Shaft Deflection
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Posted by: Vizsla_21 ® 02/10/2009, 14:26:32 Author Profile eMail author Edit

My son needs to figure out how much a shaft will deflect and i do not know how to show him. The attached shows a horizontal 25mm shaft with a cam plate attached. There will be 1000 pounds of force on the cam through the vertical shaft. The cam plate is 38mm from the bearing. Can someone provide a formula showing how to calculate the deflection?

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: Shaft Deflection
: Shaft Deflection -- Vizsla_21	Post Reply	Top of thread	Engineering Forum

Posted by: Kelly Bramble ® 02/12/2009, 08:38:42 Author Profile eMail author Edit

Well, you will need the following. 1) The applied compression force given by the spring at full compression. 2) Material /properties characteristics of the shaft (Modulus of Elasticity). 3) Section Modulas of the Shaft (Moment of Inertia)/(Distance from Neutral Axis to extreme fiber) simply center of shaft to outside diameter 4) Proper strength/deflection assumptions about the associated structure. Assume it is perfect? This is academia you know. Use the equations on this web page to calculate deflection --> Beam Deflection (/beam_bending/beam_bending9.htm). In engineering we call this "Stress Guessing" - humor fellow engineers - humor If this mechanism is already built take a dial indicator and mount it where you need to measure the deflection and zero out the gage without any applied spring/cam load. Then apply the full spring-cam load and observe the TIR (Total indicator Reading).

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: : Shaft Deflection
: : Shaft Deflection -- Kelly Bramble	Post Reply	Top of thread	Engineering Forum

Posted by: Kelly Bramble ® 02/12/2009, 08:43:53 Author Profile eMail author Edit

It looks like the cam is held in place by a a split ring clamp? I'm sure this works well, however I probably would have used a shear pin or shaft key way design of some sort. Other solutions are a matching flat on the shaft and cam. Just personal preference. What does this mechanism officially do anyway?

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: Shaft Deflection
: Shaft Deflection -- Vizsla_21	Post Reply	Top of thread	Engineering Forum

Posted by: zekeman ® 02/11/2009, 19:22:42 Author Profile eMail author Edit

Is this your son's homework? If so, let him got o his professor. If not, then where is the application? To do the problem you must specify how the shaft is supported at both ends.

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: : Shaft Deflection
: : Shaft Deflection -- zekeman	Post Reply	Top of thread	Engineering Forum

Posted by: randykimball ® 02/12/2009, 08:49:21 Author Profile eMail author Edit

Also, I'd design an extension on the bearing housing which extends out towards the cam and supports it as near to the cam face as allowable. You may could place the spring and keeper farther up the quill to allow for this change. If this design is for a auto-hammer you aren't going to be happy with the results. The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them. Modified by randykimball at Thu, Feb 12, 2009, 08:53:05

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