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TDCM DD-hub/IGH hybrid

Posted: Sep 14 2014 12:07am
by spinningmagnets
Edit: Justin is reporting that his initial order of these have a 30mm wide stator, and the spoke flange diameter is 210mm, so the outer shell is approximately 22mm smaller than the common Crystalyte H35 (@ 232mm), for reference, one inch = 25.4mm

TDCM is currently best-known for their torque-sensor BB-crankset. At the Interbike 2014 in Las Vegas (Sept 9-13), they had a prototype of their new hub-motor. The rep was not fluent in English, but the hub has a 5-speed IGH built into the center of a direct-drive hub-motor, and the rep said that they are working on a 7-speed IGH that will retrofit this model.

Since it doesn't need to allow space for a 7-speed gear-cluster, the stator has the option to be fairly wide, and 45mm would easily be an option for this style (Crystalyte is still making 40X's for ebike.ca's "stokemonkey", with 40mm wide stator). I was told they will be available for purchase in October, and I would definitely use a full-suspension frame on this, to help avoid taking a chance on breaking axles and spokes. [The axles and spokes may be very strong, I'm just saying there is no road data published yet]

He said the proprietary disc brake is a one-piece (no separate spider), with a non-standard 4-hole interface (seen in pic).

http://www.bike-eu.com/Home/General/201 ... -1121409W/

click on pic for hi-res:
Interbike3 020.JPG
Interbike3 021.JPG

Re: TDCM DD-hub/IGH hybrid

Posted: Sep 14 2014 12:42am
by johnrobholmes
wire exiting from slot instead of axle, nice. integrated torque arm for the igh, and maybe maybe maybe the motor too? That would be rad!

Re: TDCM DD-hub/IGH hybrid

Posted: Sep 14 2014 1:38pm
by cycborg
Nice concept; that's a good use for the wasted space at the center of a DD hubmotor. I'm curious about the implementation - someone needs to buy one and post a teardown!

Re: TDCM DD-hub/IGH hybrid

Posted: Sep 14 2014 6:42pm
by Gregory
I love the concept too. But I bet it's going to be expensive.

Re: TDCM DD-hub/IGH hybrid

Posted: Sep 17 2014 9:10am
by docnjoj
Those gears replace the freewheel gears, right?. Can it be shifted standing still? That would be a big plus.
otherDoc

Re: TDCM DD-hub/IGH hybrid

Posted: Sep 18 2014 8:47pm
by ARod1993
That's amazing; now I'd just like power and cost figures when they come out.

Re: TDCM DD-hub/IGH hybrid

Posted: Sep 22 2014 12:03pm
by BarkMau
Interesting concept, seems like the natural integration. More expensive for sure, gotta pay for all that R&D.

Re: TDCM DD-hub/IGH hybrid

Posted: Oct 02 2014 11:48pm
by waynebergman
Interesting look to the 3 cross lacing pattern (or maybe this is called a 4 cross in this case) I am confused none the less. Looks like the rim has 4 eyelets grouped close together and then big spacing between that group and the next group of 4.

I sure like the idea of the internal gearing. Awesome! I hope it works well.

Re: TDCM DD-hub/IGH hybrid

Posted: Jul 19 2015 6:51pm
by spinningmagnets
Cross-post from Justin-LE here http://endless-sphere.com/forums/viewto ... 5#p1073165
Regarding the large brake rotors, we've recently been playing with samples of the TDCM IGH hub motor which has a 5 speed sturney archer hub built in it. I was a bit miffed to see that it used an odd and obsolete standard 4-bolt disk rotor, but they said that was necessary since the hub geometry needed the larger diameter diameter here, which uses a 40mm ID ball bearing
Apparently the Rohloff hubs are in a similar situation and also use this. It's got a 65mm BCD, versus just 44mm for the 6bolt ISO standard disks, and that would fit around even the 45mm ID ball bearings. So if an increasing number of conventional bike and ebike parts are using this 4-bolt 65mm BCD disk, then it might be raised from the ashes again. Kinda like how hub motors have totally revived the previously dying screw-on freewheel industry.
Image

Image

Re: TDCM DD-hub/IGH hybrid

Posted: Jul 20 2015 6:45pm
by justin_le
FWIW I put this motor up on the simulator a few months ago too. It's only the 305rpm version that we got which is their 'high speed' model for the US market, the standard winding would have a lower kV:
TDCM on Sim.jpg
TDCM on Sim.jpg (64.01 KiB) Viewed 10654 times
And here is the actual firsthand dyno test data at 36V. It's a reasonable decent hub DD hub motor for sure. I've been having some discussions with TDCM about the possibility of getting an option with 0.35mm laminations, although their engineers have said the difference in efficiency is so slight it's not really worth it. Given that this has just 16 magnetic pole pairs, it's true that the eRPM is less than other DD motors and so the gains of thinner laminations for a given motor RPM won't be as high.
TDCM Dyno Data.jpg
TDCM Dyno Data.jpg (105.88 KiB) Viewed 10654 times

Re: TDCM DD-hub/IGH hybrid

Posted: Jul 20 2015 7:52pm
by spinningmagnets
What would the "average" cost increase be if they switched from 0.50mm lams to 0.35mm? Engineers are constantly baffled why customers pay good money for "upgrades" that are barely beneficial, and yet...

Chinese hubmotor engineers already think the North American customers do stuff that's nuts. If it's only $10 per hub, it would be worth it for advertising purposes alone. 60V applied to the slower Kv version would increase the RPMs, maybe closer to showing a measurable benefit at that point.

Re: TDCM DD-hub/IGH hybrid

Posted: Jul 28 2015 10:05pm
by justin_le
spinningmagnets wrote:What would the "average" cost increase be if they switched from 0.50mm lams to 0.35mm? Engineers are constantly baffled why customers pay good money for "upgrades" that are barely beneficial, and yet...
I dunno if it's supposed to be confidential or not, but what I was quoted is definitely less than the $10 per hub threshold you suggested. My main interest in thinner laminations has little to do with the motor efficiency (no one could actually discern any performance or range difference between say 88% or 90% peak eff) but with the reduced drag when you are pedaling with out the motor. At normal biking speeds eddie currents can easily be about 50% of the core losses that cause motor drag, and going to 0.35mm can take a big chunk out of this and allow the motor to freewheel better.

Then rather than marketing as 2% more efficient, you can sell it as 30% less cogging drag. A Bigger number and one that is also more discernible to the user.

-Justin

Re: TDCM DD-hub/IGH hybrid

Posted: Jul 28 2015 10:20pm
by spinningmagnets
Then rather than marketing as 2% more efficient, you can sell it as 30% less cogging drag
Thank you so much for that! I've been curious for a long time...

Re: TDCM DD-hub/IGH hybrid

Posted: Mar 31 2016 4:33pm
by handbaked
Anyone actually got one of these yet and willing to gove insight into how good it is in the real world?

Re: TDCM DD-hub/IGH hybrid

Posted: Jun 01 2016 12:00am
by spinningmagnets
I thought this was a very original idea, but...apparently SRAM had a hub called the Sparc, which had a 5-speed IGH in the center of a geared hub. Its not geared in the sense that we are familiar with. It has two tiny motors near the rim, each driving it's own geared reduction. Their two outputs are on each side of a larger single gear that transfers the power from the two small reductions to the hub shell.

Click on this page, and scroll all the way down to the bottom. I'll format pics and post them here after I get home from work.

http://www.rideyourbike.com/sramIGH.shtml

after a quick Google:
200 Watts, 200W and AFAIK a pedelec only
5-speed gearhub with 251% range
NiMH, 16.8V, 8-Ah

This system was used on the Dahon Roo Electric folder, it comes in 4 versions. first there is a European version that is higher speed than the US version which is limited to 20mph. Each of those come in two different gear ratios one set for 20" wheels and the other for 26"

Re: TDCM DD-hub/IGH hybrid

Posted: Jun 14 2016 4:41am
by justin_le
spinningmagnets wrote:I thought this was a very original idea, but...apparently SRAM had a hub called the Sparc, which had a 5-speed IGH in the center of a geared hub. Its not geared in the sense that we are familiar with. It has two tiny motors near the rim, each driving it's own geared reduction. Their two outputs are on each side of a larger single gear that transfers the power from the two small reductions to the hub shell.
Yes, I remember that motor too going way way back, ~10 years. I hadn't actually seen the Sparc internals until following your links just now. It's nice too see motor assembly completely outside the box of conventional planetary geared systems which is all we see now. But it also doesn't look like especially good use of the volume inside the motor shell,
sparcguts1.jpg
sparcguts1.jpg (80.73 KiB) Viewed 9110 times
handbaked wrote:Anyone actually got one of these yet and willing to gove insight into how good it is in the real world?
I'm not sure why there haven't been any user posts on ES about the TDCM IGH motor, but all the direct feedback we've had has been pretty excellent. It's just like having a decent ~9C power level direct drive motor with an internal geared hub in it, works exactly as you'd hope or expect! Motor performance is exactly as shown on the simulator. The only real annoyance is that it uses a special 4-bolt disk rotor like the Rohloff hub, and we've had zero luck trying to find an affordable wholesale supply of compatible disk rotor.

Re: TDCM DD-hub/IGH hybrid

Posted: Jun 16 2016 5:05am
by panurge
Hey Justin
justin_le wrote:I'm not sure why there haven't been any user posts on ES about the TDCM IGH motor, but all the direct feedback we've had has been pretty excellent. It's just like having a decent ~9C power level direct drive motor with an internal geared hub in it, works exactly as you'd hope or expect! Motor performance is exactly as shown on the simulator. The only real annoyance is that it uses a special 4-bolt disk rotor like the Rohloff hub, and we've had zero luck trying to find an affordable wholesale supply of compatible disk rotor.
Yes, there's a lack in the TDCM reports, so, it's really nice to hear it works as expected with no major issues directly from you!!!! I'm tempted to get one.... :wink:
About the rotor, I will check the next bike shows for asian manufacturers for rohloff discs....(supposing it is not the old CODA pattern), seems Hope mini-moto rohloff are the ones to try source at the best price, actually, the cheaper among the top brands..

Re: TDCM DD-hub/IGH hybrid

Posted: Jun 16 2016 9:55am
by bobc
Justin - do you not get your own components laser cut? disc brake rotors are a no brainer - I made me a rohloff one for £10 from 2mm stainless.
Seriously, chain sprockets (any sort of chain) toothed belt pulleys, brake rotors, if you can do any sort of CAD you an make these things (and brackets and housings etc etc) professional quality, 1 or 2 day turnaround, cheaper than you can buy the material to DIY. A chainring takes just minutes to design.

Re: TDCM DD-hub/IGH hybrid

Posted: Jun 16 2016 4:04pm
by justin_le
bobc wrote:Justin - do you not get your own components laser cut? disc brake rotors are a no brainer - I made me a rohloff one for £10 from 2mm stainless.
We get a ton of stuff laser cut and were considering this, but I thought disk rotors all have a ground tight tolerance surface finish and flatness and we don't have any surface grinding equipment in house. Did you just leave the 2mm metal plate stock as-is or did you surface it after the laser cutting?
panurge wrote:Yes, there's a lack in the TDCM reports, so, it's really nice to hear it works as expected with no major issues directly from you!!!! I'm tempted to get one....
They are quite nice machines, the only slightly unexpected detail on the installation is that the motors have a special anti-rotation key that indexes into part of the stator, and it's super important not to loose that piece. The actual hub axle is part of the sturney archer IGH and doesn't have any motor torque transmission on it.
TDCM_TorquePlate.jpg
TDCM_TorquePlate.jpg (52.97 KiB) Viewed 9015 times
About the rotor, I will check the next bike shows for asian manufacturers for rohloff discs....(supposing it is not the old CODA pattern), seems Hope mini-moto rohloff are the ones to try source at the best price, actually, the cheaper among the top brands..
We checked a number of booths at the Taipei show a couple months ago and were surprised not to find any that had this stocked, but we didn't look to exhaustively. If you do find something we'd be quite interested and could help organize a bulk order.

Re: TDCM DD-hub/IGH hybrid

Posted: Jun 16 2016 5:20pm
by bobc
Hey Justin,
I've made discs for a couple of greenpower race cars and a bike. 2mm is a little thicker than a standard disc I think, but the material from the laser place has always worked excellent & I've never had a problem fitting them into a standard cable caliper with new pads. (i.e. in practice 2mm doesn't seem to be too thick)
I never went for fancy shapes or vents, slots or holes, just plain annular discs with forward facing spokes, Obviously the opportunity is there to put your company logo in the profile, same goes for chainrings.
The local laser place I use has a "trumpf" machine & this routinely gives accuracy near 1 thousandth inch, and usually turns stuff round in 3 or 4 days.
Bob

Re: TDCM DD-hub/IGH hybrid

Posted: Jun 16 2016 5:49pm
by spinningmagnets
I seem to recall when reading about car disc brakes, the slots are most useful for "wiping" water away from the faces of the disc as quickly possible (one of the functions of tire tread in the rain, the valleys give the water a nearby place to go).

More metal mass in the disc is good for absorbing sudden and temporary heat, then shedding it over time. Once the mass of metal is "heat soaked" it reaches a stasis of "heat in/heat out" if you are on a long downhill with frequent braking. A while back, someone mentioned that it "doesn't make sense" to upgrade to bigger discs, when you can already lock-up the wheel with the smaller disc.

I would reply that it depends on how often you are braking. If you can lock-up the wheel with a small disc and also the larger disc, which one can absorb more heat before experiencing fade? Give me a choice, and I will try the thicker disc, and also larger in diameter if I can have that too.

Re: TDCM DD-hub/IGH hybrid

Posted: Jun 17 2016 2:34am
by bobc
"I seem to recall when reading about car disc brakes, the slots are most useful for "wiping" water away from the faces of the disc as quickly possible"
sorry to be a cynic, but I think they're most useful for separating customers from their dollars...... :)
I believe the technical justification in cars involves "gassing" from the braking surface , & the pads "hovercrafting" instead of biting. No idea if it's real or mostly BS, cycle pads are much smaller, I suppose pressures are similar?

Re: TDCM DD-hub/IGH hybrid

Posted: Jun 17 2016 2:39am
by spinningmagnets
Ah! bobc, you have refreshed my ageing memory. Yes...off-gassing from the pads. The water is flung outwards when the disc is spinning fast, so it is the gas generated by hot pads that causes "fade". I stand corrected.

Re: TDCM DD-hub/IGH hybrid

Posted: Aug 05 2016 10:36am
by spare_tire
justin_le wrote:the motors have a special anti-rotation key that indexes into part of the stator, and it's super important not to loose that piece. The actual hub axle is part of the sturney archer IGH and doesn't have any motor torque transmission on it.
TDCM_TorquePlate.jpg
I guess then all the torque arms that Grin sells doesn't work with this motor. How strong is the provided torque arm, in comparison ? Can it safely do regenerative braking ?

Re: TDCM DD-hub/IGH hybrid

Posted: Sep 20 2016 2:06am
by spinningmagnets
Until I get my hands on one, my "best guess" about this motor is that the stator is 182mm diameter and has magnets that are 30mm wide. Initially, I was not too impressed at first, but...now that we can add many more amps due to the existence of statorade (Ferro-Fluid/FF) and also motor-case fins...This motor might survive 52V X 50A = 2600W...only time will tell.

I think this is a great option for vintage bicycles, because mid-drives are very problematic to fit a curved downtube...