Manufacturer | Rating Life, Revolutions | Weibull Parameters Rating Lives | ||
x0 | θ | b | ||
1 | 90(106) | 0 | 4.48 | 1.5 |
2 | 1(106) | 0.02 | 4.459 | 1.483 |
Tables 11-2 and 11-3 are based on manufacturer 2.
11-1 A certain application requires a ball bearing with the inner ring rotating, with a design life of 25 kh at a speed of 350 rev/min. The radial load is 2.5 kN and an application factor of 1.2 is appropriate. The reliability goal is 0.90. Find the multiple of rating life required. xD, and the catalog rating C10 with which to enter a bearing table. Choose a 02-series deep-groove ball bearing from Table 11-2, and estimate the reliability in use.
The multiple of rating life of the bearing.
The catalog rating of the bearing.
The reliability of the bearing.
Answer to Problem 1P
The multiple of rating life required is
The catalog rating of the bearing is
The reliability of the bearing is
Explanation of Solution
Write the expression for multiple of rating life for bearing.
Here, multiple of rating life for design is
Write the regression equation for bearing load life.
Here, the bearing load for design is
Write the equation for bearing life.
Here, the rating life in hour is
The following figure shows the relationship between bearing load and dimensionless life in terms of logarithmic values.
Figure-(1)
Write the equation for reliability along a constant load line
Here, the characteristic parameter is
Write the expression for catalog rating in terms of application factor.
Here, catalog rating is
Conclusion:
Substitute
Substitute
Thus, the multiple of rating life of bearing is
Substitute
For ball bearing, the value of constant
Substitute
Substitute
Refer table 11-2 "Dimensions and Load Rating of Ball Bearing”, to obtain the ball bearing at catalog rating of
Thus, the catalog rating of the bearing is
Substitute
Substitute
Substitute
The reliability of the bearing is
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Chapter 11 Solutions
SHIGLEY'S MECHANICAL ENG.DESIGN W/CODE
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