One of the takeaways from this video is that you really have to credit the ICE automotive industry for somehow making so many highly precise and complex assemblies affordable and reliable. I never gave CV joints much thought, but looking at the precision gears and bearings and housing and parts count inside of just one component and I am simply amazed that an ICE car can move more than 10 feet before something breaks down. Hub motors are much simpler than this uni-wheel concept and orders of magnitude simpler than an ICE car. I am looking forward to never returning to my local mechanic for repairs.
I've had to rehab more CV joints than anyone would want to, and I will be glad to see them go. BUT, they are absolutely brilliant works of complex geometry, especially considering that the early ones were designed with sliderules.
I've kept a couple of classic minis alive beyond their expected lives by decades. These Uni-Wheel contraptions are obviously a pull and replace item and with the complexity I'm guessing not cheap. They remind me of the pencil vs the ballpoint pen challenge of space.
@@DeSilver215 I designed and helped build a samples freezer for the ISS, among other high tech thermal projects. I have no basic worries regarding Aptera. They have an excellent solution with 3 separate cooling loops.
In my opinion, the simplicity of the in-wheel hub motor comes out clearly ahead. This is especially true in Aptera's case, because the light weight, super aerodynamic vehicle has less power demand, and this allows for an even lighter hub motor than would be typical. In-wheel hub motors are also direct drive, eliminating any additional gearing, knuckle joints, or drive shaft. Aptera and Elaphe are the clear winners in my mind.
I came here to say just this. I’m watching this video and wondering why? We have hub motor technology so this feels like it is overly complex to an old problem. It’s like they realized this problem 5 years ago and went into a room and just came out with the solution and now hub motors make their problem, and thus their solution, obsolete.
@@johnmalcom9159 That may be true, but analysis and common sense are what we have to go on until some driving history exists. Time to develop that real world data will provide actual answers... obviously.
You don't have to go on anything. Just weight until testing is complete. You need not decide on either c solution since neither is available in the market place. He vale of either is moot at this point.
I agree that hub motors are an elegant solution. I look forward to seeing them work in the real world. I think that there are real engineering challenges around unsprung weight and lack of flexibility with gear ratios. They do work pretty good on e-bikes though 😊
On the lighter side, I very much appreciate the CV joint video with the guy using his old underwear to clean the grease. Old skivvies always enhance the cinematic experience.
The need for the effective length of the driveshaft to change in traditional driveshaft design is accommodated by the design of the inner CV joint, which in addition to changing angle can also allow the shaft to move in and out.
YASA was purchased outright by Mercedes Benz, they make in-wheel motors. That tells me it is a viable product, with a future. Elaphe needs Aptera, and a vertical integration later would be a great thing for Aptera. Thanks number 26 Steve!
Two things they conveniently neglect to mention are how they would integrate mechanical brake components in the same space as the gear assembly, and how they would seal the Uniwheel where it moves around the input shaft. It looks like a very difficult challenge for keeping lubricant in and contaminants out.
One of the biggest innovations for early electric cars was going from a 3 pole to a 6 pole motor, which effectively doubled the torque and required one less stage of step down gearing. Brushless motors from 2018 frequently had 36 poles on cinematic quadcopters. I have seen references to motors with 80 to 144 poles, which can deliver much higher torque and hence completely eliminate the need for mechanical gearing.
A perspective from a vehicle R&D engineer. First, Kudos to both Hyundhi and Apteera for taking the initiative and risk to engineer a potential upgrade to the conventional EV drive train design. Both are untried at this point. For both or either to be validly assessed as an improvement or "Best" solution it would require extensive real world driving under a plethora of driving conditions by a lot of real world customers in their own use cases over an extended time. A thought on the Uniwheel The Uniwheel has a lot of moving parts running under constant changing stress. Without the above vetting, it may prove to have low reliability with frequent faults that would cause a break down/failure. The Uniwheel reminds me of Mazda's innovative rotary engine. It works but never caught on. I wish them success as I support any improvement to make EVs work better and more efficiently.
Each wheel will also need gear oil bath. Pinion and ring gears wear out slowly if proper maintenance is performed. If maintenance is missed, pinion gears wear out quickly.
Looks like the UNIwheel has a joint on the outboard side of the shaft, which I think takes care of steering angle. Looks like it not just goes up/down in stroke but also fore/aft too so shaft can same lenght and straight.
It seems to me that they could have the electric motor rotate as the wheel turns, with the pivot point of the motor's rotation being in the center of the arc. With the uni-wheel handling the other translational motions. Hyundai would never release or announce their Uni-wheel if they had not first worked out this fundamental steering functionality. But I totally agree with you that the in-wheel motor has the advantage of more simplicity and efficiency, while sharing the uni-wheel's advantages over conventional CV joints and transmissions. With the one downside being a little more unsprung weight for in-wheel motors.
There is a mechanical advantage to the Uni Wheel over a hub motor design in that the motor can operate at higher speeds and therefore produce the same torque with smaller, lighter motors. The disadvantage comes with complexity of the system . In the eBike world, mid-drive motors running at higher speeds and torque have supplanted rear wheel hub motors because they are so much lighter.
eBikes may not be the best comparison as the drive system is such a large fraction of the total vehicle mass. Trading off a bit of mass may not be as big a deal for cars. Nevertheless if elaphe motors are close to 60kg, that does seem rather heavy. I worry about loads on the suspension system. On the flip side, how awesome would it be if you could just replace the rear wheel in 5 years and get an entirely new hyper advanced axial flux drive system (assuming a rear wheel drive model)?
Hub motor is limited on speed and torque due to space allowance; whereas the uniwheel could gear torque out of a smaller motor to lower cost of the motor. For applications requiring more torque could displace a much larger motor than a hub motor. Another benefit is motor protection; clearly having the motor tucked away on the frame and not bouncing around hitting pot holes and children will increase the longevity of it. Aptera Max speed is 105mph, I believe. With gearing in the hub, the motor would be allowed to run at higher RPMs. I absolutely love the hub motor for the Aptera; it’s a perfect match. For larger vehicles and race cars, the uniwheel might be a better solution. Btw, a small CV in the format will handle flexing for steering, they showed side to side motion in their illustration with a cv coupler. I’m keenly interested how the uniwheel handles regenerative braking.
105 MPH is fast enough unless you want to Track Race your Aptera. 0-60 in 4 seconds is fast enough unless you enjoy self-induced whiplash. Aptera and Rousch. Engineering are working hard to minimize the downside of the extra unsprung weight. Does anyone know how much the Aptera optimized hub motors will weigh vs the United States-hub?
Steve, look at 10:28 in the video and you'll see they do show a steering rack connected to the wheels but no close up of the connection. I suspect the steering rack and connections are just leftover parts of the centered power source render because the inset starting at 10:36 shows the steered wheels turning on the standard central power source but not on the uni-wheels. Perhaps they plan on using torque vectoring for steering purposes, but I don't see that being very efficient. As for their suggestion starting at 11:23 about the uni-wheel working in ANY form of transportation, I thought of the following forms: boats and ships, rail, and aircraft. They could have said "wheeled form of transportation" (though rail uses wheels).
For HEAVY vehicles requiring larger/heavier hub motors, the unsprung weight becomes a problem. Aptera manages b/c it’s light and can use lighter/smaller hub motors. There’s bound to be some unsprung weight penalty, but it keeps the front body volume minimal where it needs to be narrowing down for aero.
I love your video and is part of why I've reserved one. I was wondering if you could do a comparison video between Aptera and the solar charging Prius Prime? I think you'd you do a great job comparing the two.
The key advantage of this design is in high performance, high speed vehicles. You mentioned the unstrung mass but the bigger thing is that externalizing it allows higher performance motors and potentially a transmission to allow far higher top speeds. If Hyundai licenses out the technology I could see something like an updated model s plaid or roadster using it since the compromise in top speed for a hub motor isn't acceptable for them. As to steering I think a simpler mechanism than a CV can be used since it only needs a single rotational axis.
That sounds like it add up to mre mechanical losses of energy, require maintenance, and potential points of failure. If I could chose either option on the same vehicle I would opt for the wheel motors.
@@garywozniak7742 Not saying hub motors are bad but they will never be the absolute peak performance option. They are fast enough (even detuned for efficiency) that Aptera can match the AVERAGE Dodge Viper or Porsche in 0-60.
@@ccibinel I worked across the street from Tesla in 2008. In 2021 I had a ride in an Aptera prototype that accelerated far faster than those Roadsters did at the time (without breaking a transmission).
You had a big question about the steering with you any wheel I think what they do is the motor has to move sideways and pivot around the wheels pivot point
Thanks for the focus Steve. Too complicated for me. How many times I've fought the CV and, with enough money, won but not a fight I look forward to. The advantage of the UniWheel is one power source. Our Aptera has at least two. I wonder what the difference in cost would be? I also noticed they didn't mention the inside universal system nor the weight of this double axle assembly but our in-wheel approach isn't the battle this innovation is fighting.
At 4:20 you talk about upper and lower control arms. This configuration requires no upper control arm. The strut pictured controls the upper spindle lateral and longitudinal positioning and is a point of rotation on its long axis. The lower control arm will have its ball joint in line with the upper strut. Midway between the two, on the same axis, is the CV joint in this image to allow for steering.
So you are adding 11 gears with bearings and shafts and a ring gear. You see the small diameter of those gears. They will be screaming at high speeds. How do you keep them lubricated? I think it is a brilliant design for a slower moving vehicle, so you could have enough oil or grease in there to keep the heat down. With four of these you would be adding about 160 parts to the vehicle. I don't see that as a design improvement. Funny that uni usually means one.
I could see how it'd turn if it were on a motorcycle or an electric unicycle. If they could design this same concept in a 360° sphere/tire and utilize it on an electronic unicycle with off road capabilities they'd have a unique fun transportation device. The foot controls would be weird to get used to but the ability to strafe would be unique.
I wonder about longevity. With that many gear surfaces there would have to be lubrication, so will it be a sealed gearbox, but how do you seal a movable input shaft?
NEVS in hub drive removes the need for any drive shafts, the only thing to change in that set up to use an axial flow electric motor that is even smaller and lighter.
It allows for a transmission where a hub motor doesn't. It would also work for ICE cars. It appears to have a cv joint for turning that is smaller and normally straight while going down the highway.
At 4:00 when they discuss how it works, I see a lot of moving parts that need maintenance. Then the animation of the up and down motion and then asked to myself, what about the wheel moving forward and backwards? That assembly better be made from a strong lightweight material, otherwise it'll take a beating.
I like the concept although as you mentioned in your video more points of failure in this new Hyundai motor. I would have all the parts stamped out in Carbon fiber all the bushings and gear armature Carbon Fiber. Reduce weight increase strength. Basically your wheels are the Car so no expense should be negated in this technology. Thanks for the video.
Thanks Steve for doing this video! Hyundai has another video showing their torque vectoring and 90 degree rotation of each wheel, allowing for going 90 degree change of direction after a full stand still position. Do you know why they don't just try hub motors?
Hyundai's visuals show the uniwheel driving the front of the car. I'm guessing they've traveled the problem of steering movement at the wheels. But it's a good question how they do it.
Some problems I can see with the uniwheel, compared to a hubmotor: the friction of the gearset, lubrication and sealing the gearset from the elements, limits to suspension travel.
@@Jojo-o6o6w The hub needs a pivot to allow for steering because the motor is inboard an fixed to the subframe. That’s one of the jobs a CV joint does in a conventional FWD car and that’s what I am referring to.
@@juancarrera5524 sory i dont get it.. i have a front wheel drive truck and the steering rods have ball joints at the end of them, the CV joints are in the drive axles.
The inherited problems with inwheel motors are: * Increased inertia/unsprung weight * In order to decrease unsprung weight you might use gears with smaller motor, but then you increase complexity of the system substantially * If you go without gears, more magnets are needed to achieve desired torque values (aptera's approach), and there is more weight * Protection of the motor against shocks, dirt, water and salt ingress is still unproven technology (no oem uses it for passanger vehicles yet) * Power and cooling cables need to be supplied to the wheels, which may experience fast and large movements relative to the vehicle... how reliable can this work is yet to be proven * Often praised "increased efficiency" is debatable, it is probably under 5% compared to conventional drives I must admit that I never welcomed apteras decision to go with inwheel motors. Why opt for unproven technology that has at least as many potential drawback as advantages, for very modest efficiency gains? Why increase the risk of failing their primary concept at the market, to which it wouldn't contribute much anyway?
This hyundai approach looks it might work well combined with the axial motor type (which have higher power density then elaphe radial motor)...but of course it remains to be seen how well they resolved the protection of those gears.
@@garywozniak7742 I think they use one motor for each wheel, but they are not inside a wheel. Rather the motors are attached to wheels by (a very short) shaft (see en.wikipedia.org/wiki/Individual_wheel_drive).
Showing the complicated drivetrain is a hybrid car but the simplified vehicle is a true electric vehicle. An EV doesn’t have an internal combustion engine.
I see these being used more for higher power vehicles, hub in the front, significantly larger motors in the back Could make an excellent system for semis
This is kind of a compromise between a CV joint vice an in-wheel motors as you realized. This does allow a centralized motor rather than 2 or 3 motors in the Aptera. So if Elaph Motors are more efficient but does require electrical power connections to it so it is a valid potential tradeoff. There are ways to allow rotations at the hub.
@@jamesengland7461 Yes, but it is still a tradeoff. I think I know the result of the tradeoff, as do you. But if you come from a centralized motor paradigm, the uni-wheel concept is progress.
The thousands of contact points in those gears could be problematic as they wear over time. And as small as those gear teeth are, it wouldn't take much wear before they are out of tolerance. The assembly would have to be sealed extremely well since it operates in the vehicle's dirtiest environment, at the road. Maybe Hyundai is thinking this would give their service departments something to do on a regular basis, to make up for lower service for EVs.
At 10:28 th-cam.com/video/lGiWlf2MSX4/w-d-xo.html It looks like the front wheels steer a little bit and it looks to me like the electric motors move with them to keep a straight connection to the wheels.
Not sure if this has been addressed already, but perhaps you can steer left by manipulating the speed of the left vs right wheels: slow left wheel + fast right wheels = left turn. Just my thoughts from someone who has no knowledge of cars/gears/mechanics/etc. I'm guessing that's it's probably more complicated than that.
Each time power is passed through a gear there is friction loss. In each uniwheel there are ten gear tooth contact points of power transfer through which power is passed and a bearing on both ends of each gear wheel support shaft. Rube Goldberg couldn't have made this more complicated. In the diagram/picture at 6:50 I count 31 points of wear on each wheel plus any additional bearings to allow steering. In an all wheel drive vehicle this presents at least 124, plus any I missed, plus any steering required drive bearings, points of failure, as opposed to Aptera all wheel drive six total drive bearings/points of failure. That is a wear point trade for unsprung weight I am willing to accept. Aptera looks better and better.
I would not be so sure on a weight penalty in all cases. That ring gear will need to be pretty robust and there will need to be lubrication in the gear compartment. 11 hardened gears and associated linkages and shafts is not going to be light weight in my experience. Unless you do some expensive manufacturing for hollow shafts and optimized gear structures to reduce the weight.
Given that the drive axle is still there, with pivoting and telescoping features, and the transmission/gear reduction is just moved inside the wheel, nothing has been accomplished here except to move more sprung weight to the wheels. There's still the matter of hub bearings, lug nuts, brakes, and the normal suspension arms, suddenly competing with space with this gear drive.
Gears are NOT Friction Free. With that many layers of gears, the friction loss has to be significant. Also, how do you keep water and dirt out of those gears. And those gears are going to need grease fairly frequently. Other than that, what could possibly go wrong??? Oh, wear and gear lash when switching from acceleration to deceleration and back to Acceleration. Let’s see how it is working after several years.
Question for those smarter than me in the comments if someone can answer please! Does the HUB motor weighing more than the uniwheel gear setup change the center of gravity/safety parameters of an EV? I know the batteries weigh the most and are generally in the belly of the vehicle but does displacing the other heaviest components inside the HUB motors to the outer points of the vehicle make it safer or less safe than the uniwheel setup?
Each Aptera wheel motor will weigh under 50 lbs, and have far fewer parts. The center of gravity will be lowered slightly, compared to standard wheel/motor EVs.
cv joints work just fine why change what works? The inner joint can slide in/out internally it has large roller balls in it also, large angles are no problem. Friction doesn't change due to 'angulation' is that a word?
You COULD handle steering by having the wheel and motor on a pivot arm, but the rest of the front suspension would be tricky. and the brake system woukd be VERY tricky. imo A CV joint is needed ONLY for steering angle, and could have a rigidly mounted body, so it could be smaller but the brake system would still be VERY tricky
I'm not a big fan of the longevity of gears, oil and so on, although gears do make a elictric motor last a lifetime, so all in all either way as long as the hub is cost effective and easy to replace. I have seen many types of gears from automotive to industrial machinery, gears are picky and never last a lifetime, just think of a film of oil and metal teeth pushing and rubbing and spinning at high and low speeds with thousands of pounds of forces. I believe hub motors can be used with less issues because at high heat power can be reduced at the cost of speed only.
I love planetary gearing and cool engineering but this... the amount of precision needed will make this system relatively expensive and add further complexity. I want to see the efficiency of this setup, not just of the motor but of the cooling system and the wear life vs a hub motor. I'm dubious of this but it looks cool.
I'm at a loss to understand how all this design's complexity and inherent frictional losses is remotely close to better than a hub motor. Also, so many armchair engineers love pulling out the "unsprung mass" argument when talking about hub motors like its going to adversely affect the car's handling.. its an urban road car not a F1 car. get a grip.
Unsprung mass is more important on a road car for ride comfort as well as handling. Think of a pickup with that solid rear axle and huge tires and wheels, bouncing and jittering over every little bump, compared to a more lightweight, sophisticated suspension delicately and smoothly gliding over those bumps. You also lose traction when your tires bounce up and can't maintain smooth contact with the road, especially in emergency maneuvers.
@@jamesengland7461 I just dont buy it.. i know it affects handling but i still feel people are putting too much into it. Suspension damping can be tuned to minimize the effect as well. Plus they aint big heavy tires to begin with. I understand how unspring weight works.. but again, I feel like people are putting too much into it when it comes to a street car. Also, I have an F150 and the rear end does skip but only because it has suspension to handle 3000lbs in the back so its STIFF when nothing is in it. When my 2200lb camper is in the back it completely behaves itself.
If Y make the motor part of the steering so it move as a part of the axel and wheel, Y can steer the wheel. But there is another problem with that system, that is lubrications of the gears in the wheel, in a normal transmission the gear wheels runs in a oil bath and there is sealing, so the oil doesn't runs out, and dirt doesn’t come in…. That will be a week point, and the torque from the gears to the outer gear Thy needs to be spring loaded in order to be engaged all the time without jumping over ore slips, that is also a week point, and the movement of the axel up and down will ad stress to the bearings in the motor, and the runtime will be low unless Thy are big and beefy with lubricant flooding all the time. Remember the Tesla motor in model S early motor has to be replaced because of bearing failure, so There is a lot of engineering and Longevity testing before it will be a “Thing” that can replace old stuff, but Aptera in wheel motor will also need replacement of bearings over time like normal wheel bearings, all depending on the sizes and use of the environment Impact of the sealing of the bearings ….. greetings from Denmark 🇩🇰
How many parts does this add to the drive system? Each one is a source of drag and potential failure. Would saves some unsprung weight but at too high a cost.
The sheer complexity of putting that many extra gears in every single wheel seems prohibitive. i'm sure it'll work great when it's brand new, but that just seems like a recipe for expensive, regular maintenance.
It's like wearing work boots coated with a thick layer of mud versus wearing sandals- much more work to move them, much less agile and smooth over bumps.
Because of the added inertia of the heavier wheel assembly, it becomes harder for the suspension to keep the tire in contact with the road on bumpy surfaces. (A largish bump forces the wheel to rise, then it continues to "coast" upwards into the air even after it has cleared the obstacle.) This can result in imprecise steering and braking control on rough roads, and also a harsher ride.
Now this is a very worthy discussion of Aptera technology advances. The hub motors and the solar panels. Uni Wheel and Aptera Hub motors have same controls. For directional, it is controlled by the two CV joints. For differential speeds, it is controlled through software, each wheel has its own speed depending on the amp that sent to the motor. When you want to move to the right, the speeds of the left whees increased, the speeds of the right wheels decreased thru software. The two CV joints will take care of all differentials automatically. Like Aptera, Uni wheel has a motor for each wheel. You should talk more about the merits of solar panels on Aptera, which are made possible by the efficiency of Aptera. Solar panels efficiency is on the verge of step change improvements with Perovskite panels. The efficiency of Perovskite panels are approaching 40%. That would make Aptera a true solar car.
@@ApteraOwnersClub Yes I missed that one. Aptera controls the direction by two simpler joints a two ends of the control tie rods. One vertical and one horizontal. So Aptera saves two CV (constant velocity) joints versus Hyundai but in exchange for a little bit higher unsprung weight. Aptera might be a little more efficient by using less mechanical gears which will need regular maintenance like lubricants.
One inherent problem I see with the Uni wheel is that as you can see in the video @ 8:09 they use a booted flex CV joint to allow for steering angle and given the input RPM of the motor shaft to the sun gear designed wheel hub (roughly 9 to 1 ratio is what it looks like, which means input shaft RPM could easily be as high as 10,000 RPM) the rubber boot and CV joint is going to have to be redesigned to handle a much higher RPM than traditional CV joints. Also the input shaft to the wheel hub seal is going to be another problem area...with that high RPM input shaft exposed to the harsh elements of road debris and water a tradional oil or grease seal will not last very long.@@ApteraOwnersClub
@@rolandrauenhorst2002 The input RPM could be reduced by software because each wheel has its own motor. Just like Aptera torque steering control. Each wheel has its own speed via central computer. Being a fan of Aptera I still have to say torque steering is scary to me. From software to hardware interfaces like switches, PLC gates… many intervening pieces could fail silently. In Hyundai hybrid scheme, in case of complete failure of computer speed control, the two CV joints would still work automatically because it is purely mechanical. Just like a train wheels would take a corner or a turn automatically.
The input RPM is typically only reduced when traction becomes an issue or extreme turning angles. Torque steering is almost always only applied when traction is compromised either by slippery conditions like snow, ice or hydroplaning on water to keep the vehicle going in the direction directed by mechanically linked steering imputs. My point was that because Uni wheels planetary gear drive apears to be at least a 9 to 1 gear ratio the motors are going to be running around 10,000 RPM when crusing down the road. The typical CV jointed drive shaft runs at about 1,000 RPM and are not currently capable of running at such a high speed for various reasons...The rubber likely isn't strong enough to with stand the centrifical force and the grease also would likely be thrown outward due to the centrifical force, leaving the steel mechanism without sufficiant lubrication and it to would likely fail early and often. So the CV joint would have to be reengineered significantly to survive in this application also high RPM shaft seals are difficult to maintain under severely dirty conditions. @@Kukaboora
Looks like a nightmare to maintain. CV joints are fully enclosed and have decades of research and development, yet they are still one of the most likely failure points in the drive train. These things are never going to be mainstream.
No matter How Finely Machined, Every Mesh of a Gear has some Slack - (Lash). Add up every Joint between Motor and Wheel and You have a "Snatch" Load at every Thrust and Reversal. Requires Higher Torque Rating, Thus Heavier than needed. You will feel the "Jerk" at Thrust requirement. You have felt something like this if You have ridden a Motorcycle with a Slack Chain. It can be annoying. This effect will Gradually increase as the Gears Wear. Also, look at the Gears - Beveled Teeth. That develops Side Thrust at each Gear. Side Thrust = Friction Losses. They Bevelled the Teeth to make them Quieter, at cost of Friction Losses.
Too complex. You're introducing more parts and not really solving any problems. The efficiency gains will be negligible. If this were viable, F1 would have already tried it. I've been a mechanic since the '80s. It took a long time for CV joints to become reliable and inexpensive.
Owned only one Hyundai. One of the most costly per mile of the vehicles I have owned. Very disappointing still have a bad taste in my mouth over that one.
Yeah it all sounds great but if you watch the videos you learn that the wheel assembly with the motor inside of it weighs 120 lbs and that is unsprung weight that will pound the tire like crazy on the worse roads in this country that I drive on in Rhode Island.
Honestly this video was painful to watch, you clearly do not understand how CV joints work let alone they are merely one part of the drive shaft assembly. Throw in the splined shaft/slip joint and it is easy to account for any movement which requires extension of the drive shaft which means, the CV joint just worries about angular movement. There is no appreciable power loss here, a CV joint going bad can affect efficiency. Yes its a bit more complex than that and there are variations but the point is, all movement is accounted for, the Hyundai animation did not make that clear because they did not need that level of complexity to demonstrate their point Granted the real fun is Hyundai exaggerating the front motor to justify their technology. That arrangement looked more like a fuel cell stack or conventional motor rather than a typical electric motor and reduction gearing which can stack front to back or side to side. Tesla packs a very well sized frunk on their cars simply because the motor is space efficient. I don't agree with the Hyundai solution as it doubles the number of gear sets and in turn maintenance needs. I understand their desire to avoid hub motors as they are less efficient and why automakers avoid them. Why have two motors when one will work? Even Rivian avoided hub motors on their four motor design. Why? Unsprung mass which requires more advanced suspension tuning, the hub motor requires its own packaging to protect it from the elements, it is exposed to very much increased vibration and impacts, and finally having additional motors is not efficient. Finally in an accident it is far more likely to be damaged. Aptera trapped themselves into this by having the wheels outboard the vehicle body but even then they could have easily powered both wheels from one motor. Enclosing that drive shaft would have been simple.
And contrary to Aptera's performance goals for the vehicle. This is not being "trapped" but recognizing the optimum engineering solution for the purpose. It IS more efficient than adding the bearings and weight a drive shaft would require. If you have engineering experience, you would know that.
One of the takeaways from this video is that you really have to credit the ICE automotive industry for somehow making so many highly precise and complex assemblies affordable and reliable. I never gave CV joints much thought, but looking at the precision gears and bearings and housing and parts count inside of just one component and I am simply amazed that an ICE car can move more than 10 feet before something breaks down. Hub motors are much simpler than this uni-wheel concept and orders of magnitude simpler than an ICE car. I am looking forward to never returning to my local mechanic for repairs.
I've had to rehab more CV joints than anyone would want to, and I will be glad to see them go. BUT, they are absolutely brilliant works of complex geometry, especially considering that the early ones were designed with sliderules.
I've kept a couple of classic minis alive beyond their expected lives by decades. These Uni-Wheel contraptions are obviously a pull and replace item and with the complexity I'm guessing not cheap. They remind me of the pencil vs the ballpoint pen challenge of space.
Over 100/years of R&D will do that. Evs are still unrefined new tech by comparison and hub motors even less refined.
Let's hope our aptera radial hub motors have enough heat dissipation tech in it so that it doesn't overload.
@@DeSilver215 I designed and helped build a samples freezer for the ISS, among other high tech thermal projects. I have no basic worries regarding Aptera. They have an excellent solution with 3 separate cooling loops.
In my opinion, the simplicity of the in-wheel hub motor comes out clearly ahead. This is especially true in Aptera's case, because the light weight, super aerodynamic vehicle has less power demand, and this allows for an even lighter hub motor than would be typical. In-wheel hub motors are also direct drive, eliminating any additional gearing, knuckle joints, or drive shaft. Aptera and Elaphe are the clear winners in my mind.
I think a way premature assessment without any real data with both solutions not vetted in real world driving.
I came here to say just this. I’m watching this video and wondering why? We have hub motor technology so this feels like it is overly complex to an old problem.
It’s like they realized this problem 5 years ago and went into a room and just came out with the solution and now hub motors make their problem, and thus their solution, obsolete.
@@johnmalcom9159 That may be true, but analysis and common sense are what we have to go on until some driving history exists. Time to develop that real world data will provide actual answers... obviously.
You don't have to go on anything. Just weight until testing is complete. You need not decide on either c solution since neither is available in the market place. He vale of either is moot at this point.
I agree that hub motors are an elegant solution. I look forward to seeing them work in the real world. I think that there are real engineering challenges around unsprung weight and lack of flexibility with gear ratios. They do work pretty good on e-bikes though 😊
On the lighter side, I very much appreciate the CV joint video with the guy using his old underwear to clean the grease. Old skivvies always enhance the cinematic experience.
Steve, take a look at 4:41 and you can see the CV joint just inside the wheel that allows for steering rotation.
If you look it shows the CV thru it a lot . I didn't see it until you brough it up. Thanks
@@glen2880 Yep, I just grabbed a random spot showing it.
The need for the effective length of the driveshaft to change in traditional driveshaft design is accommodated by the design of the inner CV joint, which in addition to changing angle can also allow the shaft to move in and out.
YASA was purchased outright by Mercedes Benz, they make in-wheel motors. That tells me it is a viable product, with a future. Elaphe needs Aptera, and a vertical integration later would be a great thing for Aptera. Thanks number 26 Steve!
Two things they conveniently neglect to mention are how they would integrate mechanical brake components in the same space as the gear assembly, and how they would seal the Uniwheel where it moves around the input shaft. It looks like a very difficult challenge for keeping lubricant in and contaminants out.
One of the biggest innovations for early electric cars was going from a 3 pole to a 6 pole motor, which effectively doubled the torque and required one less stage of step down gearing.
Brushless motors from 2018 frequently had 36 poles on cinematic quadcopters. I have seen references to motors with 80 to 144 poles, which can deliver much higher torque and hence completely eliminate the need for mechanical gearing.
A perspective from a vehicle R&D engineer. First, Kudos to both Hyundhi and Apteera for taking the initiative and risk to engineer a potential upgrade to the conventional EV drive train design. Both are untried at this point. For both or either to be validly assessed as an improvement or "Best" solution it would require extensive real world driving under a plethora of driving conditions by a lot of real world customers in their own use cases over an extended time. A thought on the Uniwheel The Uniwheel has a lot of moving parts running under constant changing stress. Without the above vetting, it may prove to have low reliability with frequent faults that would cause a break down/failure. The Uniwheel reminds me of Mazda's innovative rotary engine. It works but never caught on. I wish them success as I support any improvement to make EVs work better and more efficiently.
Each wheel will also need gear oil bath. Pinion and ring gears wear out slowly if proper maintenance is performed. If maintenance is missed, pinion gears wear out quickly.
Looks like the UNIwheel has a joint on the outboard side of the shaft, which I think takes care of steering angle. Looks like it not just goes up/down in stroke but also fore/aft too so shaft can same lenght and straight.
It seems to me that they could have the electric motor rotate as the wheel turns, with the pivot point of the motor's rotation being in the center of the arc. With the uni-wheel handling the other translational motions. Hyundai would never release or announce their Uni-wheel if they had not first worked out this fundamental steering functionality. But I totally agree with you that the in-wheel motor has the advantage of more simplicity and efficiency, while sharing the uni-wheel's advantages over conventional CV joints and transmissions. With the one downside being a little more unsprung weight for in-wheel motors.
Yes, after reading your comment, I can see that this is reflected in the animations.
There is a mechanical advantage to the Uni Wheel over a hub motor design in that the motor can operate at higher speeds and therefore produce the same torque with smaller, lighter motors. The disadvantage comes with complexity of the system . In the eBike world, mid-drive motors running at higher speeds and torque have supplanted rear wheel hub motors because they are so much lighter.
eBikes may not be the best comparison as the drive system is such a large fraction of the total vehicle mass. Trading off a bit of mass may not be as big a deal for cars. Nevertheless if elaphe motors are close to 60kg, that does seem rather heavy. I worry about loads on the suspension system.
On the flip side, how awesome would it be if you could just replace the rear wheel in 5 years and get an entirely new hyper advanced axial flux drive system (assuming a rear wheel drive model)?
as for turning....the motor turns (pivots) with the wheel...at least the animation shows that. 10:31
Hub motor is limited on speed and torque due to space allowance; whereas the uniwheel could gear torque out of a smaller motor to lower cost of the motor. For applications requiring more torque could displace a much larger motor than a hub motor. Another benefit is motor protection; clearly having the motor tucked away on the frame and not bouncing around hitting pot holes and children will increase the longevity of it. Aptera Max speed is 105mph, I believe. With gearing in the hub, the motor would be allowed to run at higher RPMs. I absolutely love the hub motor for the Aptera; it’s a perfect match. For larger vehicles and race cars, the uniwheel might be a better solution. Btw, a small CV in the format will handle flexing for steering, they showed side to side motion in their illustration with a cv coupler. I’m keenly interested how the uniwheel handles regenerative braking.
105 MPH is fast enough unless you want to Track Race your Aptera. 0-60 in 4 seconds is fast enough unless you enjoy self-induced whiplash. Aptera and Rousch. Engineering are working hard to minimize the downside of the extra unsprung weight. Does anyone know how much the Aptera optimized hub motors will weigh vs the United States-hub?
Steve, look at 10:28 in the video and you'll see they do show a steering rack connected to the wheels but no close up of the connection. I suspect the steering rack and connections are just leftover parts of the centered power source render because the inset starting at 10:36 shows the steered wheels turning on the standard central power source but not on the uni-wheels. Perhaps they plan on using torque vectoring for steering purposes, but I don't see that being very efficient. As for their suggestion starting at 11:23 about the uni-wheel working in ANY form of transportation, I thought of the following forms: boats and ships, rail, and aircraft. They could have said "wheeled form of transportation" (though rail uses wheels).
For HEAVY vehicles requiring larger/heavier hub motors, the unsprung weight becomes a problem. Aptera manages b/c it’s light and can use lighter/smaller hub motors. There’s bound to be some unsprung weight penalty, but it keeps the front body volume minimal where it needs to be narrowing down for aero.
The inner joint is the one that allows the movement. The deeper the inner joint, the more movement the axle has in and out
I love your video and is part of why I've reserved one. I was wondering if you could do a comparison video between Aptera and the solar charging Prius Prime? I think you'd you do a great job comparing the two.
The key advantage of this design is in high performance, high speed vehicles. You mentioned the unstrung mass but the bigger thing is that externalizing it allows higher performance motors and potentially a transmission to allow far higher top speeds. If Hyundai licenses out the technology I could see something like an updated model s plaid or roadster using it since the compromise in top speed for a hub motor isn't acceptable for them. As to steering I think a simpler mechanism than a CV can be used since it only needs a single rotational axis.
That sounds like it add up to mre mechanical losses of energy, require maintenance, and potential points of failure.
If I could chose either option on the same vehicle I would opt for the wheel motors.
@@garywozniak7742 Not saying hub motors are bad but they will never be the absolute peak performance option. They are fast enough (even detuned for efficiency) that Aptera can match the AVERAGE Dodge Viper or Porsche in 0-60.
@@ccibinel I worked across the street from Tesla in 2008. In 2021 I had a ride in an Aptera prototype that accelerated far faster than those Roadsters did at the time (without breaking a transmission).
You had a big question about the steering with you any wheel I think what they do is the motor has to move sideways and pivot around the wheels pivot point
Thanks for the focus Steve. Too complicated for me. How many times I've fought the CV and, with enough money, won but not a fight I look forward to. The advantage of the UniWheel is one power source. Our Aptera has at least two. I wonder what the difference in cost would be? I also noticed they didn't mention the inside universal system nor the weight of this double axle assembly but our in-wheel approach isn't the battle this innovation is fighting.
At 4:20 you talk about upper and lower control arms. This configuration requires no upper control arm. The strut pictured controls the upper spindle lateral and longitudinal positioning and is a point of rotation on its long axis. The lower control arm will have its ball joint in line with the upper strut. Midway between the two, on the same axis, is the CV joint in this image to allow for steering.
So you are adding 11 gears with bearings and shafts and a ring gear. You see the small diameter of those gears. They will be screaming at high speeds. How do you keep them lubricated? I think it is a brilliant design for a slower moving vehicle, so you could have enough oil or grease in there to keep the heat down. With four of these you would be adding about 160 parts to the vehicle. I don't see that as a design improvement. Funny that uni usually means one.
I could see how it'd turn if it were on a motorcycle or an electric unicycle. If they could design this same concept in a 360° sphere/tire and utilize it on an electronic unicycle with off road capabilities they'd have a unique fun transportation device. The foot controls would be weird to get used to but the ability to strafe would be unique.
I wonder about longevity. With that many gear surfaces there would have to be lubrication, so will it be a sealed gearbox, but how do you seal a movable input shaft?
I would think having all those gear interactions would build up the gear lash and generate more heat.
NEVS in hub drive removes the need for any drive shafts, the only thing to change in that set up to use an axial flow electric motor that is even smaller and lighter.
It allows for a transmission where a hub motor doesn't. It would also work for ICE cars. It appears to have a cv joint for turning that is smaller and normally straight while going down the highway.
I'd argue that having a transmission is not an advantage.
Lighter unsprung weight per wheel end vs Elaphe hub! Possibly for a Mk II Aptera.
Far more frictional losses due to the more complex gearing.
At 4:00 when they discuss how it works, I see a lot of moving parts that need maintenance. Then the animation of the up and down motion and then asked to myself, what about the wheel moving forward and backwards?
That assembly better be made from a strong lightweight material, otherwise it'll take a beating.
I like the concept although as you mentioned in your video more points of failure in this new Hyundai motor. I would have all the parts stamped out in Carbon fiber all the bushings and gear armature Carbon Fiber. Reduce weight increase strength. Basically your wheels are the Car so no expense should be negated in this technology. Thanks for the video.
Thanks Steve for doing this video!
Hyundai has another video showing their torque vectoring and 90 degree rotation of each wheel, allowing for going 90 degree change of direction after a full stand still position.
Do you know why they don't just try hub motors?
It requires CV joints for steering (which they aren't showing in their presentation)
Hyundai's visuals show the uniwheel driving the front of the car. I'm guessing they've traveled the problem of steering movement at the wheels. But it's a good question how they do it.
Some problems I can see with the uniwheel, compared to a hubmotor: the friction of the gearset, lubrication and sealing the gearset from the elements, limits to suspension travel.
The dynamic face seals sound like a nightmare issue.
Animation seemed to show the motor and shaft moving with the steering. More complications.
The video for the uni-wheel still shows a bellows on the outside joint. I assume there is still an outer cv joint for steering.
im confused why a steering rod would need a cv joint. Do you mean a ball joint?
@@Jojo-o6o6w The hub needs a pivot to allow for steering because the motor is inboard an fixed to the subframe. That’s one of the jobs a CV joint does in a conventional FWD car and that’s what I am referring to.
@@juancarrera5524 sory i dont get it.. i have a front wheel drive truck and the steering rods have ball joints at the end of them, the CV joints are in the drive axles.
You would likely have to pivot the whole motor with the wheel for steering.
The inherited problems with inwheel motors are:
* Increased inertia/unsprung weight
* In order to decrease unsprung weight you might use gears with smaller motor, but then you increase complexity of the system substantially
* If you go without gears, more magnets are needed to achieve desired torque values (aptera's approach), and there is more weight
* Protection of the motor against shocks, dirt, water and salt ingress is still unproven technology (no oem uses it for passanger vehicles yet)
* Power and cooling cables need to be supplied to the wheels, which may experience fast and large movements relative to the vehicle... how reliable can this work is yet to be proven
* Often praised "increased efficiency" is debatable, it is probably under 5% compared to conventional drives
I must admit that I never welcomed apteras decision to go with inwheel motors. Why opt for unproven technology that has at least as many potential drawback as advantages, for very modest efficiency gains? Why increase the risk of failing their primary concept at the market, to which it wouldn't contribute much anyway?
This hyundai approach looks it might work well combined with the axial motor type (which have higher power density then elaphe radial motor)...but of course it remains to be seen how well they resolved the protection of those gears.
The Rivian R1T and R1S both use in wheel motors.
@@garywozniak7742 I think they use one motor for each wheel, but they are not inside a wheel. Rather the motors are attached to wheels by (a very short) shaft (see en.wikipedia.org/wiki/Individual_wheel_drive).
Showing the complicated drivetrain is a hybrid car but the simplified vehicle is a true electric vehicle. An EV doesn’t have an internal combustion engine.
like the narater says there are more partes that add weight and the moters are close to the driver
The system appears to be more fragile than any of the hub motors or traditional drivetrains. It would be interesting to see in actual use
Perhaps the joint for steering is on the motor side.
I see these being used more for higher power vehicles, hub in the front, significantly larger motors in the back
Could make an excellent system for semis
This is kind of a compromise between a CV joint vice an in-wheel motors as you realized. This does allow a centralized motor rather than 2 or 3 motors in the Aptera. So if Elaph Motors are more efficient but does require electrical power connections to it so it is a valid potential tradeoff. There are ways to allow rotations at the hub.
2 or 3 motors would simply be each smaller than 1 motor, and that 1 motor would need driveshafts to each powered wheel, negating every benefit.
@@jamesengland7461 Yes, but it is still a tradeoff. I think I know the result of the tradeoff, as do you. But if you come from a centralized motor paradigm, the uni-wheel concept is progress.
The thousands of contact points in those gears could be problematic as they wear over time. And as small as those gear teeth are, it wouldn't take much wear before they are out of tolerance. The assembly would have to be sealed extremely well since it operates in the vehicle's dirtiest environment, at the road. Maybe Hyundai is thinking this would give their service departments something to do on a regular basis, to make up for lower service for EVs.
Yeah for this to be used with the front wheels it'd need the motors on a slider system.
At 10:28 th-cam.com/video/lGiWlf2MSX4/w-d-xo.html It looks like the front wheels steer a little bit and it looks to me like the electric motors move with them to keep a straight connection to the wheels.
I can understand how a hub motor is so much better, why aren't others using it?
Good question more so when you note hub motors were used in EVs in the early 1900s. Hub motors are from the electric trolley systems
At about 10:30 in the video they move the electric motor slightly when the wheel turns. I believe that's how they plan to steer.
Not sure if this has been addressed already, but perhaps you can steer left by manipulating the speed of the left vs right wheels: slow left wheel + fast right wheels = left turn.
Just my thoughts from someone who has no knowledge of cars/gears/mechanics/etc. I'm guessing that's it's probably more complicated than that.
Each time power is passed through a gear there is friction loss. In each uniwheel there are ten gear tooth contact points of power transfer through which power is passed and a bearing on both ends of each gear wheel support shaft. Rube Goldberg couldn't have made this more complicated. In the diagram/picture at 6:50 I count 31 points of wear on each wheel plus any additional bearings to allow steering. In an all wheel drive vehicle this presents at least 124, plus any I missed, plus any steering required drive bearings, points of failure, as opposed to Aptera all wheel drive six total drive bearings/points of failure. That is a wear point trade for unsprung weight I am willing to accept. Aptera looks better and better.
I would not be so sure on a weight penalty in all cases. That ring gear will need to be pretty robust and there will need to be lubrication in the gear compartment. 11 hardened gears and associated linkages and shafts is not going to be light weight in my experience. Unless you do some expensive manufacturing for hollow shafts and optimized gear structures to reduce the weight.
Given that the drive axle is still there, with pivoting and telescoping features, and the transmission/gear reduction is just moved inside the wheel, nothing has been accomplished here except to move more sprung weight to the wheels. There's still the matter of hub bearings, lug nuts, brakes, and the normal suspension arms, suddenly competing with space with this gear drive.
Gears are NOT Friction Free. With that many layers of gears, the friction loss has to be significant. Also, how do you keep water and dirt out of those gears. And those gears are going to need grease fairly frequently. Other than that, what could possibly go wrong??? Oh, wear and gear lash when switching from acceleration to deceleration and back to Acceleration. Let’s see how it is working after several years.
Question for those smarter than me in the comments if someone can answer please!
Does the HUB motor weighing more than the uniwheel gear setup change the center of gravity/safety parameters of an EV?
I know the batteries weigh the most and are generally in the belly of the vehicle but does displacing the other heaviest components inside the HUB motors to the outer points of the vehicle make it safer or less safe than the uniwheel setup?
Each Aptera wheel motor will weigh under 50 lbs, and have far fewer parts. The center of gravity will be lowered slightly, compared to standard wheel/motor EVs.
cv joints work just fine why change what works? The inner joint can slide in/out internally it has large roller balls in it also, large angles are no problem. Friction doesn't change due to 'angulation' is that a word?
You COULD handle steering by having the wheel and motor on a pivot arm, but the rest of the front suspension would be tricky. and the brake system woukd be VERY tricky. imo A CV joint is needed ONLY for steering angle, and could have a rigidly mounted body, so it could be smaller but the brake system would still be VERY tricky
Wouldnt you use the motors to do the braking thru the gears?
ya, they suspiciously neglected the explain how power will be transmitted 'efficiently' when the wheel is turned.
I'm not a big fan of the longevity of gears, oil and so on, although gears do make a elictric motor last a lifetime, so all in all either way as long as the hub is cost effective and easy to replace. I have seen many types of gears from automotive to industrial machinery, gears are picky and never last a lifetime, just think of a film of oil and metal teeth pushing and rubbing and spinning at high and low speeds with thousands of pounds of forces. I believe hub motors can be used with less issues because at high heat power can be reduced at the cost of speed only.
I love planetary gearing and cool engineering but this... the amount of precision needed will make this system relatively expensive and add further complexity. I want to see the efficiency of this setup, not just of the motor but of the cooling system and the wear life vs a hub motor. I'm dubious of this but it looks cool.
I'm at a loss to understand how all this design's complexity and inherent frictional losses is remotely close to better than a hub motor. Also, so many armchair engineers love pulling out the "unsprung mass" argument when talking about hub motors like its going to adversely affect the car's handling.. its an urban road car not a F1 car. get a grip.
Unsprung mass is more important on a road car for ride comfort as well as handling. Think of a pickup with that solid rear axle and huge tires and wheels, bouncing and jittering over every little bump, compared to a more lightweight, sophisticated suspension delicately and smoothly gliding over those bumps. You also lose traction when your tires bounce up and can't maintain smooth contact with the road, especially in emergency maneuvers.
@jamesengland7461 yet Aptera seems to have implemented a design where they work well. Based on the Beta prototype Moose Test and test drive results.
@@jamesengland7461 I just dont buy it.. i know it affects handling but i still feel people are putting too much into it. Suspension damping can be tuned to minimize the effect as well. Plus they aint big heavy tires to begin with. I understand how unspring weight works.. but again, I feel like people are putting too much into it when it comes to a street car. Also, I have an F150 and the rear end does skip but only because it has suspension to handle 3000lbs in the back so its STIFF when nothing is in it. When my 2200lb camper is in the back it completely behaves itself.
@@bobhellman8676 its a truck camper not a trailer :) its HEAVY
If Y make the motor part of the steering so it move as a part of the axel and wheel, Y can steer the wheel.
But there is another problem with that system, that is lubrications of the gears in the wheel, in a normal transmission the gear wheels runs in a oil bath and there is sealing, so the oil doesn't runs out, and dirt doesn’t come in…. That will be a week point, and the torque from the gears to the outer gear Thy needs to be spring loaded in order to be engaged all the time without jumping over ore slips, that is also a week point, and the movement of the axel up and down will ad stress to the bearings in the motor, and the runtime will be low unless Thy are big and beefy with lubricant flooding all the time. Remember the Tesla motor in model S early motor has to be replaced because of bearing failure, so There is a lot of engineering and Longevity testing before it will be a “Thing” that can replace old stuff, but Aptera in wheel motor will also need replacement of bearings over time like normal wheel bearings, all depending on the sizes and use of the environment Impact of the sealing of the bearings ….. greetings from Denmark 🇩🇰
How many parts does this add to the drive system? Each one is a source of drag and potential failure. Would saves some unsprung weight but at too high a cost.
Hub Motors >
The sheer complexity of putting that many extra gears in every single wheel seems prohibitive. i'm sure it'll work great when it's brand new, but that just seems like a recipe for expensive, regular maintenance.
exactly.. way too much going on for VERY little benefit.
I think Aptera is better off sticking with its hub motors.
Please explain the disadvantage of more unsprung weight?
It's like wearing work boots coated with a thick layer of mud versus wearing sandals- much more work to move them, much less agile and smooth over bumps.
Because of the added inertia of the heavier wheel assembly, it becomes harder for the suspension to keep the tire in contact with the road on bumpy surfaces. (A largish bump forces the wheel to rise, then it continues to "coast" upwards into the air even after it has cleared the obstacle.) This can result in imprecise steering and braking control on rough roads, and also a harsher ride.
@@robertkirchner7981 now that makes sense thanks!
Why is unsprung weight a bad thing?
It adds inertia to the suspension movement. However, the amount is within reasonable limits, even though it is a disadvantage taken by itself.
Now this is a very worthy discussion of Aptera technology advances. The hub motors and the solar panels.
Uni Wheel and Aptera Hub motors have same controls. For directional, it is controlled by the two CV joints. For differential speeds, it is controlled through software, each wheel has its own speed depending on the amp that sent to the motor.
When you want to move to the right, the speeds of the left whees increased, the speeds of the right wheels decreased thru software. The two CV joints will take care of all differentials automatically.
Like Aptera, Uni wheel has a motor for each wheel.
You should talk more about the merits of solar panels on Aptera, which are made possible by the efficiency of Aptera.
Solar panels efficiency is on the verge of step change improvements with Perovskite panels. The efficiency of Perovskite panels are approaching 40%. That would make Aptera a true solar car.
There are no cv joints on the Aptera hub motors
@@ApteraOwnersClub
Yes I missed that one. Aptera controls the direction by two simpler joints a two ends of the control tie rods. One vertical and one horizontal.
So Aptera saves two CV (constant velocity) joints versus Hyundai but in exchange for a little bit higher unsprung weight.
Aptera might be a little more efficient by using less mechanical gears which will need regular maintenance like lubricants.
One inherent problem I see with the Uni wheel is that as you can see in the video @ 8:09 they use a booted flex CV joint to allow for steering angle and given the input RPM of the motor shaft to the sun gear designed wheel hub (roughly 9 to 1 ratio is what it looks like, which means input shaft RPM could easily be as high as 10,000 RPM) the rubber boot and CV joint is going to have to be redesigned to handle a much higher RPM than traditional CV joints. Also the input shaft to the wheel hub seal is going to be another problem area...with that high RPM input shaft exposed to the harsh elements of road debris and water a tradional oil or grease seal will not last very long.@@ApteraOwnersClub
@@rolandrauenhorst2002
The input RPM could be reduced by software because each wheel has its own motor.
Just like Aptera torque steering control. Each wheel has its own speed via central computer.
Being a fan of Aptera I still have to say torque steering is scary to me. From software to hardware interfaces like switches, PLC gates… many intervening pieces could fail silently.
In Hyundai hybrid scheme, in case of complete failure of computer speed control, the two CV joints would still work automatically because it is purely mechanical. Just like a train wheels would take a corner or a turn automatically.
The input RPM is typically only reduced when traction becomes an issue or extreme turning angles. Torque steering is almost always only applied when traction is compromised either by slippery conditions like snow, ice or hydroplaning on water to keep the vehicle going in the direction directed by mechanically linked steering imputs. My point was that because Uni wheels planetary gear drive apears to be at least a 9 to 1 gear ratio the motors are going to be running around 10,000 RPM when crusing down the road. The typical CV jointed drive shaft runs at about 1,000 RPM and are not currently capable of running at such a high speed for various reasons...The rubber likely isn't strong enough to with stand the centrifical force and the grease also would likely be thrown outward due to the centrifical force, leaving the steel mechanism without sufficiant lubrication and it to would likely fail early and often. So the CV joint would have to be reengineered significantly to survive in this application also high RPM shaft seals are difficult to maintain under severely dirty conditions. @@Kukaboora
Looks like a nightmare to maintain. CV joints are fully enclosed and have decades of research and development, yet they are still one of the most likely failure points in the drive train. These things are never going to be mainstream.
Marketing Malarkey
The uniwheel looks like it will have a Hugh problem with water and dirt getting in.
And Snow & Ice.
This sounds like something for use in electric unicycles lol
Seems like all the small gears take a lot of stress going over rough roads and hitting pot holes.
you can see the steering concept in 10:37. It seems linke they rotate the enitre motor.
No matter How Finely Machined, Every Mesh of a Gear has some Slack - (Lash). Add up every Joint between Motor and Wheel and You have a "Snatch" Load at every Thrust and Reversal. Requires Higher Torque Rating, Thus Heavier than needed. You will feel the "Jerk" at Thrust requirement. You have felt something like this if You have ridden a Motorcycle with a Slack Chain. It can be annoying. This effect will Gradually increase as the Gears Wear. Also, look at the Gears - Beveled Teeth. That develops Side Thrust at each Gear. Side Thrust = Friction Losses. They Bevelled the Teeth to make them Quieter, at cost of Friction Losses.
The best part to do a job is no part if you can or the least ness. for completion of the task. So say's Elon Musk.
For turning, the motor can also turn.
That is an awful lot of parts to fail. Also wear.This over complicates the drive system.
Too complex. You're introducing more parts and not really solving any problems. The efficiency gains will be negligible. If this were viable, F1 would have already tried it. I've been a mechanic since the '80s. It took a long time for CV joints to become reliable and inexpensive.
Those Uniwheel gears... well, the whole apparatus really, looks pretty fragile.
Hyundai and reliable power trains don't fit in the same sentence.
Owned only one Hyundai. One of the most costly per mile of the vehicles I have owned. Very disappointing still have a bad taste in my mouth over that one.
Why do you need to trash someone for you to be better?
Hyundai is not a person. He's just giving his opinion on their reliability@@Kukaboora
For ICE, I’d avoid a Hyundai like the plague. As for their EV reliability, only time will tell.
Yeah it all sounds great but if you watch the videos you learn that the wheel assembly with the motor inside of it weighs 120 lbs and that is unsprung weight that will pound the tire like crazy on the worse roads in this country that I drive on in Rhode Island.
Honestly this video was painful to watch, you clearly do not understand how CV joints work let alone they are merely one part of the drive shaft assembly. Throw in the splined shaft/slip joint and it is easy to account for any movement which requires extension of the drive shaft which means, the CV joint just worries about angular movement. There is no appreciable power loss here, a CV joint going bad can affect efficiency. Yes its a bit more complex than that and there are variations but the point is, all movement is accounted for, the Hyundai animation did not make that clear because they did not need that level of complexity to demonstrate their point
Granted the real fun is Hyundai exaggerating the front motor to justify their technology. That arrangement looked more like a fuel cell stack or conventional motor rather than a typical electric motor and reduction gearing which can stack front to back or side to side. Tesla packs a very well sized frunk on their cars simply because the motor is space efficient.
I don't agree with the Hyundai solution as it doubles the number of gear sets and in turn maintenance needs. I understand their desire to avoid hub motors as they are less efficient and why automakers avoid them. Why have two motors when one will work? Even Rivian avoided hub motors on their four motor design. Why? Unsprung mass which requires more advanced suspension tuning, the hub motor requires its own packaging to protect it from the elements, it is exposed to very much increased vibration and impacts, and finally having additional motors is not efficient. Finally in an accident it is far more likely to be damaged. Aptera trapped themselves into this by having the wheels outboard the vehicle body but even then they could have easily powered both wheels from one motor. Enclosing that drive shaft would have been simple.
And contrary to Aptera's performance goals for the vehicle. This is not being "trapped" but recognizing the optimum engineering solution for the purpose.
It IS more efficient than adding the bearings and weight a drive shaft would require. If you have engineering experience, you would know that.
@@shrimptopian3392 Based on? Their Mosaic score (used to rate the financial health of private companies) has gone UP by 20 points the last 30 days.
No! Next question.