high strength shaft pinion gears, chain sprockets and motor adapters

I was wondering if there will new 12 tooth pinion gears that will fit on the new shafts and adapters for motors so you directly drive a high strength shaft from the motor because we thought these would be good for lifts but it doesn’t look we can’t use them without using the old shafts. And we can’t compound gears ratios with the pinion gears because they don’t fit on the new high strength shafts. Also wondered if there will new chain sprockets that will fit on the new shafts since the don’t use the metal inserts like the high strength gears.

We asked this at worlds this year and their response was to be imaginative, but I don’t think that any adaptors will be available, this season at least.

Hopefully these answer your first question.

How thin is that metal? It looks like around 2-4mm.

I was thinking about that but would it make the gear a lot weaker. The material looks so thin.

The gear would basically break really easily. It’s not supposed to fit (Jordan was trying to show that the 12-tooth gear with the .25" hole in the middle would be impractical).

You really shouldn’t need to use high strength shafts unless you’re compounding gears or something of that sort. Like the VEX website says, they’re useful for high torque applications, and usually the only time you need shafts this thick is when you have a really high gear ratio, which can only come from compounding gears.

All high strength VEX gears should fit on the shafts except for the 12-tooth gear.

Not all of the gears fit on the new shafts because the last time I checked the high strength 12 tooth pinion gears did not fit on the new shafts. Therefore, you can not effectively use these new shafts to make high torque compound gear ratios for lifts. some examples are 1:9, 1:15, 1:21, 1:25, 1:35, 1:49. you can not do it because the ratio requires 2 of those pinion gears. So then you have to use the old shafts on the first stage and use the new shaft on the last gear. And there’s no point of doing that because you would mount whatever you’re lifting directly onto the gear and that itself takes a lot of the load off of the old shafts. Plus there’s no adapter that you can use to make the new shafts to be driven directly from the motor, so then you have to use the old shafts. I just don’t understand the point of these new shafts if they don’t provide these things. I can kind of see how you would use it in a drivetrain since they posted a picture explaining how to use the bearings, but again you have to use the old shafts the drive new ones and that is a serious weak point.

Assuming you even need the .25" shaft to be driven (which you shouldn’t), even if you have a special coupler for the shafts, the .5" shaft that connects the coupler to the motor will just bend. Again, you shouldn’t need the .25" shaft to be driven.

I was thinking the adapter would be one whole piece, not like how the current coupler works or maybe they could make a new output gear for motor though that would be a bit more complicated.

But using the old .125 shaft would make that part the weakest point in the whole assembly. We’ve had motors twist and break the old shafts.

I highly doubt that the actual motors have twisted and broken the .125" shafts. They don’t output enough torque to accomplish this. More likely though, is that you’ve had shafts twist and break in high torque gear trains. We’ve had this happen multiple times before. That is why the new .25" shafts are compatible with the HS Gears.

Yes, this is what I was trying to say (in really bad wording, though, thanks Longarmx for making it more clear).

there was one time when I was a student in this program we were prototyping 8 motor drives. we had 4 motors geared together to one output shaft and that twisted and broke the shaft. the output shaft was geared for high speed and the ratio was .3:1. This was when the 393 motors were new and we didn’t know about the 4 motor limit. We were doing pushing contests as well.

And again they don’t fit all of the HS gears

Yes, 4 motors geared to one shaft is a high torque gear train. The shafts directly connected to the motors were not the ones that twisted. The only place you would’ve needed a high strength shaft would’ve been the output shaft that had to bear the torque of all 4 motors.

I guess we just have different definitions of what is a high torque gear train is. What I think is a high torque gear train is something that I can’t stop with using my hand.

Yes I know that but in order to do that I would have to add an output gear that fits the HS shaft. That would make a bit more complex because then you have to build a gearbox for that. It would also mean the same thing for lifts. It would be simpler to be able to drive the shaft directly from the motor.

It is high-torque relative to the torque of the motor.

I don’t understand why you need another output gear in order to use the larger shafts. The shaft the motor is driving doesn’t need to be high-strength because a motor doesn’t have enough torque to twist it. The other shafts in a gear train that increases torque can be high-strength because wheels and high-strength gears larger than 12 teeth can use high-strength shafts. If you’re direct-driving your lift with no gears at all… don’t.

Well how are you gonna transfer the power from the motors on your first stage in your gear train? Especially if you are doing a reduction on a lift or something.

I simply don’t care if the motors specs say it won’t twist the old shafts. I would like to be able to use the new shafts on everything because they are “high strength”. And in the beginning I only wanted to know if they were plans to be able to directly drive them.

And since when did I say if I was direct driving lifts? I’ve been talking about directly driving the new shafts with gears on them the entire time.

If you dismantle a motor you’ll figure out pretty quickly there just isn’t space to fit a 1/4" shaft because the output gear diameter simply isn’t large enough and you’d need to create an entirely new gear set if it was even achievable. Next problem is the internal gear material is too weak to make it worth bothering with. Teams can destroy the gears with 1/8" shafts so you already know the weakest point. It’s a little motor and little motors only need little shafts - engineers don’t usually over spec things unless there’s a really good reason.

Probably the best you could ever hope for would be a 1/8" to 1/4" shaft coupler but as others have already pointed out there’s really no justification from a torque perspective so don’t hold your breath.

Have you read my earlier posts? because I have said that they could make a new internal gear kit. But I thought it would be a bit complicated because it doesn’t look like there’s enough space inbetween the mounting point of the motor and the output. Just now I thought maybe they could bring back the vexplorer motors (http://www.vexrobotics.com/wiki/VEXplorer_Motor) since its bigger, and slightly modify them for more torque and to fit the new shafts. Though I only worked with them in botball one year and they seem to be pretty solid.

Putting a 1/4" shaft into the existing 393 motor design is a no go for multiple reasons. I’d much rather see something like a “939” motor with 1/4" shaft but that would require a special motor driver too and as it is many VEX parts can be pushed to the limit already so adding yet more torque is just going to break something else. 1/8" shafts actually provide a nice “limiter” in this robotics system IMO.

That motor would be the modified vexplorer motor I mentioned, if that ever happens.

Why would it need a special motor controller if it would be using the same motors from the 393s? the only difference would be the gear set.

And yet they provided new shafts to handle higher loads. and again I’m still curious if they’re gonna make something that will drive the new shafts directly.