computer aided design of slider crank mechanism

COMPUTER AIDED DESIGN OF SLIDER CRANK MECHANISM

D.Sreekala , II M.Tech CAD

S.Karppuddiyan , Sr.Lecturer

Dr.Kingsley Jeba Singh ,Professor

Department of Mechanical Engineering , S.R.M.University,Kattankulathur-603203 Kancheepuram Dist. TamilNadu. E-Mail: [email protected] Slider crank mechanism is a well known application in an engine which is widely Used to convert

reciprocating to rotary motion and composed of three important parts i.e., crank is a rotating disc, slider

which slides inside the tube and connecting rod which joins the parts together.The best examples of crank

slider –Mechanism are steam train and cylinder of an internal combustion engine.

Computer Aided Design software is developed for generating slider crank –mechanism by inputting

configuration values using object oriented programming approach of visual basic and visualizing the

model in 3D modeling software[Solid Works].

The software graphical features were used to give a visual interpretation of the solutions . The software

effectiveness was tested on a no: of numerical examples,Some of them are outlined in this work.

Keywords: Computer Aided design , Crank , Slider , Connecting Rod ,Visual Basic 6.0 , Solid works.

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INTRODUCTION

Modern trends in the design of mechanisms emphasize economical design analysis

By means of computer aided design techniques .Computer-aided design (CAD) is the use of a wide range

of computer-based tools that assist engineers and other design professionals in their design activities . This

has however over the last 20 years been overtaken by 3D parametric feature based modeling. Components

are created using Solid modeling are assembled into a 3D representation of the final product, this is called

as Bottom-up Design .

Mechanism is the arrangement of connected parts in a machine in order to Accomplish desired force

and motion transmission , which is considered to be an assembly of mechanical items designed to achieve a specific purpose with in a machine. There are clearly an infinite number of mechanisms available, but concentrated on specific one is slider- crank mechanism. The piston , cylinder , crank and connecting rod combination is known as a Slider-Crank Mechanism.The purpose of this is to convert the linear motion of the piston to rotational motion of the crankshaft. One common application of the mechanism is in IC Engines. A . MECHANISM DESIGN : The creation of a scheme for the assembly of a machine . This involves

1. Conception of an arrangement of components or elements or parts which will accomplish the desired purpose.

2. Definition of the geometry of each part. And

3. processing



Slider-crank mechanism, (a) Mechanism, (b) Graph of mechanism. R = pin joint; P = sliding joint

In this slider crank linkage mechanism , the crank is in pure rotation and the piston is

In pure translation [which moves back and forth in a straight line]

Principal parts of slider-crank mechanism



MECHANISM DESIGN

The components of mechanism Crank ,Connecting rod ,Piston , wrist pin and Cylinder are designed using relevant design equations . INPUT PARAMETERS: [a]. Diameter of the crank shaft Dc [b]. Radius of the crank Rc [c]. Diameter of the piston Dp DESIGN CALCULATIONS: [a]. length of the connecting rod :

Lc = 4.5* Dc

[b]. Diameter of the crank pin : Dcp = 0.5* Dc

[c]. Diameter of the large boss:

Dlb = 1.8 *Dc

[d]. Diameter of the small boss:

Dsb = 0.9*Dc

[e].Diameter of the big end of the connecting rod : Dbc = 1.5* Dlb [f]. Diameter of the small end of The connecting rod : Dsmc = 0.45* Dbc [g]. Diameter of the wrist pin:

Dwp = 0.5*Dsmc [h]. Diameter of the cylinder:

dc = 2*Dp



SLIDER CRANK MODEL



INTRODUCTION TO VISUAL BASIC

Visual basic is the event – driven programming language and integrated development environment from

Microsoft for its COM programming model,which is also considered a relatively easy to learn and use

programming language.

INTERFACING VB WITH SOLIDWORKS:

Automation via the SolidWorks Simulation API can greatly enhance productivity and help designers and

engineers quickly pre-process or post-process information external to the user-interface capabilities.

Simple software package can be designed that allows this type of mechanism design. Such a package would

require a simple user front end and easy to understand API. Users should be allowed to fully integrate the

software package into their own code with the ability to either choose to specify an input



ACKNOWLEDGMENT

I ,sreekala.D wish to thank Dr. kingsley Jeba singh ,professor and also

thanks to S. Karppudiayan, Sr. Lecturer.



REFERENCES

THEORY AND PROBLEMS OF MACHINE DESIGN Hall * Holomenko A.R,Laughtin HG

MECHANICAL ENGINEERING DESIGN S higley Je, Mischke CR, 6th Edu.New york, McGraw Hill 2001

MICROSOFT DEVELOPER NETWORK,Help for Visual basic6.0

MACHINARY AND MECHANISM Robert l. nordon



computer aided design of slider crank mechanism

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