4. POWER TRANSMISSION SYSTEMS DESIGN AND APPLICATIONS OF INDUSTRIAL ROBOTS SABARIGIRIVASAN.R ISBN 978-81-908268-0-8 4. PO W ER TRANSM ISSIO N SYSTEM S D E S IG N A N D A P P L IC A T IO N S O F IN D U STR IA L R OBOTS SA B A R IG IR IVA SA N .R IS B N 978-81-908268-0-8
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4. POWER TRANSMISSIONSYSTEMS
DESIGN AND APPLICATIONS OF INDUSTRIAL ROBOTSSABARIGIRIVASAN.RISBN 978-81-908268-0-8
4. POWER TRANSMISSIONSYSTEMS
DESIGN AND APPLICATIONS OF INDUSTRIAL ROBOTSSABARIGIRIVASAN.RISBN 978-81-908268-0-8
Power Transmission Systems1. Power transmission systems are used to
transmit motion from the prime mover to the end equipment.
2. They are also used for motion conversion like rotary to linear and vice versa.
3. Power transmission systems widely used in robotics are
a) Gearsb) Beltsc) Chainsd) Shafts
2
Gears1. Gears are devices that have teeth cut on them
at regular intervals for transmitting motion without slipping.
2. Gears are used for transmitting motion when distance between two shafts are small.
3. Gears have higher transmission efficiency and higher load carrying capacity.
4. Cast iron and high strength alloy steels are used for making gears. Nylon is also used.
3
Classification of Gears1. Based on arrangement of teeth for engaging
with another geara) External gearsb) Internal gears
2. Based on teeth designa) Spur gearsb) Helical gearsc) Bevel gearsd) Worm gearse) Racks
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External Gear
5
Animation
Internal Gear
6
Animation
Spur GearSpur Gear
D E S I G N A N D A P P L I C A T I O N S O F I N D U S T R I A L R O B O T SS A B A R I G I R I V A S A N . R
Straight teeth
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Helical GearHelical Gear
D E S I G N A N D A P P L I C A T I O N S O F I N D U S T R I A L R O B O T SS A B A R I G I R I V A S A N . R
Inclined teeth
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Bevel Gear
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Types of Bevel Gear
10
Worm Gear
Animation11
Rack and Pinion
Animation12
Belts1. Belts are used when distance between two
shafts are very large.2. Belts run over friction pulleys mounted on
ends of both the shafts.3. Rubber belts woven with nylon fibres are
most widely used.4. Woven nylon fibres provide adequate
mechanical strength to the belt.
13
Types of Belts
Different belt profiles are1. Flat belts2. V – belts3. Cog belts
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Belt Profiles
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Flat Belt Drive
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Flat Belt Drive
Animation17
Cog Belt Drive
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Cog Belt Drive
Animation19
Chains 1. Chains are metal structures made up of
many links joined serially to form a closed loop.
2. They are used for transmitting higher load over long distances without slipping.
3. Sprockets are fitted on both the shafts for engaging the chain.
4. Bush roller chain is widely used.
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Chain and Sprocket
21
Structure of Roller Chain
22
Shafts 1. Transmission shafts are used to transmit
motion from one end to the other.2. Solid and hollow cylindrical shafts are
widely used.3. Transmission shafts should have high
strength and high wear resistance.4. They should be capable of resisting the twist
to transmit higher torque.5. Couplings and Bearings are used to connect
and support the shafts.23
Couplings1. Couplings are used to connect two different
shafts.2. Couplings are used to connect prime mover
to the actuator and other intermediate transmission systems.
3. A coupling should transmit power without loss.
4. They should be easily assembled and disassembled.
24
Types of couplingsCouplings are of two types1. Rigid coupling
a) Flange couplingb) Split muff couplingc) Sleeve coupling
1. Bearings are used to provide frictionless free movement to the joints in the robot.
2. Bearings are also used to support the transmission shafts.
3. They helps to reduce wear between moving parts.
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Classification of Bearings1. Based on direction of loading
a) Radial bearingsb) Thrust bearings
2. Based on contact conditiona) Sliding contact bearings
• Journal bearing
b) Rolling contact bearings• Ball bearings• Roller bearings
35
Classification of Bearings Based onDirection of Loading
36
Ball Bearings1. Ball bearings have hardened steel balls in
between the stationary and moving members.2. Balls are held in place by a ball cage.3. Types of Ball bearings
a) Single row radial ball bearingb) Double row radial ball bearingc) Single direction thrust bearingd) Double direction thrust bearinge) Double direction angular contact thrust bearing
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Ball Bearing
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Types of Ball Bearings
39
Roller Bearings1. Roller bearings have hardened steel rollers in
between the stationary and moving members.2. Rollers are held in place by a cage.3. Types of Roller bearings