The document discusses methods for reducing noise in a gear train. It identifies sources of noise such as worn teeth and backlash. It then presents several component-oriented concepts for reducing noise, such as using scissors gears, torsion springs, or gears with elastomeric material between them. The document also discusses selecting appropriate gear materials and redesigning the gear train layout, such as using fewer gears or bevel gears, to reduce noise.

1. NOISE REDUCTION
IN
GEAR TRAIN
Presented by
G RAJU (14481D1503)

3. Noise due to :
Worn tooth

4. Position errors :

5. Worn tooth :

6. Misalignment :

7. Transmission Error :

8. Gear rattling phenomenon and hammering noise:

9. GEAR TRAIN HAMMERING NOISE :
Because of the camshaft torque variation and the existing of
gear backlash, gear hammering happens .

10. Backlash phenomenon :
Clearance or lost motion in a mechanism caused by
gaps between the meshing teeth.

11. How to reduce noise :-
1.Component oriented concepts:
 Using scissors gears

12.  Advantages and disadvantages :
 Eliminates backlash across the gear train because of relative
motion between the gears.
 Reduces noise .
 Manufacturable and available in the market.
× Expensive .
× Heavy because of presence of springs and bolts and retaining
rings .
× The design increases complexity .

13.  Torsion spring system:
A torsion spring is used to connect the gears and the
relative motion between the gears is absorbed by the
torsion spring.

14.  Radially arranged springs:
The gears are arranged with springs positioned radially, In
order to facilitate the relative motion, one of the gears is fitted
on the shaft and the other.

15. Gears with an elastomeric material :
The gears contain an elastomeric material between the
gears in order to facilitate relative motion between the
two gears. The elastomeric material could be rubber or
any other available material.

16. Seeger rings :
For narrower gears it might not be possible to fit
springs or it could be a problem in producing the
required amount of torsioning .

17. 2.Material Concepts:
A number of different factors and properties have to be
considered while choosing an appropriate and efficient material
for an engine gear. These include.
• Material availability
• Cost
• Fatigue limits
• Temperature limits
• Fracture toughness
• Load and torque carrying capacity
• Manufacturing requirements
• Weight
• Treatments
• Machinability
• Operational characteristics
• Damping characteristics
• Corrosion and wear resistance

18. The other main considerations while selecting material are :
 Powder Metallurgy
 Surface densification
 Thermal expansion
 Weight perspective

19. 3. Redesigned layout concepts:
 Eccentric/Elliptic drive mechanism:
An idea came up to reduce/eliminate the number of gears and
optimize the gear train.
an idea came up to reduce/eliminate the number of gears and
optimize the gear train.
Advantages and disadvantages of the elliptic mechanism:
 Less number of gears
 minimizing parts
 Lower weight potential
 Lower noise and vibration potential
 Simple mechanism

20. × Counterweight balancing is very crucial and it could add weight
to the system .
× Not yet tried for heavy duty applications.
 Bevel gear timing system :
The basic idea was to reduce the number of meshes in the gear train
between the gears thereby reducing the friction and power losses.
Moreover this might also reduce the gear rattle and noise generated
at the different gear meshes.

21. Bevel gear timing system

22. 4 .Layout improvement solutions for gear train:
 Effects of gear inertia
 Effect of meshes
 Effect of auxiliaries
5. Competitor Benchmark