How Do You Solve a Complex Epicyclic Gearbox Assignment?

[dstealth]

Hi all, I'm Chris, a first time poster!

Currently stuck on an assignment question for my mechanical engineering course. The question is shown in the picture below. The capital T refers to 'teeth', as in 20T is 20 teeth on that particular gear. Ignore the little arrows with P and S - that is just me labeeling up the planetary and the sun gears. I answered a previous question on epicyclic gearboxes no problem but we have not been taught how to answer one this complex:-

Any pointers?

Thanks in advance.

 

[rock.freak667]

The question is essentially asking for the ratio of the output speed to the input speed.

If I remember correctly the module m= D/T and for meshing gears, the modules are the same.

 

[dstealth]

The question is essentially asking for the ratio of the output speed to the input speed.

If I remember correctly the module m= D/T and for meshing gears, the modules are the same.

Shown in the pictures is the previous question which that question is based upon, along with my working out. I calculated a 6:1 reeduction ratio for the first question and a fixing torque of 25.46 Nm. I just don't know how to do the second question of the 'modified' gearbox that I posted in the first post.

Thanks

 

[dstealth]

I'm sure the working out is simple, it's just we haven't covered any examples like this in the lesson.

 

[DeeNos]

Hi Chris,

As a fellow scientist, I understand the struggle of complex engineering problems. The key to solving this question is to break it down into smaller parts and use the principles of epicyclic gearboxes to solve each part individually.

First, let's identify the different gears in this system. The sun gear has 20 teeth, the planet gear has 40 teeth, and the ring gear has 60 teeth. Based on this information, we know that the gear ratio between the sun gear and the planet gear is 1:2 (40/20) and the gear ratio between the planet gear and the ring gear is also 1:2 (60/40).

Next, we need to determine the overall gear ratio of the system. This can be done by multiplying the individual gear ratios. In this case, the overall gear ratio would be 1:4 (1:2 x 1:2).

To determine the direction of rotation, we can use the right-hand rule. If the sun gear is rotating clockwise, the planet gear will rotate counterclockwise and the ring gear will rotate clockwise. This can also be verified by looking at the arrows labeled P and S in the picture.

I hope this helps you get started on solving the complex question. Remember to apply the principles of epicyclic gearboxes and break down the problem into smaller parts. Good luck with your assignment!