antique marine steam engine solidoworks project
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Final Project: Antique Marine Steam Engine
Table of Contents
I. Introduction 3
II. Mechanical Design: Parts 4
1. Case Sub-Assembly Parts 4 2. Powertrain Sub-Assembly Parts 6 3. Cylinder Sub-Assembly Parts 12 4. Valve Sub-Assembly Parts 19 5. Piston Sub-Assembly Parts 22 6. Link Sub-Assembly Parts 24 7. Handle Sub-Assembly Parts 27
III. Mechanical Design: Assembly 29
1. Case Sub-Assembly 29 2. Powertrain Sub-Assembly 33 3. Cylinder Sub-Assembly 36 4. Valve Sub-Assembly 39 5. Piston Sub-Assembly 43 6. Link Sub-Assembly 44 7. Handle Sub-Assembly 49 8. Final Assembly 53
IV. Mechanism Model Mechanics 57
V. Mechanism Kinematics 57
VI. Structural Analysis 58
VII. Conclusion 60
VIII. References 60
I. Introduction Steam engines are designed to perform mechanical work by utilizing the heat energy of compressed steam. Originally invented by James Watt, for whom the corresponding unit of power is named, the steam engine's advent was a critical development of the Industrial Revolution, paving the way for many other inventions, such as the steamboat, steam trains, and mills . Steam engines function by using the pressure of compressed steam to apply force to a piston or pistons, causing movement. For the purposes of this project, a steam engine was modeled that utilizes eccentric components to account for the motion of a single piston. The piston is linked to a powertrain assembly, which is housed within a case. The case is topped by a cylinder which includes a ratchet-like piece that indicates the speed, to which the spring-loaded handle is separately joined for control of the engine. The full assembly consists of seven sub-assemblies and 52 individual components, not counting standard fasteners. For the sake of modeling accuracy and time, standard fasteners were utilized from the McMaster-Carr website, which are available for public use for this purpose . The steam engine selected for this project was designed to be utilized in marine applications and resembles one that might have been used in the early 1900s.  This project was created using SolidWorks 2014. An image of the final product is shown in Figure 1. This report will include descriptions of each of the parts and instructions on how the sub-assemblies were created. It will also include analysis regarding the mechanical properties of the assembly and its kinematics, as well as structural analysis and a concluding statement.
Figure 1. Marine Steam Engine, full assembly
II. Mechanical Design: Parts 1. Case Sub-Assembly Parts 1.1 Case The case is designed to house the main components of the steam engine, designed to protect both the components inside the engine and to protect the operators from potential moving object hazards. Because it is designed to house many components with little room for error, it is a very complex piece, created from a large number of features, including boss extrusions, revolved extrusions, extruded cuts, shells, sweeps, circular patterns, and mirrored features, providing an opportunity to explore nearly every technique learned during this course. The case is composed of cast alloy steel and is shown in Figure 2.
Figure 2. Case
1.2 Throttle Support The throttle support is connected to the handle sub-assembly in the full assembly and rests on the side of the case in the sub-assembly. The throttle support began as a boss extrusion with cuts made to create the edges and to create the holes for fasteners. A revolved feature created the shaft, and additional extruded cuts created the threads along the shaft and the nested parts for where the fasteners will rest. The throttle support is composed of cast alloy steel. It is shown in Figure 3.
Figure 3. Throttle support
1.3 Bushing The bushing rests between the case and the main bearing cap in the assembly. It is a simple piece, created from a single linear boss extrusion. The bushing is composed of brass. It is shown in Figure 4.
Figure 4. Bushing
1.4 Main Bearing Cap The main bearing cap is connected to the case around the bushing in the sub-assembly. It is created with a pair of boss extrusions to create the main surfaces, with cut extrusions to create the holes for the bushing and fasteners. A revolved extrusion and cut revolve are used to create the hole in the center. The main bearing cap is composed of gray cast iron and is shown in Figure 5.
Figure 5. Main bearing cap
2. Powertrain Sub-Assembly Parts 2.1 Crankshaft
The crankshaft is what transmits the torque to the flywheel in the assembly. It also connects to the link and is forced to rotate by the pistons movement. The crankshaft was created using boss- and cut-extrusions. Due to the nature of the disks attached to it, the crankshaft could not be completed using a single revolve feature, and design intent could be better achieved by using extrusions. However, the cuts along the disc features were created by cut-revolving a triangle 360 degrees along their center lines. The part is composed of cast alloy steel. The completed part is displayed in Figure 6.
Figure 6. Crankshaft
2.2 Flywheel The flywheel is the last driven part in the assembly. One could connect a belt to the flywheel to drive another part. The flywheel was created using a series of extrusions and cuts,
and most notably, three circular patterns were used for the cuts and small arc features. The flywheel is composed of cast iron. The completed part is displayed in Figure 7.
Figure 7. Flywheel
2.3 Crank Pin
The crank pin connects the two halves of the crankshaft together. The crank pin was created using a single extruded boss. The crank pin is composed of aluminum bronze. The completed part is displayed in Figure 8.
Figure 8. Crank pin
2.4 Connecting Rod End Cap The connecting rod end cap surrounds one half of the crank pin as part of the connection to the piston. It is designed to rotate around the crank pin. This part was designed in one half, which was then mirrored along the center plane. This was done due to the symmetry of the part and saved time. The connecting rod end cap is composed of cast alloy steel. The completed part is displayed in Figure 9.
Figure 9. Connecting rod end cap
2.5 Connecting Rod Center Block
The connecting rod center block sits on top of the connecting rod end cap, with the caps pins sliding into its holes. It surrounds the other half of the crank pin as well. The connecting rod center block is composed of cast alloy steel. The completed part is displayed in Figure 10.
Figure 10. Connecting rod center block
2.6 Connecting Rod The connecting rod connects the crank shaft to the piston assembly. It sits on top of the connecting rod center block and is secured with hex bolts. One significant feature in this part is the one degree draft angle applied to the rod, increasing the diameter to its maximum at its
middle. The connecting rod is composed of cast alloy steel. The completed part is displayed in Figure 11.
Figure 11. Connecting rod
2.7 Connecting Rod Insert The connecting rod insert fits inside the top of the connecting rod. It was created with a single boss extrude. The connecting rod insert is composed of aluminum bronze. The completed part is displayed in Figure 12.
Figure 12. Connecting rod insert
The slipper serves a very important purpose. It surrounds the connecting rod insert such that the two parts circular cuts are concentric. The piston slides into the top hole of the slipper and a pin runs through it, connecting it to the connecting rod insert. This allows the slipper to rotate about the connecting rod insert, so that its top face can remain parallel to the floor, thereby
letting the piston move vertically. The slipper is composed of cast alloy steel. The completed part is displayed in Figure 13.
Figure 13. Slipper
2.9 Connecting Rod Pin
The connecting rod pin slides into the slipper and serves to allow it to rotate, letting the piston move vertically. It was created with a single revolved extrusion. The connecting rod pin is composed of cast alloy steel. The completed part is displayed in Figure 14.
Figure 14. Connecting rod pin
2.10 Slipper Guide The slipper guides connect to the slipper and slide along the interior of the case. Due to their dynamic cross-sections, lofts were used in their design. The completed part is shown in Figure 15.
Figure 15. Slipper guide
2.11 Collar half The collar half is a simple, two-feature part whose purpose is to hug the exterior of the case and help keep it in place. It was created with a boss extrusion to create the main structure and an extruded cut to create the holes for fastener attachment to the assembly. It is composed of cast alloy steel. The completed part is displayed in Figure 16.
Figure 16. Collar half
3. Cylinder Sub-Assembly Parts 3.1 Cylinder The cylinder is the main hub of this sub assembly, and was the most complicated part of this sub-assembly. All of the other sub-assemblies are connected to the Cylinder Sub-Assembly in some form. This means that the conn