Gears 3

[partha707]

I would like to know the exact importance of the following in gear manufacturing.

1) Crowning
2) Tip relief
3) root Relief
4) Pressure Angle
5) Shot peening

could anybody calrify me.

 

[carburized]

partha707

1. Crowning is used in heavy loaded application. Under load when teeth deflect, crowning helps to make a full contact of face width. Hence, you are carrying the load on full face width.

2. Tip relief: It is there to have a smooth transition from tooth to tooth. This also helps to maintain the active profile so you could use the better part of the gaer tooth.

3. Root relief: You need to relieve the root so that when teeth are going out of mesh, they do not unnecessarily stress the teeth by binding.

4. Pressure angle: Line connecting PA's on both pieces is the line of action where all the cotact takes place. Usually higher the angle, bending capability is increased. All of our gears used in gearboxes are cut with 25 deg pA.

5. Shot Peening: Is done on the gears to impart compressive stresse in the root of gear teeth. I think this is more common in Automotive industries or in application where high bending strength is needed. Usually teeth fail in bending due to tension in the root area. So, by introducing more compressive stresses this negates those tensile stresses.

I hope this helps.

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Ravi