Steel on Steel Plain Balances
DescriptionA plain bearings, or more simply slip bearing and smooth-flip bearing, is essentially the easiest form of bearing, consisting of just a single bearing surface and no rotating parts. As such, the journal moves over the bearing surface without any rolling elements. The simplest example of such a plain bearing is a roller shaft rotating in an open hole. The bearing surfaces are machined smooth so that they are complementary to each other.
This feature makes them very useful, because the inner and outer rings have equal contact pressure across their whole surface area. Also, they have nearly zero slippage. And if there is any slippage, it's usually very minimal. If one side of the ring wears out or gets damaged, the other side will take over, hence the term "self-cleaning." Generally speaking, these kinds of bearings are used on inner ring sets, inner rollers, spindle sets, and on some precision bearings.
Another feature of this kind of bearing is that the inner and outer rings can be made from different kinds of alloy. For instance, they can be made from a high-carbon steel, high-carbon soft steel, or a low-carbon steel with an overlay of low-density carbon. Usually, the alloy selected is chosen based on cost. However, most suppliers of these kinds of bearings indicate that they come in a variety of standard alloys.
On another note, this kind of bearing has its own unique set of advantages. It is capable of retaining both its inner and outer rings in place even upon a load change. Moreover, these kinds of bearings have a nearly limitless number of load ranges, including both axial and radial thrust, a factor that most other bearing designs do not offer. Lastly, a typical spherical plain roller bearing offers good wear resistance even under high heat loads.
Steel-on-steel plain rolling balls bearings (often called "PTFE") are different from most of the other bearing types. They can be characterized by their higher density and by their higher tensile strength. Moreover, these bearings are not only highly cost effective, but they also offer a very robust mechanism and a good measure of dimensional stability. In fact, such bearings have been found to be quite useful for a variety of applications, including rocket nose cones, aircraft wheel bearings, and precision-shaped shaft seals.
Steel-on-steel plain rolling balls bearings are usually manufactured using high-quality steel alloy. However, since these are heavier than plain bearings, many suppliers of these kinds of bearings have developed the technology to produce them using polymer vanadium or PTFE plastic. These polymers offer good thermal conductivity and excellent lubricity, while sacrificing some of the hardness of the steel that is inside the polymer.