Gear Couplings
Gear
couplings also play a very important role in the gear performance. A
properly functioning gear coupling is a must for success in any gearing
system. Essentially Gear couplings are the mechanical devices that is used
for transmission of torque between two shafts that are not coaxial. It
consists of a flexible joint that is fixed to each shaft. Next, a third
shaft called spindle connects the two joints.
The importance of Gear coupling in a peak gear performance can be gauged
from the view point of backlash that the gear coupling shows. The gear teeth
in a typical gear coupling displays a high backlash for allowing angular
Misalignment. Gear couplings can compensate for the
Misalignment
through the clearance between the gear teeth.
A properly designed gear couplings is supposed to absorb the misalignment
forces. This way more costly, vital and sensitive components can be saved
from any harm.
Types of Gear Couplings
- Flexible Couplings
The advantages of Flexible couplings makes them a preferred choice for
many applications. They offer easy installation, no requirement of
lubrication, no maintenance requirements, and noise free operation.
- Chain Couplings
Chain couplings though not exactly a gear coupling but operate
similarly to a gear coupling. Here Sprockets on each of the shaft end
get connected by a roller chain. Loading is also identical as that in
chain couplings.
- Grid Couplings
Grid couplings typically use corrugated steel grids, which bends to
compensate for the loading that is induced by misalignment.
- Solid and magnetic coupling
Solid and magnetic couplings does not necessitate the need for
lubrication. Solid couplings are essentially rigid structures. They do
not compensate for misalignment. They allow two shafts to be connected
for the transmission of torque. An example of magnetic coupling is the
machine that has bolted hubs keyed onto shafts.
Features of Gear
Couplings
An ideal gear coupling should show the following properties:
- A high torque
- No backlash
- High RPM that is balanced to AGMA classes
- Reduce vibration
- Size must be Space-saving size
- Low weight
- High torque capacity
- Must be Torsionally stiff
- A large variety of shaft attachment designs
Misalignment of Gear Coupling
Misalignment can occur as an offset or as an angular displacement taking
place on two of the three axes. Though the third axis, that is in the
longitudinal direction, is commonly not measured, bit errors typically in
this direction can cause constant and tremendous thrust loads in the system.
The following image shows different types of Misalignment:
