Prototype Small Wheeled Shooter

[Paul Copioli]

All,

There are several items that contribute to heat in a VersaPlanetary gearbox. The #1 thing that is different than other gearboxes you are used to is the thin wall of the ring gear section. The ring gear is aluminum and very thin so it conducts the heat very quickly and gets hot quickly. In addition, the thermal mass of the aluminum is less than the steel gears and bearings so it will get hotter much faster than the internal steel gears.

Also, the output shaft is also aluminum to that thing gets pretty hot, too.

The BAG motor has the same internal construction as a CIM motor and that is why it is able to dissipate heat in a similar way. It does not rely on convection cooling like a RS550, RS775, or AM-9015 so it is happy to remain at an elevated temperature. However, the aluminum VersaPlanetary case is sucking a lot of heat from the motors and acting as a heat sink. The VersaPlanetary housing gets hot, but it is nothing to be concerned about.

The bearing speed rating is over 20,000 RPM so this application should not over task the bearings.

In short, the gearbox getting hot is primarily related to the thin aluminum case and is not a concern.

Paul