[HN Gopher] Mechanics invent an axle that can achieve steering a...
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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.
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(page generated 2022-07-25 23:00 UTC)