WillChair 2 Build

[rustyjames]

Looking good, Will.

I hear you with the mig, same thing happens to me with the sparks. I guess a full leather tent over your body/chair might work, but those sparks seem to find every nook and cranny

[Burgerman]

Do it out in the rain during a thunderstorm. Best at night. Nobody will think you are mad.

[HotColors]

Nice, another unique design. Nice machine work also. I have some ideas on doing front suspension. I have a CAD file for a truck arm style rear suspension that uses 1/4 midget shocks. Next one i build will have full suspention.

[Williamclark77]

Lol Rusty. The more I try to cover up with the more I catch it on the joystick. I normally just put a cookie sheet pan thing in my lap. The nutsaver. It earned its name after an unfortunate incident welding thin aluminum (it dripped, you can guess to where) and nothing to protect myself but jeans.

Do it out in the rain during a thunderstorm. Best at night. Nobody will think you are mad.

I don't know your exact chances of being struck by lightning, but my dad has been hit twice. Why couldn't my family have those odd with lottery tickets?

Nice, another unique design. Nice machine work also. I have some ideas on doing front suspension. I have a CAD file for a truck arm style rear suspension that uses 1/4 midget shocks. Next one i build will have full suspention.

This is my second one to build. The first is here http://www.willsjunk.com/WillChair

I drew up a CAD model to do four wheel suspension on the one I'm building now. I backed out of it due to the terrain I frequent. Just the front makes it lean enough. I was afraid adding rear would make it too unstable for me. I'm a quad. I don't have the best trunk control. I may eventually do one. I look forward to what you come up with.

Motors and all mounted. Seat pan perimeter lightly tacked together and on as well as the tilt hinges. Everything came out pretty much dead on. Seat height is 17" tall. She's coming together nicely.



Sexy arse on her



Note the belt to motor clearance (or lack thereof). They clear by about 1/16". I still have to get a tensioner in there too!



The wheelbase is as short and narrow as possible



Hopefully this week or weekend I'll finish the seat. There's quite a few parts. It will have power tilt, power leg extension, and manual recline adjustment.

[shirley_hkg]

Any idea how complicated or feasible to make a traditional gear box for this brushless motor to run @16mph ?

Have been longing for cloning BM3 with a Quickie 646 frame .

[hobie1dog]

[Burgerman]

Any idea how complicated or feasible to make a traditional gear box for this brushless motor

Not really sure what this means?

[shirley_hkg]

We need to lower the gear ratio of the existing gear box by half , in order to double the output revolution .

You have to make one or modify one , right ?

Will it survive with the increased stress ?

[Burgerman]

What existing gearbox?

[shirley_hkg]

For example , that came with a Quickie 646 SE @8mph .

[Burgerman]

Not strong enough, and the taller you make the ratios the less efficient it becomes. It magnifies the losses.

[Williamclark77]

Making gearboxes is above my equipment grade.

You can get inline and right angle gearboxes for these motors in nearly any ratio. I do not think these would do great at very low speed geared that high. That brushless "cogging" gets noticeable. I had the first chair geared for that fast. It was a bit "jumpy" at very low speeds. Tolerable though if you just really wanted it and didn't mind dealing with it. Motors and electronics also got pretty hot towing stuff.

Or get out your wallet and have some high pole count motors built!

[Williamclark77]

A two speed gearbox would be the best option. Wish I had the time, equipment, and money to develop one.

[shirley_hkg]

What speed is intended for WillChair 2 ?

[Williamclark77]

Mathematically 10.2 mph. Should do a little more since every motor I've had spun a few hundred RPM faster than the rated speed.

It needs the low speed torque more than high speed mph for the way I'll use it.

[Williamclark77]

I've done a good bit more. No pics since it's mostly apart.

I've had a few ask me about belt tensioners. The motors are fixed and have to be. So, I designed this little feller. Works fantastic. Pain in the butt to make though. I didn't take pictures before test fitting. I will when it comes back off.



I removed the outer flange from the drive pulley to ease belt installation. Unneeded since the tensioner wheel and driven pulley both have guide flanges.

The left side needed to be offset for clearance since the motor is closer. Here's the adjusting block with the tensioner axle's bolt hole offset.



It's machined down round to fit inside the tensioner wheel firmly against the bearing race for extra support. These will be under a lot of pressure. So, I did it this way instead of using a spacer. I'm still amazed every time I have find an offset center how accurately it can be done with three simple tools: A four jaw chuck, a dial indicator, and a little knowledge to get .001" accuracy.

I made the basic rectangle shape this same way, then put it in the mill to accurately locate, drill, and tap the holes. Finally, I put a bolt in it to indicate off of to find the center of the threads. Not perfect since bolts are not perfectly parallel with their threads, but still more accurate than something you'd buy.

Short 20 second video to show it

http://www.willsjunk.com/Willchair2/n-ndvgz7/i-VbmCKXH/A

[Burgerman]

I might have made it in stainless. Or alloy. How are you going to stop it corroding? Grease might work.

[flagman1776]

Will, I love the drive & your workmanship is impecable.

[Williamclark77]

I might have made it in stainless. Or alloy. How are you going to stop it corroding? Grease might work.

The first one I made for the right side is aluminum. After staring at it a bit and seeing how much pressure it will be under when I reverse I decided to make this one from steel. Good Sa516 Gr70 scrap from the work trash can. We'll see if the aluminum one breaks. I'll try my best to!

They will be painted. About .006" of clearance for it to slide. Plenty enough room for a spritz with some black primer from the rattle can.

I had no stainless that thick for it. Not too sure I would want to run a tap through an inch of it either.

Will, I love the drive & your workmanship is impecable.

Thanks! I'm not in a rush. So, might as well do it right.

[popschief]

Has anyone considered one of thesehttps://youtu.be/O4h-Me5lSOY belt drives?

bp

[Burgerman]

No. Because
a) V belts are inefficient and slip.
b) They achieve exactly the same gear ratio changes that using a high battery voltage and a pulse width controller does. The controller IS a gearbox.

Think about it like this.
Use a 1 mph motor. Tons of torque right? Low current. Low speed. Pull a truck...
Use a taller geared 10mph motor, now has 1/10th of the torque. And now takes 10x as many amps at 1mph...

Or

Use a 1MPH motor, so same good torque, low current. But now add 10x the volts. Its STILL got the same torque limited by the controllers max Amps. Still same low current. (and 10x LOWER battery current at 1mph). But it can now also go 10 mph if you wish at max speed because of the higher voltage. Its why will uses 48, I use 43.

[Williamclark77]

Has anyone considered one of thesehttps://youtu.be/O4h-Me5lSOY belt drives?<br abp="715"><br abp="716">bp

For my application they (not necessarily infinitely variable V belts but any mechanical gear change) would be fantastic for the things I use my chairs for. When time allows I do plan on working on it. I certainly could use a low/high range.

V belts like those would be the simplest solution but aren't necessarily the optimum choice due to reasons BM pointed out. That's not to say a VERY similar design wouldn't work. Huge ATVs use them. I honestly haven't had the time to really look into it. Thanks for posting that link.

[popschief]

I once worked overhauling Blackwelder tomato harvesters as a winter job. The system they employed to control ground speed was a large variable speed belt drive. In this way the engine rpm was kept constant to adequately power sorting belts, shaker arms and a lifting conveyor belt. The machine weighed approx. 30 tons before the 11 man crew climbed aboard. There were many maintenance issues but the variable ground speed drive was not one of them.

bp

[Williamclark77]

I once worked overhauling Blackwelder tomato harvesters as a winter job. The system they employed to control ground speed was a large variable speed belt drive. In this way the engine rpm was kept constant to adequately power sorting belts, shaker arms and a lifting conveyor belt. The machine weighed approx. 30 tons before the 11 man crew climbed aboard. There were many maintenance issues but the variable ground speed drive was not one of them.<br abp="674"><br abp="675">bp

That basic design is used on large ATVs, golf carts, mowers, small cars, etc. I wanted to do a high/low range on this chair but simply didn't have time to try to develop one. When time allows (hahaha) I plan on looking into a similar solution. That could have a lot of positive affects, especially on brushless motors where low RPM movement is the issue, or my case where I do grunt work with it. If they can work on those heavier and more powerful applications I'm sure something could be adapted for a powerchair.

Efficiency loss wouldn't make a big enough difference to matter. My concerns would mostly be belt slippage when wet and dirty. Tensioning would be a pita to figure out also. It was on this one

[Burgerman]

You do realise that you get exactly the same affect by choosing the same low speed. But instead of using the hi speed, just use twice the volts? No gearbox needed. Your pulse-width controller and the higher volts becomes the gearbox. The same speed and torque as having 2 speeds. Without needing to actually have 2 speeds... Only with BETTER efficiency.

In your case will, use half the teeth on the motor or double the teeth on the wheel. Or whatever gives this ratio as a set. That doubles your torque. And halves the Amps needed to drive. At 96 volts instead of your 48, you still have the same speed as before. And more range... Exactly the same result as a gearbox, but none needed.

[Williamclark77]

You do realise that you get exactly the same affect by choosing the same low speed. But instead of using the hi speed, just use twice the volts? No gearbox needed. Your pulse-width controller and the higher volts becomes the gearbox. The same speed and torque as having 2 speeds. Without needing to actually have 2 speeds... Only with BETTER efficiency.

In your case will, use half the teeth on the motor or double the teeth on the wheel. Or whatever gives this ratio as a set. That doubles your torque. And halves the Amps needed to drive. At 96 volts instead of your 48, you still have the same speed as before. And more range... Exactly the same result as a gearbox, but none needed.

Practicality would go out the window.

The Roboteq will release magic smoke if fed 96v. Same with the motors. The battery will get quite a bit unmanageable. No room for a 30S pack of any valuable capacity. Not to mention charging difficulties.

As is, mine is in the middle ground speed vs torque wise. A little more speed would be better, but electronics get hot and strained when I add 400 more static pounds to their load (the dynamic load is even higher). Geared any lower and too much speed is sacrificed.

Keeping it at 48v with a mechanical gear change would be much better and far more practical than adding volts.

Nothing that will be happening any time soon either way. Another discussion for another day.

[Burgerman]

Fair enough but a few things you missed.

The battery will get quite a bit unmanageable. No room for a 30S pack of any valuable capacity.

Battery physical SIZE remains the same. Equal kwh energy as now. And is simply rewired so half the Ah, double the volts. When volts are doubled, the Amp draw at any comparable speed halves. So range remains unchanged. But if you also shorten the gearing, then Amp draw drops by half at the motors too. And so further gains in range are acquired for 'free'. With the SAME battery size.

You would need a different charger(s) or a BMS to do it simply, but higher voltage controllers are available. And the motors don't care and will in fact run cooler at lower amps and lower torque loading.

[Williamclark77]

I've been slacking doing updates. A lot is completed. It just doesn't look like much in pictures. I started the painting and coating. Should finish that this weekend and start the fun wiring part shortly after.

A few quick cellphone snaps.

60ah, 50.4 volts (46.5 working volts)




Left side setup. Don't think I posted a picture of it


Swingaway joystick mount. The aluminum piece is the tension adjuster. I'll machine it down and put a neat shape on it. It works like a clutch on three plastic washers/clutch discs, spacers, whatever you want to call them that I 3d printed. Works good. The small joystick is actually a four position rocker switch. It controls the tilt and feet extension.



Joystick housing top. Crap picture. This came out really nice. I made it from a semi flexible plastic that give it a good feel. Snaps on tight. Doesn't really have to have screws but it will have some from underneath that are hidden.



Just sitting for fitment check. Perfect. Forgot to take pictures of the housing I made.



Feetrest fitup



Tack weld it in just the right spots and use a big enough crescent wrench and even crap quad hands like mine can form 1/8" thick steel





Welded out



Five minutes with a flap wheel and smooth edges all over. A few pin holes. They'll be filled



Feetrest mount. It slides on a tube to adjust the height. PITA to make.





That's it for now. I've done more, just haven't gotten around to taking pictures.

[Burgerman]

Is this meant to be armored against shells? Those are going to outlive your great great grand kids! Pod is cool!

[shirley_hkg]

I have the same thinking too , that the chair will be ultra heavy with all those thick steel parts .

It's a typical American built .