Mag Max: compact 2-stage drive /w mag clutch brake regen

[j3tch1u]

Output shaft Matex part #U75-907.

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[j3tch1u]

Bearing block using double stacked NSK-6301 37mm OD radial bearings. Gearhead assembly bolted together with 8 stainless steel M4 hex cap screws.

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[j3tch1u]

Needle thrust bearing. 20mm OD stainless steel shaft collar provides better surface contact for 1-way clutch bearing.

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[kfong]

Excellent, that was what I was envisioning for my Currie gearbox. The motor I have is longer, so I was planning to put the gear box along side it, with a chain or belt to connect to it. How did you get the second stage connected to the first stage or are the matex gears setup to stack? Looks like I will need to create a connecting rod between my two stages and was thinking I might need to have bearings on that connecting rod. I like the cooling fins you put in. I'll have to remember that when I do mine.

[j3tch1u]

Fixed sprocket and freewheel. 1-way clutch bearing press-fit onto threaded adapter. Fixed sprocket and freewheel torque in opposing directions so they lock tightly together under motor or pedal power.

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[j3tch1u]

Locking cap with needle thrust bearing fixes the dual freewheel assembly in place. The motor drive is now ready to mount.

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[j3tch1u]

Excellent, that was what I was envisioning for my Currie gearbox. The motor I have is longer, so I was planning to put the gear box along side it, with a chain or belt to connect to it. How did you get the second stage connected to the first stage or are the matex gears setup to stack? Looks like I will need to create a connecting rod between my two stages and was thinking I might need to have bearings on that connecting rod. I like the cooling fins you put in. I'll have to remember that when I do mine.

the matex gears "mate" together--1 side is female and the other is male it will not be easy to attach pulleys on these gearboxes--you will need to find someone to broach the pulley for you. you will also need bearings to support the sun gear. If you went single stage with that HXT it would still fit between the cranks.

[12p3phPMDC]

Thanks for posting those inspirational assembly pics!

[kfong]

Thanks for the info, now I have a some idea of what I need to do. I still want to try putting them side by side. I like the setup as narrow to the frame as possible. I'll have to put bearing blocks for the sideloads and will use a freewheel and chain, but plans may still change as they always seem to do.

the matex gears "mate" together--1 side is female and the other is male it will not be easy to attach pulleys on these gearboxes--you will need to find someone to broach the pulley for you. you will also need bearings to support the sun gear. If you went single stage with that HXT it would still fit between the cranks.

[j3tch1u]

Thanks for the info, now I have a some idea of what I need to do. I still want to try putting them side by side. I like the setup as narrow to the frame as possible. I'll have to put bearing blocks for the sideloads and will use a freewheel and chain, but plans may still change as they always seem to do.

You could cut one of these couplings in half (Matex part #U75-902) and bolt them onto your pulley or alternatively use a Shaftloc type bushing.

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[j3tch1u]

Thanks for posting those inspirational assembly pics!

np 12p. i hope others find it useful and even improve on the design.

[j3tch1u]

original thread: viewtopic.php?f=14&t=15408

this is a first cut of my monoblock termination cap. it is for a 12s pack. the material looks like kraft chedder (not sure what it is called) but it is cheap and my machine cuts thru it like cheese. after i nail down the feed rates and optimize tool paths, i'll cut one out of delrin for better durability.

the cells fit thru slots in the back and stack on top of each other without any spreaders. there are thru-slots for the tabs which are folded over each other and clamped with a 3mm copper plate. i may add 1.2mm flat springs (with slight curvature) to even out the contact pressure of the tabs and eliminate any possible voltage drop. in the middle of the block are channels for the balance wires. there are grooves in the back along the outer edge to secure 2mm carbon fibre panels for the housing. a matching end cap will lock the assembly together.

assembling each cell is very fast, safe and solder-free.

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[j3tch1u]

12s fechter/goodrum bms v2.2 mounted.

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[recumpence]

Ahh, it makes me smile.

Matt

[johnrobholmes]

Oh yeah! glad I ran across this build! What kind of efficiency do you expect from the reduction units?

[12p3phPMDC]

http://www.matexgears.com/index.html

From Matex:

"High Efficiency
The module design ensures that the planets in the Matex gearset always share equal loads, resulting in 98% efficiency at a single reduction and minimal heat loss and noise. For each additional reduction step, efficiency loss is only about 3%.
"


So I would say the j3 two stage planetary drive is at 95% efficiency.


j3, awesome job on the battery assembly!!!

[j3tch1u]

So I would say the j3 two stage planetary drive is at 95% efficiency.
j3, awesome job on the battery assembly!!!

that sounds about right--they feel very smooth. lubed vs unlubed also makes a huge difference in noise. imho, these gears are a good alternative to belt-drive reductions.

[johnrobholmes]

If only the average person could mate them up! Looks like you have above average means there

[j3tch1u]

8 gauge terminal wires and balance taps connected.

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[j3tch1u]

Aerial view. Still need to make a top cover that integrates the cell-logs, XLR charger plug, mains plug and kill-switch. I'm thinking thick polycarbonate.

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[cell_man]

Looking really good Ben, lovely work Fancy making a few more of the battery packs

[bigmoose]

Ditto's Ben. Very elegant design and execution. The cleanliness of your assembly and machine tools is impeccable! You must have worked in the nuclear industry or in medical implants?

I have always liked the packaging of a two stage planetary. I look forward to your efficiency findings and durability report. I wish there were more "stock" planetary parts available for integration into unique/custom power heads. Great thread, great build.

[j3tch1u]

The cleanliness of your assembly and machine tools is impeccable! You must have worked in the nuclear industry or in medical implants?

or just really anal-retentive

thank you for the encouraging comments guys, i don't know what to say

haha they better not let me near isotopes or breasts..i'd run amok. actually i studied industrial engineering but ended up starting an internet company (this is me http://en.wikipedia.org/wiki/Ben_Chiu). my anal-retentiveness was probably trauma induced--coding 1.5M lines of C++ for our search engine. ahhh the good old days when Java was but a twinkle in Sun's eye. i'm gonna go reminisce now

[j3tch1u]

Looking really good Ben, lovely work Fancy making a few more of the battery packs

you get #0002 off the production lot

i know a prototyping house that will do small runs..but it may be a while before i'm ready to pull the trigger on a final design.

i suppose your time-frame is "yesterday". maybe offer a dev-kit monoblock pack to active es contributors and low-cost, low-hassle, low-man-hours pack to everyone else?

integration is very time consuming and labour/service intensive. if i were you, i'd just focus on moving as many loose cells i could and ramp that volume up. try to reach a point where "the company that shall not be named" would sell to you in case your other source dries up.

[johnrobholmes]

Very sound business advice there, and it looks like your life has been pretty interesting up to this point Mr. Chui


Can't wait to see what you do next, this is quite the clean build. There is elegance in all of it.