Anti-backlash slewing bearing/ pinion set-up 1

[frugby1]

I am working on a design for the medical industry, requiring low backlash in my set-up (below 6arcmin).
At this point, the part is rotating on a slewing bearing, with external teeth, 4.5 Module. A pinion cut on the output shaft of a worm gearbox make the rotation possible... but the backlash is too high, and increases over time.

Is it possible to find an antibacklash pinion that could carry 2500 ft.lb (on 1 3/4 width), with a 4.5 module?
What is the biggest module that we can find on antibacklash gears? Everything I saw, was up to 24 pitch,

Any other idea is welcome.
Thanks.

 

[eromlignod]

Can you design in an adjustable or spring-loaded center distance into the gear housing? Sometimes this is done with a mounted bearing bolted through slotted holes and positioned with a jackscrew.

Don
Kansas City

 

[dimjim]

What is the material of the worm and gear?

 

[unclesyd]

May I ask what equipment in the medical field requires that that type of power input?

Most equipment I've seen including some large scanning and radiological equipment use some type of rotary table or rotary positioner.

 

[dimjim]

The medical equipment that I have seen use
HTD belts and pulley and special hobbed or
shaped gear to mate with the belt.

 

[frugby1]

The high torque on the gears comes from the stopping distance requirement.
I looked already at belt, but the size would never fit in the design.
The gears are made of Hardenned 1045 for the bearing, and 4340 for the pinion.
I forgot to precise yesterday that we have a 1:8 ratio.

Thanks,
David.

 

[dimjim]

Can you develop or incorporate an adjustable
center distance in this design? I cannot imagine
a spring loaded anti backlash pinion able to
take that force. I was certain that your ratio
was high. I assume it is the gear that is wearing
and not the pinion. You might be able to
use another pinion but have it back loading
the gear a small amount or enough to overcome
the backlash problem. I assume you are using
a long addendum pinion design. How hard is the
4340 pinion and the 1045 gear.

 

[volpegrigia]

There are several methods to eliminate the backlash in gear drives. In sler\wing rings appications you should contact the company Rothe-Erde (their affiliate in USA is called Rotek, I believe and it is located in Ohio). They have the most experience with slewing ring drives and they can certainly help. As to Drive systems for slewing rings you can contact RRUSA

http://www.rrusainc.com/

or Atlanta

http://www.atlantadrives.com/.