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Ari Holopainen / junkyard1 | |
| JUNKYARD PART I: Main Page: A.3. Old 14-speed transmission version III, overall gear ratio 20,83: Main gearbox + range + splitter Inspirer: Scania GRS905 While gear steps and overall gear ratio are not good at version I and II, I made a new version. Now overall gear ratio is near to usual 15-20 and gear steps vary only between 1,25-1,28. Crawler gear has larger gear step on purpose so gear step CH-1L is 1,33.
I’m not sure is this correct, but I have understood that Scania’s 12-speed transmission is just 14-speed transmission without crawler gears, there are no changes in ratios or gear steps. With this manner you can also make 12-speed conversion of this lego transmission, just remove crawler gear’s 16 teeth clutch gear. New overall gear ratio is only 12,50 so 12-speed version suits to linehaul trucks. A.4. Old 14-speed transmission version IV, 6 reverse gears, overall gear ratio 40,00: Splitter + range + main gearbox, also 12- & 13-speed conversions Inspirer: Volvo I-Shift with crawler gears
I-Shift is Volvo’s 12-speed automated transmission. Now there is an option to have crawler gears in this transmission and modification is done in very interesting way: there is new high reduction gear pair between clutch and splitter unit. Normal front-mounted splitter gives 2 alternative gear pairs to get torque to main gearbox’s side axle. This new gear pair doesn’t add crawler in main gearbox but turns splitter into 3-speed version. In normal 12-speed use splitter’s crawler position is not used but when you need crawler gears this position is used with main gearbox’s gears 1st, 2nd and reverse (gives gears C1, C2 and RC). Here crawler position overrides normal splitter. Reverse crawler gear can be used also with high range so this transmission has 6 reverse gear altogether: RC, RL and RH in both ranges. Gear step RC-RL is very large and gear step RL-RH is normal splitter step which means 1 extra slow, 3 slow and 2 fast reverse gears. This description is from setup with largest number of gears, Volvo lets you choose from 4 different setups: 1 or 2 crawler gears with or without reverse crawler. Check Inspirer link for more information.
This crawler gear arrangement also means that gear step between crawler gears (C1-C2) is as large as main gearbox’s gear step 1-2. (In normal crawler gear system gear step CL-CH would be as small as other splitter steps.) Also gear step C2-1L is quite large. While normal 12 gears have already normal overall gear ratio adding 2 large gear step crawler gears give this transmission very large overall gear ratio. All in all this transmission is a little bit complex to operate but driver doesn’t need to pay attention while transmission is automated. Lego version has very good gear steps: they vary only from range shift’s 1,27 and splitter shifts’ 1,28 to compound shifts’ 1,30. As described earlier gear steps of crawler gears are larger: gear step C1-C2 is 1,67 and C2-1L 1,50. While this lego version is manual gearbox you have to be more careful with splitter unit. In conclusion: In normal use remember to use only splitter’s positions high and low. This is like operating normal 12-speed transmission with splitter and range-change unit. When low speed or high torque is needed choose splitter’s position crawler with main gearbox’s gears 1st, 2nd or reverse. Available is now more detailed shift pattern in picture Ratios or 14-speed gearbox ver4 pic1. You can also modify this lego transmission in two ways. If you replace Su(12)-M(24) gear pair with S(16)-Mu(20) in crawler gear’s gear wheels and change places of some gear pairs you get 13-speed version. In this version you choose splitter’s crawler position with main gearbox’s 1st or reverse gear for low speed driving, so altogether you have 13 forward gears and 6 reverse gears. If you remove crawler gear’s gear pairs and rearrange the rest of the auxiliary’s gear pairs you get 12-speed version which is a little bit shorter than original 14-speed. 12-speed version has overall gear ratio 16,00 and 4 reverse gears. Main gearbox stays unchanged in both versions. Check next pictures for these conversions. Now available also sequential sister transmission if you don’t have transmission driving rings. Check R.17. 14-speed truck version II in R. Sequential Transmissions. For another severe duty transmission with extra slow crawler gears I recommend to check section G. 11-speed Transmissions inspired by Eaton Fuller 9ALL. D.1. Old 9-speed transmission version I, overall gear ratio 21,60: Range + main gearbox Inspirer: Eaton Fuller convertible 9 to 13
This 9-speed transmission is a little brother of the earlier 13-speed transmission, Version II. Now auxiliary gearbox has only range-change unit, so its length is very short. Also the whole transmission is a quite compact construction.
This transmission is very easy to convert into 13-speed transmission. This auxiliary gearbox already has gear ratios low range and high range, splitter low (means gears C-1-2-4-5L-6L-7L-8L in 13-speed transmission). All you need is to add gear wheels of the high range, splitter high and more longitudinal space for the sliding axle construction to get gears 5H, 6H, 7H and 8H. Check previous 13-speed version III to see how to do conversion. D.2. Old 9-speed transmission version II, 1 reverse gear, overall gear ratio 17,14: Main gearbox + range Inspirer: Eaton Fuller synchromesh 9-speed & ZF Ecomid
Like previous 9-speed transmission also this version has 4-speed main gearbox with crawler and reverse gear plus range-change unit. New feature is that range change is integrated to main gearbox’s shift pattern. When you want to shift to high range you move shift lever far right over 3-4 line before you shift to desired gear. Shift to low range happens when shift lever is moved to R-C line. This way you can operate all the gears with only one shift lever. It also means that you can’t misuse crawler gear in high range or don’t have high reverse gear.
One annoying thing is that range shifter comes over main gearbox’s shift pattern. If you locate shift pattern higher you can locate range shifter under it. It simplifies range shifter a lot but makes shift pattern less accurate, check next pictures. Other annoying thing is that range-change unit is rotated 90 degrees due to its shifting system. If you use lego flexible cables you can get range-change unit’s orientation same as in main gearbox.
In real world this kind of range shifting system is called double H shift pattern. In low range shift lever centers itself to line 3-4 and in high range to line 5-6 which are not same line. This gives simple operation so that you tap shift lever right from line 3-4 to shift to high range and left from line 5-6 to shift to low range. So other gears in same range are in different direction than range change to minimize shifting errors. E. Old 18-speed Transmission, 4 reverse gears, overall gear ratio 24,00: Range + main gearbox + splitter Inspirer: Eaton Fuller 18-speed transmission
This transmission is almost like Eaton Fuller 18-speed gearbox. It has 18 forward gears and 4 reverse gears. In real Fuller transmission range-change unit and splitter unit are in the same auxiliary gearbox, but this lego version has separate range and splitter unit. Forward gears are: CL-CH-1L-1H-2L-2H-3L-3H-4L-4H-5L-5H-6L-6H-7L-7H-8L-8H.
This gearbox is pretty long. If you have problems with longitudinal space, you can build this gearbox without splitter unit. In that case you will get synchromesh 9-speed gearbox.
G.2. Old 11-speed transmission version II, overall gear ratio 37,50: This version II has 3 modifications compared to version I: range-change unit is now sliding axle solution with slightly slower deep reduction range, main gearbox is changed from underdrive to direct drive and reverse gears are a little bit faster.
I.1. Old 10-speed transmission version I, overall gear ratio 18,00: Range + main gearbox Inspirer: Eaton Fuller FR-10C In this first version solution for gearbox matching is that gear steps are mainly 1,39-1,43 but gear steps 3-4 and 8-9 are only 1,26, which means 2 exceptions in geometrical gear steps. In reality smallest step should be 4-5 and 9-10. There is also another annoying thing: reverse gears are too slow. Overall gear ratio is near to inspirer’s ratio series C.
I.2. Old 10-speed transmission version II, overall gear ratio 15,00: Main gearbox + range Inspirer: Eaton Fuller FR-10B I wasn’t happy about the (now replaced) version I so I designed version II (version IV of all 10-speeders). This time gear steps are mainly 1,33, range shift is 1,35 but gear steps 3-4 and 8-9 are 1,41. Gear steps are still not good but they are much better than in replaced first version. Another improvement is that reverse gears have now better ratios. This time overall gear ratio is near to inspirer’s ratio series B. Unlike many other transmissions in these pages this is an overdrive gearbox.
J. Old 12-speed Twin Splitter Transmission, 3 reverse gears, overall gear ratio 12,50: Main gearbox + splitter Inspirer: Eaton Twin Splitter
This transmission has 4-speed main gearbox and 3-speed splitter unit. There are also 3 reverse gears. There is available also alternative setup in which main gearbox and splitter are located parallel. To get more compact and simpler design reverse gears have different ratios and new location in shift pattern compared to original design. Also splitter’s gear order is changed to low-high-medium while in original design it’s high-medium-low (from front to rear). For usable shift levers of splitter check building examples. The idea in real twin splitter transmission is that you don’t have to shift main gearbox often, most of the shifts are easy splitter shifts. Top three gears cover quite large speed area, so you need only splitter shifts from higher city speed limits to highway speeds. On the other hand, skipping gears is more difficult than in transmission with 2-speed splitter. If you shift only with main gearbox (e.g. from 1st to 4th gear) there is a huge gear step, which is usable only in low gears with unloaded truck or in downshifting. In other situations you have to shift with splitter even if you skip gears. One possible upshifting combination is 3-5-7-9-10-11-12. 3-5 and 5-7 are combined main gearbox and splitter shifts, 7-9 is a splitter shift, 9-10 is a combined shift and the rest are splitter shifts. I’m not sure why it’s called twin splitter, but here is my guess. You have 2 splitter units, the first one has an underdrive gear and a direct gear and the second has a direct gear and an overdrive gear. When you put these 2 together, you don’t need 2 direct gears. Altogether you’ve got 2 splitters and 3 speeds => twin splitter. N.2. Old twin stick 4x4 transmission, overall gear ratio 18,75: 4-speed main + 4-speed aux
Here is another type of twin stick transmission. This time main gearbox has only 4 speeds. 4-speed auxiliary is used same way as in previous 5x4 transmission so the number of gears you’ve got is 4x3+1=13. Available is also alternative setup with parallel mounted auxiliary and main gearbox. For shift lever axles use 3rd longitudinal brick between gearboxes and put axles only half studs inside it.
One notable thing is that this transmission is quite simple structure in both setups but gear steps are not very good. Gear steps 1,20 and 1,25 are ok but steps 1,33 and 1,35 together with overall gear ratio are too large for typical twin stick transmission. Twin stick transmissions need small gear steps while in old trucks usable engine rpm range was very narrow. Also this auxiliary has basic shift pattern but gears 3 and 4 should be swapped for more realistic design. O.3. Old 6-speed transmission version II, light truck, overall gear ratio 8,93: Inspirer: ZF S6-66 Here is 6-speed version. It’s more complicated than 5-speed version while you need so many different gear steps after synchro parts.
There is an additional splitter unit which enlarges ZF’s transmission S6-66 to 12-speed version. Check O.8. 6-speed & 12-speed for more information. O.4. Old 6-speed transmission version IV, light truck, overall gear ratio 8,16: Inspirer: ZF S6-66 Here is another 6-speed light truck transmission. Structure before synchro axles is simpler than in previous 6-speed version but after synchro axles structure is more complicated. All in all this transmission is quite small for 6 speeder that has progressive gear steps.
One notable thing in this transmission is XS(8)-M(24) gear pair after synchro parts. So there are significant overdrive situations in some gear wheels in some gears which can lead to bad efficiency. So it’s worth to test this transmission before using it in lego vehicle. While input axle is supported by two technic brick 1x2 with 2 holes you may have difficulties to attach studded lego motor to the input axle. If you need hints to solve this problem check 4-speed version II in personal car transmissions. O.6. Old 7-speed transmission, light truck, overall gear ratio 10,71: Inspirer: Eaton Fuller 7-speed This 7-speed transmission is a big brother of later shown 5-speed version II and 6-speed personal car transmissions. Ratios of higher gears are same as in those gearboxes but gear pairs are placed slightly different.
In my opinion 7+R-speed transmission is largest you can handle with single shift lever and H shift pattern. 6 forward gears keep things simple when shift lever centers itself to 3-4 line, movement to right gives 5-6 line and movement to left gives 1-2 line. And if reverse gear is behind lock or extra spring load 6+R-speed can be shifted without risk of wrong gear. In 7+R-speed lines R-1 and 6-7 need some extra spring resistance or other methods that you don’t accidentally shift to those gears while shifting to gears 2-5. This is when neutral is between lines 2-3 and 4-5. If neutral is in line 4-5 only line R-1 needs extra spring resistance. P.13. Old 6-speed version III personal car transmission, overall gear ratio 5,56: Note that 6-speed version II is light truck transmission, that’s why this one is version III. In this version structure before synchro parts is simple but after them a little bit complicated. So model is flat but long and wide for a personal car transmission.
This version is based on 6-speed version I and 5-speed version II while top 4 gears have same ratios in all versions. The idea in this version is to get rid of pre-axles before synchro axles. That’s why ratios of lower gears are now different and structure after synchro axles is more complicated. Actually progressive gear steps required quite complicated structure also in earlier 6-speed version. P.14. Old 7-speed version II personal car transmission, overall gear ratio 6,43: 7-speed personal car manual transmissions are still quite rare but you can find them in some sport cars like Porsche 911, Chevrolet Corvette or Aston Martin V12 Vantage. While these sport car transmissions are close ratio versions overall gear ratios are only about 4,9-6,3 which is not much for 7-speed transmission. When gear step 6-7 is not smaller than about 1,19 this means that other higher gear steps are pretty small too. All in all lego version has quite realistic gear steps and overall gear ratio, actually it has more progression in gear steps than in those sport cars. Major difference is that those real gearboxes have 2 or 3 overdrive gears while lego version is direct drive.
If you prefer overdrive version this lego gearbox is easy to modify to double overdrive version: you just change input from present axle to axle right next to it. This modification changes all ratios but doesn’t affect to gear steps or overall gear ratio.
If you abandon 1st gear and remove its parts you get 6-speed transmission with overall gear ratio 4,02. This new gearbox is close ratio version for sport cars. Both direct drive and overdrive versions are available. P.16. Old 4x2-speed personal car transmission, overall gear ratio 4,59: Inspirer: Mitsubishi Cordia Super Shift Mitsubishi used this kind of transmission in late 70’s and 80’s. It’s based on normal 4-speed gearbox with progressive gear steps but contains also 2-speed auxiliary, which is splitter-type. Auxiliary’s shift lever has positions Power (low) and Economy (high). Altogether you have 8 gears but it’s difficult to use them all in upshifting procedure while every other shift would be 2 stick shift. Typical use is to accelerate with Power mode and drive with Economy mode so you have 5 progressive gears. Auxiliary is handy in speed where upper gear has too low engine rpm but lower gear too high rpm while you can choose gear between them. If you drive in Economy mode and need to slow down a little or accelerate fast you can quickly downshift to Power mode and after situation upshift to Economy mode. While auxiliary shift is only forward/rearward movement there is no risk to shift to wrong gear.
P.17. Old 3-speed & transfer case version III, overall gear ratio 3,00: Transfer case’s gear step 2,40 Inspirer: Willys Jeep This transmission is based on old legendary off-road vehicle, Willys Jeep. It contains 3-speed main gearbox with reverse gear and 2-speed transfer case, which is part time 4WD. On the road vehicle is rear wheel drive but for difficult conditions you switch on front axle’s drive. While there is no centre differential in this transmission it’s not recommended to use 4WD in good driving conditions. Transfer case has 2 shift levers: one is for low and high selection and other switches front wheel drive on and off.
Note that front and rear output axles are coaxial but they are not directly connected together. (Front output axle is grey and rear output axle black.) To enable switching front axle’s drive on and off connection is done by four 12 teeth gears and side axle. While 12 teeth gears are double bevel type switching front wheel drive on should be easier than in versions based on 8 or 16 teeth gears. Also main gearboxes of B. 12-speed transmission can be used as 3+R-speed personal car transmissions. On the other hand this main gearbox can be used in that 12-speed transmission as alternative main gearbox. Alternative setup for this transfer case version III and other transfer cases are now located in chapter C. Transfer Cases on page Basic & special designs Q.1. Old 4-speed double clutch gearbox, overall gear ratio 4,50:
This 4-speed double clutch gearbox has pretty large gear steps so it’s wide ratio version.
While this lego version is not automatic you have to shift gears manually. Here is how it works: First you shift 1st gear with shift lever 1-3 and then move off with engaging drive line 1 in double clutch unit which is in input axle. While driving with 1st gear you preselect 2nd gear with shift lever 2-4. When it’s time to shift you only shift double clutch unit. Now in 2nd gear drive line 2 is active but 1st gear is still engaged. It’s time to disengage it and preselect 3rd gear. And again shifting happens with double clutch unit. 4th gear is shifted with same manner. And why it’s designed so that synchro parts are on the output axle? Gearbox is so long and there are difficulties to arrange shift levers. Well, reason for that is in 1st and 2nd gear. If synchro parts are located right next to double clutch there will be large ratio after them in 1st and 2nd gear. So when driving in high gears 16 teeth clutch gears of 1st or 2nd gear will spin very fast which means bad efficiency in lego world. That’s why it’s better to locate synchro parts at the end of the drive lines. Lego version is not so handy as real double clutch gearbox but it’s remote control friendlier than truck or tractor gearboxes I have designed. With 3 small motors it’s possible to build remote control shifting system. Shifting mechanisms don’t have to stop in neutral while gears are preselected. Only time you need a neutral in double clutch unit is if you want to stop without stopping driving motor. Q.2. Old 4-speed double clutch gearbox version II, overall gear ratio 3,33: Operational principle of this version II is same as in previous double clutch gearbox so if you need information how it works check previous chapter. In this version gear steps and overall gear ratio are smaller so this is close ratio version.
Porsche has had 4-speed double clutch gearboxes in the 80’s but I didn’t find ratios of those gearboxes. My guess is that ratios of this lego version are closer to ratios that Porsche used, while sport cars often use close ratio gearboxes. R.1. Old 4-speed sequential gearbox, overall gear ratio 4,00: It’s also possible to build a 4-speed sequential gearbox with progressive gear step, but it wasn’t easy to find proper gear wheels and ratios. There are a suitable gear pairs for the fifth gear but it’s not very practical to build 5-speed sequential because it will be too long construction.
R.2. Old 4-speed sequential gearbox version II, overall gear ratio 4,29: Here is another version of 4-speed sequential transmission. This time it’s overdrive version. Overdrive gear is more complicated than other gears because proper ratio needed thin 14 teeth bevel gears which can’t be used with sliding axle. That’s why there is a side axle. This version II is one stud shorter than previous sequential gearbox. Overall gear ratio is quite large for a 4-speed gearbox so this one is wide ratio version.
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