Connect to Shaft of RS 775 Motor

[amesmich]

What is the best way to connect to the shaft of an RS775 Motor. We can machine a part just not sure how to mechanically attach to it. Any idea, or examples, or products. We want a direct drive 1:1 so a versa planetary is not ideal unless I am missing something. Thanks

[Ether]

Originally Posted by amesmich

What is the best way to connect to the shaft of an RS775 Motor ... We want a direct drive 1:1

May I ask what you are intending to direct drive?

[Jim Wilks]

1:1 is not common as the free speed of these motors is so high.

The most common mechanical connection is a press fit to the motor shaft.

[Ether]

Originally Posted by Jim Wilks

the free speed of these motors is so high.

either 5700 or 13000, depending on which 775 motor he is referring to.

[Cecil]

We used a VersaPlanetary in a 1:1 configuration for Aerial Assist. You can buy a 1:1 base kit and use it as is, just assemble and go. The input gear meshes just fine with the output shaft. You can choose different output shafts too, depending on what your use is.

[amesmich]

Originally Posted by Ether

May I ask what you are intending to direct drive?

Lead Screw


Looking at the 18v did the calcs we will use two of these on 8tpi lead screws. Got the torque and speed figured out even with voltage drop. Now we just need to figure out how to couple the lead screw to the motor. We will can up a coupler once we know how to effectively attach it. Found this online and if you click on the model numbers you get a real cool interactive torque, voltage, rpm, efficiency calculator.

Obviously the free speed will not be th eloaded speed. We plan to load the motor with about 30 - 40 oz/inch of torque.

[Ether]

Originally Posted by amesmich

Found this online

What does the pronoun "this" refer to?

Was there supposed to be a link?

[amesmich]

Originally Posted by Ether

What does the pronoun "this" refer to?

Was there supposed to be a link?

Sorry got sidetracked and forgot the link

http://www.mabuchi-motor.co.jp/cgi-b..._ID=rs_775vcwc

[Lil' Lavery]

Banebots sells 10tooth pinion gears to use with RS775 motors. Other gears with a press fit for a 5mm shaft should also work (or you could bore it yourself).

http://banebots.com/p/S24P-GMC1-50

[droswell]

I might be confused, but it sounds like you're attaching the motor directly to a lead screw?

If this is the case, I would reconsider. Running most lead screws at > 1000 rpm is probably not a good idea. Even fine threaded screws will move extremely rapidly at this speed, if they have enough torque to even turn the screw. This is the perfect case for using a gearbox, such as a VersaPlanetary from VEX or a P60 from Banebots.

[Jared]

Check out this document for some lead screw calculations/guidelines:
http://www.thomsonbsa.com/pdf/bsa_en...og_section.pdf

[Mr V]

For Ultimate Ascent we attached a lead screw to a Versaplanetary with the 1/2" socket from this set (since we had 1/2" output shaft VPs) http://www.harborfreight.com/7-pc-38...set-67929.html because we needed the swivel aspect.

We used a nominal 3/8" lead screw drilled and tapped it to put a bolt through the pin retainer hole and then drilled through the socket and VP output shaft for a cotter pin to retain the socket to the output shaft. We did choose to turn the end of the VP output shaft so that it would extend into the round hole in the socket because we did not feel the shallow depth of that socket didn't have sufficient room for the cotter pin.

If you do not need a swivel head to NAPA and get a single 1/2" impact socket in either 3/8" or 1/2" drive depending on the lead screw you are using.

As others have mentioned you can use a VP as a 1 to 1 but I think you'll find that a little fast. But you can always try it and if it is deemed too fast put a reduction stage in.

[amesmich]

Thanks for all the feedback. It does not fall on deaf ears. The speed is a good point. We are considering a gearbox but needed to plan for any possibility.

Thanks

[FrankJ]

I use the green bearing retainer Loctite with a tite slip fit. Getting the press fit just right & bending the motor shaft is right next to each other.

When you say voltage drop do you mean your adjusting the 18 volt curves for the 12 V available?

[amesmich]

Originally Posted by FrankJ

I use the green bearing retainer Loctite with a tite slip fit. Getting the press fit just right & bending the motor shaft is right next to each other.

When you say voltage drop do you mean your adjusting the 18 volt curves for the 12 V available?

We readjusted for the 12v and then accounted for a non-ideal power source. So voltage drop of battery under load or after some time. Not a big factor for us but not forgotten either.