Develop equipment operation and maintenance procedures

Procedures for operation and maintenance of fine, large and rare equipment, major equipment and equipment involving safety shall be formulated.  

 

Equipment operation and maintenance procedures generally include the following contents:  

1) Requirements for site cleaning before operating the equipment.  

2) The tools that must be used to operate the equipment.  

3) Operating procedures and precautions for driving.  

4) Main process parameters of equipment operation.  

5) Content and requirements of equipment state inspection (if necessary).  

6) Lubrication methods and requirements.  

7) Items, contents and frequency of spot inspection and maintenance.  

8) Parking procedures and precautions, and requirements after parking.  

9) Requirements for use and adjustment of safety protective devices.  

10) Causes and troubleshooting methods of common failures.  

11) The specific work of the shift and the record content.

Matters needing attention in the bearing maintenance process

In the process of mechanical equipment maintenance, it is necessary to accurately grasp the direction requirements of mechanical bearings, and only the correct installation can provide guarantee for their work and operation.  Because the external characteristics of some mechanical bearings are not very obvious, they can be installed no matter which direction, so the reverse loading problem often occurs.  Therefore, when assembling bearings, maintenance personnel need to fully understand and accurately grasp the installation and structure requirements of bearings, and fully understand the relevant provisions of the specifications, so as to ensure the accuracy and efficiency of bearing maintenance work.  

The main reasons for bearing damage are:  

1) Material fatigue;  2) Poor lubrication;  3) Pollution;  4) Installation problems;  5) Improper handling.  

In general, 1/3 of the bearing damage is caused by material fatigue;  1/3 is poor lubrication;  The other 1/3 is the pollutant into the bearing or improper installation treatment.  

Common forms and causes of bearing damage

1) Raceway surface and roller surface are covered with dents  

Keep the rack particles and raceway surface wear, grease (agent) discoloration.  Usually this kind of situation is caused by the installation process unclean.  

Keep the installation clean, use new grease, and check whether the seal is in good condition.  

2) wear caused by improper lubrication  

Surface wear is mirror-like, the color is blue or brown.  This situation is caused by insufficient lubrication. It should be the lubrication condition. Redetermine the lubrication period and oil seal.  

3) the dent caused by improper installation  

Both inner and outer ring working surfaces have indentations with spacing equal to the distance between rollers.  The reason is that the installation is not knocked on the correct ring, or in the conical shaft to push too much, or in the static state of overload caused by the load.  

4) dents caused by foreign bodies  

The working surface and the roller surface are full of dents, which may be brought into the foreign body or lubricant foreign body and the surrounding environment during installation.  Clean bearing installation, use clean lubricant and check oil seal.  

5) abrasion of roller end face  

In the roller end face and the guide edge friction, resulting in marks and discoloration.  This condition is caused by excessive axial load sliding or insufficient lubrication.  For this type of damage, a lubricant with higher viscosity can be selected.  

6) roller and raceway abrasion  

At the beginning end of the raceway load area, there is abrasion and local discoloration of the roller, which is caused by the sudden acceleration of the roller into the load area.  

There are two possible approaches;  One is to choose a high viscosity lubricant;  The second is to reduce bearing clearance.  

7) abrasion on the outer surface  

The inner hole of the inner ring and the outer surface of the outer ring have notches and local discoloration, this situation is caused by the relative movement of the ring and the shaft or the bearing box.  The only solution is to increase the fit interference between the ring and the shaft or bearing box to prevent mutual rotation.  Axial braking or clamping does not solve this problem.  

8) Surface pits  

Small and shallow pits on the surface of raceway, rolling body or large section, showing crystalline failure.  This is due to poor lubrication.  For example, lack of oil or viscosity change caused by temperature rise, so that the oil film can not be separated from the contact surface, the surface has instantaneous contact.  

Solution: Improve lubrication.  

9) fretting corrosion  

The phenomenon occurs when there is relative movement between the bearing ring and the shaft or bearing box.  This is due to too loose fit or deformation of the bearing seat.  

10) current corrosion  

Dark brown or grayish black straight streaks or pitting on the surface of rolling or rolling body.  When the current passes through the bearing, the surface of the bearing parts will fuse.  

Method: prevent current flow through the bearing.  

11) Peeling at the symmetric position of the rolling surface  

In the two rings, there is an obvious trace of stress in the radial symmetry position of one ring, and the skin peels off.  This is due to deformation of the bearing box and ellipse compression. The bearing box is remanufactured.  

12) Spalling caused by axial load  

Stress marks are obvious, one side of the ring or a raceway skin of the double-row bearing is peeling off.  

The reason:  

  1. Axial load caused by incorrect installation;  
  2. Pressure transition;  
  3. The non-fixed bearing is stuck or the amount reserved for axial displacement is insufficient.  

13) Peeling caused by imprinting  

The surface of the raceway is peeled off and marked with the same distance as the roller.  This is caused by improper installation of the bearing in a static state of excessive load.  Other microscopic marks may be foreign bodies brought in during installation or in lubricants.  

14) Cracks caused by brutal installation beating  

This crack is an avulsion gap, usually on only one side.  This is due to the brutal knock through the rolling body will be transferred to the end face of the ring resulting in impact.  Do not hit the bearing ring directly.  

15) Cracks caused by excessive extrusion  

The crack passes through the whole section.  This is caused by the interference of the inner ring of the bearing or excessive propulsion on the conical shaft.  

16) Cracks caused by fretting corrosion  

On the inner ring, it is transverse, and on the outer ring, it is circumferential.  It is caused by too loose fit or poor bearing box shape.  

17) peeling caused by fretting corrosion  

The raceway surface of bearing ring is peeled off.  There is corrosion relative to the exfoliated outer surface here.  Fit too loose or bearing box shape is not correct.