Difference Between Basic, Hydrostatic and Hydrodynamic Bearings

Fluid bearing - Wikipedia, the free encyclopedia

GA

I don't understand why the OP (and others) ignored to read this link? This is all he needed for an answer.

Thanks for the clarifications. I am attaching the bearing tree family. Please amend where you think I have made a blunder thanks.

Are "stuffing boxes" considered to be "slide bearings"?

Water lubricated bearings.

There is also mag-lev, electrodynamic, permanent magnet bearings, discussed in this wikipedia article....

active and static magnetic bearings

Personally I have always liked wooden bearings. Very useful in food preparation applications, and extensively used here in MY shop. I use red oak, and drill oil risers. They last longer than many other bearings. The pores in the wood contain the added oil, and if the bearing starts to heat up, the oil seeks out the hot spot, preventing wear.

And there was one that used cylinders caged with a serpentine spring steel tape trapped between two completely static races. I thought THAT was really cool, but don't know the name of it. Maybe somebody can help me out here. It would make an awesome linear slide bearing. The load was carried on the cylinders which projected out the sides, the races just stayed static. (a memory of a magazine article dredged up from around twenty years ago.)

I like babbit. Easy to fix. Just support the shaft, and torch the assembly, and presto! New bearing! You often don't even need to take the assembly apart. I have a power hammer that uses those. The shock breaks all bearings except for babbit, but I have to retorch the bearings about once every six months.

Magnetic are great, York and Turbocor have perfected those.

But good old wood, saved me on a Thanks Giving day years ago. The standard Ball failed, drilled a 7/8 inch hole in a pine 2x4, lubed the heck out of it then pounded it on a 1" shaft and got the exhaust fan back running at Petes Cafe. Went home and enjoyed a nice turkey day. It was over a week later the OEM beargin arrived, went to change it the wood bearing was looking great still.

In the right branch: why axial ball? Should read rolling element bearing.

Then next with any shape of rolling element is ok.

Typical load is most often radial plus axial, think about a grinding or boring spindle.

RHABE

Rolling _ antifriction _ Ball Roller

Ball_ load-axial _radial_ axial + radial _ 4 points contact (it takes force loads AND moments!)

Roller cylinders _ needles = loads :radial_ axial (the needle is a slim cylinder !)

Roller tapered _ conical = loads :radial + axial

Rollers barrels_ self adjusting (angular) radial_ axial heavy radial + limited axial loads.

Combined needle + ball for important radial and limited axial loads.

I would revise the rolling side which is less complete and less structured than the sliding side.

The best you take a catalog from SKF/FAG /Timken or any other big manufacturer and have a look at the program and make the tree accordingly.

In the sliding bearing zone attention a journal bearing can be hydrodynamic and grooves destroy its carrying capacity! It is a VERY complex domain of the technique and many make errors in the design and choice of the bearing type they want to use in an application. Even the bearing salesmen are many times on the wrong side (at least I had some recommendations which were totally not acceptable, if I would have followed the suggestions the project failure would have been SURE!).

Wow! Very unusual terminology, logic, parallelism, etc.

Perhaps seeing and touching some bearings would help. Maybe looking through bearing catalogs would help. Or give a bearing vendor a call and ask for a tapered axial ball bearing, or a cylindrical axial ball bearing.

1. If you looked at a needle bearing, you could not imagine calling it a ball bearing. It is a specialized roller bearing, with very thin rollers.

2. The two basic types of rolling element bearing are "ball" and "roller".

3. Axial ball bearing is a type of ball bearing, not the other way around. If you specify axial ball bearing as a subclass of ball bearing, then you should specify radial as a subclass. If you specify those, then you should also specify angular contact, (which can accept more thrust (axial) load than a standard radial bearing), and ball thrust bearings (which accept only axial load).

4. Tapered and cylindrical are two common versions of roller bearings. Spherical roller bearings are a third type. A fourth type is a roller thrust bearing, which can have short needles or tapered rollers, or even barrel-shaped rollers and spherical races.

5. If you specify "advantages over other types of bearing" you should do so for each type. You might also specify disadvantages, such as the need for an oil pump for hydrostatic bearings.

6. Pressure bearing is rarely use terminology, because is it ambiguous -- all bearings deal with pressures of various sorts. Sometimes the term is an incorrect translation of "thrust bearing". Perhaps you got the term from this article, which is also incorrect in dividing rolling element bearings into axial ball vs roller.

7. The path from hydrostatic or hydrodynamic to thrust and then back to hydrostatic again, seems confusing. You seem to be saying that a hydrostatic thrust bearing has advantages over other types. (Other types of thrust bearings... or other types of bearing in general?) The most common hydrostatic bearings are the journal bearings in most engines. They are not thrust bearings, but share the advantages of any hydrostatic bearing.

8. The four advantages you give for hydrostatic thrust bearings are arguable. In practice,the ball bearings commonly used in electric motors are very low friction, and highly reliable (and do not have a need for pressurized lubrication).

9. There are plain bearings that are neither hydrodynamic nor hydrostatic (in the normal use of these terms as applied to bearings). Teflon (and graphite, etc) bearings don't fit well nor do sintered bronze bearings.

So what is more appropriate terminology / logic for this?

My understanding is that there are two types of bearing - rolling contact (anti-friction) and sliding contact (plain).

Within plain bearings, there are two types - hydrostatic and hydrodynamic.

Both of these types can be either journal, thrust, or linear.

Is this correct? If so, where do air bearings (aerodynamic, aerostatic) fit? Are there other types of plain bearings other than hydrostatic and hydrodynamic?

Where do spherical plain bearings fit?

No vendor catalogues actually lay any off this out in a sensible or logical fashion.

Thanks