Same output frequency, different input frequencies?

[bernardirafael]

Hello dear friends,

I am wondering if there's a way to solve a problem I'm facing. I want to create a crank mechanism that runs at a steady frequency (18Hz). However, the electrical engine that will run it will rotate at different speeds. Is there any way to make it? Any mechanism that independently of the input rotation frequency the output is always the same?

Thanks in advance!

 

[tbuelna]

I'm not clear on exactly what output motion you want from your crank mechanism. Do you want a reciprocating linear output motion, like that from a scotch yoke or crank/conrod? Or do you want a rotary output motion?

If you want a constant frequency reciprocating linear output motion from some crank mechanism using a variable rpm drive motor, then the easiest approach would be to simply install a CVT between the motor and a conventional crank mechanism. There are various types of CVT readily available (belt, chain, traction, hydrostatic, etc) that should work.

There are also several types of ratcheting CVT that adjust rpm between the input and output shafts using a variable stroke crank mechanism. Here is a video of how these CVTs function:

https://youtu.be/G9-N-nIqc4g

Hope that helps.

 

[spigor]

Here's one I find interesting:

http://voith.com/corp-en/drives-tra...ns/vorecon-variable-speed-planetary-gear.html

 

[drawoh]

bernardirafael,

You could design an escapement and pendulum like on a clock, then mount your motor through a fluid coupling as on an automatic car transmission. A simpler solution is to mount a flywheel to your output, forcing the motor to run at steady speed.

--
JHG

 

[Strong]

The wind turbine-generator industry has this problem. Here are sample solutions:

Electrical Solutions

http://ecee.colorado.edu/~ecen2060/materials/lecture_notes/VariableSpeedWind.pdf

Mechanical Solution

https://www.researchgate.net/public...transmission_for_variable_speed_wind_turbines

Walt