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Polymer Rolling Element Bearings: Deep Groove Ball Bearings


Polymer Roller Bearings

BallBearing-animation -CC licensing
Working principle for a ball bearing 
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Radial Deep Groove Ball Bearings (also known as Conrad bearings) are some of the most commonly used ball bearings.  In deep groove ball bearings, the dimensions of the raceways are almost the same as the dimensions of the balls.  The grooves consist of circular arcs with a radius just a little bit larger than the ball radius.  The groove depth is typically ¼ of the ball diameter.  This geometry of the bearing to carry radial, axial, and combined loads.  However, they are used when the primary load is going to be radial.  Its ability to carry an axial load depends on how much clearance there is in the bearing after installation: if the balls are able to contact the groove at an angle, then they can support a radial load.

plastic-bearing-double-rowYou can find them with either single or double rows. Double rows work well supporting moment loads that may be acting on the shaft. These bearings are usually not separable, and the raceway is continuous.  They are also not self-aligning, so it is important that they be correctly aligned when they are installed.  Also note that even if they are not going to be lubricated, deep groove bearings are going to need some type of seal or shield to protect them from contaminants that will compromise both their performance and life span.

 

More information on polymer bearings from Advanced EMC Technologies:

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What is a Rolling Element Bearing?


Anatomy of a Rolling Element Bearingroller-element-bearing-advanced-emc

A rolling element bearing (which is a type of anti-friction bearing) involves the motion of two surfaces separated either by rollers or balls (the rolling elements) whose primary purpose is to reduce friction.  The typical rolling element bearing will consist of

(a) an inner race,
(b) an outer race (which together form the raceway),
(c) the rolling elements between them, and
(d) usually some type of cage (also known as a separator or retainer) to hold the rolling elements in place and prevent them from contacting each other. 

The only kind of rolling element bearing that does not have a cage is a called a full complement bearing.  The inner and outer race will have a groove in them, in which the rolling elements rest.  

Here are some additional excellent posts on bearings and bushings from Advanced EMC Technologies:

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