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Radial, Angular Contact, or ?? Smile
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Posted by: Waynger

04/01/2007, 17:55:40

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I am working on a rotating draw tube that will be supported by a non-rotating housing. Thrust loads will average 500 - 1000 pounds in both directions, radial load is minimal, probably around 50 pounds. Speeds are between 2000 - 3500 RPM. Built a prototype using a 6209 ball bearing but builds a fair amount of heat and a tremendous amount of drag. I am going to disassemble it to make sure that there isn't some other problem but I think it's the bearing generating the drag. I looked to the radial ball bearing first because of the ease of sealing and the fact that I use them frequently. Is there a rule of thumb as far as how much thrust a ball bearing can take, like a percentage of its load rating?

I welcome any suggestions, Wayne








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Re: Radial, Angular Contact, or ??
Re: Radial, Angular Contact, or ?? -- Waynger Post Reply Top of thread Forum
Posted by: jboggs

04/02/2007, 18:39:51

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The bearing manufacturer could answer your question best. Call them. A 1000 lb thrust load and a 50 lb radial load? That says "use a thrust bearing" to me. Not surprised your plain ball bearing is overloaded. Any good bearing catalog could answer your question.







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Re: Radial, Angular Contact, or ??
Re: Radial, Angular Contact, or ?? -- Waynger Post Reply Top of thread Forum
Posted by: Kelly Bramble

04/01/2007, 21:09:40

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There should be performance and application specifications available from the manufacturer for your particular bearing. Else. just contact your favorite bearing company, provide them with the performance you require, and thier application engineer will recommend a bearing.






Modified by Kelly Bramble at Sun, Apr 01, 2007, 21:10:28


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Re: Re: Radial, Angular Contact, or ??
Re: Re: Radial, Angular Contact, or ?? -- Kelly Bramble Post Reply Top of thread Forum
Posted by: randykimball
Barney
04/02/2007, 00:06:27

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Generally if you have very much thrust on a standard ball bearing it will shorten its life and generate more heat as you force it out of center and into a deeper load as it tries to ride up towards the edge of the outer bearing race groove. If you need much vector it this direction you should shift to the 7209 (check that number to be sure). The 7200 series is intended to take vector forces. One side of the each race will have a deeper race shoulder. You must be sure to apply this bearing with the deeper race shoulders in the proper direction to accept the vectored forces. However there is a price to pay (pun intended) the 7200 series is considerable more expensive. An other method is to include less costly needle thrust bearings into the assembly to handle the thrust forces.




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Modified by randykimball at Mon, Apr 02, 2007, 00:07:55


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Re: Re: Re: Radial, Angular Contact, or ??
Re: Re: Re: Radial, Angular Contact, or ?? -- randykimball Post Reply Top of thread Forum
Posted by: Waynger

04/02/2007, 19:15:40

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Thanks to everyone for all the input! I am going to try a double-row angular contact (5208ZZ)(bidirectional thrust) reacting against a ball thrust (single thrust direction) on the other end. Needle bearings were interesting but they wanted a heat treated area if the cage were to touch plus they weren't banded. One bearing co said thrust could be 30 - 50 percent of load rating I'm currently at 20 percent on my radial bearing setup put I have very limited horsepower and heat dissipation available. Hopefully the 5208ZZ will result in lower drag. I give this setup a 70 percent chance of working we will see..

Thanks Wayne








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Re: Re: Re: Re: Radial, Angular Contact, or ?? Smile
Re: Re: Re: Re: Radial, Angular Contact, or ?? -- Waynger Post Reply Top of thread Forum
Posted by: AdrianT

04/04/2007, 02:37:43

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See if you can get some low friction seals. Many bearings have this option. Phone up a company like SKF, or e-mail them, and they'll send you their general catalogue free of charge. This will help quite a bit and give you a better understanding of what the limitations and applications of the respective bearings are.

Cheers
Adrian








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