sticky transmission clutch

My Mazak M4 lathe has a 16 speed transmission and constant speed AC motor. Speeds 1-8 are accomplished by having clutch LL engaged and HH out. 9 to 16 just the opposite. Speeds 1-4 and 9-12 have a L clutch engaged and an H clutch disengaged. Again, just the opposite for speeds 5-8 and 13-16. Each clutch has a 24 Volt DC solenoid to bring it in.

Anyway, my L clutch is slow to disengage. Shifting from gears 4 to 5 (3 to 8 etc etc) momentarily locks up the tranny - NOT good. I added a 1 second delay anytime I drop clutch L before bringing in clutch H and things work fine. Except, now I don't have enough motor torque to shift to gear 13 because the spindle coasts down too much in speed during that one second. (Motor torque goes to red line, smoke comes out, and it smells like ozone so I hit the E-Z Stop)

I know its a long shot, but is there anything to do for a sticking drive clutch short of tearing the transmission down?

Karl

Reply to
Karl Townsend
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Karl,

Suggest first isolate the solenoid valve that actuates that particular clutch servo and try and clean it (or swap it out with one of the others from that same manifold block that's known to be good)...it sounds like a good possibility the valve could simply be clogged....

Oftentimes, they valves can get sticky from sitting in dis-use for some extended period of time where evaporation has left moving parts in the system dry--this particularily if portions of the circuit had been left open for a while and some dirt or crud got in there...usually, you can manually toggle the valve by poking an allen wrench into the recess at the center of the solenoid.....

Also, check your system pressure--if the pressure is too high or low, then sometimes your 2 way valves cant shuttle the valve spool into both positions reliably...

Once you do get it running right, suggest let just the hydraulic pump run for 24 hours or even longer (without actually running the machine)........this serves to allow enough time for more thorough filtration to occur...as it's not realistic to expect all contaminants to be trapped on a single pass-through....

Reply to
PrecisionMachinisT

Well....MAYBE...he's on the right track.....

Nope...I guess not...

Probly it's leaking at least a little--then again, doubtful that's related to the problem at hand...

Can you explain why you would think that might be something he should be considering ???

Perhaps a fresh bucket of hydraulic fluid is in order ???

Hmmm....sounds likely to me like this particular machine is nearly 30 years old....and my bets that Mazak ain't even gonna give him the time of day in Tokyo.

Hint--See:

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Reply to
PrecisionMachinisT

Cliff,

(Silly me) !!!

From his post, I get the impression one of his clutches is sticking--and in my experience, glazed friction linings tend to slip rather than stick.

Also, I dont know whether transmission fluid would help to deglaze clutch linings...

Do you ?

Reply to
PrecisionMachinisT

Cliff,

I was just pulling your chain is all...

And to Karl :

Appreciate if you let us know what you find out.

Reply to
PrecisionMachinisT

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