CPM Bearings, Seals, and Shaft Couplings 1 — Questions and Answers
Question 1: What type of rolling element bearing is best suited to handle both high radial loads and moderate axial (thrust) loads simultaneously?
- Deep groove ball bearing
- Tapered roller bearing (Correct answer)
- Needle roller bearing
- Thrust ball bearing
Correct answer: Tapered roller bearing
Tapered roller bearings have angled rolling elements that redirect forces so the bearing supports both radial and axial loads simultaneously.
Question 2: When pressing a bearing onto a shaft, force should be applied to which component to avoid damaging the rolling elements?
- The outer ring only
- Both the inner and outer rings equally
- The inner ring only (Correct answer)
- The cage assembly
Correct answer: The inner ring only
Force applied to the inner ring transfers directly to the shaft interface; applying it elsewhere passes load through the rolling elements and damages them.
Question 3: What does a high-pitched squealing or screeching sound from a bearing most commonly indicate?
- Bearing overload from excessive radial force
- Inadequate lubrication causing metal-to-metal contact (Correct answer)
- Excessive internal bearing clearance
- Incorrect bearing type for the application
Correct answer: Inadequate lubrication causing metal-to-metal contact
High-pitched squealing is the classic audible sign of insufficient lubrication, where friction between rolling elements and races generates the noise.
Question 4: The internal clearance of a bearing refers to:
- The gap between the cage and rolling elements
- The total radial movement possible between the inner and outer rings when unloaded (Correct answer)
- The axial distance between two bearing rows
- The tolerance on the bearing bore diameter
Correct answer: The total radial movement possible between the inner and outer rings when unloaded
Internal clearance (radial play) is the total free radial movement between inner and outer rings before load is applied, and it affects heat generation and load distribution.
Question 5: Which bearing type is specifically designed to automatically compensate for shaft misalignment of several degrees?
- Cylindrical roller bearing
- Angular contact ball bearing
- Self-aligning ball bearing (Correct answer)
- Thrust needle bearing
Correct answer: Self-aligning ball bearing
Self-aligning ball bearings have a spherical outer raceway that allows the inner ring and balls to tilt, accommodating misalignment without binding.
Question 6: When using an induction heater to mount a bearing on a shaft, what is the generally recommended maximum heating temperature?
- 80°C (176°F)
- 110°C (230°F) (Correct answer)
- 150°C (302°F)
- 200°C (392°F)
Correct answer: 110°C (230°F)
Heating above 110°C (230°F) risks altering the bearing's metallurgical properties and reducing hardness; the safe range for induction heating is 80–110°C.
Question 7: Spalling on a bearing race is characterized by:
- Surface pitting and flaking of metal from the raceway (Correct answer)
- Discoloration of the raceway from excessive heat
- Corrosion streaks caused by moisture contamination
- Deformation of the cage pockets from impact loading
Correct answer: Surface pitting and flaking of metal from the raceway
Spalling is a fatigue failure mode where repeated rolling contact stresses cause metal to fracture and flake away from the raceway surface, creating pits and craters.
CPM Bearings, Seals, and Shaft Couplings 1
What type of rolling element bearing is best suited to handle both high radial loads and moderate axial (thrust) loads simultaneously?