rotary motion

54
Rotary Motion A Pulley Mechanism uses rotary motion to transmit rotary motion between two parallel shafts.

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Rotary Motion. A Pulley Mechanism uses rotary motion to transmit rotary motion between two parallel shafts. Mechanisms using Rotary Motion. Pulley mechanisms can be used to increase or decrease rotary velocity. Velocity Ratio. Distance moved by Effort. Velocity Ratio = . - PowerPoint PPT Presentation

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Page 1: Rotary Motion

Rotary Motion

A Pulley Mechanism uses rotary motion to transmit rotary motion between two parallel shafts.

Page 2: Rotary Motion

Mechanisms using Rotary Motion

Page 3: Rotary Motion

Pulley mechanisms can be used to increase or decrease rotary velocity

Page 4: Rotary Motion

Velocity Ratio Velocity Ratio =

Distance moved by Effort

Distance moved by Load

Velocity Ratio =

Distance moved by the driver pulley

Distance moved by the driven pulley

Velocity Ratio = Diameter of Driven Pulley

Diameter of Driver Pulley

Page 5: Rotary Motion

Velocity Ratio

Pulley Shaft Rotary Velocities can be calculated using the following formula

rotary velocity of driven pulley x diameter of driven pulley =

rotary velocity of driver pulley x diameter of driver pulley

rotary velocity of driven pulley =

rotary velocity of driver pulley x diameter of driver pulley

diameter of driven pulley

Page 6: Rotary Motion

What is the rotary velocity of the driven pulley shaft?

rotary velocity of driven pulley =

rotary velocity of driver pulley x diameter of driver pulley

diameter of driven pulley

= 450 x 3090

revs/min

= 150 revs/min

Page 7: Rotary Motion

Pulleys and Belts

A section through a grooved pulley and

round belt

Vee pulley and section through a vee pulley and belt

Stepped cone pulleys provide a range of shaft speeds

Page 8: Rotary Motion

Flat belts and

pulleys

A section through a flat pulley and belt

Flat belt in use on a threshing

machine

Jockey pulley in use

Page 9: Rotary Motion

Chains and sprockets

Bicycle chain and sprockets

Graphical symbols

Page 10: Rotary Motion

Velocity Ratio = number of teeth on the driven

sprocket number of teeth on the driver sprocket

= 12

36

= 1 : 3

Page 11: Rotary Motion

Example

Page 12: Rotary Motion

Pulleys and Lifting Devices

The pulley

is a form of Class 1 lever

Page 13: Rotary Motion

Movable single pulley

Page 14: Rotary Motion

Pulleys

Velocity Ratio =

Distance moved by Effort

Distance moved by Load

Velocity Ratio = the number of rope sections that support the load

Page 15: Rotary Motion

Two Pulley System

Velocity Ratio =

Distance moved by

Effort

Distance moved by

Load

Velocity Ratio =

2x

x

Velocity Ratio = 2:1

Page 16: Rotary Motion

Four Pulley System

Velocity Ratio =

Distance moved by

Effort

Distance moved by

Load

Velocity Ratio =

4x

x

Velocity Ratio = 4:1

Page 17: Rotary Motion

Cams

Page 18: Rotary Motion

Cams

Page 19: Rotary Motion

Uses

Pear shaped cams are used in valve control mechanisms

Page 20: Rotary Motion

Cams used in a four

cylinder engine

Page 21: Rotary Motion

Cam motions

Page 22: Rotary Motion

Types of cam follower

Page 23: Rotary Motion

Types of cam follower

Page 24: Rotary Motion

Springs are used to keep the follower in contact with the cam

Page 25: Rotary Motion

Cam Profiles

Page 26: Rotary Motion

Displacement graph for a pear shaped cam

Page 27: Rotary Motion

Displacement Graphs

Page 28: Rotary Motion
Page 29: Rotary Motion

Bearings

Page 30: Rotary Motion

Thrust Bearings

Page 31: Rotary Motion

Bearings

Page 32: Rotary Motion

Bearings

• Bronze• Nylon• PTFE• Air• White metal• Cast Iron• Sintered

Page 33: Rotary Motion

Gears

Page 34: Rotary Motion

Gears

Gears are not only used to transmit motion. They are also used to transmit force.

Page 35: Rotary Motion

Gears

Mechanical Advantage =

Number of teeth on the driven gear

Number of teeth on the driver gear

Velocity Ratio = Gear Ratio =

Number of teeth on the driven gear

Number of teeth on the driver gear

Page 36: Rotary Motion

Gears

Page 37: Rotary Motion

Gears

Gear Ratio =Product of teeth on the driven gearsProduct of teeth on the driver gears

Page 38: Rotary Motion

Gears

Page 39: Rotary Motion

Gears

Page 40: Rotary Motion

Gears

Page 41: Rotary Motion

Gears

Page 42: Rotary Motion

Basic Gear Geometry

http://www.sdp-si.com/D190/PDF/D190T25.PDF

Page 43: Rotary Motion

The inclined plane

Page 44: Rotary Motion

The inclined plane

Page 45: Rotary Motion

The inclined plane

Effort required to pull trolley up slopeF = effort E

F = 1000 x sin

F = 1000 x 0.01F = 10N

E = 10N

sin = 1/100 = 0.01

M.A. = 1000/10 = 100

Follow link to see effects of steeper incline:http://lectureonline.cl.msu.edu/~mmp/applist/si/plane.htm

Page 46: Rotary Motion

The screw thread

Page 47: Rotary Motion

Screw thread terms

Page 48: Rotary Motion

Screw thread forms

Page 49: Rotary Motion

Screw thread forms

Page 50: Rotary Motion

Screw thread forms

Page 51: Rotary Motion

B.S. PD7308

Page 52: Rotary Motion

Newton’s Laws

• First Law– A body continues in its state of rest or uniform

motion in a straight line unless compelled by some external forces to change that state.

(sometimes know as the law of inertia)

Page 53: Rotary Motion

Newton’s Laws

• Second Law– Rate of change of momentum is proportional to

the applied force and takes place in the direction in which the force acts.

(Continued force means continued acceleration)

Page 54: Rotary Motion

Newton’s Laws

• Third Law– To every action there is an equal and opposite

reaction