Design and Engineering Forum Forum Moderators: randykimball, Administrator | POSTING POLICY / RULES | How to post an Image
 torque to linear force conversion/formula Post Reply Forum
 Posted by: jaqlynne ® 11/02/2006, 12:35:14 Author Profile eMail author Edit I need to convert a torque moment to linear force. I do not know the formula, nor can I come up with one.Here is the scenario - I need to come up with a half shaft (Drive shaft) to transmission pull out test that an operator can perform on the line with a torque wrench (not a pry-type motion).The linear pull-out test force is 45 lbs - 100lbs. I am presented with nice (almost custom fit) groves on the half shaft. I want to take a torque wrench with a 'horseshoe' type of bracket to put into the grove. What torque value will I need to see on the torque wrench to give me 45 lbs - 100lbs linear pull out force?

 Replies to this message

 Re: torque to linear force conversion/formula Re: torque to linear force conversion/formula -- jaqlynne Post Reply Top of thread Forum
 Posted by: garyfowler ® 06/06/2007, 14:54:43 Author Profile eMail author Edit I found a WEB based calculator that may help/calculators/torque_calc.htm

 Re: torque to linear force conversion/formula Re: torque to linear force conversion/formula -- jaqlynne Post Reply Top of thread Forum
 Posted by: Zip ® 11/21/2006, 00:26:41 Author Profile eMail author Edit May I enquire why a torque wrench? Maybe an air cylinder with the required piston area,pressure and stroke. Throw in a couple of limit switches possible? Zip

 Re: torque to linear force conversion/formula Re: torque to linear force conversion/formula -- jaqlynne Post Reply Top of thread Forum
 Posted by: RBPrice ® 11/02/2006, 13:25:29 Author Profile eMail author Edit Hello Jaqlynne - let's see if I understand your situation: you have a splined shaft that has to pass an axial load test of 45 to 100 lbs. You want to somehow covert rotary motion to linear motion so that a technician/assembler can verify the force required to move the shaft.Well, the simplest form of rotary to linear motion is a screw and if you use a ball screw you will have minimized friction so that the torque reading will have a reasonable relationship to the axial force created by the torque. You will need to make an adapter that clamps to the shaft, attach the ball screw to the adapter and then the torque wrench to the end of the screw which, of course, will need to be supported somehow. You can calibrate the thing by first measuring the force needed to make the shaft move using a simple spring scale.Hope this is of some help.

 Re: Re: torque to linear force conversion/formula Re: Re: torque to linear force conversion/formula -- RBPrice Post Reply Top of thread Forum
 Posted by: jaqlynne ® 11/02/2006, 13:46:08 Author Profile eMail author Edit Thank you for your input, RB. I am affraid that I wasn't as clear as I could've been in my breif write up. What I should've made clear was the fact that I am not wanting to rotate the axle. Rather, think of it this way, image I had a large (very large) pair of vice-grips and I clamped them on to the outter case of the cv joint that has the spline shaft connected to it. Now imagine pulling along the major axis of symetry, as if to pull the half shaft out of the transmission. Having said that, replace the vice grip with a torque wrench with a horse shoe-style detail. I am not wanting to rotate the axle...rather, if exagerated, I would be tring to bend the splined shaft. Hopefully this is clearer. And I do appreciate your input. J

 Re: Re: Re: torque to linear force conversion/formula Re: Re: Re: torque to linear force conversion/formula -- jaqlynne Post Reply Top of thread Forum
 Posted by: RBPrice ® 11/06/2006, 10:44:15 Author Profile eMail author Edit J - nothing I described in my first post talked about rotating the shaft only pulling on it axially. If the shaft is part of a CV joint then obviously you will have to constrain the joint assembly so that you can pull axially on the shaft. You don't need a large pair of Vice Grips (capitalized since that is a Trade Marked name) but you will need some way to grip the OD of the splined shaft. Like a simple commercial split collar with the right ID. Pull on the collar with a calibrated spring to see if the splined shaft is retained in the CV assembly to the proper degree of tensile loading.

 Re: Re: Re: torque to linear force conversion/formula Re: Re: Re: torque to linear force conversion/formula -- jaqlynne Post Reply Top of thread Forum
 Posted by: stewart ® 11/02/2006, 14:39:00 Author Profile eMail author Edit HelloDivide torque reading by distance from shaft center to center of hand. You'll get different forces for different handle lengths and if wrench handle is not at 90 degress to shaft. Do you need a linear spring scale on shaft end, sounds like a better test?Stewart