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47 Cards in this Set
- Front
- Back
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What are the simplest and least expensive of bearings? |
Plain bearings, aka bushings |
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What keeps the mating surfaces apart when using plain bearings? |
Thin layer of oil |
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What are some advantages to plain bearings vs roller bearings? |
Require less space Quieter Cost less More rigid |
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What is a disadvantage of using plain bearings? |
Create more friction and require constant lubrication |
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What type of bearing supports rotating shafts? |
Radial |
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What type of bearing supports axial loads? |
Thrust |
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What are guide or slipper bearings for? |
Guide moving parts in a straight line |
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The part of a shaft that rides in a plain bearing is called what? |
Journal |
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Plain bearings for rotating shafts are called what? |
Journal bearings |
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What are journal bearings and what are their 2 main functions? |
Plain bearings for rotating shafts Hold the journal in it’s required location Support the radial load |
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What is the limitation of solid plain bearings? |
Low speeds and loads |
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What type of loads are most solid plain bearings meant for? |
Radial |
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To accommodate axial loads what must be added to a plain bearing? |
Flange or thrust washer |
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What sizes are commercial plain bearings available? |
1/4 to 5” |
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What do plain bearings often have to aid in lubrication? |
Inner grooves (circular, spiral, or straight) |
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What are the most common materials for plain bearings? |
Bronze Sintered bronze (Oilite) Cast iron Plastic |
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What material is the best choice for medium speeds and loads? |
Bronze |
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What are some characteristics of bronze that make it a good material for bushings? |
Strong, resists galling on steel journal, easy to machine |
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What is sintered bronze (oilite) and what is it useful for? |
Bronze bushings that are porous to soak up lubricant Can be used in areas where it’s difficult to get lubrication to |
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Is sintered bronze good for high temperature applications? Why? |
No, oil evaporates |
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What type of speeds and loads is cast iron good for? |
Low speeds -130sfm Light loads - 150 lb per sq in |
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What do cast iron bearings need a lot of? |
Lubrication |
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Why are plastics becoming more common as a bearing material? |
Corrosion resistant Easy to machine/mould Require little lubrication |
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What is nylon good for? |
Light loads (toys) |
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What are advantages/disadvantages of Teflon ? |
Very slippery Needs no lubrication Expensive Low loads |
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What does rubber allow for as a bearing material? |
Exposure to water Helps dampen vibration Compensate small misalignment |
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What are two advantages of split plain bearings? |
They can be replaced without having to remove the entire shaft They can adjust for size by adding shims between the bearing seat and cap |
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What keeps split bearings from shifting in the housing? |
Locking tap or Dowel |
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What are the 2 broad categories of split bearings? |
Thick wall Thin wall (thin shell) |
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What are thick wall bearings made of? |
Solid bronze or with a thin layer of Babbitt |
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What materials are used in thin wall split bearings? |
Babbit Layer of copper Steel backing |
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What’s required of the housing bore of thin wall split bearings? Why? |
Rigid and precise Because the bearing relies on the bore for support |
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Where would you find thick wall split bearings? |
Old cars, gear boxes, heavy machinery |
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What is the function of a thrust bearing? |
Prevent shaft from moving under end thrust |
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What are the two main types of plain thrust bearings? |
Flat plate Tapered land |
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What plain thrust bearing is good for heavier loads? Why? |
Tapered land Better lubrication, less contact pressure on start up |
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How are mating parts separated with anti-friction bearings? |
Precision rollers |
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What shapes can the rollers be? |
Round Cylindrical Barrel Tapered |
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What are the 3 main types of anti-friction bearings? |
Ball Roller Thrust |
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What are the five different types of ball bearings? |
Single row deep groove Double row deep groove Single row angular contact Double row angular contact Self-aligning |
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What are advantages of anti friction bearings? |
Very little friction No separate lube system Higher rpm |
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What’s one disadvantage of anti friction bearings? |
Require more room |
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What is the most common ball bearing? |
Single row deep groove |
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What kind of loads can the single row deep groove ball Bearing take? |
Primarily radial Moderate thrust |
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What loads can the double row deep groove ball bearing take? |
Higher radial than single row but no axial load capacity |
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Which type of ball bearing can handle axial loads but only in one direction and is often paired? |
Single row angular contact |
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Which ball bearing is meant for heavy radial and axial loads (both directions) but is slower and cannot tolerate misalignment? |
Double row angular contact |
