Couplings and Flywheels

MAE 322

Couplings are divided into categories

• Rigid & Flexible

• Rigid couplings by virtue of their simple rugged design are generally able to transmit more power than flexible couplings of comparable size but this is not an Important advantage except in high horsepower applications.

Shaft Misalignment Compensation

• Angular and Lateral Misalignment are common and always present to some degree.

Flexible Couplings

Universal joint bellows & plain couplings

Shaft Couplings

Shigley’s Mechanical Engineering Design

Fig. 16–26

Flexible Couplings

Bellows coupling

Flywheels

• Energy Storage

– Punch Press

– Baseball pitching machine

• Smooth out fluctuating torque

– Pistons on crank shaft

Flywheels: Torque required to accelerate

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Sum of the moment (torque) along the axis= Inertia x angular acceleration.

Hypothetical Flywheel Case: Work & Energy

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Fig. 16–27

Kinetic Energy

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Engine Torque for One Cylinder Cycle

Shigley’s Mechanical Engineering Design Fig. 16–28

Punch-Press Torque Demand

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Fig. 16–29

Coefficient of Speed Fluctuation, Cs

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Energy Change

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Cs=Coefficient of Speed Fluctuation

More Basic Flywheel Equations

𝐼 = 12𝑀𝑟2 Mass Moment of Inertia for a solid disk

about central axis

Energy change in/out ∆𝐸 = 12𝐼 𝜔2𝑚𝑎𝑥 − 𝜔

2𝑚𝑖𝑛

Punch-Press Analysis

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