Technical Parameters
| Input power | 9kw~3600kw |
| Output torque | 2.3kN.m~900kN.m |
| Transmission ratio | 1.25~450 |
| Price | 5000~1000000 yuan |
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Gear Reducer Faults, Causes and Solutions
I. Gear Reducer Fault: Abnormal Noise During Operation
Causes:
1. Damaged rolling bearings 2. Severe gear wear
Solutions: 1. Replace rolling bearings 2. Replace gears
II. Gear Reducer Fault: Oil Leakage at Joint Surface or Shaft End
Causes:
1. Oil level too high 2. Bolts on upper and lower joint surfaces not tightened or housing deformation 3. Seal failure at upper and lower joint surfaces 4. Shaft oil seal damage
Solutions: 1. Drain oil to specified oil level height 2. Tighten bolts or grind housing joint surface 3. Replace seal 4. Replace shaft oil seal
III. Gear Reducer Fault: High Housing Temperature
Causes: 1. Lack of lubricating oil 2. Bearing damage 3. Overload operation
Solutions: 1. Add oil to specified level 2. Replace bearings 3. Reduce load
IV. Gear Repair Methods and Applicable Quality Standards
1. The roundness, cylindricity, and roughness of the gear inner hole must meet drawing requirements. If wear is excessive, repair can be done using hole expansion and bushing method.
2. When one side of the gear reducer gear surface experiences wear or fatigue pitting, if structurally permitted, it can be used in pairs after reversing direction.
3. If economically feasible, gears can also be repaired using surfacing welding method, ring inlay method, or tooth inlay method.
4. After keyway wear, repair according to the same method as in regulation 1.3.
5. For assembly of gear reducer gears and shafts, most can be directly pressed in with a press. Heat assembly method can also be used; heating temperature generally should not exceed 150℃.
V. Scope of Application, Structural Overview and Performance Conditions of These Regulations
1. Scope of Application
These regulations apply to the maintenance and inspection of involute cylindrical gear, bevel gear, and circular arc gear reducers.
2. Structural Overview
Gear reducers consist of housing, gears, shafts, and bearings. Structural forms include split type and fully enclosed type.
3. Performance Conditions
High-speed shaft rotation speed not exceeding 3000r/min, operating ambient temperature of -40~+70℃, suitable for forward and reverse operation.
Causes and Solutions for High-Speed Shaft Axial Movement in Gearboxes
1. Damage to Four-Point Angular Contact Bearings
Wear of the rollers and raceways in four-point angular contact bearings increases the clearance between rollers and inner raceways, causing axial movement of the high-speed shaft.
2. Rotation of the Outer Ring in Four-Point Angular Contact Bearings
The outer ring of angular contact bearings is positioned by pins. When pins are too short or broken, the outer ring cannot be axially fixed and rotates, causing relative sliding friction between the bearing outer ring, adjustment shims, and end cover. This results in increased end face wear and larger axial clearance, leading to axial movement of the high-speed shaft.
3. Loosening of the High-Speed Shaft Round Nut
This is the most common cause of high-speed shaft axial movement. Loosening or breakage of the round nut locking screw prevents the nut from being locked. Under axial impact from the four-point angular contact bearing, it loosens toward the motor direction, causing increasing clearance between the two halves of the bearing inner ring. The axial movement of the bearing inner ring often leads to wear of the gear shaft journal, so in this case, the high-speed shaft generally needs to be scrapped and replaced.
4. Improper Installation of the High-Speed Shaft Round Nut
During assembly, the round nut on the high-speed shaft was not installed properly, leaving significant clearance between the round nut and bearing inner ring, preventing the round nut from performing its positioning function.
5. Poor Control of Axial Clearance During High-Speed Shaft Assembly
1. The axial clearance of the high-speed shaft bearing outer ring is too large;
2. The axial clearance of the high-speed shaft bearing inner ring is too large; (mainly reflected in gearboxes of 750 and 850 series that use snap rings to fix bearings)
Causes and Solutions for Abnormal Noise in Gearboxes
1. Noise Caused by Dents and Impacts on Gear Tooth Surfaces
Situation: This problem mainly occurs on the test benches of final assembly plants in complete machine manufacturers. The characteristics of this abnormal noise: stable noise frequency, abnormal noise in one direction only, no abnormal noise when rotating in reverse. The specific location of the abnormal noise can be determined by calculating the relationship between the low-speed shaft rotation speed and the noise frequency.
Cause: Collisions during assembly. Due to loopholes in the company's test quality control, a very small number of gearboxes may experience this problem.
Solution: Based on the analysis results, carefully search for impact damage on the relevant gear tooth surfaces. When searching, wipe the oil from the tooth surfaces clean to avoid affecting tactile sensation. The impact damage mainly exists on the tooth top and both sides of the tooth profile.
2. Abnormal Noise Caused by Excessive Pitch Error of Gears
Situation: This problem also occurs in the final assembly plants of complete machine manufacturers. The characteristics of this abnormal noise: stable noise frequency, abnormal noise when rotating in both directions.
Cause: Abnormal noise caused by excessive variation in adjacent tooth pitch during gear processing. The problem gear can be found through the speed ratio relationship by checking the gear inspection report.
Solution: Except for the removable high-speed shaft, on-site treatment is not possible, and it must be returned to the company for replacement and repair.
3. Abnormal Noise from Friction Interference
Situation: This problem is more likely to occur in maintenance workshops. The gearbox cannot be rotated by hand or is difficult to rotate, and friction sounds occur during testing. The causes in wind farms are generally interference between the oil slinger ring and end cover, accompanied by abnormal heating phenomena in relevant parts.
Solution: Identify the parts causing friction interference, and perform repair processing or tightening treatment on the parts.
Causes and Solutions for Excessive Gearbox Oil Temperature
I. Possible Air Cooler Faults
1. Air Cooler Malfunction
Such as electrical short circuits, open circuits, or motor burnout causing the fan to stop operating.
2. Dust Affecting Air Cooler Heat Dissipation
Large amounts of dust covering the heat dissipation fins will affect the air cooler's heat dissipation, resulting in insufficient lubricating oil cooling.
3. Incorrect Air Cooler Wiring
Incorrect wiring will cause the fan to rotate in reverse, leading to opposite airflow direction and affecting heat dissipation.
II. Reversed Oil Pipes from Lubrication System to Oil Distributor and Cooler
The two outlets of the filter are respectively marked to the gearbox or to the cooler. At lower temperatures, oil flows directly to the oil distributor, while at higher temperatures, it enters the cooler. If the oil pipes are reversed, high-temperature oil will not pass through the cooler for cooling, which will inevitably cause excessive oil temperature. This can be solved by installing the oil pipes according to correct requirements.
III. Pressure Valve or Temperature Control Valve Malfunction in the Lubrication System
When the connection between the filter and gearbox oil pipe is correct, but oil still flows through the pipe from the filter to the oil distributor when the oil temperature exceeds 55°C (judgment method: you can touch the oil pipe; if the temperature is consistent with the distributor's temperature or there is vibration from oil flow, it indicates that oil is flowing through this pipe), it means there is a problem with the filter's temperature control valve.
IV. Relief Valve Issues
As a pressure relief component, the relief valve should only function when the gearbox oil temperature is low and pressure is high. Currently, situations have been found where the relief valve still allows oil flow when oil temperature is high. This reduces the amount of cooled oil, and part of the oil returns directly to the gearbox without cooling, leading to insufficient overall cooling and high oil temperature.
Characteristics of Gear Noise Generation
1. In the frequency spectrum of gear noise, both the gear meshing frequency and its natural frequency are present. The former changes proportionally with the rotational speed of the transmission shaft, while the latter is independent of rotational speed. The meshing frequency is generated by the mandatory continuous impact during gear rotation and is an important component of gear noise. The natural frequency of gears is closely related to their structure.
2. Gear noise that requires maintenance is generally produced after long-term use, based on calculations and practical experience with the overall equipment structure and components such as gears, bearings, shafts, and housing. Therefore, gear noise requiring maintenance is determined by comparison with the noise level when the equipment left the factory. While the phenomenon of increased noise is not difficult to detect, finding the noise source is challenging.
3. Regarding the causes of continuous impact between gears, if there are significant errors in pitch and tooth surface profile, the gears cannot mesh and rotate uniformly. Sometimes they accelerate rapidly, sometimes decelerate rapidly, causing collisions between teeth, and the gear teeth are subjected to large additional dynamic loads. In addition, impacts between teeth can also be caused by other external reasons, such as load variations in the transmission chain, oscillatory rotation of the drive shaft, and resonance with the natural frequencies of other components.
Technical Parameters
| Input power | 9kw~3600kw |
| Output torque | 2.3kN.m~900kN.m |
| Transmission ratio | 1.25~450 |
| Price | 5000~1000000 yuan |
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Gear Reducer Faults, Causes and Solutions
I. Gear Reducer Fault: Abnormal Noise During Operation
Causes:
1. Damaged rolling bearings 2. Severe gear wear
Solutions: 1. Replace rolling bearings 2. Replace gears
II. Gear Reducer Fault: Oil Leakage at Joint Surface or Shaft End
Causes:
1. Oil level too high 2. Bolts on upper and lower joint surfaces not tightened or housing deformation 3. Seal failure at upper and lower joint surfaces 4. Shaft oil seal damage
Solutions: 1. Drain oil to specified oil level height 2. Tighten bolts or grind housing joint surface 3. Replace seal 4. Replace shaft oil seal
III. Gear Reducer Fault: High Housing Temperature
Causes: 1. Lack of lubricating oil 2. Bearing damage 3. Overload operation
Solutions: 1. Add oil to specified level 2. Replace bearings 3. Reduce load
IV. Gear Repair Methods and Applicable Quality Standards
1. The roundness, cylindricity, and roughness of the gear inner hole must meet drawing requirements. If wear is excessive, repair can be done using hole expansion and bushing method.
2. When one side of the gear reducer gear surface experiences wear or fatigue pitting, if structurally permitted, it can be used in pairs after reversing direction.
3. If economically feasible, gears can also be repaired using surfacing welding method, ring inlay method, or tooth inlay method.
4. After keyway wear, repair according to the same method as in regulation 1.3.
5. For assembly of gear reducer gears and shafts, most can be directly pressed in with a press. Heat assembly method can also be used; heating temperature generally should not exceed 150℃.
V. Scope of Application, Structural Overview and Performance Conditions of These Regulations
1. Scope of Application
These regulations apply to the maintenance and inspection of involute cylindrical gear, bevel gear, and circular arc gear reducers.
2. Structural Overview
Gear reducers consist of housing, gears, shafts, and bearings. Structural forms include split type and fully enclosed type.
3. Performance Conditions
High-speed shaft rotation speed not exceeding 3000r/min, operating ambient temperature of -40~+70℃, suitable for forward and reverse operation.
Causes and Solutions for High-Speed Shaft Axial Movement in Gearboxes
1. Damage to Four-Point Angular Contact Bearings
Wear of the rollers and raceways in four-point angular contact bearings increases the clearance between rollers and inner raceways, causing axial movement of the high-speed shaft.
2. Rotation of the Outer Ring in Four-Point Angular Contact Bearings
The outer ring of angular contact bearings is positioned by pins. When pins are too short or broken, the outer ring cannot be axially fixed and rotates, causing relative sliding friction between the bearing outer ring, adjustment shims, and end cover. This results in increased end face wear and larger axial clearance, leading to axial movement of the high-speed shaft.
3. Loosening of the High-Speed Shaft Round Nut
This is the most common cause of high-speed shaft axial movement. Loosening or breakage of the round nut locking screw prevents the nut from being locked. Under axial impact from the four-point angular contact bearing, it loosens toward the motor direction, causing increasing clearance between the two halves of the bearing inner ring. The axial movement of the bearing inner ring often leads to wear of the gear shaft journal, so in this case, the high-speed shaft generally needs to be scrapped and replaced.
4. Improper Installation of the High-Speed Shaft Round Nut
During assembly, the round nut on the high-speed shaft was not installed properly, leaving significant clearance between the round nut and bearing inner ring, preventing the round nut from performing its positioning function.
5. Poor Control of Axial Clearance During High-Speed Shaft Assembly
1. The axial clearance of the high-speed shaft bearing outer ring is too large;
2. The axial clearance of the high-speed shaft bearing inner ring is too large; (mainly reflected in gearboxes of 750 and 850 series that use snap rings to fix bearings)
Causes and Solutions for Abnormal Noise in Gearboxes
1. Noise Caused by Dents and Impacts on Gear Tooth Surfaces
Situation: This problem mainly occurs on the test benches of final assembly plants in complete machine manufacturers. The characteristics of this abnormal noise: stable noise frequency, abnormal noise in one direction only, no abnormal noise when rotating in reverse. The specific location of the abnormal noise can be determined by calculating the relationship between the low-speed shaft rotation speed and the noise frequency.
Cause: Collisions during assembly. Due to loopholes in the company's test quality control, a very small number of gearboxes may experience this problem.
Solution: Based on the analysis results, carefully search for impact damage on the relevant gear tooth surfaces. When searching, wipe the oil from the tooth surfaces clean to avoid affecting tactile sensation. The impact damage mainly exists on the tooth top and both sides of the tooth profile.
2. Abnormal Noise Caused by Excessive Pitch Error of Gears
Situation: This problem also occurs in the final assembly plants of complete machine manufacturers. The characteristics of this abnormal noise: stable noise frequency, abnormal noise when rotating in both directions.
Cause: Abnormal noise caused by excessive variation in adjacent tooth pitch during gear processing. The problem gear can be found through the speed ratio relationship by checking the gear inspection report.
Solution: Except for the removable high-speed shaft, on-site treatment is not possible, and it must be returned to the company for replacement and repair.
3. Abnormal Noise from Friction Interference
Situation: This problem is more likely to occur in maintenance workshops. The gearbox cannot be rotated by hand or is difficult to rotate, and friction sounds occur during testing. The causes in wind farms are generally interference between the oil slinger ring and end cover, accompanied by abnormal heating phenomena in relevant parts.
Solution: Identify the parts causing friction interference, and perform repair processing or tightening treatment on the parts.
Causes and Solutions for Excessive Gearbox Oil Temperature
I. Possible Air Cooler Faults
1. Air Cooler Malfunction
Such as electrical short circuits, open circuits, or motor burnout causing the fan to stop operating.
2. Dust Affecting Air Cooler Heat Dissipation
Large amounts of dust covering the heat dissipation fins will affect the air cooler's heat dissipation, resulting in insufficient lubricating oil cooling.
3. Incorrect Air Cooler Wiring
Incorrect wiring will cause the fan to rotate in reverse, leading to opposite airflow direction and affecting heat dissipation.
II. Reversed Oil Pipes from Lubrication System to Oil Distributor and Cooler
The two outlets of the filter are respectively marked to the gearbox or to the cooler. At lower temperatures, oil flows directly to the oil distributor, while at higher temperatures, it enters the cooler. If the oil pipes are reversed, high-temperature oil will not pass through the cooler for cooling, which will inevitably cause excessive oil temperature. This can be solved by installing the oil pipes according to correct requirements.
III. Pressure Valve or Temperature Control Valve Malfunction in the Lubrication System
When the connection between the filter and gearbox oil pipe is correct, but oil still flows through the pipe from the filter to the oil distributor when the oil temperature exceeds 55°C (judgment method: you can touch the oil pipe; if the temperature is consistent with the distributor's temperature or there is vibration from oil flow, it indicates that oil is flowing through this pipe), it means there is a problem with the filter's temperature control valve.
IV. Relief Valve Issues
As a pressure relief component, the relief valve should only function when the gearbox oil temperature is low and pressure is high. Currently, situations have been found where the relief valve still allows oil flow when oil temperature is high. This reduces the amount of cooled oil, and part of the oil returns directly to the gearbox without cooling, leading to insufficient overall cooling and high oil temperature.
Characteristics of Gear Noise Generation
1. In the frequency spectrum of gear noise, both the gear meshing frequency and its natural frequency are present. The former changes proportionally with the rotational speed of the transmission shaft, while the latter is independent of rotational speed. The meshing frequency is generated by the mandatory continuous impact during gear rotation and is an important component of gear noise. The natural frequency of gears is closely related to their structure.
2. Gear noise that requires maintenance is generally produced after long-term use, based on calculations and practical experience with the overall equipment structure and components such as gears, bearings, shafts, and housing. Therefore, gear noise requiring maintenance is determined by comparison with the noise level when the equipment left the factory. While the phenomenon of increased noise is not difficult to detect, finding the noise source is challenging.
3. Regarding the causes of continuous impact between gears, if there are significant errors in pitch and tooth surface profile, the gears cannot mesh and rotate uniformly. Sometimes they accelerate rapidly, sometimes decelerate rapidly, causing collisions between teeth, and the gear teeth are subjected to large additional dynamic loads. In addition, impacts between teeth can also be caused by other external reasons, such as load variations in the transmission chain, oscillatory rotation of the drive shaft, and resonance with the natural frequencies of other components.
