Compound gear train ratios and how to assemble gears?

In summary, a new member of the Physics Forum is seeking help with a project to construct a truck for a torque/speed test. The project involves using a small 1.5v/3v motor and achieving a gear ratio of 1/256 using a gear kit with one driver gear and six compound gears. Through calculations, it is determined that stacking two compound gears on each shaft can achieve the desired gear ratio. The member has successfully solved the problem and is now moving on to the speed-torque test.
  • #1
unseenfootage
2
0

Homework Statement



Hello fellow Physics Forumers

My first post and , hopefully not my last. I've been lurking for a long while and the tempo has increased since I started my 1st year engineering course last semester.

So I decided to register today as I have a bit of a puzzle.

We have a project to construct a truck which will be used in a torque/speed test.

First we have to do a speed - torque test of a small 1.5v/3v motor using a gear ratio (output shaft speed/motor speed) of 1/256.

I have the following kit:

http://www.mfacomodrills.com/gearboxes/multiratio.jpg

The motor is 1.5-3.0v with 8200 rpm and 14000 rpm respectively.

The driver gear has 12 teeth.
There are 6 compound gears with 48 outer and 12 inner teeth.
Two shafts , one with pulley
Assembly kit.

My question is how to achieve the gear ratio (output shaft speed/motor speed) of 1/256, with what I have?

Kind regards.

Homework Equations


Gear ratio = (No. Teeth on gear B/No. Teeth on gear A) * (No. Teeth on gear D/No. Teeth on gear C) * (No. Teeth on gear F/ No. Teeth on gear E) * (No. Teeth on gear H/No. Teeth on gear G).Gear A is the driver gear with 12 teeth. The rest are compound gears with 48 outer and 12 inner teeth.

The Attempt at a Solution



48/12 * 48/12 * 48/12 * 48/12
= 4 * 4 * 4 * 4
=256

This appears to be the solution, except I only have two shafts and the assembly plate seems to have only space for two shafts.

Is there a way of assembling it (maybe 2 gears per shaft) which might work?

Kind regards...

Homework Statement


Homework Equations


The Attempt at a Solution

 
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  • #2
Solved, by myself.

I stacked two compound gears on each shaft...One green and one orange.

The orange ones are fixed to the shift and the green ones are free.

So instead of all the gears positioned side by side on four different shafts in a line, I have only two shafts with two gears stacked on each.

Thanks anyway.

Now for the speed torque test.
 

1. What is a compound gear train ratio?

A compound gear train ratio is the ratio between the input and output angular velocities of a compound gear train. This means that it is the ratio of the number of rotations of the input gear to the number of rotations of the output gear.

2. How do you calculate the compound gear train ratio?

The compound gear train ratio can be calculated by multiplying the individual gear ratios of each gear in the train. This means that the ratio is equal to the number of teeth on the output gear divided by the number of teeth on the input gear, multiplied by the ratio of each intermediate gear in between.

3. What is the purpose of using a compound gear train?

A compound gear train allows for a larger range of gear ratios compared to a simple gear train. This means that it can achieve higher or lower speeds and torques, depending on the configuration of the gears. It also allows for more flexibility in designing mechanical systems.

4. How do you assemble gears in a compound gear train?

To assemble gears in a compound gear train, start by attaching the input gear to the input shaft. Then, attach the intermediate gears to their respective shafts, making sure they are properly aligned and meshing with the adjacent gears. Finally, attach the output gear to the output shaft and ensure that all gears are securely fastened.

5. What are some common mistakes when assembling gears in a compound gear train?

Some common mistakes when assembling gears in a compound gear train include not properly aligning the gears, using gears with different numbers of teeth, and not securing the gears tightly enough. It is important to carefully follow the gear train diagram and double check all gear ratios to avoid these mistakes.

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