Rolling mill bearing is a precision mechanical part, its service life is not only related to the quality of the shaft and bearing, but also has a close relationship with its correct installation and maintenance. Therefore, attention should be paid to the technical requirements of bearing installation and maintenance.

First, the installation of rolling mill bearings

1. Preparation before installation:

Before installation, the mating surface of each mating part, including roll neck, bearing box, bearing ring, bearing box gland and locking part, should be carefully inspected to check whether its size, shape and position accuracy and mating tolerance meet the technical requirements of the design. The surface matching with the bearing, the edge and burr of the roll neck, bearing box hole and oil hole must be removed, and the high point of the bulge must be cleaned and coated with roll bearing grease.

2, four row cylindrical roller bearing installation:

Install the inner ring: the inner ring of the four-row cylindrical roller bearing is fitted with the roller neck for interference fit, and the inner ring should be heated to 90-100℃ during installation. Do not exceed 120 ° C to prevent incomplete retraction after cooling of the inner ring. Heating method can be used oil tank heating can also be used induction heating, absolutely prohibited with open flame heating.

The increase of the inner diameter when heating the oil tank is calculated according to the following formula:

△d = 12.5×10-6△t.d

Where: △d-- the increase of inner diameter after heating (mm)

△t-- the difference between oil temperature and room temperature (° C), the room temperature standard is 20 ° C.

d-- inner ring diameter (mm)

When installing double inner rings such as FCD and FCDP, the inner ring must be axially aligned with the inner ring and the end face of the inner ring and the labyrinth ring during the cooling process, and the feeler ruler is used for inspection.

Install the outer ring: the outer ring of the four-row cylindrical roller bearing and the inner hole of the bearing seat are generally loose or transitional. For smaller bearings, the whole composed of the outer ring and the roller and the cage can be gently tapped into the bearing seat with a copper rod. For larger bearings, the outer ring and the outer ring assembly can be lifted and placed vertically down into the bearing box using the outer ring or the lifting hole provided on the cage. For FCDP four-row cylindrical roller bearings with movable ribs, the side stop ring, outer ring assembly and middle stop ring of the same type of bearings should not be exchanged.

The outer ring is marked with Ⅰ, Ⅱ, Ⅲ, Ⅳ

The mark is a sign of the load zone (see Figure 1). For the first time

When installing and using, the direction of rolling load should be aligned

I mark mark, can be cleaned and reinstalled later

The rolling load is sequentially aligned with the remaining marks to

Prolong the service life of bearings.

Figure 1: Outer ring load partition marking diagram

3, thrust (positioning) bearing installation

Thrust (positioning) bearings are not allowed to bear the load in the radial direction, so the inner hole of the bearing seat corresponds to the part where these bearings are assembled, and its diameter must be about 0.5 mm larger than the outer diameter of the bearing. The end face of the inner ring of the thrust bearing must be pressed tightly when installed, and the axial direction should be locked to avoid relative rotation on the roll neck, causing wear and burn on the matching surface of the roll neck.

Second, Maintenance and monitoring of rolling mill bearings

Bearings should be maintained and monitored during use to extend their service life.

1. Keep the lubricating oil path smooth, select the type of lubricant according to the regulations, and fill the lubricant regularly. Ensure that the rolling surface of the roller and the sliding surface of the roller and the flange are maintained with good oil film lubrication.

2. Check the sealing condition of the seals regularly and replace the damaged seals in time. Ensure the sealing performance of the bearing to prevent water and oxide sheet from entering the bearing and prevent the external leakage of bearing lubricant.

3, combined with the actual situation of the enterprise, actively carry out the monitoring of bearing operation.

Noise monitoring: Normal operation should be a smooth buzzing sound, regular monitoring and compared with the normal sound, timely detection of abnormal conditions.

Lubricant monitoring: Normal lubricant should be clear and clean, if the lubricant has become dirty, there will be wear particles or pollutants.

Temperature monitoring: When the temperature rises, the operation will be abnormal.

Establish a record card: record the number of days of bearing online use, excess steel and maintenance monitoring status, etc., to strengthen the management of bearing operating status.

Third, lubrication of rolling mill bearings

Bearing lubrication is the use of oil film to separate the relative moving rolling surface from each other, not due to rough point contact caused by excessive wear and failure. Rolling mill bearings are commonly used as multi-compound lithium grease, which has excellent water resistance, rust resistance, excellent high temperature resistance and good extreme pressure anti-wear performance, and can effectively extend the service life of bearings under humidity, high temperature, high load or certain impact load parts. Grease is divided into several grades according to its fluidity, that is, the degree of penetration. The higher the penetration value, the softer the grease. The "roll bearing grease" produced in China is a multi-component compound lithium grease which is composed of high grade grease, acid proof and synergist, and is suitable for the lubrication of rolling mill bearings.

The filling amount of grease is appropriate to fill one-third and one-half of the space of the bearing and bearing housing. If the grease is added too much, it will worsen the deterioration or chinization of the grease due to the stirring heat. At high speeds, it should only be filled to one-third or less. When the speed is very low, in order to prevent external foreign bodies from entering the bearing, the housing space can be filled. The service life of grease is limited, its lubrication performance is gradually reduced in the process of use, and the wear is gradually increased, so it must be replaced at a certain interval of time. When replacing grease, it should be noted that different grades of grease can not be mixed, if it is necessary to replace different grades of grease, the original grease in the bearing should be completely removed, and then add new grease.

Forth, Storage and custody of rolling mill bearings

Bearings are precision mechanical components, and there are strict requirements for their storage and storage.

1, warehouse temperature: bearings are coated with anti-rust oil before leaving the factory, the temperature is too low or too high will lead to the deterioration of anti-rust oil, the room temperature should be controlled at 0-25℃.

2, warehouse humidity: too high humidity will make the bearing rust, the relative humidity of the warehouse should be maintained at 45%-60%.

3, warehouse environment: bearing is best stored separately, when it must be stored with other items, other items must not be acid, alkali, salt and other chemicals. The bearing should be placed off the ground and away from the heating pipe. .

4, regular inspection: according to the provisions of bearing products rust prevention, regular inspection every 12 months. If rust is found in the oil seal packaging, it should be re-packaged.