Name: double-collar bearing torque calculations
Uploaded: 2023-09-22T11:49:30.000Z
Duration: 1 min 24 s
Channel: JoVE

Consider a double-collar bearing with a hole radius of 20 millimeters, experiencing an axial force of five kilonewtons.
Collar A, with a radius of 40 millimeters, carries 75 percent of the force, while collar B, with a radius of 30 millimeters, carries 25 percent; both collars distribute pressure uniformly.
Calculate the maximum frictional moment the bearing can resist, given a static friction coefficient of 0.3 for both collars.
Recall the expression for the required maximum frictional moment. By rearranging and substituting the values of the forces supported by both collars, the maximum frictional moment can be determined.
Next, modify the configuration by exerting an axial force of 15 kilonewtons on the bearing. Determine the minimum torque required to overcome the friction.
Using the frictional moment equation and substituting the values, the moment for both collars caused by the frictional forces can be determined.
By equating the sum of moments about the z-axis to zero and substituting the known values, the required minimum torque can be determined.

bearings: problem solving

Bearings: Problem Solving

Understanding the calculations and concepts related to double-collar bearings is essential for engineers and designers to optimize the performance of these components in various applications. By analyzing the bearing under different conditions, one can ensure that it can withstand the forces and moments experienced during operation. This knowledge enables better decision-making when designing and selecting bearings for specific purposes and configurations. Consider a double-collar bearing with specific dimensions and an axial force applied to it.
<img alt="Leverage diagram: Demonstrates torque with applied force F, arms A and B." src="/files/ftp_upload/14327/14327_PT_Figure_1v2.svg" style="text-align: center; height: 400px;" data-altupdatedat="1761830439000" data-alt="Figure 1">
To find the maximum frictional moment that the double-collar bearing can withstand, the following expression can be used:
<img alt="Static equilibrium equation M=2/3μsFA(r³A−r³)/(r²A−r²)+2/3μsFB(r³B−r³)/(r²B−r²)." src="/files/ftp_upload/14327/14327_PT_Equation_1v2.svg" style="text-align: center; height: 39px;" data-altupdatedat="1761830439000" data-alt="Equation 1">
The maximum frictional moment can be calculated by rearranging the expression and substituting the values of the forces supported by both collars.
Consider a scenario where the applied axial force on the double-collar bearing increases. To determine the minimum torque needed to overcome the friction, first calculate the moment for both collars caused by the frictional forces using the frictional moment equations and substituting the values.
<img alt="Static equilibrium formula: \(M_A=\frac{2}{3}μ_sF_A(\frac{r_A^3-r^3}{r_A^2-r^2})\) for force analysis." src="/files/ftp_upload/14327/14327_PT_Equation_2v2.svg" style="text-align: center; height: 39px;" data-altupdatedat="1761830439000" data-alt="Equation 2">
<img alt="Static equilibrium equation, \(M_B=\frac{2}{3}\mu_sF_B\left(\frac{r_B^3-r^3}{r_B^2-r^2}\right)\), formula." src="/files/ftp_upload/14327/14327_PT_Equation_3v2.svg" style="text-align: center; height: 39px;" data-altupdatedat="1761830439000" data-alt="Equation 3">
Next, equate the sum of moments about the z-axis to zero and substitute the known values. The required minimum torque to overcome the friction in the modified configuration can be evaluated.
<img alt="Static equilibrium equation ΣMz=0; formula diagram for educational use." src="/files/ftp_upload/14327/14327_PT_Equation_4v2.svg" style="text-align: center; height: 13px;" data-altupdatedat="1761830439000" data-alt="Equation 4">

Understanding the calculations and concepts related to double-collar bearings is essential for engineers and designers to optimize the performance of ...

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Friction

KEY TERMS AND CONCEPTS

double-collar bearing torque calculations

Double-collar bearing torque calculations show how friction and axial force affect bearing performance. Engineers use these calculations to test whether the bearing can handle the forces and moments it experiences during operation. This helps them choose and design bearings for specific applications and setups.

For a double-collar bearing with set dimensions and an axial force applied, the maximum frictional moment can be found with a standard expression. The equation is rearranged, and the forces supported by both collars are substituted into it. This gives the greatest frictional moment the bearing can withstand under that condition.

The same method also helps when the axial force on the double-collar bearing increases. First, the frictional moment for each collar is calculated from the frictional force equations. Then the moments about the z-axis are set equal to zero, and the known values are substituted. From this, the minimum torque needed to overcome the friction in the modified case can be determined.

Double-Collar Bearing Torque Calculations

double-collar-bearing-torque-calculations

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key terms and concepts

Learn how frictional moment and axial force are used to solve double-collar bearing problems, including maximum moment and minimum torque calculations.

Double-Collar Bearing Torque Calculations | JoVE K12

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Double-Collar Bearing Torque Calculations

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