Special 3+R Gearbox driving ring layout

[lipcsey]

Hi,

Do you guys know of any existing 3+R designs that feature a different driving ring setup where you'd need both driving rings be engaged for a gear to be selected?

Normally you only engage one (otherwise gears would mesh against each other), but I'm looking for a design where you deliberately engage 2 at a time.

In here you see both rings flicked up,

i.e:

- this could give you 1st.

- Left down right up could get you 2nd

- both down would be 3rd-

- left up right down Reverse

In fact I'm not exactly convinced such design is possible at all, but haven't had the time to thoroughly inspect up close.

Cheers!

[Lemon]

I've just come up with this, so I'm not 100% sure if this works: Try 4 http://brickset.com/parts/654227 having different speeds, with a driving ring in between 2 of them (like in your picture). Now connect the two driving ring axles to a differential and connect a differential to the drivetrain of the vehicle. A differential is used as it avarages the rpm of the 2 16T gears selected by the driving ring. Connecting none or only one should be neutral. For example, if the four 16T gears have speeds of -3:1, 1:1, 1:1 and 7:1, the output will be -1:1, 1:1, 2:1 or 4:1. Not ideal, but its a starting point.

I can make a drawing if you dont understand the description.

Alternatively, you could try to link two transmissions together in series. If the first one has 1:1 and 1:1,5 and the second 1:1 and 1:3 you'll have 4 speeds: 1:1, 1:1.5, 1:3, 1:4.5 and 1:6. You'll have to select one of each at the same time, but without a reverse (or two reverses).

Edited September 22, 2014 by Lemon

[piterx]

i made this one wich is linear and can handle all the torque you want if you brace it well :)

[lipcsey]

i made this one wich is linear and can handle all the torque you want if you brace it well :)

Driving rings go on top or?

@Lemon: I'll give the differential idea a go and see how it turns out. I think I got the idea, I'll get back if there's anything.

Thanks.

[piterx]

no there are no driving rings... it's just a linear gearbox....you can invent something out of it tho

[Jurgen Krooshoop]

This is not 3+R but 4 speed, but both driving rings must be engaged.

[lipcsey]

This is not 3+R but 4 speed, but both driving rings must be engaged.

Nice design, thanks!

Quite robust and massive but I'll need that torque anyway. The idea is to have 2RC modules on board, so a total of 4 RC buggy motors coupled, to propel my vehicle. I'm not anywhere close, still doing some trial and error, researching etc.

In the beginning I wanted the gearbox to be shift-able using only 1 motor, so the auxiliary output of the rc module would have done the gear changes for me, but turns out there is no such design that's reliable as it also has to withstand a great deal of torque (coming from 4 RC motors). On the other hand I can't precisely set the driving ring to middle idle state with any motor (not even with mindstorms' servo) as the positioning is not accurate. Since I'm going for max speed, any slack gear change would result in cracking gears and the whole drive-train falling apart, so I need to get it right.

So right now I'm planning to have the mindstoms brain on board attached to it 2 sensors to detect shift requests, and 3 servo outputs, 2 of which will do the shifting itself, and one other for the AWD/RWD lock (possibly used as a launch control feature too). Should be no issue as it's easy to program, provided that it will know by itself which gear is engaged. On top of all this I got to have the 2 RC modules + 4 engines built into the structure.

I've done tons of tests on coupling the rc buggy motors, and turns out there is no point of not hard coupling them in my setup, they proved to be accurate enough, so going to be hard coupled.

As the output of the 'engine' will be hooked up to a 2 way clutch, flicking up will transmit the power to the gearbox and the wheels, flicking down will activate the break system on a different axle (leaving the vehicle go by its inertia) at the same time. Only thing's missing is the reverse, that's why I was looking for a 3+r rather than 4speed, BUT your design is more than helpful, I'll find a way to build it in to fit my needs. Thanks again!