Sph4c Gears and Gear Trains

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Transcript of Sph4c Gears and Gear Trains

  • Gears and Gear Trains: Student Learning GoalThe student will be able to identify and describe, in quantitative and qualitative terms, the operation and applications of gears (C3.1).

  • Gears and Gear TrainsSPH4C

  • GearsGears are toothed wheels on axles and are therefore members of the lever family.The teeth prevent slippage.

  • PurposeGears are used to transfer or change rotational speed.Example:

    The load gear will turn at 1/3 of the rotational speed of the effort gear (driver).

  • Gear RatioThis ratio of the number of teeth of the effort gear to the number of teeth of the load gear is called the gear ratio.

  • Gear RatioThis ratio of the number of teeth of the effort gear to the number of teeth of the load gear is called the gear ratio which is equal to the IMA.

  • IMAWhy would one want to use gears with an IMA of less than 1?

  • IMAWhy would one want to use gears with an IMA of less than 1?

    The trade-off is that when you reduce speed, you increase torque.

  • ExampleWhat is the IMA of the following set of gears?

  • ExampleWhat is the IMA of the following set of gears?

    IMA = 4 (or the gear ratio = 4:1)

  • Gear TrainsTo create larger gear ratios, gears are often connected in gear trains, for example:Each gear turns at twice the speed of the one to its left, which means that the red gear turns at 2 x 2 x 2 = 8 times the speed of the blue gear.

  • Planetary Gear TrainsPlanetary gear trains allow the output shaft to be along the same axis as the input shaft:Such a gearing system would be used in a device such as an electric screwdriver.

  • More PracticeConstruction with Gears Lab Activity

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