Calculating Thrust Load Capacity for Retaining Rings

Load Capacity of Retaining Rings and Grooves

Rings usually have two load statistics, thrust load capacity based on ring shear and thrust load capacity based on groove yield. The lower of these two theoretical values is the thrust load capacity of the system, because once the lower value is reached, the system will fail. In most cases, the thrust capacity of the groove is the determining (lower) value. In thrust load calculations, a safety factor is used to account for imperfections in the system. Typically a safety factor between 2 and 4 is used for calculations of thrust load capacities.

Thrust Load Capacity based on Ring Shear is the load capacity of the ring. This is the theoretical amount of load that the ring can withstand before it shears (gets cut). The theoretical value is based on the overall thickness of the ring and the shear strength of the ring material.

Thrust Load Capacity based on Groove Yield is the load capacity of the groove. This is the theoretical amount of load that the groove can withstand before it deforms and fails. The theoretical value is based on the depth of the groove and the yield strength of the groove material.

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How to calculate capacity based on Ring Shear

To calculate the theoretical thrust capacity of a retaining ring's shear strength, the equation to the left is used. The variables are: B: The diameter of the bore or shaft. t: The overall thickness of the retaining ring. Ss: The shear strength of the retaining ring material. pi: 3.14 K: Factor of safety. Typically 3 or 4.

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How to calculate capacity based on Groove Yield

To calculate the theoretical thrust capacity of a groove, the equation to the left is used. The variables are: B: The diameter of the bore or shaft. d: The depth of the groove. Ys: The yield strength of the groove material. pi: 3.14 K: Factor of safety. Typically 2 or 3.