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CYCLE-1

Experiment No.

Date:

Epicyclic Gear TrainAim of experiment:- To determine the velocity ratio of the epicyclic gear train.

Apparatus Required:-

Epicyclic gear train mechanism

Theory:-

Sometimes, two or more gears are made to mesh with each other to transmit power from

one shaft to another. Such a combination is called gear tr ain or train of toothed wheels.

The nature of the train used depends upon the velocity ratio required and the relative

position of the axes of shafts. A gear train may consist of spur, bevel or spiral gears.

Types of Gear Trains:

Following are the different types of gear trains, depending upon the arrangement of

wheels:

1. Simple gear train,

2. Compound gear train,

3. Reverted gear train, and

4. Epicyclic gear train.

In the first three types of gear trains, the axes of the shafts over which the gears are

mounted are fixed relative to each other. But in case of epicyclic gear trains, the axes of

the shafts on which the gears are mounted may move relative to a fixed axis.

.

Figure 1. An epicyclic gear train and its associated terminology

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Velocity Ratio Of Epicyclic gear train:

Table of motions.

Revolu tions of elements

Step No. Conditions of motion

Arm

CGear A Gear B

1.

Arm f ixed-gear A r otates through + 1 r evolution i .e.

1 rev. anticlockwise 0 +1

-TA/TB

2.

Arm f ixed-gear A rotates through

+ x revolutions0 +x

x*-TA/TB

3. Add + y r evolutions to all elements + y + y + y

4. Total motion + y +x+y

Y- xTA/TB

PROCEDURE

Gearing Arrangement

(i) Identify each of the components in the gear system which consists of a sun gear, planet gears, carrier armand

the ring or annulus gear.

(ii) Make a sketch of the gear arrangement, identifying each of the gears in the arrangement.

(iii) Count the numbers of teeth on each gear and mark on the sketch.

Simple Gear Train(iv) Fix the carrier arm so that it doesnt rotate. With the sun being the input shaft and the annulus the output

shaft, experimentally determine the velocity ratio between the input and output shafts.

(v) Compare the experimental velocity ratio to that obtained analytically.

Annulus Gear Fixed(vi) Release the carrier arm and fix the annulus gear. With the sun being the input shaft and the carrier arm the

output shaft, experimentally determine the velocity ratio between the input and output shafts.

(vii) Compare the experimental velocity ratio to that obtained by the analytical tabular method.

Sun Gear Fixed(viii) Release the annulus gear and fix the sun gear. With the carrier arm being the input shaft and the annulus

gear the output shaft, experimentally determine the velocity ratio between the input and output shafts.

(ix) Compare the experimental velocity ratio to that obtained by the analytical tabular method.

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Calculation Table:

Model Calculation:

Result :

The Velocity ratio of the gears are calculated properly as per different revolution.

Table of motions.

Revolutions of elements

Step No. Conditions of motion

Arm

CGear A Gear B

1.

Arm f ixed-gear A rotates through + 1 revolution

i.e. 1 rev. anticlockwise

2.

Arm f ixed-gear A rotates through

+ x revolutions3. Add + y r evolutions to all elements

4. Total motion