| Home>Bearing knowledge>Modern large rolling mill oil film bearing DF sealing skills |
Modern large rolling mill oil film bearing DF sealing skills
Source: Bearing network time: 2013-08-30
| /*250*250 was created on 2017/12/25*/ var cpro_id = 'u3171089'; |
The sealing system of the oil film bearing is the key component of the oil film bearing; it has a double effect: on the one hand, it avoids the leakage of lubricating oil in the bearing cavity; the lubricating oil is returned from the tank to the pumping station; ensuring the formation of the oil film in succession, on the other hand, avoiding the outside world. Cooling water, rolling oil (emulsion) and iron filings, dust and other debris enter the bearing cavity; adhere to the normal operation of the bearing. If the seal is ineffective; it will incur foreign matter intrusion; make the lubricating oil pollution aging; lower oil film bearing The number of lifespans will also lead to the leakage of lubricating oil in the cavity; not only does it constitute a lot of oil consumption; and the oil will pour out along the tangential direction of the roll rotation; splashing onto the rolled steel strip and steel sheet; forming pollution; adding annealing Difficult; affect the appearance quality of the steel strip. Therefore; improve the seal layout of the oil film bearing; improve the function and life of the seal is one of the important topics of oil film bearing skills.
1 Layout characteristics The sealing skills and layout of oil film bearings have been carried out for several periods; at present, the third and fourth generation sealing layouts used in the large-scale rolling mills of China's metallurgical companies are also referred to as x-type and DF-type seals.
The X-type seal is attributed to the third-generation oil film bearing seal layout; it is a patent of MORGON. It features a seal section similar to the English letter “xâ€; the seal faces have five lips A, B, c, D, and E. Mouth. D, E is the outer sealing lip; D is the sealing lip; E is the sealing lip; the thickness of the end of the lip is usually about 5mm; touch with the sealing baffle;
The DF seal is optimized for the improvement of the x-type seal layout; it is called the fourth-generation seal. The section of the DF seal is similar to the x-type; the operating principle is basically the same. But it is optimized in three aspects. :
.1) Change the lip and lip of the two outer sealing lips to beveled; the margin of the lip is reduced.
.2) The sealing baffle is changed from the oblique angle to the right angle; when the seal is axially twitched, the two lips are flattened at the same time; the lip will not present a gap.
.3) The mechanism of the seal adopts the principle of negative pressure and pumping; the effect of the seal is significantly enhanced. The DF seal reduces the amount of leakage; the fuel consumption is reduced; the life of the seal is greatly improved; the appearance quality of the steel plate is improved. .
Practice production and use; x-type seal because of large interference; seal wear is severe, the life is short, and the roll has axial turbulence when rotating at high speed; plus the sealing baffle has a certain skew point; D lip or E The lip and the end cap are easy to form when the 霎 is detached; and the x-shaped sealing lip is thick and the followability is poor; the oil leakage is severe and the system is influent. Therefore, the x-type seal has been gradually replaced by the DF-type seal.
2 DF sealing operation principle DF sealing consists of rubber rivets, sealing steel strips, buffers, water seals, sealing baffles, oil seals and type 0 seals.
.1) The sealing steel strip is placed on the waist of the journal seal; the function is to avoid the change of the shape and scale of the centrifugal force of the journal under high-speed rotation.
.2) The aluminum alloy material of the buffer makes its transformation inertia. It has certain corrosion resistance. In addition, the buffer also has axial positioning and hydrophobic action in the rotating state.
.3) The water seal can avoid the flushing of the coolant; make the larger coolant avoid the sealing side of the journal seal; it has a protective effect on the E lip of the DF seal.
.4) Alumina ceramics with good corrosion resistance are sprayed on the touch surface of the sealing baffle and the oil seal; the service life of the sealing baffle is prolonged; the conflict loss is reduced; the inner and outer surfaces of the baffle are processed with a swirling line; When rotating; the spiral is reflowed; it constitutes the pumping action; the oil (or water) entering the outer edge of the oil seal D and the lip of the E is sucked inside the lip; the leakage is reduced; the sealing effect is improved.
.5) The oil seal follows the taper sleeve and the roll synchronously; it has a high-speed relative motion with the sealing baffle; several lip divisions are different; synergistically form a useful seal:
1) Lips A and B hold the roller journal; play a static sealing role. In the meantime, the A lip seals the oil; avoids the leakage of lubricating oil, and seals the lip of the B; avoids the intrusion of external coolant and debris into the bearing.
2) Lip C is the lip of the oil; it blocks a lot of oil splashing from the bearing working surface; and the oil is pulled away from the sealing lip; it acts as an "protective umbrella" for the sealing lip. .
3) Lip D is the sealing lip; E is the sealing lip. They cooperate with the sealing baffle and close to the baffle; adhere to the sealing surface with a certain touch point of view and pressure. When the seal rotates with the roller at high speed; The oil (or water) attached to it is scooped at a certain oblique angle; the fluid flow is subjected to a large inertial force; the flow can hinder the flow of oil (or water) flowing out or leaking through the gap. Together; because the oil (or water) on the lip surface is swept out at a high speed; therefore, a negative pressure occurs at the gap between the lip and the sealing baffle; it helps to seal.
3 Delineation and fabrication to ensure an excellent sealing of the DF seal; optimization of product data selection, layout and mold drawing.
.1) Several aspects of data selection and needs for cooperation:
1) Outstanding oil resistance is the condition for material selection. During the aging process of the medium; the data should ensure that the volume change, the strength change and the elongation change are better.
2) The recovery and follow-up requirements of the lip parts are high; the rubber compound should have outstanding elasticity. During the experiment; the compression value in the air and the medium is small.
3) The standard scale of the product is large, the section is disordered, and there are many metal inserts; when vulcanization molding; it is necessary to think about the scorch period and fluidity of the rubber; reduce the scrap rate; improve the appearance quality and overall quality of the product.
4) The product runs at high speed for a long time; the wear of the two outer lip parts is severe; the wear resistance of the rubber compound can extend the product life.
.2) Product layout depiction 1) DF sealing operation; D, E lip and sealing baffle ceramic surface constitute a hydrodynamic oil film. The thickness of the oil film is essential; thin will cause dry conflict; If it is thick, it is easy to form a leak. The interference between the D and E lips and the ceramic surface of the sealing baffle and the viewpoint directly affect the thickness of the oil film. The product description should fully consider these elements.
2) When the layout is drawn; the dimensions of the sealing groove, the interference of each lip and the rationality of the viewpoint, the matching parts, the spring, the scale of the steel strip and the optimization of the overall layout of the product should also be considered.
.3) Mold depicting DF sealing products with large standard, wide section and multiple lips and metal inserts; mold cavity messy; rubber compounding is difficult to mold during vulcanization molding; easy to attack delamination and internal defects, vulcanization When the mold is thin; the thin lips D and E of the product are easy to tear. In addition, the product is also prone to stagnation, extraction, lack of glue, etc. The mold description should summarize these elements for repeated optimization to ensure the overall quality of the product.
4 Analysis of localized economy DF seals are attributed to consumables; many spare parts are required every year; while oil film bearing seals of large-scale rolling mills in China rely on imports for a long time; there are long-term spare parts purchase period, inventory costs and high-grade defects in product prices. The localization operation has practical economic meaning. Take Baosteel 1580 hot rolling as an example; the annual consumption cost is 120-150 pieces; the original DF seal and water seal each set of imported parts has a basic price of about 10,000 yuan; about 5,000 yuan after localization; Spare parts cost can be saved (10000 5000) × (120 ~ 150) = (600000 ~ 750,000) yuan; significant economic benefits. Further implementation to Baosteel's entire plant; in addition to cold and hot-rolled DF sealing spare parts; Mitsubishi x-type seals need to be modified; handle the serious problems of x-type seal leakage; after localization; not only spare parts cost can be greatly reduced; but also can reduce inventory; and get high-quality on-site service. Progress; many companies are now able to produce products that are equal in quality and lifespan to imported parts; during the Guangzhou Machine Tool Research Institute Sealing Office Has successfully completed the localization research and development of DF seals in Baosteel l420 cold rolling, WISCO, Zhugang and other metallurgical companies; this has invented an outstanding environment for the localization of DF seals in China.
Recommend to friends comments close window
| Bearing related knowledge |
| SKF magnetic bearing features and system content TIMKEN bearing: super-precision progressive function rolling mill bearing smooth TIMKEN imported bearing seal type imported bearing smooth solution plan |
This article links to http://
Please indicate China Bearing Network http://
Previous:Preparation of bearing routine viewing Next edit: How to disassemble the bearing of the vibrating screen
Square Shower Drain,Shower Grates Drain,Square Gold Shower Floor Drain,Square Gold Floor Drain
Kaiping City Jinqiang Hardware Products Co.,Ltd , https://www.kimpowerdrain.com