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STUDY ON FACTORSAFFECTING BENDING STRESS
IN ASYMMETRIC GEARS
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Presented By:
Prabodh Sai Dutt R
1stSem M.Tech; CAMS
VVCE, Mysore
Under the guidance of:
Sri Thamme Gowda C.S.
Prof. Dept of Mechanical
VVCE, Mysore
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Gears are toothed members which transmit power / motion
between two shafts by meshing without any slip.
STUDY ON FACTORS AFFECTING BENDING STRESSES IN ASYMMETRIC GEARS
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Wooden Gears in olden wind
mills
Plastic gears
Compact Gears in modern wind mills
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Asymmetric Gears
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STUDY ON FACTORS AFFECTING BENDING STRESSES IN ASYMMETRIC GEARS
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Pressure Angle:
It is the angle at a pitch point between the line of pressure which
is normal to the tooth surface, and the plane tangent to the pitch
surface.
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STUDY ON FACTORS AFFECTING BENDING STRESSES IN ASYMMETRIC GEARS
Gear Tooth with different pressure
anglesPressure Angle and Profile Angle
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Peaking effect:
It is the phenomenon in which the top land of gear becomes
smaller with the increase in pressure angles and the tooth shape
becomes more and more pointed.
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Pointed gear tooth
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Table 1:Tip thickness for different pressure angles
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Comparison between symmetric and Asymmetric
Gears13-Dec-13
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STUDY ON FACTORS AFFECTING BENDING STRESSES IN ASYMMETRIC GEARS
Meshed gear tooth Stress distribution on gear tooth
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Gear model(drive/coast) von mises,N/mm2
Total
deformation,
mm20/20 47.06 0.003831225/20 44.21 0.003516030/20 41.03 0.003356535/20 37.98 0.0031818
Von Mises stress and distribution for symmetricand asymmetric gears
STUDY ON FACTORS AFFECTING BENDING STRESSES IN ASYMMETRIC GEARS
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Sl.
No. Description Value1 Number of teeth on
pinion 18 25 322 Module 2mm 4mm 6mm3 Pressure angle, Coast side 200 fixed4 Pressure angle, Drive side 200-350increment by 105 Back up ratio 1.2
Effect of module and number of teeth of a gear on the bending
stress
Gear tooth parameters with different module and
teeth
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STUDY ON FACTORS AFFECTING BENDING STRESSES IN ASYMMETRIC GEARS
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Tooth thickness at the critical section for different
modules.
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STUDY ON FACTORS AFFECTING BENDING STRESSES IN ASYMMETRIC GEARS
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Bending stress at the critical section for different number of
teeth.
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STUDY ON FACTORS AFFECTING BENDING STRESSES IN ASYMMETRIC GEARS
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Bending stress at the critical section for different modules
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STUDY ON FACTORS AFFECTING BENDING STRESSES IN ASYMMETRIC GEARS
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Displacement at the gear tooth root for different number of
teeth.
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STUDY ON FACTORS AFFECTING BENDING STRESSES IN ASYMMETRIC GEARS
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Potential Applications:
Automotive engineering
Aerospace engineering
Agriculture machines
Medical instruments
Toys
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Advantages of Asymmetric Gears:
Contact stress reduction on the drive flanks
Higher torque density (load capacity per gear size)
Reduced Weight & Size
Reduced Noise
Reduced Vibration
Disadvantage:
It can only be used for unidirectional power transmission
Higher cost of production
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CONCLUSION
Asymmetric gears have better performance in terms of load
bearing capacity compared to symmetric gears
Tooth peaking effect and safe contact ratio limits the degree of
asymmetry that can be achieved.
The bending stress in asymmetric gears decrease with the
increase in module
The bending stress decreases with the increase in number of teeth
of asymmetric gears
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References
1. Effect of Pressure Angle on Bending Stress and Deformation of Asymmetric
Spur Gear Using FEA- MR. K. D. DADHANIYA, PROF. K. P. HIRPAR, MR.
K. M. VYAS - IOSR Journal of Engineering Apr. 2012, Vol. 2(4) pp: 616-620
2. Improvement of Load Caring Capacity of Spur Gear by Asymmetric Teeth - D.
A. Patel, P. A. Vaghela, 5th International Conference on Advances in
Mechanical Engineering 2011
3. Parametric analysis of Asymmetric Spur Gear Tooth - G. Mallesh, Dr. V B
Math, Venkatesh, Shankarmurthy H J, Shiva Prasad P, Aravinda K
NaCoMM09, December 2009. Pg no 398-403
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Thank You
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