Step 16.2: Motion-Path FB, Ram-R

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Step 16.2: Motion-Path FB, Ram-R

Motion-Path: Ram-R and Ram-P

We can use the Motion-Path FB to build two new pseudo-Dyads:

Ram-R

Ram-P

An application of the Ram-R dyad is to model an engine valve cam where we want to specify the distance between the center of the rotating cam and the center of the roller on the rocker.

Another application is to specify the motion of a Linear Actuator that drives a scissor lift.


Kinematics of a Ram-R

GST-16-2-MD-RamR-F

Ram-R

The Ram-R is a similar to an R-R-R Dyad, but one of the Parts extends. Also, you only need two Parts in the kinematic-chain.

The Ram-R uses the Motion-Path FB to add a Motion-Point to a sketch-element (CAD-Line) in one Part.

We join the other Part to the Motion-Point with a Pin-Joint.

We connect the Motion-Path FB with a motion.


The Red Arrow in the image shows the Motion of the Motion-Point along the CAD-Line of one of the Parts.

tog_minusHow add a Ram-R

Add a 2D-Cam

GST-16-2-GA-RamR-09

Note: This cam is not going to be useful for an engine - it shows only one method.

STEP 1: Add the Cam Roller

1.Edit PartRed-1-17-Sq Add Circle, Add Dimension, Add Coincident Constraint  

The circle is now at the end-Point of the CAD-Line

2.Do Solid menu > Add Profile

3.Click the circleRed-14-9

 

GST-16-2-GA-RamR-10

STEP 2: Add the Cam-Part

1.Add a PartRed-14-10a and join it with a Pin-Joint at the left of the Line in the Base-Part*.

2.Add Motion-Dimension FB to the Part and connect to it a Linear-Motion FB

The new Part is horizontal - the Base-Value is 0º

* In the Select-Elements dialog-box, CTRL + CLICK the start-Point of the PartRed-14-10a and the start-Point (left) of the Line in the Base-Part.

 

GST-16-2-GA-RamR-11

STEP 3: Add the 2D-Cam

1.Do Machine elements > Add 2D-Cam

2.Click the new PartRed-14-10a as the Cam-Part.

3.Click th ProfileRed-14-9 as the Cam-Follower.

The 2D-Cam is now in the graphic-area.

 

GST-16-2-GA-RamR-12

Kinematics-Tree

We call this kinematic-chain the Ram-R Dyad

The Ram-R Dyad is represented by the R-R-R Dyad.

The rotating Cam-shaft is represented by a Rocker