Chapter 6 Design of Keys, Splines and Pins

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Chapter 6 Design of Keys, Splines and Pins

• Key terms
• Keys
• Splines
• Keyway, keyseat
• Hub
• Crush
• Pin

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6.1 Key Joints

• 1. Basic Concept
• A key is a fastening
• inserted into the keyway
• of two mating parts,
• it is used to transmit
• torque from a shaft to
• a hub or vice versa.

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2. Types of Keys

• Straight keys
• Woodruff keys
• Taper keys
• Splines

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3. Straight Key Joints

• 1) Principles

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2) Types

• a. Plain flat keys ???? (fixed joints)

C Key with one square and one rounded end
B Key with square ends
A Key with rounded ends
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b. guided keys (sliding joints)
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c. feather key joints (sliding joints)
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4.Woodruff Key Joints
Greater depth of the key seat in the shaft.
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5. Taper Key Joints
Gib-head taper key
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Tangent Double-taper Key Joints
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6. Strength Calculation of Straight Key Joints

• 1)Failure Modes crush, wear, snip

Ttorque
ddiameter of shaft
hthickness of the key
lworking length of the key
?pallowable crush stress
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• 3) Steps for Selecting Straight Keys
• a. According to the diameter of shaft, get
  section size
• b ? h
• b. Select proper key length L in key length
  series
• c. Check the Strength Calculation (if necessary)

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4) Double-Keys Arrangement
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6.2 Splines Joints

• Splines can be dealt as multiple keys which are
  integral with the shaft.

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Advantages 1) Greater carrying capacity 2)
Greater fatigue strength of a spline shaft 3)
More accurately centered and guided.

• Disadvantages
• Requirements for special equipments and tools,
  which increase the manufacturing costs.

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6.3 Pin Joints
Pin for joining
Cylindrical pin
Taper pin
safety pin
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Key Standards
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The endThanks!