Gearmotor Sourcing and Bearing Selection

[twelveofive]

Hi Guys,

I am trying to source a Gearmotor or a motor and a gearbox for a small sand mixer. I have an 230 volt 3-phase power supply available or I could set up a DC power supply. I am looking for a relatively lightweight gearmotor assembly that can output approximately 350 N.m of torque at 15-25 rpm. Also, I am hoping to flange mount the gearbox on the top of the mixer. I am having trouble finding a product with these specification, does anyone have any suggestions on where to find a motor/gearbox like this in North America? Any reliable suppliers that have a relatively quick shipping time?

Additionally the mixing cylinder has an internal diameter of 6.75 inches and will be filled with 4 kilograms of sand.

Also, I estimate that the shaft size will be 1 or 1.25 inches and am wondering what kind of bearing I should be putting in the top of the mixer? Any experiences with similar situations?

I attached a rendered image of the setup.

Thanks, I appreciate any suggestions you might have.

 

[tygerdawg]

Most gearmotor manufacturers have an almost infinite range of gear / torque / horsepower / mounting configurations. Major brand names for "industrial" (NOT hobby)units that I can remember are SEW-Eurodrive, Dodge, Regal-Beloit (formerly Emerson), Nord. Quite a few more are out there.

All manufacturers have Engineering Guides for configurations & sizing, also catalogs. But because of the "infinite variety" many catalogs are necessarily incomplete. Specific design configurations can be obtained with assistance of the manufacturer's Tech Support / Applications Engineering team typically.

After configured, units are usually purchased from distributors like Motion Industries, Applied Industrial Technologies, & Kaman.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[3DDave]

Yes on contacting the makers. Their on-line and catalog info is generally bad. They have too many options and customizations to depict well.

Concentrate on getting the operating environment range you expect this to work in; this will have the largest effect on the motor selection.

 

[BrianPetersen]

We used SEW-Eurodrive where I worked last, and they had software that would produce a CAD drawing of whatever gearbox you chose.

Now, as for that shaft ... presumably it has the mixer blades on it. You have to think about not over-constraining the way the shaft is located - because that will overload bearings if alignment isn't perfect, and the type of apparatus that you're building doesn't do perfect alignment.

Options:
- Mount the mixer blades directly to the gearmotor output shaft and have NO bearing on the other end. For the small thing that you are building, you could likely get away with this.
- Mount the mixer blades to pillow-blocks (self-aligning bearings) at the top and bottom of your mixer enclosure with a shift sticking out, and then use a shaft-mounted gearmotor (basically a hollow output that goes overtop of your shaft with a key) and a torque-arm mounting of the gearbox housing (so that the gearbox mounting transmits the torque reaction only, but the shaft does the rest of the orienting).

The bottom bearing is going to have an unpleasant operating environment. Not having that bearing seems like an attractive option.

 

[tbuelna]

For something like a mixing machine, you might consider using a V-belt drive between the drum and gearbox. This will provide some overload protection for the motor and gearbox.