couplings Flashcards
three basic couplings are?
rigid
flexible
special purpose couplings
types of rigid couplings?
sleeve couplings
compression couplings
ribbed couplings
flange faced couplings
threaded couplings
When Riggid couplings are not actually a line, they can cause, what?
vibration problems and bearing ,seal or coupling failure
compression couplings are often used when the coupling must be ?
removed or installed often
Shaft couplings are power transmission components used to connect what?
connect the driving and driven shafts end to end
where are sleeved couplings used ?
low speeds and low torque applications , key way in bore and set screws.
compression couplings grip the shaft by using ?
tapered sleeves in tapered hubs don’t not require keys or splines
where are ribbed couplings used?
used in heavy load and torque services can be made of steel or cast iron
ribbed coupling fit shafts of what sizes?
1” to 7” often used to connect line shafting
rigid multi bore couplings are used to connect shaft of unequal diameter true or false
true
flange face couplings are used to attach what size shaft diameter
same size shafts or different diameter shafts
flexible couplings are classified in 3 ways
-mechanical flexabiltiy
-material flexibitliy
-combination of material and mechanical flexibility
types of mechanically flexible couplings?
roller chain
silent chain
synthetic chain
gear
mechanical flexibility couplings are metal and lubrication is required to reduce?
wear with in the coupling
what are the main advantages of silent chain couplings
ability to perform smoothly and quietly and remain in balance at high rotationl speeds
Gear couplings, have mechanical flexibility, because of the clearance between what?
clearance between the teeth and shape of the teeth
Where are synthetic chain couplings used?
light power transmission drives
used where oil or grease are not desirable
What two types of roller chain are used for chain couplings
most common -double strand roller chain
-single strand roller chain-provides more end float
What couplings are usually made of steel and can transmit extremely high torque loads at high rpm?
gear couplings
What are the advantages of material flexible couplings
thye do not require lubriction
provide smooth uniform power,
Grease is recommended for the majority of gear couplings in applications, but slow speed drives may use?
heavy oil
What is a rubber tire coupling used to reduce?
vibration and shock
allows for any type of misalignment and end float
Metal disc couplings use a series of thin ___ to form a flexible steel disk
steel plates
metal disc coupling
if a single set of disks are used they tolerate angular misalignment but if two sets of disks are used they compensate for both angular and ?
and offset
Where are jaw and spider couplings used?
small to medium hp applications
what coupling is recommended for high speed operation temperatures and high torque applications ?
metal disk couplings
What coupling has high torsional flexibility, can tolerate shock loads, reversing, and dampen vibration and allows some shaft misalignment and tolerates considerable axial movements. It also offers excellent resistance to electrical conductivity and requires no lube and can be used in the food industry or in corrosive atmosphere.
splined rubber coupling
Why are flexible? Coupling the most common couplings in the industrial application?
Because they compensate for some misalignment, which is a major advantage over a rigid coupling’s
What are some desirable power transmission characteristics of centralfugal couplings?
soft start
smooth acceleration
overload protection
dampening shock loads
what is soft start on a centrifugal coupling?
allows driver to approach running speed before applying load
what is smooth acceleration on a central fugal coupling?
allows load to smoothly accelerate with out no shock to the driven unit
what is overload protection on centrifugal design couplings
driver will not stall but there will be slippage between driver and driven units
a fluid coupling consists of two operating members what are they
the impeller (pump)
turbine (runner)
what is dampening shock load
Is achieved because of slight slippage or no positive mechanical connection is made with central fugal design couplings
during start up the fluid coupling has high ?
vortex flow
when the fluid coupling is running under normal conditions there is some slip , the amount of slip can be ?
2%-6%
Most fluid coupling manufactures, recommend that the couplings be filled to a maximum of?
80% of their total capacity
true or false the fluid coupling cannot tolerate any misalignment or end float because each part is held to close tolerances
true
centrifugal shoe couplings use mechanical contact between the ?
friction shoes and the drum but application is by centrifugal force
the correct shaft alignment is important an central shoe couplings because ?
any misalignment causes vibration uneven contact and wear on friction. surfaces and reduced power transfer
where is a floating shaft coupling used ?
used where the drive component cannot be located close to the driving motor or where space is required for maintenance
where are spacer couplings use d?
used where the coupling is frequently removed for certain maintenance to equipment
does not alter shaft alignment
what is service factor rating ?
the life expectancy and use of a part under certain types of conditions like shock loading continuous maximum power use and other operating conditions
true or false
for a given horse power as the speed (rpm) decreases the torque transmitted with in the unit increases ?
true
In order to extend bearing life and to reduce vibration throughout, the machine is highly recommended that high speed couplings over_____ are dynamically balanced ?
3600 rpm
what are some couplings used for high hp couplings
gear couplings
universal joint
silent chain
flange face couplings
flexible metal disc couplings
some common used low hp couplings are ?
sleeve couplings
roller chain
rubber tire
steel grid
jaw and spider
splinter rubber couplings
name three types of shaft misalignment to be aware of when installing couplings
offset
angular combination of offset and angular misalignment
see pic for alignment
what causes axial movement
thermal growth
for steel hubs heat to what temp?
heat to 180F above ambient temp for every 0.001 of interference per inch of hub diameter
oil bath heating is limited to what temp?
300f because of flammability
use a temp stick or thermometer
what is the best heating method for tapper fit couplings
ovens or oil baths
split couplings must have sufficient gap between top and bottom halves it is aprox?
1/16-1/8 inch on each side
If no puller holes, it may be possible to drill the hub and tap it with holes how far apart should the holes be so the balance of the coupling is not changed
180 deg apart
