trying to grasp ratios in general
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Posted by: bobthedog ® 04/18/2007, 08:34:48 Author Profile eMail author Edit

Basically am getting abit confused with the scales and ratios. One gearing problem had was pinion has minimum number of teeth is 19 and the maximum number of teeth on a wheel is 150 and the velocity ratio is 8:1 so that is 19 x 8 isnt it like someone pointed out to us earlier which is 152 but it says that it should be limited or restricted to 6:1 so thats like 19 x 6 which is 114 teeth. The next bit is between ratio and scales if a scale on a map is in mm and the scale ratio is 1:2 that is a half scale right? For every one mm on the map is two of the actal value in cms meters or yards etc on the object. So thats a reduced scale an inlarged scale would be 3:1 etc for every 3 mm on drawing is one unit of value yards meters cms of object drawn. Just picked up a dvd and it has 4:2 display ratio so regarding that would would that mean. What is an equation or quickiest way to work out the velocity ratio of two gears meshing nothing more> THanks again. DONT GIVE UP THE FAITH

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Re: trying to grasp ratios in general
Re: trying to grasp ratios in general -- bobthedog	Post Reply	Top of thread	Forum

Posted by: bobthedog ® 04/18/2007, 08:40:52 Author Profile eMail author Edit

Ok realise that material boy gave us an equation for v ratios in meshing gears but it dont make sense because r1 is radius one T is tip V is velocity V ( 15 TEETH) 2xpixr1/T Now material boy put 7.5+tip but in the displayed equation it has / as in divided by tip so which is it please? DONT GIVE UP THE FAITH

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Re: Re: trying to grasp ratios in general
Re: Re: trying to grasp ratios in general -- bobthedog	Post Reply	Top of thread	Forum

Posted by: randykimball ® 04/18/2007, 09:59:58 Author Profile eMail author Edit

Just divide the number of teeth on the little gear into the number of teeth on the big gear.. forget everything else. For example: A 15 tooth little gear, driving a 45 tooth big gear. 45/15=3 ... the ratio is 3 to 1 No matter the diameters, teeth drive teeth! 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 Wed, Apr 18, 2007, 10:02:46

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Re: Re: Re: trying to grasp ratios in general
Re: Re: Re: trying to grasp ratios in general -- randykimball	Post Reply	Top of thread	Forum

Posted by: bobthedog ® 04/18/2007, 11:15:19 Author Profile eMail author Edit

Thanks randy that made it alot clearer just got confused. Can be a bit much sometimes thats all. DONT GIVE UP THE FAITH

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why 3;1
Re: Re: Re: Re: trying to grasp ratios in general -- bobthedog	Post Reply	Top of thread	Forum

Posted by: bobthedog ® 04/18/2007, 11:20:01 Author Profile eMail author Edit

3;1 ratio because the wheel with 45 times travels 3 x the rpm of the pinion right???? DONT GIVE UP THE FAITH

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Re: why 3;1
Re: why 3;1 -- bobthedog	Post Reply	Top of thread	Forum

Posted by: randykimball ® 04/18/2007, 22:19:03 Author Profile eMail author Edit

No, because the little gear turns around three times to one time of the bigger gear... 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.

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right got that thanks
Re: Re: why 3;1 -- randykimball	Post Reply	Top of thread	Forum

Posted by: bobthedog ® 04/19/2007, 06:56:08 Author Profile eMail author Edit

thanks again for clearing that up DONT GIVE UP THE FAITH

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