Skip to main content
36 votes
Accepted

How do ball bearings not crack from a load concentrated on an infinitesimally small point?

Nothing is rigid, the raceways and the ball in a ball-bearing are no exception. The contact area deflects and accommodates the ball in a small contact surface, not a point. Also, the balls take the ...
kamran's user avatar
  • 22.4k
17 votes

How do ball bearings not crack from a load concentrated on an infinitesimally small point?

TL;DR: ball bearings deform due to Hertzian pressure and therefore distribute the load However, the reason balls (rolling elements) don't easily crack is the ductility of the material (and to some ...
NMech's user avatar
  • 24.4k
16 votes
Accepted

Is there such a thing as a sand-proof bearing?

A bearing with contact seals is reasonably robust against airborne dust. It is a rubber seal that contacts both the inner and outer ring, leaving no gap. Such bearings do not rotate as readily as ...
jpa's user avatar
  • 1,943
10 votes
Accepted

What are 1 ball and 2 ball bearings?

A "1 ball bearing" does not mean the bearing has 1 ball. Or 2... It means that the motor / fan has been designed with one ball bearing assembly - which may contain 6, 8, 10 or 12 balls ...
Solar Mike's user avatar
  • 15.8k
9 votes

Is there such a thing as a sand-proof bearing?

Since it's low speed you could just use bushings. Unlike ball bearings with open cavities inside for sand to get into, there shouldn't be any real open spaces for large grains of sand to get into if ...
DKNguyen's user avatar
  • 5,621
8 votes

Is there such a thing as a sand-proof bearing?

With high enough mechanical advantage (presumably you're gearing wind power or a large motor down heavily to make 1RPM), it's unlikely the bearings would fail you within a week even if scraping away ...
ti7's user avatar
  • 181
7 votes

Jet Boat Engine Part Identification

It is a high pressure seal and bearing unit. The metal assembly to the right with the yellow parts is the drive coupling. After Sam’s comment and looking at that part again, there are 3 distinct ...
Solar Mike's user avatar
  • 15.8k
6 votes
Accepted

Refute my assumption: Bearings Don't Improve Efficiency

Your initial assumption is a bit flawed. You can not just draw the conclusion that all friction is the same. It is like saying all birds i know of can fly thus all birds can fly. Which is obviously ...
joojaa's user avatar
  • 3,577
6 votes
Accepted

How/why lubricating a rolling bearing would make them spin less time (dissipate energy faster)?

The lubricant you put into the spinner bearings has both viscosity and surface tension, and it coats the rotating parts inside the bearing. Therefore, as the spinner bearing revolves, it churns the ...
niels nielsen's user avatar
6 votes

Off-centre actuation

Your mechanism is going to lock up like the old car jacks immediately, due to differential raising of the platform. I am sorry but it looks like a textbook example of what not to do. in most real-life ...
kamran's user avatar
  • 22.4k
6 votes
Accepted

Off-centre actuation

Does anyone know if this would be a good idea? The proposed design has poor rigidity towards torsional loads. It doesn't matter whether the actuator is off-center or if the load is off-center: if ...
jpa's user avatar
  • 1,943
5 votes

What is the exact concept of bearings?

If that is true, then would not be better off just to remove the whole setup and have the axis of rotation free from bearings ... Ball bearings change a system from sliding friction (as in a journal ...
Transistor's user avatar
  • 10.8k
5 votes
Accepted

Wire bearings on actuators on military ships

These are called “wire rope dampers” or “wire rope isolaters”, and their purpose is to increase the time over which recoil energy is transferred into the mounting, thus reducing the peak force.
Jonathan R Swift's user avatar
5 votes
Accepted

How this adapter inside the bearing is called? How to find/make a replacement?

Regarding the name, I don't think that there is an official technical name, but then again I'm not a native speaker (nor can I speculate on the function of this shaft which in some cases might lend it ...
NMech's user avatar
  • 24.4k
4 votes

What type of bearing could be used to keep a utensil level while being moved from plate to mouth?

One difficulty here is that the masses involved are quite small so you need a very low friction bearing. Many industrial bearings are designed for high loads and speeds with quite close tolerances so ...
Chris Johns's user avatar
  • 15.2k
4 votes

What does 1 x rpm or 2 x rpm or 3 x rpm in vibration analysis mean?

RPM = revolutions per minute. In the context of vibration monitoring, 1 x rpm means a vibration frequency that is the same as the rotation speed (one vibration oscillation per revolution of the ...
alephzero's user avatar
  • 12.5k
4 votes
Accepted

Is there a reason for the bearing to be held in place by this flimsy star chamber rather than a solid seating?

Those thin flaps allow the bronze bearing inside to tilt about slightly and thereby come into alignment with the axis of the fan shaft, thereby minimizing noise and friction. If the bearing as a whole ...
niels nielsen's user avatar
4 votes

How do ball bearings not crack from a load concentrated on an infinitesimally small point?

Bearings of different designs have point contact or line contact. The roller bearings have a curve line of contact - only have to take one apart to see the wear path on the inner and outer race. As ...
Solar Mike's user avatar
  • 15.8k
4 votes

How do ball bearings not crack from a load concentrated on an infinitesimally small point?

They are very strong, and it is not quite a point as there is some elastic strain. Rolling element bearings are nominally HRC 62, roughly 300,000 psi yield. And have residual compressive stress at the ...
blacksmith37's user avatar
  • 6,134
4 votes
Accepted

Why does the taper on tapered-roller bearings help support axial loads?

My understanding is that by tapered roller bearing you mean something like: Figure: (source:Wikipedia) Obviously the axial load is also converted into axial and radial load depending on the cone ...
NMech's user avatar
  • 24.4k
4 votes

Is there such a thing as a sand-proof bearing?

Protect all the bearings. Boots as used on cv joints will protect bearings. But there are boots designed to mount on various surfaces. Bearings that are not protected will suffer an increased rate of ...
Solar Mike's user avatar
  • 15.8k
3 votes
Accepted

How does the SRI "Abacus" rotary transmission work?

It's just a fancy rolling cycloidal drive (not that that being simple makes it any less cool). It really bothers me that all the available articles only compare it to harmonic drives when it only ...
Auptimist's user avatar
3 votes

What makes crosshead bearings hard to lubricate?

The crosshead bearing slides within a track and connects to the conrod and then to the crankshaft. In a vertically oriented engine the pressure on the bearing is always downwards, resulting in a ...
Donald Gibson's user avatar
3 votes

What does it mean that a ball bearing can handle thrust load but a roller bearing can't?

if you look at a ball bearing in cross-section, you will see that the balls are assembled into the two races in such a way that the races have side walls against which the balls can press as they roll....
niels nielsen's user avatar
3 votes
Accepted

What is this kind of bearing called

I think it is similar to what it is called by MIT Fundamentals: Flexural Rolling Bearing or Rolling Contact Flexure in section 10.14. As is often the case, a hybrid system can combine the best of ...
Gorkem's user avatar
  • 146
3 votes
Accepted

What is the typical rpm variance-tolerance of a roller bearing?

The maximum speed for a bearing recommended by the manufacturer can be due to one of two limiting factors, Thermal, or Mechanical. The thermal speed rating (often called "reference speed") is ...
Jonathan R Swift's user avatar
3 votes

Refute my assumption: Bearings Don't Improve Efficiency

Bearing have rolling elements specifically designed to insulate the two moving surfaces from coming into contact with each other and let the move freely (almost). There are many types of bearings, ...
kamran's user avatar
  • 22.4k
3 votes
Accepted

How to make a choice between rolling element bearing and journal (plain) bearing?

rolling element bearings produce less friction, last longer, can position a rotating shaft with greater accuracy, and do not require pressurized lubrication in order to carry large loads. sliding ...
niels nielsen's user avatar
3 votes
Accepted

How does the Nest Learning Thermostat bezel rotate without bearings?

Just prior to this point in the video you can see that the display has been inserted from the front and this portion will be added from the back and screwed in. All that is required is to ensure that ...
Transistor's user avatar
  • 10.8k
3 votes

Conventions regarding sliding and press-fit tolerances for shafts and bearings

Shafts and bearings usually use interference or transition fits - they shouldn't slide and for installation you should use force - some kind of press or clamping tool would be best, eventually if such ...
elementiro's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible