I actually just wanted to do the drawing, but once the drawing was done I figured since I had come that far, I might as well explain the darn thing too. =)

I published my bevel gear sketch once with an explanation, and once just as the drawing. Thats something I can think about in the future.

youtube.com/@thaaiveeduchannel

​@@INTEGRALPHYSICS Could you please share the tool you use for strength calculation, particularly for globoidal gears

It's a super clean draft

Thanks!

Thanks! It was fun to do.

best drawing ive seen

Thanks.

Torque is the goal with a worm gear.

Whether the worm assembly is self-locking depends of the pressure angle between the worm and wheel, or if the worm has a double start thread...

I was going to make this important point as well - but checked and see you have it covered. This locking feature is what makes it a perfect design for a tuning gear on a guitar for example- not only the gear reduction.

You are absolutely correct. No part of the worm ever moves axially.

youtube.com/@thaaiveeduchannel

Glad it was helpful!

Thanks! Glad you enjoy it.

Big wheel + Small Pitch = Big Torque If the pitch of the worm is large enough the wheel can in fact turn the worm.

thanks

Thanks!

Thanks!

You are absolutely correct. I thought I would save that for another video. This one was just meant to be a very basic intro.

Glad you liked it!

Glad it helped

@@INTEGRALPHYSICS Yes it is bro. Here i did it. kzfaq.info/get/bejne/jpyPbLOFr7XRm2Q.html

I like the idea but at first glance there may be a problem. The issue being that the worm wheel can not (typically) drive the worm. So if you are using something like a circular saw, the moment you let up off the trigger, the motor stops, but the blade would not... and the inertia of the blade would tear the gears apart.

You are absolutely correct. Good eye. Thanks!

Glad it was helpful!

So far we agree 100% =)

Welcome

No, I have not.

Worm bike. I like that. Is it going to be a shaft drive?

There is definitely energy loss, whether or not you need to worry about it depends on the application. One thing to keep in mind though, is that energy loss will NOT affect the gear ratio, only the actual mechanical advantage.

Its a good idea, but unless you change the actual tooth count on the wormwheel, the GR will not change.

@@INTEGRALPHYSICS I don't quite know how to describe this, but if a normal rotation of the worm would move one tooth of the wheel, couldn't it be adjusted so half a rotation would move one tooth?

Yes, you could have two threads on the worm rather than a single thread.

The point of the worm gear is to provide an increase in torque. Using a worm gear, a low torque motor can be used to produce high torque on an output shaft.

okay.. like how & what is this thing which make this transition happened!?

Recommend that you take a look at a modern spinning reel schematic.. this is the exact case use in real life.. the worm wheel (handle) is used to turn a pinion gear (which is what drives the rotor) which lays the line The point of using this great mechanical advantage is that it can still drive the rotor even under heavy load (the fish pulling) which is torque I believe Google spinning reel schematic (stella, saltiga, exist, Certate) all model names 👍🏻

If you prevent the worm gear from rotating and then drive the wheel as the input you effectively have a rack and pinion.

Typically no. Once friction is factored in, it is extremely inefficient (or even impossible) for the wheel to drive the worm.

Im not sure of the application, but all other conditions being the same, changing gear ratio like that is likely to overload the motor. Additionally a 10t worm wheel is going to be VERY difficult to design to run smoothly.

Thanks!

Welcome!

Yes but... When you factor friction into things, I suggest you consider a bevel gear. You can produce the low gear ratio you desire and easily build in the perpendicular relationship between the crank spindle and the prop shaft. Hope my suggestion helps, let me know how it goes and good luck!

I suggest you determine the desired gear ratio. Then, provided you know the desired output torque, find the gear tooth size that will support the needed torque (theoretically this is based on the shear strength of the material as well as tooth profile, gear lash, tolerances and width). In reality, find an existing worm gear design that is rated to a certain load for a given material, use that design.

Under normal circumstances if you drive the wheel it will not turn the worm. However if you allow the worm to move translationally, what you essentially have is a rack and pinon.

@@INTEGRALPHYSICS thank you very much

I should say that I meant rotational movement, and not translational

Rotational Movement: not going to happen unless the pitch of the worm is INCREDIBLY LARGE.... But it is possible.

The drawback of a worm gear is that the wheel can not drive the worm. It sounds like you probably need a clutch between the gearbox and the wheels.

@@INTEGRALPHYSICS Thx 4 ur immediate reply. There was a man from Japan who was able to do that on his 0-scale - 2 rail locos. But lost touch w him. I don't think he used a clutch (to disengage the spur gear from the worm). But perhaps, i may need to look into this clutch deal.

Indeed. I thought that may be to complicated for a worm intro, but you are absolutely correct.

Short Answer: Gear lash = wiggle room between gears Longer Answer: In reality the line of action between gears is not tangent to the base circle of a gear. As a result the gears are not moving PRECISELY at angular velocities given by GR=Win/Wout. To put it another way... If the input shaft turns at constant velocity, the output shaft is going to speed up and slow down just a little bit with every tooth. Gear lash can affect how rapidly that speeding up and slowing down occurs.

change the center distance for difference backlash, Am i right?

@@user-pe5yy1yo2v Yes.

Most worm gear systems are specifically designed so you can't drive it in reverse. An application of the worm gear, is the tuning knobs on a musical instrument, which allow you to tighten the string, but don't allow the string to unwind the tuning knob. It is possible with an extremely steep helix of the worm threads, to make a worm gear that can be driven by the worm wheel, but it is rare that we desire such an application. It is much more likely that we would use other gear arrangements if we wanted bidirectional power transmission.

Short answer: its 40x the input torque. Longer answer: you are going to need to know the frictional losses along with the worm pitch and tooth profile to factor in losses and inefficiencies.

@@INTEGRALPHYSICS Worm gears aren't anything close to 100% efficiency. Spur gears in the limit of perfection can be 100% efficient, and in practice tend to be 98% efficient. Worm gears are inherently inefficient and are limited by the kinetic friction coefficients of the materials we can use. For a worm gear, 50% efficiency is optimistic, and is typical of what you can expect from the best worm gears available. A worm gear not built specifically for efficiency, will likely have an efficiency around 25%.

Thanks

no, pero volveré a dibujar el engranaje pronto para un video sobre engranajes hipoides.

@@INTEGRALPHYSICS ojalá pronto

there's a song 2 reference here...

you want to machine one? as far as I know it's one of the hardest to machine gears so good luck :D what you should do is just check classified ads, or scrap yards in your area, some snowblowers use worm gears in the differential. some cars do too. save yourself the headaches.

@@chrishayes5755 yeah but the thing is tiny, and my class ha s although axis, we have plenty of tools and I only need to design it

It's supposed to be 8mm Dia and 24 mm long those are the maximum dimensions...

I try to keep these sorts of videos very general because, as you are seeing, things become very specific very quick. My suggestion is start at your desired gear ratio and work backwards from there. The distance between the shafts is the effective sum of the worm and worm wheel radii (to the line of action). Tooth profile and pitch are dictated by load, shaft speed, shaft stiffness, motor torque, gear hardness, surface finish, service life etc. I assume you are trying to 3d print these parts. Worm gears are based on slippage, they are effectively inclined planes, so think about your print orientation. I suggest you print the worm gear on its end so that the layers are mostly in the direction of slip. The wheel can be printed laying on its face. Its not perfect but at least that way the edges of the layers will be perpendicular to each other along the line of action which should smooth the action of the gear set. If 3d printing, I suggest you coat the parts or sand them smooth between the teeth. If you are going to turn or cnc these parts I suggest you pull gears from something like Autodesk Inventor which already has gears designed in the catalog.

@@INTEGRALPHYSICS Thankyou, we have a 4th axis in class in one of our Haas machines, and im thinking about making the gear in there, I'm trying to use everything from a Bondtech Bmg extruder, except I designed a new case, heatsink and now working on the worm gear problem. It's going to be really small so printing won't work great

Thank you.