1. Sunil sharma
suraj karn prakash
susheel pal
t.aslam
d.thamotharan
Submitted by:
PrinciplesOfSelfAligning And
MethodsOfIncreasingRangeOf Regulation.
Department of manufacturing engineering
ANNAMALAI UNIVERSITY
BATCH’B’
Viii semester

3. INTRODUCTION
 A continuously variable transmission
(CVT) is a transmission that can change
steplessly through an infinite number of
effective gear ratios between maximum
and minimum values.
 This contrasts with other mechanical
transmissions that offer a fixed number of
gear ratios.
 The flexibility of a CVT allows the driving
shaft to maintain a constant angular
velocity over a range of output velocities.
3

4. ADVANTAGES
 This can provide better efficency than other
transmissions by enabling the operation to
run at its most efficient revolutions per
minute (RPM) for a range of operating
speeds.
 Alternatively it can be used to maximize the
performance of a machine by allowing the
machine to turn at the RPM at which it
produces peak power. This is typically
higher than the RPM that achieves peak
efficiency.
4

5. APPLICATIONS
 Many small tractors for home and garden
use have simple rubber belt CVTs
 Combine harvesters have CVTs. This
allows the operator to slow or accelerate as
needed to accommodate variations in
thickness of the crop.
 Some drill presses and milling machines
contain a pulley-based CVT where the
output shaft has a pair of manually-
adjustable conical pulley halves through
which a wide drive belt from the motor
loops.
5

6. PRINCIPLES OF SELF
ALIGNING
initial pressure
produced by the
weight of a power
disc is very small

7. Let P= initial friction force produced between disc and roller

8. STEPLESS REGULATION
CAN BE CARRIED OUT BY
 ELECTRICAL SYSTEM
 ELECTRONIC SYSTEM
 HYDRAULIC SYSTEM
 MECHANICAL FRICTION DRIVE AND
PRESSURE VARIATOR

9. ADVANTAGES OF STEPLESS
REGULATION SYSTEM:
 No loss in speed
 Can arrange speed adjustment without
stopping machine.
 It reduces time losses and very useful in
automatic tool
 Hydraulic drive avoids speed fluctuation

10. methods of Increasing range of
regulation
1.BY USING MANY
VARIATORS
Only belt
drive and
gear drive
is used

11. CHARACTERISTICS
 Here we donot use the full possibility of
3 variators.
 Too many speeds can be repeated.
 The system is not very much used
because we donot get many number of
speed.

12. 2.COMBINATION OF
VARIATORS WITH GEAR BOXES

13. CHARACTERISTICS
 Shaft 1st can have one constant speed.
 Shaft 2nd have a particular range of speeds.
 About shaft 3rd, three different speeds reduced
by gear ratios corresponding to any point on
2nd staff.
>>DIFFICULTIES
If the initial range is big then the ratio cant be
achieved as the gear box has its influence

14. 3.VARIATORS WITH
EPICYCLIC MECHANISM:

15. >DISADVANTAGES
>complicated to manufacture.
>can not be used in high speed.
>low efficiency if high range is produced.
>used only in feed drives.

16. ACKNOWLEDGEMENT:
>Design of Machine Tools, Basu S.K., and
Pal D.K.
>Machine tool Design and Numerical
Control, Metha N.K.
>GOOGLE SEARCH ENGINE

17. THANK YOU