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Nonmetallic wheel bearings

Nonmetallic wheel bearings

Nonmetallic wheel bearings

(OP)
Greetings, fellow engineers!
I am seeking advice for our application, which is a completely nonmetallic wagon carrying an electromagnetic transmitter/receiver system. The current wheel bearing assembly has failed. It consists of zirconia-toughened alumina (AZT) bushings (~ 4" long, inserted into the wheel rims) with a carbon-fiber-reinforced-polymer shaft (a thin-walled, 1" O.D. tube) as a fixed axle. Failure occurred when the bushing abraded the shaft enough to seize, causing the shaft to rotate and to break free of the restraints on the wheel housing. A field repair (cleaning and reassembly with liberal amounts of white lithium grease) lasted two days, until the shaft itself broke in two. The load on the wheel ~60 lb, nominal service speed ~1 rev/sec, short-term max. speed ~4 rev/sec. Any ideas (especially using other materials with the same bushing-bearing design approach) would be greatly appreciated.

RE: Nonmetallic wheel bearings

Make the bushings from wood.  Or use traditional laminated wood oxcart wheels.  Use lots of grease, and don't expect miracles wrt lifetime.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: Nonmetallic wheel bearings

(OP)
Thank you, MikeHalloran and unclesyd, for your quick replies. The woodexbearing.com web-site has hardwood bushings we can use.
Any suggestions for the non-rotating axle, which has to be 18 inches long and completely nonmetallic?

RE: Nonmetallic wheel bearings

What size is require ,dia and length ?

What type of loads?

RE: Nonmetallic wheel bearings

(OP)
Wheel bushing is zircon-toughened alumina, 4 inches in length.
The shaft has to be 1 inch O.D. and 18 inches long. The bearing (journal) surface is 4 inches. The shaft supports TWO wheels (side-by-side). A 4 inch long cylindrical spacer separates the bushings. The load on each wheel is 60 lb (120 lb total load on the shaft). Wheel rotation: 60 RPM steady operation; 180 RPM in short (10 sec) intervals.

RE: Nonmetallic wheel bearings

Here are few suggestions for your shaft.  You will have to take a look at your application to see which one is best suited. I tend to favor the Micarta as I've used it in many applications as both a bushing and shaft.
I would give each reference a call and discuss your problem, especially Norplx-Micarta as they have been extremely helpful in the past.

Carbon fiber the ultimate material.

http://www.bactechnologies.com/index.html

All the glass reinforced materials along with extruded unfilled material.plain.

http://www.calsakplastics.com/display_category_products.php?C
ategoryID=745

High strength:

http://www.norplex-micarta.com/products/29/TDB%20NP511B.pdf

Internal lubricant:

http://www.norplex-micarta.com/products/68/RM315_TDB.pdf




   

RE: Nonmetallic wheel bearings

(OP)
Hi, diskullman.
Early on, we tried plastic bearings (delrin with glass balls). Unfortunately, they failed when the balls shattered. I will check the website you posted...perhaps we can revisit this.

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