EDIT:

Changed the topic to fit the discussion better.

Edited September 7, 20177 yr by Mechbuilds

For independent tracks driven by one motor you need a something to pass through turntable. Most of the time older type of differential is used, see pictures from my rope front shovel excavator where I powered 6 functions from 1 motor, including independent track movement:

20170515_182156 by Ivan Moc, on Flickr

the shaft in the middle is drive for right side, you have to place old differential on it that will drive the 16z gear on left for left track. Then you have to use top 24z gear on differential to move left track and shaft that goes in the middle for right track. I hope it is clear.

Nice Idea! I To make a track mechanism you just need to make "gearbox" in wich you will can select function:
1: left track
2: right track
3: both tracks
4: turning using both track (one goes in second direction)
And change direction with batterybox switch, or use one pf switch.

Good Luck!

P.S. Those "hydraulics are "linear actuators"

Hmm.. I'm thinking about putting the motor in the tracks center and the switch so it works like this:

Motor spins the tracks forwards and backwards using the battery box direction switch. So when you put the battery on, it will go forwards immediately. 
To stop the vehicle from moving, put the battery in middle position. Very easy and simple to do. 

Okay. Then i'm going to make a gear selector system that disables the left or right track so it'll only spin the other. That way i can make it turn. 
But then again, there is an even simpler solution. Make a switch that'll lock both wheels to turn the same direction so i'll have forward and back. Then make the second gear reverse the wheels so it'll turn. 
So i'll have left position for power and right position for steering. And battery box switch will determine which direction it'll go or turn. 

Very very simplified and working solution to this problem. 
Time to figure out the gearing. 

I'd throw in a subtractor so the excavator can turn more smoothly.

23 minutes ago, suffocation said:

I'd throw in a subtractor so the excavator can turn more smoothly.

Yea, but he got only one motor.

 

It can be done with just one motor. Not the most efficient solution but technically interesting.

Edited August 30, 20177 yr by suffocation

3 minutes ago, suffocation said:

It can be done with just one motor.

Yes, but he will need a function selector.

Yeah, that's kind of the whole point.

1 hour ago, Mechbuilds said:

Hmm.. I'm thinking about putting the motor in the tracks center and the switch so it works like this:

Motor spins the tracks forwards and backwards using the battery box direction switch. So when you put the battery on, it will go forwards immediately. 
To stop the vehicle from moving, put the battery in middle position. Very easy and simple to do. 

Okay. Then i'm going to make a gear selector system that disables the left or right track so it'll only spin the other. That way i can make it turn. 
But then again, there is an even simpler solution. Make a switch that'll lock both wheels to turn the same direction so i'll have forward and back. Then make the second gear reverse the wheels so it'll turn. 
So i'll have left position for power and right position for steering. And battery box switch will determine which direction it'll go or turn. 

Very very simplified and working solution to this problem. 
Time to figure out the gearing. 

It depends on how many functions you would like to control with one motor and on space available. Base with tracks is usually too small to fit motor, battery box and gearing. If you put BB on superstructure you will limit rotation movement due to cable. And if you want to power linear accurators with the motor you will have to pass axles through turntable anyway. The other reason BB and motor(s) are placed into superstructure is weight balance, BB serves as counterweight balancing superstructure and limitng stress on turntable.

This will be an interesting project because i don't have those differential gear things.. I only have the parts that the BWE came with.. I'll just have to figure out a way to gear the thing with those parts.. I'm thinking about having the upper part of the whole thing completely mechanical. So the whole top part will be moved by levers and twistable gears.. But the bottom half will be controlled via one motor.. 

Other solution is to wait till i can order new parts and get the right parts that i need.. But then i'd just go with twin motors.

So i guess this is just a fun little brain teaser project to get to know building with technic.. 

Before the BWE i was only a CCBS figure builder and now i'm stepping to a whole new scene with this technic bit.. I like a good hard challenge. 

You can also use red 16z free spinning gears and driving ring without the white connector to get through turntable.

I'm currently in progress of disassembling the BWE and trying to put all the parts in labelled containers.. It's a big big job but it'll pay out later.. 
I'll probably order up differentials and a large motor + other misc parts like gears and stuff and do it right the first time. 


I have two of these filled up:

Edited August 31, 20177 yr by Mechbuilds

On 8/30/2017 at 4:08 PM, Ivan_M said:

You can also use red 16z free spinning gears and driving ring without the white connector to get through turntable.

 

And set 42055 has them in numbers...

42055 is the best starting kit for this technic hobby. 

Alright, i ordered 5 differentials and some other bits and pieces.. 
I have a new plan for this excavator.. It will have a V8 engine on the top half and the motor + battery will also be on the top half.. All the gearing will go down to the tracks in order to move them.. 

The big flaw in this plan is that i can't have two axles going down the middle so the tracks will only have forward and backward movement so it won't turn.. Unless i can make one shaft have two functions with a switch. 
Is it possible to make it so the engine spins when the motor is spinning in idle. And when i move a switch to the left, it'll move forwards and if i move a switch to the right, it'll turn left.. Then if i reverse rotation from the battery switch, i can make the left switch move the tracks backward and the right switch turn to the right?

I think it could be done with these:



EDIT:

Here are my plans:

Edited September 2, 20177 yr by Mechbuilds

1 hour ago, Mechbuilds said:

The big flaw in this plan is that i can't have two axles going down the middle so the tracks will only have forward and backward movement so it won't turn.. Unless i can make one shaft have two functions with a switch. 

Check 8043 instructions...

41 minutes ago, M_longer said:

Check 8043 instructions...

The best system for a functional tracks no doubt.

Should i just skip the nonsense and order a XL motor to the begin with? 

The excavator i'm building is going to be very large. Not 42055 large but close. 
The original plan is to have an electric track setup and fully mechanical arm on the top half. 
 

Update:








Here are the tracks and center part..

I had to tear apart the transmission and restart.. But currently i have the center turntable and one drive axle coming trough it. 
Now i need to convert the one drive axle into two axles. One for forward and reverse and the other for turning. 
I'm using the basic subtractor scheme. But i'm stuck at how do i turn that one axle into two with a switch in between. 
That switch in image two was just a mockup to test it.

The differentials and gears are coming in the mail shortly. So i'm currently mocking up a test gearbox and leaving space for the differentials. 
The tracks are a slight twist from the BWE track system. But it fits this excavator mock.. 

Any ideas or suggestions what kind of gearbox should i build here? 

You need a configuration that looks something like this (I think it's one of Sariel's builds):

 

But how does that thing turn? I want it to be able to turn 360 degrees so i'm moving the motor and BB to the top half. 

It does turn 360°. Both the red and the green function pass through the turntable coaxially.

16 minutes ago, Mechbuilds said:

But how does that thing turn? I want it to be able to turn 360 degrees so i'm moving the motor and BB to the top half. 

As I said earlier: 8043 instructionsss.

36 minutes ago, M_longer said:

As I said earlier: 8043 instructionsss.

This ^^^

You'll want a sturdier undercarraige than 8043's, though.

 

As for the gearbox, how many functions would you like to implement and using how many motors?