[POC] Sequential 8-speed transmission tunnel

[Didumos69]

After @Seasider asked whether the new gearbox parts would allow for a transmission tunnel, the idea sticked with me. So I started designing my first 8-speed gearbox, or in fact 8-speed transmission tunnel. All axles, including the control axles are aligned in a 3x3 tunnel. It has 90-degree limiters for all control axles and a 8<->1 gearblock. Clutch gears are only used for engaging with driving rings, not for transferring drive over axles running at different speed. I think the end result is something special. I used 16t gears to pass control from the main control axle to the secundary control axle. Theoratically knob wheels would have been better, but in practice the 16t gears operate much more smooth and the 90-degree alignment of the control axles is still good.

LXF-file here.

Spoiler

Original media:

Edited July 2, 2018 by Didumos69

[jorgeopesi]

And it seems that you can hit someone with this, small and strong  .

[Aventador2004]

Very cool and compact. Everything looks well made.

[1963maniac]

Thanks for building and posting this. This is a real beauty!! Pretty small too!! Any information on gear ratios? Does it have reverse? Where do the o-rings go? I plan on building this next.

[Lox Lego]

Brilliant! Fantastic design in an unconventional central tube. Not sure how you figure this stuff out! Look forward to trying your Bugatti gear box with the B-Model. Keep it up @Didumos69!!!

[suffocation]

This is terrific! Thank you for sharing

[Didumos69]

Thanks guys!

On 6/30/2018 at 10:48 PM, 1963maniac said:

Thanks for building and posting this. This is a real beauty!! Pretty small too!! Any information on gear ratios? Does it have reverse? Where do the o-rings go? I plan on building this next.

It has no reverse and the white silicon bands are wrapped around the red 2L axles and the pins with towbal. The ratios of the primary gearbox are: 1:1, 5:4, 5:3, 25:12 and the ratios of the secondary (low-high) gearbox are: 1:1, 25:9. Together that makes: 1:1, 5:4, 5:3, 25:12, 25:9, 125:36, 125:27, 625:108, or 1, 1.25, 1.67, 2.08, 2.78, 3.47, 4.63 and 5.79.

Btw, I think I might be able to squeeze it 2 studs shorter.

Edited July 1, 2018 by Didumos69

[Seasider]

Looks great @Didumos69 I’m glad I now posted the challenge

[Didumos69]

The 2 studs shorter version works equally smooth, if not more smooth:

LXF-file here.

[1963maniac]

Are the gear ratios of the short version the same as the original LEGO Technic - Sequential 8-speed transmission tunnel with rotary catches II ? 

[Didumos69]

8 minutes ago, 1963maniac said:

Are the gear ratios of the short version the same as the original

Yes they are the same. The in out ratios can be changed though. The primary gearbox and the secondary gearbox are connected with a 16-16 gear mesh in the center of the gearbox. This could be changed to a 20-12 or 12-20 mesh, which would multiply all speed ratios by 20:12 or 12:20 respectively.

Edited July 5, 2018 by Didumos69

[BusterHaus]

Wow, I missed this post until today. Very nice work,especially on the gear ratios. They have a nice progression to them. 

One thing that I've been wondering about since the Hammerhead shifter is the durability of the silicon bands. Do they keep the same elasticity for a long time? I really like @Paul Boratko's solution with a shock absorber, and I've also built shifters with torsion axle locks, so I wonder how they compare. 

[Didumos69]

14 hours ago, BusterHaus said:

ne thing that I've been wondering about since the Hammerhead shifter is the durability of the silicon bands. Do they keep the same elasticity for a long time?

I have my Hammerhead still assembled and both the return-to-center for the shift lever and the 90-degree limiter of the shifter still work fine. Also, my experience is that these silicon bands last for many years. When I first got out of my dark age, my kids received some boxes with LEGO from family. There were several white silicon bands in them that are at least 10 years old and they're still in perfect shape.