T&L Publications

Hi.
Does anybody know where I can find a worm gear assembly that is suitable for hobby servos or a hobby servo that does not backtrack (rotate) when the power is removed?

Tamiya sells a motor and gearbox using a worm gear (Item 70103-500). This uses a small Mabuchi type motor and has reduction ratios of 101:1, 269:1, and 719:1. This might work for light loads. These may be available at hobby stores. Sometimes Fry's has them at about $8 to $10.

If you need something heavier, Bodine Electric may still make electric motors with worm gear gearheads. These motors were usually fractional horsepower, quite often in the range of 1/4 horsepower.

Another possibility would be the winches sold for bumper mounting on off-road vehicles. These probably have a motor and worm gear assembly that could be removed.

tolisn wrote:Hi.
Does anybody know where I can find a worm gear assembly that is suitable for hobby servos or a hobby servo that does not backtrack (rotate) when the power is removed?

I just listed a motor with gearbox that uses a worm gear in the gearbox but it would be 2 to 3 times the size of a servo

I think servo is a key word here. I think he wants to have the motor stop at a known or steerable position and then be able to remove power without the servo being able to drift back. You can't find two compatible parts? Can or would you rig the two (worm drive and servo) together or do you want them to come as a unit?

tolisn wrote:Hi.
Does anybody know where I can find a worm gear assembly that is suitable for hobby servos or a hobby servo that does not backtrack (rotate) when the power is removed?

I have tried this on the servo I have. Turn the power off slowly (I have a power supply with large caps, so the voltage drops slowly. When the power that feeds the motor is off then turn off the pulse going to the servo. The servo will stay where it was last. A note here; when you turn off the power the pulse current will go up.

SETEC_Astronomy wrote:I think servo is a key word here. I think he wants to have the motor stop at a known or steerable position and then be able to remove power without the servo being able to drift back. You can't find two compatible parts? Can or would you rig the two (worm drive and servo) together or do you want them to come as a unit?

Thanks for your suggestions.
What I'm after is a worm gear box that can be directly coupled to a standard hobby servo. I don't want the output shaft to rotate when the power is removed from the servo.

tolisn,
Did you ever find a gearbox somewhere? I also need one for a camera platform that has 950g all on one side of the pivot point, so need to gear it so the weight on the servo is not to much but will also hold position when the power in turned off.

Sorry. I never did find such a gearbox for a standard hobby servo. Maybe you can try servocity. They have a lot of pan and tilt systems.

I am thinking of maybe using a worm gear setup from these guys. https://sdp-si.com/eStore/


Not sure if you can get a worm that will fit directly onto the spline of the servo?

tolisn wrote:Hi.
Does anybody know where I can find a worm gear assembly that is suitable for hobby servos or a hobby servo that does not backtrack (rotate) when the power is removed?

If you can't find the gearbox you seek, you might want to have a look at an option form Firgelli:

http://www.firgelli.com

These guys make a wide variety of actuators, some of which use "worm gear" drive technology so they can hold a position once power is removed. Some examples pictures of offerings from their web site:





They area bit pricey, but if you have single need this might be a good place to start so you don't have to cobble together a bunch of parts. Hope this helps.



Vern