GEAR TRAINS

GROUP MEMBERS

09• T

ouseef Haidar

18

• Arham saleem

17• M

uhammad Asghar

CONTENTSGear

Gear trains

Types of gear train

GEARS Gears are basically power transmation

machine equipment . you can transmit power from one element of the machine to the other element of the machine by using the gears

GEAR TRAINS Two or more gears are made to mesh

with each other to transmit the power from one shaft to another shaft .such as the combination is called Gear train /toothed wheels.

USED The nature of the train used depend

opon the velocity ratio required and relative position of the axes of the shaft.

A gear train may be consist of spur bevel and spiral gear.

TYPES OF GEAR TRAIN The different types of gear train

depending upon the arrangment on the wheel.

there are four types of gear train.

Simple gear train compound gear trai Reverted gear train Epicylic gear train

In the first three types of the gear train. The axes of the shafts over which the gears are mounted are fixed relative to the each other. But in the case of the epicyclic gear train the axes of the shafts on which the gear are mounted may move relative to a fixed axis .

SIMPLE GEAR TRAIN There is only one gear on each shaft.it

is called the simple gear train. when the distance between the two

shafts is small the two gears1 and 2 are made to mesh with each other to transmit motion from one shaft to the other.since the gear 1 drives the gear 2.therefore gear 1 is call driver. the gear two is called driven /follower. It may be noted that the motion of the driven gear is opposite to the motion of driving gear.

v

AB

GEAR 'A' GEAR 'B'(Idler gear)

IDLER GEAR The only function of the idler gear is to

change the direction of rotation. It has no affect on the gear ratio. The teeth on the gears must all be the same size

use 1) to connect gears where a large

centre distance is required 2) To obtain the desired direction of

Motion of the driven gears (clockwise or anti clockwise)

Speed ratio the speed ratio of the gear train is the ratio

of speed of the driver to the speed of the driven and ratio of speed any pair of the gears in mesh is the inverse of their number of the teeth.

Train value it may be noted that ratio of the speed of

the driver or follower to the speed of the speed of the driver is known as train value of the gear train

COMPOUND GEAR TRAIN when there are more than one gear on a

shaft.it is called compound gear . these gears are useful in bridging over

the space between the driver and driven.

GEAR 'A'

GEAR 'B'

GEAR 'C'

GEAR 'D'

Compound Gears

A

C

BD

Output

Input

Compound gears are simply a chain of simple gear trains with the input of the second being the output of the first. A chain of two pairs is shown below. Gear B is the output of the first pair and gear C is the input of the second pair. Gears B and C are locked to the same shaft and revolve at the same speed.

In the compound gear train.the gear A is the driving gear mounted on shaft A,gear 1, gear 2and 3 are compound gear which are mounted on shaft on shaft B.the gears 4 and 5 are also compound gear which are mounted on shaft C and the gear 6 is the driver gear mounted on shaft D.

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