FACTOID # 13: New York has America's lowest percentage of residents who are veterans.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Ball bearing
Working principle for a ball bearing.
A 4 point angular contact ball bearing
A 4 point angular contact ball bearing

A ball bearing is a common type of rolling-element bearing, a kind of bearing. Image File history File links BallBearing. ... Image File history File links BallBearing. ... Image File history File links Download high-resolution version (2260x1820, 955 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Rolling-element bearing ... Image File history File links Download high-resolution version (2260x1820, 955 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Rolling-element bearing ... Four-point-contact radial bearings A rolling-element bearing is a bearing which carries a load by placing round elements between the two pieces. ... A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. ...


The term ball bearing to mechanical engineers usually means a bearing assembly which uses spherical bearing balls as the rolling elements. To laypeople the term often means an individual ball for a bearing assembly. The remainder of this entry uses the term ball for the individual component and "ball bearing" or just "bearing" for the assembly. For other uses, see Ball (disambiguation). ...


Ball bearings typically support both axial and radial loads and can tolerate some misalignment of the inner and outer races. Also, balls are relatively easy to make cheaply compared to other kinds of rolling elements. Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area that spherical shapes provide. Axial has different meanings: In geometry it means: along the same line as an axis (coaxial) or centerline: parallel (geometry), contrary to radial or perpendicular In anatomy it relates to an anatomical direction of animals and humans. ... Look up radial in Wiktionary, the free dictionary. ...


Although Leonardo da Vinci has been credited with the discovery of the principle behind the mechanics of ball bearings the first patent was taken out by Philip Vaughn, a Welsh carriage-maker, in 1791, and ball bearings were found on the Roman Nemi ships constructed in about 40 A.D.. The hull of one of the two ships recovered from Lake Nemi. ...

Contents

Common designs

There are several common designs of ball bearings, each offering various tradeoffs.


Radial

A radial ball bearing uses axially symmetric inner and outer races that are shaped so a radial load passes radially through the bearing. Most radial designs also support modest axial loads; however, large axial loading tends to separate the bearings.


Angular contact

An angular contact ball bearing uses axially asymmetric races. An angular load passes in a straight line through the bearing, whereas a radial load takes an oblique path that tends to separate the races axially. So the angle of contact on the inner race is the same as that on the outer race. Angular contact bearings allow 'combined loads' (loading in both the radial and axial directions) and the contact angle of the bearing should be matched to the relative proportions of each. The larger the contact angle (typically in the range 10 to 45 degrees), the higher the axial load supported, but the lower the radial load. In high speed applications, such as turbines, jet engines, dentistry equipment, the centrifugal forces generated by the balls will change the contact angle at the inner and outer race. Ceramics such as silicon nitride are now regularly used in such applications due to its low density (40% of steel - and so significantly reduced centrifugal force), its ability to function in high temperature environments, and the fact that it tends to wear in a similar way to bearing steel (rather than cracking or shattering like glass or porcelain). Axial has different meanings: In geometry it means: along the same line as an axis (coaxial) or centerline: parallel (geometry), contrary to radial or perpendicular In anatomy it relates to an anatomical direction of animals and humans. ... Symmetry is a characteristic of geometrical shapes, equations and other objects; we say that such an object is symmetric with respect to a given operation if this operation, when applied to the object, does not appear to change it. ... Silicon nitride (Si3N4) is hard, solid substance, that can be obtained by direct reaction between silicon and nitrogen in high temperatures. ...


Most bicycles use angular-contact bearings in the headsets because the forces on these bearings are in both the radial and axial direction. The angular-contact bearing is able to withstand such a combined load, as well as small misalignments which often occurs, due to the flexibility of the front fork.


Axial

An axial ball bearing uses side-by-side races. An axial load is transmitted directly through the bearing, while a radial load is poorly-supported, tends to separate the races, and anything other than a small radial load is likely to damage the bearing.


Deep-groove

A deep-groove radial bearing is one in which the race dimensions are close to the dimensions of the balls that run in it. Deep-groove bearings have higher load ratings for their size than shallow-groove , but are also less tolerant of misalignment of the inner and outer races. A misaligned shallow-groove bearing may support a larger load than a similar deep-groove bearing with similar misalignment.


Construction types

Conrad

A Conrad bearing is assembled by placing the inner and outer races radially offset, so the races touch at one point and have a large gap on the radially opposite side. The bearing is then filled by placing balls in to the large gap, then distributing them around the bearing assembly. The act of distributing the balls causes the inner and outer races to become concentric. If the balls were left free, the balls could resume their offset locations and the bearing could disassemble itself. Thus, a cage is inserted to hold the balls in their distributed positions. The cage supports no bearing load; it serves to keep the balls located. Conrad bearings have the advantage that they take both radial and axial loads, but the disadvantage they cannot be filled to a full complement and thus have reduced load-carrying capacity compared to a full-complement bearing. The Conrad bearing is named for its inventor, Robert Conrad, who got British patent 12,206 in 1903 and U.S. patent 822,723 in 1906. Probably the most familiar industrial ball bearing is the deep-groove Conrad style. Look up cage in Wiktionary, the free dictionary. ... For other uses, see Patent (disambiguation). ...


Slot-fill

A slot-fill radial bearing is one in which the inner and outer races are notched so that when they are aligned, balls can be slipped in the slot in order to fill the bearing. A slot-fill bearing has the advantage that the entire groove is filled with balls, called a full complement. A slot-fill bearing has the disadvantages that it handles axial loads poorly, and the notches weaken the races. Note that an angular contact bearing can be disassembled axially and so can easily be filled with a full complement.


Split-race

The outer race may be split axially or radially, or a hole drilled in it for filling. These approaches allow a full complement to be used, but also limit the orientation of loads or the amount of misalignment the bearing can tolerate. Thus, these designs find much less use.


Single-row versus double-row

Most ball bearings are single-row designs. Some double-row designs are available but they need better alignment than single-row bearings.


Caged

Caged bearings typically have fewer balls than a full complement, and thus have reduced load capacity. However, cages keep balls from scuffing directly against each other and so can reduce the drag of a loaded bearing. Caged roller bearings were invented by John Harrison in the mid 1700s as part of his work on chronographs.[1] John Harrison John Harrison (March 24, 1693–March 24, 1776) was an English clockmaker, who designed and built the worlds first successful chronometer (maritime clock), one whose accuracy was great enough to allow the determination of longitude over long distances. ...


Ceramic hybrid ball bearings using ceramic balls

Ceramic bearing balls weigh up to 40% less than steel bearing balls, depending on size. This reduces centrifugal loading and skidding, so hybrid ceramic bearings can operate 20% to 40% faster than conventional bearings. This means that the outer race groove exerts less force inward against the ball as the bearing spins. This reduction in force reduces the friction and rolling resistance. The lighter ball allows the bearing to spin faster, and uses less energy to maintain its speed.


Ceramic hybrid ball bearings use these ceramic balls in place of steel balls. They are constructed with steel inner and outer rings, but ceramic balls; hence the hybrid designation.


Trivia

  • Hard drive bearings used to be highly spherical, and were said to be the best spherical manufactured shapes, but this is no longer true, and more and more are being replaced with fluid bearings.
  • The modern ball bearing, where the balls are kept from touching one another by means of a "cage," was invented by Leonardo Da Vinci. See Bearing (mechanical).
  • German ball bearing factories were often a target of allied aerial bombings during World War II; such was the importance of the ball bearing to the German war industry.[2]
  • See Bearing (mechanical) for more information on the history and development of ball bearings by such notable figures in technological history as Friedrich Fischer.

Typical hard drives of the mid-1990s. ... Fluid bearings are bearings which solely support the bearings loads on a thin layer of liquid or gas. ... “Da Vinci” redirects here. ... A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. ... Strategic bombing during World War II was greater in scale than any wartime attack the world had previously witnessed. ... A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. ... Friedrich Fisher is considered the father of the modern ball bearing, having invented the process for milling standard bearings in 1883. ...

See also

Photo showing two ball screws. ... A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. ... A linear bearing or a slide is a bearing designed to provide free motion in one dimension. ... Four-point-contact radial bearings A rolling-element bearing is a bearing which carries a load by placing round elements between the two pieces. ... The Brinell scale characterises the indentation hardness of materials through the scale of penetration of an indenter, loaded on a material test-piece. ... SKF, Svenska Kullagerfabriken AB, later AB SKF, is a Swedish bearing company founded in 1907, supplying bearings, seals, lubrication and lubrication systems, maintenance products, mechatronics products, power transmission products, customer solutions and related services globally. ... Wingquist, Sven (1876-1953), industrialist, inventor, Sweden. ... // The Schaeffler Group is a leading manufacturer of rolling bearings and linear products with plants, engineering offices and sales companies around the world. ... A thrust bearing is a particular type of bearing. ...

References

  1. ^ Sobel, Dava (1995). Longitude. London: Fourth Estate, pg. 103. ISBN 0-00-721446-4. “A novel antifriction device that Harrison developed for H-3 survives to the present day - ...caged ball bearings.” 
  2. ^ Speer, Albert (1970). Inside the Third Reich. New York and Toronto: Macmillan, pp. 331-347. 

For the son of Albert Speer, also an architect, see Albert Speer (the younger). ...

External links

  • Animated 3D-model of ball bearing, explaining rotation, can be viewed in most browsers
  • Various 3D CAD models and 2D CAD drawings from various manufacturers can be downloaded from 3D ContentCentral for use in all major CAD systems
  • Pacific Bearing (a manufacturer of linear motion bearings and linear plain bearings)
  • igus plastic ball bearings

  Results from FactBites:
 
ball bearing,ceramic ball bearing,radial ball bearing manufacturer and ball bearings,ceramic ball bearings,radial ball ... (125 words)
As a professional ball bearings, ceramic ball bearings, radial ball bearings manufacturer, exporter, supplier and factory in China.--Cixi Golden Star Bearing Co.,Ltd. is an ISO 9001 certified company specialized in producing standard and non-standard bearings, ball bearing, ceramic ball bearing, radial ball bearing with ball and roller types.
With technical innovations and upgrade manufacture equipment, Our GLD brand bearings could cover a wide quality range, which of those are used worldwide in variety of industries.
We can provide you our products, ball bearings, ceramic ball bearings, radial ball bearings with our own brand and with OEM services.
Self-adjusting ball bearing cage - Patent 4653938 (1397 words)
The ball bearing assembly of claim 1 wherein the apexes of adjacent ones of said apertures are oriented in alternate directions.
Ball bearings have been in use for many years to reduce friction between a first rotating member, such as a wheel, and a second member, such as a shaft, which may be stationary or may be rotating at a different rate than the first member.
A specific object of the present invention is to provide ball bearing asseablies wherein the cage apertures are formed to engage the balls at an angle to the path of movement of the balls.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m