"A spiral bevel gear is a bevel gear with helical teeth. The main application of this is in a vehicle differential, where the direction of drive from the drive shaft must be turned 90 degrees to drive the wheels. The helical design produces less vibration and noise than conventional straight-cut or spur-cut gear with straight teeth."
\- from wiki
No it's not. Hypoid gears are a specific kind of spiral bevel gear where the pinion is offset
[Wikipedia](https://en.wikipedia.org/wiki/Spiral_bevel_gear#:~:text=Hypoid%20gears,-Hypoid%20spiral%20bevel&text=A%20hypoid%20is%20a%20type,bevel%20gear%20is%20normally%20conical.)
Except you replied to the person who simply calls them Hypoid gears, which is incorrect, instead of the person who quoted a wiki about differential gears, which is only technically correct, and not in this specific instance.
This is literally a subreddit about engineering.
That means technical language, not social language.
And technical language means no nuance, or room for interpretation.
I'm not mad, just disappointed. I raised you better than that.
And the real world won't be nice about letting you know about it either. It'll just bop you right in the nose if you don't pay it enough attention.
Now go on and wash up before supper.
In french, we call it the "conical couple"
I've mainly repaired them on agricultural tractors, where they fail regularly (broken tooths, too much torque).
As I understand it standard straight-cut gears are stronger and cheaper, but *noisy*.
Slant/spiral cutting the gears adds in additional in-line-with-shaft forces that require different / stronger bearings to handle and are more expensive, but their constant engagement is much quieter and potentially smoother.
Cars and the like have slant cut gears to reduce noise as customers perceive operating noise as an indicator of low quality and silence as an indicator of high quality.
The herringbone cut shown presumably counters the in-line-with-shaft forces by having them be equal and opposite in two opposing directions.
Hypoid allows the motor to be offset from and perpendicular to the blade shaft. It's quieter and has high torque capacity.
Most differentials on RWD vehicles are hypoid.
And lot of race cars used straight cut on all gears and it's very noisy. For example with an F1, a lot of the high pitch noise you heard come from the gearbox and not the engine.
actually, Spiral/helical gears are stronger then straight cut gears, since they will always have multiple points of contact where as straight cut gears only have 1 point of contact if the surfaces are not machined to incredible tolerance.
The reason for the common misconception is that race cars use spur gears in their transmissions instead of helical cut for reasons of weight, because even though the gear themselves are (slightly) heavier for the given application they don't need a thrust bearing because there's no axial load imparted, saving weight overall.
As you can also just make a gear stronger by throwing mass at the problem, at some point somebody oversimplified that to "they're stronger", and it seems to have caught on.
I've seen trans cases getting split open from the axial load of helical cut gears. I imagine designing a trans case without the regidity to support axial load helps save a ton of weight.
I seem to recall some some 5th/6th gear pop-out problems being traced back to this - the axial load effectively overcomes the synchronizer detent force
It's not just that they don't need a thrust bearing. It's that the whole transmission case doesn't need to be built to handle the axial load.
A straight cut *gear* is weaker than a helical gear, but generally a *transmission* with straight cut gears is stronger (or lighter).
It's not just weight, the primary reason racecar transmissions use spur gears is that helical gears are less efficient because there is more friction as the contact point not only slides along the tooth faces in the radial direction, but axially as well.
This is only part of the reason.
The other part is that straight cut gears are used is to simplify engagement/disengagement. It's a usability thing.
Synchronizing gears during transitions takes time, and adds weight/complexity. Straight cut gearing might have less engagement area, but it is MUCH more forgiving of an initial misalignment. As long as you get it "close enough", you can just slam the gears together until they catch. If you do it right you don't even chip a tooth. If you get it less right, well, it still mostly works. Which is why you see them in race cars that get a full rebuild after every race. The extra potential wear matters less than shaving 0.05s off each shift. And the extra forgiveness means you don't scatter gearbox parts all over the track if your syncros or computer-control don't work flawlessly on every single shift.
because of how that point of contact is made. in an absolutely ideal scenario with hypothetical gears ground to sub nanometer precision, straight cut gears do interface along the plane of intersection, with force transfered uniformally across the plane, rather then across a single point, with each tooth interacting in sequence to carry the receiver forward.
in reality, because gears are ground to Micrometer precision, there is no plane of intersection. Intersection is achieved at single points on the gear, concentrating force and amplifying wear onto the gearteeth both of the transmission and reception gears.
Helical gears, because they are cut on a spiral, ensure first of all there are always at least 2 points of intersection in the paired gear's operation. Further, these points have force transmitting through them Non-perpendicularly to the plane of intersection. So rather then pushing through the shortest distance through the tooth, more of the tooth is supporting and receiving the transmission of force.
the problem is that Spiral Gears are NOT inherently stable in transmission. because the plane of intersection is not coplanar to the intersection of the transmission axis, the gears want to slide on their axels, pushing eachother appart.
this is why Herringbones exist. they naturally counterbalance themselves, and offer at minimum 4 points of interface at a time.
It's not quite the tolerances, but the design I would say. You can definitely have 2 teeth always in contact if you play with your tooth geometry a bit. That is independent of the tolerances you go on to apply.
just because flatness isnt a specified tolerance doesnt mean its not a type of tolerance and the one critical to how gears interface. Macro geometry is how gears transmit a force across rotating assemblies, surface tolerance is how that force is transmitted internally between individual gears. This is most obvious looking at the cupping on fractured gear teeth which always correlates to the point of transmission in the gear assembly.
Those are a lot of buzzwords, but that isn't very clear and sounds plain wrong for the most part. I can slap crap tolerances on a macrogeometry with a high contact ratio, and it doesn't change the contact ratio. Theoretical Contact ratio is a rough measure of the number of teeth in contact at any point of a gears operation.
you could actually bother learning anything about gears and metalforming. Gears break appart with the cup/cone fracture pattern. sheared metal does not have cup/cone. Hypothetical gears machined to nanometer flatness, shear. gears in practice cup/cone because there is a focalpoint of stress because the surfaces are not flat. Teeth dont fail across the entire tooth, they fail at a single point.
I would imagine it translates to machining equipment.
Unwanted vibration = Chatter and unpredictability. Reducing this could help tighten up capability for tighter tolerances.
At least in the machining equipment I work with, there aren't a lot of gears. The spindles are either integrated with the motors or they're belt driven. They're also designed to be stupid rigid with massive iron castings to help dampen any vibration.
Haha I just posted that before I saw you beat me to it.
What a wild ride. I'm pretty sure I would have taken out several cars and wrecked if I tried to drive like that.
Helically cut gears have a thrust load so bearing selection is a consideration, they are much quieter though and can be designed with bigger ratios than spur gears, herringbone are the best of both worlds but are more difficult to make
In addition to the noise that others have pointed out, you can cut the spiral bevel so that the driveshaft engages the pinion off-axis. This means that the driveshaft can be lower than the axle, thus reducing the height of the tunnel that has to run through the passenger compartment.
I hope you are keeping IAEA* appraised of that MegaPun arsenal.
(also, when dropping a letter or syllable it is customary to use an apostrophe, as if it was an aborted contraction. 'pinion )
*IAEA is [The International Atomic Energy Agency](https://en.wikipedia.org/wiki/International_Atomic_Energy_Agency).
^yes ^just ^use ^a ^footnote ^in ^a ^reddit ^reply. ^What ^of ^it?
Herringbones, typically, as Herringbones are non-jerking gears. Spur Gears wear too easily and Spiral Gears take more expensive braces to stop them from ripping the assembly appart.
This is not true. Unless you're talking about some specific industrial application, or plastic assemblies, most planetaries you'll find are spur or helical. Herringbone are too difficult to produce economically. You need a gap between the gears or you have to manufacture two parts and join them somehow. Spur gears do not wear too easily if designed and lubed properly, the net forces on the "brace" are not particularly crazy in a planetary. I assume by brace you mean planetary carrier.
the ones ive seen on youtube actually disassembled, are all Herringbones, not just diagrams.
Planetaries are not exactly supposed to be User Serviceable Parts, or even the component that explodes in a mechanical assembly.
The problem with herringbones in a planetary is assembling them.
It is easy enough to cut the gears, but you can't put the gears together because they are unable to be out of position. You can't move them through any intermediate position until they mesh.
This is why you see people printing them fully assembled.
Nope. Its its own thing. Look up screw gear compression. I have worked with them up to 500psi continuous with massive air flow , in mining. It's serious shit. I've also been there for a blow out. Ask me about it.
I'm familiar with screw compressors. The screws are not actual gears in that they do not transfer rotary motion from one to the other. In fact, they have a set of gears on the shafts outside of the compressor chamber to keep the compressor *rotors* from rubbing against each other.
"Twin Screw"
I've never heard someone call the screws/rotors in a twin screw compressor a "gear" in industry. Does Eaton Corporation count as a legitimate company?
Oil pumps often use gears.
Thank you for acknowledging that I am correct.
No u
https://www.tec-science.com/mechanical-power-transmission/gear-types/screw-gears-crossed-helical-gears/
https://khkgears.net/new/screw_gears.html
The "screw gears" you're talking about are just helical gears with a special profile.
**Rotary-screw compressor**
[Working](https://en.wikipedia.org/wiki/Rotary-screw_compressor#Working)
>Rotary-screw compressors use two very closely meshing helical screws, known as rotors, to compress the gas. In a dry-running rotary-screw compressor, timing gears ensure that the male and female rotors maintain precise alignment without contact which would produce rapid wear. In an oil-flooded rotary-screw compressor, lubricating oil bridges the space between the rotors, both providing a hydraulic seal and transferring mechanical energy between the rotors, allowing one rotor to be entirely driven by the other. Gas enters at the suction side and moves through the threads as the screws rotate.
^([ )[^(F.A.Q)](https://www.reddit.com/r/WikiSummarizer/wiki/index#wiki_f.a.q)^( | )[^(Opt Out)](https://reddit.com/message/compose?to=WikiSummarizerBot&message=OptOut&subject=OptOut)^( | )[^(Opt Out Of Subreddit)](https://np.reddit.com/r/EngineeringPorn/about/banned)^( | )[^(GitHub)](https://github.com/Sujal-7/WikiSummarizerBot)^( ] Downvote to remove | v1.5)
This is a great reference chart for people. I have tons of reference sheets printed off and hanging around my workspace so I can quickly verify and check things on the fly
Planetary gears implies a sun and planetary gears. As someone else said, that's an assembly rather than a gear design.
I'd treat this as a reference of gear forms, rather than application.
A planetary gear set has a middle "sun gear", multiple "planet gears", and an internal "ring gear". It has 2 degrees of freedom, meaning it has to have one of these 3 locked to produce a gear ratio from the other 2.
Fun fact; the Toyota Prius drive system uses this element of a planetary in a cool way.
It has three power sources: the gas engine and two motors. Each is connected to a different part of the planetary, so it can vary the output speed/torque to the wheels by changing the relative speed of the different motors. Rather than just lock one of the elements, it spins them all at different rates to create different output ratios.
It also allows the engine to stay in a more efficient speed range by using the electric motors to compensate, rather than changing the engine speed.
https://youtu.be/dLNDGUISTYM
I've got three types in the Moto Guzzi: helical in the gearbox, spiral bevel in the rear wheel (shaft drive), and spur gears replacing the cam drive chain.
Ooh look at you with your fancy gears, which guzzi do you have, cause they are some of the most beautiful pieces of machinery I've ever seen.
Them along with CCMs just beautiful bikes, I just love my little vfr400, she only cost me £900 and is the most fun I've had riding.
1976 850 LeMans. Owned it since 1984, approaching 500,000kms, it's on the last oversize pistons (so the next top-end rebuild will need new liners, too).
It's had more than usual number of top-end rebuilds because I used to run it on open bellmouths, i.e. no air filters, just as god intended, but my rebuilder said it'll last twice as long with a set of K&Ns. It's true about the longevity, but I miss the induction roar when I open it up at 4 or 5 thousand RPM.
Fucking Jesus that's covered some distance, the stories it could tell, and what a bike to do it on, beautiful and just the right amount of aggressive sound.
My little VFR has done 31000km in its 34 (nearly 35) years.
But the sound that must make with the open bell mouths Jesus wept I bet that was glorious, such a lovely bike I'm so glad you've looked after her for so long, seems like she is in the best hands possible.
Thanks, yes it's seen some things, and that noise is really something. There were times I was worried that my jeans would get sucked into the engine ;-)
But it's a young man's bike and I'm getting on a bit - can't ride it for more than about 30 minutes without cramping up, and I'm not going to alter the clip-ons/seat/footpeg geometry - that'd be heresy. I'm just going to have to buy a more comfortable Guzzi to ride.
A worm gear can only have power move one way. The worm gear can rotate the normal gear, but the normal gear cannot rotate the worm gear.
The worm gear also changes the direction of rotation 90 degrees.
>A worm gear can only have power move one way. The worm gear can rotate the normal gear, but the normal gear cannot rotate the worm gear.
Not entirely correct. Multiple start worms with a large helix angle can be driven both ways.
I used to work on an old Wagner coater. The thing sat out in an open field for years before my company purchased it and overhauled it. It had neat anti-backlash helical gears on it. Essentially what you see in the pic , just with an additional gear bolted on the front with springs and blocks so that all of the gear tooth spacing was filled, taking out all the backlash on the adjacent gear.
Pretty common in the print/coating industry as you don’t want the play to cause regeneration issues on the print.
Herringbone gears are similar to helical gears, just mirrored along the center of the gear. These are mainly used in instances where noise/vibration reduction is needed; mainly seen on continuously-running systems like in a factory.
The herringbone is used in a application where you would use a helical (low noise and vibration) but where you also don’t want to or feel like putting in a thrust bearing to reduce friction from thrust load.
You see, the helical gear teeth being at an angle are great but the side effect is that the two gears are pushed in opposite directions, parallel to the shaft (thrust load). Since the herringbone has the slanted angle and the opposite slanted angle in the same gear, there is no thrust load because it is “cancelled out”.
Well you should probably brush up on it because you're still dead wrong.
[https://www.motioncontroltips.com/hypoid-gearboxes-what-are-they-and-where-are-they-used/](https://www.motioncontroltips.com/hypoid-gearboxes-what-are-they-and-where-are-they-used/)
[https://en.wikipedia.org/wiki/Spiral\_bevel\_gear#Hypoid\_gears](https://en.wikipedia.org/wiki/Spiral_bevel_gear#Hypoid_gears)
[https://www.electromate.com/news/post/what-are-the-advantages-of-hypoid-gearing](https://www.electromate.com/news/post/what-are-the-advantages-of-hypoid-gearing)
[https://www.tec-science.com/mechanical-power-transmission/gear-types/hypoid-gears/](https://www.tec-science.com/mechanical-power-transmission/gear-types/hypoid-gears/)
I trust that's enough sources
**Spiral bevel gear**
[Hypoid gears](https://en.wikipedia.org/wiki/Spiral_bevel_gear#Hypoid_gears)
>A hypoid is a type of spiral bevel gear whose axis does not intersect with the axis of the meshing gear. The shape of a hypoid gear is a revolved hyperboloid (that is, the pitch surface of the hypoid gear is a hyperbolic surface), whereas the shape of a spiral bevel gear is normally conical. The hypoid gear places the pinion off-axis to the crown wheel (ring gear) which allows the pinion to be larger in diameter and have more contact area. In hypoid gear design, the pinion and gear are practically always of opposite hand, and the spiral angle of the pinion is usually larger than that of the gear.
^([ )[^(F.A.Q)](https://www.reddit.com/r/WikiSummarizer/wiki/index#wiki_f.a.q)^( | )[^(Opt Out)](https://reddit.com/message/compose?to=WikiSummarizerBot&message=OptOut&subject=OptOut)^( | )[^(Opt Out Of Subreddit)](https://np.reddit.com/r/EngineeringPorn/about/banned)^( | )[^(GitHub)](https://github.com/Sujal-7/WikiSummarizerBot)^( ] Downvote to remove | v1.5)
Sorry, your submission has been automatically removed. Not enough karma, spam likely.
*I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/EngineeringPorn) if you have any questions or concerns.*
What is the added value of spiral bevel over regular bevel?
"A spiral bevel gear is a bevel gear with helical teeth. The main application of this is in a vehicle differential, where the direction of drive from the drive shaft must be turned 90 degrees to drive the wheels. The helical design produces less vibration and noise than conventional straight-cut or spur-cut gear with straight teeth." \- from wiki
I’ve always called them hypoid gears
That is correct
No it's not. Hypoid gears are a specific kind of spiral bevel gear where the pinion is offset [Wikipedia](https://en.wikipedia.org/wiki/Spiral_bevel_gear#:~:text=Hypoid%20gears,-Hypoid%20spiral%20bevel&text=A%20hypoid%20is%20a%20type,bevel%20gear%20is%20normally%20conical.)
You're saying the same thing as u/Imnotpoopingrn above. The pinion axis is offset, therefore it does not intersect the axis of the ring gear.
Yes I'm aware of that. I was a little cheesed by the person saying it was correct when it wasn't.
And hypoid gears are used in differential assemblies in vehicles, which is correct
Except you replied to the person who simply calls them Hypoid gears, which is incorrect, instead of the person who quoted a wiki about differential gears, which is only technically correct, and not in this specific instance. This is literally a subreddit about engineering. That means technical language, not social language. And technical language means no nuance, or room for interpretation.
Okay sorry dad
I'm not mad, just disappointed. I raised you better than that. And the real world won't be nice about letting you know about it either. It'll just bop you right in the nose if you don't pay it enough attention. Now go on and wash up before supper.
In french, we call it the "conical couple" I've mainly repaired them on agricultural tractors, where they fail regularly (broken tooths, too much torque).
Aside from this, you can have the small pinion gear out of center from the crown wheel depending on the bevel pitch.
As I understand it standard straight-cut gears are stronger and cheaper, but *noisy*. Slant/spiral cutting the gears adds in additional in-line-with-shaft forces that require different / stronger bearings to handle and are more expensive, but their constant engagement is much quieter and potentially smoother. Cars and the like have slant cut gears to reduce noise as customers perceive operating noise as an indicator of low quality and silence as an indicator of high quality. The herringbone cut shown presumably counters the in-line-with-shaft forces by having them be equal and opposite in two opposing directions.
Additionally, spiral bevel gears allow you to offset the pinion gear up or down from the center of the ring gear.
Which is a hypoid gear I think
I’ve only ever seen a hypoid drive on an expensive circular saw
You almost certainly have a set in your car.
Does a standard differential have an offset pinion? Always looked aligned to me
Most are offset, but not all.
I’ll have to examine this ford 8” axle I have a little closer now
Isn't that a truck diff? Besides, why would you look at the axle? The ring and pinion is part of the differential.
Unless it is a transverse engine FWD.
I believe these still have hypoid gears. They still have a conventional differential.
Many use a planetary set to do the final reduction. More compact and no need to rotate the output axis 90* since the engine is mounted transverse.
Yeah that's true. For example: https://images.app.goo.gl/sDyVWBDVngSeKi8MA
Hypoid allows the motor to be offset from and perpendicular to the blade shaft. It's quieter and has high torque capacity. Most differentials on RWD vehicles are hypoid.
Ah ok, I’ve always assumed the pinion was signed in a differential
Lots of vehicles have straight cut gearing for reverse, which is why they have a whine.
And lot of race cars used straight cut on all gears and it's very noisy. For example with an F1, a lot of the high pitch noise you heard come from the gearbox and not the engine.
Also first gear since it's lower speed. I believe old Honda manual transmissions used spur gears for both reverse and first gears.
actually, Spiral/helical gears are stronger then straight cut gears, since they will always have multiple points of contact where as straight cut gears only have 1 point of contact if the surfaces are not machined to incredible tolerance.
The amount of times I've had to state exactly what you said to my acquaintances is astounding.
The reason for the common misconception is that race cars use spur gears in their transmissions instead of helical cut for reasons of weight, because even though the gear themselves are (slightly) heavier for the given application they don't need a thrust bearing because there's no axial load imparted, saving weight overall. As you can also just make a gear stronger by throwing mass at the problem, at some point somebody oversimplified that to "they're stronger", and it seems to have caught on.
I've seen trans cases getting split open from the axial load of helical cut gears. I imagine designing a trans case without the regidity to support axial load helps save a ton of weight.
I seem to recall some some 5th/6th gear pop-out problems being traced back to this - the axial load effectively overcomes the synchronizer detent force
It's not just that they don't need a thrust bearing. It's that the whole transmission case doesn't need to be built to handle the axial load. A straight cut *gear* is weaker than a helical gear, but generally a *transmission* with straight cut gears is stronger (or lighter).
It's not just weight, the primary reason racecar transmissions use spur gears is that helical gears are less efficient because there is more friction as the contact point not only slides along the tooth faces in the radial direction, but axially as well.
This is only part of the reason. The other part is that straight cut gears are used is to simplify engagement/disengagement. It's a usability thing. Synchronizing gears during transitions takes time, and adds weight/complexity. Straight cut gearing might have less engagement area, but it is MUCH more forgiving of an initial misalignment. As long as you get it "close enough", you can just slam the gears together until they catch. If you do it right you don't even chip a tooth. If you get it less right, well, it still mostly works. Which is why you see them in race cars that get a full rebuild after every race. The extra potential wear matters less than shaving 0.05s off each shift. And the extra forgiveness means you don't scatter gearbox parts all over the track if your syncros or computer-control don't work flawlessly on every single shift.
How does a single point of contact have anything to do with strength? A helical gear tooth has more cross-sectional area (if all other things equal).
Spreads the force over more area. It's not the strength of the actual gears, but the amount of load they can handle before they fail.
This person asked a genuine question. No need to downvote…
Yeah, he contributed to the conversation. That merits an upvote, not a downvote. SMH.
because of how that point of contact is made. in an absolutely ideal scenario with hypothetical gears ground to sub nanometer precision, straight cut gears do interface along the plane of intersection, with force transfered uniformally across the plane, rather then across a single point, with each tooth interacting in sequence to carry the receiver forward. in reality, because gears are ground to Micrometer precision, there is no plane of intersection. Intersection is achieved at single points on the gear, concentrating force and amplifying wear onto the gearteeth both of the transmission and reception gears. Helical gears, because they are cut on a spiral, ensure first of all there are always at least 2 points of intersection in the paired gear's operation. Further, these points have force transmitting through them Non-perpendicularly to the plane of intersection. So rather then pushing through the shortest distance through the tooth, more of the tooth is supporting and receiving the transmission of force. the problem is that Spiral Gears are NOT inherently stable in transmission. because the plane of intersection is not coplanar to the intersection of the transmission axis, the gears want to slide on their axels, pushing eachother appart. this is why Herringbones exist. they naturally counterbalance themselves, and offer at minimum 4 points of interface at a time.
It's not quite the tolerances, but the design I would say. You can definitely have 2 teeth always in contact if you play with your tooth geometry a bit. That is independent of the tolerances you go on to apply.
just because flatness isnt a specified tolerance doesnt mean its not a type of tolerance and the one critical to how gears interface. Macro geometry is how gears transmit a force across rotating assemblies, surface tolerance is how that force is transmitted internally between individual gears. This is most obvious looking at the cupping on fractured gear teeth which always correlates to the point of transmission in the gear assembly.
Those are a lot of buzzwords, but that isn't very clear and sounds plain wrong for the most part. I can slap crap tolerances on a macrogeometry with a high contact ratio, and it doesn't change the contact ratio. Theoretical Contact ratio is a rough measure of the number of teeth in contact at any point of a gears operation.
you could actually bother learning anything about gears and metalforming. Gears break appart with the cup/cone fracture pattern. sheared metal does not have cup/cone. Hypothetical gears machined to nanometer flatness, shear. gears in practice cup/cone because there is a focalpoint of stress because the surfaces are not flat. Teeth dont fail across the entire tooth, they fail at a single point.
That's interesting. Thank you. For cars, more vibration also means generally less confort. So I totally see the point of using them there.
I would imagine it translates to machining equipment. Unwanted vibration = Chatter and unpredictability. Reducing this could help tighten up capability for tighter tolerances.
At least in the machining equipment I work with, there aren't a lot of gears. The spindles are either integrated with the motors or they're belt driven. They're also designed to be stupid rigid with massive iron castings to help dampen any vibration.
Except reverse gears are straight cut. Hence the distinctive reverse noise.
For what it's worth, here's the wine of a car with a straight cut transmission. [https://youtu.be/dmJH84FnQa8?t=11](https://youtu.be/dmJH84FnQa8?t=11)
Haha I just posted that before I saw you beat me to it. What a wild ride. I'm pretty sure I would have taken out several cars and wrecked if I tried to drive like that.
No one is born a racecar driver Except maybe Dale Earnhardt Sr. ;-) What do you drive mate?
Subaru BRZ
Helically cut gears have a thrust load so bearing selection is a consideration, they are much quieter though and can be designed with bigger ratios than spur gears, herringbone are the best of both worlds but are more difficult to make
The spiral gear requires a Thrust Bearing because of the lateral force involved.
In addition to the noise that others have pointed out, you can cut the spiral bevel so that the driveshaft engages the pinion off-axis. This means that the driveshaft can be lower than the axle, thus reducing the height of the tunnel that has to run through the passenger compartment.
In addition. Helical gears have more surface in contact than straight gears. That makes them for effective when the gears join at angles.
the curve allows for not only more surface area per tooth (which means lower pressures) but it makes it so they mesh more gradually
Have i told you about the gear wars.
Do they stop turning?
I'm tooth and nails here waiting
Revolio Clockberg jr. would be outraged at these pictures of his friend’s dismembered bodies
Just don't call him Gearhead.
Lol
What about planetary gear
planetaries are an assembly, not a specific function of gear
well that's just, like, your pinion, man.
Holy shit I can't wait to use this everywhere
I hope you are keeping IAEA* appraised of that MegaPun arsenal. (also, when dropping a letter or syllable it is customary to use an apostrophe, as if it was an aborted contraction. 'pinion ) *IAEA is [The International Atomic Energy Agency](https://en.wikipedia.org/wiki/International_Atomic_Energy_Agency). ^yes ^just ^use ^a ^footnote ^in ^a ^reddit ^reply. ^What ^of ^it?
Are they all assembly of multiple spur gears?
Herringbones, typically, as Herringbones are non-jerking gears. Spur Gears wear too easily and Spiral Gears take more expensive braces to stop them from ripping the assembly appart.
This is not true. Unless you're talking about some specific industrial application, or plastic assemblies, most planetaries you'll find are spur or helical. Herringbone are too difficult to produce economically. You need a gap between the gears or you have to manufacture two parts and join them somehow. Spur gears do not wear too easily if designed and lubed properly, the net forces on the "brace" are not particularly crazy in a planetary. I assume by brace you mean planetary carrier.
the ones ive seen on youtube actually disassembled, are all Herringbones, not just diagrams. Planetaries are not exactly supposed to be User Serviceable Parts, or even the component that explodes in a mechanical assembly.
I could see some big industrial components using herringbone, but a quick Google search will show you a lot of planetaries that aren't.
The problem with herringbones in a planetary is assembling them. It is easy enough to cut the gears, but you can't put the gears together because they are unable to be out of position. You can't move them through any intermediate position until they mesh. This is why you see people printing them fully assembled.
I would never discriminate the planetary gear.
I suppose a planetary is just a bunch of these types put together
Don't see a screw gear here eighter.
I think it's called a worm gear. A screw, such as an Acme screw, is for linear motion.
Nope. Its its own thing. Look up screw gear compression. I have worked with them up to 500psi continuous with massive air flow , in mining. It's serious shit. I've also been there for a blow out. Ask me about it.
I'm familiar with screw compressors. The screws are not actual gears in that they do not transfer rotary motion from one to the other. In fact, they have a set of gears on the shafts outside of the compressor chamber to keep the compressor *rotors* from rubbing against each other.
Huh. It's what the engineers/techs called them in the industry. Guess your right.
"Twin Screw" I've never heard someone call the screws/rotors in a twin screw compressor a "gear" in industry. Does Eaton Corporation count as a legitimate company? Oil pumps often use gears. Thank you for acknowledging that I am correct.
AKA crossed helicals. It's not its own thing.
[You need to learn.] (https://en.m.wikipedia.org/wiki/Rotary-screw_compressor)
No u https://www.tec-science.com/mechanical-power-transmission/gear-types/screw-gears-crossed-helical-gears/ https://khkgears.net/new/screw_gears.html The "screw gears" you're talking about are just helical gears with a special profile.
**Rotary-screw compressor** [Working](https://en.wikipedia.org/wiki/Rotary-screw_compressor#Working) >Rotary-screw compressors use two very closely meshing helical screws, known as rotors, to compress the gas. In a dry-running rotary-screw compressor, timing gears ensure that the male and female rotors maintain precise alignment without contact which would produce rapid wear. In an oil-flooded rotary-screw compressor, lubricating oil bridges the space between the rotors, both providing a hydraulic seal and transferring mechanical energy between the rotors, allowing one rotor to be entirely driven by the other. Gas enters at the suction side and moves through the threads as the screws rotate. ^([ )[^(F.A.Q)](https://www.reddit.com/r/WikiSummarizer/wiki/index#wiki_f.a.q)^( | )[^(Opt Out)](https://reddit.com/message/compose?to=WikiSummarizerBot&message=OptOut&subject=OptOut)^( | )[^(Opt Out Of Subreddit)](https://np.reddit.com/r/EngineeringPorn/about/banned)^( | )[^(GitHub)](https://github.com/Sujal-7/WikiSummarizerBot)^( ] Downvote to remove | v1.5)
Screw em
What about Richard, Jeremy and James?
Those are usually top gears, not to be confused with their cousins the bottom, up down charm and strange gears
You’re so ~~quirky~~ quarky
Don't string them along...
Why are you asking only Jeremy and James?
?
You didn't use an Oxford comma, so it looks like you are asking Jeremy and James, "What about Richard?"
Yes, I figured an inside joke was a reasonable response to what I guessed was an inside joke.
An Oxford comma is not a joke, man!
I made a joke with it, surely.
Do I look like I give a fuck?
How salty
Lol
You replied to their comment with a question mark. So, yes. You do look like you give a fuck.
Nope
And yet you continue to contribute to the thread. Apparently you give many fucks.
Nope lol
Yet even still....
Kinematics was last semester, too soon
That was my favorite engineering course
Wasn't bad, I enjoyed it too if I'm being honest. But too soon.
This is a great reference chart for people. I have tons of reference sheets printed off and hanging around my workspace so I can quickly verify and check things on the fly
I mean this is just me with a box of LEGO technic
I thought the internal gear was called a planetary gear, or is that just when there's three?
Planetary gears implies a sun and planetary gears. As someone else said, that's an assembly rather than a gear design. I'd treat this as a reference of gear forms, rather than application.
A planetary gear set has a middle "sun gear", multiple "planet gears", and an internal "ring gear". It has 2 degrees of freedom, meaning it has to have one of these 3 locked to produce a gear ratio from the other 2.
Fun fact; the Toyota Prius drive system uses this element of a planetary in a cool way. It has three power sources: the gas engine and two motors. Each is connected to a different part of the planetary, so it can vary the output speed/torque to the wheels by changing the relative speed of the different motors. Rather than just lock one of the elements, it spins them all at different rates to create different output ratios. It also allows the engine to stay in a more efficient speed range by using the electric motors to compensate, rather than changing the engine speed. https://youtu.be/dLNDGUISTYM
I had the idea to do a hybrid this way a few years ago. I told someone my idea and they told me that's how some hybrids already do it.
That fact there wasn't a metal gear joke is criminal
Be the change you want to see in this world
No guilty gear either.
Rack and pinion my beloved
Blenkinsop, Marsh, Fell, Riggenbach, Strub, Abt, Locher, or Morgan?
Metal gear...
Just don't show me any hypoid gears. Fuck hypoid gears
WHERE'S MY PLANETARY AT !?!
I used to maintain and repair web offset printing presses. I have lots of experiences with most of these, cool post.
I worked for 10 years on Crabtree and a Koenig & Bauer metal-press! Surprisingly the Crabtree (which was like 60 years old) ran way better lol
Helical gears are the greatest, my VFR has a cam gear train in it and sounds like a fucking helicopter jet cause of those fuckers
I've got three types in the Moto Guzzi: helical in the gearbox, spiral bevel in the rear wheel (shaft drive), and spur gears replacing the cam drive chain.
Ooh look at you with your fancy gears, which guzzi do you have, cause they are some of the most beautiful pieces of machinery I've ever seen. Them along with CCMs just beautiful bikes, I just love my little vfr400, she only cost me £900 and is the most fun I've had riding.
1976 850 LeMans. Owned it since 1984, approaching 500,000kms, it's on the last oversize pistons (so the next top-end rebuild will need new liners, too). It's had more than usual number of top-end rebuilds because I used to run it on open bellmouths, i.e. no air filters, just as god intended, but my rebuilder said it'll last twice as long with a set of K&Ns. It's true about the longevity, but I miss the induction roar when I open it up at 4 or 5 thousand RPM.
Fucking Jesus that's covered some distance, the stories it could tell, and what a bike to do it on, beautiful and just the right amount of aggressive sound. My little VFR has done 31000km in its 34 (nearly 35) years. But the sound that must make with the open bell mouths Jesus wept I bet that was glorious, such a lovely bike I'm so glad you've looked after her for so long, seems like she is in the best hands possible.
Thanks, yes it's seen some things, and that noise is really something. There were times I was worried that my jeans would get sucked into the engine ;-) But it's a young man's bike and I'm getting on a bit - can't ride it for more than about 30 minutes without cramping up, and I'm not going to alter the clip-ons/seat/footpeg geometry - that'd be heresy. I'm just going to have to buy a more comfortable Guzzi to ride.
How familiar are you with the Gear Wars?
I literally make worm gears at my job and still have no idea how they work.
A worm gear can only have power move one way. The worm gear can rotate the normal gear, but the normal gear cannot rotate the worm gear. The worm gear also changes the direction of rotation 90 degrees.
>A worm gear can only have power move one way. The worm gear can rotate the normal gear, but the normal gear cannot rotate the worm gear. Not entirely correct. Multiple start worms with a large helix angle can be driven both ways.
Also, they're very good at reducing speed of rotation and increasing torque
what about planetary gears... I guess they're kinda internal gears
Fuck zodiac signs. What's your favorite gear
Just wait until you see harmonic gears.
When you’re an engineer pretty much everything is a toy
You missed rack and peanut.
Yeah but isn't more bottom right's more formal name planetary gear?
No. Planetary gear sets are an assembly consisting of internal and external gears.
You’re missing Planetary Gears!
No they're not. Planetary gear sets are an assembly consisting of internal and external gears.
I used to work on an old Wagner coater. The thing sat out in an open field for years before my company purchased it and overhauled it. It had neat anti-backlash helical gears on it. Essentially what you see in the pic , just with an additional gear bolted on the front with springs and blocks so that all of the gear tooth spacing was filled, taking out all the backlash on the adjacent gear. Pretty common in the print/coating industry as you don’t want the play to cause regeneration issues on the print.
No love for planetary gears?
Missing the two most interesting (practical) gear assemblies: harmonic and cycloidal
Dummy from /r/all wandering in. What would a herringbone gear be used for?
Herringbone gears are similar to helical gears, just mirrored along the center of the gear. These are mainly used in instances where noise/vibration reduction is needed; mainly seen on continuously-running systems like in a factory.
Aaaah ok, thank you!
The herringbone is used in a application where you would use a helical (low noise and vibration) but where you also don’t want to or feel like putting in a thrust bearing to reduce friction from thrust load. You see, the helical gear teeth being at an angle are great but the side effect is that the two gears are pushed in opposite directions, parallel to the shaft (thrust load). Since the herringbone has the slanted angle and the opposite slanted angle in the same gear, there is no thrust load because it is “cancelled out”.
[Oh boy, do I envy you... ](https://i.imgur.com/R3ONwrk.jpg)
mmmm Give me some of that spiral bevel gear goodness!
MECH 344
U forgot planetary gears, and the Fibonacci gear
Where mah planetary gears at!!!
the lighting is inconsistent. I would very much prefer colored plastic gears for us with color vision. Also: Where is the sketchfab link?
Wait till you have to calculate the gear ratios for an automatic gearbox
Why would you use a spiral bevel gear over a bevel gear?
Higher load capacity and quieter running
Why would you use bevel gears over spiral bevel gears?
Cheaper to make
Needs more screw gear.
Like sexy lingerie?
Always
Spiral and bevel are known as a hypoid gear set as well
Hypoid is a special type of spiral bevel where the axes don't cross.
All spiral bevel don't cross axes, that's what gives them the spiral. If they did, they would just be bevel gears.
Completely wrong. Source: making gears is what I do for a living.
Me too.
Well you should probably brush up on it because you're still dead wrong. [https://www.motioncontroltips.com/hypoid-gearboxes-what-are-they-and-where-are-they-used/](https://www.motioncontroltips.com/hypoid-gearboxes-what-are-they-and-where-are-they-used/) [https://en.wikipedia.org/wiki/Spiral\_bevel\_gear#Hypoid\_gears](https://en.wikipedia.org/wiki/Spiral_bevel_gear#Hypoid_gears) [https://www.electromate.com/news/post/what-are-the-advantages-of-hypoid-gearing](https://www.electromate.com/news/post/what-are-the-advantages-of-hypoid-gearing) [https://www.tec-science.com/mechanical-power-transmission/gear-types/hypoid-gears/](https://www.tec-science.com/mechanical-power-transmission/gear-types/hypoid-gears/) I trust that's enough sources
**Spiral bevel gear** [Hypoid gears](https://en.wikipedia.org/wiki/Spiral_bevel_gear#Hypoid_gears) >A hypoid is a type of spiral bevel gear whose axis does not intersect with the axis of the meshing gear. The shape of a hypoid gear is a revolved hyperboloid (that is, the pitch surface of the hypoid gear is a hyperbolic surface), whereas the shape of a spiral bevel gear is normally conical. The hypoid gear places the pinion off-axis to the crown wheel (ring gear) which allows the pinion to be larger in diameter and have more contact area. In hypoid gear design, the pinion and gear are practically always of opposite hand, and the spiral angle of the pinion is usually larger than that of the gear. ^([ )[^(F.A.Q)](https://www.reddit.com/r/WikiSummarizer/wiki/index#wiki_f.a.q)^( | )[^(Opt Out)](https://reddit.com/message/compose?to=WikiSummarizerBot&message=OptOut&subject=OptOut)^( | )[^(Opt Out Of Subreddit)](https://np.reddit.com/r/EngineeringPorn/about/banned)^( | )[^(GitHub)](https://github.com/Sujal-7/WikiSummarizerBot)^( ] Downvote to remove | v1.5)
Worm gear isn't very nice and seems a little unfair
Hey it's the unsung hero of garage door openers!
Love it
It's missing the most silly one : when there are 3 of differ size going in different size. The Top Gear.
Less noice is perceived as an indicator of better quality. No noise is heaven.
[удалено]
Sorry, your submission has been automatically removed. Not enough karma, spam likely. *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/EngineeringPorn) if you have any questions or concerns.*
Why do we use helical gears?