Edit the Design-Set.
The objectives are to edit the four dimensions in the Design-Set, and
•Make sure the maximum radius of the smaller cam does not exceed :
•Minimize the Pressure-Angle
We will use a Cam-Data FB and a Graph FB to plot the Pressure Angle and the Radius-of-Curvature* to find the maximum radius of the Cam.
Note: *
We could also use a Measurement FB to measure between the the center of the Cam-Shaft and the contact-point between the Cam and the Cam-Roller.
Plot the Cam Radii of Curvature with a Graph:
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STEP 1: Edit the 2D-Cam to display the 'smaller' cam. 1.Mechanism-Editor: Double-click the 2D-Cam in the graphic-area (or see How to open a dialog-box) The Cam Display and Properties dialog should be open. 2.Click Cam Display and Properties dialog-box > Display tab > Cam Visibilities > You can see you can display: Cam 1, the Pitch-Curve, and / or Cam 2. We need to know if Cam 1 or Cam 2 is the smaller cam. The Cam # is next to the contact-point between the Cam and the Cam-Roller - it is a number 1 or 2. In this case, next to the smaller cam there is the number 2. 3.Click Cam Display and Properties dialog-box > Display tab > Cam Visibilities >Cam 1. |
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STEP 2: Add a Cam-Data FB and Graph FB to the graphic-area
We need to link the 2D-Cam in the model with the Cam-Data FB. 3.Mechanism-Editor: Edit the Cam-Data FB to open the Cam-Data Dialog-box (or see How to open a Dialog-Box) 4.Mechanism-Editor: Click the 2D-Cam in the graphic-area (or Assembly-Tree), Click The 2D-Cam is now linked to the Cam-Data FB. 5.Mechanism-Editor: Connect the Radius-of-Curvature output-connector(3) of the Cam-Data FB to the Y1 input-connector of the Graph FB. 6.Mechanism-Editor: Connect the Pressure-Angle output-connector(4) of the Cam-Data FB to the Y2 input-connector of the Graph FB. |
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STEP 3: Make sure the plot of the Radius-of-Curvature is for Cam 2 (Note: the default is Cam 1) 1.Double-click the Graph FB icon in the graphic-area (or see How to open a Dialog-Box) The Graph is now open. Note: Each wire has up to 3 data-channels. We can plot one data-channel with each wire we connect to an input-connector of the Graph FB. To select which data channel we plot, we use the Y-input: Cam-Data drop-down to the right of the plot area in the open Graph. We need to select Radius-of-Curvature 2 for Cam 2. 2.Click Graph > Y-input data-channel > Radius-of-Curvature 2 |
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STEP 5: Edit the Minimum and Maximum Scales for each Plot. Notes: The Y-axis scale for the Radius-of-Curvature can have a massive range - from plus to minus infinity. It is easier to use the plot if we set the Minimum and Maximum values of each Y-input with the Graph Settings.
Set the Maximum and Minimum Radius of Curvature Plot 1.Graph-Settings > Title and Input Selection > Y1 : Rad of Curvature2 (enter a Graph Title if you want) 2.Graph-Settings > Y-axis : De-select Auto-scale 3.Graph-Settings > Y-axis : Y maximum = 200 ; Y minimum = 0 Set the Maximum and Minimum Pressure-Angle 4.Graph-Settings > Title and Input Selection > Y2 : Pressure-Angle 5.Graph-Settings > Y-axis : De-select Auto-scale 6.Graph-Settings > Y-axis : Y maximum = 60 ; Y minimum = -60 (update again later as Pressure Angle improves) Note: I would normally set the maximum and minimum Pressure-Angle values to ±35. However, the Pressure-Angle is very biased to a large negative value. Hence, we can set a larger range, and reduce it when the Pressure-Angle improves. 7.Close the Graph-Settings dialog. Save your model |
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