MECHANICAL DESIGN - t U
Transcript of MECHANICAL DESIGN - t U
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
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 7
Alignment
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 8
Flexible couplings
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
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
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 17
Bolt dimension
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 18
Calculation
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
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
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 22
Keyway broaching
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
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
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 29
Other shaft joining mechanisms
Spline
ME TUMechanical Engineering DepartmentFaculty of Engineering, Thammasat University
ME311 Module 6 : Couplings and Keys 30
Axial positioning mechanisms
Retaining rings
Radial assembly rings
Axial assembly
rings