Lab2E1 Gear Train

7/24/2019 Lab2E1 Gear Train

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Lab Manual

FACULTY OF ENGINEERING & BUILT ENVIRONMENT

SUBJECT: EGE 3411 LABORATORY INVESTIGATIONS 2

EXPERIMENT 1: GEAR TRAIN

1.0 OBJECTIVE

i. To determine velocity ratio of simple gear drive

ii. To observe the directions of rotation of simple gear trains.

2.0 THEORY/INTROUCTION

A gear train is a set or system of gears to transfer a rotational torque from one part of a

mechanical system to another which used to increased speed, decreased speed and change the

direction of motion of shafts. Different-sied gears are often used in pairs for a mechanical

advantage, allowing the torque of the driving gear to produce a larger torque in the driven gear at

lower speed, or a smaller torque at higher speed.

!ear trains consist of"

i. Driving gears #driver$ % attached to the input shaft

ii. Driven gears #follower$ % attached to the output shaft

!!!. &dler gears #follower$ % interposed between the driving and driven gear in order to

maintain the direction of the output shaft the same as the input shaft to increase the

distance between the drive and driven gears.

'(amples of gear trains"

i. )imple gear train

ii. *ompound gear train

iii. 'picyclic gear train

iv. +everted gear train

The gear ratio is the relationship between the numbers of teeth on two gears that are meshed.

The gear ratio of a gear train is the number of teeth on the follower divided by the number of

teeth on the driver.


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!ear ratio number of teeth of driven gear number of teeth of driving gear

A simple gear train consists of two or more meshed gears, where the gear shafts are parallel

and there is only one gear on each shaft. igure / shows a simple gear train consisting of 0 gears.

igure /" )imple gear train with an idler gear

1otice also that the driver and follower gears now turn in the same direction. &n a simple gear

train, the total gear ratio is the product of the gear ratios between the pairs of meshed gears. &f the

gears are labeled A, 2, and * as shown in the figure below, then the gear ratio is given by"

Vr=

nA

nB

=

nB

nC

=

nA

nC

where"

3r velocity ratio

nA speed of gear A

n2 speed of gear 2

n* speed of gear *

1otice that the idler has no effect on the gear ratio.

3.0 APPARATUS

i. )imple gear train 4it which shown in igure 5

ii. A simple arrangement of two spur gears

iii. A simple arrangement of three spur gears

iv. )et of weights

B

GearPinion

Idler CA


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igure 5" )imple gear train 4it

4.0 PROCEURES

4.1 S!"#$%' G%() T)(!*

/. *hoose two spur gears and anchor it to the frame such that the teeth of the gear interloc4

each other.

5. The bigger gear is the driver while the smaller is the follower.

0. *ount and note the number of teeth for each gear. Then calculate the gear ratio for this

pair of gears.

6. Mar4 the teeth of both gears that are located beneath the pointer.

7. +otate the driver by / revolution and note the number of revolution that the follower gear

ma4es.

8. The fraction of a revolution that the follower ma4es can be calculated by ta4ing the ratio

of the teeth to the ratio of a complete revolution. &f the gear ratio has 05 teeth and the

number of teeth from the point to the mar4 teeth is /9 then the number of revolution that

the gear has made is calculated as follows"

i. 32teet h=1 revolution

ii. 10 teet h= 13210revolution


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:. Ta4e readings from / to 8 revolutions

;. +ecord your result in Table /.


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+.0 RESULTS

+.1 S!"#$%' G%() T)(!*

1umber of teeth for the driver

1umber of teeth for the follower

+atio of follower" driver teeth

Table / )peed of driver and follower of simplest gears train

)peed of

driver

)peed of follower

*omplete

revolution #a$

&ncomplete revolution Total revolution

#a$ > #b$1o. of

teeth

raction of

+ev #b$

rev rev 1o rev rev

/

5

0

6

78

Table 5 !ears rotation of simplest gears train

LoadDriver !ear +otation ollower !ear +otation +otation

+atioDirection +?M Direction +?M

+.2 S!"#$% G%() T)(!* 1

1umber of teeth for the driver 1umber of teeth for the last follower


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+atio of last follower" driver teeth

Table 0 )peed of driver and follower of simple gears train /

)peed of

driver

)peed of last follower

*omplete

revolution #a$

&ncomplete revolutionTotal revolution

#a$ > #b$1o. of

teeth

raction of

+ev #b$

rev rev 1o rev rev

/

5

06

7

8

Table 6 !ears rotation of simple gears train /



+.3 S!"#$% G%() T)(!* 2

1umber of teeth for the driver

1umber of teeth for the last follower

+atio of last follower" driver teeth

Table 7 )peed of driver and follower of simple gears train 5


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)peed of

driver

)peed of last follower

*omplete

revolution #a$

&ncomplete revolutionTotal revolution

#a$ > #b$1o. of

teeth

raction of

+ev #b$rev rev 1o rev rev

/

5

0

6

7

8

Table 8 !ears rotation of simple gears train 5



,.0 ISCUSSION

i. ?lot the graph of the speed of follower to the speed of the driver for the three cases.

ii. rom the graphs determine the average speed ratio by calculating the slope. Then

compare it with teeth ratio.

iii. @bserve this effect of the idler gears to the system.

-.0 CONCLUSION

i. rom the plotted graph, write down your observation and ma4e your conclusion.

ii. *omment on the accuracy of the e(periment and ways of improving it.

iii. &f a motor is used to drive a certain component of a machine and the motor has a speed of

0999 rpm suggests a gear arrangement so that the component will have a speed of 099

rpm.

Lab2E1 Gear Train

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