Technical Information
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Flat race, flat seat bearings consist of two flat washers and a ball retaining assembly. They are used when
the ball retainer assembly must carry thrust loads without restraining shaft oscillations or flexures. They
work well with light loads and are very economical.
Grooved race, flat seat bearings are the most common type of thrust ball bearing. They consist of a shaft
mounted small bore washer, a large housing mounted bore washer, and a ball retaining assembly. Grooved
race bearings have a load bearing capacity approximately 4 times greater than flat race bearings.
Banded thrust ball bearings are self-contained, have grooved races, have a stationary and rotating face
with full ball complement, and are encased in a containing band. These bearings are most commonly used
where the bearing's outer circumference must be protected from contamination, for blind installation, or
where separating forces cause substantial axial motion of bearing components.
Aligning grooved race bearings are a variation of grooved race bearings, and are available in single and
double acting types. Aligning members compensate for initial misalignment due to shaft deflection or
mismatch, while allowing uniform distribution of the load through the bearing. The double-acting type carries
thrust in both directions.
Linear Bearings are most commonly used in linear motion applications. This type of bearing is used when
loads are to be supported as the bearing rides back and forth along a shaft. Each raceway holds balls in
rolling contact between the shaft and inner bearing race of the bushing. The remaining balls recirculate
freely in the back side of the clearance in the ball train sleeve. A retainer is usually provided so that when
the bearing is removed from the shaft the balls stay in place. Linear bearings are as easy to install as a plain
bearing, while utilizing the advantages of rolling contact. Among the important factors when considering
load capacity of a linear bearing system are life expectancy, shaft hardness, and load orientation with respect
to the ball trains. Typically, if a lifetime of more than 2,000,000 inches is required, or if a shaft hardness of
less than Rc 60 is specified, then the load-carrying capacity of the bearing system will be reduced.
Linear Bearings are the most commonly applied bearing type in linear motion systems. Clearly, many
applications involve using two sets of double linear rails, with two bearing blocks on each rail. In this case,
the load found on each bearing block is of interest when selecting the bearing components. There are three
basic orientations for the bearing system and loads, and each case is represented as follows.
Horizontal Translation with Normal Load: when a normal load is applied to a horizontal bearing system,
the loads on each bearing are found by using the following equations. The equations still apply if the load is
acting inside of the carriage mounting surface area. The orientation of the applied load with respect to the
bearing system is the important feature to consider. This means that these equations can still be used even
if the orientation of the translation is not horizontal, as long as the load to bearing relationship is preserved.
Load-carrying balls
Recirculating balls
in clearance
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