RWD reduction box

[Domt177]

After an overly long email chain I have some info in the ZeroEV gearboxes and Zonic motors. Let me know if you are interested and I'll share.

Certainly interested in finding out more

[stuartd]

Excellent work

I’ve just got the material for making my spine shaft I’ll post pictures when it’s done

[SciroccoEV]

Now I'm at a stage with the Lotus Excel chassis rebuild that I can do a dry fit, I can see that the shaft offset with just the Leaf gears is going to be a problem. There's very little radial clearance for the propshaft at the front of the chassis, so it would mean having to move the motor up or down. It can't go down, or it would hang below the chassis by the full offset and there's not much room to go up either, not to mention, I don't really want to move 60kg of motor up nearly 80mm. What I ideally need is a second pair of gears to get the output shaft roughly concentric with the input. That's more engineering that I want to take on right now, so in the interests of actually moving my project on, it's looking likely that I'll be getting one of the Zero-EV reduction boxes.

They're only rated at 260Nm, which is less than the EM61's 280Nm, but adequate for the EM57's 256Nm (both with stock 80kW inverter).

I have a contact who can perform shot peening, or cryogenic treatment, which would increase the torque handling capability, but I'm actually happy to limit the torque and just push the constant torque area higher up the rev range. Ultimately, the only place that torque matters is where rubber meets the road.

[cajunfj40]

If y'all want to check out some other options for RWD reduction boxes, perhaps steal a page from the 4x4/rock crawler world and look at transfer case reduction boxes. These are typically 1.99 to 2.73:1 gearboxes, available in either spur gear or planetary gear setups. The one I've looked at most is the older '79 to '85 Toyota gear-driven transfercase setup - stock low range is 2.28:1. At some point I had looked up the bearings and found that there were high-speed variants available that fit those dimensions, but I didn't write down anything other than that it was possible. The gist of the idea is that you would unbolt the reduction box from the "drop box" that houses the gears (or chain) that goes down to the front output that would drive the front axle, make an adapter plate and coupler, and run the rear driveshaft out directly. You can leave the shifters in to have a 2-speed setup, or just leave it in low. There are also so-called "doubler adapters" available that comprise an adapter plate for the rear of the reduction box and a splined coupler that fits the output shaft and would then fit the input shaft of the next gearbox bolted inline. The second gearbox in a doubler setup sees full engine torque multiplied by 1st gear and then by the first box's reduction gear, so they're pretty stout. If you need lower gears, there are various aftermarket lower gear ratio setups that fit the stock cases.

For a cheaper option, you can just saw off the part of the transfer case housing that goes down to the front driveshaft output (the "drop box"), toss out the parts that are in it, and block off the hole in the case. That gives you a driveshaft connection out the back, leaving you needing to make an adapter for the front that "looks like" the rear end of the transmission the transfer case originally mounted behind. Advance Adapters and lots of other companies make all sorts of couplers and adapter plates to match Transmission A to Transfer Case B, etc. I do not know how well the sleeve bearings in the planetary types will hold up to high RPM, though.

For a full roll-your-own setup, Quick Change gears are readily available. You'd use two sets and a countershaft, much like how the low-range gears in a gear-driven Toyota transfer-case are arranged, though those also have a splined coupler for direct drive. With two sets of Quick Change gears, you get a *lot* of fine-tuning available on your gear ratio.

Good luck, and have fun!

[SciroccoEV]

Torque Trends in the US sell reduction gearboxed for offroad use. They also sell units for EV use.

Talking to Chris Hazel of Zero EV, Their first reduction gearbox was similar, using one of the same core epicyclic reduction gears that Torque Trends buys in. It turned out to be too noisy and generate too much heat. Noise is going to be a problem with many gear sets not optimised for quiet running.

Anyway, after a bit of back and forth with Chris (because their gearbox is only officially rated for 260Nm), I have one on order and should get it in a few weeks. I have a contact, who may be able to shot peen or cryo-treat the gears to increase fatige strength and torque capacity, but the plan is to limit the input torque, but extend the constant torque area up the rev range. Looking at data online, the EM57 can generate 260Nm up to around 6500 rpm.

[Tremelune]

What's that run? I was only aware of the Torque Box, which weighs in at USD$4,000.

[SciroccoEV]

My friendly local UPS driver brought me a box from Zero-EV today. This was inside.

[tom91]

Mind disclosing how much it cost? They provide any specifications with it to allow you to make couplers for it and adapter plates?

[Tremelune]

Yeah, what is this thing? Pre-production? What's the mating face and output? It's not something one can go to their site, click and buy...

[Alibro]

Very nice.

Sometimes you have to spoil yourself.

[SciroccoEV]

Chris asked me not to share the CAD file or cost right now. They're still changing the design and exchange rates keep fluctuating.

However, if you were to buy the version designed to bolt up to a Hyper 9, you should be looking at less than £2000 all in. They're expecting to soon have a version with an integral Hyper 9 mounting face that would be a bit cheaper and will have versions designed to mate up with their new Zonic motor lineup.

The imput spline on mine is a DIN 5480 N25x1.25x30x18x9H

[remy_martian]

Hyper9

Talk him into doing a Leaf hookup...

[SciroccoEV]

Talk him into doing a Leaf hookup...

I had enough trouble persuading Chris into selling me one to use with the Leaf motor at all, becuase of the torque the Leaf motor can produce.

The gearbox is only officically rated to 260Nm, which is fine for the 256Nm of an EM57 on the OEM 80kW inverter, but an EM61 would be 280Nm. It's only becuase I convinced him that even if I push the power to 160kW+, I'll be limiting PEAK torque to 260Nm, that he agreed to sell me one for my application. That's effectively what Zero-EV will be doing when it's paired to their 180kW Zonic motor.

[remy_martian]

Meh. Just rate your tires to break traction at 260*xNm where x is the final drive ratio and you'll likely be fine with even a 180kW inverter. That total traction break includes an LSD, of course, if installed.

In other words, in the absence of a designed-in fuse, the gearbox becomes one. Fuses are prevalent in aerospace design to keep upstream pieces from getting beefy/heavy.

[Bratitude]

Hyper9

Talk him into doing a Leaf hookup...

if they have a hyper 9 face, ala neam B-face then my leaf adapter plate is all that is needed

[Domt177]

Just watching this video, at 17:13, they appear to use a reduction gearbox with the 360nm zonic 180 motor.

Looks like the same one as the 260nm rated box (could be wrong) so looks like it’s capable of more unless they’re limiting it.

[SciroccoEV]

Looks like the same one as the 260nm rated box (could be wrong) so looks like it’s capable of more unless they’re limiting it.

Yes, same gearbox from Zero-EV. They're limiting peak imput torque, but still getting to 180KW.

When it comes down to it, the only place torque matters is where rubber meets the road and that's down to the overall gearing.

[rstevens81]

Tbh, there aren't many normal gearboxes that are strong for 360Nm from an electric motor (the zf530d being suitable oversized to be an exception) we all probably should be torque limiting till 5000 rpm when using a normal gearbox let alone the zero reduction gearbox.

Obviously this my opinion and there are thouse who have more direct experience knowing what gear gearbox is good for what.

[Romale]

one day I sold two motors to a customer, a sheet with redesigned controllers. he wanted to make them both rotate the gimbal for a rear-wheel drive car. he made a prototype of an excellent 4:1 step-down box combining two motors. but then Covid took him away and this case remained unfinished.

Someday I will do a similar development to put 4 motors in my hummer H2.
I want two motors to rotate the rear axle and two motors to rotate the front axle.

[Bratitude]

some late-night shenanigan's...

gen 1 intermediate shaft/gear just dropped right into a gen2 box. from first glance, the shafts are the same! just the removable gear is a different pitch!

so you can swap gen1/gen2 ratios.

the rings gears are the same, gen2 is about 5mm thicker...

(gen2 removable gear sitting on top)

[Tremelune]

What does that buy you? Aren't the ratios between Leaf years very, very similar (pretty much just 8:1)?

[Bratitude]

What does that buy you? Aren't the ratios between Leaf years very, very similar (pretty much just 8:1)?

well being that the em61 have larger magnets and higher torque output, and the em57 gearbox has bigger gears... and slightly more reduction...a race car drive train!

[LeonMN]

good day!

Is there any news on this issue?
I would like to get some kind of ready-made worm that can be put into production so that the necessary gears can be machined at the factory. Well, or as an option, ready-made gears can be?

in general, I would very much like to have a maximum speed of more than 147 km / h

[JustinBenson]

This RWD leaf gearbox mod looks perfect for me. How has it run in the real world? Many miles? Can I buy this from you/ your supplier? Rather than re-invent the wheel of course.
Amazing taxi projects BTW.

[janosch]

This RWD leaf gearbox mod looks perfect for me. How has it run in the real world? Many miles? Can I buy this from you/ your supplier? Rather than re-invent the wheel of course.
Amazing taxi projects BTW.

Taxis ran 20k+ miles, no problems with it. I sent you a PM. Need to figure out shipping to where you are & find out the price for you.