Differential Causing Gear Ratio Increasement? + Drivetrain Clicking

[agrof]

Looks like a good solution!  If it still fits into the chassis, than perfect.

[StudWorks]

@Didumos69 and @agrof I finished rebuilding the rear axle. Here are some pictures:

Before

After

My finger points to where the 24t gear is now.

The axle has room in the front now without the gears being in the way and everything is much smoother. Very excited for whatever result I get when I put this in the chassis.

I'm curious about the knob gears I am using to transmit power from the motors to the gearbox, are these the best gears for the job?

[Didumos69]

10 hours ago, StudWorks said:

My finger points to where the 24t gear is now.

The axle has room in the front now without the gears being in the way and everything is much smoother. Very excited for whatever result I get when I put this in the chassis.

The willingness to refactor in order to solve seemingly minor issues is what Technic design is all about , imo!

The knob wheels won't slip, but do generate more friction, especially under higher torque. (EDIT: The knobs rub while turning. The more torque, the more friction this rubbing suffers from.) You could try with 2 12t gears first. The way they are enclosed in a 5x7 frame should be enough to avoid slipping. In fact 2 12t gears are less likely to slip than 2 thin 12t gears or 2 thin 20t gears, as long as they are braced well. Flatter gears bend more easily.

Edited October 30, 2019 by Didumos69

[agrof]

 Glad to see the result, Your willingness inspires me too... I am digging out my unfinished MOCs now. 

[StudWorks]

9 hours ago, Didumos69 said:

The willingness to refactor in order to solve seemingly minor issues is what Technic design is all about , imo!

The knob wheels won't slip, but do generate more friction, especially under higher torque. (EDIT: The knobs rub while turning. The more torque, the more friction this rubbing suffers from.) You could try with 2 12t gears first. The way they are enclosed in a 5x7 frame should be enough to avoid slipping. In fact 2 12t gears are less likely to slip than 2 thin 12t gears or 2 thin 20t gears, as long as they are braced well. Flatter gears bend more easily.

Thank you. Do you think I should I replace the knob gears or not? I like them the way they currently are.

Fun fact: A year ago when I was building this car it used to have the chassis from your modified Porsche 911 GT3 RS with the tilted steering wheel and everything. It was too out of scale with the car I'm trying to build so I built something else.

9 hours ago, agrof said:

 Glad to see the result, Your willingness inspires me too... I am digging out my unfinished MOCs now. 

That makes me happy. I have been through that before and inspiration from other goes a long way. I was working on this car for almost two years and now I'm very happy with the progress. Would enjoy seeing your MOC progress in the near future!

[Didumos69]

2 minutes ago, StudWorks said:

Thank you. Do you think I should I replace the knob gears or not?

Yes, I think you should.

[StudWorks]

1 hour ago, Didumos69 said:

Yes, I think you should.

I replaced the knob gears with black 12t gears and tested the car. The gear slip kicked in as the driven 12t gear moved but the one connected to the gearbox didn’t. Thanks for the idea, but it didn’t seem to work in this situation. I am going to swap in the knob gears and try again.  I will let you know how that goes.

[StudWorks]

20 minutes ago, StudWorks said:

I replaced the knob gears with black 12t gears and tested the car. The gear slip kicked in as the driven 12t gear moved but the one connected to the gearbox didn’t. Thanks for the idea, but it didn’t seem to work in this situation. I am going to swap in the knob gears and try again.  I will let you know how that goes.

@Didumos69 I tried it with the knob gears know and I still hear clicking. I can't find where the gear skipping is but I believe it's with the 24t and 8t gears because I normally can't see them with the reinforcements in.

What do you think is the problem?

Edited October 30, 2019 by StudWorks

[Didumos69]

13 hours ago, StudWorks said:

I replaced the knob gears with black 12t gears and tested the car. The gear slip kicked in as the driven 12t gear moved but the one connected to the gearbox didn’t. Thanks for the idea, but it didn’t seem to work in this situation. I am going to swap in the knob gears and try again.  I will let you know how that goes.

Okay. If it had been okay with 12t gears, that would have been the better option. But since it's not, you're right to fall back on knob wheels.

12 hours ago, StudWorks said:

@Didumos69 I tried it with the knob gears know and I still hear clicking. I can't find where the gear skipping is but I believe it's with the 24t and 8t gears because I normally can't see them with the reinforcements in.

What do you think is the problem?

Apparently something is causing substantial friction, otherwise gears would not slip. Your gearbox uses clutch gears as intermediate gears to pass drive from the engaged clutch gear to the output. Even though many others do that, I can guarantee it's not a good idea and will induce friction. But maybe that is not the biggest cause. To find out the friction source, I always put in torque manually up to the point where the drive train almost starts moving. At this point I check wit my other hand all axles involved to feel if they are stressed in some way. An axle that is not stressed, will still slide and move a little when you touch it, but axles that are stressed feel as if something has a grip on them. The stressed axle is likely the axle that suffers from friction directly.

Edited October 31, 2019 by Didumos69

[StudWorks]

On 10/31/2019 at 4:07 AM, Didumos69 said:

Apparently something is causing substantial friction, otherwise gears would not slip. Your gearbox uses clutch gears as intermediate gears to pass drive from the engaged clutch gear to the output. Even though many others do that, I can guarantee it's not a good idea and will induce friction. But maybe that is not the biggest cause. To find out the friction source, I always put in torque manually up to the point where the drive train almost starts moving. At this point I check wit my other hand all axles involved to feel if they are stressed in some way. An axle that is not stressed, will still slide and move a little when you touch it, but axles that are stressed feel as if something has a grip on them. The stressed axle is likely the axle that suffers from friction directly.

@Didumos69 That's very interesting... one thing I wanted to point out was that in 4th gear the 4-speed gearbox has a 1:1 ratio. It's a lot of force to move the car at the same speed as the two EV3 large motors themselves, especially with the huge wheels from the Porsche 911 GT3 RS. I think I should make a gear reduction somewhere in the car with a 12t gear driving a 20t gear.

Here's a picture where I point at a 4L axle with stop. This piece tends to slowly pull itself out during the slipping.

Edited November 5, 2019 by StudWorks