FINAL INDEPENDENT PROJECT
Aim: MBD SIMULATION ON PROPELLER SHAFT AND DO MOTION STUDY
Objective:
- Design a simple propeller Shaft without Slip yoke.
- Perform the Motion study to find the angular velocity/momentum.
- Record the animation.
Detailed Objective:
Design a propeller shaft assembly (simple assembly without sliding yoke), with the design perform motion study analysis to find angular velocity and acting forces.
Propeller shaft assembly will be placed on the base keeping the 2 ends at a different height to record the simulation and also get the result from the analysis. So in short, I am trying to study the propeller shaft motion study with the assumption/exception of NO TURNING as we are not having sliding yoke in design to compensate the length of shaft while the vehicle turn in any direction.
Reason, why we are no including sliding yoke, is because we will fix the propeller shaft on the fixed base and thus the base will not move in any direction which omits the need of sliding yoke.
Findings:
I am trying to find the angular velocity/momentum.
Introduction:
What is the Propeller shaft?
: A drive shaft, driveshaft, driving shaft, tail shaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a mechanical component for transmitting torque and rotation, usually used to connect other components of a drive train that cannot be connected directly because of distance or the need to allow for relative movement between them.
As torque carriers, drive shafts are subject to torsion and shear stress, equivalent to the difference between the input torque and the load. They must, therefore, be strong enough to bear the stress while avoiding too much additional weight as that would in turn increase their inertia.
To allow for variations in the alignment and distance between the driving and driven components, drive shafts frequently incorporate one or more universal joints, jaw couplings, or rag joints, and sometimes a splined joint or prismatic joint.
Application and significance:
- Functions of the propeller shaft
In most of the automotive vehicles, the engine is located at the front and the rear wheels of the vehicle are being driven. This arrangement stipulates a longer propeller shaft to be used. In some arrangements, two or three propeller shafts are used to make up the length.
In some vehicles, the engine is kept at the front and the front wheels of the vehicle are being driven. In some other vehicles, the engine is at the rear and the rear wheels are being driven. For such arrangements, a short propeller shaft is used to drive each wheel.
The engine and the transmission unit are attached to the vehicle frame with some flexible mounting. The rear axle housing with differential and wheels are attached to the vehicle frame by suspension springs.
Due to the above arrangement, the transmission output shaft and the input shaft to the rear axle housing are in different planes. This compels the propeller shaft that connects these two shafts to be kept inclined.
Further, whenever the rear wheels encounter irregularities in the road, the rear axle housing moves up and down, compressing and expanding the suspension springs. As this happens, the angle between the transmissions output shaft and the propeller shaft changes. Further, the length to be occupied by the propeller shaft also changes.
The variation in the length of the propeller shaft happens because the propeller shaft and the rear axle housing rotate on arcs with different points as their centers of rotation.
The rear axle housing moves in the shorter arc than that of the propeller shaft. This is because the center of the rear axle housing arc is the point of attachment of the rear spring or control arm to the vehicle frame. This aspect causes a reduction in the length occupied by the propeller shaft as the angle between the transmission and the propeller shaft increases.
- Propeller Shaft:
Propeller Shaft is the shaft that transmits power from the gearbox to the differential gear in a motor vehicle from the engine to the propeller in a boat or flying machine.
The propeller shaft sometimes called a Cardan shaft, transmits power from the gearbox to the rear axle. Regularly the shaft has a tubular section and is made in maybe a couple of piece construction.
The two-piece arrangement is supported at the midpoint by an elastically mounted bearing. Short drive shafts are incorporated for the transmission of power from the last drive assembly to the road wheels in both front and rear-wheel drive layouts.
- Types of Propeller Shaft:
- Single-Piece-Type Propeller Shaft:
Used in vehicles with a short distance between the engine and axles, and MR based four-wheel-drive vehicles.
The friction welding adopted at the junction contributes to an improvement in the strength, quality, and durability of the junction.
- 2-piece-type/3-piece-type Propeller Shaft:
Utilized as a part of vehicles with a long distance between the engine and axles, and Front engine front-drive base four-wheel-drive vehicles.
The division of the propeller shaft into two- or three-parts allows the critical number of revolution to lowered preventing vibration issues from occurring when the overall length of the shaft increased.
- Main Components of Propeller Shaft:
- The propeller shaft transfers engine torque to the rear axle through one or more universal joints.
- The splines on the ends at the propeller shaft fit perfectly into the splines in the sleeve. This permits a length variation between the driving and the driven unit to vary slightly without damaging the output and input bearings.
- The main bearing support and guide the propeller shaft.
- The flanges associate the propeller shaft to the gearbox.
- Requirements of Propeller Shaft:
For achieving efficient functions, the following are expected in a propeller shaft
- High torsional strength: Therefore, they are made of solid or hollow circular cross-section
- Toughened and hardened: Therefore, they are made of superior quality steel and are induction hardened
- Efficiently jointed: Therefore they are generally welded by submerged are carbon dioxide welding process.
- Dynamically balanced: Since the phenomenon of whirling may be critical at higher speeds, therefore, propeller shafts are tested on an electronic balancing machine.
- Reduced thrust loads: Since resonance is dangerous for the life of the shaft. It also transmits excessive dynamic force to the shaft's end supports, and so its occurrence should be avoided.
Design:
Below are the screenshot attached for the 3D model design.
Solidworks Part Design Procedure:
For each part, open Solidworks and select a new part and also select the unit system mm. Moreover, make sure to make the extrude as default as possible. (This is very important to maintain consistency in part and it will be useful while doing the assembly)
Part 1: Flange Yoke
The open new part, select a front plan, and select circle to draw, now draw 2 circles and constrained the sketch for the defined sketch as shown below and extrude 30mm;
Once you drew this, draw a rectangle at the top as shown above and extrude it 130 mm. after this use fillet as shown or as you prefer.
Now draw a circle on the top face of the rectangle and do the cut extrude. After these, as you prefer, you aesthetically improve the sketch by doing some extra extrude and fillet.
Once you are done with one of the sides, either you can mirror the feature or you can cut the half-plane, and then you can mirror the developed solid across the top plane. The final output is as shown below;
Part 2: Cross/Spider
Draw circles as shown below and give the constrains to fully define the sketch as shown, then exit the sketch and select extrude for 100mm and then again extrude the for 10mm at the ends of each extrude drawing a large circle after the converted entity of smaller circle. Use fillet as you prefer and you will get the below results. Save the part.
Part 3: End Shaft
Draw a sketch and give the fillets and also fully define the sketch as shown below;
And extrude the sketch, save the part.
Part 4: Cotter Pin
Draw the sketch using the circle as shown below and give the dimension and other constraints to fully define the sketch; after this exit the sketch and choose to revolve extrude option as shown below and save the part.
Part 5:
Draw a sketch using Circle as shown below and give the dimension and other constraints to fully define the sketch, after this exit the sketch and do extrude as shown below and save the part.
Part 6: Pin
Small pin of 15mm dia and 100mm extrude and save it.
Part 7: Base
Draw a sketch with lines and extrude it with midplane and give cut extrude holes on both vertical faces at given dimensions and save the part.
Assembly:
Go to new and select assembly and insert all the parts and use below mates;
And then save the assembly but before doing so just check all the parts are well constrained that is they are no moving in an unnecessary direction.
Motion Study:
Now go to SOLIDWORKS ADD ONs and select SOLIDWORKS MOTION
Now select the MOTION ANALYSIS for the motion study.
Material for all parts;
For all the motion study the contact will stay the same as shown below;
For high definition values &more accurate values we took 7200 frames per second with precise contact, this feature will help us to get a well-defined plot.
Speed: 1200 RPM
- Angular Velocity for the input shaft and output shaft:
Input Shaft:
Output Shaft:
Angular velocity for input and output shaft is the same, both the shaft shows some flickers but the output shaft has more than the input shaft.
Shaft:
The angular velocity of the shaft is changing over a fixed cycle and the average speed is the same as other parts.
2. Angular Momentum
Input Shaft:
Input Flange:
Output Flange:
Output Shaft:
Angular momentum is the same for input & output Shaft, and input flange & output flange.
Shaft:
Angular Momentum is very different for propeller shaft as it is longer in length.
Result and Explanation:
As we can see in plots for angular velocity and angular momentum, the results are the same as the input given to the motor and that hat we were looking for, as the parts which reflect the same angular velocity and angular momentum are not that long and has close contact with each other. Whereas shaft which is very long as compared to other parts and does not occupy close contact with other parts and also has the center of gravity at distance makes it a little different. Thus the difference can be seen in the plot for angular velocity and angular momentum. Although the angular velocity median is the same.
Videos:
Errors or issues I faced:
None
Reference: