CAM design

EML 2023 Modeling, PartsLecture 1.11 Equation Driven CurveEML 2023Department of Mechanical and Aerospace Engineering1Equation Driven Curve2

y= 2 x2 3 x + 2, x = 0.. 2EML 2023Department of Mechanical and Aerospace Engineering2Parametric Equations3

x = sin(t)y = 2 cos(t)t = 0 .. 1.25EML 2023Department of Mechanical and Aerospace Engineering

Parametric Equations4x = sin(t)y = 2 cos(t) + tt = 0 .. 4EML 2023Department of Mechanical and Aerospace EngineeringWhat is a cam?

5EML 2023Department of Mechanical and Aerospace Engineeringcam and follower

6EML 2023Department of Mechanical and Aerospace Engineeringdisc cam with flat follower

7EML 2023Department of Mechanical and Aerospace Engineeringrocker cam

8EML 2023Department of Mechanical and Aerospace Engineering4 cycle engine

9EML 2023Department of Mechanical and Aerospace EngineeringOur Problem

L1 = 2L2 = 3 = 12010EML 2023Department of Mechanical and Aerospace EngineeringOur problemDesign a disc cam (for use with a flat follower) such that:follower height is L1 when cam angle is 0follower height is L2 when cam angle is the relationship between the height, L, and the cam angle, , is linear

We need to get the function of the cam profile and then draw a curve in SolidWorks that exactly models this profile.

11EML 2023Department of Mechanical and Aerospace EngineeringDetermine cam profile equation

Would like to have y = f(x).We want a linear relationshipbetween L and .L = A + BDetermine A and B.

When = 0, L = L1 ; when = , L = L2

L1 = A (0) + BL2 = A () + B

12EML 2023Department of Mechanical and Aerospace EngineeringCam profile equation

Now well get the x and y coordof point A (an arbitrary point) xA = L cosyA = L sinsubstitute for LA

13EML 2023Department of Mechanical and Aerospace EngineeringCam profile equation

We would like to have y as a functionof x.Instead we have y and x as a function of . This is called a parametric representation of x and y.A

14EML 2023Department of Mechanical and Aerospace EngineeringCam profile equation

Lets look at a numerical example:L1 = 2 (when = 0)L2 = 3 corresponding to = (120) A

15EML 2023Department of Mechanical and Aerospace EngineeringCam profile equation

Plot the x,y coordinates as variesfrom 0 to

A

16EML 2023Department of Mechanical and Aerospace EngineeringCam profileHow do we get this exact curve into SolidWorks?make a sketch with an equation driven curve (parametric)button is under the spline button

17L1 = 2L2 = 3 = 120EML 2023Department of Mechanical and Aerospace EngineeringCam Profile

equation driven curve (parametric)18L1 = 2L2 = 3 = 120EML 2023Department of Mechanical and Aerospace Engineeringcomplete the profile

19EML 2023Department of Mechanical and Aerospace Engineeringcomplete the profile

20EML 2023Department of Mechanical and Aerospace Engineeringcomplete the profile

21EML 2023Department of Mechanical and Aerospace Engineeringprofile

working region of cam22EML 2023Department of Mechanical and Aerospace Engineering

23EML 2023Department of Mechanical and Aerospace Engineering