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Home > Ideas > 4-speed Sequential Transmission With Stepper Shifter

4-speed Sequential Transmission With Stepper Shifter

August 20th, 2016 Leave a comment Go to comments

1A 4-speed sequential transmission with comfortable remote control mechanism. Instructions available.
This design is a development of my earlier 4-speed compact sequential transmission which could be shifted remotely using just a single motor. The problem with the older design is that shifting was slow and required some precision, and because of it it was not possible to shift while driving. This design uses a stepper mechanism to solve all these problems.

Just like the older version, this transmission can be shifted by any motor, in any direction, and in full cycle – from 1st speed to 4th and back to 1st – but when shifted by a PF M motor, it’s fast enough to shift while driving, without stopping. Additionally, it’s easier to control because one rotation of the shifting motor changes speed by one and you can hear every rotation. The older design can still be useful when precision and fast shifting are less important and when its smaller size can be an advantage.

Just like before, the input and output shafts go through the whole transmission, so they can be connected from the front or back of the gearbox – or even from both sides e.g. if you need to drive two axles, with transmission located between them. The transmission is also braced with studless frames and can handle plenty of torque, and it’s highly effective. This is because the higher the gear, the fewer active gear wheels are being used, which allows a single PF M motor to run this transmission on 4th speed without much strain. The gear ratios produced by the transmission range from 5:1 reduction at 1st speed to 1:1 at 4th speed. It was designed specifically for gearing down – first three speeds gear the driving motor by varying degrees and the highest speed offers unchanged gear ratio.

This is the best transmission I’ve designed up to date and I hope it will see a lot of use, and not just from me.

Free building instructions for the transmission and for the stepper mechanism alone are available in the Downloads section.

The stepper mechanism alone:

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  1. sohibil
    October 16th, 2016 at 19:53 | #1

    @Sariel
    I accidentally found the gear on BL. It’s written there it was first released sometimes in 2012.

    Now that i look at it, it doesn’t seem too useful.

  2. Sariel
    October 16th, 2016 at 18:15 | #2

    @sohibil
    It’s been released a year or two ago.

  3. sohibil
    October 16th, 2016 at 17:53 | #3

    I noticed some new (to me) gear in there. It’s located right next to the shifting motor and has yellow liftarms attached to it. Was it just recently released?

  4. Sariel
    September 16th, 2016 at 00:23 | #4
  5. Josh McLaughlin
    September 15th, 2016 at 22:28 | #5

    Hi I love this gear box so much I found a channel that is also making gear boxes and wondered if you had found it yet https://www.youtube.com/channel/UCr3J0-FX8W77KhHTHGJ97hQ

  6. Sariel
    August 24th, 2016 at 20:58 | #6

    @kremlingrasso
    This particular piece is also found in the official Technic sets (e.g. 42053), so I don’t see any problem here.

  7. kremlingrasso
    August 24th, 2016 at 19:16 | #7

    is using Hero Factory parts a lesser or greater sin then using Bionicle parts combined with Technic?

  8. Stewart
    August 22nd, 2016 at 06:55 | #8

    @Sariel
    FYI, there is a typo in the instructions. In the parts list, there is one listed as 34x, it should be 3x.

  9. Sariel
  10. Stewart
    August 21st, 2016 at 03:36 | #10

    What is the circular part used to connect the two drive rings to each other at a 90 degree phase?

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