The foundations of the three lubrication types: boundary | mixed | hydrodynamic
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- Опубликовано: 27 авг 2024
- I've talked about this specific curve a number of times in these videos. It's called the Streck Curve, and it really tells you a lot about what you need to know about lubrication. For example, there are three different types of lubrication, boundary mixed and hydrodynamic lubrication. We've broken those down separately in other videos. But how exactly do we get to this chart? Let's build it up piece by piece from some building blocks that we have from high school physics.
lubrication.ex...
I collect waste motor oil if I run the oil through a mini Refinery around 700°. The vapor is caught in a heat exchanger condensed down into a liquid I get a 5 gallon bucket and an hour or two I get bucket after bucket I can get multiple buckets per day six or seven buckets the oil that I get sits for about a month after that then I treat the oil I mix it with Ethel oxide then the oil sits for about a week or two all the t a r s polymers and odors are stripped from the oil and end up at the bottom of a container the oil becomes clear and orange after this it is mixed with water about a week later all the water settles out of the oil and you end up with a transparent bright orange oil in the diesel Spectrum it runs an engine perfectly with tons of power this liquid only cost maybe 10 cent per gallon I've been doing this for almost 10 years
What equipment do you use to heat and fractionate the old oil?
Wow I finally understand this concept, thank you so much.
Great!
Very insightful… Thanks a million Prof. Rafe
Thanks Alex!
Excellent presentation!
Thank you kindly!
Hello! Just discovered your channel and I really like it! Lubrication is a crazy complex topic and I am happy I found this resource to understand it better, thank you! I own a vintage motorcycle and the lubrication sistem in it has one type of oil for the gearbox, engine and the (wet) clutch too, poor oil has to do a lot.. and the fact that the oil changed and evolved a lot since the motorcycle was produced makes me a little worried. I am curious about the special oils used in bikes since they have multiple roles.. I guess that is one of the reasons they have to be changed very often compared to cars.
tks so much!!!
You're welcome!
So on something like a telescoping tripod joint, you would be mostly operating in a boundary/mixed boundary condition? What would be the appropriate grease? An NLGI #1 EP might be too thin to prevent the outer race of the roller bearings from pitting the CV cup under heavy load, but a NGLI #2 might be too thick to adequately lubricate the needle bearings in the inner race. Is there such a thing as a NLGI #1.5 that could give adequate lubrication to the CV cup and the needle bearings?
So grease and rolling element bearings are a whole extra kettle of fish and the NGLI grease consistency is not a critical value for rolling elements, it is mainly a matter of temperature range and even that depends of the general formula. (Also the NLGI grades are not units of measure, each grade had a wide qualifying range.)
slow short movements are almost always in the boundary lubrication zone The boundary zone is what additives like graphite and moly or sulfur and phosphate chemistries are used to protect against; which to use depends on the specific conditions and msterials involved. anticorrsion beyond the simple protection of oil is provided by additives that lightly bond to the metal so no other molecules can touch it.
The speed is linear speed, so a small diameter bearing race at high rpm or a large diameter bearing race at low rpm can develop the same hydro-dynamic pressure.(commonly the average of inner and outer race diameter is used)
The NLGI numbers are mostly due to the amount and type of thickener, and the thickener determines properties like high temperature drop point, release of base oil, water resistance, and some more subtle properties. For rolling element bearings it is the viscosity of the base oil that matters most, the grease mainly acts as a researve like an oil soaked sponge (And a sealant to keep out dirt) and with the correct amount of grease the bulk of grease is pushed aside forming a channel for the rollers that only contains a thin film of oil. #1 will release more oil at low temperature than #2. At extreme speeds acceleration forces may require a stiffer grease to avoid being flung out our drowning the rollers.
The opposing forces are load per unit of bearing area and fluid pressure, in rolling elements the fluid pressure comes from a combined effect of linear speed and kinematic viscosity of the fluid. A light load will require less hydrodynamic pressure.
You can get NLGI #2 made with light iso30 or iso1000 as a base oil and everything inbetween.
Too thin and it has poor protection in running condition, too viscous for the load combined with rapid startup and you can get skidding. Often some light static preload is used to prevent skidding. To viscous in running condition just wastes power.
@@mytech6779 Doesn't really answer my question regarding telescoping tripod joints with needle roller bearings, inside an axle cup.
The outer race is hardened steel and the factory grease is a polyurea NLGI #1. The roller bearings tend to cause pitting on the surface of the cup under sustained heavy loads, and I along with others believe the issue is caused by the lack of viscosity or EP additives. An NLGI #2 grease has been shown to produce less wear on the CV cup. On the other hand, by using a thicker grease one risks starving the needle bearings in the rollers. However the rollers only move ~10mm.
In this specific application, is there a way to give adequate protection to the metal surface in the cup and ensure the needle bearings aren't starved of grease? Or will this be a compromise regardless of the grease used?
@@rolandotillit2867 The answer is in my first post. only moving 10mm it will always be in boundary condition and you definately need the right sort of ep addiitives, maybe a slightly tackified formula. Contact a lubricant dealer, they have whole books of info on which products for which uses.
Again NLGI is not viscosity, it is "texture".
Polyurea is generally a high performance thickener but I usually see it in high speed parts.
@@rolandotillit2867 And yes in short, some situations can never achieve great lubrication and the parts will either need to be under loaded or considered semi-consumable wear parts.
How can i get membership of this channel ??
There should be a "join" button next to the subscribe button. I think it's only available on certain devices, but should definitely be available on desktop. If that doesn't work, it could be that RUclips memberships aren't available in your region yet. If you're looking to access the member videos, I also post the same videos to my website. lubrication.expert. If you sign up to LX Pro you'll have access to everything!
Kind of Mckees Investigation curve
Nice video sir..I have questions sir..can I write mla 1 online exam without a training certificate?
As I recently found out - no. You actually need to upload a verified certificate before you can take the exam.
@@LubricationExplained Sir are you taking any traning course ??or where can i go for traning??
Keep going man, this shit is cool!