What Happens to a Fluid Coupler When it Gets Too Warm?
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- เผยแพร่เมื่อ 7 มี.ค. 2023
- Files: drive.google.com/drive/folder...
Hello again viewers. In response to comments suggesting new methods to test my fluid coupler, I went and conducted a few experiments with it. This video also helps explain how a fluid coupler and somewhat of how a torque converter works.
#3dprinting #engines #engineering #transmission - วิทยาศาสตร์และเทคโนโลยี
Dynamic torque the commenter was referring to is actually the torque while the shaft is spinning. Your torque tests were done with the coupler stalled against the little scale, this is known as static torque. A simple (and very similar to what you did) test for dynamic torque is a pony brake, you basically just let the lever arm slip on the coupler output so the coupler can actually spin.
Thank you for the clarity! If I had to guess it's dynamic torque increases as the oil flow becomes faster and smoother while the momentum of the oil helps keep things in motion
Very good video mate, tho im pretty sure those scales arent meant to have their range extended like this. While it works, it might break the load cell or other plastic components inside. Besides that, its probably not calibrated properly for loads higher than its range. If the load cell is rated for 500g, its output outside that range will be off by a significang amount. Your last test might actually be caused by a damaged load cell, check it with the steel ball again to see if it works. For future tests consider using a kitchen scale, these usually go up to 2/5 kg and have 1 gram accuracy. Plenty for tourqe testing.
Thank you! I actually just checked again, it seems to be reading accurately. I do wonder if maybe the accuracy begins to deviate more and more past 500g, it is possible that a larger scale will provide better accuracy
@@CamdenBowen also entirely possible they accounted for people doing something like this and used 1000 g cells and divided it in half to get the scale's advertised rating
I'm guessing the scale has 1 kg of range but it's halved for taring purposes
On the subject of a broken load cell
You could clearly see that the arm attached to the coupler was bouncing, and not staying put as expected, so even if the cell was broken, you wouldn't really be able to tell
if you want to make a 3d print watertight, one of the easiest ways is to just spray on some plastidip. the relatively rough surface of a 3d print makes it really easy for the plastidip to adhere to it. i did this when i made some custom hose adapters and it stayed completely dry on the outside where i sprayed on like 1 or 2 thin layers.
To reduce the chance of a leak, set the slicer's seam position to random (and increase the number of outer layers to as thick as practical)
The scale has a maximum because it needs to be able to return to it's original shape. Also when you overload it, it may not change it's resistance linearly in that range.
5:25 It works exactly the other way around, when arm isn't horizontal it's "shorter" so the scale will read more force.
Also, "dynamic torque" means torque while output shaft is spinning too.
fluid couplers are also used in industrial machinery, and they also have blow out plugs in case the load stalls the coupler, you could imagine what happens if left unattended without blowout plugs. it basically becomes a small hydraulic bomb that spews melting hot oil everywhere on failure.
Ive repaired a couple.
Very simple designs.
This coupler reminds me of submersible construction water pumps. They have mineral oil inside them to keep the water out and keep vacuum from forming as it heats and cools over time.
The centrifugal force of the oil being pushed out towards the outside shell as well as it heating up.
Fragmented sentence.
@@fetsgaming5740 So! dya have a problem with it?
incredible work! i am looking into implementing this on an rc car.
Thank you! I will provide the files in the description shortly!
Very interesting, thank you for this video
The layers delaminate probably because as the oil gets hot, it expands ever so slightly... FDM printing layer adhesion is probably never going to be good enough to counteract this. Although I suppose you could try some things like making the housing out of abs and acetone smoothing it (that would ideally create a continuous outer shell) or sintering - although I have heard that this actually makes the part weaker.
I had filled the coupler to about 75% or so to account for the thermal expansion. However as the oil warms up it becomes thinner and since it is also under pressure from the coupler running, it probably aided in forcing it through. Instead of using ABS and acetone to smooth it out, I may try annealing the parts to evenly melt all of the layers together. Though it raises concern for if the part tolerances will change after the process.
You could also cost your parts with epoxy or ca glue to fill in the layers
@@CamdenBowen I wouldn't mess with annealing plastic. Way too much deformation and guesswork, and your work requires low tolerances. If FDM doesn't work, you can try SLA, next best would be CNC alum for certain components
Hi there!
Great video!
I’d love to see you check the efficiency of the coupler at different loads, (meaning the output is spinning instead of being fixed and you could try to mesure how much energy is making it through the coupler, to figure out the efficiency)
Hope to see another one of your videos soon!
I've probably had ten sets of those scales, I'm so glad I left that life behind me lol
I'm somewhat interested to see how well that sort of fluid coupling works with different viscosities of fluid. Perhaps testing a range of viscosities from water to something thick like gear oil.
It would also be interesting to see how grains behaved, something like a very fine sand
You should make an rc tractor trailer with a flatbed to hold metal weights and add the fluid coupler to the motor and simulate torque converter stall and power it would be a good idea but the weed eater is a better idea I say for sure do that one after u figure out the leakage and test the transmission fluid
It could be down to the filament I used or a calibration issue, but I think further testing with this could be fun!
@@CamdenBowen yes very 😅😅😅
You are halarious, plz dont stop making videos !
Thank you! I'm actually working on my next video already!
wait putting the scale to the negatives was actually really smart I don't know if I would've thought of that.
To get my FDM project water tight I rubbed it with acetone. That worked really well.
This is super cool!
Also slick hair today o7
Ayyy thanks!
I think you should put a small bellows type expansion port on that or maybe a piston with a light spirng to keep the pressure down when the fluid heats up. It would not have to be very big. You could put a large volume like a liter of fluid in a graduated container at low temp. Then heat it to 30C and see how much volume it gains. Then you could calculate how big to make the expansion relief. Perhaps just a thin walled panel of sufficient area on the housing would flex enough to keep most of the fluid inside when it heats up.
Very cool. I might have to make one!
I will provide the files in the description!
@@CamdenBowen thank you!
Another cool video! Thanks. I wonder what would happen if you chilled the oil before use?
You could easily put some fins on the sides of the coupler as well; to serve as air cooling.
Thank you! At around 5 degrees give or take, I notice the oil gels up and becomes more of a grease until it warms up. Since its gelled up it doesn't work properly until the oil can flow. However, since the oil is more viscous when its cooler it does work with greater efficiency
something I would love to see would be a different type of dynamic torque test, how the torque delivery changes at different output speeds. it seems like it wont be that different from when its stopped because the main thing that delivers torque for your design is difference in input and output speeds but the g forces may affect its torque output in strange ways.
Now we just need a baby (Open Source) 3D Printed Dynamometer lol
Theoretically, if I knew the coefficient of friction between the arm and the shaft where the output shaft is, it may be possible to perform such a test using a method similar to brake dynamometry. But that may be for a much later date lol
@@CamdenBowen yeah, I guess the only way to measure dynamic torque would be to build a dyno. awesome video and awesome idea though, looking forward to your next video.
Your videos are always so quiet I have to crank up the volume and then when a different video comes on BOOOM!
Drop what your doing. Camden dropped a banger.
Maybe consider a tube of gasket maker to make your seal between the two halves. Works for my mower 🤷♀
Awesome follow up! I think that the horizontal arm doesn't behave like you think though. The angle between the point of contact and the center of the rotation is actually the interesting angle. You can imagine there is a straight stick between those two points. It would work exactly the same.
It is not the same tho. The normal force is perpendicular to the surface his method is ok
Realistically, when it heats up and loses torque, it's because of the design and the fluid. Modern ATF is fairly thin, and runs fairly hot, but still transfers torque well.
In terms of sealing, it needs to be painted with epoxy paint inside if you want to have any hope of it not leaking. FDM prints aren't water tight without it.
I've had a custom-made torque converter fitted to a car to improve fuel economy round town - it made a massive difference. To improve the effectiveness of the fluid coupler though you may want to consider designing angled vanes in the turbine and impeller.
How does a torque converter increase fuel economy?
@@PrimedProductions it was an automatic that already had a torque converter, but the original configuration had a non-zero stall speed. Manufacturers do this for their own reasons including smoothness at tickover, resistance to stalling when put in gear, minimising creep speed and 0-60 performance. This is at the expense of economy. I had it rebuilt with the lowest possible stall speed because I was willing to sacrifice everything else for economy. But to point out, the early Mini automatic was more economical in town driving than the manual. That's because it had a generally low-revving torquey engine and a torque converter with a low stall speed and a 4-speed automatic that would go up through the gears quickly. This means that the engine speed was nearly always low compared to the manual in town driving
You mentioned the expansion as the oil heats up, but another factor could also be the fact that the viscosity decreases as temperature goes up as well. An old mechanic trick for minor oil leaks on cars in hot climates was to just go to a slightly thicker oil, which would often reduce the seepage. I think this could also contribute to the torque falloff you saw at higher temps. I'd be interested to see what happens if you let it cool back down and then test again. That should clarify if the falloff is only related to fluid temperature, or if the small amount of fluid loss might be a contributing factor.
Incidentally you were quite right about heat being the major killer of automatic transmissions, but I think for reasons you didn't really cover. If it was just a matter of the fluid being too hot, they would work normally again once cooled. In heat related trans failures, the actual issue is that the oil gets hot enough that it actually changes chemically, vastly increasing the viscosity (essentially it "cooks" for lack of a better term), though these temps are way higher than anything you encountered, above 300F was our rule of thumb for standard ATF. The friction material in the clutch packs then wears excessively as a result of the much higher load due to the thicker fluid, and eventually wears to the point where the clutch packs no longer have sufficient friction to stay locked together (this is the cause of the slippage which is one of the early warning signs of a transmission that's on its way out). I have even seen situations on extremely old vehicles where simply changing the transmission fluid was enough to cause the transmission to fail, as the much thicker fluid was the only thing allowing the clutch packs to grip at all.
Your videos are impressively good considering your sub count
Thanks man!
Most modern automatic transmissions actually don't rely on the fluid coupling for high speed opperation, because of the inefficiency and waste heat.
Modern torque converters have, in addition to the fluid coupling, a wet clutch which engages once the converter reaches it's synchronous speed, ensuring maximum efficiency and protecting the transmission when hauling loads.
for the overloading problem you can make an armature much longer to reduce the force seen by the scale.
I tried this, what kept happening was the arm was too long and would flex enough that the torque reading was off by quite a bit
@@CamdenBowen ah, maybe cutting apiece of wood for the task then. or doubling up the number of arms or something. honestly that's a fun little engineering challenge in my eyes
The little scales are used a lot with ammo reloading
nice video!
maybe you can print future models in gray? it is kinda hard to see details when the model is all black :)
also...maybe you can use a load-cell and a speedometer with an arduino to properly plot the torque and RPM? (just a suggestion)
nice video though!
Thank you! I should really consider what filaments I buy, I usually buy what's cheapest regardless of the color. I may come back in the future with more testing to determine the torque when the output shaft is spinning rather than locked, so that may not be a bad idea!
Very interesting, especially how much the torque dropped once the oil heated up. Years ago, I tested the stall speed of a car's torque converter with hot fluid (about 180 degrees) vs cool fluid before the trans warmed up (about 90 degrees) because I was curious how the fluid's viscosity would affect the torque converter's slippage. Surprisingly, the stall speed was only about 100 RPM higher with hot fluid than cool fluid (2800 RPM vs 2700 RPM). I would have thought the torque converter would slip much more and be way less efficient when its fluid is so much thinner, but it didn't seem to matter much in my test. Perhaps the fact that a torque converter has a stator unlike your fluid coupler and the obvious difference in the fluid's viscosity stability explains the differing results.
Make an o-ring groove or a gasket or just silicone it to make a seal to prevent the leaks
You are awesome
Thank you!
Maybe comparing this to a centrifugal clutch and the clutch you made earlier would be interesting. And having a heavier scale would be better, could break the load cell as someone else said.
I think it'd be near to actually have it used in a real application like a bike or something and see how it holds up to other designs. Maybe a tension scale will work better as well
Awesome video Camden!
Do you maybe think the less torque being produced at higher temperature was maybe due to the viscosity of the fluid going down as temperature goes up?
Thank you! I noticed vegetable oil is very temperature sensitive, at around 5 degrees or so it almost turns into more of a grease but after 15 degrees it becomes a very thin fluid. Past that it gets even thinner so it's very possible that it was responsible for the low output. Actual transmission fluid is built to have a much more consistent viscosity across a much larger temperature band
I wonder if you could make a drill/impact use a torque converter to tighten/loosen screws, just a random thought. it could also help with protecting screws and threads from getting stripped/breaking
if you completely fill the oil and leave no air in there, when you heat it up, the oil will expand and as there is no air pocket to allow for expansion, it will push it self out via any way it can find, in your case, it would be the join of the outer assembly :)
It would be interesting to see how much the fluid viscosity changes during a test like this.
If you added a one way clutch and a stator you'd have a mini torque converter. What a cool project!
Thank you! I've considered building a second larger one for that purpose
Thanks for the reply. Your channel is really good!
What was the drill output?
just coat the housing on resin, if you use the stuff for boats you can seal 3d printed intake pipes and stuff like that for your car (asa)
Yessss finally
7:16 💥 mind blown all this time i didnt need a bigger scale.
if leakage remains a problem, a possible solution might be in making an inner and outer shell for each half, then gluing them together with jb weld or thin spread of silicone to create a fluid tight membrane.
great video, a fun experiment, with tons of possible uses.
10:20 well it makes sense that it seeps out since you filled it full, with the temperature increase the oil will expand and find its way out.
You measured the housing temperature which being plastic, I would assume is MUCH lower than the actual oil temperature.
Im sure that the fluid leaked out because of it expanding due to the heat, and because it was filled up to the max there was no room to expaned other than escaping. Maybe a little bit of an „air gap“ will prevent it from leaking. Just like the aio‘s pc watercooler🤔
I would have liked to see how much torque is lost from drill to the ouput shaft
Tips for prevent leaking:
1. Try painting the 3d printed parts with epoxy, to prevent/reduce leaking.
2 You can also fill the 3d printed parts packed with grinded/powder salt, and nuke the parts in the microwave fusing the plastic layers together.
LETS GOOOOOO
Dynamic torque like if the input is at 1000rpm and the output is 500 rpm lower or 200 or 1000. What is the power. Than @ 1500 rpm. Also shock it by violently stoping the output from 500 rpm.
Thos would be awesome scaled down in a small RC drift car or something.
I wonder how close the internal oil temp is to the outside shell, there might be a decent difference?
I wouldn't be surprised, the outer shell changed quickly in temperature which leaves me to believe the inner temperature must have been much greater
1:20 oh thats the same one i use to weight my trees😂
I'd print it in resin and seal the two haves with rtv gasket maker.
The part of the spheres reminds me of how an automatic variator works. Like tho ones in modern scooters. They have weighted rollers that push a pulley outwards when spinning. The pulley is flat and kinda conical in shape, when it extends for centrifugal force it forces the pulley out and the belt runs on a wider point of the conical pulley, changing the transmission gear.
...I'm not actually explaining to you and my expl sucks i know. I jus didn't remember the name of the contraption.
You mean like a CVT? I have a video where I made one and demonstrate it if that is what you mean
@@CamdenBowen yup that 😅 I was writing at 6 am. CVT, for constantly variable transmission if I am right. I was confusing with the omocinetic joint which is also CVT but for constant velocity.
I might be wrong, me nuh ingineer nor motherlanguage 😅
im wondering what would happen if you use low-viscosity grease meant for high temperatures?
Plastic is also a lot less thermally conductive and has a lot less thermal mass than steel or aluminium so the oil inside was probably a lot hotter. I wonder how easy it would be to cast the parts?
Probably not too hard, the challenge more lies in achieving proper tolerances and making sure everything is perfectly balanced
Oil expands when heated. Not a lot but it does expand. If you fill the chamber completely and seal it shut.... leakage
To account for this I had filled it about 3/4 of the way, when it's overfilled the fluid can no longer circulate properly either
Torque converters in car transmissions are actively oiled through a pump, right? Depending on the flow rate in and the drain orifice sizes would determine how much oil is in the converter under normal operation. Any idea what that is and how the air to oil ratio affects the performance?
Less gooo
I can understand grams fully well, but I'd appreciate if you would have a caption to translate temp from Celsius to Fahrenheit for Americans such as myself. I understand I could look it up and calculate the values myself, but doing that sort it takes me out of it when I'm trying to enjoy some fun informative content. Those are just my two cents though
I think your horizontal arm does not what you want it to do. The connector between the horizontal part of the arm and the vertical part would have to be a bearing/revolut joint. In your setup the vertical part of the arm puts a momentum onto the horizontal part of the arm and thus increases the torque. Instead of adding a joint, you could also just use math to get the true torque. Like what you showed at 5:24. Just add a sin() or cos().
Cheers :)
Thank you! while it may be the case, to determine the force using trigonometry would require precise measurement of the angle between the plate and the arm, meanwhile my apparatus provides a more accurate answer without the need for trigonometry
@@CamdenBowen I'm fairly certain you are getting a wrong reading right now which is off by a factor of cos²(). As long as your vertical beam is fairly short, the angle is small and therefore your results are not that far off. But imagine if you had a long vertical beam and a long horizontal beam. Also you can get the angle by arctan() or you could just angle the scale so that the scale plane goes through the rotation axis.
@@CamdenBowen Or think about it like this: At 5:26 the scale experiences the same force when the arm is horizontal and when it is not horizontal.
@@CamdenBowenmax is right. Your system is no different from a straight beam that stretches between the output shaft and the contact point on the scale.
That scale trick sounds weird to me. Usually the limit is set there becouse the sensor is overwelmed and probably becomes very innacurate or it just might break, so the pressure plate probably is designed to physically bottom out when it reaches that kind of weight. Unless its limit is actually 1 kg... for this specific case
Yea in retrospect it isn't very smart lol, but it offers a slightly more accurate result than it did maxing out at 500
@@CamdenBowen Im just surprised that that actually increased the limit how much weight it could handle
@@CamdenBowen sorry but its not really accurate if you can't be sure of its readings being accurate, when you push the sensor out of its range set range it might act different as when its in spec.
Get a thicker fluid, shock oil from RC cars has a range of thicknesses. They're silicone based and you can get it so thick it's almost wax in nature (too thick for this imo) but vegetable oil is way too thin so you're not going to get as much torque transfer as you could get with a thicker fluid.
Cool beans.....
Making the arm horizontal isn't doing what you think it is. the force at the tip is still rotating around the axis of the fluid coupling, regardless of whether the arm is a straight line to the balance or an L shape or any other shape. It would be better to have the point of rotation level with the top of the scale
What's the torque of the drill? Hence efficiency.
OMG I have the exact same steel balls! Are yours magnetic too?
No, they are just .50 caliber steel balls. I initially bought them to fire out of slingshots
if your balls are magnetic, you should probably see a doctor.
Hype is real guys
Increase in temperature = reduction in viscosity = lower shwar force = lower torque transfer
It’s leaking oat from the oatside of the hoesing
Could you do an efficiency test. Also, can you add imperial units.
The closest thing I had to an efficiency test was comparing how the torque transfer changed as the temperature increase, its difficult to performed a efficiency test with the equipment I have. If in the future I do mate it with a weed-eater motor I may then be able to determine its efficiency
No imperial units please.. Metric makes more sense.
@@Matthews_MediaEuropean spotted 🚨 🚨 🚨 wtf is a kilometer🦅 🦅 🦅
@@blingblingdog6958 Actually South African.. and the whole world except for the US uses metric so...
3:38 if anyone wants to read the comment and see him stroke his luscious hair.
I'm still trying to get past printing the owl my printer's sd card came with. Can't get files to it or use it 🤷
I usually print via USB cable instead of an SD card
i can only imagine the "people also bought" section for that pocket scale. its actually kind of illegal to own that scale in some cities too! where i live there isn't an explicit law prohibiting owning one, but there is a ton of case law where people have been tried and convicted of intent to distribute narcotics using ONLY the pocket scale as evidence! if you own both the scale AND literally any kind of ziplock bag, you are hosed. if you own little parts bags, you will do serious federal time. its pretty messed up, but that's how it goes here
Should plane the surfaces flat and than use some silicone gasket maker. It might help and is almost like resurfacing an engine for a new head gasket
would be cool to coneckt it to as you sead a weed eater enigne probly will need to beath it up a fare bit and make it bigger you could also coneckt it to your gearbox and make a gokart. if you neeed or want more torque from it you could put ep90 in it(ep90 is a heavy oil for axles realy thick) or even make a clutch that coneckts the output with the input to lock the sides together ised for when a vhecle is moving it will lock it together makes it more efishant will need to relece the clutch to change gear thow. good luck with my spelling
I'd probably need to make a larger one for a weed eater, the channels are probably too small to effectively transfer that much torque. Something heavy like axel fluid or just transmission fluid may defiantly help under heavier loads, but if it is too heavy then the fluid will not vortex very well and it may cause increased slippage
Is there a way to effectively alter the stall speed of this
Blade pitch angle mainly, torque converters can have different pitch angles on the stator that affect the stall speed
@CamdenBowen So if I pitched them in the direction of flow it would in theory lock up sooner. I've got this fun idea to essentially 3d print an rc pull truck and over engineer everything
not knowing how much time you spent with the previous tests it seems it might have been leaking and you didnt notice at the time and the stain spread looks larger than the volume leaked because wicking spreads it out over a large area
The fluid does not leak out when it is cold, I should have mentioned in between shots once it cooled down it was clean. Once it warmed up enough however it was able to seep past small cracks and out
@@CamdenBowen thats pretty much what i was expecting, hot oil is considerably thinner than room temp. im surprised to know the seals on the shafts held up well, thats where i expected the leaks to originate. what material did you use for them?
You need a stator !!!!
Given the second pun about the scale I had to tell you that yes basically that's what a scale for apart of weighting stuff is to dont' waste too much of the stuff and in the end dont lose money. Pocket scales are meant for gold bugs or micro electricians or people which uses small stuff, or does experiments like you.
I have one for proportioning epoxy resins with hardener, and the tooling gel expecially is always in small batches less than 25g mixed with 8% hardener. The correct proportion does not define the hardening time like in polyester resin for fiberglass but influences the properties of the hardened material.
I think drug pushers that use it to carry it around are dumb, since it's an immediate proof of the dealing intentions. Wether for Pablo Escobar as you said, it might be a bit out of sc-🤔
Even actual tyranny fluid heats up and expands. Thats why you have a hot and cold measurement on your cars dip stick. Point is heating up expands the fluid and you have an air tight housing. So it’s pushing fluid out. Easy said than done, But needs a vent.
increase the blade count... compare several.
only fill to 1/3rd.
500g torque.. not great, not terrible.
(get the reference?)
negative 360 minus 300 hurts my sensibilities. i would have loved to see 300 minus negative 360. i know its the exact same thing or at least the absolute value is, but subtracting the larger number just feels icky :/
I got lazy and figured people would get what I was putting down
@@CamdenBowen yeah i get it, just couldnt let you get away with it without razzing you a lil :p awesome video anyway, keep em coming!
Pablo Escobar was probably in the truck weigh-station scale range, not the pocket scale range!
Good point!
Make a 3D printed rotary engine
Try making a paper engine!
Lots of fun, but hard to make
Not a bad idea, I think it could be fun!
Was waiting for the drug joke about the scale.. One day kids won't even know who pablo is xD
Lol make a DIY load cell
Now do it again with ATF :)
Awesome project, and thanks for sharing. Do you know the torque output of the drill at its various speeds? Would be interesting to compare that against what came out of the coupler and how transmission fluid changes it.
Looks like this thing is acting more like a viscous coupling
I don't think that's what dynamic torque means
Warning: Do not play a drinking game with "actually" ;)