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