So we're building some rubber tracked off road trucks and we're trying to decide which pumps and motors to use for the hydrostatic drives. I'm looking for opinions pro or con concerning Sauer-Danfoss H1 pumps and motors, Rexroth A6VM motors, 63 series and the new 71 series, and the AA4VG pumps. In the past we successfully used the Sauer 90 series pumps and 51 series motors, but it seems that these are soon to be discontinued. They wouldn't even quote me the 51 motors. On a related subject, we're most likely going to be controlling everything with Parker IQAN controllers and software, just to get the big three all in the same machine. :cool2
Have you heard of Brevini/SamHydraulic motors? I have been using them without issue for years. They offer reducers too. Looks like an Awesome endeavor you have there. Keep us updated.
My first choice would be the series 90's , simple and bulletproof and easy to repair. Secong would be the rexroth,as they are becoming more and more common for oem.
Thanks for the help, I appreciate it. Real world experience beats hell out of a spec sheet any day! We did look at the Brevini motors, and the planetary drives. The motors were more expensive (this may be due to my local distributor) than either Sauer or Rexroth. The only quote that was higher was Parker, no surprise there. For the final drives we have looked at Fairfield, Auburn, and Eskridge in the US, and Brevini, Carraro/O&K, etc. Working with Rexroth now, we'll see what they come back with. My first choice would be O&K but like all of them they're hard to deal with and are very expensive with high minimum order requirements and long lead times. Okay for big OEMs maybe but us little guys can't wait six months to a year for a pair of drives.
Thanks for your help. I agree, I like the Series 90 pumps, have had good luck with them. Don't know if the H1's have been out long enough to get any real track record yet. We did have an issue with the tandems we used in some smaller units, but they figured that out and corrected it very quickly. One other option, kinda crazy, I can get the European built 20 series pumps. They may not be the latest technology but in my experience they are tough as hell and last a long time, given minimal maintenance of the hydraulic oil and filters. Thoughts? LOL
For me, in the western US, Danfoss sales support is much better than Rexroth. I'd go with whoever can get you (and by extension, the owners of your equipment) parts the fastest. Fast parts will beat the best parts... second best today usually wins.
Will the setup be open loop or closed loop? If open, you'll need a manifold with counterbalance valves on the motor, and there is a great company in Portland called Hydra Power System (HPS) that can do that for you.
Closed loop. For something like an excavator or track drill it makes sense to go open loop, since travelling is usually a small percentage of the duty cycle. These machines are like trucks, their mission in life is to haul in cycles or continuously for long periods of time, so we use closed loop hydrostatic drive. No counterbalance valves here, too much heat. I have dealt with HPS several times over a period of years and always found them to be very helpful. Thanks!