Wave Spring
Here is one answer to the Smalley wave spring questions I've seen lately.
We went to the pro-stuff web site and downloaded a Smalley washer.
We needed springs for our application.
We modified the equation as shown below and all is well. If you find problems with it, please notify me so I can make the appropriate changes to ours.
Here is the equation for the datum curve of the washer we downloaded:
Wave Washer as downloaded from "pro-stuff" website:
/* For cylindrical coordinate system, enter parametric equation
/* in terms of t (which will vary from 0 to 1) for r, theta and z
/* For example: for a circle in x-y plane, centered at origin
/* and radius = 4, the parametric equations will be:
/* r = 4
/* theta = t * 360
/* z = 0
/*-------------------------------------------------------------------
"Change these values for your washer"
catalog_dia = .705
desired_ht = .085
num_waves = 3.5
"datum curve calcs below"
r =catalog_dia/2+D17
thk = D15
amp = desired_ht-thk
theta = t*355
z = amp/2*cos(num_waves*theta)
We modified this as follows:
Smalley Spirawave Washer Equation
************************************
/* For cylindrical coordinate system, enter parametric
equation
/* in terms of t (which will vary from 0 to 1) for r, theta
and z
/* For example: for a circle in x-y plane, centered at
origin
/* and radius = 4, the parametric equations will be:
/* r = 4
/* theta = t * 360
/* z = 0
/*----------------------------------------------
"Change these values for your washer"
catalog_dia = 1
desired_ht = .1
num_waves = 3.5
"Datum Curve parameters below"
r =catalog_dia/2+D17
thk = D15
amp = desired_ht-thk
theta = t*1440
z = amp/2*sin(num_waves*theta+270)+(desired_ht/360*theta)
Smalley Nested Washer Equation
***********************************
/* For cylindrical coordinate system, enter parametric
equation
/* in terms of t (which will vary from 0 to 1) for r, theta
and z
/* For example: for a circle in x-y plane, centered at
origin
/* and radius = 4, the parametric equations will be:
/* r = 4
/* theta = t * 360
/* z = 0
/*----------------------------------------------
"Change these values for your washer"
catalog_dia = .705
desired_ht = .085
num_waves = 4
"Datum Curve parameters below"
r =catalog_dia/2+D17
thk = D15
amp = desired_ht-thk
theta = t*720
z = amp/2*sin(num_waves*theta+270)+((thk/360)*theta)
Parameters requiring your input: catalog_dia, desired_ht, thk, theta
The parameters shown are examples.
We only modified "num_waves" and "z". When "num_waves" is 3.5,
you get a Spirawave. When it is 4, you get a nested spring.
This will give you a datum curve that you can sweep a protrusion along.
D15 is the thickness of the sweep and D17 is the width of the sweep.
I made the red text for differences between the two new equations.
The 270 in the z equation was to get the spring started in the right place so a shim could be added to the top and bottom as seen in the Smalley catalogs.