New problem with broom - lost hydraulics

[dstig1]

Here is what the shaft looks like currently. I welded adapters onto the end for the pump. Pump is at the bottom of this pic. This was before I welded up the coupler. There is a solid 3/4x7/8" shaft coming out of the U-join yoke. This is welded to a shaft adapter and then welded to a 7/8" x 13 Tooth spline adapter that the pump slides into. Splines seem to be a dark art corner of the machine part world. I have found an SAE B spline that I think is the same as this pump shaft but cannot find any confirmation that these 2 are actually the same as of yet. It should be a standard shaft.

You can see where the pump mounts and the spline coupler that is now stripped sits:

 

[Doaaj50]

First of all, I am glad to hear you tracked down the problem.

One phenomenon that occurs on shafts is fretting corrosions which can lead to a spline failure. I have seen this many times between mating shafts that have relative motion between them. A tell tale sign of this is you will find a reddish/brown powdery residue on the mating shafts.

You can greatly reduce that failure by applying molybdenum disulfide grease to the splines when they are assembled. Keeping it greased regularly is also recommended.

 

[mrmikey]

Wonder if it's lack of or no lubrication? When I had my Goldwing (I think it was) the service manual insisted on Moly paste. Apparently it works on the molecular level and actually deposits itself on the splines so it's not metal to metal wear?
Just looking at your pic. If I was a betting man I'd say shaft alignment, you'd only have to be of a couple of tho and the splines would be constantly working up and down. I think there should be a U joint between the last bearing and the pump. My thoughts would be to turn the shaft around so the U joint is at the pump and turf the last mount with the flange bearing. Just my opinion so take it for what it's worth

Just noticed Doaaj50 mentioned Moly grease also...I gotta learn to read all the post ;-)

 

[k2man]

Did you make your splines in the shaft yourself? Did you make the mating splined hole? How many splines (grooves)? To transfer power, more splines are generally better. Matching the shaft splines to the hole grooves is also critical. I didn’t see a photo of your shaft.

 

[ArlyA]

Interesting that the shaft or splines failed. I'm following this to see how.

 

[oldnslo]

Dave
SAE - B 7/8” 13 tooth 16/32 pitch is a standard spline. Does your pump have a tapped hole in the center of the shaft. Not sure if all companies add this feature. If yes this can be used to hold spline yokes onto the pump.

I agree with others in suspecting you need a U-joint on both ends of the shaft connecting to the pump.

Nice job on building that frame to mount every thing

 

[mrmikey]

Nice job on building that frame to mount every thing

I meant to add that also, very neat professional looking job

 

[Doaaj50]

Another alternative to a u-joint could be to install an elastomeric coupling between the pump and the bearing. As long as your misalignment between those two shafts isn’t significant, a coupling with an elastomeric center could work.

The other advantage of a coupling is that it is very configurable. You find one hub that matches your pump spline and the other that fits your stub shaft coming through that last bearing and then the elastomer connects the two together.

Lovejoy or Rexnord would be two coupling manufacturers that you could investigate further if you are interested in that path.

 

[mrmikey]

Another alternative to a u-joint could be to install an elastomeric coupling between the pump and the bearing

That's an even better alternative, or a chain coupling. I believe a Lovejoy is more forgiving tho:

 

[ArlyA]

That's an even better alternative, or a chain coupling. I believe a Lovejoy is more forgiving tho:
View attachment 775154
View attachment 775153

I like your solution.