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Recently I had a disturbing conversation with a colleague here at the office. During the conversation, it became clear to me that my co-worker -- a really
intelligent guy whom I respect a lot -- had no idea how even the most simple electric motor works.
Mounted ball bearings are everywhere in industrial applications. They serve critical roles in keeping a manufacturing operation running smoothly and in ensuring that equipment functions properly and reliably. So why might it be advisable to spend significantly more for a dimensionally
comparable bearing from one supplier versus another?
For the most accurate measurements,
miniature and instrument ball bearing
dimensions should be measured with a
calibrated air gauge. A good second option is a calibrated optical comparator. On occasion, it may be necessary to use a calibrated, hand-held micrometer to double-check a measurement or for simple verification while working in the field.
The history of railroading is a saga of epic proportions: North meets South; Ocean meets Ocean. Track and trains and the locomotives that power them have long held Americans' fascination and fancy.
Seal design engineers and end users are continually seeking improved sealing
systems and materials. This paper describes the potential of a new thermoplastic polyurethane (TPU) material to deliver improvements in pressure, speed and temperature capability, which are presented as comparisons to proven industry
standard materials. Performance is demonstrated by virtue of test bench
results of seals made from MDI-, PPDI- and NDI-based materials.
At first glance, ball bearings are
relatively simple mechanisms. However,
an analysis of their internal geometries
reveals that they are quite complex. For
example, the ball to raceway conformity,
the radial play, and the number of balls all impact the ability of a ball
bearing to support loads under a variety
of conditions.
American Bearing Manufacturers Association (ABMA) Standard 9 and ISO 281 give equations for calculating
the basic dynamic radial load rating for ball bearings. These equations are based on a number of assumptions, many
of which are not valid for thin-section bearings. (Thin-section bearings are described in ABMA standard 26.2.)
Nevertheless, many thin-section bearing catalogs report load ratings based on these equations. Kaydon has developed a new method for calculating the dynamic radial load rating for thin-section ball bearings. The new method uses the contact stress and the number of stress-cycles-per-revolution to calculate the capacity. The new numbers are based on five years of actual test results. These equations can also be used to calculate the dynamic radial load rating for four-point contact ball bearings, which are not covered in ABMA standard 9 or ISO 281.