Design and Study of Piston assembly using Solidworks

AIM

1. To design and assemble each part of the piston assembly
2. To study motion analysis for the following three different conditions

S.no. Wrist Pin Offset Crank Speed (Rpm) 1 "0" mm 2000 2 10 mm Positive 2000 3 10 mm Negative 2000

3. To obtain the Linear displacement of the Piston Head for all the three cases.

GIVEN

All the simulation should be done for 2000rpm of crank.

BODY OF CONTENT

Introduction

Piston assembly consist of the several part i.e. piston head, connecting rod and end cap, wrist pin, crank.

PISTON

A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston ring. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder. In some engines, the piston also acts as a valve by covering and uncovering ports in the cylinder.

CONNECTING ROD AND END CAP

A connecting rod, also called a con rod, is the part of a piston engine which connects the piston to the crankshaft. Together with the crank, the connecting rod converts the reciprocating motion of the piston into the rotation of the crankshaft. End cap is used to close the connecting rod end.

CRANK

Crank is the rotating part in the piston assembly.

WRIST PIN

Wrist pin is used to connect the connecting rod and piston head.

STEPS OF DESIGNING OF PISTON ASSEMBLY

Before starting any design make sure the unit is in mm.

PISTON HEAD

1. Firstly, draw the sketch and provide the dimension according to mention in the figure below

2. After completing sketch go to revolved bose/base feature to convert it into 3D design as shown in the figure

3. After that make square shape over the surface of the revolved part to make a slot which holds the piston ring and again go to revolved cut feature in order to make the slot as shown in the figure.

4. After that choose linear pattern option to make two more slot similar to previous slot as shown in the figure

5. The circular through hole is to be needed on the bottom side of the surface of piston head which is used to hold the wrist pin inside it.

6. There is one more semi hole is to be needed for avoiding interference and to look design very interesting as shown in the figure.

7. Fillet is used where ever it is needed.

8. At last to hold the wrist pin we need to provide support like structure as shown in figure and mirror the same part in opposite direction also as shown in figure.

CONNECTING ROD

1. Firstly, draw the sketch and provide the dimension according to mention in the figure below

2. After that go to extrude feature and give the extrude thickness of 30mm as shown in the figure.

3. Make a circle on the surface and extrude up to 30mm in back direction of as shown in the figure

4. Make another concentric circle on the surface and extrude cut up to 30mm in back direction of as shown in the figure

5. At last provide fillet where ever it is required.

END CAP

1. Firstly, draw the sketch and provide the dimension according to mention in the figure below. And extrude that design up to 30mm

2. Make a circle on the surface and extrude up to 30mm in back direction of as shown in the figure

3. Make another concentric circle on the surface and extrude cut up to 30mm in back direction of as shown in the figure

4. At last provide fillet where ever it is required.

CRANK

1. Firstly, draw the sketch and provide the dimension according to mention in the figure below. And extrude that design up to 20mm.

2. draw the circle at one of its surfaces as shown in the figure and extrude upto thickness of 16mm.

3. make another circle and its another surface as shown in figure and extrude up to thickness of 20mm.

4. In order to make component more attractive we need to cut the upper and lower part.

5. At last we need to do mirror of the entire design of crank which is made up to previous steps in order to achieve the final design of crank.

WRIST PIN

1. Firstly, draw the sketch and provide the dimension according to mention in the figure below. And extrude that design up to 127mm.

2. At last do chamfering at both the end of the extruded part.

MATING OF ALL THE COMPONENT

Common mating for all three cases except the circle highlighted mating are shown in the figure.

For circle highlighted mating, different cases are discuss below

1. for ‘0’ offset

2. For ‘10mm positive’ offset

3. For ‘10mm negative’ offset

MOTION ANALYSIS

For doing motion analysis go to motion study make sure that motion add in is enable. And select the motion study in the place of animation.

1. Do proper contact between the mating part. Here I am taken steel (dry) as a contact between two components.

2. Provide motor for rotation of the crank. Here I have taken 2000 rpm

3. Set the frame per second according to design and select precise contact. Here I have taken 8400.

RESULT

Case1. For ‘0’ offset

Case2. For ‘10mm positive’ offset

Case3. For ‘10mm negative’ offset

Combined plot of 0, positive 10mm, negative 10mm offset

CONCLUSION

1. The linear displacement plot for all the cases is between Linear Displacement vs Time.
2. In all the plot it starts from 203 mm of linear displacement and time is up to 0.2 sec.
3. There is slight difference between all these three cases.
4. Offset is given in order to reduce wear and power loss.

YOUTUBE LINK

GOOGLE DRIVE LINK

https://drive.google.com/drive/folders/1a1T2HTSOErMVaamZ_CBNWElzz31xx0tT?usp=sharing