Page 67 - Rollingbearings

Performance and operating conditions
B 1 – B 8

B 1 Performance and operating

conditions

The irst step in the bearing selection process limits of the range may be important,
is to understand and document: whereas in others, only the lower or the
upper limit may be
• the required performance In order to optimize a design, you may
• the operating conditions and assumptions need to loop through various steps of the
of them bearing selection process To minimize these,
• any other application prerequisites review and prioritize any application pre­
requisites, such as:
An application can set various requirements
on the bearing solution Common factors • available radial or axial space
include: • shaft diameters deined by shaft strength
requirements
• bearing life • lubricant choice determined by other
• speed capability and ability to withstand components in the application Performance and operating conditions
applied acceleration levels
• precision of the radial and axial position of The relationship between principal operating
the shaft conditions, application requirements and
• ability to cope with low or high tempera- various aspects of a bearing arrangement’s
tures or temperature gradients design are shown in Factors to consider
• generated noise and vibration levels when translating operating conditions and
application requirements into a bearing solu-
The relative importance of these performance tion, page 66 The lists are not comprehen-
factors can inluence the nature of the path sive and you may have to consider other B.1
you take through the steps of the bearing factors and interrelationships, like cost and
selection and application analysis process. availability, when striving to obtain a robust
You should evaluate the operating condi- and cost- effective solution
tions in as much detail as possible. The most
important operating parameters are:

• load
• speed
• temperature
• lubricant and lubricant cleanliness

Usually these can be determined from
physical and mechanical analysis of the
application, or from experience with similar Use the Application data sheet, at the
applications. Make sure that any assumptions end of this catalogue, to help when con-
made are clearly documented. tacting the SKF application engineering
Operating conditions typically vary over service.
time, e.g. in variable speed applications or
because of seasonal temperature changes
or increased output power. The range of the
variation is important. In some cases, both

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