Mounting Anti-friction Bearings

1
Mounting Anti-friction Bearings

• IMT 161
• Drive Systems
• Chapter 4

2
Load Capacity

• The ability of the bearing to sustain a given
  weight or pressure.
• Factors Type of bearing, number of rolling
  elements, number of rows of rolling elements,
  material used in the bearing.

3
Load Capacity

• The major limitation of anti-friction bearings is
  their lack of fatigue resistance.
• Because the load is concentrated on a fairly
  small contact area, the metal will eventually
  fail.

4
Load Rating

• Load rating is expressed in two ways
• Dynamic load rating refers to the load that the
  bearing can handle during the time required for 1
  million revolutions of the inner ring.
• Basic static load refers to the amount of load
  that the bearing can sustain if the shaft is not
  rotating.

5
Effects of Load and Speed

• The amount of load a bearing can handle is
  directly related to bearing speed.
• More load less speed the bearing can handle.
• Less speed more load the bearing can handle.
• If operating speed is doubled, bearing life is
  cut by 1/2.

6
Fatigue Failure

• Begins as flaking, caused by repeated stress.
• Flaking leads to spalling, where metal begins to
  chip or break away.
• Shock loading puts extra stress on a bearing,
  causing premature failure.

7
Fatigue Failure
8
Environment

• Temperature--can cause deterioration of lube.
  Also, may cause excessive expansion or
  contraction of bearing rings, shaft and housing.
• Contamination--can cause excessive wear of
  rolling elements if it can get into the bearing.
  (Moisture, corrosives or solid contamination.).

9
Mounting Types

• The accuracy of the mounting should equal the
  precision of the bearing.
• Factors of mounts
• 1. Required accuracy.
• 2. Shaft speed.
• 3. Load requirements.
• 4. Bearing life.
• 5. Ease of maintenance.

10
Fixed and Floating Bearings

• Generally, when mounted in pairs on a shaft one
  bearing will be fixed to the shaft and to a mount
  or housing.
• The fixed bearing will carry any thrust load.
• The other bearing will be allowed to float.

11
Fixed and Floating Bearings

• This allows confinement of radial motion while
  allowing axial expansion of the shaft.
• This will prevent overloading the bearings.

12
(No Transcript)
13
Fixed and Floating Bearings
14
Bearing Fits

• Slipping or creeping occurs when the mounting
  ring is too loose on the shaft or if the bearing
  is loose in the housing.
• Causes rapid wear of the shaft and the ring.
• Can also cause the housing to wear and this may
  be very .

15
Mounting Methods

• There are many different ways to mount bearings
  on equipment.
• Generally, mounts will prevent excessive axial
  movement.
• Generally, mounts will allow some adjusting of
  the bearing to be done.

16
Shoulders
17
Lock Nuts
18
Lock Nut and Washer
19
End Plate
Wires keep bolts from backing out
20
End Cap With Shims
Wires keep bolts from backing out
21
End Cap and Shims
Shims allow adjustment of bearing
22
Clamp Plate
23
Tapered Sleeve
24
Tapered Sleeve and Snap Ring
Lock washer
25
Setscrew Lock
Larger bearings will have 2 setscrews.
26
Cotter Pin Lock
27
Cotter Pin Locks
28
Locking Devices
29
The End!!!!