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Ari Holopainen / sequential | |
| R. Sequential Transmissions: Here are sequential gearboxes which use sliding axle technic. Also these have progressive gear steps when number of gears is 3-5. There are now available also truck and tractor transmissions in which both main gearbox and auxiliaries are sequential. You can also check Project 5590 which is motorized model team truck with 12-speed transmission that contains 3 sliding axle gearboxes. R.1. 4-speed, overall gear ratio 3,60:
This 4-speed sequential transmission has quite light progression while top step 3-4 is as large as 1,44 and step 1-2 only 1,67. So this could be used in diesel powered personal car. Design is double overdrive so it works best with low speed lego motor. It’s also lego builder friendly while there are no old 14 teeth thin bevel gears nor new 28 teeth double bevel gears.
This version is remake with two improvements: design is shorter while gear wheels take only 9 stud long space and ratio set is more realistic while underdrive top gear is changed to overdrive. Original design is moved to page Junkyard if you want to check it. R.2. 4-speed version II, overall gear ratio 4,08:
This 4-speed version II is wide ratio design so it could be taken from diesel powered personal car. Progression is stronger than in version I so 1st gear is slower giving better climbing and load carrying capability. This design contains one new 28 teeth double bevel gear which is named ML (medium large) in my notations.
Also this one is improved remake: new design is simpler without extra side axle, shorter while gear wheels take 9 stud long space and easier to shift while there is double bevel type gear in every gear pair. Original design is still available on page Junkyard if you want to check it. And as an interesting detail these 4-speed version I and II are modular designs with identical frames and gear wheel locating, only change is different gear wheels to get alternating ratio sets. R.3. 4-speed version III, overall gear ratio 3,43:
This 4-speed sequential is not very short but it’s quite narrow and flat because it uses only 8, 12, 14 and 16 teeth gears. While number of possible ratios is limited I had to use side axle to get suitable ratio for 1st gear. Although this small design ratios, (progressive) gear steps and overall gear ratio are very typical for 4-speed gearbox. Top gear is overdrive and there is no direct gear in this gearbox.
R.4. 4-speed version IV, overall gear ratio 3,18: Here is another quite small 4-speed sequential gearbox, 1 stud longer but even thinner than previous version III. Again it uses only 8, 12, 14 and 16 teeth gears and 1st gear has a side axle. Significant feature is that in 2 decimal accuracy this gearbox fits perfectly to the theory of progressive gear steps. (More info at Gearbox theories.) Now basic gear step is 1,36 and progression factor 1,08.
This is the first time I use 12 and 14 teeth gear pair in sliding axle solution. Normally I use them overlapped with same axle base as two 12 teeth gears. Now they are placed vertically so that there is one plate between bricks (0 LU;4 HU). I haven’t used this placement before. R.5. 5-speed, overall gear ratio 5,00: Despite what I earlier wrote about 5-speed sequential (too long), I decided to design one. Yes, it’s quite long for a single gearbox and sliding axle needs a lot of space before and after bearing points.
My first 4-speed sequential has proper gear pairs for 5th gear but I didn’t use that construction while it’s underdrive and I wanted direct or overdrive version. Although it’s difficult to find good ratios that have progressive gear steps I found one interesting gear pair combination. It has two ratios that are too close to direct gear but proper gear steps in lower gears so if you forget direct gear you get good progressive gear steps. So this gearbox is overdrive version that has no direct gear. I also found out that this gearbox could be 1 stud shorter. Here is how you can shorten gearbox: Change input’s axles to get axle joiner between 20 and 16 teeth gears. Then move input axle’s bush and two 12 teeth gears 1 stud rearward. Also move sliding axle’s 20 teeth gear right next to 12 teeth gear. Now you can move front brick segment 1 stud rearward. R.6. 3-speed, overall gear ratio 2,88: I haven’t designed 3-speed sequential gearbox before this version. It contains 3 important features in same gearbox so it was worth designing: it’s short while gear pairs take only 6 stud space between bricks, it has progressive gear steps and it doesn’t have S(16)-S(16) or XS(8)-S(16) gear pairs so it’s easy to shift.
R.7. 3-speed version II B, overall gear ratio 2,84:
This 3-speed version II B uses Su(12)-S(16) gear pairs which can’t be supported by brick frame. So that’s why this gearbox has studless frame. This version IIB has same useful features as previous version I: gear pairs take only 6 stud longitudinal space inside frame, it has progressive gear steps and it doesn’t have S(16)-S(16) or XS(8)-S(16) gear pairs so it’s easy to shift.
R.8. 3-speed version III B, overall gear ratio 3,33: This 3-speed version III B uses only Su(12)-S(16) and XS(8)-Mu(20) gear pairs which means two things: There is always double bevel type gear wheel in gear pairs so gearbox is easy to shift. Secondly you need studless frame to support these axles. Again gear pairs need only 6 stud longitudinal space inside frame so structure is quite compact. Despite the few used gear pairs this gearbox still has some progression in gear steps. While overall gear ratio is closer to 4-speed gearbox than 3-speed this gearbox is wide ratio version.
R.9. 8-speed truck version B, overall gear ratio 8,33: Main gearbox + splitter
This 8-speed sequential truck transmission has 4-speed main gearbox and splitter unit, both sliding axle versions. Sequential structure is not a problem while only splitter is shifted up and down during upshifting procedure, main gearbox goes only up and one gear at a time. If range-change unit was used situation would be more complicated while main gearbox would be shifted from 4th to 1st together with range change.
Also this transmission uses Su(12)-S(16) and XS(8)-Mu(20) gear pairs which can’t be supported by brick frame so this one has studless frame. All gear pairs have double bevel type gear wheel so this transmission is easy to shift. Gear steps are mainly 1,33 but two slowest compound shifts have step 1,41. Overall gear ratio is only 8,33 so this transmission is suitable for light and medium trucks only. Note that in some pics main gearbox’s gear order is shown without splitter as 1-2-3-4. To be more accurate gear order is 1/2-3/4-5/6-7/8 where odd gears mean splitter low and even gears splitter high. R.10. 8-speed truck version II, overall gear ratio 9,00: Main gearbox + range
Here is 8-speed sequential truck transmission that has 4-speed main gearbox and range-change unit. It wasn’t easy to find proper ratios for main gearbox so this transmission is more complicated than previous 8-speed with splitter. But ratios of main gearbox became slightly progressive. Overall gear ratio is only 9,00 so this transmission is suitable for light and medium trucks only.
Sliding axle main gearbox with range-change unit is problematic combination because you have to shift main gearbox from 4th to 1st together with range shift. Normally it requires jump through 3rd and 2nd gear but I changed main gearbox’s gear order to 1-4-2-3. This way 5th gear (1st high range gear) is right next 4th gear but jumps are in shifts 1-2 and 3-4. When you think both ranges main gearbox’s gear order is 1/5-4/8-2/6-3/7 where first numbers mean low range and second high range. R.11. 8-speed truck version III B, overall gear ratio 11,11: Main gearbox + range
Here is another 8-speed sequential truck transmission that has 4-speed main gearbox and range-change unit. While this transmission has XS(8)-Mu(20) and Su(12)-S(16) gear pairs studless frame is the only choice. Again main gearbox has some progression in gear steps. Overall gear ratio (11,11) is a little bit larger than in previous 8-speed transmissions but only 8 gears mean that this is light and medium truck transmission.
While this is overdrive transmission it works best with low speed motor. This transmission is not the smallest one so if you have lack of space check other sequential transmissions first. And if you have difficulties to figure out the construction from the pictures I recommend to download LDraw file or watch YouTube video Build it. Once again main gearbox’s gear order is changed to 1-4-2-3 to get easier range shift. So all in all gears are in order 1/5-4/8-2/6-3/7 where first numbers mean low range and second high range. R.12. 8-speed truck version IV, overall gear ratio 11,76: Range + main gearbox
This one is modernized version of my 8-speed sequential truck transmissions that has 4-speed main gearbox and range-change unit. It doesn’t use any old 14 teeth thin bevel gears but two new 28 teeth gear wheels. So, gear wheels are larger than in earlier 8-speed versions but design is simpler while 28 teeth gears help to get typical gear steps for 8-speed transmission. Also this one is overdrive gearbox so it works best with low speed motor.
This time main gears are in logical order which means more complex range shift 4-5 while you have to shift both range-change unit and between main gears 1st and 4th (through 2nd and 3rd). Top gear step 7-8 is slightly too high 1,40 while largest top gear steps in trucks I have found are 1,37 but in lego world this is not a problem, or is it? :-) So, if you need sequential transmission for mid range truck and 8 gears are enough here simple and logical design for you. R.13. 10-speed truck version B, overall gear ratio 9,89: Main gearbox + splitter Inspirer: Scania GS771
This 10-speed transmission is sequential version of M. 10-speed Transmission (with splitter) and it contains 5-speed main gearbox and splitter unit. Also this transmission has XS(8)-Mu(20) and Su(12)-S(16) gear pairs which need studless frame. While overall gear ratio is only 9,89 this transmission is for light and medium truck use only.
Note that gear order is not normal while 8th and 9th gear are swapped. Idea comes from Scania’s transmission and is to get halved gear steps for high speed driving meaning gear pairs 7-8, 8-9 and 9-10. So, gear order is 1/2-3/4-5/6-7/9-8/10 where first numbers mean splitter low and second splitter high. R.14. 12-speed Twin Splitter truck, overall gear ratio 12,80: Main gearbox + splitter Inspirer: Eaton Twin Splitter
This 12-speed transmission is sequential version of J.1. 12-speed Twin Splitter. It has 4-speed main gearbox and 3-speed splitter but no reverse gears. This sequential version is smaller design than my original twin splitter while sequential main gearbox is not so wide as synchro version with reverse gear. So you can locate gearboxes parallel which means that long sequential main gearbox is not a problem.
Ratios and gear steps of main gearbox are same as in my original setup but in splitter they are slightly different. Design also follows Eaton’s notation: gears are not 1-12 but main gears are 1-4 and splitter gears I-III. Sequential design is not very good in 3-speed splitter while in combined upshifts you have to shift main gearbox one gear up together with splitter shift from III to I (through II). But my original twin splitter had the same problem while its splitter is also sliding axle construction (H shift pattern in splitter would lead to 4x3 twin stick transmission). R.15. 12-speed truck, overall gear ratio 12,50: Main gearbox + range + splitter Inspirer: Scania GRS895
This 12-speed sequential truck transmission contains 3-speed main gearbox, splitter and range-change unit. Gearboxes are located parallel so this transmission is very short but wide. Gears are 1L-1H-2L-2H-3L-3H-4L-4H-5L-5H-6L-6H.
Gear steps are good while they vary only between 1,25-1,28 but overall gear ratio (12,50) is slightly small for the heaviest trucks. Range shift 3H-4L needs some attention while you have to upshift range, downshift splitter and downshift main gearbox from 3rd to 1st through 2nd gear. All gear pairs contain double bevel type gear or crown gear so this transmission is easy to shift. While gear wheels take only 6 studs space you can think to put this transmission transversal between truck frame, input near to cabin and output axle next to driven axles. One solution is to support topmost axle with upper long bricks, use next bricks and plates as middle layer and support bottom axles with lower long bricks. It’s also useful to move input axle forward and locate it to either upper or lower long bricks. If you need larger overall gear ratio you can check 12-speed transmission of Project 5590 or add crawler gear like in next two 14-speed transmissions. R.16. 14-speed truck, overall gear ratio 20,00: Main gearbox + range + splitter Inspirers: Volvo VT2814B & Scania GRS905
This 14-speed sequential transmission is enlarged version of the previous 12-speed sequential transmission. Structure is slightly different compared to 12-speeder but for 12 gears ratios and gear steps are same in both versions. New feature is crawler gear (doubled by splitter) and its gear pairs which makes this transmission’s frame 4 studs longer than in 12-speed version. Also sliding axle of main gearbox needs some more space outside frame. Gears are CL-CH-1L-1H-2L-2H-3L-3H-4L-4H-5L-5H-6L-6H.
While main gears are copied from previous 12-speeder also this transmission has good gear steps and it’s easy to shift due to used gear pairs. Structure is now longer but this transmission is still quite short, width is same as in 12-speed version. Now overall gear ratio (20,00) is large enough to be suitable for heavy trucks. R.17. 14-speed truck version II, overall gear ratio 31,25: Main gearbox + range + splitter, also 13-speed conversion Inspirer: Volvo I-Shift with crawler gears
Here is another enlarged version of earlier 12-speed (2x3x2) sequential transmission. It’s sequential sister transmission of earlier A.4. 14-speed transmission version IV. This 14-speed sequential version II is inspired by Volvo I-Shift with crawler gears so its use differs from normal 14-speeder. In normal use this transmission is like typical 12-speed range-splitter transmission (2x3x2 design). But when low speeds are needed you choose splitter’s extra crawler position (CR) with main gearbox’s gears I or II. This crawler position overrides normal splitter so crawler gears have larger gear steps than in normal splitter type transmission. Overall gear ratio is large so this is heavy and severe duty transmission. Gears are C1-C2-1L-1H-2L-2H-3L-3H-4L-4H-5L-5H-6L-6H.
There is also a 13-speed conversion of this transmission. Conversion is simple swap in crawler gear’s gear pair. In 13-speed version splitter’s crawler position is selected with main gearbox’s 1st gear. This gives overall gear ratio 20,00 so transmission suits to heavy duty trucks. If you abandon splitter’s crawler position you get earlier shown 12-speed range-splitter transmission. While there are no more than three gears in any gearbox gear wheels need only 6 studs space in this 14-speed transmission and its 13-speed conversion. Compared to earlier 12-speed transmission there is extra axle between range-change unit and splitter. So this transmission is short but wide. All gear pairs have double bevel type gear or crown gear so transmission is easy to shift. All in all here is two good and compact designs with large overall gear ratio for lego gearbox builders who want sequential transmission or don’t have transmission driving rings. R.18. 16-speed truck, overall gear ratio 16,33: Splitter + range + main gearbox Inspirer: ZF Ecosplit
I have had problems to make enough gear steps about 1,40-1,45 in sequential designs while you can’t always use 14 teeth thin bevel gears with sliding axles. But LEGO has released some time ago new 28 teeth gear wheel which I have named as ML (medium large) for my notations. With help of this new gear wheel new ratios allow this desired gear step for sequential design. So here is sequential 16-speed truck transmission that has splitter, range-change unit and 4-speed main gearbox. Gears are 1L-1H-2L-2H-3L-3H-4L-4H-5L-5H-6L-6H-7L-7H-8L-8H.
Main gearbox has quite large width and height due to large gear pairs but design is surprisingly short for 4-speed gearbox. Usually sequential 4-speed gearbox needs 10 stud length between bricks but this design takes only 8 studs. This time gears are in logical order so range change needs some attention while you have shift both range-change unit and between main gears 1st and 4th (through 2nd and 3rd). Splitter and range-change unit are underdrive and main gearbox overdrive but scaled ratios, gear steps and overall gear ratio are very realistic when compared to ZF Ecosplit. If you have difficulties to figure out the construction from pictures I recommend to download LDraw file or check video Building example. This transmission is sequential sister of K.1. 16-speed version I & K.3. 16-speed version III. R.19. 16+16R-speed tractor, overall gear ratio 14,70: Main gearbox + fwd/rev + range Inspirer: John Deere 6430 PowrReverser (TractorData)
This transmission is sequential version for 16+16R-speed synchro tractor transmissions shown in S. Tractor Transmissions. It contains 4-speed main gearbox, driving direction changer and 4-speed range unit (ranges A-D). It is also a big brother of the next 12+4R-speed tractor transmission in which 4-speed main gearbox and driving direction changer are replaced with 3+R-speed main gearbox.
Note that gear orders are illogical while front position has slowest gear in main gearbox but fastest range in range unit. This is because of compact design and driving direction changer which was difficult to locate between main gearbox and range unit. While driving direction changer uses spur gears XS(8) and S(16) it’s not very user friendly. So if you build this my guess is that you will use motor to change driving direction. But you can say that you have 32 different gears in your sequential transmission. :-) Ranges overlap each other because range steps are relatively small: A-B and C-D are 2,00 and B-C is only 1,50. Idea of smaller B-C is taken from John Deere’s transmission and is to get more gears for field working speeds (4-12 km/h). In real tractors lots of gears in middle speeds mean that there are many speeds where you can take advantage of engine’s maximum power. In lego world lots of gears with small steps gives lots of different driving speeds. But in this transmission choosing right gear is quite confusing while in many cases sequential ratios are in different ranges, check table Ratios sorted in picture Ratios to see what I mean. And the idea is not to use all these gears in upshifting procedure while they would need difficult two stick shifts. John Deere’s recommended upshifting sequence from stop to full speed is (A1)-(B1)-C1-D1-D2-D3-D4 so you first upshift only ranges and after them only main gearbox’s gears. But if you want to keep things simple just choose first suitable speed range with range unit and then adjust speed with main gearbox. R.20. 12+4R-speed tractor version A & B, overall gear ratio 10,80: Main gearbox + range Inspirer: John Deere 6430 SyncroPlus (TractorData)
This one is sequential version for 12+4R-speed synchro tractor transmission shown in S. Tractor Transmissions. It contains 3-speed main gearbox with reverse gear and 4-speed range unit (ranges A-D) so altogether you got 12 forward and 4 reverse gears. Using this transmission is quite simple while you first choose suitable speed range with range unit and then fine tune speed with main gearbox’s gears or choose to reverse. Available also version B with studless frame. Ratios and gear steps of range unit are same in synchro and sequential versions but in main gearboxes ratios vary a little while you can’t copy ratios of synchro version to sequential design. Once again range step B-C (1,50) is smaller than steps A-B and C-D (2,00). Reason comes from real tractors and is to get more gears suitable for field working speeds (4-12 km/h). While this transmission has two 4-speed gearboxes located to parallel design is quite compact for a sequential gearbox that has so many gears. And that is not all while you can add splitter (in real tractor powershift) or creeper unit to this transmission so you can get 24+8R-speed and 21+7R-speed versions. R.21. 6+3R-speed tractor, overall gear ratio 12,00: Main gearbox + range
This lego 6+3R-speed sequential tractor transmission doesn’t have direct inspirer while it’s combined from two kind of tractor transmissions. First one is Massey Ferguson’s 6+2R-speed which has 3-speed main gearbox with reverse gear together with 2-speed range unit. Second one is Ford’s 8+4R-speed which has four main gears plus ranges high, low and reverse (2+R-speed). In lego design three main gears are taken from Massey Ferguson and 2+R-speed auxiliary from Ford.
In lego design idea is to get maximum number of gears with minimum size by using only two 3-speed sequential gearboxes. So if you have difficulties to fit transmission to your lego tractor and need sequential design here is small setup for you.
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