[Abstract]This article discusses the installation method of the rolling machine bearing according to the technical requirements of bearing installation, and discusses the importance of lubrication to the bearing according to the bearing installation method.
[Keywords] bearing installation maintenance
[1].Installation of rolling mill bearings.The service life of rolling mill bearings is not only related to the quality of the bearings, but also closely related to their installation and use.To this end, attention should be paid to the technical requirements for bearing installation, and the relevant operating procedures should be followed.
1 .pre-installation preparation
(1)Before installation, carefully check the mating surfaces of the roll neck, bearing housing, bearing ring and bearing housing cover plate, etc., to check whether the size, shape and position accuracy and the mating male cover meet the technical requirements of the design.
(2)The edges and burrs of the surface that matches the bearing, the roll neck, the bearing box hole, and the oil hole must be removed, cleaned and coated with lubricating oil.
2 .four-row cylindrical roller bearings are installed
(1)Installation of the labyrinth ring (waterproof sleeve) The coordination between the labyrinth ring and the roll neck is generally a tighter dynamic fit, and a copper rod should be used to tap lightly during installation.The two sides of the labyrinth ring must be parallel and closely fit the shaft shoulder and the inner ring of the bearing.
(2)Install the inner ring of the four-row cylindrical zirconia bearing.The inner ring and the roll neck are fitted with an interference fit.The inner ring should be heated to 90-100 ℃ during installation.Do not exceed 120℃ to prevent the inner ring from being incompletely retracted after cooling.The heating method can be heating by oil tank or induction heating, and heating with open flame is absolutely prohibited.
(3)Install the outer ring four-row cylindrical roller bearing.The outer ring and the inner hole of the bearing seat are generally transitional fit.For smaller bearings, the outer ring, the roller and the cage can be gently tapped in with a copper rod.In the bearing housing.For larger bearings, the outer ring and the outer ring assembly can be hoisted by using the hoisting holes provided on the outer ring or cage, and the outer ring and the outer ring assembly can be installed vertically downwards into the bearing box.For FCDP type four-row cylindrical roller bearings with movable ribs,the side retaining ring, outer ring assembly, and middle retaining ring of the same type of bearings should not be interchanged.
3.the thrust (locating) mounting a bearing thrust bearing four points a corner bearings, double row (single) angle of a corner bearing, two-way thrust tapered and cylindrical roller bearings, recently the company has also developed a braking roller bearings Force bearing.When four-point angular ball bearings and double (single) row angular contact ball bearings are used as thrust bearings, they are not allowed to bear the load in the radial direction.Therefore, the inner hole of the bearing seat corresponds to the part where these bearings are assembled, and its diameter must be larger than the outer diameter of the bearing.The diameter is about 0.5 mm larger.Or the roller diameter is less than the inner diameter of the bearing by about 0.5 mm.
For four-point contact ball bearings,do not interchange the separation rings of the same model during installation to prevent changing the axial clearance when leaving the factory.
For the spacer circle of double-direction thrust tapered roller or double-direction thrust cylindrical roller bearings, the bearings of the same type must not be interchanged to prevent changing the axial clearance when leaving the factory.The end face of the inner ring of the thrust bearing must be pressed tightly and locked in the axial direction.To avoid relative rotation on the roll neck, causing wear and burns on the mating surface of the roll neck.When the brake roller axial force bearing is used, the axial positioning is carried out through two bearing boxes, and the axial clearance is adjusted.When installing the bearing box, make sure that the inner and outer rings of the bearing are in close contact with the inner and outer rings of the main bearing.When axially fixing the bearing boxes on both sides of the frame, attention should be paid to eliminate the axial movement of the bearing boxes in the direction of the shaft end that will occur during the process of introducing the bearing boxes on both sides into the frame.
4.Installation of four-row tapered roller bearings.The fit of the inner ring of the four-row tapered roller bearing and the roll neck is generally with clearance.When installing, first put the bearing into the bearing box, and then put the bearing box into the journal.The outer ring of the four-row tapered roller bearing also adopts a dynamic fit with the bearing box hole, and the outer ring is first installed in the bearing box.Characters are printed on the outer ring, inner ring, and inner and outer spacers when leaving the factory, and must be installed in the bearing box in the order of the characters and symbols during installation.Can not be interchanged arbitrarily to prevent the change of bearing clearance.
After all parts are installed in the bearing box, the inner ring and the inner spacer ring, and the outer ring and the outer spacer ring are axially abutted.Measure the gap width between the end face of the outer ring and the bearing box cover to determine the thickness of the corresponding gasket.
[2].Maintenance and monitoring of rolling mill bearings.The maintenance and monitoring of bearings should be strengthened during use to extend their service life.
1.to keep the road open lubricating oil, according to the provisions of selected types of lubricants, lubricants regularly enough filling.Ensure that the rolling surface of the roller and the sliding surface of the roller and the rib are kept well lubricated with wax.
2.periodic inspection of sealing the sealing member, timely replacement of the damaged seal.Ensure the sealing performance of the bearing to prevent water and iron oxide from entering the bearing and prevent the leakage of bearing lubricant.
3.According to the actual situation of the company, actively carry out the monitoring of the bearing operation status.
Noise monitoring: There should be a steady buzzing sound during normal operation.Regularly monitor and compare with the normal sound to find abnormalities in time.
Lubricant monitoring: The normal lubricant should be clear and clean.If the lubricant has become dirty, there will be worn particles or contaminants.Temperature monitoring: When the temperature rises, the operation will be abnormal.Establish a record card to record the number of days the bearing is used online, the amount of steel passing and the maintenance and monitoring status, etc., to strengthen the management of the bearing’s operating status.
[3].Lubrication of rolling mill bearings
1.the importance of bearing lubrication of lubricating oil film is the use of the rolling surfaces in relative motion apart from each other, not because of rough point contact leads to excessive wear and failure.If users attach great importance to bearing lubrication technology, they can ensure stable performance and rotation accuracy during the predetermined working life.
2.the type of rolling bearing performance and lubrication grease into grease and oil lubrication, grease lubrication advantages lubrication facilities are simple, easy to grease leakage, a certain degree of water, air and other contaminants into the bearing capacity, it is generally Grease lubrication is widely used in this case.Use oil for lubrication under heavy load, high speed, high temperature and other working conditions.
Lubricating grease is composed of base oil, thickening agent and additives.The viscosity of the base oil plays an important role in the lubricating performance of the grease.The composition of the thickener has an important impact on the performance of the grease, especially the temperature characteristics, water resistance, oil separation, etc.The additives are mainly used to enhance the resistance of the grease.Gasification, rust prevention, extreme pressure and other properties.
Grease is classified according to different types of thickeners, and is divided into lithium-based and nano-based.Lithium-based grease is commonly used for rolling mill bearings.Lithium-based grease is characterized by better water resistance, higher dropping point, and can be used on wet and water-contact mechanical parts.Grease is divided into several levels according to its fluidity, namely penetration.The greater the penetration value, the softer the grease.The domestically produced roller bearing grease is a multi-element composite lithium-based grease compounded with high-grade grease and synergist.It is also suitable for the lubrication of rolling mill bearings.
3.the filling amount of grease filling amount of grease to fill one of the bearings and the bearing housing half and a third of the space is appropriate, if added too much fat, the stirring sweep heat, grease deterioration will deteriorate Or Qinhua.It should only be filled to one-third or less at high speeds.When the rotation speed is very low, in order to prevent external alien physics from entering the bearing, the shell space can be filled.
4.replace grease grease service life is limited, decreasing its lubricating properties during use, the wear is gradually increasing, so each must be added a certain time interval replacement.The replenishment cycle of grease is related to the structure, speed, temperature and environment of the bearing, and should be determined according to the specific working conditions of the enterprise.When replacing the grease, you should pay attention to that different grades of grease cannot be mixed.The mixing of different types of thickeners will destroy the structure and consistency of the lubrication.If you must replace the different grades of grease, you should replace the original After the grease is completely removed, add new grease.
[4]Storage and custody of rolling mill bearings.Bearings are a kind of precision mechanical components, which have strict requirements for their storage and custody.
(1)Warehouse temperature: The bearings are coated with anti-rust oil before leaving the factory.Too low or too high temperature will cause the anti-rust oil to deteriorate.The room temperature should be controlled at 0-25 ℃.
(2)Warehouse humidity: Too high humidity will cause bearing corrosion, the relative humidity of the warehouse should be maintained at 45%-60%.
(3)Warehouse environment: The bearings are best stored separately.When they must be stored together with other items, the other items stored together must not be chemicals such as acids, alkalis, and salts.The bearing should be placed away from the ground and away from heating pipes.
(4) Periodic inspection: According to the anti-rust regulations of bearing products,regular inspections are carried out every 10-12 months.If rust is found in the oil seal package, the oil seal package should be re-packed.