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Author Topic: Pillow Block Problems  (Read 1296 times)

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Offline MastermimeTopic starter

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Pillow Block Problems
« on: June 18, 2012, 09:50:30 PM »
Hello everyone,

I've recently had a lot of frustration with pillow blocks.  Here are my issues

- The bearing comes out of place and is no longer fixed when I try pounding my axle difficult
- When I try to take out the axle, it is extremely difficult to pound out without a press
- There is a lot of friction when turning the axle connected to the bearing

These are issues I've had with the three pillow blocks I've ruined with the issues above.  If anyone has any suggestions on what I may be doing incorrectly, I'd be very grateful.

Thanks

Offline jkerns

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Re: Pillow Block Problems
« Reply #1 on: June 19, 2012, 08:37:14 AM »
Pounding is a good way to ruin bearings.

Do you have the proper fit between the bearing and the shaft? Is it too tight? That could be the reason for the friction. Or it just could be due to the pounding.

You want to press the axle into place using a vice and something like a piece of pipe or socket to press against the bearing.

Or, use a bearing with a set screw that doesn't require a press fit.
I get paid to play with robots - can't beat that with a stick.

http://www.ltu.edu/engineering/mechanical/bachelor-science-robotics-engineering.asp

Offline MastermimeTopic starter

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Re: Pillow Block Problems
« Reply #2 on: June 19, 2012, 10:20:33 AM »
Yes, I have the proper fit. 5/8" bearing and 5/8" axle.  My vise cant extend out 14 inches (length of axle + approximate width of pillow block).

Pounding it with a hammer is probably the wrong way to do it.  It was my only option besides taking it to my brothers shop to get it pressed.

The bearings I have do have set screws, but it is still very difficult.

Thanks for the response

Offline MastermimeTopic starter

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Re: Pillow Block Problems
« Reply #3 on: July 19, 2012, 02:05:23 PM »
Ok I bought a new pillow block and I'm still having issues.  Does anyone have any methods of pressing this?

Thanks

Offline waltr

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Re: Pillow Block Problems
« Reply #4 on: July 29, 2012, 12:35:01 PM »
Quote
Yes, I have the proper fit. 5/8" bearing and 5/8" axle.
Those dimension are not accurate enough to determine a proper fit. Use a micrometer and measure the shaft to better than 0.001 inch. The bearing should have specs of the ID from the manufacture.

A press fit should have only a very small interference (shaft larger than the bearing ID to Zero interference.
Google "press fit shaft tolerance" for detailed info on the proper fits.

Bearings normally do NOT like impacts and hammering on a shaft is a good way to destroy the bearings. Also the bearings themselves (balls or rollers between the inner and outer races) are not normally designed for axial loads (in the direction parallel to the shaft). Therefore, the inner race must be properly supported when pressing a shaft into a bearing.

Offline Soeren

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Re: Pillow Block Problems
« Reply #5 on: July 30, 2012, 04:43:34 PM »
Hi,

Perhaps the hammer struck the axle ends and whacked them out of shape a little?
Ask your brother to turn it to a better fit, if there's a lathe in his shop.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline MastermimeTopic starter

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Re: Pillow Block Problems
« Reply #6 on: August 03, 2012, 06:30:07 PM »
Thank you for the advice everyone.  Using a hammer initially was a mistake.  I received some advice from my friend.  He told me to sand off a couple thousandths of an inch off with emery cloth and then use WD-40 (lubricant) to lubricate the inside of the bearing.

I'll report back with the results

Offline Robot Attack

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Re: Pillow Block Problems
« Reply #7 on: August 09, 2012, 12:58:14 PM »
You can also try freezing the shaft to temporarily shrink its diameter before installing it

 


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