Gear reduction without different sizes of gears
Feb 27, 2015 18:13:24 GMT
ivangorin21, Indigo, and 3 more like this
Post by beege on Feb 27, 2015 18:13:24 GMT
A lot of effort gets devoted to this subject, lots of "transmissions" etc.
Some of the efforts are really for shifting output from one input source at one speed to another input source running at another speed. Fair enough, it allows you to mechanically change from one input to another and change the speed of your output. Not really gear reduction since you are using different speeds on your inputs (one wheel or motor running at a different speed from another wheel or motor). But still a transmission of sorts.
It's also easy to build a CVT (constantly variable transmission) using a motor set between the output and a variable drag, usually a set of propeller blades mounted on steering motors. Also good and a very useful motor/transmission for flying vehicles in particular.
But the mental challenge of direct non loss (other than elasticity/gear slop) gearing of different ratios is rarely attacked.
I present a direct gear system, not for its practicality but just as a mental challenge.
If you watch the video and mess with the bsg you will see I have marked the output shafts with three kinds of armor and one with a decoupler. This is just to make it easier to discuss.
There is only one drive wheel in the system. It direct drives the output shaft marked with a small square of armor. Lets call that direct drive speed 1. Then it goes through a differential with one output shaft locked to double the rotation speed and sends it back to the output shaft marked with the rectangular armor so it runs at speed 2. Then I double it again and send it back to the shaft marked with the circular armor running at speed 4. This is not just to show you can double it twice but so we can do something with the 2 and 4 outputs.
Since a differential takes one input and runs two outputs whose sum of rotation speed is twice the input shaft (in our differential there is no gearing, in a real one you can change the number of teeth and vary that ratio) when we lock one of the output shafts the remaining one has to rotate at 2X the input shaft. But we can use this in another way. To state it differently in our differential the input shaft runs at half the speed of the sum of the output shafts. So we run the 2X shaft into one side (normally the output shaft) of the diff and we run the 4X into the other side the the output shaft now turns at 3X (4+2=6, 6/2=3). This is the output marked with the decoupler.
SO, if you can double or halve any rotation speed and also combine any rotations speeds your gearing output speeds are limitless although completely impractical.
But it's done with all one kind of gear. Just to show it could be done.
You know you would have bet a dollar that it could not be done. Since we did not bet ahead of time but I still did the work just send me 50 cents and we will call it even.
Some of the efforts are really for shifting output from one input source at one speed to another input source running at another speed. Fair enough, it allows you to mechanically change from one input to another and change the speed of your output. Not really gear reduction since you are using different speeds on your inputs (one wheel or motor running at a different speed from another wheel or motor). But still a transmission of sorts.
It's also easy to build a CVT (constantly variable transmission) using a motor set between the output and a variable drag, usually a set of propeller blades mounted on steering motors. Also good and a very useful motor/transmission for flying vehicles in particular.
But the mental challenge of direct non loss (other than elasticity/gear slop) gearing of different ratios is rarely attacked.
I present a direct gear system, not for its practicality but just as a mental challenge.
If you watch the video and mess with the bsg you will see I have marked the output shafts with three kinds of armor and one with a decoupler. This is just to make it easier to discuss.
There is only one drive wheel in the system. It direct drives the output shaft marked with a small square of armor. Lets call that direct drive speed 1. Then it goes through a differential with one output shaft locked to double the rotation speed and sends it back to the output shaft marked with the rectangular armor so it runs at speed 2. Then I double it again and send it back to the shaft marked with the circular armor running at speed 4. This is not just to show you can double it twice but so we can do something with the 2 and 4 outputs.
Since a differential takes one input and runs two outputs whose sum of rotation speed is twice the input shaft (in our differential there is no gearing, in a real one you can change the number of teeth and vary that ratio) when we lock one of the output shafts the remaining one has to rotate at 2X the input shaft. But we can use this in another way. To state it differently in our differential the input shaft runs at half the speed of the sum of the output shafts. So we run the 2X shaft into one side (normally the output shaft) of the diff and we run the 4X into the other side the the output shaft now turns at 3X (4+2=6, 6/2=3). This is the output marked with the decoupler.
SO, if you can double or halve any rotation speed and also combine any rotations speeds your gearing output speeds are limitless although completely impractical.
But it's done with all one kind of gear. Just to show it could be done.
You know you would have bet a dollar that it could not be done. Since we did not bet ahead of time but I still did the work just send me 50 cents and we will call it even.
