Vernier Dial Planetary Reduction Drive

[CoreyB]

Here's a project I just completed. It's a Vernier dial ball bearing planetary reduction drive. It will be used to
perform fine adjustments of air variable capacitors in amateur radio applications. The end caps and internal
races are done in 12L14 steel and the main body is aluminum. The central shaft is also steel and the carrier
is done in brass. I used a Smithy 1324 with a DRO to create all of the parts and to drill and tap all of the holes.
It took me a bit of time to figure out how to properly create the trough in the center shaft and then a bit more
time to figure out how to make it work smoothly.

--Corey

 

[rwm]

Wow. That looks great and it is a really clever application for such a drive. I confess I don't see exactly how it works though?
Robert

 

[brino]

Is it like most planetary drives except here, instead of gears, the balls are a "rolling friction element" ?

If so, I would think the tolerances would need to be amazing!

-brino

 

[CoreyB]

Is it like most planetary drives except here, instead of gears, the balls are a "rolling friction element" ?

If so, I would think the tolerances would need to be amazing!

-brino

Yes, rolling friction but the tolerances are quite easy to achieve. The races are simply 45 degree angles cut
into steel to form a race. This can be done with a high quality counter sink and then polished out to a mirror finish with aluminum clothe and finally a good metal polish.

—Corey

 

[eugene13]

HAPPY TURKEY DAY, in my back yard at 8:30 this AM

 

[Pietro]

Ecco un progetto che ho appena completato. È un riduttore planetario con cuscinetto a sfera con quadrante Vernier. Ci sarà abituato
eseguire regolazioni fini dei condensatori variabili in aria nelle radioamatoriali. I tappi terminali e interni
le corse sono in acciaio 12L14 e il corpo principale è in alluminio. Anche l'albero centrale è in acciaio e il supporto
è fatto in ottone. Ho usato uno Smithy 1324 con un DRO per creare tutte le parti e per forare e maschiare tutti i fori.
Mi ci è voluto un po' di tempo per capire come creare correttamente il trogolo nel pozzo centrale e poi ancora un po'
tempo per capire come farlo funzionare senza intoppi.

--Corey

Here's a project I just completed. It's a Vernier dial ball bearing planetary reduction drive. It will be used to
perform fine adjustments of air variable capacitors in amateur radio applications. The end caps and internal
races are done in 12L14 steel and the main body is aluminum. The central shaft is also steel and the carrier
is done in brass. I used a Smithy 1324 with a DRO to create all of the parts and to drill and tap all of the holes.
It took me a bit of time to figure out how to properly create the trough in the center shaft and then a bit more
time to figure out how to make it work smoothly.

--Corey

Thanks Corey, very interesting. Do you have a drawing with dimensions to send us?

 

[rwm]

Yes. I am still trying to figure out how that works without any type of carrier following the balls?
Edit: Are there 3 holes in the brass shaft? If so that would make sense!

 

[Pietro]

The functioning of the mechanism can be guessed by observing a common ball bearing, in which the ball ring rotates at half the speed of the central ring. In the proposed project, the ring is made up of the yellow brass tube, which can be seen in the photo and which certainly has holes which it needs to be pushed by the rolling spheres. The role of the central ring is played by the central axis, visible below.
To work well the balls must be very adherent to the rotation grooves, and normally this is obtained by means of a spring, which however I do not see

 

[rwm]

The spring is in the pic. It's a wave spring.

 

[Pietro]

yes, you're right, I missed it