Rotary. Pulley Systems. Pulley Systems use a belt to transmit motion and force from the driver shaft...
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Transcript of Rotary. Pulley Systems. Pulley Systems use a belt to transmit motion and force from the driver shaft...
Rotary. Pulley Systems.
Pulley Systems use a belt to transmit motion and force from the driver shaft to the driven shaft.
Speed changes are made by using different size pulleys on the driver and driven shafts.
Speed changes
By comparing the size of the two pulleys you can calculate the velocity ratio of the system
Calculation
d1 d2
1 2
n1
n2
Pulleys formula:
n1 . d1 = n2 . d2 n1: pulley 1 speed
d1: pulley 1 diameter
n2: pulley 2 speed
d2: pulley 2 diameter
Gears
Gears are toothed wheels, fixed to the driver and driven shafts, which mesh together. The gears have a whole number of teeth.
Gear train
Speed changes are made by using different number of teeth on the driver and driven shafts.
Speed changes
You can calculate the velocity ratio of the system
Calculation
Gears formula:
n1 . Z1 = n2 . Z2
n1: gear 1 speed
Z1: gear 1 teeth
n2: gear 2 speed
Z2: gear 2 teeth
Chain and Sprocket systems
Chain and sprocket systems use a chain to transmit rotary motion from the driver to the driven shaft. Sprocket is the name of the gear when it use a chain.
The mechanism of the bicycle is a typical example
Chain and Sprocket systems
You can use the formula of the gears for this mechanism. It's the same.
n1 . Z1 = n2 . Z2
n1: sprocket 1 speed
Z1: sprocket 1 teeth
n2: sprocket 2 speed
Z2: sprocket 2 teeth
Worm gear
Another way of making large speed reductions is to use a worm gear.You can think of the worm as if it were a gear with 1 tooth.
Worm gear. Watch outWatch out
You can use the formula of the gears for this mechanism. It's the same.
n1 . 1 = n2 . Z2
n1: screw 1 speed
n2: gear 2 speed
Z2: gear 2 teeth
Rack and Pinion Systems.
Rack and pinion systems involve changes between rotary and linear motion.