Harmonic Drive Strain wave gear principle | Harmonic Drive SE

[@suddendilemma5137]

Just took one of these apart for the first time. What an amazing piece of metallurgy and engineering. Simply brilliant.

[@linezgames3893]

German engineering always the finests.

[@GeorgeSpacesOut]

No wonder I’m starting to see these in equatorial astronomy tracking mounts. Backlash is one of the challenges I encounter with long exposure astrophotography and this configuration seems to eliminate it. The high torque and load capacity of these drives also eliminates the need for counterweights. Outstanding piece of engineering here.

[@Just4TheFun100]

This sounds exactly like the plumbus skit on Rick and Morty

[@dhy5342]

Does the flexing produce heat and hardening (brittleness) in the materials used?

[@HarmonicDriveSE]

During the operation the Flexspline is permanently deformed by the rotating elliptical Wave Generator Bearing. However the Flexspline is only deformed within the elastical deformation zone, there is no plastic deformation during the operation. Assuming an operation within the catalog values the Flexspline is designed to endure the complete life of the gear. There is no hardening effect of the Flexspline during the operation of the gear. As every gear has a certain efficiency, of course also the strain wave gears produce heat caused by the thermal losses during the operation. When a gear is loaded with its nominal loads, the efficiency is typical within a range of 80…85%. The service life of the gear is typically not determined by the Flexspline but the Wave Generator Bearing which rotates with input speed and sees a high number of load cycles. When the gear is operated with rated torque and rated speed, the nominal life of a gear is 35000 h (HFUC, HFUS, etc.) or 50000 h (CSG, SHG, etc) at 50% probability of default. Harmonic Drive Strain wave gears have proven their reliability in many applications. They run in high volumes e.g. in robotic applications with high loads, enduring long service life. If you have further questions please feel free to contact us.

[@l0I0I0I0]

What is the longest these gears can last under low strain? Can they be designed to last longer?

[@johntheux9238]

Most of the strain is internal, it's not related to the load.

[@shodanxx]

I wonder if that could be made out of plastic. I'm guessing the outer race will be the most stressed surface

[@johntheux9238]

If you want a lower gear ratio you probably need to use plastic because of the increased elasticity.

[@johntheux9238]

Have you tried using amorphous metals?

[@samre3006]

What is the gear ratio achieved?

[@victabeer3960]

Ahhhhhhhh , so that's how those big KUKA robots hold a load with little effort . Cheers spline lords , you rule.

[@actin6901]

It's more about the precision tho due to the zero backlash, not the torque. A traditional gear could do the same load-wise. But robotics such as KUKA also needs the precision, hence this gear.

[@HimanshuGhadigaonkar]

Yeah.. also harmonic drive takes us less space and less volume to achieve back drivability and precision.. hence they are coupled with BLDC too.. if you were purely going for precision.. get a worm gear and a stepper.. no back drivability but excellent precision and very very low cost..

[@thatonethattalksalot7656]

An oval bearing!! Imagine spinning that in your hands!!

[@clarenceteo6833]

Wondering if the gears are waterproof :o

[@peterschlumpf9890]

Are the files (stl) availibel?;-)

[@joelgeorgeable]

Can anyone tell me which music is used?

[@HarmonicDriveSE]

Hi Joel, we produced the video with an agency that composed the music especially for the video.

[@joelgeorgeable]

@@HarmonicDriveSE any chance of getting the music?

[@Willthemusikfreunde]

Mind=Blown

[@pompotusoflove9126]

It's a great time to be a nerd!

[@roni51154]

Very nice model.

[@metiwalkthroughs]

Fascinating!

[@Chris5062284]

@iMIKEYSOTO Very high reduction ratios. Pretty clever.

[@willmason5774]

Did the designer happen to have a Spirograph set in his office? 🤨

[@oliverjamescarr]

WTF? I'm now more intrigued on how the elliptical ball bearing works O.o

[@azonicrider32]

just stop.

[@rpyrat]

@@azonicrider32 but he's right though

[@MRIFAILATCOD]

hmmmm thats clever, i just finished my transmission unit of my tafe course in automotive inspect and service. i wonder why we didnt get taught that

[@eatonjask]

Probably because Harmonic Drives aren't used in automobiles - very few cars needs a 100:1 reduction ratio, unlike the robotics industry.

[@samimas4343]

@@eatonjask care to explain what a reduction ratio is and what it is used for, please?

[@ИванИгревский]

In a very simple way, when drive rotates fast, wheel rotates slow (ratio). In automobile you don’t need to have such a low gear anywhere.

[@HimanshuGhadigaonkar]

@@ИванИгревский yes lowest gear ratio is sometimes seen in large earth moving vehicles.. or in small tractors..

[@TheSupaflyJedi]

What is the name of the background music? Anyone know?

[@nihilsson]

somebody dreamed about a caterpillar trapped in a tube chasing its tail and TADA Harmonic drive was born!

[@shodanxx]

This is the premise of the video ititled "Raytheon Engineer Microdoses Psychedelics Daily", you will probably appreciate watching it

[@kaardin6759]

1000th like, cool tech

[@iplmachining]

haw long before wears out

[@petermpeters]

nice!

[@MIKEYSOTO]

So whats this supposed to do?

[@rpyrat]

Transform a fast/low torque rotating motion into a slow/high torque rotating motion, within less space than traditional gear trains. This kind of transformation is done everywhere in engineering.

[@HistorywasBeautiful]

I love science

[@aristo188]

that explains the use of it in a kuka arm.

[@HarmonicDriveSE]

That's right. The integrated precision gears from Harmonic Drive AG ensure safe and reliable power transmission.

[@civicsr2cool]

wear life has got to be low?

[@bartdereu]

i have an industrial robot with two of these for the last 2 axes, been running 24h/7 for eight years straight without a problem.. Wear life must be great , i suppose :)

[@JP-in-OH]

The key is proper lube. Most robots utilize harmonic drives. Fanuc Robots recommend their grease, which is actually a fish oil base. Properly maintained, these drives last a very long time. The reason is the way the teeth engage. Watch the video again and you see the don't engage like a typical gear. Awesome mechanical invention.

[@playaspec]

I'm not doubting you, but the first thing I though while watching is that the extreme flexure of the flex spline must heat and fatigue the metal. How can it be flexible *and* make a good gear tooth surface? Seems like the obvious failure mode. If you do eventually have a problem there, will you get back to us? BTW: Do you know the reduction ratio of the units you have??

[@JP-in-OH]

The flex isn't extreme at all. Most of these drives the deflection is only a couple millimeters. So this doesn't generate heat. Friction in normal drives is what causes heat. The teeth move "in and out" as opposed to rolling across. I've worked with many robot manufacturers over the last 20 years. The weakness of these drives is the load. The can't handle a heavy load and are susceptible to damage when there is a jarring action. These drives are built for precision, not load.

[@HarmonicDriveSE]

The alloy steel of the Flexspline works similar to a spring. And the flexure is well within the fatigue limits of the metal. The losses are extremely low when compared to the gears (well over 99% compared to around 95%). The minimal losses in the Flexspline are transmitted to the system over a large area (the Flexspline is the largest element in the gearbox). As you correctly state, the losses lead to heat generation. This energy is radiated from the Flexspline surface or transmitted to the lubrication, which also has the task to remove this heat (as well as lubricating the gears). Further, the stresses in the Flexspline are always lower than the endurance limit so that a fatigue failure will not occur. This is a design limit of the gears. For the last point, good gear contact with a flexible gear, we have developed a special gear form for this motion. This is one of the “secrets” to the success of the Harmonic Drive® strain wave gears. So you can see that even with just three main components an Harmonic Drive® strain wave gear is a complex system with components designed expressly for the tasks required. For example, if there are 202 teeth on the circular spline and 200 on the flexspline, the reduction ratio is (200 − 202)/200 = −0.01 Thus the flexspline spins at 1/100 the speed of the wave generator plug and in the opposite direction. This allows different reduction ratios to be set without changing the mechanism's shape, increasing its weight, or adding stages. The range of possible gear ratios is limited by tooth size limits for a given configuration.

[@MasParaQue]

What the f....................... Im blown away

[@proto_hexagon5649]

to much friction. i prefer with bearing like this kzbin.info/www/bejne/haS2amB8r7CBbNU. But i dont know if can hold the torque because have bearing instead teth friction.

[@aadfuad3213]

Berapa harganya

[@cristianarango1509]

benn reading the comments of several videos related to new transmission drives, i supprised this is not full of peopple saying this is shit and doesnt work on cars

[@HarmonicDriveSE]

Dear cristian arango, The strain wave gears produced by the Harmonic Drive Group are an established gear principle. The basic principle was invented in 1955 and since 1970 the strain wave gears are produced under industrial conditions. So basically the gear principle is no new technology but already has a long heritage in industrial applications. The typical applications of strain wave gears are industrial applications, e.g. as joint axes in robots, in machine tools, medical technology, optical machines, aerospace etc.. In most of these applications the gears are used for positioning applications with focus on precise positioning, high dynamic acceleration and deceleration and long endurance qualities. So this gear type is no typical car transmission gear, which is rather dominated by spur gears or planetary gears. Best regards, Harmonic Drive AG Product Management

[@cristianarango1509]

thanks for the kind and detailed response, harmonic drives are quite effective in robotics and other applications, i was just complaining on how many viewers that are interested in transmission seem to think that the only possible application for a transmission is automotive drive

[@peteacher52]

Get rid of the distracting and annoying music.

[@wizardworld420]

get fucked normie

[@DarwinsChihuahua]

Fewer

I would suspect that this level of gear reduction would not serve much purpose in the automotive industry

[@AlxM96]

I suppose not, but this level of precision, minimal backlash, and low gear reduction can be invaluable in the robotic industry

[@samchan5251]

@@AlxM96 Camera focusing as well.

[@irrelevantfish1978]

While unsuitable for vehicle drivetrains, harmonic drives could be useful in reducing the size/weight of other motorized assemblies, like those powering windshield wipers or electric power steering. The benefits would probably be grossly outweighed by the cost, though, so Matteo Allesandro is correct that the primary market is in automation. Harmonic drives' ability to achieve zero backlash while retaining a long service life is a godsend for precision CNC rotary tables, for example.

[@rmsrmsrmsrms]

You’d be wrong, as these drives were integral components of all the Apollo Lunar Rovers