Analysis and summary of the causes of vertical roller mill vibration

Analysis and summary of the causes of vertical roller mill vibration

It is common for heavy machinery to vibrate during use, as is the vertical roller mill. The impact of slight vibration on the vertical roller mill is not great, but if the vibration is severe, it will be very troublesome, and in serious cases, it will cause the vertical roller mill to stop production. Then we can't help but ask, why does the vertical roller mill vibrate? Is there any good solution? SBM heavy machine combined with more than 60 years of production research experience on the mill to analyze the reasons for the vibration of the vertical roller mill as follows:

First, the vibration caused by bearing wear

There is a spherical roller bearing on each side of the pinion. After a period of operation or maintenance, it will cause wear of the bearing, resulting in larger bearing clearance or pitting of the roller due to abnormal wear. The vibration becomes larger, which causes the meshing of the small gear and the large ring gear to be in an unstable state, resulting in abnormal vibration.

Therefore, it is necessary to establish equipment maintenance accounts and refueling records during the use process. During the refueling process, it is necessary to ensure that the refueling tools are clean and to prevent the entry of stolen goods. At the same time, when the bearing is running for 12 months, it is necessary to carry out clearance measurement on the bearing, and grasp the relevant data to take preventive measures.

Second, the vibration caused by pinion wear

The general design principle is that the material of the pinion gear is weak and that of the large ring gear, and the number of teeth of the pinion gear is less than that of the large ring gear. Therefore, a common phenomenon is that the surface of the pinion gear has more pitting and stepping than the large ring gear. Therefore, when the vertical roller mill is stopped, it is necessary to regularly check the tooth surface of the small gear and the large ring gear, and pay attention to the dynamics of tooth surface wear at all times.

SBM believes that the wear of small gears and large ring gears is divided into four aspects: First, normal wear, that is, wear during normal use. Second, improper lubrication, mainly due to the unreasonable use of lubricating oil, is important for a device to choose the correct lubricating oil. 3. Lubricating oil deterioration. After selecting a suitable lubricating oil for a piece of equipment, you must also pay attention to observe the changes in lubricating oil. When using for six months or one year (according to the brand and working environment), the oil quality must be tested by a professional company. To see if it can meet the current production needs. Fourth, there are stolen goods. This is an open gear. If the seal is not good or the refueling tools are not clean, it is easy to cause stolen goods to enter, which will cause serious damage to the small gears and large teeth.

When the pinion is severely worn or pitted, it will cause the gap on the tooth side to become larger, and at the same time, a large impact sound will be issued, which will directly lead to accelerated tooth surface wear. The usual solution is to turn the pinion over and use it. In the process of turning over, it is necessary to ensure that the tooth side clearance is in the design requirements. SBM believes that the tooth side clearance is more important than the tooth top clearance.

Third, the vibration of the motor bearing seat

If the company's motor is an open-type motor, the connection between the motor and the reducer is cancelled by nylon, and sometimes the bearing housing at the load end will vibrate.

When the bearing seat vibrates, we need to determine the source of the vibration. Generally, the bearing seat, the input of the reducer and the output of the reducer are measured by a hand-held vibrometer, and the source of the vibration is determined by the data.

The general bearing seat vibration mainly has the following aspects: ⑴, nylon write-off wear. The concentricity error of the coupling between the reducer and the motor is large (generally, the alignment is required to be 0.1mm). ⑶, caused by pinion direction transmission.

Solution:

⑴ Replace nylon for cancellation. Generally, the diameter of nylon cancellation is required to be smaller than the diameter of the coupling by 0.5mm.

⑵Recalibration. At this time, the size of bearing clearance at the input end of the reducer must be clear to ensure the accuracy of the calibration data. At the same time, in the calibration process, try to make the two connecting disks of the coupling rotate at the same time to perform metering (because there will be errors during the processing of the connecting disk, it will affect the accuracy of the calibration data).

(3) If the above treatments are still not resolved, it is necessary to re-align the pinion and the reducer coupling.

Fourth, the equipment fixed parts are not fixed firmly

When the vertical roller mill is running for a certain period of time, the anchor bolts of the transmission equipment motor, reducer, pinion bearing housing and main bearing of the vertical roller mill sometimes become loose. If it is not found and tightened, it will directly cause the equipment to be displaced, thereby Generate vibration. This requires us to pay close attention to the relevant positions during the inspection process, and at the same time, formulate related maintenance plans based on the operating time of the equipment and tighten them regularly.

 

Fifth. Vibration caused by other factors

Worn or worn bush, bearing bush wear or bush burning: The edge drive vertical roller mill bearing bush is temperature measured through both sides of the tile, reflecting that the temperature region is not comprehensive enough, so it sometimes appears. When the bush is damaged or burned, it cannot be found in time. When the bush appears Severe abrasion or tile burning can easily cause the vertical roller mill to run erratically, resulting in erratic gear meshing and vibration.

Precautions: Periodic pumping inspection. The normal inspection cycle is 60 months. Periodically inspect the hollow shaft. When the vertical roller mill is stopped, check for scratches visually, and make data records for each inspection. Recording method: Measurements, photos, etc .; Lubricant testing, by checking the lubricating ingredients in use, and analyzing whether there are emulsifiers and alloy ingredients; ensuring the lubricating oil supply: When the vertical roller mill is not working, we will lower the oil station pressure Turn on the pump and observe whether the amount of oil dripping can meet the requirements, such as cleaning the oil supply pipe and checking the low-pressure pump.

The center elevation of the hollow shaft of the vertical roller mill: The specification of the center elevation of the hollow shaft of the grinding head and the tail must be controlled within 1mm (the tail is lower than the head). Because the foundation of each device is made of concrete, due to geological differences or The foundation structure is different, and sometimes the foundation sinks. Therefore, we often have settlement points on it, so what we have to do is to ensure that the settlement points are clear and effective. If we have found that there are no settlement points, we need to re-measure and establish the settlement. Point, at the same time, the hollow shaft elevation needs to be measured to ensure that it is within the requirements of the specification.

⑶. The center height of the large and small gears changes: Because the small and large gears are driven by the small gears, the positive pressure of the small gears is assured to rise vertically. Therefore, during the operation, ensure that the pressure is evenly distributed on the small gear tooth surface to reduce wear. And a way to vibrate. The general design drawings have requirements for the center elevation of the pinion and the large ring gear. Therefore, when adjusting the height of the pinion during the calibration process, pay attention to the impact on the center elevation to avoid unnecessary damage to the pinion. .

The above is the analysis of the causes of the vibration caused by the vertical roller mill by SBM heavy machine based on its own research experience. The reasons for the vibration of the vertical roller mill may be one or several concurrent, so we must be careful in the process of using Observation and comprehensive diagnosis and analysis of the machine can make a better operation box maintenance plan and ensure the normal operation of the machine.

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