Design of Spiral Retaining Rings

Calculation of thrust load

You can calculate the allowable thrust load of ring in the following formula.

Ps=(D・T・Ss・π)/K
Ps:Allowable thrust load(N)
D:Shaft or hole diameter(mm)
T:Thickness of ring(mm)
Ss:Shearing force of material(MPa)
K:Factor of safety(dead load・3 dynamic load・5 impact load・12)

Calculation of stress in the case of attaching

You can calculate stress in the following formula when you attach ring in the shaft or the hole.
We recommend you to assume this stress should be lower than yield point of the material.

For hole S=(C・E・H)/[Dn・(1-C)]
For shaft S=(C・E・H)/[Dn・(1+C)]
S:Stress at the time of attaching(MPa)
Dn:Circle diameter of ring(mm)
C:Changing rate of the maximum or minimum diameter, and hole and shaft.
E:Young's modulus(MPa)
H:Width of ring(mm)

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