Belt Drives
➢ Introduction
❖ Introduction to belt drives
❖ Advantages & disadvantages
❖ Types of belts & applications
❖ Belt configurations
❖ Materials used for belts
➢Velocity Ratio of belt drives
➢Slip of belt
H
➢Geometry of belts
❖ Open belt configuration
❖ Crossed belt configuration
S
➢Analysis of belt tensions
➢Power transmission in belt drives
Mechanicl Drives
W
⑰
Types of mechanical drives, ❖ Rigid – Gear drives
❖ Flexible – Belt drives, Chain drives, Rope drives
Gear drive Belt drive Chain drive Rope drive
⑰
Advantages of flexible drives over rigid drives
❖ Can transmit power over a comparatively long distance
❖ Absorbs shock loads and damps vibrations
❖ Flexibility of the location of driving and driven shaft
❖ Low initial and maintenance cost (manufacturing and material cost is high in Gear drives)
⑰
Disadvantages of flexible drives
❖ Occupy more space
❖ Velocity ratio is relatively small ( High velocity ratio ----> High torque conversion ratio)
❖ In general, velocity ratio is not constant. (Can define velocity range)
, Introduction to Belt Drives
.
torque
d small
➢ Consist of driving pulley, driven pulley and an endless belt e h ig h rpm an into wheel.
produc t use directly igh torque.
ngine o h
C o mb usion E torque can n w rpm and
al w lo
Intern h rpm and lo is converts to
➢ Transmit power by means of friction ig
This h Gear Box, th
g
By usin
➢ Mostly used for speed reduction
- Smaller pulley to highspeed shaft and larger pulley to low speed shaft
- Speed reduction caused in increasing the torques
➢ Selection of a belt drive depend on,
H
- Speed of the driving and driven shaft
- Amount of Power to be transmitted
- Speed reduction ratio
S
- Center distance between the shafts
- Positive drive requirements
- Shaft layout
- Space available & Service condition
W
Advantages & Disadvantages of Belt Drives
➢ Advantages
❖ Can transmit power over considerable distance between the axes of driving and driven shafts.
❖ The operation of belt drive is smooth and silent.
❖ Can transmit only a definite load - protecting the parts of the drive against overload.
❖ Ability to absorb the shocks and damp vibration.
❖ Simple design and low initial cost
➢ Disadvantages
❖ Due to large dimensions, occupy more space.
❖ Velocity ratio is not constant due to belt slip.
❖ Imposed heavy load on shafts and bearings.
❖ Considerable loss of power due to low efficiency.
❖ Comparatively short service life.
Types of belts & applications
➢Depend on the shape of the belt, ❖Flat belt
❖V-belt
❖Circular belt/ round belt Flat Belt
❖Timing belt.
❖Ribbed belt
😱
Timing Belt
Round Belt Ribbed Belt
V Belt
➢ Introduction
❖ Introduction to belt drives
❖ Advantages & disadvantages
❖ Types of belts & applications
❖ Belt configurations
❖ Materials used for belts
➢Velocity Ratio of belt drives
➢Slip of belt
H
➢Geometry of belts
❖ Open belt configuration
❖ Crossed belt configuration
S
➢Analysis of belt tensions
➢Power transmission in belt drives
Mechanicl Drives
W
⑰
Types of mechanical drives, ❖ Rigid – Gear drives
❖ Flexible – Belt drives, Chain drives, Rope drives
Gear drive Belt drive Chain drive Rope drive
⑰
Advantages of flexible drives over rigid drives
❖ Can transmit power over a comparatively long distance
❖ Absorbs shock loads and damps vibrations
❖ Flexibility of the location of driving and driven shaft
❖ Low initial and maintenance cost (manufacturing and material cost is high in Gear drives)
⑰
Disadvantages of flexible drives
❖ Occupy more space
❖ Velocity ratio is relatively small ( High velocity ratio ----> High torque conversion ratio)
❖ In general, velocity ratio is not constant. (Can define velocity range)
, Introduction to Belt Drives
.
torque
d small
➢ Consist of driving pulley, driven pulley and an endless belt e h ig h rpm an into wheel.
produc t use directly igh torque.
ngine o h
C o mb usion E torque can n w rpm and
al w lo
Intern h rpm and lo is converts to
➢ Transmit power by means of friction ig
This h Gear Box, th
g
By usin
➢ Mostly used for speed reduction
- Smaller pulley to highspeed shaft and larger pulley to low speed shaft
- Speed reduction caused in increasing the torques
➢ Selection of a belt drive depend on,
H
- Speed of the driving and driven shaft
- Amount of Power to be transmitted
- Speed reduction ratio
S
- Center distance between the shafts
- Positive drive requirements
- Shaft layout
- Space available & Service condition
W
Advantages & Disadvantages of Belt Drives
➢ Advantages
❖ Can transmit power over considerable distance between the axes of driving and driven shafts.
❖ The operation of belt drive is smooth and silent.
❖ Can transmit only a definite load - protecting the parts of the drive against overload.
❖ Ability to absorb the shocks and damp vibration.
❖ Simple design and low initial cost
➢ Disadvantages
❖ Due to large dimensions, occupy more space.
❖ Velocity ratio is not constant due to belt slip.
❖ Imposed heavy load on shafts and bearings.
❖ Considerable loss of power due to low efficiency.
❖ Comparatively short service life.
Types of belts & applications
➢Depend on the shape of the belt, ❖Flat belt
❖V-belt
❖Circular belt/ round belt Flat Belt
❖Timing belt.
❖Ribbed belt
😱
Timing Belt
Round Belt Ribbed Belt
V Belt
