Mech. Drives & Transmission used in Textile process machines

1. MECHANICAL DRIVES &
TRANSMISSION USED FOR TEXTILE
PROCESS MACHINES
BY
UMESH PATEL.[AGM
ENGG]HIMATSINGKA,[9980017879]
<umeshpatel123@yahoo.com>

2. SHAFT
Shaft is rotating m/c element used to transmit power
from one place to another
AXLE
Axle is a stationery m/c element used for
transmission of bending moment only eg: idler shaft
Spindle
Spindle is a short shaft
STD size
25 mm to 60 mm with 5 mm steps
60 to 110 with 10 mm steps and so on

3. STRESSES IN SHAFT
•Shear stress : due to torsional load
•Bending stress : due to forces acting upon
m/c elements like gears, pulleys etc
•Combined of both above
Material for shaft :
MS, Alloy steel using nickle, chrome & chrome
vanadium for high strength

4. Governing Equation for shaft
P = 2πNT / 4500
P ∞ N and T
Where, P= power ( HP) of shaft
N= speed in rpm
T= twisting moment
T =
T ∞
Fs = shear stress for shaft material ( depends on material)
d = shaft dia.

5. KEYS & COUPLINGS

6. • KEY
A piece of MS inserted between shaft and
pulley. Keys are temporary fastenings and are
subjected to crushing and shearing stress.
TYPE
• Rectangular & square keys
• Gib Head keys ( Head at one end )
• Feather keys ( key fastened with shaft )
• Wood ruff key ( easily adjustable , Tilting keys)
• Splines

7. Square Key
Provided half in the keyway of shaft &
half in keyway of hub or boss of pulley
Governing equation:
w = t = D/4
SPLINES
The spline shaft are used when the
force to be transmitted is large in
proportion to the size of shaft usually
4,6,10,16 splines are used.

8. COUPLINGS
• SHAFT COUPLING
A coupling is a device used to connect two shafts together at
their ends for the purpose of transmitting power.
• PURPOSE OF SHAFT COUPLING
To provide for the connection of shafts of units such as a
motor and generator .
To provide for misalignment of the shafts or to introduce
mechanical flexibility.
To introduce protection against overloads.
• REQUIREMENT OF GOOD SHAFT COUPLING
It should be easy to connect or disconnect the coupling.
It should hold the shaft in perfect alignment
It should have no projecting parts.

9. • FAILURE OF COUPLING
Improper installation
Poor coupling selection
Operation beyond design capabilities.
• COUPLING CHECK
Understand what caused the failure and to correct before
fixing new coupling. Some external signs :
Abnormal noise, such as screeching, squealing or chattering
Excessive vibration or wobble
Failed seals indicated by lubricant leakage or contamination
• LoopHoles
• Overweight / underweight of use of coupling in case of
N.A
• Projecting bolts /studs

14. BELTS & CHAINS

15. BELTS
• A belt is used to mechanically link two or more
rotating shafts.
Belts may be used as a source of motion, to
transmit power efficiently.
Belts are the cheapest equip. for power
transmission between shafts that may not be
axially aligned.
• Pros and cons
Belt drive is simple, inexpensive, and does not
require axially aligned shafts. It helps protect the
machinery from overload and jam, and damps
and isolates noise and vibration

16. BELTS
• VEE BELTS
They provide the best
combination of traction,
speed of movement,
load of the bearings,
and long service life.
They are cross-section
shape is trapezoidal
(hence the name "V").
• TIMING BELTS
(also known as toothed,
notch, cog, or
synchronous belts) are
a positive transfer belt.
When correctly
tensioned, they have no
slippage, run at
constant speed.

18. CHAINS
• Chain drive is a way of transmitting mechanical power from
one place to another.
The power is conveyed by a roller chain or transmission
chain passing over a sprocket gear, with the teeth of the
gear meshing with the holes in the links of the chain.
• By varying the diameter of the input and output gears with
respect to each other, the gear ratio can be altered
• Chains versus belts
Roller chain and sprockets is a very efficient method of
power transmission compared to belts, with less frictional
loss.
Drive belts can slip..

26. GEARBOX

27. GEARS & TYPES
• A GEAR is a rotating part having cut teeth, or cogs, which
mesh with another toothed part in order to transmit torque.
Geared devices can change the speed, torque, and direction .
Spur gears are simplest type of gear. They consist the teeth
projecting radially,. These gears can be meshed if they are
fitted to parallel shafts.
Helical The leading edges of the teeth are not parallel to the
axis of rotation, but are set at an angle. Since the gear is
curved, this angling causes the tooth shape to be a segment
of a helix. Helical gears can be meshed in parallel or crossed
orientations.
Spur gears are used for low speed applications and where
noise control is not a problem, the use of helical gears
involves high speeds, large power transmission.[
Double helical gears, or herringbone gears, overcome the
problem of axial thrust presented by "single" helical gears, by
having two sets of teeth that are set in a V shape.

28. GEARS & TYPES• A bevel gear is shaped like a right circular cone with most of its tip
cut off. When two bevel gears mesh, their imaginary vertices must
occupy the same point. Their shaft axes also intersect at this point,
forming an arbitrary non-straight angle .
• Spiral bevel gear teeth are curved along the tooth's length and set
at an angle, which are curved along their length, but not angled.
Straight bevel gears are generally used only at speeds below 5 m/s
• Backlash defines it as the maximum distance through which one
part of something can be moved without moving a connected part
or a clearance between mating components, or the amount of lost
motion due to clearance.
Theoretically, the backlash should be zero, but in actual practice
some backlash must be allowed to prevent jamming

41. GEARBOX LUB.& MAINTANANCE

42. What Causes a Short Life for Gear Oil?
Lubricant after too long time / scarce oil quatity
in a high-duty gearbox; it oxidized and
converts into sludge.

45. Worm Gears
They can transmit high loads at high-speed ratios. Ratios of 20:1 up to 60:1
• Worm drives are inefficient because the gears experience sliding rather
than rolling contacts, leading to operating temperatures much higher than
other gear types. Spur gears operate at (28°C) while worm gear
temperatures (50°C)
• factors affect worm gear efficiency:
Lead angle of the worm
Sliding speed
Lubricant
Surface quality
Installation conditions
• Worm Gear Lube Types
• Extreme Pressure (EP) Gear Oils
EP mineral gear oils are used extensively in worm gears
• Synthetic Worm Gear Oils
They possess superior lubricity properties and have good low and high
temperature properties.

46. RANGE : 0.05 HP to 90 HP.
REDUCTION RATIO : 5:1, to 70:1. Also higher ratio
100:1 to 4900:1 can be given on Double
Reduction.
WORM : The worm is Solid with shaft made of
high grade alloy steel gives hard wear resisting
surface duly case hardened.
WORMWHEEL : made of centrifugally cast
Phosphor Bronze rim shrunk

48. How to Inspect a Gearbox
• [a] Good Housekeeping is Essential
Many gearboxes operate in dirty environments
during inspection which may mislead to oil level,
ventilation plug, etc.
• [b] Walkaround Visual Inspection
Before cleaning the gear housing, inspect it for
signs of overheating, corrosion, contamination,
oil leaks and damage.
Measure the tightening torque of structural
fasteners that carry significant loads such as
torque arm bolts.

49. Detecting Overheating
1. Smoke from shafts, seals or breathers
2. Discolored or burnt paint on housings
3. Low oil level in sight glass or on dipstick
4. Dark oil in sight glass or on dipstick
5. Foam in sight glass
6. Water in sight glass or sludge on filter element (may
indicate oil cooler failure)
7. Measure gearbox sound and vibration and compare
to allowable limits.
8. Measure Temperature of casing by RTD / thermo
gauge

50. • Check Shaft Seals
If there is oil leakages at the shaft seals, probably
ingression of dust and water. If the gearbox has
labyrinth seals, it should have external seals such as V-
rings to prevent contaminant ingression.
• What to Look for
Watch for heavy contact at the edges of the contact
area, Severe misalignment usually causes macropitting.

55. bib
Biggest Gear box seen on
Morrison mercerise m/c

56. P.I.V : Positive power transmission yet
infinitely variable stepless speed
control.
• The chain is made from steel slats and is free to
move sidewise
When the wheels are close together the chain
operates around a large diameter.
• The principle - varying the driving and driven
diameters - is the principle on which all variable
speed drives

57. For long life -correct chain tension and oil level.

59. DESIGN CRITERIA FOR GEARBOX