4-Bar Tutorial

The purpose of this tutorial is to become familiarized with the use of SolidWorks Assemblies and Motion Studies to assemble, animate, and analyze the kinematics and dynamics of a 4-bar linkage. In this tutorial, a 4-bar linkage will be assembled, and various properties relating to the linkage will be extracted, such as its locus, component velocities, motor torques, reaction force, and power consumption.

With the exception of the power consumption plot, all other results were generated at 25 frames per second operating at 20 RPM

Trace Points

The above image shows the motion locus trace of 3 points on the Extension: 1/4 length, 1/2 length, and 3/4 length

X and Y velocity components of the center of the extension

Moror Torque as a function of time

As seen here, the maximum motor torque applied during the cycle is -0.72 Nm. Negative values of torque imply that to maintain constant RPM, the motor must apply torque in the reverse direction. If the links are lined up such that gravity and momentum accelerate the links, torque must be applied in the opposite direction to counteract this.

Motor Torque as a function of crank angle

The angle at which the maximal motor torque is applied is 158 degrees, as shown in the above plot. Note that in a polar plot, the radial axis plots the magnitude and not the direction, thus not distinguishing between positive and negative values

Bearing Load on crank and rocker bearings

The maximum load exerted on the crank bearing is 14N, while the maximum on the rocker bearing is 10N. These occur at different places in the cycle, as seen above.

Power Consumption @ 600 RPM

To operate this 4 bar linkage, a motor with a power of at least 1150W must be selected, as this is the maximum power consumption at 600 RPM.

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