Roller Bearings Flashcards
Roller bearings
moderate to heavy loads, and handle high impact or shock loads. Sensitive to misalignments. All have line contact
4 categories of roller bearings
Cylindrical, needle, spherical, and tapered
Cylindrical
Have the highest combined radial load and speed
Cylindrical thrust loads
Limited by the amount of heat generated and dissipated
Cylindrical radial speed load
Can be limited by roller guidance, type of cage, type of lub, shaft installation, and housing accuracy.
Fixed bearing
Fixed or secured pivot point at one end of the shaft
Floating bearing
Ability to allow the axial forces to pass through the bearing. Allows thermal expansion
Fixed and floating bearings allow
Allows shaft to rotate freely with minimal radial and axial movement
Needle roller
Carry heavy radial loads in a minimal amount of radial space. Permits the use of larger, stiffer shafts and provides a low friction rolling bearing. 6-1 ratio (length to diameter). If it breaks the rollers fall out. Inner race is always the shaft
Types of needle bearings
Cage separated and full complement style
Cage separated
Have a bearing retainer or element separator as part of the assembly. Accommodate higher speeds and more precision rolling
Full complement style/drawn cup
Needle roller elements are positioned in the outer ring so that each needle is touching
Cam type and load following
Symmetrical and elliptical motions. Has an inner and outer race with a plain or rolling element type bearing between the races
Spherical roller bearings
2 rows of rollers. Spherical outer race. High radial and thrust. Answer to misalignments of .5 to 2 degrees. Needs at least a 4-1 radial to thrust load
Tapered roller bearing
Answer for thrust loading. High radial and thrust. Has an inner ring or cone. An outer ring or cup (always fits over the cone). Shallow angles for radial loads and steeper angles for thrust loads
