Related Resources: calculators

Flat Ring Thrust Bearing Moment Resistance Calculator

Flat Ring Thrust Bearing Frictional Moment Resistance Calculator

Step thrust bearings or pivots may be used to resist the end thrust of shafts. Let L = total load in the direction of the shaft axis and f = coefficient of sliding friction.

Figure 1, Flat Ring Bearing

Preview: Flat Ring Thrust Bearing Frictional Moment

For a ring-shaped flat step bearing such as that shown in figure 1 (or a collar bearing), the moment of thrust friction

Eq. 1

${\displaystyle M=1/3fL\frac{(D^3-<!--\; -\; -->d^3)}{(D^2-<!--\; -\; -->d^2)}}$

The value of the coefficient of sliding friction is 0.08 to 0.15 when the speed of rotation is very slow. At higher velocities when a collar or step bearing is used, f = 0.04 to 0.06. If the design provides for the formation of a load carrying oil film, as in the case of the Kingsbury thrust bearing, the coefficient of friction has values f = 0.001 to 0.0025.

Where oil is supplied from an external pump with such pressure as to separate the surfaces and provide an oil film of thickness h (Figure 1) the frictional moment is

For a flat circular step bearing,

Eq. 2

d = 0

${\displaystyle M=1/3fLD}$

Eq. 3

${\displaystyle M=\frac{Zn(D^4-<!--\; -\; -->d^4)}{(67x{10}^7)h}}$

Eq. 4

${\displaystyle M=\frac{\mathrm{\pi <!--\; \pi \; -->}\mathrm{\mu <!--\; \mu \; -->}\mathrm{\omega <!--\; \omega \; -->}(D^4-<!--\; -\; -->d^4)}{32h}}$

where D and d are in inches, µ the absolute viscosity, ω the angular velocity, h is the film thickness, in, Z is viscosity of lubricant in centipoises, and n is rotation speed, r/min. With this kind of lubrication the frictional moment depends upon the speed of rotation of the shaft and actually approaches zero for zero shaft speeds. The thrust load will be carried on a film of oil regardless of shaft rotation for as long as the pump continues to supply the required volume and pressure

Source:

Marks Standard Handbook for Mechanical Engineers

Related

• Bearing Life Formula Based on Speed, Load and Hardness, Ball Bearings, Radial Bearings, Thrust Bearings Ball Bearings life is related to load and speed of rotation, and this relationship must be considered when selecting bearings for various speed and life requirements.
• Bearing Types and Application Design, Ball Bearings, Roller Bearings, Thrust Bearing Type Description Friction Stiffness † Speed Life Notes Plain bearing Rolling element bearing Jewel bearing Fluid bearing Magnetic bearings Flexure bearing
• Bearing Types and Representation - Ball Bearings, Roller Bearings, Thrust Bearings, Needle Bearings Bearing Types and Representation - Ball Bearings, Roller Bearings, Thrust Bearings, Needle Bearings.
• Bearing Materials Review The most common material used to produce the load carrying components in precision ball bearings, roller bearings, and tapered roller bearings is 52100 chrome steel.
• Bearing Selection, Comparison and Application , Ball Bearings, Radial Bearings, Thrust Bearings, Needle Bearings Bearing Type Pure Radial Load Pure Axial load Combined Load Moment Load High Speed High Running Accuracy
• Force Analysis Four Point Contact Ball Bearings Four point contact ball bearings are capable of resisting radial, thrust, and moment loads, it is ordinarily subjected to a combination of two or more of these loads wherever it is applied.
• Precision Bearings Applications This class of bearings which the bearings components are manufactured to extra tight tolerances for use at high speeds, radial and thrust loads.
• Thrust Ball Bearings Magnitude of Life Ratings Use the following equation to calculate the magnitude of life rating .
• Thin Section Bearings Application Considerations There are three types of thin-section bearings: radial contact, angular contact, and four-point contact bearings.
• Thrust Chart Thrust is a reaction force described quantitatively by Newton 's second and third laws .
• Flat Thrust Plate Bearing Design Equation and Calculator Fluid thrust bearings contain a number of sector-shaped pads, arranged in a circle around the shaft, and which are free to pivot.
• Step Thrust Plate Bearing Design Equation and Calculator
• Tapered Land Thrust Plate Bearing Design Equation and Calculator
• Tilting Pad Thrust Plate Bearing Design Equation and Calculator
• Kinematic Viscosity Equation Application
• Oil Viscosity Review
• Dynamic Viscosity
• Kinematic Viscosity Table Chart of Liquids
• Viscosity of Hydraulic Fluid
• SAE J300 Motor Oil Viscosity Classification and Properties