Wrap Spring Clutch Lubrication 2

[jerryv]

Wrap Spring Clutch Lubrication

My company has been utilizing a wrap spring clutch on our braiding machine for over 20 years. Do to the discontinuation of the original Aeroshell 17 grease we have been forced to change to Aeroshell 33MS grease. The new grease is not performing as well as the old. The 33MS is separating during operation causing the customer to re - lubricate more frequently.

Can anyone provide an alternative for a wrap spring clutch?

Jerry
Reading PA

 

[TVP]

If this application requires aerospace approval, then Royco 64 from Anderol is the other grease approved to MIL-G-21164. Both of these use a diester base with additions of lithium stearate and MoS[/sub]2[/sub]. Dow Corning makes many different types of lubricants and greases containing MoS[/sub]2[/sub], but they do not this particular combination-- their offerings with a wide temperature range use a silicone base or a synthetic PAO oil, which means that they are likely to be considerably more expensive.

 

[jerryv]

TVP,

Our application does not requires aerospace approval.

Shell Lubrication recommended a non MIL spec grease ALVANIA® GREASE CG. Do you have any experience with this grease?

 

[tbuelna]

jerryv,

Spring wrap clutches are wonderful devices for torque limiting or overrunning. They are compact, simple and provide consistent release characteristics. Unlike other clutch devices like sprags or rollers, they do not experience high local contact stresses between the race and the clutching elements. So theoretically a spring wrap clutch should not require an EP additive grease like Aeroshell 17 or Aeroshell 33MS. You may wish to take a look at something like a wheel bearing grease (Aeroshell 22) that may prove to be more stable.

Here's an excellent technical reference on high-performance spring wrap clutch design:

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA047559&Location=U2&doc=GetTRDoc.pdf

Good luck,
Terry

 

[plasgears]

Plant Engineering Magazine had an annual interchangeable lubes issue. That might get you to first base.

 

[romke]

the royco grease and the aeroshell grease are/were identical. if the royco grease is readily available i would tell the customer to change over, avoiding experiments that do not necessarily guarantee a useful outcome.

there is a large difference both in baseoil viscosity and type of base oil used in the two aeroshell greases.

alvania cg as suggested has an even higher baseoil viscosity, that may add to the problems you already have. it is a specialized product for geared couplings - an application where centrifugal forces play a big role in separating oil and thickener. for those applications it is quite a suitable grease but in your case the problem will problably worsen.