Introduction to Lego Robotics

1
Introduction to Lego Robotics 

• Jan 12th, 2008

2

• Lesson 4
• Gear (part 1)
• Continue lab work to build the wheel mechanism

Introduction to Lego Robotics
2
3
Spur Gear
Circumference 2 x Pi x Radius Circumference
Tooth Size x Tooth Count Size x Count 2 x Pi x
Radius Size 2 x Pi x Radius / Count (16
teeth) 2 x Pi x 1 / 16 Pi / 8 studs
0.392 studs or 3.14 mm

• 8 16 24 40

• Gears are normally referred to by their type and
  the number of teeth.
• For example, an 8 tooth spur gear.
• Also, a 40 tooth spur gear can be referred to as
  a 40t gear.
• All the different sized spur gears have the same
  sized teeth. Having the same sized teeth allows
  the gears to mesh properly.
• For gears with number of teeth is 8, its radius
  (studs) is 0.5. Similarly, (16 teeth, 1 stud
  radius), ( 24 teeth, 1.5 studs radius), (40
  teeth, 2.5 studs radius)

4
Gear Ratio
Output gear, 24 teeth
Input gear, 8 teeth
31 Gear Ratio

• Gear Ratio number of Teeth Output Gear / number
  of Teeth Input Gear
• Gear Ratio 24 8 3 1
• Torque Force x Radius
• Torque of output Gear Torque of input Gear
  Gear Ratio