couplings and flywheels - mercer...

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

Shigley’s Mechanical Engineering Design

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

Hypothetical Flywheel Case: Work & Energy

Shigley’s Mechanical Engineering Design

Fig. 16–27

Kinetic Energy

Shigley’s Mechanical Engineering Design

Engine Torque for One Cylinder Cycle

Shigley’s Mechanical Engineering Design Fig. 16–28

Punch-Press Torque Demand

Shigley’s Mechanical Engineering Design

Fig. 16–29

Coefficient of Speed Fluctuation, Cs

Shigley’s Mechanical Engineering Design

Energy Change

Shigley’s Mechanical Engineering Design

Cs=Coefficient of Speed Fluctuation

More Basic Flywheel Equations

𝐼 = 12𝑀𝑟

2 Mass Moment of Inertia for a solid disk about central axis

Energy change in/out ∆𝐸 = 12𝐼 𝜔

2𝑚𝑎𝑥 − 𝜔2

𝑚𝑖𝑛

Punch-Press Analysis

Shigley’s Mechanical Engineering Design