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How to calculate the compression of o-ring.

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socolp86

Mechanical
Joined
Feb 22, 2012
Messages
6
Location
HK
The o-ring is on the stem, after test, I found the stem has abrasion with the shaft housing. There are two aspects,first to modify the clearance of stem and shaft housing(match the o-ring's OD), second to modify the groove on the stem9match the o-ring's ID). The two methods all change the compression of o-ring,how to do it? thanks a lot.

What's your plan, How to do, What do you receive after review.
 


Good suppliers of O-rings will be able to advice you on all aspects:
form and size of groove and suitable O-ring form and size and materieal.

All technical data must be available.

If you are a producer one method might be to ask two competitors for technical advice, preliminary (not final!) offer to qualify for bidding, based on a number for tests and a presumed number per year.

 
Get manufacturer catalogs since many of these catalogs have engineering and technical data, sketches etc...
 
Like Parker O-ring Handbook. See section on rotary seal.

What is the purpose of the o-ring?

Ted
 
Ok,thanks for the advices, but on the Parker handbook, it defined the compression very simple(10%-20%). When the o-ring assemble on the stem(with groove), it's inner diameter first to largen. Then, take the stem into the shaft housing, the clearance between the stem and shaft housing control the o-ring's compression of OD. What should I do , to change the groove for ID or to change the clearance for OD?
The o-ring is motive seal, and I want to reduce the friction by the two methods metioned earlier.

What's your plan, How to do, What do you receive after review.
 
Reduce the groove diameter to reduce the stretch of the o-ring. This will reduce the squeeze(compression) and reduce the Joule effect that causes the o-ring to shrink onto the gland ID due to heating. Squeeze can be 0 to 8%. Keep the clearance you have in order to maintain extrusion resistance.

Ted
 
Thanks a lot for all of your comments.

What's your plan, How to do, What do you receive after review.
 
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