gear metrology - me.iitb.ac.inramesh/courses/me338/metrology8.pdf · functions of a gear • power...
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Gear Metrology
ME 338: Manufacturing Processes II
Instructor: Ramesh Singh; Notes: Profs. Singh/Kurfess1
Gear
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh; Notes: Profs.
Singh/Kurfess
Functions of a Gear
• Power transmission
• Change rotational speed/torque
• Maintain constant speed ratio
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh; Notes: Profs.
Singh/Kurfess
Gear Box
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh; Notes: Profs.
Singh/Kurfess
Gear Kinematics
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh; Notes: Profs.
Singh/Kurfess
Line of Action
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh; Notes: Profs.
Singh/Kurfess
Involute Profile
• Formed by unwrapping a tangent chord from the base circle
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh
Definitions
• Diametral pitch, P = N/D
• Module M is reciprocal of P = D/N
• Circular pitch = πM (arc on pitch circle from flank of one tooth to other tooth)
• Base pitch = Pb = πM cosφ• Base pitch = Pb = πM cosφ
• Addendum = M
• Dedendum = 1.157 M/1.250M/1.400M
• Clearance = Dedendum-addendum
• M, N, φ are required for characterization
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh
Gear Measurement
• General Tests
• Measurement of individual elements
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh
Dual flank test
Test Results
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh
Gear Tooth Measurement-Gear Tooth Vernier
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh
W=NMsin(90/N)
Base Tangent Method
• Single tooth measurement has errors so multiple
teeth can be measured at one go
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh
Base Tangent Method
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh
++−=
N
S
NNMW
22tancos
ππφφφ
Where N=No. of teeth; M=Module; φ=Pressure angle;
S= No. of tooth spaces in W
Pitch Measurement
Gage A is constant
due to gear indexing
Any change in gage B shows
That there are errors
ME 338: Manufacturing Processes IIInstructor: Ramesh Singh
That there are errors
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