Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Industrial Mechanic 2nd Block, Harmonized > Alb. Mod. Plain Bearings > Flashcards

Alb. Mod. Plain Bearings Flashcards

1
Q

In regards to the journal, it is normally machined to _____ _______ than the rest of the shaft

A

Closer tolerances, in regards to dimensions and finish

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Plain bearings can be journal bearings, which support _____ loads

A

Radial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Plain bearings can be thrust bearings, which support _____ loads

A

axial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The two main functions of a journal bearing are: (2)

A
  • Hold a journal

- support radial load

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The 3 most common radial loads are: (3)

A
  • Stationary load
  • Oscillating load
  • Reciprocating load
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

_____ radial loads generally act in one direction and on one area of the bearing

A

Stationary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

_____ radial loads shift through an arc of less than 180°. The fluid film is much thinner, but stronger than a stationary load. Surface finish and oil cleanliness are more important than on a stationary load.

A

Oscillating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

____ radial loads shift 180° from one side of the bearing to the other. The fluid film is much thinner, but stronger than a stationary load. Surface finish and oil cleanliness are more important than on a stationary load.

A

Reciprocating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Journal bearings can either be: (2)

A

Split in half or

One piece, also called a bushing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Thin shell split bearings have the following features: (4)

A
  • Thin shell seated in a strong housing with accurate bore
  • Flexible
  • Thin overlay on steel backing (Most common overlay is babbitt)
  • Shell can have intermediate layers to assist bonding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Thin shell split bearings are a lightweight bearing that can withstand:

A

High loads

Note: Originally developed for automotive engines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Thin shell split bearings have a high load capacity because they are:

A

High precision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

This bearing is lightweight, has a compact housing, is quick to change out, and inexpensive to replace.

A

Thin shell split bearing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

This bearing has a consistent quality and is available in a wide range of materials. It is available in both oversize and undersizes, which allows the grinding of the journal for reuse.

A

Thin shell split bearing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

This split bearing may have a plain seat, or a spherical seat.

A

Thick wall split bearing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

With a thick wall split bearing designed with a spherical seat, the spherical seat assists with:

A

aligning a heavy shaft with the bore during installation. Simplifies installation and ensures edge loading of the bearing is minimized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Bushings are a type of plain bearing that has not been split and can be designed to handle what two loads? (2)

A

Radial

Axial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The load and speed capacity of bushings is comparable to:

A

The load and speed capacity of split bearings of the same size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Direction of load is normally radial, but some bushings can accommodate an axial load using: (2)

A

Flanges

Thrust washers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Bushings can be used in the same applications as split bearings, the choice depends upon: (2)

A
  • Ease of assembly

- parts on hand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

This type of bushing consists of a thin shell lined with a soft bearing material:

A

Wrapped bushing

Note: Only available in stock sizes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Wrapped bushings have a high:

A

Fatigue strength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Pre finished bushings should only be used in lightly loaded, non critical applications as there is:

A

Variation in the diameter after installation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

These bushings are bored out of a solid piece of bearing material, such as lead, bronze or teflon. Can be easily made for emergency repairs, and can accommodate deep lubrication grooves

A

Solid bushing

Note: Do not have the fatigue strength of wrapped bushings. Must be reamed to final diameter after installation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

This type of bushing consists of an outer bushing with a loosely fitted inner bushing.

A

Floating bushing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

This type of bushing can support a lightly loaded but high speed shaft, or be used with heavily loaded slow speed journals:

A

floating bushing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Water lubricated bushings are normally made from this material, since it is slippery when wet

A

Rubber

Note: In some applications, nylon or PTFE is used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Water is excellent for _________ which makes the water lubricated bushings very durable. Used when water is constantly flushing the bearings and makes retention of any other lubricant impossible.

A

Heat dissipation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are two limitations of water lubricated bushings? (2)

A
  • Only suitable for very light loads

- corrosion resistant journals must be used.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Why can you only use water lubricated bushings in a light load application?

A

Water has a very low film strength.

Note: These bushings can only be used, for example, on vertical shafts without side loads.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

____ bushings are either made from a porous material soaked with lubricant, or have a lining made with pockets of lubricant.

A

Pre lubricated bushings.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

A porous bronze bushing is also known as: (2)

A
  • Sintered bronze bushing

- Oilite bushing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

A porous bronze bushing is pre charged with oil by soaking the bushing in oil at ____ °C for ____ minutes

A

90 C (194 F) for 30 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

porous bronze can hold up to ____ % its volume in oil

A

30

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

With porous bronze bushings, the higher the oil capacity, the:

A

Lower the strength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Pre lubricated bushings are used where:

A

It is not practical to supply lubricant from the outside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Due to poor heat distribution, pre lubricated bushings are more suitable for:

A

Start/stop applications

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Pre lubricated bushings are not suitable for high temperatures, as the:

A

Oil evaporates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Pre lubricated bushings are intended for ___ loads

A

light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

____ bushings are made of a slippery material, such as graphite or PTFE. The can also be made of a bronze matrix containing graphite or PTFE, which oozes from the matrix under pressure

A

Dry lubricated bushings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are the features of dry lubricated bushings? (3)

A
  • Can be solid or lined
  • can run dry or with lubricant (increases speed rating)
  • Are available in a very large range of materials
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Dry lubricated bushings are ideal for these two situations: (2)

A
  • start and stop applications

- positions where lubrication is impossible, such as high heat areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Dry lubricated bushings are not suitable for: (2)

A
  • High speeds

- Heavy loads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

____ bearings are one of the most widely used types of plain bearing. Designed to develop a full film of lubricant when the journal is up to speed

A

hydrodynamic bearing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

A hydrodynamic bearing depends on the rotation of the shaft to drag the oil into the loaded area. It can be a split bearing or bushing. An oil inlet is located:

A

In the unloaded area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

In order for a hydrodynamic bearing to get a full film of lubricant under the loaded area, the journal must turn at a designated:

A

Minimum speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

With a hydrodynamic bearing, what happens when you run under the minimum speed?

A

The lubricant film breaks down and the journal contacts the bearing, resulting in severe wear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

With a hydrodynamic bearing, the ___ determines the minimum speed

A

load

49
Q

Most of the wear on a hydrodynamic bearing occurs:

A

at start up, before the supporting film has developed

50
Q

Hydrodynamic bearings can be designed to carry:

A

Any load at very high speeds

51
Q

The actual load on a hydrodynamic bearing can exceed 300 PSI and speeds can be up to 15000 f/m (80m/s). They can be designed to run at _____ RPM at lower loads

A

200, 000

52
Q

For steady loads that are moderate to heavy, hydrodynamic bearings usually have a plain circular bore with a chamfer at the area of the split, which:

A

assists in the formation of the oil wedge

Note: this is the most common design

53
Q

Bearings that reciprocate may include a ________ oil distribution groove, which reduces the load rating by about half, but provides a continuous supply of lubricant to all areas of the bearing

A

circumferential

54
Q

An ____ groove is sometimes used to ensure distribution of oil across the width of the bearing

A

axial groove

Note: slow speed bearings requiring grease lubrication also use axial/distribution grooves in the unloaded area

55
Q

An unsteady load at high speeds can develop a condition called:

A

Oil whirl

Causes oil whip, which results in the shaft breaking through the film and destroying the surface of the bearing

56
Q

What are two methods used to create oil wedges at different locations around the shaft to hold it in position, preventing oil whirl? (2)

A
  • Lobed bearing (light applications)
  • tilting pad style (heavier applications)

Note: clean oil is important for tilting pad style bearings, as deposits can form and seize the pads

57
Q

An added feature that became widely used on tilting pad bearings is:

A

directed lubrication

58
Q

directed lubrication has what 4 advantages over oil bath lubrication, on tilting pad bearings? (4)

A
  • reduces temperature of pads (20 C or 68 F)
  • Increases load capacity
  • reduces power consumption
  • reduces oil flow, smaller lube system can be used
59
Q

Plain hydrodynamic bearings can sometimes be found in: (4)

A
  • Turbines
  • Gearboxes
  • Engines
  • Compressors
60
Q

____ bearings are found in equipment which runs too slow to develop a hydrodynamic film

A

Hydrostatic

61
Q

Hydrostatic bearings require_____ to provide a pressurized film of lubricant to support the shaft

A

External pump

62
Q

This type of bearing can be a split bearing or a bushing. Oil is admitted through holes into pockets(recesses) in the loaded and unloaded areas. Holes are fitted with restrictors to regulate the pressure, and control shaft position within the bearing.

A

Hydrostatic bearing

63
Q

This bearing has no minimum speed, and results in no wear at startup

A

Hydrostatic bearing

64
Q

On a hydrostatic bearing, you can expect load and speed limits to be lower than a hydrodynamic bearing. This is due to:

A

Turbulence in the oil developing in the pockets as speed increases. Turbulence will reduce the film strength.

Note: very high loads can be supported if there is zero speed or only a few feet per minute

65
Q

Hydrostatic bearings are used where:

A

Shaft load may change suddenly, but position must be accurately maintained

66
Q

____ bearings are used with a heavy, unsteady load, in a compact area, where speeds aren’t sufficient for hydrodynamic lubrication

A

hydrostatic

67
Q

the _____ bearing is a special type of hydrostatic bearing with pressurized oil entering under the loaded area only

A

oil lift journal bearing

68
Q

the oil lift journal bearing uses hydrostatic pressure to lift the journal on startup, until:

A

hydrodynamic lubrication can take over

69
Q

Hybrid bearings depend on both hydrodynamic and hydrostatic lubrication, however can only support a full load when:

A

both are operating together

70
Q

hybrid bearings are used when there is an:

A

imbalance, such as an eccentric weight on a rotor increasing radial load as speed increases

71
Q

The function of a thrust bearing is to:

A

Hold a shaft axially in the required position

72
Q

a thrust bearing consists of:

A

one or multiple support surfaces perpendicular to the shaft axis

73
Q

With a thrust bearing, a ____ attached to the shaft rides against the thrust bearing to limit axial movement. This may also me forged and machined as part of the shaft.

A

thrust collar

74
Q

Various designs of thrust bearings are used, including: (3)

A
  • Flat plate
  • Tilting pad
  • Tapered land
75
Q

This type of thrust bearing is the simplest and cheapest to manufacture, and limited to light loads.

A

Flat plate

76
Q

With a vertically mounted flat plate thrust bearing, it can be oil submerged or oil fed, if it is oil fed, the feed should be to the:

A

inner diameter

77
Q

This thrust bearing is also referred to as a profiled pad thrust bearing. Provides a greater load capacity than flat plate, due to superior hydrodynamic lubrication. Has flat lands on the pad to prevent excessive pressure on start up.

A

Tapered land thrust bearing

78
Q

This thrust bearing is a stationary base ring fitted with tilting segments of bearing material. The thrust collar transmits the axial load to the tilting segments.

A

tilting pad thrust bearing

79
Q

the tilting pad thrust bearing is also known as: (2)

A

Kingsbury bearing

michell bearing

80
Q

The tilting pads on tilting pad bearings are made of:

A

Babbitt on a steel backing

81
Q

In regards to a tilting pad thrust bearing, the thrust collar performs what two functions?

A
  • Transmits thrust load

- Draws lubricant into loaded areas

82
Q

Some assemblies of a tilting pad thrust bearing include tilting pads on both sides, this is to:

A

provide thrust control in both directions

Note: often used with reversing loads

83
Q

On a tilting pad thrust bearing, directed lubrication replaces the oil bath with:

A

Spray nozzles between the pads

84
Q

On an oil lift thrust bearing, jacking oil is required to:

A

separate the pads from the thrust collar on start up, until higher speeds are achieved

Note: It is also required when there is a heavy load on a vertical shaft

85
Q

Special bearings are bearings that support the journal with something other than oil or grease, such as: (2)

A
  • Gas

- Magnetic field

86
Q

Magnetic bearings now perform better than:

A

Oil bearings

87
Q

Gas can be used instead of oil in what applications?

A

light load high speed applications

88
Q

Wear resistance decreases as ______ increases

A

compressive strength

89
Q

_____ is the resistance of a material to flaking and cracking by loads that increase and decrease in rapid cycles

A

fatigue resistance

Can be increased by keeping the liner material as thin as possible, to allow the backing material to take the stress

90
Q

_____ determines how well a material handles contaminants without failing

A

embeddability

91
Q

_____ allows a material to yield to misalignment or imperfections in the shaft. ensures all parts of a bearing share the load.

A

Deformability (conformability)

92
Q

____ is a materials ability to retain a film of lubricant

A

wetability

93
Q

____ allows rapid transfer of heat

A

good thermal conductivity

94
Q

____ allows a material to resist wear from the acids in oxidized oils

A

good corrosion resistance

95
Q

____ is a materials ability to bond to a backing material

A

bondability

96
Q

Materials in a journal and bearing must be ____ to ensure parts don’t seize or weld.

A

compatible

97
Q

____ is used for light duty bushings, and is used in a bronze matric for extra strength. It is self lubricating, chemically inert, and can be used with soft journals. It’s limited by temperature, absorbs water, and emits a poisonous gas when burned

A

Teflon

98
Q

aluminum/___ and aluminum/___ alloys were developed specifically for bearings.

A

tin, silicone

99
Q

the aluminum/___ alloy consists of free ___ in an aluminum matrix.

A

Tin.

Note: tin provides the bearing material and the aluminum provides the strength.

100
Q

The aluminum/silicone alloy was developed for:

A

extra strength

101
Q

____ bearing materials are more embeddable and more corrosion resistant than copper/lead or lead bronze, less expensive and can run with softer shafts than copper or bronze alloys, have a higher load rating than babbitt, and can be bonded to steel backings

A

aluminum/tin and aluminum/silicone

Note: Less conformability and less embeddability than babbitt

102
Q

A small chip or burr in a housing can cause ___ when seating a bearing in a housing

A

false loading

103
Q

____ is the distance that a new insert protrudes above a split line of a housing

A

crush

104
Q

____ is the amount that the insert diameter is wider than the bearing house diameter

A

Spread

105
Q

The coating in the housing is required to prevent ___ from migrating out of the casting and destroying the bearing, as well as preventing corrosion

A

sand

106
Q

To check if a journal is out of round:

A

three measurements are taken at 60° intervals

107
Q

To check if a journal has developed a taper:

A

three measurements are taken at 60° intervals at both ends and the middle of the journal

108
Q

When installing a bearing, the insert should be cleaned and ____

A

lightly lubricated

109
Q

When installing or removing a bushing, what tool can help avoid damaging the bushing and the housing?

A

Adapter and Driver

110
Q

What could you do to repair a damaged bore before installing a bushing?

A

bore the housing oversize and sleeve it

111
Q

What two things can help with installation of a bushing?

A

Lightly lubricate the bushing, and slightly chamfer the outside and inside edges of the bushing

112
Q

A solid bushing almost always has to be ____ to its final diameter, after installation

A

reamed

113
Q

Thrust collars must be checked for ____ with a dial indicator

A

runout

114
Q

____ and ____ is never recommended with oilite bearings.

A

Honing and grinding.

Note: use a sharp cutting tool instead

115
Q

When scraping babbitt for a smooth surface contact area, you want to repeat until you have points of contact at least 1/8” in diameter, over at least ____ % of the bearing

A

85%

116
Q

Correct ____ in a journal bearing is critical to the formation of an oil film

A

clearance

117
Q

When checking clearance, is a lift check, aka bump check, considered accurate?

A

No.

But it will show if the bearing is worn and needs further attention

118
Q

What is the most accurate way of checking clearance?

A

Measure the bearing bore and journal with a vernier micrometer. Subtract journal diameter from bore diameter to calculate clearance.

119
Q

How would you adjust clearance on a connecting rod bearing housing?

A

shims

Industrial Mechanic 2nd Block, Harmonized (28 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions