gear coupling industrial design ahmedawad
DESCRIPTION
designTRANSCRIPT
LOGO
Gear CouplingPMANF-2014
Contents
What is Coupling ?1
Types of Coupling2
Gear Coupling 3
Basic Principle4
Machine gear shaping, Assembly , 3D drawing5
load calculations 6
Contents (continue)
Catalogs9
Misalignment 8
Crowned Gear Tooth7
Types of gear coupling8
Advantages and disadvantages9
What is Coupling ?
A coupling is a device used to connect two
shafts together at their ends for the purpose
of transmitting power.
The primary purpose of couplings is to join
two pieces of rotating equipment while
permitting some degree of misalignment or
end movement or both.
Diagram
rigid couplings
are the most
effective choice
for precise
alignment and
secure hold.
Flexible couplings
are used to transmit
torque from one shaft
to another when the
two shafts are slightly
misaligned. Flexible
couplings can
accommodate varying
degrees of
misalignment up to 3°
Coupling
Requirements of good shaft alignment/ good coupling setup
it should be easy to connect or disconnect the coupling.
it does allow some misalignment between the two
adjacent shaft rotation axes.
it is the goal to minimize the remaining misalignment in
running operation to maximize power transmission and to
maximize machine runtime (coupling and bearing and
sealing lifetime).
it should have no projecting parts.
it is recommended to use manufacturer's alignment target
values to set up the machine train to a defined non-zero
alignment, due to the fact that later when the machine is
at operation temperature the alignment condition is
perfect
Gear Coupling
A gear coupling is a mechanical device for transmitting
torque between two shafts that are not collinear.
Each joint consists of a 1:1 gear ratio internal/external
gear pair. The tooth flanks and outer diameter of the
external gear are crowned to allow for angular
displacement between the two gears. Mechanically, the
gears are equivalent to rotating splines with modified
profiles.
Gear couplings are generally limited to angular
misalignments, i.e., the angle of the spindle relative
to the axes of the connected shafts, of 4-5°
Basic Principle
The function of the gear coupling is to connect two
shafts. The gear coupling consists of two inside
metal gear halves each connecting to one shaft and
to the external gear, and a metal external gear
connecting the inside gears.
Gear Couplings are best suited for heavy load, slow
speed applications.
Diagram
shaft
key
External
teethed
forged
hubs Internal
teethed
Forged
sleeves
bolts
Uses
Shaft couplings are used in machinery for several
purposes, the most common of which are the following:
To provide for the connection of shafts of units that
are manufactured separately such as a motor and
generator and to provide for disconnection for
repairs or alterations.
To provide for misalignment of the shafts or to
introduce mechanical flexibility.
To reduce the transmission of shock loads from
one shaft to another.
To introduce protection against overloads.
To alter the vibration characteristics of rotating units.
Approved materials
Shafts, pinions, wheels and wheel rims of
gears in the main propulsion plant are
preferably to be made of forged steel. Rolled
steel bar may also be used for plain,
flangeless shafts. Gear wheel bodies may
be made of grey cast iron , nodular cast iron
or may be fabricated from welded steel
plates with steel or cast steel hubs.
Machine gear shaping a gear coupling sleeve
Assembly
3D drawing
Fully Crowned Gear Tooth
Fully-Crowned Tooth represents the ultimate
achievement in the art of gear tooth design, wherein all
three working portions of the tooth are crowned. As a
result, the teeth act much like a rocking chair, capable
of sliding freely in the axial direction without digging or
gouging the internal mating teeth.
Crowned Flanks : Flanks of
the teeth are crowned so that
tooth thickness is greatest at
that center of the tooth. This
assures larger contact area per
tooth for higher torque
requirements and puts more
teeth in contact for a given
angle. Actual tooth loading
takes place near the center of
the tooth face where tooth
thickness is greatest, Crowned
flanks also eliminate end-of-
tooth loading, provide optimum
load distribution, and
accommodate all types of
misalignment with minimum
backlash.
Crowned Tips : Tips of
teeth are crowned. The
crowned tip contacts the
root of internal gear teeth
in the external sleeve,
accurately piloting the
sleeve with true concentric
ball-and-socket action. This
allows minimum diametric
sleeve clearance and
centers the sleeve
physically to assure good
dynamic balance
characteristics under
various loading and
misalignment conditions.
Crowned Chamfers :
Faces of the teeth
adjacent to the tips
are chamfered to
eliminate interference
with the sleeve tooth
fillets. This allows the
true involute flanks of
the gear teeth to be in
contact with the
sleeve teeth and
assures freedom to
misalign.
Tooth forms in the Coupling
Three types of external teeth are used in gear couplings.
Straight Teeth: The external teeth in the hub are straight.
During the condition of misalignment in the coupling the
contact pattern between the internal gear and the external
gear tends to be line type of contact as shown in the figure.
Crowning with constant radius: The external teeth are
barrel shaped with a constant radius in order to increase
the area of contact and move the area of contact to a near
middle portion of the teeth.
Crowning with variable radius: The external teeth are barrel
shaped with a variable radius instead of constant radius.
This increases the area of the contact significantly
compared to that of the constant radius crowning.
Types of gear coupling
FULL GEAR COUPLINGS HALF GEAR COUPLINGS MOTOR TYPE
GEAR COUPLINGS
Types of gear coupling
FLOATING SHAFT TYPE
GEAR COUPLINGSSPACER TYPE
GEAR COUPLINGS
Selection procedure for gear couplingDetermine transmitted Torque or Effective kW/rpm
𝐓𝐨𝐫𝐪𝐮𝐞 𝐞𝐟𝐟𝐞𝐜𝐭𝐢𝐯𝐞 =𝟗𝟓𝟓𝟎 𝐗 𝐤𝐖 𝐓𝐫𝐚𝐧𝐬𝐦𝐢𝐭𝐭𝐞𝐝 𝐗 𝐒𝐞𝐫𝐯𝐢𝐜𝐞 𝐅𝐚𝐜𝐭𝐨𝐫
𝐫𝐩𝐦
2) Shaft Diameter
Next check whether the shaft diameters of the driving and driven
equipment lie within the listed maximum bore. If not, go for a
bigger size of coupling which will be accommodating the shaft
diameter.
3) Maximum Speed of Application
Check whether the required speed of the shaft/coupling is within
the speed values applicable for the selected coupling size. These
speeds are given only as a guide since the maximum speed
depends on the system characteristics.
4) Space Limitations
To check space limitations dimensions of the selected coupling
should be compared with space provided in the application to
assure proper clearances. Shaft extensions, separation and
clearances to align coupling should be checked.
Misalignment
Spacer Gear Couplings
This type are designed to accommodate angular & parallel
misalignment or a combination of both. Besides this, it can
also accommodate axial misalignment (end float).
Custom built Gear Spacer Couplings and Torsion Shaft Gear Couplings are
also manufactured & supplied as per requirements
Advantages
Text
Advantages
Text
•Allows
freedom of
axial
movement
•High
transmission
efficiency
* Capable of
operating at
high speeds
* Full Teeth
engagement
– Reduces
uneven wear
Text
Text
Low overhung weight,
Compact.
* Good balance characteristics
* Generally used up to 120°C.
Disadvantages
1
Requires
lubrication.
Temperatur
e limitation
due to
lubricant
2
Separation
of greases
into soaps
and oils
3
Centrifugal
effect on oils
/ sludge
formation
Continuous and flanged sleeve gear
couplings are known for serve
applications involving extended
distances between shaft ends, mill
motors, and limited end float
situations.
Application
Steel Mill
installed on chain conveyor system
widely used in steel mill ,thousands
of couplings construct production
line of steel mill.
Conveyor System
wildly used on crane or
conveyor system.
Gear coupling with disc as
main transmitting shaft.
LOGO