Question on Calculating Force on a Roll Pin

[ryandias]

I am not sure how to calculate the force due to compressing the spring pin (diameter) into a hole.

Can anyone enlighten me? Is the Force exerted on the hole simply delta diameter * Spring force?

This is the type of pin I am refering to;

http://www.micromatic.com/images/3/300x300/100-302.jpg

On my spec sheet I see;
JIS B2808-1990
and
Strength Firmness = 70+/-5 (JIS K 6301)

(I don't have any information on this JIS K 6301 specification. Could anyone enlighten me?)

 

[whang333]

Downward force = coefficient of static friction X Spring Force


coefficient of static friction for steel to steel is

.15 to .25

Hope this will help you

 

[ryandias]

Ok, Not sure I stated the problem propperly.

The plastic body that the roll pin gets pushed into has a smaller diameter hole then the OD of the Roll pin.

I am trying to see the stress in the plastic eventually. But to get there, I need to figure out a way to approximate the force the roll pin exerts on the plastic body when it is inserted.

I think the only thing I can measure is an approximate diameter of the spring pin when inserted. Use this to approximate the force the pastic sees.

I am not sure how to get a "spring force" from the JIS B2808 or Strength rating of 70 (what unit that is?).

 

[CoryPad]

For the stress calculation, you could use a press fit equation, but you would need the stiffness of the pin. Contact the pin manufacturer.

JIS K 6301 is a standard describing mechanical testing methods. I believe the Strength Firmness is the double shear strength of the pin in kg_f/cm².

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[ryandias]

Thanks.