A spur gear, with a pitch-circle diameter of 168 mm and 42 teeth, is needed for a gearbox - NSC Mechanical Technology Fitting and Machining - Question 6 - 2022 - Paper 1
Question 6
A spur gear, with a pitch-circle diameter of 168 mm and 42 teeth, is needed for a gearbox. Calculate the following:
6.1.1 Module
6.1.2 Circular pitch
6.1.3 Outsid... show full transcript
Worked Solution & Example Answer:A spur gear, with a pitch-circle diameter of 168 mm and 42 teeth, is needed for a gearbox - NSC Mechanical Technology Fitting and Machining - Question 6 - 2022 - Paper 1
Step 1
6.1.1 Module
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Answer
To determine the module (m) of the spur gear, use the formula:
m=TPCD
where:
PCD is the pitch-circle diameter (168 mm)
T is the number of teeth (42)
Substituting the values:
m=42168=4
Thus, the module of the gear is 4 mm.
Step 2
6.1.2 Circular pitch
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Answer
The circular pitch (CP) can be calculated using the formula:
CP=m×π
Substituting the previously calculated module:
CP=4×π≈12.57 mm
Therefore, the circular pitch is approximately 12.57 mm.
Step 3
6.1.3 Outside diameter
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Answer
The outside diameter (OD) can be calculated using:
OD=m×(T+2)
Substituting the values:
OD=4×(42+2)=4×44=176 mm
Hence, the outside diameter of the gear is 176 mm.
