# Refreshing help needed with calculation of torque of gear wheel

1. Jun 6, 2012

### Fjolvar

Hello,

I'm working on calculating a torque value for an engineering project at a new internship I started. Basically there is a spinning gear wheel similar to the picture I posted below (but thicker/cyclindrical), and I need to calculate the force or torque applied on a locking bolt that will suddenly engage at about 1/2*r of the gear bringing it to a complete stop.

http://thehobbyshop.co.za/images/LOWER_GEAR_WHEEL.jpg [Broken]

The radius of the wheel (which is cylindrical in shape) is approximately 1.5cm with a length of about 2.5cm. I'm given the RPM which is a constant speed, so from that I can calculate the angular velocity. After the bolt engages, the velocity will change to zero creating a deceleration that I can plug into the torque formula T= I*a.

Would I have to then calculate the moment of intertia in order to solve the equation, and if so, how would I approach this? I've only solved inertia problems with ideal shapes.. not oddly shaped gears. Any help would be greatly appreciated! Thanks in advance..

-Ryan

Last edited by a moderator: May 6, 2017
2. Jun 6, 2012

### Fjolvar

So basically I just need to calculate the torque of a spinning gear wheel. Any ideas from anyone?

3. Jun 6, 2012

### Mantaray

To calculate moment of inertia, can you not see the gear wheel as a sum of ideal shapes? You could disregard the teeth and see the outer rim as a ring, the inner part as a disc, and the connections between them as rods or planes.