Post on 13-Jan-2016
www.engineersportal.in
Introduction.Overview: Why Used?Belt Drives.Types of Belt Drives.Design for Belt Drives.Chain Drives.Terminology for Chain Drives.Difference B/W Belt Drives & Chain Drives.Conclusion
www.engineersportal.in
The belt drives or chain drives are mainly used for transmitting the power from one shaft to other when they are running at different speed or either at same speed .
www.engineersportal.in
Transfer power or torque from one location to another i.e. From driver: motor, peddles, engine, windmill, turbine to driven: conveyor belt, back wheels/ bike.
Used to span large distances. Gear drives have a higher torque capability but not flexible or cheap.
Often used as torque increaser & speed reducer, max speed ratio (3.5:1).
When Positive drive is required.
www.engineersportal.in
This are the power transmitting device.
This is based upon the velocity of belt, arc of contact b/w belt & smaller pulley.
Material used for belt may be leather, cotton, rubber etc.
Slip & creep.
www.engineersportal.in
*A/C to velocity of drive *A/C to geometry*Light *Flat belts*Medium *V- belts*Heavy *Trapezoidal *Curvilinear
& Rounded
www.engineersportal.in
www.engineersportal.in
www.engineersportal.in
1. COVER
2. INSULATING COMPOUND
3.TENSION MEMBER
4. COMPRESSION AREA
www.engineersportal.in
ADVANTAGES
Positive drive due to no sleep.
High velocity ratio is high (10).
More power transmission
Longer life.
DISADVANTAGES
Complicated construction.
Not to be used in large center radius.
Produce certain amount of creep.
www.engineersportal.in
1
2
2
1
22112211 22
D
D
DDRRb
Belt speed (no slipping)
Speed ratio
Pitch dia. of sheaves
www.engineersportal.in
Belt length:(Open belt drives)
Center Distance:
x
DDDDxL
4
)1()(
22
22
21
)/(sin)21( rrx
www.engineersportal.in
21801 21802
Motor Nameplate
Center Distance(center shaft to center
shaft)
SizeSize
www.engineersportal.in
www.engineersportal.in
www.engineersportal.in
To avoid sleep & creep used steel chain.
Perfect velocity ratio is obtained.
Used for both long & short length.
Produce less load on shaft & more power.
Withstand at any temperature & atmospheric condition.
www.engineersportal.in
PITCH
SPROCKETS
PITCH CIRCLE DIAMETER.
www.engineersportal.in
Calculate Velocity Ratio
i
o
o
i
T
T
n
nVR
n = speedT = teeth
www.engineersportal.in
Length of chain drives
)/(4
)(
2/2)(
2
21212 xpTTTT
pxpitchesL
2
212
2
1212
4
)(8
224 TTTT
KTT
Kp
x
www.engineersportal.in
Hoisting & hauling(with square & oval links).
Conveyor chain (hook joint & closed joint type).
Bush roller chain
www.engineersportal.in
CHAIN DRIVE
Used When:
Speed:
Dis:
Advs:
High Speed, Low T High T, Low Speed
2500 < Vt < 7000 ft./min.
V < 1500 ft./min.
Must design with standard lengths, wear, creep, corrosive environment, slip, temp., when must have tension need idler
Must be lubricated, wear, noise, weight, vibration
Quiet, flexible, cost Strength, length flexibility
www.engineersportal.in
www.engineersportal.in
THANKS FOR YOUR ATTENTION
www.engineersportal.in