Design of a Keyed Joint

SOM-SHEAR-05-EN

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Determine the allowable torque transmitted from the shaft to the gear through the keyed joint.

Shaft diameter 20 mm, effective key length 40 mm, key width 9 mm, key height 8 mm, keyway depth in the shaft 5 mm

Allowable stresses:

- for the shaft and gear material τ_allow=144 MPa, σ_allow,loc=360 MPa

- for the key material τ_allow=120 MPa, σ_allow,loc=300 MPa

Allowable torque based on shaft strength, N·m

Allowable force in the key based on shear strength, N

Allowable force in the key based on bearing strength, N

Allowable torque based on key strength, N·m

Overall allowable torque, N·m

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About this task

This task focuses on the design of a keyed joint that transmits torque from a shaft to a gear. Students determine the allowable torque based on the torsional strength of the shaft, check the key for shear and bearing stresses, and identify the limiting torque that can be safely transmitted by the joint. The task develops practical skills in keyed-joint design, application of strength criteria, and machine element design.