Causes and Preventive measures of frequent Burning of main bearing of Ball MillDate: 2019-07-09 Views:
Once the main bearing of ball mill burns, it not only affects the normal production, but also shortens the life of spindle pad. There are many factors leading to the tile burning of the main bearing of the ball mill. This paper shares the cause analysis of the tile burning problem of the ball mill and the corresponding solutions.
Causes of Burning Pad of main bearing of Ball Mill
1. The lubricating oil is unreasonable and the lubricating oil is deteriorating.
In sliding friction, a reasonable bearing oil film can be established to ensure that the two surfaces of the friction pair do not contact directly, and the smaller the friction coefficient is, the longer the working life is. The two main bearings bear the full load of the rotary part of the mill. Therefore, it is necessary to check whether the viscosity index of lubricating oil meets the requirements. The viscosity is proportional to the oil film, the viscosity is too low so that the oil film can not meet the requirements and burn the tile; if the viscosity is too high, its liquidity becomes worse, and the continuous oil film can not be established, resulting in poor lubrication and burning tile.
2. The lubricating oil is deteriorated or mixed with foreign matters
Because the workshop management is not good or the position is not strong, the two ends of the bearing seat are not tightly closed and damaged, the bearing observation hole cover is not covered for a long time, and the like, so that a large amount of dust and other sundries are mixed with the lubricating oil in the main bearing shell, so that the lubricating oil is deteriorated, the friction resistance of the hollow shaft and the bearing bush is increased; in addition, the spherical tile cooling water pipe joint is not tight or the spherical tile water cavity generates a crack, the cooling water is mixed into the lubricating oil, and the oxides and the impurities generated by the chemical reaction in the long-term use of the lubricating oil are added, so that the lubricating oil is deteriorated, The viscosity is reduced and the lubricating property is lost.
3. The oil ring is loose and the lubrication is invalid.
The main bearing is lubricated with thin oil, and the oil ring fixed to the hollow shaft is lubricated with oil. Due to the action of the inertia and the friction force, the steel ball and the material in the mill bin are started to form a steel ball, and the material falls back to impact the cylinder body so as to generate periodic vibration. After the mill is running for a certain period of time, it is affected by its own vibration. The oil circle positioning bolt will be loosened naturally, so that the oil ring is loose. The oil scraper is stuck with the oil ring, resulting in failure of lubrication and dry friction of the main bearing.
4. Improper scraping
Scraping bearing, the original surface contact hard scraped into a little contact, the main idea may be to store a little lubricating oil in the pit for lubrication. In fact, the modern lubrication theory has shown that lubrication is mainly the function of oil film, and the formation of oil film must have wedged clearance. The lubricating oil in pit can not help the formation of oil film, and the contact point can cut through the oil film, which is disadvantageous to lubrication. It can be seen that improper scraping may also be a reason for the main bearing to burn the tile.
5. the swinging of the spherical tile is not flexible
In order to make the tile surface in uniform contact with the journal and uniform load distribution, the spherical tile structure is mostly used in the design of the main bearing, which can make the corresponding multi-dimensional swing with the rotation of the hollow shaft. However, it is not easy to ensure its flexible operation in actual operation, the main reasons are: first, the contact surface is too large, hindering the flexibility of the spherical pendulum; the other is the groove of the concave sphere of the bearing seat, which hinders the flexibility of the spherical tile pendulum. Therefore, due to the inflexible swing of the spherical tile, resulting in uneven force, so that the local burning tile.
6. Hollow shaft deformation
The hollow shaft is actually a thick-wall cylinder, which produces elastic deformation due to the load when working. In addition, because the temperature of the mill increases after a period of operation, the hollow shaft also has thermal deformation. Elastic deformation makes the journal of hollow shaft oval and thermal deformation increases its diameter. The results show that, on the one hand, the contact area between the journal and the bearing changes periodically, that is, the contact stress changes periodically; on the other hand, the gap between the journal and the bearing is reduced, which is disadvantageous to the storage oil and lubrication. The deformation of hollow shaft is one of the most important reasons for the burning of main bearing.
7. Bending deformation of cylinder
when the lining plate and the grinding body are arranged in the mill cylinder body, a large deflection is generated on the cylinder body, so that the hollow shaft at two ends is warped, On-site textual research, at this time, the force is concentrated on an annular strip on the side of the cylinder, and because the contact area is reduced, the pressure is rapidly increased, and the lubricating oil is more difficult to enter the contact area, and finally, the side tile on the side of the cylinder is caused to burn.
8. Other factors
Such as crack, oil leakage, lubricating oil loss, oil level reduction, structure, quality and the like of the spherical tile itself.
Preventive measures for main bearing of ball mill
1. To strengthen lubrication management, operators and managers should strengthen their study, master the relevant knowledge of lubrication, select lubricating oil in strict accordance with the technical requirements of ball mill, and prohibit the improper use and mixing of lubricating oil;
2. The workshop shall strengthen the maintenance management, and do a good job of sealing and plugging of main bearing of ball mill;
3. It is strictly forbidden that the ball mill should be overloaded, especially when it is started, some lubricating oil should be sprinkled on the hollow shaft of the ball mill, or the auxiliary transmission device should be started for a few laps, and then the main transmission device should be started to make the ball mill run.
4. the temperature of ball mill bearing and the change of ball mill current should be checked frequently, and it is found that the bearing temperature is rising or the current is abnormal, so that the bearing should stop immediately, find out the cause and deal with it in time.
5. Pay attention to observe and inspect the cooling water pipe road of the main bearing and dilute gas station to ensure the smooth flow of the water road;
6. when checking or repairing the main bearing, it is necessary to clean the cooling water cavity in time so as not to block the water cavity with mud and sand in the water, resulting in the heat of the main bearing can not be taken away and the tile is heated and burned.
7, pay attention to the sealing of the main bearing to prevent dust entry and lubricating oil leakage. After the dust enters the main bearing, it will not only accelerate the wear of the bearing, but also make the lubricating oil deteriorate and reduce the service life of the lubricating oil.