2. Gear Box
Gearbox often referred as transmission is a
unit that uses gears and gear trains to
provide speed and torque conversions from a
rotating power source to another device.
Gearboxes are employed to convert input from
a high speed power sources to low speed(Eg.
Lift, Cranes and Crushing Machine) or into
a many of speeds(Lathe, Milling Machine and
Automobiles).
3. A gearbox that converts a high speed input
into a single output it is called a single
stage gearbox. It usually has two gears and
shafts.
A gearbox that converts a high speed input
into a number of different speed output it is
called a multi-speed gear box.
Multi speed gear box has more than two gears
and shafts. A multi speed gearbox reduces the
speed in different stages.
4. Preferred Numbers or Preferred
Step Ratio
In order to get a series of output speeds from a
gearbox, geometric progression is used.
By using geometric progression the speed is
reduced uniformly in different stages.
Geometric progression, also known as a
geometric sequence, is a sequence of
numbers where each term after the first is
found by multiplying the previous one by a
fixed, non-zero number called the common
ratio (called as progression ratio or step ratio
in gear box design).
5. Step Ratio
In gearbox design a set of preferred step ratio
or preferred numbers is used to obtain the
series of output speed of gearbox.
The preferred step ratio is mentioned as basic
series named as R5, R10,R20,R40 and R80.
Each basic series has a specific step ratio.
7. A kinematic layout is a pictorial representation of a gearbox, describing
the arrangement of gears. It provides information like number of
stages, number of shafts used, number of gear pairs and its
arrangement. The following diagram is the kinematic arrangement of a
12 speed gear box.
Kinematic Layout
8. A ray diagram is a representation of structural formula. It
provides information such as speed in each stage, the
transmission ratio in each stage, The total number of
speeds and its values. The following diagram is a ray
diagram of a 12 speed gearbox.
