heavy-load industrial gearboxes, commonly used in conveying, agitating, and transmission systems) are the core links that extend their service life, avoid sudden failures, and ensure the stable operation of the equipment. It is necessary to carry out core dimensions such as lubrication management, condition monitoring, cleaning protection, and regular maintenance . The specific operations are as follows:
1. Core premise: clarify the basic parameters of the gearbox (must check before maintenance)
Before maintenance, you must first confirm the key technical parameters of the gearbox to avoid operating errors (the parameters are usually marked in the gearbox nameplate or product manual):
Lubricant model: is required Special industrial gear oil recommended by the manufacturer (such as ISO VG 150/220/320 extreme pressure gear oil, the manual shall prevail, and it is strictly forbidden to mix different brands and types of oil products);
Lubricating oil capacity: fill according to the oil level observation window/oil scale to avoid 'less oil' or 'oil spill';
Rated speed and rated load: Overspeed and overload should be avoided in daily operation (it is easy to cause tooth surface wear and excessive oil temperature);
Sealing type: Make sure the input/output shaft seal is 'lip seal' or 'mechanical seal' for subsequent targeted inspections.
(If the oil quality is deteriorated, insufficient oil quantity, abnormal oil level), the following operations must be strictly performed:
1. Lubricant filling and replacement
First refill : After a new gearbox or overhaul, the interior needs to be thoroughly cleaned (rinse kerosene with residual impurities), and add it to the 'middle line' according to the oil mark (the oil level observation window is clearly visible to the oil surface, no more than the upper engraving line or no less than the lower engraving line);
Regular replacement cycle :
First oil change: the new machine runs for 200-300 hours (there are a lot of metal debris during the run-in period, so it needs to be replaced in time to avoid aggravation of wear);
Regular oil change: Change once every 6000-8000 hours (about 8-10 months) under normal operating conditions;
Harsh working conditions (such as high temperature > 40℃, high dust, humidity, frequent start and stop): shorten to 3000-4000 hours (about 4-6 months);
Oil change process :
Stop the machine and wait for the oil temperature to drop to 40-50℃ (hot oil has good fluidity and is prone to discharge impurities, avoiding burns due to excessive oil temperature);
Open the oil drain valve/drain screw plug at the bottom of the gear box to completely empty the old oil (must be connected to the oil barrel to recover to avoid contamination);
Close the oil drain valve, add a small amount of fresh oil to flush the inside (about 10% of the total capacity), and empty it again;
Fill new oil according to the standard. After filling, start the gear box to run for 5-10 minutes without load. After shutdown, check the oil level again (the oil level will drop slightly due to the oil on the gear, and it needs to be added to the standard line).
2. Lubricant status check (1 time per week)
Appearance inspection : Observe the color of the oil (normally light yellow/amber. If it turns dark brown, black or turbid, it means that the oil quality is deteriorated and needs to be replaced immediately);
Impurity inspection : Use a clean glass rod to dip in oil to observe whether there is metal debris or powder (if there is, it may be gear wear or bearing damage, and the machine needs to be disassembled and inspected);
Viscosity check : Use your fingers to rub the oil (it is normal to feel lubricating. If it feels dry, viscous or too thin, it means that the viscosity is abnormal and the appropriate oil needs to be replaced);
Moisture inspection : If the oil is layered or emulsified (milk white), it means that moisture is mixed (may be caused by failure of the seal or humidity in the environment), and the oil needs to be replaced and the seal should be repaired.
3. Daily status monitoring (1 time a day, key working conditions are encrypted)
By 'seeing, listening, touching, and testing', we can determine the operating status of the gearbox and detect early abnormalities in a timely manner:
1. Look at: Operation status and appearance
Oil level observation window: Confirm that the oil level is within the standard range (avoid oil level drop due to oil leakage);
Sealing location: Check the seals of the input shaft, output shaft, end cover, and oil discharge valve (if there is oil trace, it means that the seal is aging or the bolts are loose, and the seal needs to be replaced and the bolts are tightened);
Connection location: Check the connection between the gear box and the motor and the coupling/flange of the load (if the bolt is loose, it will cause the transmission to eccentricity, aggravate the gear impact, and it needs to be tightened regularly).
2. Listen: Running noise
Sharp 'whistling': It may be that the gear meshing gap is too small, the tooth surface is worn or insufficient lubrication;
Dull 'impact sound': It may be that the gear teeth are broken, the coupling centering deviation is too large, or the bearing is damaged;
Periodic 'Abnormal noise': It may be that the bearing raceway is worn or the gear tooth surface is peeled off, and the machine needs to be shut down for inspection.
Normal operation: The gearbox should have only uniform 'buzzing' transmission sound, without abnormal noise;
Anomaly noise:
3. Touch: Surface temperature
Touch the gear box box and bearing end cover with the back of your hand (normal temperature ≤60℃, if it exceeds 70℃ or feels hot, the machine needs to be shut down to check the reason);
Causes of abnormal temperature: insufficient lubrication, deterioration of oil quality, poor gear meshing, bearing damage, and overload load, and need to be checked one by one.
4. Test: Key parameters (1 time per month, using professional tools)
Vibration monitoring: Use a vibration analyzer to detect the vibration value of the gearbox housing (vibration speed ≤6.3 mm/s is normal, if it exceeds 11.2 mm/s, it needs to be shut down for inspection, which may be bearing wear or gear imbalance);
Temperature monitoring: Use an infrared thermometer to measure the temperature of the bearing end cap (normal ≤70℃, if it exceeds 80℃, it is necessary to conduct a key inspection).
4. Regular cleaning and protection (1 time per month)
Dust, oil pollution, and corrosive gases in industrial environments can easily lead to corrosion and poor heat dissipation of the gearbox, so cleaning protection is required:
External cleaning : Use high-pressure air (pressure ≤0.5MPa) to blow away dust and debris on the surface of the gearbox, and then use a rag to dip a neutral detergent (such as soapy water) to wipe the surface oil (avoid strong solvents such as gasoline and alcohol to prevent corrosion of the paint);
Heat dissipation protection : If the gear box has a heat sink, it is necessary to ensure that the heat sink is not blocked (dust accumulation will affect heat dissipation and cause oil temperature to rise), and use a brush to clean the gap between the heat sink if necessary;
Environmental protection :
Humid environment: Install rainproof/moisture-proof cover on the top of the gearbox to prevent rainwater and condensate from seeping in;
Dust environment: Apply dust covers (such as maze-type dust covers) to reduce dust entering the interior;
Corrosive environment: Apply anti-rust paint regularly to the surface of the gearbox (if the paint surface is damaged, it is necessary to apply paint to prevent rust).
5. Regular maintenance (performed by operating time/season)
1. Quarterly maintenance (1 every 3 months)
Tighten all external bolts (including end covers, flanges, oil drain valves, and oil mark bolts to avoid loosening due to vibration);
Check the coupling/pulley: If it is an elastic coupling, check whether the elastic pad is aging or cracked (the aging needs to be replaced to avoid transmission impact); if it is a pulley, check the tension of the belt (it is easy to slip, and too tight can easily lead to excessive bearing force);
Check the breathing valve (if the gear box has a breathing valve): Clean up the dust and impurities in the breathing valve to ensure smooth ventilation (avoid the sealing oil leakage due to excessive internal pressure).
2. Annual overhaul (every 12 months or 10,000 hours of operation)
It is recommended that professionals implement it to thoroughly check the internal status:
Preparation before disassembly: record the gearbox installation position, coupling centering data, and empty the lubricant;
Internal inspection:
Gear: Check whether the tooth surface is worn, pitted, peeled, or broken teeth (use a gauge to measure the meshing clearance. If it exceeds the manual value, the gear needs to be replaced or the clearance needs to be adjusted);
Bearings: Check whether the inner and outer rings, raceways, and balls of the bearing are worn or rusted (the rotating bearings should be free of stagnation or abnormal noise. If there is any damage, the bearings of the same type must be replaced, and grease must be applied when replacing);
Shaft system: Check whether the input shaft and output shaft are bent or worn (use a dial gauge to measure the radial jump of the shaft. If it exceeds 0.05mm, the shaft needs to be straightened or replaced);
Box: Check whether there are impurities or sludge in the inner wall of the box (clean thoroughly with kerosene, apply anti-rust oil after drying);
Replace consumable parts: Regardless of the status, annual overhaul requires replacement of all seals (seal rings, oil seals), gaskets, and bearings exceeding their service life;
Reassembly: Assemble in the reverse order of disassembly to ensure that the gear meshing clearance and bearing clearance meet the requirements of the manual. After assembly, run for 30 minutes without loading, and then load and test run (gradually increase the load to the rated value and observe the operating status).
