Alignment
A condition where the axis or center lines of two shafts are in line or
coaxial.
Angular Misalignment
A condition where two shafts are not parallel. The axis or center lines
of two shafts intersect at angles to each other.
Axial Expansion
This is a lengthening of a shaft. It could be caused by thermal changes
in environment or induced through the use of a sliding coupling.
Backlash
A jarring reaction when starting or reversing a load, caused by play in
a coupling.
Clearance Fit
Also called a slip fit. This is the most popular fit because of its ease
of installation. The bore is larger than the shaft. It maintains its position
on the shaft through the use of a key and set screw.
Damping
Reducing vibration.
Donut
The elastomeric element in donut type elastomeric couplings.
Elastomeric
A coupling that has resilient materials through which the power is transmitted.
They are in some way attached to the coupling halves. They are usually
made of rubber, synthetic rubber or plastic materials.
End Float
Also called axial misalignment. It is a condition where shafts could be
in angular and parallel alignment. However, the shafts move in and out
relative to each other.
Horsepower
The rate at which torque is applied. Since applied torque causes a shaft
and its connected components to rotate, a certain RPM results. HP is calculated
by the following equation:
HP =
Torque (lb. -in.) x RPM
63,025
Inertia
The tendency of matter to remain at rest, or if moving, to keep moving
in the same direction. Examples of high inertia loads; fans and fly wheels.
Interference Fit
Also called a shrink or press fit. It gets its name because the bore is
actually smaller than the shaft it is to be mated with. It is the strongest
fit possible but requires heat or an hydraulic press to install
Parallel Misalignment
A condition where the shaft axis or center lines of two shafts are parallel
but offset from each other.
Shear Pin
A protection device used on some couplings. To protect driver and driven
equipment against overload. The pin is located between coupling halves
and is machined to break or shear at a predetermined load allowing the
driver side to free wheel
Spider
The elastomeric element of a flexible jaw type coupling. Usually has
4 or 6 arms.
Shrouded Bolt
The optional bolt arrangement available on rigid and gear couplings. It
is used in very high speed applications. Bolts are installed with a socket
wrench.
Thermal Expansion
Lengthening of shafting caused by thermal changes in environment.
Torque
The force required to turn a shaft multiplied by the radius at which the
force is applied. Torque is calculated by the following equation:
Lb. In. Torque = Force (lb.)
x Radius (in.)
Torsional Vibration
There are two main kinds of torsional vibration: a continuous steady form
that comes from reciprocating engines and an intermittent for in that comes
from large synchronous electric motors or from the driven equipment side
in steel rolling mills. |
