Gear of ball mill video:
The big and small gear of ball mill
are one of the common wearing parts of the edge drive ball mill. The proper material selection and good lubrication have a great impact on the normal operation of the big and small gears.
In order to ensure that the big and small gears have a higher service life and the mill has a higher working performance, the selection of gear materials and lubrication must be appropriate.
1. Gear material of ball mill:
Big gear ring material:
ZG270~500 and ZG310~570 are generally used, but they must be normalized before processing to reduce the hardness to HB170~200.
Big ring gear of ball mill - China
Pinion / small gear material:
35SiMn, 45MnB, 40Cr and other materials are used.
Pinion / small gear of ball mill - China
Pinion / small gear of ball mill - China
The damage of big and small gears in edge drive is mainly due to the wear and bending of the tooth surface. Therefore, gear materials are required to have sufficient strength, high wear resistance and good processability.
2.Gear structure characteristics
The gear transmission of the ball mill is a semi open gear transmission (this article refers to the involute gear and the edge single transmission). The pinion is on the left or right lower part of the big gear and is supported on the transmission seat through the transmission shaft. The installation angle of the gear pair (the included angle between the center line of the big and small gears and the horizontal line) is generally about 20 °. The big gear has two structures, one is integral gear and the other is split gear. The gear teeth are arranged into three types: straight gear, helical gear and herringbone gear. In order to prevent dust and lubricating oil splashing, the gear pair is equipped with a relatively complete protective cover.
The gear drive of ball mill has many disadvantages, such as high transmission power, low speed, heavy load starting, impact load and easy to enter dust and even pulp during operation.
4. Daily maintenance of gear
During maintenance, the big and small gears need special attention. During operation, the operation shall be carried out in strict accordance with the operating procedures. Before starting the whole ball mill, as before starting other equipment, the internal conditions of the ball mill barrel shall be strictly cleaned, the lubrication system shall be checked, and the lubrication system shall be checked to ensure the high and low pressure oil pumps and oil pipelines. The details are as follows.
When starting, these works can ensure the normal operation of the high-pressure oil pump, and this is the time when the ball mill really works. During the inspection of the ball mill gear, pay attention to the above lubrication measures. If everything is normal, closely observe the working condition of the gear. If the shutdown time exceeds 4 hours, pay attention to the slow start and slow drive, and put less pressure on the gear. Only in this way can the load be effectively reduced and the service life of the gear be prolonged.
During daily cleaning of gear oil, the lubrication of big gear and small gear shall be maintained. After Lingli, the large and small gears should have good lubricity based on the amount of alcohol to prevent excessive wear. If the wear surface is too large, the reverse side can be turned to save use. If both sides are worn, replace the gear to fix it.
5.Reasons for wear of big gear
5.1. Influence of gear hardness
The hardness of big gear must be above HB300, and the hardness of small gear tooth surface must be above HRC45.
5.2. Improper selection and maintenance of lubricating oil
Lubricating oil is an important guarantee for the normal operation of the ball mill gear, and it has the function of reducing noise and wear.
5.3. Insufficient sealing of gear end face
After the ball mill has operated for a period of time, the felt on the end face will lose its elasticity due to long-term extrusion, resulting in gaps at the felt. Once the ball mill is in a dusty operating environment, dust and impurities will enter the gaps, affecting the lubrication effect of the gear and causing gear wear.
Parameter of the Gear of ball mill
Big gear ring material：ZG270~500 and ZG310~570 are generally used, but must be normalized before processing to reduce the hardness to HB170~200.
Small pinion gear material： 35SiMn, 45MnB, 40Cr and other materials are used.
6.Methods to reduce wear of big gear tooth surface of ball mill
6.1 Improve machining accuracy.
6.2 Improve the hardness of tooth surface.
6.3 Increase the overlap coefficient.
6.4 Adjust the slip coefficient accurately.
6.5 Improve gear sealing.
6.6 Do a good job of lubrication
6.7 Correct installation and maintenance
Pay attention to:
1) Ensure that the top clearance, runout and contact of big and small gears meet the specified requirements;
2) Ensure the meshing accuracy of big and small gears;
3) During installation, the influence of the working deflection deformation under the load of the ball mill shall also be considered, the elevation difference of the feeding and discharging ends shall be calculated, and the meshing accuracy shall be ensured during operation to avoid eccentric load;
4) Press in method should be used when assembling small gears to prevent premature wear due to annealing of small gears and reduction of tooth surface hardness due to hot installation, which will affect the large gears due to the reduction of meshing accuracy. When the small gears are worn to the limit, they should be replaced in time to avoid impact load due to excessive meshing clearance;
5) When changing the pinion, manual grinding or shot blasting can be carried out to reduce the gear roughness;
6) After the big gear is worn to the limit, it can be repaired and reused according to the wear condition, so as to prolong the service life of the gear and save material costs;
7) Large modification method can be used to repair ordinary gears, and large pressure angle method can be used to repair large modification gears.
8) Regular patrol inspection and daily maintenance are also very important for gear operation, such as regular inspection of the stability of the injection system and the temperature of the gear meshing surface. For large gears, the system can be completely cleaned with organic solvent every one to two years to ensure that the system is smooth and flexible, and the residual dirt on the gear surface can be removed at the right time, thus extending the service life of the large gears.
7. RFQ of ball mill gear:
1. How to deal with the oil leakage on both sides of the big gear of the ball mill?
This usually happens when there is too much oil or the air hole is blocked, so it can be adjusted according to the actual situation.
2. Which lubricating oil is used for ball mill big gear? model?
The daily operation of the ball mill is inseparable from the lubrication of lubricating oil. Good lubricating oil can help reduce the loss and the chance of unexpected shutdown, which can benefit users a lot.
3. The big and small gears are not assembled properly
The engagement between the small gear and the big gear ring of the ball mill is very critical. If it is assembled properly, the service life of the big and small gears of the ball mill can be extended and the vibration can be reduced. When the big gear and small gear are installed, the big gear ring has been fixed with the cylinder. At this time, we need to adjust the position of the small gear. It is required that the small gear is parallel to the axial centerline of the big gear ring, and the clearance between the top gear and the side gear is appropriate. If it is too small, it is easy to undercut, and if it is too large, it is easy to break the teeth.
4. The end cover leaks slurry, and the pinion is worn
The lining plate of the end cover of the ball mill is a cast iron rough workpiece. Under the impact of materials and steel balls of the ball mill for a long time, the bolts that fix the lining plate of the ball mill are often loose, causing the slurry to leak out from the bolt holes of the end cover. In addition, the transmission gear ring cover is not tightly sealed, so the slurry is very easy to be thrown onto the gear ring, causing the big and small gears to wear too fast, shortening the service life, and breaking the teeth when the starting force is large.