Key Design
Key Design |
W_{t}=2T/D_{shaft}
Where:
Wt is the value of tangential force to be calculated at locations of interest
T is the torque value at the location under consideration
D_{shaft} is the shaft diameter at the location under consideration
Bearing Stress:
Shear Stress:
Where:
W_{t} is the tangential force
a is the side of the square key
l is the length of the key (to be solved)
S_{y} is the yield strength of the key material selected
S_{sy} is the shear yield strength of the key material = 0.5S_{y}
n is the safety factor
The final value of the length (l) of the key will be the larger of the two values calculated for each location. Generally, key sizes must fall within the following range by length:
If the calculated key length exceeds 1.5D_{shaft}, and you cannot strengthen the key material further, use two keys placed at 180° at the same section