SRAM Patent Shows Compact Motor x Battery Unit

Apr 5, 2024 at 8:58
by Jessie-May Morgan  
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A recent patent from SRAM depicts an all-new e-bike motor design that is quite the departure from the Brose-powered system that debuted last fall. The patent itself centers on the positioning and arrangement of battery cells, which seem to be located within the motor casing itself, or at least very closely sidled up against it. Placing weight so low on the bike would be advantageous, certainly for a full suspension mountain bike, where handling is massively affected not just by overall weight, but by where the mass is located.

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Potential charging ports on the top tube (214), seat tube (212) and downtube (210)
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A USB-C charging port (162) is clearly shown on the battery in Fig. 4 and Fig. 6


Notable is the method of charging; the patent reads, "Charge current may come from a DC source, or the charge current may be supplied from any USB C power source. This allows consumers to have a single standardized charger for their phone, laptop, and electrically powered bicycle". It's also clear that the battery is to be removable, and can also be used to charge other devices like a phone.

While useful, charging via USB-C isn't all that exciting. However, what's of greater interest is the arrangement of the motor unit itself. It's super compact, with all of the hardware sitting concentric to the bottom bracket.

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Most eMTB drive units take on an oval shape, having much of the hardware necessary for the reduction ratio (converting pedaling cadence to the electric motor's rpm) sitting offset to the stator. The SRAM Powertrain, powered by Brose, is one such example. It is a full-powered drive unit with a maximum torque of 90 Nm and a peak power output of 680 W, and it is the engine room of bikes like the Nukeproof Megawatt, Transition Repeater, Gas Gas ECC and the Propain Ekano 2 CF.

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Bespoked 2023 - c by The European Bike Project

There are some mid-powered e-bike motors that are the exception to that rule. Namely, the TQ HPR-50 and the Free Flow Technology FF60. Both run on a similar Harmonic Pin Ring, or Strain Wave technology, that allows the stator to sit inside and concentric to the hardware carrying out that all-important reduction step between the rider's cadence and the motor's rpm. What we see in this recent patent from SRAM is a not dissimilar layout.

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Though we can't see inside, it's clear that the drive unit itself is cylindrical in shape, and far more compact than the full-powered Powertrain. While SRAM has leaned upon the Brose technology for its first foray into the world of eBike motors, it'd be naive to assume they weren't tinkering away on a design of their very own. This could be our first glance at that system.

Though there's little to be gleaned at this stage, I'd hazard a guess that we may see a new motor from SRAM in the next few years that takes on this more compact shape, that is lighter than the 90 Nm Powertrain, but also much less powerful - likely in the region of 50-60 Nm.

We did reach out to SRAM for comment, but they decline to comment on patent applications.




Author Info:
jessiemaymorgan avatar

Member since Oct 26, 2023
70 articles

142 Comments
  • 116 3
 This is part of the direction I’d like to see ebike’s go. Next up, universal mount standard, a fully water proof unit and the option to buy replacement internal components. Though, by the time this happens I’ll likely be dead.
  • 13 1
 If anyone manages to convince frame manufacturers of a universal standard, it would likely be Sram. Doubt it will happen for a long time given the diversity in the marketplace currently and the rapidly evolving tech.
  • 29 1
 Our best hope is the EU throwing down some ebike regulations next and hope it pressures manufacturers to swap over globally
  • 1 0
 And you probably have another 50 years to go...
  • 9 0
 I'll take a Pinion MGU with some small improvemnts. I'm hoping that's not my next bike, but the one after that.
  • 18 1
 This. I view all current ebikes as "beta" products that unfortunately will end up in landfills once battery/motor tech evolves and components are "retired" in favor of new designs.

Cybertrucks, if you will...

Need more interoperability, standardization, and repairability.
  • 3 0
 We’re there already and have been for some time it’s just a matter of someone putting the whole package together.
  • 1 1
 no worries University of Virgina has scientifically proved we reencarnate... so thinking ahead it's fine Wink
  • 2 1
 Looking Good! Smaller, quieter and lighter without Big boost and turbo modes are the future..
  • 5 7
 @ridedigrepeat: Anything related to rear derailleurs should not be bothered to be part of a "universal standard" for e bikes. This patent design is dependent upon rear derailleurs and therefore it is complete garbage that will have nothing to do with the future of e mountain bikes. Amazing how many idiots there are out there that don't realize this fact. We will have nothing to do with this bullshit outdated technology, this is just idiots at SRAM wasting company resources by pretending the derailleur will continue to be relevant for e bikes.
  • 1 0
 @robotdave: Do not incur the wrath of Lord Elon!
  • 2 0
 Planned obsolescence won´t allow for these 3 "innovations" unfortunately but that would be awesome.
  • 1 0
 @robotdave: Cybertrucks? I don't follow.
  • 2 3
 the future is NON ELECTRIC, just like for cars
  • 4 0
 @RedBurn: I'd like to see how you post dumb comments in this "NON-ELECTRIC" future.
  • 1 0
 @Chuckolicious: Beta product not actually ready for mass production but still released to the public.
  • 1 2
 @HPdeskjet3630: You're real cute with your comment. Just because @RedBurn doesn't drink the EV and E-Bike coolaid doesn't equate to a "dumb comment", just a free thinking statement.
  • 1 1
 @robotdave: Beta? I have two friends that have them, totally great. No issues. Not even a loose pedal cover. Mass production? They're literally ramping up and many hundreds are going out the door every week, likely thousands now. I still just don't follow?
  • 1 0
 @Chuckolicious: Nope, you don't.
  • 1 1
 @robotdave: Ahh, most helpful. Thanks!
  • 1 0
 @Chuckolicious: Bro, I'm here to discuss bikes, not cybertrucks.

If you really think those turds are production-ready, I'm obviously not going to change your mind in the comments of a mountain biking website.

I apologize for hurting your cyberfeelings ✌️.
  • 1 0
 @robotdave: Yet you literally are the one who decided to discuss them, I only responded with my personal experience. What’s wrong with you?
  • 61 4
 I'd rather have a gearbox in that place instead of the battery.
  • 12 3
 Right. I repeat myself. Make it Motor-Gearbox-Battery combined with Beltdrive. If it is not a 5 figure price, sweet.
  • 15 1
 Pinion MGU is what you need
  • 20 2
 @Ben-256: Bro that's called a motorcycle
  • 2 0
 Decathlon is now using the integrated Owuru motor/gearbox. I don't question the Pinion unit is stronger and more reliable but at least this is another option that's out there.
  • 5 1
 Yup or a gearbox in that place instead of a motor AND battery Wink
  • 2 0
 @chooen-tebakur: Fair enough. Without my arthrosis in both knees, i would love it without motor and battery. Sad but true. No pity.
  • 1 0
 Yep might as well, gearbox makes so much sense.
  • 53 3
 Don't worry they absolutely will continue to include the $900 derailleur and $500 cassette in their plans.
  • 4 1
 True, but I also think they'll have mechanical transmission in about a year... fingers crossed.
  • 2 6
flag PHX77 (Apr 5, 2024 at 13:23) (Below Threshold)
 The GX derailer is $400 retail and the GX cassette is $250 retail. I recently got each brand new for $50 less than retail at a retailer.
  • 9 0
 @PHX77: what a bargain!
  • 2 1
 Rohloff, 3 years without Problèms, i just changed Pinion, One oïl change a years and it's donne....
German enginers>murican marketing
  • 1 0
 @f*cktoryteam: check this out for both at the same time:-
www.youtube.com/watch?v=e-ig-R65yHg&ab_channel=ToutTerrain
  • 30 6
 I bought a SL ebike last year at 57, it's put a lot more pleasure into my riding. Looking forward to see these develope over the coming years
  • 15 8
 I'm 20, but I'm still very excited for ebikes to keep getting lighter. The prospect of a 170mm enduro bike with a bit of assist that handles just like a non-electric enduro bike is very intriguing to me, as full-power ebikes have a very "point-and-shoot" type of feeling in my experience that is quite the departure from, say, a transition sentinel or spire.
  • 12 6
 @spencerimre: I bought a kenevoSL for my 30th and it’s been pretty much exactly that. Often ride it with the motor off, when riding with friends, can add some power for the later laps in the day. When riding solo after work, trying to beat sunset, full turbo to the top. Just been so versatile.
  • 8 6
 @bonfire: that's what I've got, great bike and rides better than my Annalong
  • 9 16
flag corerider (Apr 5, 2024 at 17:41) (Below Threshold)
 @spencerimre: At your age I would focus more on the fitness and grinding up. It will do you a lot more good in the long run, trust me. Fitness has far more benefits other than the obvious. Fit guys last longer.....not just riding.
  • 3 2
 @corerider: Well by that logic every man should be in the gym twice a week, and yet 90% don't even walk to the shops. I think we'll be fine. Also check your heartrate riding up vs down, if it's bludflow you care for my heart's working 30% harder on the downs.
  • 5 0
 @ompete: Is Anna Long okay with you disclosing on here how well she rides?
  • 2 0
 @commental: LOL, didn't check the spelling on that one!
  • 3 5
 I bought a Meta v5 last year. I’m 57. It’s not an e-bike. It gives me a lot of pleasure apart from the climbs on the 1000m 40km days. Age is not an excuse…
  • 8 1
 @professed: here's that attention you ordered sir
  • 1 1
 @spencerimre: Good luck affording anything like that in your 20's
  • 20 1
 Nice, 30 AA batteries.
  • 10 0
 That's all Tesla does. "Our battery system – or Energy Storage System, as we like to call it – is comprised of 6,831 individual Li-ion cells."
  • 6 1
 @BermSkid72:

Yea 18650s or 21700s or even 4680s now. Cylinders are the best format for these batteries
  • 9 0
 If they manage to fit 30x 21700 cells in this package, they get close to 600Wh of Energy. This would be a fairly big battery. And even if they can only fit smaller 18650 cells this would still get them around 360Wh. For a SL eMtb this is pretty good.
  • 3 0
 @Rossfeld-biker: In the image I counted 40 cells so that's right at 400+ wh which is right in the range of existing SL bikes out there. Using 21700 would be really exciting at ~800wh. Weight is down low also which seems like a good thing.
  • 2 0
 @ryan77777: Diameter of the cells looks close to the diameter of the crank axle, so I was already assuming 21700's
  • 2 0
 If you remove them they'll be speed holes and you'll go faster
  • 1 0
 @G-Sport: Ah, good eye! 800wh on a 'SL' bike would be crazy good
  • 1 0
 @ryan77777: But with current energy densities 800Wh is far from light...
  • 2 0
 @HankHank: And if you could side the cells in and out as you ride, your bike could sound like a pipe organ!
  • 12 0
 This looks like sub-optimal arrangement for a good thermal management of the battery. Having some cells just millimeters away from an high heat source like the motor will significantly accelerate cell aging and overall battery longevity.
  • 5 1
 Do not worry, it will have a radiator.
  • 3 0
 @alwayslivingthedream: Only suitable for frames where you can run a water bottle?
  • 12 2
 I'm impressed, this article has survived over 30 minutes without hateful comments related to EMTBs.
  • 11 3
 I, for one, welcome our new electronic overlords.
  • 7 1
 I'll play along.

This patent and other activities like it are precisely WHY all of the components and bikes you see coming out are so expensive. Nobody wants to get left behind in the dark ages, so everybody is staffing and funding projects for e-development and the burden of that R+D cost falls on the whole business.

E-bikes are costing all of us money, whether we try to opt out or not. It's inescapable because even small builders who aren't involved rely on giant component makers who ARE involved. It feels like a bullet train headed towards the industry having an identity crisis and wreaking havoc as some companies pivot towards powered personal mobility and recreation over time and others cling to bicycles.

Wasn't Honda's first vehicle a pedal-assisted bike? Now they build cars and jets and other companies build bikes. Maybe in the future SRAM will be an electric motor supplier for the military and have a line of madmax motorbikes, and TRP or ZTTO will supply all the bicycle parts. IDK.
  • 6 6
 @hotpotato: I’ll play along too. Ebikes are here because there’s a demand and now they are as good or better than analogues, the industry is fighting to to stand out in the crowd. I don’t think any manufacturers out there, don’t benefit from having an e-bike development team and analogue bikes are benefiting from stronger and more powerful brakes, that wouldn’t have been mainstream, before e-bikes.
The trickle down advancements are starting from e-bikes now, not the other way around. Thanks e-bikes
  • 2 2
 @lev3000: I can see where you're coming from, but I don't buy the "stronger and more powerful" parts argument.

Your average DH/Enduro racer...even racing at the "Expert" level, let alone "pro"...puts far more stress on components than the average ebike rider putzing around on flow trails.

"What about strong riders on ebikes?" I'd counter that the average 160 - 180ish lbs male rider in Europe/NA on an ebike weighs the same as someone built like Richie Rude (200 lbs) on a regular bike. So in reality most of these "e-bike" edition products are full-on product marketing BS.
  • 4 1
 @robotdave: I think your example is right, but there may be a perceived need for stronger more powerful stuff. The 38mm fork is an example. I think their (not sole) existence is down to e-bikes and I think analogue bikers have done well out of it!
  • 1 1
 @lev3000: Yup same page. Product marketing BS is a game of perception Wink .

In conclusion...BRING BACK THE TOTEM. 40mm or BUST!
  • 1 5
flag corerider (Apr 5, 2024 at 17:44) (Below Threshold)
 @hotpotato: ebikes are being pushed because they don't last and will force the users into component changes faster (think motor/battery). No secret why they are being pushed beyond the fact they are attracting users whom don't know any better.
  • 7 0
 @corerider: weird, because I have been riding MTB since 1990 and owned loads of different bikes and I also know a lot about bikes and have an eMTB now. No one forced me, it’s my preferred bike, reason being it’s more fun - which has been my motivation to ride since I was a kid.
  • 1 2
 @lev3000: You guys are paying for years of e bike hate in the Pinkbike comments and I am here to watch your expensive tears.
  • 1 0
 @hohmskullkrishten: well worth writing that comment. Well done.
  • 2 0
 @corerider: Huh? I have three friends that all still have their Gen 1 Levos and get enough battery life out of them for fun rides still.
  • 10 0
 How does one axs this?
  • 2 0
 I though you'd never axs.
  • 5 0
 Putting the cells across the frame rather than aligned with the tubes seems a great idea. Also good to use the space under the crank which current motors seem to almost fill but then leave just enough space that you cant use it as a nice bashguard to protect your chainring.
40 cells suggests 10s4p arrangement so probably a full fat bike. Be nice to see how compact and rearward biased weight distribution it could manage with half that (10s2p).
I have no real interest in heavyweight super powerful eeebs but lightweight ones are super liberating when you have no uplift options and limited time.
  • 9 0
 They are going all out not to put a gearbox in there!
  • 1 1
 Exactly, funny that they think they can compete with this shite.
  • 8 0
 I still see a derailleur Give me Pinion MGU or give me death
  • 5 1
 The concern I have with the Harmonic Pin Ring motors is that they are terribly inefficient. MTB Review did some range tests with the various motors on a consistent hill and even after normalizing for different battery sizes, the HP motors travel a lot less/ watt than the more standard e-bike motors, with the Fazua 60 consistently being the most efficient with its battery power. For the record I did the math myself, it wasn't in the reviews.
  • 4 0
 Personally, I'd like to see a universal small motor with less assistance that fits into a standard bottom bracket and uses a water bottle battery if that is possible. Then any analog bike can be retrofitted with some power. Sometimes you just want a little boost. Just my couch surfing brainstorm.
  • 3 1
 I see this design as a potential fire hazard

Riding an e-bike currently and looking how scratched up the bottom of the motor case is I’m very happy there are no batteries there on my bike and that they are higher up the down tube
  • 1 0
 Optibike built and sold this design back in 2014. IT was called the SIMBB (super integrated motorized bottom bracket) It featured a 750 watt motor and 760 watt hour battery. Check it out here optibike.com/optibike-simbb-29c
  • 1 0
 Batterie next to a hot source and just in place for Casing jumps and explode..... You'd think engineers World do it better, but they design programmed obsolescence for a big corporation.. If you want a real solution from real engineers look at Pinion
  • 1 0
 I don't ride eBikes, however, I do ride motorcycles (watermelons and grapes, I know)...
It would be interesting to A/B test this alongside a comparable bike with a battery in the down tube location to contrast handling relative to inertia and gravity.
  • 4 0
 Sorry but it looks like SAM'S effort is full of holes...
  • 3 0
 is the battery removable or replaceable? is battery in smash zone. will motor heat next to battery effect battery.
  • 3 0
 It's a SRAM patent to stop others from making the horrific mistakes of putting the batter in a smash zone. All those movies of cars exploding while falling off a cliff - well, that's gonna happen to your e-bike on Red Bull jumps. Too bad Evel Knievel isn't still alive to do those on full suspension e-bikes!
  • 2 0
 Fig 18 looks like a two stage cycloidal gear reduction. Nice compact way to get a coaxial drive. Mavic has been working on one for road and light commuter application.
  • 3 0
 Now it doesn't matter if the battery or the motor dies... either way you have to buy everything new....
  • 3 0
 One of the battery cells must be their new rear shock
  • 1 0
 Yes. It's a bomber boost
  • 1 2
 "It's also clear that the battery is to be removable, and can also be used to charge other devices like a phone."

That's clear? It looks completely integrated. I mean, the first few figures literally show it as one monolith unit...

And a USB-C connection does not automatically mean it can act as a Power Delivery host and thus supply power to a connected device. If it's not configured that way, connecting a newer phone may even try to charge the bike since "power sharing" to charge wireless headphones and such using the phone battery is common in fancy phones nowadays.
  • 3 1
 Hopefully these things really kick ass when I'm 70 years old and finally in the market for one.
  • 1 0
 Great idea but this looks like its a different shape to the current motors units and yet again here is SRAM doing its usual trick of changing a Standard to suit itself...
  • 2 4
 "Charge current may come from a DC source, or the charge current may be supplied from any USB C power source"

Terminology is important, especially in patents: "any USB C power source" _IS_ "a DC source", there is no "or" involved.
  • 2 0
 Would be incredible if ebikes went to a standardized charging cable! My laptop can charge 100w over USB C. Maybe not that fast for an ebike but I'd gladly charge slower in order to not have a separate charger for everything.
  • 1 0
 Terminology is important, yes. USB has, in it's essence, 2 data and 2 power pins, which, by the spec, provide up to 500 mA at 5 V. This is what would be called 'DC'. Part of the USB-C spec, among other things, is Power Delivery. The power supplied by it started off at something like 60 or 100 W but recently got increased to 240 W. This is achieved by using a higher voltage (I think it's up to 40 V now?) but this requires communication between the charger and the device to setup the correct PD state.

With a DC source you apply the voltage and the charged device pulls the current it wants or needs and that's it.

The negative to either variant is the fact you need a charger inside the drive unit to handle the voltage conversion and charging states and talk to the battery. This is something that is done with cars, but as far as I understand eBike drives use an external charger (the brick) to talk to the battery and do the adaptations to the charging states. This means less space is taken up and less weight added to the bike itself.

Also, I guess I should start publishing ideas, I was pithing USB-C charging in an e-bike related meeting in late 2019... -_-
  • 4 1
 Smoke and Mirrors
  • 2 0
 Figure 1 looks like a William Nealy cartoon.
  • 1 0
 It should also charge all AXS and Flight Attendant batteries at the same time
  • 1 0
 Hardly noticable. What happens in a year or two when the batteries are at 70% capacity?
  • 2 0
 Looks like the boiler off a steam train. Where do I put the coal?
  • 1 0
 Hopefully, a good heat shield between motor and batteries?
  • 1 0
 I am more concerned that the brake line goes thru the spokes on Figure 1.
  • 1 1
 Wow, this isn't going to work. I hope they are ready for thermal runaways during testing
  • 2 0
 Fire in the Hole!
  • 1 0
 Direct DC charging would be dope in a van!
  • 1 0
 It would be nice to include a patent number or a link.
  • 1 0
 What is more interesting is that the motor and crank are on the same axle.
  • 3 2
 Meh
  • 1 0
 ...Actuals
  • 6 7
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