A recent arrival on ‘Planet Brendan’ who works for Bosch Rexoth’s ‘Large Hydraulic Drives’ division in Sweden (a.k.a. Hagglunds division) wrote me this after reading my “6 Hydraulic Mistakes….” report:
“I would have liked more information on why you shouldn’t have filters on the drain line on piston pumps. We actually use that solution in our drive units and we … Read more
While absolutely essential on a piston-type hydraulic motor, an external case drain line is usually optional on gear motor designs–external, internal and gerotor/geroller. These types of motors don’t have a large-volume case or sump like piston motors do. But they do have internal leakage which by design, usually accumulates in a small cavity just behind the shaft seal.
By installing … Read more
In chapter 13 of The Hydraulic Maintenance Handbook, I discuss the principle of engineering out issues that have the potential to cause recurring maintenance problems. Since maintenance occurs after the event, that is, after the machine is designed and built, this strategy is very much a retrospective one. Which means it’s desirable and preferable not to engineer in such … Read more