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

On Mon, 23 May 2005 14:38:05 GMT, "Karl Townsend"
remove .NOT to reply wrote:

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

Sounds like someone has not been maintaining the fluid, if it's
a fluid clutch. Is it? Oil leaking?

Can you use an automotive-type transmission fluid & a
few changes? Are they any cleaning fluids for such?
What does Mazak say?
--
Cliff

"Karl Townsend" remove .NOT to reply wrote
in message ink.net...
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,

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....

--

SVL

"Cliff" wrote in message
...

Sounds like someone has not been maintaining the fluid, if it's
a fluid clutch.

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

Is it?

Nope...I guess not...

Oil leaking?

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

Can you use an automotive-type transmission fluid & a
few changes?

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

Are they any cleaning fluids for such?

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

What does Mazak say?

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:

http://www.mazak.com/japanese/index.html

G

--

SVL

On Mon, 23 May 2005 23:25:29 -0700, "PrecisionMachinisT"
wrote:

Can you use an automotive-type transmission fluid & a
few changes?

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

IF the clutches were fluid clutches or bathed in the transmission
fluid (gearbox oil) they might have become "glazed" if the fluid level
became low or they were slipping, right?

Are they any cleaning fluids for such?

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

Would that deglaze any such clutches?

What does Mazak say?

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.

They might have some ideas at the local office .....
--
Cliff

"Cliff" wrote in message
...
On Mon, 23 May 2005 23:25:29 -0700, "PrecisionMachinisT"
wrote:

Can you use an automotive-type transmission fluid & a
few changes?

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

IF the clutches were fluid clutches or bathed in the transmission
fluid (gearbox oil) they might have become "glazed" if the fluid level
became low or they were slipping, right?

Are they any cleaning fluids for such?

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

Would that deglaze any such clutches?

What does Mazak say?

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.

They might have some ideas at the local office .....



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 ?

--

SVL

On Tue, 24 May 2005 12:21:49 -0700, "PrecisionMachinisT"
wrote:

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.

Glazed & gummed .... might have to turn the force up to
them then to not slip ....

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

Do you ?

Nope. A guess .... but it might just contain detergents &
suclike to clean such up a bit .... where's BB?

So I also suggested contacting Mazak service .....
--
Cliff

"Cliff" wrote in message
...
On Tue, 24 May 2005 12:21:49 -0700, "PrecisionMachinisT"
wrote:

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.

Glazed & gummed .... might have to turn the force up to
them then to not slip ....

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

Do you ?

Nope. A guess .... but it might just contain detergents &
suclike to clean such up a bit .... where's BB?

So I also suggested contacting Mazak service .....


Cliff,

I was just pulling your chain is all...


And to Karl :

Appreciate if you let us know what you find out.

--

SVL