Combining Motors

[CharlesD]

Hi,

 

I could not find anything definitive on this, so i am asking it here.

What would you think is the best way to combine motor output, i have always been doing it like this;

 

But from what i see others do you can also combine them like this;

 

Is it a matter of prefference, or are there donwnsides to the solution above?

[brunojj1]

The more gears involved, the higher the friction. I´d suggest the following solution which works quite well:

[Jurss]

Main issue is that there is so much torque on that one central axle with those 3 motors.

[CharlesD]

5 minutes ago, brunojj1 said:

The more gears involved, the higher the friction. I´d suggest the following solution which works quite well:

 

Would you take the power from an extra gear connected to the red gear?

How would you combine three motors?

[brunojj1]

14 minutes ago, CharlesD said:

Would you take the power from an extra gear connected to the red gear?

How would you combine three motors?

I´m not sure I understand your issue correctly. The indefinite number of motors are supposed to be connected and equalize the small differences either way & distributing the resistance.

Output torque combined onto 1 axle no matter which one. In general you want to reduce the number of gears to the minimum to eliminate friction and use all the power.

EDIT: on your first picture you have a gear rediction of 5/3 and on the second it´s plain 1:1, so that is the main difference there and as far as I understood that was not the question.

Edited January 31, 2022 by brunojj1

[CharlesD]

I see, i was thinking about it the wrong way.

Power takeoff can be off any axle or gear?

Thanks for the response.

[allanp]

It would be better to take power from the middle as you will be loading the output shaft equally on each side, which should lessen side loading of the axle reducing friction. And also like others have said use fewer gears and axles if possible. 

[CharlesD]

Thanks for the help!

[Brickthus]

For powering helicopter rotor experiments I have been using 4 L-motors geared-up.

I arranged 2 layers of gears axially on a central axle, one layer having 40-tooth cogs on the left and right motors driving an 8-tooth cog on the central axle and the other layer having similar from the front and rear motors.

Admittedly this has central axle torque of at most 80% of the torque of one motor.

Mark

[Zerobricks]

One tip. The bigger the gears you use, the more efficient your driveline, due to the lower side forces created on the axles. That is why drivelines with for example only 8 tooth gears are so rough and inefficient.

[1gor]

54 minutes ago, Zerobricks said:

One tip. The bigger the gears you use, the more efficient your driveline, due to the lower side forces created on the axles. That is why drivelines with for example only 8 tooth gears are so rough and inefficient.

Since you have lot of experience in that area Jerry, what do you suggest with 2 XL motors (PF motors) and planetary wheels from 42099 set. (Pulling power needed)

Thanks

[Zerobricks]

3 hours ago, 1gor said:

Since you have lot of experience in that area Jerry, what do you suggest with 2 XL motors (PF motors) and planetary wheels from 42099 set. (Pulling power needed)

Thanks

Send me a private message so we don't derail the topic.

[CharlesD]

Please derail, i consider this more of the same interesting stuff.

[1gor]

8 hours ago, CharlesD said:

Please derail, i consider this more of the same interesting stuff.

Charlie, my post is about hard coupling 2 XL motors (I wanted to have strong pulling power for my tractor), my question was should I use 24 gears only for hard coupling 2 XL motors. I use differentials from 42109 set and hub reduction from 42099 set. I got my answer from @Zerobricks, but with his permission only I could post here what he suggested.

Kind regards

[amorti]

@1gor you'll haven a very slow vehicle if you use only 24t gears to connect PF XL motors 1:1, then downgear at 12:28 on the differential and 1:5.4 at the planetary hub. Like REALLY slow.

I'd suggest building a very quick and dirty test rig, just to see how slow we're talking about. Probably you'll want to gain at least a little speed before you get to the diff.

[1gor]

2 hours ago, amorti said:

@1gor you'll haven a very slow vehicle if you use only 24t gears to connect PF XL motors 1:1, then downgear at 12:28 on the differential and 1:5.4 at the planetary hub. Like REALLY slow.

I'd suggest building a very quick and dirty test rig, just to see how slow we're talking about. Probably you'll want to gain at least a little speed before you get to the diff.

My personal goal is to use XL motors without typical oscillation in power output

4 hours ago, amorti said:

@1gor you'll haven a very slow vehicle if you use only 24t gears to connect PF XL motors 1:1, then downgear at 12:28 on the differential and 1:5.4 at the planetary hub. Like REALLY slow.

I'd suggest building a very quick and dirty test rig, just to see how slow we're talking about. Probably you'll want to gain at least a little speed before you get to the diff.

Like upgear with 36 to 28 tooth?

It should use Xerion tires

[1gor]

On 2/5/2022 at 9:27 AM, amorti said:

@1gor you'll haven a very slow vehicle if you use only 24t gears to connect PF XL motors 1:1, then downgear at 12:28 on the differential and 1:5.4 at the planetary hub. Like REALLY slow.

I'd suggest building a very quick and dirty test rig, just to see how slow we're talking about. Probably you'll want to gain at least a little speed before you get to the diff.

Yes, even when I use 36-28 from XL motors and 12-28 on differentials it is veeeeery slow, so next I'll try with 36-12 from XL motors because I want it to be (still) Fastrac

Thank you

Edited February 9, 2022 by 1gor

[gyenesvi]

@1gor have you tried the regular diff that works with 20:28 gearing? That should give it a bit more speed than your current setup, and I don't think it would be a weak spot, because of the massive down-gearing in the planetary hub, the diff still runs with relatively low stress. I think using the heavy-duty diff and the planetary together is an overshoot in most cases.

Edited February 8, 2022 by gyenesvi

[Zerobricks]

Just now, gyenesvi said:

@1gor have you tried the regular diff that works with 20:28 gearing? That should give it a bit more speed than your current setup, and I don't think it would be a weak spot, because of the massive down-gearing in the planetary hub, the diff gets relatively low torque. I think using the heavy-duty diff and the planetary together is an overshoot in most cases.

Good call, agreed.

[1gor]

6 hours ago, gyenesvi said:

@1gor have you tried the regular diff that works with 20:28 gearing? That should give it a bit more speed than your current setup, and I don't think it would be a weak spot, because of the massive down-gearing in the planetary hub, the diff still runs with relatively low stress. I think using the heavy-duty diff and the planetary together is an overshoot in most cases.

Thanks buddy, that was one of solutions I had in mind but was worried about stress on older differentials.

Thanks @Zerobricks 

[1gor]

19 hours ago, gyenesvi said:

@1gor have you tried the regular diff that works with 20:28 gearing? That should give it a bit more speed than your current setup, and I don't think it would be a weak spot, because of the massive down-gearing in the planetary hub, the diff still runs with relatively low stress. I think using the heavy-duty diff and the planetary together is an overshoot in most cases.

Today I have tried this solution and it us indeed faster and power output is continuous what is great when using XL motors. Eventually I will try tomorrow with higher upgearing and heavy duty differentials to gain overall reduction like with PF L motors on last version. (I keep in mind that L motors rotate some 315 rounds per minute and XL 220 rounds per minute, so tractor would be slower anyway than last version)