Post on 18-Dec-2021
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311MECHANICAL DESIGN
Module 6Couplings and Keys
Dulyachot CholaseukMechanical Engineering Department
Thammasat University
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 2
Contents
1. Coupling design2. Key design
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 3
Coupling design1Function: connect two shafts
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 4
Rigid coupling
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 5
Alignment problem
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 6
Alignment problem
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ME311 Module 6 : Couplings and Keys 7
Alignment
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ME311 Module 6 : Couplings and Keys 8
Flexible couplings
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ME311 Module 6 : Couplings and Keys 9
Universal joints for extreme misalignment
Universal joints cause speed fluctuation.
Universal joints have axial movement
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 10
Universal joints Speed fluctuation
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 11
CV joints for extreme misalignment and sliding
Rzeppa CV Tripod CV
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 12
Tripod CV joints
Tripod CV
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 13
Rzeppa CV joints
Rzeppa CV
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 14
Flange couplings
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 15
Sizing of rigid couplings
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 16
Standard dimension
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ME311 Module 6 : Couplings and Keys 17
Bolt dimension
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ME311 Module 6 : Couplings and Keys 18
Calculation
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ME311 Module 6 : Couplings and Keys 19
Safety factor
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 20
Key design2Function: connect hub to shaft by positive contact
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 21
Types of keys
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ME311 Module 6 : Couplings and Keys 22
Keyway broaching
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ME311 Module 6 : Couplings and Keys 23
Keyway milling
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 24
Average stresses in key
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 25
Question
Theoretically keys should be square
(h = w) but in practice h < w for larger
shaft. Why?
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 26
Design procedure
Sizing the shaft and the hub
Select standard key size from the table
Determine the length from
2 s
y
N FlS h
=
If the key is longer than the standard hub
hub shaft1.2 2l d≈ −
then the use of multiple keys may be a solution.
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 27
Standard key size
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 28
Other shaft joining mechanisms
Tapered pin
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ME311 Module 6 : Couplings and Keys 29
Other shaft joining mechanisms
Spline
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ME311 Module 6 : Couplings and Keys 30
Axial positioning mechanisms
Retaining rings
Radial assembly rings
Axial assembly
rings