Fun with physics. Math nerds needed - JeepForum.com

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post #1 of 18 Old 05-20-2016, 01:39 PM Thread Starter
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Fun with physics. Math nerds needed

Hello everyone, I'm working on a physics project for school and am trying to explain and calculate the forces present in a trac lok LSD. I mostly understand how it works I just need help with calculations. Found this website, could someone possibly help identify the variables on the straight bevel gears and help me calculate the forces present

https://www3.nd.edu/~manufact/FME_pd.../FME3_Ch15.pdf


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post #2 of 18 Old 05-20-2016, 02:06 PM
2jhanna
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Wow, good news, apparently I'm not nerd enough to be of any help to you.

Good luck.

jhanna
denton county, tx
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post #3 of 18 Old 05-20-2016, 02:22 PM
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That little PDF is just going to go into my archive...

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post #4 of 18 Old 05-20-2016, 02:32 PM Thread Starter
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Come on guys, the straight bevel gears is the easy part haha. I'm trying my best but I can't figure out sin of the angle, or what the angle is referencing
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post #5 of 18 Old 05-21-2016, 04:59 AM
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Originally Posted by 2jhanna View Post
Wow, good news, apparently I'm not nerd enough to be of any help to you.

Good luck.

Quote:
Originally Posted by mrblaine View Post
Springs have one job and one job only and it isn't to affect, determine, or create ride quality.
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post #6 of 18 Old 05-21-2016, 07:00 AM
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Maybe alpha is referencing the angle between the gear shafts? Later in the pdf, they mention they are only talking about right angle shafts, which might explain why an explanation of alpha is never given.

If that's the case Wr will always be 0 though, which doesn't seem right.

***edit***
Your pdf screwed up a letter. Alpha in the equation represents gamma in the diagram.

see page 9 of this:
https://eis.hu.edu.jo/ACUploads/10526/CH%2013.pdf
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post #7 of 18 Old 05-21-2016, 07:31 AM
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Originally Posted by mike_dippert View Post
Maybe alpha is referencing the angle between the gear shafts? Later in the pdf, they mention they are only talking about right angle shafts, which might explain why an explanation of alpha is never given.

If that's the case Wr will always be 0 though, which doesn't seem right.

***edit***
Your pdf screwed up a letter. Alpha in the equation represents gamma in the diagram.

see page 9 of this:
http://eis.hu.edu.jo/ACUploads/10526/CH%2013.pdf
Went straight over my head.
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Springs have one job and one job only and it isn't to affect, determine, or create ride quality.
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post #8 of 18 Old 05-21-2016, 07:36 AM
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I wish they would have taught math in a different manner in school and given some real world examples instead of just teaching formulas over and over. I took advanced math all through school but never went on to college, started in electronics straight out of school. Funny but now I have been knocking the cob webs out of my head doing probability calcs for safety instrument equipment systems. This gear stuff is fun....

So I take it Wt is the load the gear is capable of transmitting....I need to understand the difference between the term "load" and torque now......
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post #9 of 18 Old 05-21-2016, 08:11 AM
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I need to understand the difference between the term "load" and torque now......
load is normal to a surface...it's force pushing perpendicular to a plane. force is in units of lbs, kg or newtons. think about standing on a scale - gravity is pulling you perpendicular to the floor so your weight is the force you exert on the earth, in pounds.

torque is a rotational moment of force, or a "turning force" about an object. torque is in units of force times the length of the lever arm. think about tightening a lug nut. the force you apply to the lug nut is via a breaker bar or wrench - the torque is the force times the length of the bar. You if you apply 50 lbs with a 2 ft breaker bar, you have 100 ft-lbs of torque applied to the lug nut.

and no, i won't solve your gear problems for you. You're on your own - theres plenty of videos and tutorials online. I stumbled through this kind of stuff for 10+ years to get 3 degrees in engineering - if you want advise - just make a best guess and keep moving.
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post #10 of 18 Old 05-21-2016, 08:19 AM Thread Starter
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Ok, thanks that helps some. I'm trying to solve for the axial force. Any idea on how I could estimate the two angles in the example of spider gears and side gears inside of a trac lol differential? What is Wt and W representing and how do I find them
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post #11 of 18 Old 05-21-2016, 08:23 AM Thread Starter
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Just so everyone knows, I'm not trying to cheat or anything by asking for help to solve this. It's just an extra project for the end of the year and I thought it'd be cool if I could calculate some of the actual forces at play.
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post #12 of 18 Old 05-21-2016, 08:26 AM
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Just so everyone knows, I'm not trying to cheat or anything by asking for help to solve this. It's just an extra project for the end of the year and I thought it'd be cool if I could calculate some of the actual forces at play.
http://www.engineersedge.com/gear_formula.htm
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post #13 of 18 Old 05-21-2016, 08:35 AM Thread Starter
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Originally Posted by Unlimited04 View Post
Quote:
Originally Posted by Trevlaw View Post
Just so everyone knows, I'm not trying to cheat or anything by asking for help to solve this. It's just an extra project for the end of the year and I thought it'd be cool if I could calculate some of the actual forces at play.
http://www.engineersedge.com/gear_formula.htm
Thanks unlimited, I'm gonna have to spend some time looking through all this after work today
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post #14 of 18 Old 05-21-2016, 08:47 AM
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If you are trying to find Wt or the tangential force in that straight bevel gear diagram, you would just multiply by cos(phi) both sides and then the cosines cancel. You would be left with

Wt = T / r(avg)
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post #15 of 18 Old 05-21-2016, 11:33 AM
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Originally Posted by Unlimited04 View Post
load is normal to a surface...it's force pushing perpendicular to a plane. force is in units of lbs, kg or newtons. think about standing on a scale - gravity is pulling you perpendicular to the floor so your weight is the force you exert on the earth, in pounds.

torque is a rotational moment of force, or a "turning force" about an object. torque is in units of force times the length of the lever arm. think about tightening a lug nut. the force you apply to the lug nut is via a breaker bar or wrench - the torque is the force times the length of the bar. You if you apply 50 lbs with a 2 ft breaker bar, you have 100 ft-lbs of torque applied to the lug nut.

and no, i won't solve your gear problems for you. You're on your own - theres plenty of videos and tutorials online. I stumbled through this kind of stuff for 10+ years to get 3 degrees in engineering - if you want advise - just make a best guess and keep moving.
Thanks, I did some reading and figured it out, in my line of work, Load is in the electrical format, so I needed to change my line of thought.
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