6.8 Bearings Flashcards
What type of applications would plain bearings be used
Where loads are relatively light and motion is relatively continuous. I.e crankshafts and conrods.
What have replaced plain bearings in most modern day applications
Anti friction bearings with rolling elements
What are bearings used to support
The journals of shafts and axles
Bearings for supporting journals which are designed to accept forces at right angles to the drilling axis are called what
Journal bearings or roller bearings
Bearings for pivot journals which are designed to accept forces in a longitudinal direction are called what
Pivot bearings or axial bearings
What are the two main loads that a bearing has to take
Radial and thrust
What are the 5 main types of anti friction bearings
- Tapered
- Needle
- Ball
- Spherical
- Cylindrical
What are raceways normally made from
Chromium steel or chromium nikel steel
What type of starting resistance do roller bearings have
Low starting resistance and suitable for high rotational speeds
When would roller bearings be used over ball bearings
If the occurring stresses are too severe for ball bearings
How can roller bearings take higher loads than ball bearings
Ball bearings transfer their loads to one particular spot whereas roller bearings take the load along the whole roller
What is the most common used for cylindrical roller bearings
Non locating positions where it is necessary to accommodate for thermal expansion by allowing axial displacement (floating) of the shaft relative to the housing
What type of loads are needle roller bearings suitable for
High radial load capacity only light axial loads
Typical applications are synchromesh mechanisms of automotive gearboxes
What special feature do spherical roller bearings have
A self aligning feature which allows for minor angular displacement between shaft and housing
High radial load carrying capacity
What is special about the tapered roller bearing
Combines the benefits of mot of the other bearings amongst many others
