plain bearings Flashcards
What are two types of plain bearings?
Journal and thrust bearing
What are the two main functions of journal bearings?
To support radial load and hold the journal in location accordingly
It’s hydrodynamic bearing suitable for slow speed? Why our why not?
No, because the oil wedge will not develop.
What must be done before start up to ensure there is no damage to an oil lift bearing?
Jacking oil must be brought up to pressure.
Why is circumferential groove required in reciprocating plain bearings?
To distribute the lubricant.
List four advantage of Babbitt as a plain bearing material?
High wettability, inexpensive,excellent bondablity, good corrosion resistance, high embeddability, good thermal conductivity.
How do you check the contact area of a bearing?
By lightly coating the journal with Prussian. Blue and rotating it inside the shell.
How can clearance be adjusted on some connecting rods?
With shims
Stationary load means?
One direction (gravity)
Oscillating load means?
Load changes less than 180°
Reciprocating load means?
Load changes more than 180°
3 type of radial loads?
Stationary,oscillating,reciprocating
Types of radial bearings?
Split bearing (thin shell type)
Split bearing(thick wall construction) and spherical seat
Types of bushings?
Wrapped bushing, solid bushing, floating bushing, water lubricated, pre lubricated,dry lubricated,
Wrapped bushing have high fatigue strength true or false?
True
Solid bushing they can accommodate deep lubricant grooves. True or false
True
Floating bushings supports lightly loaded high speeds shafts such as turbo charges. True or false
True
The porous bronze bushing also called sintered or oilite bushing is pre charge with oil by soaking the bushing in oil at ___°C or ___ °F for half hr
90°c or 194°F
What are dry lubricated bushing made of slippery material such as?
Graphite or PTFE
Hydrodynamic bearings are one of the most widely used types of plain bearing? True or false
True
Bearings that reciprocate may include a circumferential oil distribution groove in the middle of the bearing. This groove actually reduces the load rating to about 1/2? True or false
True
What is oil whip?
Unsteady load at high speed
Plain hydrodynamic bearings are commonly used in?
Turbines of all sizes, gearboxes of all sizes, engines of all sizes, compressors of all sizes and types.
Hydrostatic bearings there it’s no minimum speed a load supporting film can be provided at zero speed.True or false?
True
Hydrostatic bearings ensures no wear at start up true or false?
True
Hydrostatic bearings are used where the shaft load may change suddenly, but shaft position must be accurately maintained?True or false?
True
Hybrid bearings they can support a full load only when both hydrodynamic action and hydrostatic action are operating together? True or false
True
Types of thrust bearings?
Flate plate,tapered land,tilting pad.
What the function of a thrust bearing?
To hold a shaft axial in the required position
The tilting pad thrust bearing it’s also known as what?
Kingsbury bearing
Babbitt, also be referred to as a white metal alloy, is composed of soft alloys such as?
Tin, lead, copper,antimony.
