Maybe but there's also the fact that the way he's talking about doing the fluid won't really be circulating. My instinct on this is that there's going to be localized hot spots. Especially at the cylinder which will have a lot of friction from the seals working this fast. If there was more circulation then the heat could be drawn off and dealt with easily.
Add this to the wear, leakage problems that you've already brought up (and I agree completely) makes me think that this is not going to be a good way of solving this particular problem.
Don Foreman wrote in news: snipped-for-privacy@4ax.com:
Yup, but they are only pulsed for short periods of time. Not a 24/5 operation, nor even an 8/5 operation. The other thing is...anti-lock brakes are mostly relieving pressure that has already been applied.
Air already does a bunch like clamps, wire advance, lock-outs and such. Actually, I think now after airing it out that we have the mechanical sollution perfected to the point of maturity. I'll know better after this second machine gets some experience and shows it's weeknesses. Number one went through some retrofits at the 6 month mark and has a
I've seen some hydraulic hammers and chisles that dont leak noticably after a year of hard use. I think Don's idea is worth trying, unless there is a better method available. I'd expect a routine maintenance schedule could provide a high degree of functioning time on Don's type system.
Not necessarily. I said I don't know -- they may be good for millions of operations between rebuilds. They might well outlast mechanical bushings,bearings and cams for all I know. It's certainly worth checking. Someone mentioned diesel injectors as one example.
He's talking about delivered power on the order of 130 watts or so. (Do the math.) Even if the system is only 50% efficient, which would be rather poor for hydraulics, that's less than 70 watts of heat to deal with. That should be a yawner.
Solenoids are terrible prime movers except in bang-bang apps, and even then they are very inefficient at producing significant motion. Tawk about heat! (Do the math)
Usual hydraulic experience is at much higher power levels -- tons of force, feet of motion, many horsepower. That's a whole different ballpark. Even a little inefficiency produces a lot of heat at those power levels. Experience is helpful only if it's relevant and applicable.
The cycle rate has nothing to do with wear rate or production of heat by friction. Those are functions of velocity, whether or not it's cyclic. 3/8" in 0.1 second is a velocity of 3.75 inches/sec, not exactly blinding speed.
Roller chains, sprockets, cams, bushings and bearings also wear. It is not at all obvious that a hydraulic system would wear any faster or even as fast as these components. That would have to be investigated to reach an informed opinion or conclusion.
Even if the desired motion is produced by cams, levers, chains and sprockets with bushings and bearings yada yada, long-lived reliable hydraulics might have a lot of value if it made those mechanical wear items more accessable and thus more easily maintained. That would certainly depend a lot on the application.
All that said, I sure don't argue with "if it ain't broke, don't fix it." One could surely learn a lot about hydraulics by trying it here, and that knowledge would very likely spawn viable new ideas for other applications even if it didn't work out here for some reason. But, at the end of the day, the name of the production game is goods out the door, not farting around with experiments.
Let the Asians waste their cheap time dinking around with new ideas, nyahhh!
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