Optimize Analysis of Helical Gear

Nital D Patel

Introduction • Helical Gear is being used for high speed and

power operation.• Transmitting Power with the help of gear gives

better efficiency for any machines • Therefore it was use for power transmission in

various machines , automobiles , elevators , generators, lifting cranes , ship building, Oil Industry , Food and Labeling.

• For automobile industry gear with light weight and silence operation is given higher priority

• The contact ratio of teeth is large compare to the spur gear, result is that load carrying capacity is high and the operation performance very smoothly with low level of noise.

• Load Carrying Capacity is high compare to spur gear.

• Gear is messed in Parallel or cross Orientation

• Inclination of angle result is less deformation with time at any instant

Problem Formulation

• Heavy duty Machineries operated at high speed which induced large amount of stress and deflection in the gear , so for better efficiency stress and deflection in the gear should be minimized

• Bending stress and surface strength of the gear tooth should be considered as the main parameter for failure of a gear , so that determination of stress is to find out for minimize the failure of gear

• Due to inclination of tooth, helical gear creates an axial force in addition to transverse and radial load, this will effect on life of bearing. Axial force will be reduce by changing the inclination of helix angle on the gear

• Surface Failure due to high Contact stress.

• Contact stress can be calculate from inclination of angle.

• Deflection will be reduce by inclination of helix angle

• Strength of a gear should be determine form helical angle and material.

ANSYS Computational Procedures

• The geometry of gear with different helical angle is generated in a CATIA –V5 2014 with 20 , 25 , 30 and 35 degrees .

• Files is save in from of IGS format.• In Ansys gear geometry is import and Meshing the

geometry of the gear. • Boundary condition that is load on the teeth is applied.• The Von Misses Stress will applied to the surface of

teeth and edge to find out strength of material

Helical gear design in Catia v5

Helical gear geometry in Catia V5

Helical gear geometry in Ansys

• 7.5 hp, 1750 rpm motor , Ft=(200T)/d• Ft= 100000N

Tangential force on the tooth

Contact stress on tooth

Roots Bending Stress on roots of tooth.

15 20 25 30 35 405500

7500

9500

11500

13500

15500

7466.9

6419.8

75417248.4

10043 9980

15019

12521

Structual Steel Stress Analysis

Tooth Stress ( Mpa) Roots Bending Stress( Mpa)

Helical Angle ( Degree)

Toot

h an

d Ro

ots B

endi

ng S

tres

s (M

pa)

Structural steel stress analysis

15 20 25 30 35 405500

6500

7500

8500

9500

10500

11500

12500

13500

14500

15500

7476.4

6434.4

7524.67252

10052 9997.7

15098

12554

Gray Cast Iron Stress Analysis

Tooth Stress ( Mpa) Roots Bending Stress ( Mpa)

Helical Angle ( Degree)

Toot

h an

d Ro

ots B

endi

ng S

tres

s (M

pa)

Gray cast iron stress analysis

Stainless steel stress Analysis

15 20 25 30 35 405500

6500

7500

8500

9500

10500

11500

12500

13500

14500

15500

7461.7

6412.4

7550.67246.7

10038 9971.4

14978

12504

Stainless Steel Stress Analysis

Tooth Stress ( Mpa) Roots Bending Stress ( Mpa)

Helical Angle ( Degree)

Toot

h an

d Ro

ots B

endi

ng S

tres

s (M

pa)

Tabel1: Contact stress and Root bending stress Comparison for different helical angle and materials

Structural Steel Gray Cast Iron Stainless Steel

Angel Tooth ( Mpa) Edge ( Mpa) Tooth ( Mpa) Edge ( Mpa) Tooth ( Mpa) Edge ( Mpa)

20 10043 7466.9 10052 7476.4 10038 7461.7

25 9980 6419.8 9997.7 6434.4 9971.4 6412.4

30 15019 7541 15098 7524.6 14978 7550.6

35 12521 7248.4 12554 7252 12504 7246.7

Conclusion

• Strength of gear tooth is consider as main Parameter, to prevent failure, we have to find out the stress.

• Von misses stress for Contact and bending stress is analysis for Stainless steel , Structural Steel and Grey Cast Iron.

• As Increasing Helical angle, Contact Stress and Bending Stress is Analysis for these Geometry

• From the Analysis it was seen that for Stainless steel and Helical angle 25 Degree , Contact stress and bending stress is less compare to all other parameters.

• Stainless steel has good corrosion property and life cycle is more compare to grey cast iron, but cost is three time more.

• It produced more noise then grey cast iron . • Hardness of tooth Profile to be improve to resist failure

References

[1]B.Venkatesh,V.Kamala A.M.K.Prasad,Nov 1 ,2010, “ Design , Modelling and Manufacturing of Helical Gear”[2] Tribhuwan singh , Mohd Parvez, July, 2013, “Comporative Study of Stress Analysis of Helical gear using AGEMA and FEM”[3] J. Venkatesh, P.B.G.S.N. Murthy, March, 2014, “ Design and Structural Analysis of High Speed Helical Gear Using Ansys”[4] S.Sai.Anusha, P.Satish Reddy, P. Bhaskar, M.Manoj, December, 2014, “Contact Stress Analysis of Helical gear by Using AGMA and Ansys”[5] Govind T Sarkar, Yogesh L Yenkarkar , Dipak V Bhope, October , 2013, “ Stress Analysis of Heical Gear by Finite Element Method “