MolaKule
Staff member
Here is an interesting question:
Regarding automatic transmission operation,
explain Drag Torque.
Regarding automatic transmission operation,
explain Drag Torque.
Automatic Transmissions - Drag Torque
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I have a great definition for "torque" but I can't share it here. As for the "drag" variety, I will have to give that some thought.
MolaKule
Staff member
Hint:
Think in terms of what happens inside the clutch packs during shifting or when in neutral.
Think in terms of what happens inside the clutch packs during shifting or when in neutral.
MolaKule
Staff member
Ok, you guys are getting warmer.
Look at this:
http://auto.howstuffworks.com/automatic-transmission1.htm
and this,
http://auto.howstuffworks.com/automatic-transmission11.htm
Now the clutches when disengaged are separated by a very short distance, but fluid flows radially from the center shaft to the outer edges of the clutches.
Fluid is flowing from the center to outer edges of the clutch assembly, and clutch and pressure plate are usually turning at different speeds.
What's happening to the fluid between the plates? Another hint, think what happens in the torque convertor?
Look at this:
http://auto.howstuffworks.com/automatic-transmission1.htm
and this,
http://auto.howstuffworks.com/automatic-transmission11.htm
Now the clutches when disengaged are separated by a very short distance, but fluid flows radially from the center shaft to the outer edges of the clutches.
Fluid is flowing from the center to outer edges of the clutch assembly, and clutch and pressure plate are usually turning at different speeds.
What's happening to the fluid between the plates? Another hint, think what happens in the torque convertor?
Let's see...drag torque...quote:
Originally posted by rugerman1:
Viscous Coupling?I'm a clutch guy
Is it when you have "viscous coupling" with a drag queen?
Sorry......
Actually, here is my guess: drag torque is the inertial momentum contained in the moving or recripocal parts, such as flywheels, freewheels and band brakes.
This phenomenom is what causes you to decelerate even if operating at a constant speed. In other words, it is the opposite of torque.
Yes?
Bob W.
MolaKule
Staff member
Hirev is on top of it. Good answer.
Anytime you have a spinning disk in fluid, the spinning disk imparts angular momentum to the fluid.
This angular momentum can be thought of as torque. This torque in turn imparts angular momentum to another clutch that may be spinning or turning at a different rpm.
There will be a drag torque induced in the fluid because of the differences in RPM between the rotating surfaces. This drag torque will raise the temperature of the ATF fluid and this Delta T has been measured.
This is similar to a torque converter in which there are differences in rpm between the driving and driven members of the TC.
Anytime you have a spinning disk in fluid, the spinning disk imparts angular momentum to the fluid.
This angular momentum can be thought of as torque. This torque in turn imparts angular momentum to another clutch that may be spinning or turning at a different rpm.
There will be a drag torque induced in the fluid because of the differences in RPM between the rotating surfaces. This drag torque will raise the temperature of the ATF fluid and this Delta T has been measured.
This is similar to a torque converter in which there are differences in rpm between the driving and driven members of the TC.
Both of my 1980's Suzuki GS bikes will turn their back wheels while idling in neutral. The back wheels are off of the ground due to the centre stand so it is easy to notice.
Steve
Steve
Kestas
Staff member
I too noticed this when I ran my car in neutral with the wheels off the ground. It's not a hard spin... I could stop the tire from rotating with my hand.
MolaKule
Staff member
Kestas, you just described Torque Drag. Good Example.
MolaKule
Staff member
Around here, we call it: Sympathetic, Incidental, Fluid coupling, of non Latent Viscous materials.
Or, SYFLOUS, for short.
{Don't get crabby with me about this!}
Or, SYFLOUS, for short.
{Don't get crabby with me about this!}
The manual for my Maybach (5 speed automatic) states that the car should never be shifted into neutral while moving. Why is that hazardous?
aehaas
aehaas
There may be a lockout that prevents the transmission from going back into gear until the car stops. If you try it, do it at low speed on a street with no traffic.
Mechtech, I think someone their has a dark sense of humor! You can cure "SYFLOUS" with antibiotic!! Their is no cure for a dark sense of humor! That is almost British!
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