What's the correct denotion of a typical lego gearbox? ("synch

[Kumbbl]

Hi,

after thinking a little bit about the realism of typical current lego gearboxes, ie. based on any combination of drivingrings and clutchgears (and regardless if sequential or not, becaue this doesn't matter), i came to the result, that "synchronized gearbox" (as often read here in many threads) is false, at least misleading, because:

- In a real transmission gearbox the term "synchronized" means that the input and the output shaft are equalized in speed for the short time of the shifting action so the "dog clutch" (in lego this would be the drivingring) can catch the gear without any noise...this is typically achieved with so called "synchronizing-rings"

- a typical current lego gearbox doesn't (and can not) equalize speed of input and output shafts for the shifting action cause of the lack of such synchronizing-rings

So IMHO the denotion "synchronized gearbox" for a lego gearbox is somehow false, what i'm searching for is a good name for a "gears-are-always-in-mesh"-gearbox - this is also the main difference (and advantage) to the previous "crash"-gearboxes...

Any thoughts rsp. ideas?

Best regards

[Bricktrain]

most Lego Technic gearboxes are dog boxes, though it is possible to have a crash gearbox with sliding gearsets. http://www.importtuner.com/tech/impp_1109_synchromesh_vs_dog_box/viewall.html

[Kumbbl]

ah, good explanation at this linked website - thank you for the link!

so the correct denotion of a current lego gearbox (as used in most of the supercars) would be "Dog box transmission" - right?

[Bzroom]

I agree, this denotion has confused me. I'm looking forward to more explanation. I always assumed that syncronized, in LEGO gear boxes without real syncro clutches, referred to the direction of flow of power. If it were syncronized, as you said, the gear engagement would be seamless. To me a LEGO syncronized transmission is one that is configured to have the clutch gears spinning at the proper speed for selection of that gear. In most cases I don't see how that's possible and I eagerly await a post from Sariel who used the term frequently in his book.

[Kumbbl]

IMHO with current lego parts a real synchronized (ie. input and output shaft are equalized in speed temporary just for the shifting action) transmission is impossible.. but i admit i'm not a "professional" builder as Sariel or some others here...

Edited March 31, 2013 by Kumbbl

[Lipko]

I guess it's called like "synchronized" in Lego, because the average people (like me) and kids only know terms "synchronized" and that "linear" thing (in Hungarian "push-gears" literally) transmission. Synchronized is very similar to this "dog box" thing, though the name itself points out the difference (I guess synchronized" is just an improved dog-box geqarbox). Since the term "synchronized" is widely known, it's okay IMO to call the Lego version like that too.

To me the characteristic difference was more about gears being always in contact and free spinning on the axle and clutches between the gears and the axle.

[Kumbbl]

Lipko, i can comprehend what you say - probably many people are similar minded concerning this topic - but it's also a fact that with current lego transmissions nothing is synchronized in the real meaning of this term - things are in mesh without any interruption - not more not less: some gears in mesh have nothing to do with synchronizing... at least in my opinion.

But on the other side it is probably also wise making things not to complicated - so when today the term "synchronzied" has been established for these (actually unsynchronized) dog box transmissions then there is no need to change this...

I'm just wondering so i opened this thread and question...

Edited March 31, 2013 by Kumbbl

[piterx]

in my Lancia im using this clutch i've done... it works both as a clutch and a freewheel (like on bikes)

it lets the wheels spin if the motor is not running....so you can switch gear safely...

and it also guarantees a smooth driving because the car is gonna keep running for inertia and won't be braked by the motor.

the only problem is that you need to have two more things if you use this: a R gear and a brake system :P

[Someonenamedjon]

What a coincidence! You mentioned a dog box, and your avatar is a dog!

[Blakbird]

You make a fair point. I use the term "synchronized gearbox" when comparing supercar transmissions on Technicopedia, even though I know that there is no mechanically or electro-servo controlled synchronization in place. I use the term to distinguish between transmissions that can be shifted while in motion and those that can't. On top of that, almost none of my readers would know what a "dog box" is, but it is perfectly accurate to say that this is how Technic transmissions actually operate. The inherent backlash in the dog stops allow the rings to engage while spinning as long as the shift happens quickly. Sheepo's sequential transmission is the best LEGO example of this I can think of.

[Bzroom]

I use the term to distinguish between transmissions that can be shifted while in motion and those that can't.

Please, can you refer to some examples of the difference here?

[Blakbird]

The transmission from 8860 can only be shifted by aligning the gears. Cannot be shifted while moving unless you get very lucky.

Conversely, the transmission from 8880 uses driving rings and can be shifted while rotating.