Q1: What is a Gear?
Ans: A gear is a machine element having teeth which is used to transmit motion and power from one shaft to another.
Q2: What is a Spur Gear?
Ans: A spur gear is a type of gear having straight teeth parallel to the axis. It is used to transmit motion between parallel shafts.
Q3: Name some Gear Terminologies.
Ans: Some important gear terminologies are:
- ➔ Pitch Circle
- ➔ Pitch Diameter
- ➔ Addendum
- ➔ Dedendum
- ➔ Module
- ➔ Circular Pitch
- ➔ Tooth Thickness
Q4: What is Dendum?
Ans: Dendum (Dedendum) is the distance from the pitch circle to the root of the gear tooth.
Formula:
Dedendum = 1.166M
Q5: What is Addendum? Write the formula.
Ans: Addendum is the distance from the pitch circle to the top of the gear tooth.
Formula:
Addendum = 1M
Q6: What is Tooth Thickness of gear? Write a formula.
Ans: Tooth thickness is the width of a gear tooth measured along the pitch circle.
Formula:
Tooth Thickness = 1.57M
Q7: What is a Tooth Gap?
Ans: Tooth gap is the space between two adjacent gear teeth.
Q8: What is a Pitch Diameter? Write the formula.
Ans: Pitch diameter is the diameter of the pitch circle of the gear.
Formula:
Pitch Diameter = M × Z
Q9: What is a Root Diameter? Write the formula.
Ans: Root diameter is the diameter of the circle passing through the bottom of gear teeth.
Formula:
Root Diameter = D - 2 × Dedendum
Q10: What is a Module? Write the formula.
Ans: Module is the ratio of pitch diameter to number of teeth.
Formula:
M = D / Z
Q11: What is Clearance?
Ans: Clearance is the distance between the top of one gear tooth and the bottom of the mating tooth space.
Formula:
Clearance = 0.166M
Q12: What is Gear Blank?
Ans: Gear blank is the raw cylindrical piece of metal on which gear teeth are cut.
Q13: What is a Rack?
Ans: A rack is a straight gear having teeth cut on a flat surface. It is used to convert rotary motion into linear motion.
Q14: Write the calculation for Spur Gear.
Ans: Basic calculations for spur gear:
- ➔ Pitch Diameter = M × Z
- ➔ Addendum = M
- ➔ Dedendum = 1.166M
- ➔ Clearance = 0.166M
- ➔ Outside Diameter = (Z + 2)M
- ➔ Tooth Thickness = 1.57M
- ➔ Circular Pitch = π × M
Q15: A spur gear of 20 teeth is cut with 02 Module on a milling machine. Calculate Depth of Teeth, Cutter #, Outside diameter and Indexing.
Ans: Given:
Z = 20, M = 2
Step 1: Depth of Teeth
Depth = 2.166M
= 2.166 × 2 = 4.332 mm
Step 2: Cutter Number
For 20 teeth → Cutter No. = 6
Step 3: Outside Diameter
OD = (Z + 2)M
= (20 + 2) × 2 = 44 mm
Step 4: Indexing
Indexing = 40 / Z
= 40 / 20 = 2 turns
Q16: What will be the circular pitch of 02 Module?
Ans: Formula:
Circular Pitch = π × M
= 3.14 × 2
= 6.28 mm
Q17: What will be the circular pitch of the 1.5 Module?
Ans: Formula:
Circular Pitch = π × M
= 3.14 × 1.5
= 4.71 mm
Q18: What will be the pitch diameter of 02 Module of 80 teeth?
Ans: Formula:
D = M × Z
= 2 × 80
= 160 mm
Q19: What will be the pitch diameter of gear of the 1.5 Module of 60 teeth?
Ans: Formula:
D = M × Z
= 1.5 × 60
= 90 mm
Q20: What will be the pitch diameter of spur gear of 01 Module of 100 teeth?
Ans: Formula:
D = M × Z
= 1 × 100
= 100 mm
