Replacing needle bearing with a bushing

[duc916]

I am trying to replace a needle roller bearing (no dedicated inner and outer race per say, uses pin and outer housing for races) with a bushing. At this point I need to find a material I can machine myself to make the bushing. I have looked at Glacier Garlock LB9-machined bronze as a possible material, but the maximum dynamic load is too low 17,400 psi). I calculate the max dynamic load of my system to be 27,750 psi (1000 pounds / (0.2325" pin diameter x 0.155" pin length)).
The main reason I would like to replace the bearing is the motion on the bearing is oscillating, thus the bearing does not experience a full rotation. Thus the load side of the pin has a tendency wear. After many iterations we are still fighting material break down of the pin. The needle bearing manufactured actually suggested a bushing in this application.
So to make a long story short, can anyone tell me a direction of material selection for this problem? Thanks in advance for the help.

 

[israelkk]

What about the friction coefficient? The bushing friction coefficient is much higher than the needle roller bearing friction coefficient. Do you use a full complement needle roller bearing (without the cage) so there are many more needles to take the load?

 

[duc916]

We are using a 0.048" diameter roller, and we use a full complement without the cage. The coefficient of friction for the bearing starts out good, but as the pin wears it goes off the chart, so if the bushing can hold together the coeff. of friction should stay more constant.

 

[israelkk]

What is the size of the I.D. and O.D of the bearing?
The 0.048" roller you mean the diameter of the rollers inside the bearing?

What is the pin made off and what is it's strength/hardness?

 

[israelkk]

One more question:

What is the required life cycle of the pin-bearing couple?

 

[duc916]

The roller is the only part, by this I mean the roller rides on the pin (inner race) and the outer housing is the outer race (due to size restraints there is no room for a true inner and outer race). At this point we are done with the needle bearing. I am more interested in pursuring a bushing. The life cycle is a little over 1 million cycles. Thanks for the help.

 

[israelkk]

WhatI can suggest from my experience you can do it with a custom bushing made of a hard steel and using a dry lubricant. I have designed a lug assembly connection for a transfer of a pneumatic piston linear movement to rotational movement using a 5 mm diameter pin for piston force of 2500 lb. However, the design is a little bit tricky and kind of a commercial secret.

 

[EdStainless]

I hope that the load is not impact, and that motion is slow. If so, you might look at bearing bronzes such as C90700 or C91300.
The other thought is plate one of you members with electroles Ni and then age it to a high hardness. And plate the other componant with the bearing alloy. The thinner the bearing material the less deformation.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[unclesyd]

You might want to give these people a call. I used this material in similar applications.

http://www.metaltekint.com/Bearium/

 

[duc916]

EdStainless,
Of course it has shock loading and moves at a high rate (small oscillating motion); if it didn't my job would be no fun (insert smile). The shock loads vary in magnitude and are not easily measured or calculated, thus we have approximations of what they are. Are you concerned with the bushing getting "pounded out" (sorry for the lack of a better term)?

unclesyd,
Gave them a call and they are sending over technical specs, their website was not very technical from what I could find. Thanks for the heads up!

Thanks for all the help so far, it has got me somewhat optimistic about the feasibility of a bushing.

 

[mewhg]

Israelkk,

I know you mentioned that your design of a steel/steel pin/bushing is a trade secret but we would be interested in anything you could share.

thanks

 

[israelkk]

mewhg

Before I can respond to your last posting I will need to know more on your design to see if your case can be solved in a similar way. Is your case is a lug shape design. A drawing can help.

http://www.webspawner.com/users/israelkk/

 

[mewhg]

Israelkk,

I don't have a specific need but was just generally interested in your design i.e: selection of steel, hardness, tyoe of solid lube, etc.

My designs are mechanisms (lots of metal to metal sliding) and I am always keeping an eye out for methods (other than platings and coatings) to reduce friction and wear.

 

[EdDanzer]

A dynamic load of 27,750 psi exceeds the film strength of most petroleum based lubricants. This becomes a tough problem. There are coatings that may work to reduce friction. Do not use hardened steel against hardened steel unless some coating is used. Aluminum bronze may work if the velocity is not too high. P/V will determine what materials to use. The problem is there is very little dependable P/V information.