REC Gearbox

[RobotExtreme]

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REC Gearbox is a project that has been tested on our Team robots since 2012. After a hundred of fights, tests and fails, here you get the best improvement possible on drill based gearbox !!

Diversity

REC Gearbox can be produced at differents final ratio as 6:1, 24:1 and 36:1, meaning that you can select the one that best fits your project.

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Power

REC Gearbox break the wall of RS550’s motors type, handling also RS775 motors on 24:1 version.

No stall

The most significant improvement on our Gearbox is the replacement of all parallel pins to taper pins, so no loose pin, no instant stall, no smoke!

Robust

REC Gearbox is made from 45x45mm 6061 Aluminium alloy and have 12x M6*1mm threaded holes.

Dual bearing supporting the main shaft, make sure that everything will keep running even under big radial loads.



General dimensions:

Square – 45x45mm

Main Shaft length (12mm) – 38mm

3/8 UNF Theaded shaft length – 15mm

Total length – 145mm (including RS550 motor)

Weight – 473g (including RS550 motor)



Prices:

Plug and Play

6:1 version – 30£ including RS550 motor.

36:1 version – 30£ including RS550 motor.

24:1 version – 34£ including RS550 motor.

Please for more information e-mail – info@robotextreme.pt

[R9000]

I know a lot of people use 3/8 UNF threaded wheels as a result of using drill gearboxes, but I could see just a regular shaft with a flat ground in it or a hole through being more versatile.

[maddox10]

I have streamlined that drillshaft fact into a hex 17 sleeve so we can fit RC wheels onto it without modifying the shaft.

[PanoramicHarry]

Can these gearboxes be sold without the motor? Got some motors going spare and wanna put them into use.

[RobotExtreme]

Hi Harry,

Sure, contact by email please.

[Runsler]

Hi, could you tell me more about the motors used? Ampere and Watt, with given 3s (11,1V) LiPo?

Want to figure out if my esc could handle 4 of those, or if i'd need a second one... or a bigger one... or go 2wd... or drive chains... or whatever. Would also be way easier to calculate the needed battery capacity if it is only used for the drive system. (or do you just happen t have some values from experience for me there?)

[RobotExtreme]

Hi Runsler,

Sorry for the delay on reply.

The motor used is an standard DC motor for ours application with the follow specifications (real/measured), Please consider that all these values is for motor not assembled on gearbox.

No-Load speed @12V - 13200rpm
No-Load speed @14V - 15300rpm
No-Load speed @18V - 19800rpm - Nomimal voltage

No-Load current @12V - 0.67A
No-Load current @14V - 0.74A
No-Load current @18V - 0.92A - Nominal voltage

Stall current @12V - 80A
Stall current @14V - 93A
Stall current @18V - 120A - Nominal voltage


~20 kg radial load on gearbox shaft (consider peak current could be ~4x):

Load current @12V - 5.7A
Load current @14V - 6.6A
Load current @18V - 8.6A - Nominal voltage

Best regards,

Guilherme

[Runsler]

I am not quiet sure if i understand the "radial load" part (i am quiet good at physics, just not in english...), but these really help a lot.

I'm currently trying to build a feather spinner, but since the next event might be before i am ready with that, i'm also considering using parts of that (mainly the esc) for a raptor pusher/wedge/something like that. Something smaller and simpler i can definitly finish in time, and your gearbox/motor-combo seems to be a nice solution for that.

So now i have to think how many motors i could use with my 40amp esc (it would handle both sides, so 2 or 4 motors). It could possibly handle a bit more than that for a short time, but got a fuse for 40amp, so... don't want to risk it.
Seeing those ratings... even if a real "stall" doesn't happen too often, i think just two of them should be enough.
I'm gonna do a bit more thinking and possibly placing an order the next few days... maybe i just order 5, do some testing and and either got 3 or 1 spares o.0

[RobotExtreme]

Hi Runsler,

Radial Load:
radial-axial_load.jpg

Im not sure if a "40A dual channel" ESC can handle 4 Gearbox on a feather, take in consideration that during a fight, all the mentionated (Load current) values are easily exceeded.

Best regards,

Guilherme

[sean retro]

Is there a size different between the 6:1, 24:1 and 36:1 ratio?

[RobotExtreme]

Hi,

At the moment i just have:

6:1 – 3300rpm

24:1 – 825rpm

36:1 – 550rpm

Best Regards

[RobotExtreme]

Hi,

Here is the 2D file for reference.

[JohnandZander10]

Hi Rory, would you have a link to 3/8 ING threaded wheels as I have a couple of these motors but struggling to make them work with any wheels I have,
Many thanks,
John

[RogueTwoRobots]

Hey John, there aren't any off-the-shelf solutions that screw directly onto 3/8" drill shafts anymore. Robo Challenge used to do wheels that had nut inserts in them but they no longer make them. Most solutions are custom, the simplest of which is along the same lines as the Robo Challenge wheels, heating a nut and pushing it into a plastic wheel hub. Takes practice to get right and can often have a bit of wobble.

What size wheels are you after? I've got some Banebots ones with a hex hole through them that fits onto a corresponding brake pipe fitting with a 3/8" UNF thread. They're 98mm (104ish with bike tyre fitted), not sure if that's any use. Made a video a while back talking through that method: https://youtu.be/TLGZ-up22tU

[RobotExtreme]

Hi,

Robot Extreme Competition have now in stock 3 types of motors!!!!

https://www.robotextreme.pt/product-category/motors/

New REC GearBox link!

https://www.robotextreme.pt/product/rec-gearbox/

Check out!!

Guilherme