RCCrawler Forums

hzh007

Hi, Guys.
Previously, I was looking for an available axle with a remote control diff lock. Only RC4WD has one. The size does not match, and it is too expensive for me. So I tried to DIY one.
It is available now. Please find them in my figures.

There are 2 kinds of diff lock in RC:
1. Lock the insider diff gears;
2. Lock the Axle shaft in one side to the Bevel Gear.

I choose the second one. Since the diff house room is very limited.

To achieve this, first I need to made 2 components in the factory.

1. Heave Metal Diff-case
You should buy the diff gear suits from Axial. Or easily, some other gears could be used on Wraith too.









2. Moving Locker Ring
It is thought the shaft. and it could move on the shaft. and it will lock with the diff-case to lock the diff finally.







Some additional tasks:
1. draw a 1~1.5mm hole on the shaft.




2. made a pull stick.







Here is the inside assemble figures:

Before assemble, we should draw in the diff house.


the locked state:


the unlocked state:




with the diff cover:



The next part is how to control it by a servo. I did it like this:













In the last, the hole on the axle should be covered.




It is OK soon. I will upload the video then.

test video is here:
http://s1264.photobucket.com/albums/...t=f0f31542.mp4


If you understand Chinese, you may refer this thread. it is more detail.


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Thank you.

greenjk

Great idea but it looks as though when it's unlocked it will only drive one wheel, is this the case or does it still drive both wheels.

hzh007

Hi, I did not catch you meaning.
But I could promiss it works well. There are 4 diff gears inside the diff-case that i did not post out.
When it unlocked, both wheels could move with different speed.
When it locked, just like the original one.

BikingViking

Hate to say it but if you have 4 spider gears in differential carrier and you are disconnecting/connecting an axle shaft with the locking collar what you are doing is selecting between 2 wheel drive and 4 wheel drive open differential modes (3 wheel drive in a low traction situation assuming a fully locked rear diff) similar to many modern 1:1 front axle setups. with locking collar disengaged you will have no drive power being applied to either front wheel

hzh007

Actually, in my front axle, there is differential all the time.
in the rear, it will be locked and unlocked.
Please notice the pin in the shaft, it will make the shaft sync with locking collar. when it locked, shaft A will lock with the diff-case. the spider gears inside will not move, so the shaft B will sync with A too.

And with lubricating oil, it will not lost too much Torque when it locked. So it always 4WD. not 2, 3, WD.

I have an DIG system, that is another story.

Thanks for reply.

redrokin00XJ

I can tell you right now, that what you installed won't last very long at all. And who would want to take a capable locked up rig and give it a diff? I don't take my rig to Moab and brag about having an open diff, it isn't something I'd want to have in my Wraith or my Jeep. I don't see a very big market for this. Why in the hell would anyone want to take a capable rig like the Wraith and give it a handicap like this. The only reason why you'd want a selectable locker in the first place is to have less stress on the steering ..... my Wraith and every Wraith out there can with stand the very little stress this makes on the steering.

Sorry but I am not a fan of taking a nice strong locker and axle have something that looks very weak put in its place.... All for what?? You're goin to have more disadvantages then advantages...... its just another thing to fix when it breaks. And that is a when and not an if. It will break..... good luck with that.

Tonysmini

I can see your idea behind this and it's a clever bit of engineering, but I don't think you'll need it unless your truck weighs so much that your tyres can't slip when they need to.

Your weak spot will be the pin in your drive shaft, I don't think it will last very long.

Very clever though.

Boostmeister

Regardless of whether it works or not, lasts or not, at least he gave it a go, I am always amazed by people ingenuity on this site.

opek

This is what I see. Looks like it was a lot of fun to build, though!

Tonysmini

It will work as he's described, unlocked the internal diff gears work as normal, allowing the shafts to spin at different speeds, locking it up means the shaft with the lock is pinned, but the other shaft is locked through the actions inside the diff s the gears are held in place by the diff case.

This is what I meant about all of the strain going through the modded shaft pin.

I'm sure with a proper engineering shop this could be made a bit more ressiliant but hats off to you for a great design and installation.

hzh007

Hi, guys.
It could work.
With update the firmware of GT3B, now I have 6 channels to control my Wraith. For this locker, I use the Multi-Position function.
the advantage is this strategy is easy. the advantage is it will waste some power because the friction. But it is tiny.

My diff-case and locking collar are made by Stainless steel. it is really hard and stable. it will work a long time.


I am not a business man. I made this just for my personal style of playing Wraith. Because, 95% of the time, it needs diff. Only 5%, it need to lock the diff.
I want it could steering stably. it needs the diff just like the 1:1 vehicle. The front will always be free. the middle and rear may need locked sometimes.

that is the propose I made it.
Thank you.

hzh007

Thanks for the comment.
My English is poor to give the accurate explanation like you.

johnnyh66

That's great hzh, good job!
I like an open diff. I run open diff in my 2 fast rigs: My FOFF rig and my basher rig.
And I run a locked diff in my 2 slow competition rigs.

You have done a great job!

Tonysmini

You're welcome, your English is better than my, well any other language actually.

I love finding these scale engineering masterpieces, and peoples ingenuity with their designs. Much better to have an idea, build it and try it out than just bolting bits on.

butti

Great work! I think its a great idea. Perfect for a trail rig..in the full scale world most trail trucks are not fully locked up all the time. Often they run selectable or automatic lockers such as ARB or detroit EZ. I bet it turns awesome unlocked. I would love to see you test the turning radius locked vs. unlocked on a high traction surface.

May not be a huge difference as you are running the front open all the time but i bet it is still very noticeable.

BikingViking

Actually I see what you mean, in your pic of the axle shaft it looked like you had rounded off the end of the axle shaft where it fits into the spider gear and were essentially locking the axle shaft to the spider, upon closer inspection I see that it still has the flats and that you are locking the axle to the carrier itself. My bad, guess I should look a bit closer before commenting . And as stated, your english isnt so bad at all, I have people in my own country I have a harder time understanding than yourself

hzh007

Hi, guys.
I made a video here to test the diff locker.

f0f31542.mp4 video by hzh007 - Photobucket

Tonysmini

looking good, now it's time to test it out in the wild

hzh007

Yes, Friday I will be free. Then I will go out and test it.
I hope it could work well.

patrol_maverick

Well done. I admire your ingenuity.

I'd like to see a Lock-Rite type locker. They're so simple, it suprises me that no one has made an R/C Lock-Rite yet. (unless I've just never found one)