http://www.wikipedia.org
Gears in farm equipment.
Gears in farm equipment.
Gears and the Gear Pump
Gears
Gears are toothed wheels that rotate to
transmit force to other gears. They are aligned so that when one gear turns,
its teeth move the teeth of other gears, causing them to rotate.
Connecting gears always spin in
opposite directions. So if one gear spun clockwise, all of the gears connected
to it would have spin counter-clockwise, and all of the gears connected to that
one would spin clockwise.
Gears can increase force or decrease
distance (increase speed), just like levers and hydraulics. This is measured
with agear ratio, and a velocity ratio. If one gear in a
pair is bigger and has more teeth than another gear, it revolves more slowly.
Gear ratio is:
(Teeth on effort gear)/(Teeth on load
gear)
Example: You are turning a gear with 20
teeth around. The gear is connected to another gear with 10 teeth. The gear
ratio is 20/10, which can be expressed as 1/0.5 or 1:0.5. The first number in
the gear ration is the gear effort is applied to. This means that the each time
the effort gear makes a rotation the load gear makes 2 rotations, because
1/0.5=2. You would have to apply twice as much force to the effort gear to make
the load gear turn, but it would turn twice as fast than if both gears were the
same size.
Now let's assume that the effort gear
with 20 teeth is connected to a gear with 40 teeth. 20/40 is the same as 1/2 or
1:2, so each time the the smaller effort gear would turn once, The load gear
would turn 0.5 times (since 1/2=0.5). Although you would have to turn the
effort gear twice as fast as the load gear, it would be twice as easy to turn.
The Gear Pump
One of the kinds of pumps that may be
in a backhoe to supply oil to the hydraulic systems is the gear pump. It uses
gears to pump oil. Another kind of pump you would find is the hydraulic
variable displacement pump, which is much more complex. Gear pumps are called fixed displacement pumps because they pump a fixed amount
of fluid for every revolution.
The gear pump consists of two gears in
a sealed container rotating in opposite directions. On one side of the pump is
an intake attached to an oil tank and on the other side a discharge that in the
case of the backhoe would lead to the hydraulic systems.
The actual operation of the pump is
very simple: one of the gears is rotated by the engine, which causes the other
gear to rotate as well. When the teeth of the gears separate on the intake side
of the pump, a vacuum is created that is filled with oil. The gears then carry
the oil to the discharge side of the pump.
http://www.wikipedia.org
The basic design of the gear pump.
The basic design of the gear pump.
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