Gears, Sprockets, and Pulleys

  • These three power train ratios elements transfer energy though rotary motion
  • Change the speed of rotation
  • Change the direction of rotation
  • Change the amount of torque available to do work
  • If one gear is turning clockwise, the other one will turn counterclockwise
  • When two gears touch each other, they change direction
  • Problem:
    • One motor gears, two axles, and the rotation of both of them both needs to be anti-clockwise
  • Gears
    • A gear train is a mechanism used for transmitting rotary motion and torque through interlocking teeth
    • A gear train is made when two or more gears are meshed
    • Driver gear causes motion
    • Motion is transferred to the driver gear
    • When a gear misses a tooth and it skips a gear, it is called XXXX?
  • Gears
    • Mating gears always turn in opposite directions
    • An idler gear allows the driver and the driven gears to rotate in the same direction
    • Mating gears always have the same size teeth (diametric teeth)
    • The rpm of the larger gear is always slower than the rpm of the smaller gear
    • Gears locked together on the same shaft will always turn in the same direction and at the same rpm
  • Gear Ratios
    • Variables to know:
    • n = the number of teeth
    • d = diameter
    • w = angular velocity (speed)
    • t = torque
      • subscripts in and out are used to distinguish between gears
    • Equations to know
      • GR = Gear Ratio
      • GR/1 = nout/nin = dout/din/win/wout=tout/tin
      • What is the gear ratio between gear A and gear B?
      • A has 120T and B has 12 T so it is .6/1
      • The number of the gear ratios present in a system is one less than the number of gears present in that system
      • Idler gears do not affect the gear ratios. Therefore, the gear ratio would be one because A has 20T and D has 20T
  • Pulley and Belt Systems
    • dout/din = win/wout = tout/tin
    • d = diameter
    • w is the angular velocity or speed
    • t = torque
    • they go in the same direction
    • Choices are moment (beam producing a force), angular velocity (when turning), or regular velocity (velocity in a straight line) and torque force (ft-lbs or N)
  • Sprocket and Chain Systems
    • nout/nin = dout/din = win/wout = tout/tin
    • n is the number of teeth
    • d is diameter
    • w is the angular velocity or speed
    • t is torque

QR Code
QR Code gears_sprockets_and_pulleys (generated for current page)