What is shear stress on the Key

In summary, the question asks for the shear stress on a key located at the interface between a shaft and a gear, assuming a uniform shear stress distribution across the key width. The shear stress is calculated by dividing the applied torque by the shaft radius and then dividing that by the product of the key width and key length. This stress is caused by both the torque transmitted by the shaft and the compressive forces acting on the key.
  • #1
Sean Trainor
3
0
Hi guys,

I'm trying to work out the following:

Assume uniform shear stress distribution across "Key" width.

What is the shear stress (psi) on the "Key" at the interface with the "Shaft"?

Torque (in-lb) = 4959
Shaft diameter (in) = 2
Key width/height (in) = 0.3
Key length (in) = 2
 

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  • #2
How could key as shown in your drawing transmit any drive forces between shaft and gear ?
 
  • #3
Nidum said:
How could key as shown in your drawing transmit any drive forces between shaft and gear ?
What do you mean?

The question above is one which was put to me while doing an online test regarding FEA software. Most questions were based on the software which was fine, but then a few questions required hand calculations. And I'm rather rusty when it comes to that since I haven't done any since uni :-)
 
  • #4
You describe a plain rectangular key . For this to work properly half of the depth of the key has to be in the shaft and half in the gear .
 
  • #5
key.jpg
 
  • #6
At the point when a key is utilized as a part of transmitting torque from a pole to a rotor or center, the accompanying two sorts of strengths follow up on the key : ... (b) Forces (F) because of the torque transmitted by the pole. These strengths produce shearing and compressive (or pounding) stresses in the key.
 
  • #7
Assuming that a key is installed as shown in Nidum's figure the key's shear line is the radius of the shaft and the key's shearing area = the key width x key length.
The amount of applied shearing force = the applied torque / shaft radius
As a result, the key's shearing stress = (torque / shaft radius) / (key width x key length)
 

Related to What is shear stress on the Key

1. What is shear stress on the key?

Shear stress on the key refers to the tangential force per unit area that is applied to the key, resulting in a deformation or movement of the key along its length. It is a measure of the resistance of the key to shearing forces.

2. How does shear stress affect the key?

Shear stress can cause the key to experience bending or twisting, which can lead to fatigue and failure over time. It is important to consider the shear stress on a key when designing mechanical systems to ensure the key can withstand the expected forces without breaking.

3. What factors influence shear stress on the key?

The amount of shear stress on a key is influenced by the applied force, the surface area of the key, and the material properties of the key. Additionally, the fit and alignment of the key in the keyway can also affect the amount of shear stress.

4. How is shear stress calculated on a key?

Shear stress on a key can be calculated using the formula: shear stress = applied force / cross-sectional area of the key. This calculation can help determine if the key is strong enough to withstand the applied forces.

5. What are some common materials used for keys that can withstand shear stress?

Common materials used for keys that can withstand shear stress include steel, hardened steel, and titanium. These materials have high tensile strength and can handle the forces and stresses associated with shear stress on a key.

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