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The smoothness of the main bearing of cement mill and its handling
Source: China Bearing Network Time: 2018-06-08
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1. The correct casting and machining of the main bearing bush of the manufacturing equipment mill and the quality of the scraping are the key to ensuring the quality of its manufacture. The detailed manufacturing skills are as follows:
(1). Before casting the bearing bush, the bearing bush should be fully preheated; the moisture of the tile body should be completely transpiration (especially when casting the old tile from the head; the residual cooling water should be kept in the cavity of the bearing bush); to prevent the liquid babbitt during casting. "Fryer" hurts people.
(2). After sufficient warm-up; use electric wire grinding wheel to remove the oxide film of the tile surface (high skill requirements; also need to hang tin on the tile surface); to ensure the tile lining and cast iron tile surface firm bonding; avoid shelling.
(3). After the bearing is cast; after seeing the bearing bush without cracks and blisters; also for the water pressure test; check for the appearance of water leakage; if any; must be welded; until there is no leakage point to stop. Otherwise in use; The cooling water of the bearing bush will leak into the smooth oil of the main bearing of the mill; the smooth oil will be transformed; the normal operation of the bearing bush will be affected.
(4). When using vertical car bearing blanks; it is necessary to strictly control the amount of feed and the speed of the worktable; avoid excessively high cutting heat; make the tile surface blue or even yellow;
(5). After the bearing bush is opened, the oil groove should be in the corresponding hollow shaft journal (this is very important; because the bearing bush and the hollow shaft are one-to-one matching), the oil is applied and the red powder is applied; and the bearing bush is fastened to the hollow shaft. Grinding on the journal; performing the necessary scraping according to the spread of the touch point; until the touch surface of the tile is adjacent to the center line of the tile and the touch point is evenly stopped; the appearance of the tile mouth, bottom touch and diagonal diagonal touch cannot be presented.
(6). Controlling the clearance between the hollow journal and the bearing bush within the skill requirements is the fundamental guarantee for the quality of the bearing scraping. The associated parameters (the contact angle of the bearing bush is usually 700, 02. 2mx6. 5m ball mill hollow shaft journal diameter D is 900mm; the opening angle of the tile is 1200) Substituting into the fraction 120/70 = 7rD2/X; the length of the touch arc can be calculated as X=824.25mm; then X=824. 25mm generation fraction L= ('irD-2X) /4 can calculate the gap arc length L = 294. 375 mm. The bearing pad side gap H is: H = D / 1000 = 0.9 mm; then the formula L / H = L, IH is used. It is possible to calculate the value of the void H at any concentration L:. This empirical formula is very important; it is a reasonable basis for measuring the gap between the hollow journal and the bearing bush. When measuring, it should be noted: measuring at a depth of lOmm The maximum side clearance H; in the gap H; 0. 5mm to measure a point; and the entire gap arc length depth measurement point not less than 5; the axial measurement point is not less than 8; in order to avoid smooth oil in When the mill is working, it flows out from the side of the tile; the gap between the straight sides of the dam is l Omm (the length of the arc) is less than the regular gap value.
(7). In order to make the empty shaft and the tile touch surface store a certain smooth oil; the touch surface should be touched; so that there are 1-2 touch points in 1cm2. However, the number of touch points is too small; the touch strength of the bearing pad cannot be ensured.
(8). 02. 2mx6. 5m ball mill main bearing bush is the active self-aligning spherical tile; in order to make the spherical tile and the tile seat evenly stressed; need to scrape the concave spherical surface of the spherical tile back and the tile seat; and the concave spherical surface in the tile seat Red Dan powder; use the tile back and concave spherical surface to grind the way to investigate the spread of the touch point on the concave spherical surface; until the uniform cloth stops.
(9). When the new equipment mill is just started, the bearing surface does not constitute an oil film; therefore, before the test; the smooth oil should be sprayed on the surface of the two shafts of the mill in advance; in order to prevent the bearing surface from being pulled. The end of the test should be replaced in time. Smooth oil; because the bearing bush and the hollow shaft journal run together, some fine babbitt particles will occur; mixing in smooth oil will cause abrasive wear; so it is necessary to remove it after oil change.
2. Sealing method The traditional main bearing of the mill is sealed with wool felt ring; it is easy to be worn; the seal is unreliable. The theory proves that the dust particles enter the main bearing through the gap between the worn wool felt ring and the hollow shaft; these dusts The particles are the primary cause of abrasive wear and oil passage obstruction of the spherical bearing; therefore, the sealing equipment should be improved. The author used the radial labyrinth sealing method to improve the sealing method of the main bearing. The detailed method is: using the original steel plate One male and one female two sealing steel rings; the male and female sealing steel rings are corresponding to the radial annular labyrinth groove according to the radial labyrinth sealing requirements; and the male and female sealing steel rings are separated from the equipment on the main bearing cover and the hollow shaft of the grinding machine; (Paste butter in the labyrinth before the equipment; to reduce friction; and have a certain sealing effect). This way; the sealing steel ring fixed on the main bearing cap of the mill is not moving; and the sealing steel fixed on the hollow shaft The circle works with the hollow shaft; the sealed labyrinth groove is used to block dust particles and other impurities from entering the main bearing of the mill. The theory indicates; the sealing effect is good; the operating rate of the bearing bush is also large. Progress.
3. Smooth Skills Cement Factory 02. 2mx6. 5m mill main bearing bushings are generally smooth with dynamic pressure. Here is a comment on the smoothing method.
(1). Appropriate smooth oil should be selected and appropriate additives should be added; this can improve the smoothness of the main bearing of the mill. The main bearing of the mill is characterized by large load and large linear velocity; and is subject to shock and oscillation; the dimensions of the bearing bush and the hollow shaft are also Large; further advances in shape, dimensional accuracy, and appearance finish are constrained by conditions such as manufacturing and processing. Thus, the main bearings of the mill generally do not ensure complete liquid sleek; The outstanding gap is smooth (depending on the function and strength of the gully membrane), which can significantly reduce the friction coefficient; reduce the wear of the bearing bush. Therefore, it must be based on the temperature, the linear speed of the hollow shaft journal operation and the load received by the main bearing. Select the smooth oil type. In the south; 02. 2mx6. 5m cement mill main bearing can choose N220 and N320 industrial gear oil in winter and summer. Secondly, because the working temperature of the main bearing of the mill discharge end is higher than the feeding end The load received is also large; so it can be considered that the main bearing at the discharge end uses a smoother oil with a higher viscosity. In the main bearing smooth oil, it should also participate in the stearic acid polar additive to improve the strength of the gap film; The gap film breaks.
(2). According to the normal use period of smooth oil; add or replace smooth oil in a punctual and appropriate amount; and do a good job of storage of smooth oil and waste oil recycling.
(3). Establish and improve the inspection rules for grinding machine workers. The grinding machine should observe the oil temperature, oil quality and oil quantity of the main bearing of the grinding machine; especially when the main bearing temperature is not normal; the inspection frequency should be added; once an abnormality is found, it should be reported in time. In the production theory; there are two situations that are most likely to be numb-grinding and cause a major accident in the burning of tiles: First, because the bolts of the main bearing upper cover fixed scraper loosen, the scraper and the fixed oil ring are dislocated; Smooth oil can not be scraped; and it is drenched on the hollow shaft journal through the oil sump; the bearing bush is short of oil and burned, and the second is because the dust and other impurities block the oil return path of the main bearing base; the fixed oil ring cannot be from the base oil chamber Stir on smooth oil; it will also cause burning of tiles due to lack of oil.
4. Work fault diagnosis and disposal usually the main bearing work problems are the following:
(1). The temperature of the smooth oil is gradually increased; the outer surface of the hollow shaft journal constitutes a streak with babbitt alloy; the deep streaks can reach about 2 mm; and the density is uneven. The reason is that the smoothness of the hollow shaft journal is not good. The tile touch point is subjected to the shear stress effect and causes a large area strain (shear damage). The babbitt particles are pasted on the outer surface of the hollow shaft journal; the hollow shaft is turned to the upper part and meets the cold smooth oil and is coldly disposed; Then the hardness is improved; when it goes down with the hollow shaft; the tile surface is pulled; the strips of unequal distance are present. Together; the hollow shaft with the babbitt particles adhered to the friction after the cycle work; the main bearing The smooth oil temperature gradually rises and the high temperature occurs. At this time, the bearing bush should be pulled out; the tile surface is scraped from the head; the streaks are too deep; the homogenous babbitt alloy should also be repaired.
(2). The side of the bearing bush exhibits a high temperature. This is because the tile seat adjusts the problem; the small surface touch of the tile surface and the hollow shaft journal is combined, and the static load is increased. At this time, the mill cylinder should be jacked up; view the spherical tile back and tile. The touch condition of the seat; if necessary, the tile seat and the tile back should be grounded from the head; make it self-contained. Together, scrape the tile surface from the head; completely scrape off the oxide layer; and polish the hollow shaft journal with oilstone.
(3). When the temperature rises; when there is t, the gloss of the main shaft is dim; and there is a sticky appearance; this is because the tile surface is high temperature and is formed by gluing; at this moment, the bearing should be scraped; sometimes the main shaft is bright; this is because the oil is poor; More impurities; should be changed.
(4). The oil temperature is high; but there is no adhesion of the Babbitt alloy. The reason may be as follows: First, the smooth oil supply is small and the viscosity is low; the oil film cannot be formed, the second is poor oil quality, and the third is the research tile. Reach the standard demand; the gap in the mouth of the mouth. The phoenix æ°– æ°– 嵬å©ç¦æ·™ ┩ ┩ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯ å¯.
5. Conclusion A large part of the cement mill's fault is due to the smooth and poor composition of the main bearing of the mill. Therefore, improving the manufacturing equipment skills of the bearing bush, improving the sealing method of the main bearing and adopting a reasonable smooth method are very important for the normal operation of the mill. Following the development of the cement industry; cement mills are also being carried out to large-scale and active. Therefore, cement companies perform preventive repairs on cement mills; that is, it is necessary to develop a careful pre-repair plan.
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