Mechanism Design and Mechanism Dynamics > Mechanism Design > Creating Mechanism Models > Measures, Graphs, and Evaluation Methods > Measures > Other Measures > About Cam Measures
About Cam Measures
Use cam measures to obtain information on the individual cams in a cam-follower connection. When you create your cam measure, you must select one of the cams in the connection.
* You can measure reaction forces and momentum changes at a cam-follower connection.
You can measure these components for cams:
Curvature—Measures the curvature (1/radius) at the point of contact for the specified cam surface. This measure is positive when the center of curvature lies toward the interior of the cam and negative when the center is toward the exterior. A flat cam surface has a curvature of zero.
* When you produce a graph for a cam measure–curvature, pressure angle, or slip velocity–the graph value goes to zero if your cams separate during the analysis. This is possible only for cams with liftoff. To decide whether the zero value on a graph of a curvature measure is due to a flat portion of the cam or due to cam liftoff, run the analysis with liftoff disabled.
Pressure angle—Measures the angle in degrees between the normal to the cam surface and the velocity vector of the contact point on the specified cam. The output values are between 0° and +90°.
Pressure angle on axis—Measures the angle in degrees between the normal to the cam surface and the velocity vector of the selected point. If an axis is selected, the point of its intersection with the cam plane is taken for velocity calculation. The output values are between 0° and +90°. A high pressure angle may indicate that the cam will jam or experience excessive wear.
* Best practice is to select a point on the follower shaft or on the roller follower axis to obtain the pressure angle in its classic sense.
Slip velocity—Measures the tangential velocity of the contact points on the selected cam surface relative to the contact point on the second cam. Cam 1 and Cam 2 have velocities of equal magnitude and opposite direction. Slip Velocity measures indicate the relative direction of the slip by expressing the velocity as a negative or positive number relative to the positive tangent shown when you create the Slip velocity measure.