[HN Gopher] Mechanics invent an axle that can achieve steering a... ___________________________________________________________________ Mechanics invent an axle that can achieve steering angles of up to 80 degrees Author : tnorthcutt Score : 192 points Date : 2022-07-25 13:49 UTC (9 hours ago) (HTM) web link (interestingengineering.com) (TXT) w3m dump (interestingengineering.com) | gene-h wrote: | Why stop at 80 degrees? With electric drive it's possible to do | 360 degree steering[0]. | | [0]https://www.proteanelectric.com/technology/#protean360plus | ninju wrote: | Eye-catching graphics and cool soundtrack | | What about a real product? | znpy wrote: | I couldn't care less about in-car enterntainment systems or | heated seats. | | But this... I want this. | _trampeltier wrote: | Solution from 1927 | | https://m.youtube.com/watch?v=QilY00dCof8 | | This was even 90 degrees | jacquesm wrote: | Nice find, I never knew that such a thing was done in that way. | You really don't want to think about what would happen if that | mechanism ever triggered while driving :) | | Also, I wonder how they kept the alignment properly, that is a | pretty small tolerance affair unless you want to go through a | new set every 1000 km or so. | selimnairb wrote: | Now people who grew up in suburbs will have to find a new excuse | for not being able to parallel park. | gnicholas wrote: | > _Do you have trouble with parallel parking?_ | | Many times when I see people having difficulty parallel parking, | it's because they don't know when to turn and how much. They end | up parked 3 feet from the curb because of their timing errors. | | Something like this would make it easier to park in spaces, but | it won't fix of not knowing the steps to parallel park. | a_t48 wrote: | I was better at parallel parking before I got a new car. Super | afraid about curb rash. :( | gnicholas wrote: | I rarely use my car's self-parking feature, largely because | it forces me to pull forward way too far before it will take | over. | | But I've started activating the self-parking mode while I | park manually, since it forces the backup camera to be turned | on at all times. Otherwise it's only on when I'm in reverse. | jacquesm wrote: | Another car that will do _very_ tight turns: | | https://www.youtube.com/watch?v=S1UaC51OSPw | Terr_ wrote: | As much as I love these concepts, there's a hidden externality to | consider: If one car only needs extremely small margins to park, | it's possible for conventional cars ahead or behind to lose too | much of their normally-expected larger buffer space, and be | unable to (easily) leave. | wolrah wrote: | > If one car only needs extremely small margins to park, it's | possible for conventional cars ahead or behind to lose too much | of their normally-expected larger buffer space, and be unable | to (easily) leave. | | Doesn't the same apply already with large low-maneuverability | vehicles versus subcompacts? | | If there's a Ford Excursion or Chevy Suburban overhanging a | parallel parking space in to the space in front of it, there's | a good chance my Fiesta still fits just fine. If I park there, | that's probably going to make it harder for them to leave. | | I know in a lot of the world the American city style of | parallel parking with defined spaces isn't a thing, you just | park along the curb wherever your vehicle fits, but still this | situation already exists. Smart cars, those little one seat | city runabouts, motorcycles, etc. will fill the tiniest gaps | given the opportunity and people still get by. | wkearney99 wrote: | That was my first impression as well, seeing how close the | vehicles ended up. | anentropic wrote: | Looks great! | | Couldn't help noticing the video appears to show the demo car | also has 4WS with rear wheels also steering | | ZF's own page about this has a bunch more info | https://www.zf.com/products/en/cars/stories/maneuverable.htm... | | Their page also contradicts the Interesting Engineering where it | said: | | "The system further requires an unusually large amount of space | in the wheel wells to get that kind of angle, one that can only | be achieved in front-wheel drive vehicles." | | The ZF page states the opposite: | | "EasyTurn is suitable for vehicles with rear-wheel drive, the | usual setup in electric cars. And it is ideally suited for volume | segments because the MacPherson axle is compatible with around 80 | percent of today's common platforms" | robin_reala wrote: | Yeah, that struck me as well. The demo video uses an i3 which, | unless they've done some serious reengineering, is a RWD | vehicle. | jcampbell1 wrote: | This only works for rear wheel drive. The author is terribly | confused. To achieve these turns, the torque is applied on | the outer rear wheel by braking the inside rear wheel. | darksaints wrote: | It's gotta be a typo. Front wheel drive gives you the opposite | of a lot of space in the wheel wells. | UniverseHacker wrote: | I agree this must be a typo! The demo car in the video (BMW | i3) is a rear wheel drive car. | | Given that, this whole thing doesn't make any sense to me as | a supposed advance. RWD cars have always had tighter turning | raidii. Many of them actually have a stop to keep you from | turning the wheel 90 degrees such that the tires push instead | of roll. I remember adjusting an early 70s Volvo so the front | wheel could turn almost 90 degrees just as an experiment, and | doing this adjustment was trivial. | twawaaay wrote: | Well, FWD cars will always have a potential for tighter | turning radius. | | RWD car is essentially pushing on a wheel that is almost | perpendicular -- not very helpful, a lot of force needed to | start the car rolling, potential to damage the wheel. As | you get closer to 90 degrees the force needed becomes | higher than available traction and the entire thing stops | steering at all. | | FWD can be thought as "pulling" the car by the front of it, | the wheels can be in any position as long as we know how to | transfer power. | ryukoposting wrote: | Sure, it's true that "FWD cars will always have a | potential for tighter turning radius." In practice, | that's not the case for conventional front-engine | layouts. | | Most RWD cars mount their engines longitudinally, so the | transmission sticks out the back of the engine. This | means there isn't a whole lot of "stuff" sticking out to | the left and right of the engine. That means more room | for wheel articulation. | | One problem with FWD is space. Since the engine is | usually mounted transversely, the transmission has to go | under/beside the engine, taking up space that would | otherwise be usable for larger suspension components / | wheel articulation. | | The other problem with FWD is, as you mention, power | transfer. It would be extremely difficult to design a | shaft that could transfer power to a wheel that | articulates up to 80 degrees. Keep in mind that such a | shaft must snake its way through suspension components, | too. | | I suspect that the BMW i3 was featured in the video for a | lot of reasons: | | 1) It's RWD, which leaves room for extreme wheel | articulation. | | 2) It's electric, so there's less stuff up front in the | first place. | | 3) The i3's tires are super skinny, meaning less | resistance on those super tight turns. | bbarn wrote: | > Couldn't help noticing the video appears to show the demo car | also has 4WS with rear wheels also steering | | First thing I noticed as well. I would imagine it's also | possible without it, but you'd likely be losing traction on the | rear inside wheel? At slow speeds some cars already do this | anyway, even with the differential helping minimize it. | photoGrant wrote: | You use a lovely thing called a haladex | jacquesm wrote: | Haldex? | jjtheblunt wrote: | or torsen | throwaway0a5e wrote: | Considering a) ze German penchant for interesting control | linkages and b) the lack of an 80degree CV shaft shown in the | demo video I'm assuming this is a RWD thing. | | If they could pull of an 80deg CV joint, hell even a 60deg one, | at a decent price/performance point that would be the real | money maker here. Every fork lift made in the last century can | turn the wheels near 90, being able to transmit the power there | (like you need in a FWD application) is the hard part. | | Furthermore, work trucks and vans need this kind of stuff a lot | more than compact cars do. A tiny car already turns good enough | to be not a pain point in practice, the opposite really. People | are already highly satisfied with them so making it turn better | is just dick measuring. Taking a van that turns bad and making | it turn good is a competitive advantage. | jabroni_salad wrote: | A lot of commercial operations (including usps actually) take | a 'just dont ever reverse anytime anywhere' approach with | their drivers to reduce accidents. I could definitely see | this being hugely popular on work trucks and vans. | 0xbadcafebee wrote: | > A tiny car already turns good. | | This device would gain us 1-2 more cars per parallel parked | city block (if it took off). You simply can't get out of a | parallel parked space without extra room due to steering | angle. | prmoustache wrote: | It is more about how much patience do you have than | steering angle. | ActorNightly wrote: | The issue is that there is a lot of other things that you | have to consider when designing linkages. You have to make | sure the system is directionally stable, and works with | suspension. On forklifts, you don't really need to design for | that. | hnov wrote: | Maybe the thing to solve this will be individual electric | motors that are mounted to subframe as to not add unsprung | mass but articulate with the wheel somehow. Or more | realistically instead of huge angle on undriven wheels, a bit | of an angle on all wheels. It's been done for a while, in the | 90s on Japanese sports cars and now German luxo barges. | SigmundA wrote: | Something like Ree [1] drives will probably be the future, | minimizing unsprung while moving the drivetrain out to the | wheels. I could see a top mounted motor driving a splined | shaft that is also the kingpin with a sliding pinion | driving wheel and you would have full 360 ability just have | to keep friction down on the sliding pinion. Basically | sliding pillar suspension with the pillar also being the | driveshaft. | | Or just rotate the whole drive with suspension unit, just | needs a much larger wheel well. | | 1. https://ree.auto/technology/ | baybal2 wrote: | SigmundA wrote: | Or a hub drive electric. | neuralRiot wrote: | >being able to transmit the power there (like you need in a | FWD application) is the hard part. | | I don't think that's very hard as forklifts or any other | material- moving equipment don't have the speed factor | constraints so they can use wheel mounted hydraulic or | electric motors. | bob1029 wrote: | If you want to see some even more insane steering angles, check | out drift cars. They've been doing this for a while now. | | Even discounting the parking & u-turn use cases, the amount of | extra control you get at the extremes with more steering angle | can be pretty remarkable. | | It took me a long time to figure out why so many cars in downtown | Houston had super fucked up tire arrangements (extreme camber, | sticking out really far, etc). Apparently drifting setups are | kind of a big deal in the car community now. Makes a lot more | sense once you understand the engineering and use cases. | Kirby64 wrote: | Donut Media (big YouTube channel) has a series of videos that | have been uploaded quite recently showing the installation of | some of the drift car parts needed to do this super high | steering angle gear. They do drifting after the installs and | you can see how big an impact it has on maneuverability. | | See: https://www.youtube.com/watch?v=L73giZ75jTU | replygirl wrote: | most knuckles on drift builds are between 60 and 70 degrees-- | putting 80 on a RWD electric car is just a great way for the | average driver to spin when they try to avoid a collision | mwint wrote: | Huh, I always thought they did that because someone | (mistakenly) thought it looked cool. The extreme camber | actually does help with a measurable aspect of handling? | jacquesm wrote: | In extreme conditions, yes. But in normal conditions and if | you care about tire wear it is a net negative. | tristor wrote: | There are two completely disparate car communities that use | camber. | | 1. People who need negative camber to support high traction | while drifting or in tight turns on a race track. (this is | the minority unfortunately) | | 2. Stance kids who think it looks cool and put "most locally | hated" stickers on their car and post about it constantly on | TikTok. (this is the majority, unfortunately). | | There are very few track-driven vehicles running more than -6 | degrees of camber in the front, meanwhile it is commonplace | to see stance cars with -10 degrees or more of camber. My | race car runs -4.5 in the front, as an example, and my | buddy's drift car is running -6. | bluedino wrote: | Where does the 225 tire on a 10" wheel come in? I ask | because drag racers will run a 275mm on a 14 or 15 inch | wheel so there must be a reason the wannabe drift kids do | it. | neuralRiot wrote: | The drag racers use such tire/rim ratio to make a | flexible connection to the ground and improve traction. | This https://ssl.c.photoshelter.com/img- | get2/I0000uzO7iSXj_JU/fit... is whathappen when your only | way to transmit 10k Hp to the ground is 2 pieces of | rubber. | mulmen wrote: | Short sidewalls ostensibly offer better cornering because | there is less deflection in the sidewall. They also | enable the use of larger brakes. Drag racers don't care | about this since they don't turn unless something has | gone wrong and they have lots of room to slow down. In | drag racing the sidewall is used like a coil spring to | capture torque before moving forward and then transmit it | to the course. | | Stance kids and all their variants do things because it | looks good to them. | photoGrant wrote: | Of course. The more sideways you are the more you'd still | like your wheels to point the direction of intended travel! | stevenjgarner wrote: | Puts my rage in perspective when the Chevrolet Silverado devours | > 22ft with its turning radius. | The_suffocated wrote: | Near the end of the article: > As impressive as | the video is, there is no word whether this product is ready for | market or not. | ChrisMarshallNY wrote: | That's cool. | | However (there's always a fly in the ointment), we'd need to see | how robust it is (front axles take a real beating), and how | expensive it is to equip and maintain. | UniverseHacker wrote: | Despite what the article says, this is only for RWD cars with | no front axles. | sloucher wrote: | One of the things that make this possible is the sudden increase | in space in [what was] the engine compartment, now that electric | cars are more common. | | Most small cars with petrol engines have nowhere near enough | space for the wheel to turn like that. | throwaway0a5e wrote: | Even in the rear of the vehicle where things don't need to | steer packaging is a huge priority. Removing the engine won't | change this. The tire was never really trying to conflict with | the engine anyway. It was the structural bits of the car that | kinda need to be there to support the front and the suspension | that got in the way. | rootusrootus wrote: | I expect the real packaging issue with a FWD car would be the | driveshafts. | throwaway0a5e wrote: | Exactly. If they had a CV shaft that could support these | operating angles at an only slightly insane price point | they would be telling us because that's a much bigger | accomplishment than a steering linkage that has a lot of | angle. Forklifts have a lot of angle and nobody cares. It's | a question of straightforward tradeoffs. | asdff wrote: | The engine compartment doesn't have to be in the front | Brian_K_White wrote: | Now you're making me imagine a complicated arrangement with | essentially 2 vertical hinges, where the wheel only swings out | away from the car regardless which way it's turned. Then it | needs no more room in the engine bay. It would rattle and klunk | near the center/straight position, but aside from that it's | physically possible. It would probably need some kind of belt | to drive the axle so that it can bend around a pulley and a | changing angle while still delivering the power. Ok I've gone | off the deep end... | amelius wrote: | From the article: | | "EasyTurn is suitable for vehicles with rear-wheel drive, the | usual setup in electric cars." | ddingus wrote: | I had an 80's era Vanagon with an insane turning angle. Lots of | room in the front wheel wells. Could U turn that thing on most | residential streets with cars parked on one side. | anuvrat1 wrote: | Drifters would love this. | Damogran6 wrote: | Lots of similarities to drifting car parts...also: Doesn't look | compatible with FWD | giarc wrote: | Looks cool, but is this a solution in search of a problem? | tiagod wrote: | I drive (and parallel park) in Lisbon regularly and having this | on my car would be a godsend. | wolrah wrote: | > Looks cool, but is this a solution in search of a problem? | | The problem of maneuvering vehicles in tight spaces and | parallel parking with limited room is a real one that anyone | can observe by just standing around in places with heavily | occupied streetside parking. | | Whether that problem is annoying enough to the right people to | be worth the cost of this system is a different matter, but | there is definitely no problem searching required here. | ummonk wrote: | I'm mildly amused that the animation for the second car parallel | parking seems to be placed too far forward and thus scrapes the | bumper of the car in front. | exar0815 wrote: | One thing I am wondering - i mean, everyone in the US knows Ford | invented the automobile and the diesel engine was named after an | american called Vin, but since when is ZF a US-company? | mulmen wrote: | Since 2016: | https://en.wikipedia.org/wiki/ZF_Friedrichshafen#ZF-TRW. | iancmceachern wrote: | It should read "mechanical engineers invent..." | moffkalast wrote: | Mechanical scientists! | [deleted] | donohoe wrote: | To be fair, you'd have to be a mechanic to invent an axle | Gravityloss wrote: | Since it seems to have rear wheel steering, if each wheel can | turn independently and enough, then the car could be rotated in | place. | fauria wrote: | That stationary spin is exactly what Rivian does, they call it | "tank turn": https://www.youtube.com/watch?v=7BkxjHkOvYY | mulmen wrote: | Can the system "tank turn" around an arbitrary point instead | of the center of the vehicle? I can imagine some situations | where a tank turn might be useful but a common scenario is | parallel parking where I would prefer to pivot around the | rear bumper. | CoffeeOnWrite wrote: | The article title says 80 degrees. My layman understanding is | rotating in place means 90 degrees. Correct me if I'm wrong. | dqpb wrote: | I prefer the surrealism of omni wheels. | moffkalast wrote: | This sort of thing keeps getting invented over and over for the | past hundred years but never seems to stick, and cars stay | impossible to parallel park. | dsego wrote: | impossible? people do it every day | moffkalast wrote: | Well in the true sense of moving the car completely sideways. | They even had it working in the 50s on production cars to | some degree with the extra rear wheel. | hinkley wrote: | The Triumph Spitfire is notable for a few reasons. Besides having | a Center of Gravity lower than the axle, giving it zero body roll | when cornering, it was also a 12'11" long car with a 12'1" | turning radius. It could turn around in less than two car | lengths. | | I don't think that's 80deg but it's damned close. That vehicle | ceased production sometime around 1979. | [deleted] | Nick87633 wrote: | >Center of Gravity lower than the >axle, giving it zero body | roll >when cornering | | That's not exactly how it works, the center of gravity should | match up with the kinematic roll center of the axle linkage for | there to be zero rolling moment. | mrcarruthers wrote: | I have one. It's a RWD car and the front wheels can turn so | much that instead of turning, the car will actually start to | drag the front wheels unless you're going really slow. | jeffreygoesto wrote: | Can confirm. I installed a steering angle limiter to reduce | the chance of too much stress on the joints. And yes, the | Spitfire can corner until it flies without rolling. Might be | me adding a lot to a low cog as well... ;-} | hinkley wrote: | RWD _and_ a high torque motor. I 'm pretty sure someone | somewhere has managed to snap some connecting rods in the | front end by being stupid. | jacquesm wrote: | All it takes is one sidewalk at that angle. At best it will | bend. | hinkley wrote: | Oh for sure. | | "I can make it!" | | <thump> | | <Narrator>: He didn't make it. | Marlon1788 wrote: | hope those tires can hold up | yesdocs wrote: | Queue the accidents that will occur by over correcting in | distress | deusum wrote: | Queue the accidents that will occur by taking no-look u-turns | on packed streets | FabHK wrote: | Related tidbit about London's black cabs: | | > London taxis must have a turning circle not greater than 8.535 | m (28 ft). One reason for this is the configuration of the famed | Savoy Hotel: the hotel entrance's small roundabout meant that | vehicles needed the small turning circle in order to navigate it. | That requirement became the legally required turning circles for | all London cabs, while the custom of a passenger's sitting on the | right, behind the driver, provided a reason for the right-hand | traffic in Savoy Court, allowing hotel patrons to board and | alight from the driver's side. | | https://en.wikipedia.org/wiki/Hackney_carriage#Vehicle_desig... | baybal2 wrote: | Zenst wrote: | The 1953 Bond minicar Mark C has a steering angle of 90 degree's: | | http://microcarmuseum.com/tour/bond-mk-c.html | idiotsecant wrote: | It was right in front of us all along, all you have to do is | mount a moped engine to your _one_ front wheel! On side note, | it says that it is an aluminum body, which must have been a | pretty fancy thing at the time! | laxatives wrote: | My Dyson vacuum cleaner has a mechanism that can steer in pretty | much every angle that isn't gimbal locked. If we're still talking | about things you could do without regard to practicality, it | could steer in 360 degrees in a RWD. ___________________________________________________________________ (page generated 2022-07-25 23:00 UTC)