MANSUR RAJ 13N71D0408 DRK INSTITUTE OF SCIENCE & TECHNOLOGY ASSEMBLY ANALYSIS OF GEARTRAIN IN DIFFERENTIAL
MANSUR RAJ 13N71D0408
DRK INSTITUTE OF SCIENCE &
TECHNOLOGY
ASSEMBLY ANALYSIS OF GEARTRAIN IN DIFFERENTIAL
ABSTRACT Differential is used when a vehicle takes a turn, the outer wheel on a
longer radius than the inner wheel. The outer wheel turns faster than the inner wheel that is when there is a relative movement between the two rear wheels. If the two rear wheels are rigidly fixed to a rear axle the inner wheel will slip which cause rapid tire wear, steering difficulties and poor load holding.
Differential is a part of inner axle housing assembly, which includes
the differential rear axles, wheels and bearings. The differential consists of a system of gears arranged in such a way that connects the propeller shaft with the rear axles.
The following components consists the differential: a) Crown wheel and pinion. b) Sun gears c)
Differential casing The main aim of the project is to focus on the mechanical design and
contact analysis on assembly of gears in gear box when they transmit power at different speeds at 2400 rpm and 6400 rpm. Analysis is also conducted by varying the materials for gears, Cast Steels and Aluminum Alloy.
The analysis is conducted to verify the better material for the gears in the gear box at higher speeds by analyzing stress, displacement and also by considering weight reduction.
INDEX1) Differential gear box
2) Calculations
3) Assembly
4) Analysis
5) Comparison of results
DIFFERENTIAL GEAR BOXFunction:- i) Transmit motion from engine
shaft to rear wheels. ii) Maintain different speeds of
rear wheels while turning .Components :- 1) Crown Wheel 2) Sun Gear 3) Casing
TANGENTIAL LOAD (Wt) WT= ( σO x Cv).b.Π. m. y1
P((L-b)/L)Cv= velocity factor =3/3+v V= peripheral speed in m/s=b=For satisfactory operation of the bevel gears the face width should be
from 6.3m to 9.5m So b is taken as 9.5mm= moduley1p= tooth form factor = 0.154-0.912/ TE
L= slant height of pitch cone DG= pitch diameter of gear Dp= pitch diameter of gear σO=allowable static stress =σu/3
DESIGN CALCULATIONS OF DIFFERENTIAL
DYNAMIC LOAD (WD) WD= WT+ WI
WD = WT +
V = pitch line velocity B = face widthC = dynamic factor in N/mm=
K = 0.111 for 20° full depth involute systemEP = young’s modulus for material of pinion in N/mm2
EG = young’s modulus for material of gear in N/mm2
e = tooth error action in mm (value for module=10 used in precision gears is e=0.023)
SPECIFICATIONS OF ASHOK LEYLANDMaximum power= 162 bhpBevel gearing arrangement =90°
Diameter of crown wheel = DG= 475mmNumber of teeth on gear = TG =50Number of teeth on pinion = TP = 8Module = m=DG/TG=475/50=9.5=10Diameter of pinion =m x TP=10x8=80mmBrinell hardness number Ni.cr alloy(BHN)=444Brinell hardness number Al alloy(BHN)=140
σu=ultimate tensile strength(Ni.cr)=380 Mpa σu=ultimate tensile strength(Al alloy)=517
Mpa
ASSEMBLY
INTRODUCTION TO CAD (PRO-E)CAD is used in the design of tools
and machinery and in the drafting and design of all types of buildings, from small residential types (houses) to the largest commercial and industrial structures .
PRO-E It is a parametric &
feature based software, for developing of Design structures.
MODEL OF DIFFERENTIAL GEAR
ASSEMBLY OF A MODEL
ANALYSIS
INTRODUCTION TO FEAFinite element method was initially developed for the analysis of different structures.
DISCRETIZATION The process of subdividing a problem entity
Into smaller section called as discretization
The next step after discretization is meshing of a structure with respect to provided data
ANSYS
ANSYS is analysis part of 3d modeling software.
Three basic steps involved in analysis are i)Pre-processor [input like material properties load ,
meshing etc.]
ii)Solution [solving]
iii)Post-processor [output & results]
PROCESS OF ANALYSIS IN ANSYS
STRUCTURAL ANALYSISi) Applying material properties
ii) Fixed geometryiii)Applying loadsiv) Meshing v) Solving
vi) Results
MATERIAL PROPERTIES
NAME OF THE MATERIAL
Nickel Chrome Steel Aluminum alloy
YIELD STRENGTH 1.72339e+008 N/m^2 1.65e+008 N/m^2
Elastic modulus: 2e+011 N/m^2 7e+010 N/m^2
Poisson's ratio 0.28 0.33
Mass density 7800 kg/m^3 2600 kg/m^3
Shear 7.7e+010 N/m^2 3.189e+008 N/m^2
Stress 2.29414 N/mm^2 3.19018 N/mm^2
Fixed geometry Applying loads
Meshing
STUDY RESULTS OF ALUMINUM ALLOY
Stress Displacement
Strain
6400 RPM
RESULTS TABLENi Cr Alloy Steel Aluminum Alloy
TANGENTIAL LOAD (N) 2093.8 2922.51
DISPLACEMENT (mm) 0.00615413 0.0241696STRESS (N/mm2) 2.29414 3.19018
STRAIN 1.0400e-5 4.1593e-5
STATIC LOAD (N) 56141.9 18143.3DISPLACEMENT (mm) 0.164988 0.150063
STRESS (N/mm2) 63.5052 19.8068
STRAIN 0.000280882 0.000258239
2400 RPM
6400 R P M Ni Cr Alloy Steel Aluminum Alloy
TANGENTIAL LOAD (N) 915.177 1276.18
DISPLACEMENT (mm) 0.00268949 0.0105555
STRESS (N/mm2) 1.03521 1.36296
STRAIN 4.57869e-6 1.80467e-5
STATIC LOAD (N) 56141.9 18143.3
DISPLACEMENT (mm) 0.164873 0.11763
STRESS (N/mm2) 61.8853 19.3772
STRAIN 0.000290205 0.000256567
CONCLUSION In our project we have designed a differential gear box for Ashok Leyland 2516M. Loads are calculated when the gears are transmitting different speeds 2400rpm and 6400 rpm and different materials Alloy Steel, Aluminum Alloy.
Structural analysis is done on the differential gear box to verify the best material by taking in to account stresses, displacements, weight etc.
By observing the structural analysis results using Aluminum alloy the stress values are within the permissible stress value. So using Aluminum Alloy is safe for differential gear. When comparing the stress values of the two materials for all speeds 2400rpm and 6400 rpm, the values are less for Aluminum alloy than Alloy Steel.
And also weight of the Aluminum alloy reduces almost 3 times when compared with Alloy Steel since its density is very less. Thereby mechanical efficiency will be increased.
By observing analysis results, Aluminum Alloy is best material for Differential.
T H A N K Y O U
Q U E R I E S