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Mounting and Dismounting
 
  Bearing Mounting
Remove all dirt, spurs, metal shavings, etc., from the shaft, housing, related parts and mounting fixtures before mounting the bearing. Check the dimension precision, shape precision, and roughness of the mounting section and make sure they are within tolerance. Leave the bearing in its packaging until you are ready to mount it. In the case of oil lubrication, or even when using grease lubrication, if there is danger of destroying effectiveness of the lubricant by mixing with rust preventatives, remove the rust preventative with detergent oil prior to mounting.  
If you plan to apply grease after cleaning the bearing, you should dry the bearing somewhat before applying grease. If the bearing is to be inserted on the shaft or in the housing, you must apply equal pressure to the entire circumference of the bearing rings (inner and outer) while inserting. Inserting while applying force to just one part will cause the ring to become cocked to one side. If you apply force to the ring that is not to be inserted, load is applied via the rolling elements. This could dent the raceway surface, and should absolutely be avoided. Inserting bearing rings by striking directly with a hammer could crack or break the ring, as well as dent it.
 
Fig. 16.1 Inner Ring Press Fitting
Fig. 16.2 Inner/Outer Ring Simultaneous Press Fitting
Mounting cylindrical bore bearings
As shown in Fig. 16.1, bearings with comparatively low interference are press or hammered into place while applying an equal load to the entire circumference of the bearing by positioning the guide on the edge of the bearing ring to be fit. If mounting the inner and outer rings simultaneously, press fit evenly using a metal block as shown in Fig. 16.2. In either case, be careful the bearing does not become misaligned when you begin mounting. In some cases a guide is used to prevent misalignment.
 
 
 
 
  Dismounting
Fig. 16.6 Measuring Internal Clearance of Self- Aligning Roller Bearings
radial internal clearance of self-aligning roller bearings, let the roller settle into their correct positions and insert a thickness gauge in between the rollers and outer ring where there is no load (Fig. 16.6). At this time, it is important to measure with the rollers still. You can also obtain the proper interference by measuring the amount of drive in the axial direction instead of the amount of radial internal clearance reduction.  
 
Mounting outer rings
If the outer ring is interference-fit into the housing and the interference is large, depending upon the dimensions and shape of the housing, the housing can be heated to accommodate the outer ring, but cold fitting is generally used. With this method, the outer ring is shrunk using a coolant such as dry ice. With cold fitting, however, moisture in the atmosphere tends to condense on the bearing surface, thus necessitating suitable measures for preventing rust and frostbite.
 
 
Post-Installation Running Test
After mounting, the bearings must be checked to make sure they are properly installed. First, turn the shaft or housing with your hand to make sure there is no looseness, the torque isn't too great, or anything else out of the ordinary. If you don't notice anything unusual, run the equipment at low speed without a load. Gradually increase speed and load while checking rotation. If you notice any unusual noise, vibration or temperature increase, stop operation and check out the problem. If necessary, remove and inspect the bearing. You can check the sound volume and the tone of the turning bearing by placing a stethoscope on the housing (see Table 11.2). If there is a lot of vibration, it is possible to infer the source of the problem by measuring amplitude and frequency. Bearing temperature rises along with rotation time, and then stabilizes after a certain period of time elapses. If temperature rises sharply and does not stabilize no matter how much time elapses, you must stop operation and investigate the cause of the problem. Possible causes include too much lubricant, too much seal interference, insufficient clearance, and too much pressure. It is best to measure bearing temperature by touching the measurement probe to the outer ring, but temperature is sometimes measured from the housing surface, or if there is no problem with doing so, by feeling the housing with the hand.
 
Bearing Removal
Bearings are removed for routine inspection and parts replacement. The shaft and housing are usually always reused, and in many cases the bearing itself can be reused. It is therefore important to be careful not to damage the bearing when removing. In order to do so, a structural design that facilitates removal and the use of proper tools are required. When removing a bearing ring mounted with interference, withdrawal load must be placed on that ring only. Never attempt to remove a bearing ring via the rolling elements.
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  Technical Support  
 
1. Bearing History
2. Types of Bearings
3. Types of loads
4. FITS
5. Clearance
6. Bearing Tolerance
7. Lubrication
8. Bearing Storage
9. Mounting and Dismounting
10. Bearing Failures
11. Prefix and Suffix Interchange
11. Allowable Speed
   
 
 
 
 
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