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Looking for (automotive?) servo to actuate a throttle

S

Scott Kelley

Jan 1, 1970
0
I need a fairly heavy duty servo unit (Stepper, or DC with feedback) to
operate the throttle on an
engine.

The catch is that it must have to have an electrically operated clutch to
allow it to be fully disconnected.

I can imagine that there may be some automotive cruise control units that
would work, but I am not at all familiar with what is out there. Any
thoughts?

Thx
Scott Kelley
 
J

Jasen Betts

Jan 1, 1970
0
I need a fairly heavy duty servo unit (Stepper, or DC with feedback) to
operate the throttle on an
engine.

The catch is that it must have to have an electrically operated clutch to
allow it to be fully disconnected.

I can imagine that there may be some automotive cruise control units that
would work, but I am not at all familiar with what is out there. Any
thoughts?

I think most cruise control units only push on the throttle lever
and when they "disconnect" they leave just back off and leave the
throttle under the control of the pedal.

maybe you could do the same?

. . . . . . . . . . . . .

rest/ilde
return spring (optional)
||///////////////|#
manual control-------------+
|><|------------------ to throttle butterfly
|
servo control -------------|><||//////////////|#
throttle return spring


. . . . . . . . . . . . .

manual control operated
return spring (optional)
||///////|#
manual control---------------------+
|><|---------- to throttle butterfly
|
servo control -------------|> <||//////|#
throttle return spring


. . . . . . . . . . . . .

servo operated
return spring (optional)
||///////////////|#
manual control-------------+
|> <|---------- to throttle butterfly
|
servo control ---------------------|><||//////|#
throttle return spring


. . . . . . . . . . . . .


the throttle rreturn spring is a light duty spring just sufficient to close
the throttle, this means that only a small servo is needed to oppose the
spring. the return spring for the manual control is onlt needed to pullt
the throttle cable, lift the pedal etc, if you're intending some other sort
of manual control it's not needed.


on the other hand stepper motors have only low torque when not powered
maybe the torque would be low enough so as not to need to de-clutch it.

a stepper motor with electromagnet field (instead of permanent magnet) has
no torque when not powered, I'm not sure of their availability
a selsyn type actuator could be possibly be used here but fed with a DC field
instead of AC and treated as a 3-phase stepper.


Bye.
Jasen
 
J

John

Jan 1, 1970
0
I need a fairly heavy duty servo unit (Stepper, or DC with feedback) to
operate the throttle on an
engine.

The catch is that it must have to have an electrically operated clutch to
allow it to be fully disconnected.

I can imagine that there may be some automotive cruise control units that
would work, but I am not at all familiar with what is out there. Any
thoughts?

Thx
Scott Kelley

Many cruise control units have a vacuum servo to move the throttle.
If you want a true clutch mechanism, perhaps a magnetic clutch would
work - it only provides a connection when energized.
John
 
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