Mechanisms
Project Overview
It is important to learn about a design mechanism. This includes understanding its degrees of freedom in terms of motion and rotation. Understanding mechanisms will allow us to learn more about a system or a part that was designed as a part of a machine.
4 Bar Mechanism
The program mathillustrations was used to understand more about how to make constraints in a mechanism. The purpose of the video shown below is to illustrate how the bar can rotate and will be placed on top and on the side of the rectangle. This was completed by using the tool "perpendicular bisector" to find points H and I which have a fixed coordinate. All of the lengths shown in the video are fixed so that when an angle is applied the whole mechanism that was designed will move.
Mechanisms analysis
The objective of the four bar mechanism is to understand and analyze the motion of two bearings, crank, rocker and extension when joined together by a hinge. This examination will be completed in the SolidWorks program where various properties such as the maximum torque and angular displacement will be determined. The image shown below is an example of what the mechanism looks like once each components has been joined together to reduce and restrict the Degrees of Freedom (D.O.F.)
From the images shown below, it can be seen that once the mechanism is completed, the total degree of freedom gets reduced to one.
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The following are files that traces the velocities in the X and Y directions at various locations of the extension. These files can be downloaded here: Trace 1, Trace 2, and Trace 3.
The next set of calculations is for the maximum value for the motor torque. The speed of the motor is set to 20RPM (3 seconds per cycle) and it will be applied to the crank.
The next set of calculations is for the maximum value for the motor torque. The speed of the motor is set to 20RPM (3 seconds per cycle) and it will be applied to the crank.
It can be seen from the plot on the right (Plot4) that the maximum value for the motor torque occurs at a value of 604 Newton-mm.
Afterwards, the angle of the crank for which the motor torque is maximum in each cycle was determined. ​​​Ass can be seen from the image on the right (Plot6), it can be seen that the angle of the crank in which the motor torque is maximum is 177.6 degrees.
A negative motor Torque can occur when the motor is at the synchronous speed. When the rotor is turning in the same direction but at a higher speed than the traveling speed, the motor torque will become negative