2 speed transmission idea
 

ive been thinking of how to have a 2 speed transmission and figured to do so youd need to get two new gears (one metal and one plastic) at the proper ratios, then mount them on a sliding axel with about 2cm space in between, youd also need a thin pinion gear on the motor so only one gear touches at a time, about 1.5cm, have them in the normal position and they would move with two magenets, for the first gear a magnet would pull the metal gear pulling the plastic gear to the motor, and for second gear the magnet would repel the metal pushing it to the motor, and sliding the plastic gear behind the pinion (between the can and pinion)... its farfetched i know but its an idea to sit on.

btw the magnet i speak of would be near the differential in that area

When I was a kid many,many, many years ago I made a two speed transmission for a toy rc car. I never got it to work completely so I forgot about the project. As I got older I realized that an electric car would need a transmission for a different reason than a gas powered car. An electric motor produces maximum torque at or near zero rpms. A gas motor usually produces peak torque somewhere within 60-100% of peak rpms. Good luck if you continue to pursue the project. BTW it would have to be an automatic transmission because there would be no way to shift gears remotely with the xmods 2 channel transmitter.

but you could have it manual, take a spare zz or bit or buy a clone, extend the range as much as possible and set it that foward gives an electromagnet juice and backwards gives it opposite polarity... i suscribed at some site for a free xmod, if i get it ill use as an experamentee for fets and ect...

yeah i had that electromagnet idea a while ago but there's just not enough juice in it to pull the gears in to synch up... best to get a hardwired motor off of a clone and use that, hopefully i'll have a redesign ready or a prototype ready soon... haven't worked on it in a while now....this will be interesting

why not remount the Hi Lo trim button?

Why not build a spinning clutch, I.E., when the motor spins faster, the gears move outward, switching gears. A CVT would be way cooler though.

Well if Bits or Micro RC car (1/64th scale) cars have 2 speed's or a boost function, why couldn't an Xmod. There pretty much the same just at a different scale.

ok I understand, so do zipzap SE's have ESC?

Why not have the magnets be powered by your motor wires? the more power (speed) the more the magnets attract the gear, to switch them, then less power (force) and it repels the gear, switching back to first

find any rc cars two speed gearset and tear it apart and figure out how it works then build one that will fit an xmod.

It could be done just go to HPIracing.com and look for the 2speed trans for electric cars in the instruction area.You will see a simple clutch setup in the picture.

hpi

yeah, hpi makes some of the best automatic 2 gear transmissions out there for RC Cars

here's a picture from hpi:

Somehow I don't think that tranny will fit.

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there are loads of problems with this idea:

1. first off it would benifit the car none

2. to actually build and two speed tranny that would fit would be a humongous task. Have you looked at the xmod chassis? its quite cramped.

3. someone brought up the point that since a bit or bit clone has two speeds why cant an xmod? to answer that question the bits "second speed" is done with electronics not mechanical parts. All is does is boost the power to the motor. The xmod already has this in its hi lo switch.

lol id have to agree that it would b hard but it would b great for performance, you could have one gear to get u goin and another for top speed...

i got an idea for a clutch, it would only work for rwd cars tho, what u do is sand paper on washers, and put the washers on the diff with a spring pushing them apart, then use a magenet to pull the metal washers ans sand paper together, this is hard cause ud need a powerful yet small magnet, and a way to disengage and engage this magnet... if you were gifted you could figure out a way to set it up so that if u double tap the throttle and floor it is disengages the clutch for 3 sec and drops it, talk about killa burnouts

alas this isnt posible and as usualy i will receive my fair share of hate from this site just cause of a yet cool idea... jeeshe

2 speeds arent needed for an electric car the only thing its going to do is add weight. an electric motor makes all its tourqe and power at any rpm. they dont need a lower gear to get them rolling like an internal combustion engine. if you want to go faster just add more gear and motor RPM

lol ok its not like im building this or anything, heck my car aint even put togetehr yet... havent drivien the poor thing since last march

yeah micro kid is right electric motors have no power curve like internal combustion. almost all the torque comes at almost no rpms. they only thing i could see you needing this for is if you had so much power that you couldnt get the car to full speed from a dead start because you tires spin. and the only way i could see this helping with that is adding weight to the back of the car.

Cool idea? yeah but worth wasting time on? dont think so

but on the other hand i guess if you just wanted something to do with your thumb while your driving your car you could make some kind of electric transmission. You could do it with like a pot on the controller tha has say 6 different settings. and when you turned it to the first setting the car would go a certain speed then when you went to the second it would go faster and so on. But all this would really do would be replace the throttle

The E-maxx has a 2 speed transmission and its electric :rolleyes:

I think youll benefit from it if you made a monster truck xmod with a high and a low gear :D .

Comparing an emaxx to a xmod is crazy. First off theirs an obvious size difference. The emaxx uses its tranny so it can get off the line faster without spinning its tires. With something as small as an xmod (that basically has hard rubber tires) you dont have this problem because of the weight and the fact that the tires dont give when you accelerate.

second the emaxx has power way beyond anything an xmod could ever dream of in torque. Without the two speed it would probably wheelie all the time.

what ever :D !!!

:cool:

Wait, wait, wait.... so this HAS been done? We need more info!!!!

No :(

That should be pretty fast.:D

obviously some morons here cant see that the picture has 2 motors in it, not 2 speeds duh [slap]

Well, the design was to have 2 different RPM motors, the slower one would take up the lower range, then it'd flick off and the upper would take over.

and how would you do that? You'd need 2 ESCs not to mention a custom made circuit That weight would probably just make it the same speed as a stock xmod

That was the problem.

just about anything you make that actually works would weight to much and just slow it down.

Hmm, ok, so what is that setup used in? You should build a mini e-maxx! :chuckles:

yes, but this mod would slow it down so much it would be the same speed as stock

Its funny to say this setup will probably slow the car down obviously yall dont know the power of these little motors just one by itself can do the job they possess the same ability as a brushless motor .I might have to add more weight to keep the tires on the ground, so weight is the least of my worries haha :D .

i think you are being way to ambitious. I mean hey theres nothing we can do to stop you from screwing up your xmod and wasting your time on whatever you want but if you stop to think about it IF you can actually get a two speed in a car this small (and thats a very big if) it wont help it anyway.

The only way it would help is if you, for some reason, wanted to start your car off slow and then gradually get faster. Because electric motors have all their torque and speed at 0 rpms and since the have no power curve all you would be doing is slowing it down. And as for the emaxx having one it is much much larger than an xmod and has much more powerful motors that need a two speed to keep the tires from spinning.

Also another thing that contributes to tires spinning on the emaxx is that they are pneumatic. The tire can flex and twist on the rim. With an xmod the tire is a round piece of rubber on a plastic rim with no space between. Getting a tire like this to spin would require a pretty large around of force unless of course you were on a surface that its not designed for (sand, loose dirt, stuff like that)

and i agree that two of those motors on a car that small given the right power supply would probably give some pretty nice speed but now since they are higher up it will raise the COG and arent you planning to only run one at once? like a slower one first then switch to the second one?

hahahaha Ive already achieved what I wanted to do dual motor xmod ,now a 2-speed trans is possible just because you dont have the know-hows doesnt mean no one else does. oh yeah these are the wheels Im using.

I will be running both motor at the same time.

The purpose of a 2-speed trans will be low gear and high gear the 1 gear will be for when you need high torque for climbing and 2 gear is for top end speed .how can you say 2-speed wouldnt serve no purpose?

wow those people saying a 2-speed tranny wouldn't work on these electric motor because they produce max tourque at 0 rpms are very wrong. Unfortunately you are forgetting one thing, the two speed tranny would change the gear ratios not the tuorque of the motor. If you think about it the gears are the difference from the drift to the top speed motor. Therefore if you start out with the torque of the white gear and can switch to the top speed gear you have a successful 2-speed tranny that would work with the "electric motor with max torque at 0 rpms"

And you still disagree with me go read up on a little thing called mechanical advatage.......

"You can't argue with science!"

i agree. the low gear gives the car acceleration, the top gear would take over when the lower can't make the car go any faster. so the car in low gear takes off the line like a shot, then the high gear gets it to top speed. it's like bits or zz's those crazy 4:1 ratios can hardly move the car, even at near 0 rpms, but give it a push and the car will eventually get to some insane speeds.

this mod would definately help, but only if the gear ratio you want to use is so high that the car can't move itself from stop.