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Ari Holopainen / truck1 | |
| C. 13-speed Transmissions: Range/splitter + main gearbox Inspirer: Eaton Fuller 13-speed transmission The idea of this transmission is to get progressive gear steps (used in personal cars) available in truck transmission, in which range-change unit requires normally geometrical gear steps. In this case there is a large gear step between crawler (available in low range only) and 1st gear, and then there is a basic geometrical gear step in other low range gear pairs 1-2, 2-3 and 3-4. High range has gears 5-8 and they are splitted, so the number of gears is doubled and gear steps are halved in high range. Gears are: C-1-2-3-4-range_change-5L-5H-6L-6H-7L-7H-8L-8H. 13-speed version I is taken from my rear-engined Lego 4WD vehicle and version II is normal truck version of it. Best design so far is version III (truck design). Note: Early versions have too large overall gear ratio, it should be 15-20. Reason of this exception is too slow crawler gear. Without crawler gear ratios and gear steps are pretty realistic. C.1. My first version, rear engine 4WD, overall gear ratio 28,80: Used in my Lego 4WD vehicle version 7
This construction is used in my Lego 4WD vehicle version 7 which is a rear engine solution. Check Vehicles to get more info. Main gearbox and auxiliary were earlier modeled separately but now is available whole transmission in one LDraw file. C.2. Version II, 3 reverse gears, overall gear ratio 25,92:
Here is an alternative setup which is near to normal truck construction with front-mounted engine and rear-wheel drive. One possible problem in this setup is the height of the gearbox. Basic idea in this construction is that motor and auxiliary gearbox are above the front axle but the main gearbox is located under the driver’s cabin. If you need a lower gearbox construction, vertical flip in auxiliary gearbox helps a little, but it will locate motor higher.
C.3. Version III, 3 reverse gears, overall gear ratio 20,57:
This 13-speed version III has some modifications compared to previous version II. Auxiliary gearbox is tried to make more compact so gear pairs take only 6 stud space between bricks. Main gearbox is changed from underdrive to direct drive version and gear step between crawler and first gear is smaller. This transmission is one good choice for gearbox builders.
This 3-speed auxiliary has simple and compact design with good efficiency. Only problem is shifting to high split in high range due to S(16)-S(16) spur gear pair. Now is available also synchro version of this auxiliary. For more info check A.7. Auxiliary 3-speed gearbox, compound splitter/range-change unit on page Basic & special designs. D. 9-speed Transmissions: Here are 9-speed transmissions, which contain 4-speed main gearbox with crawler and reverse gear plus range-change unit. Forward gears are: C-1-2-3-4-range_change-5-6-7-8. Typical use for 9-speed transmission is mid-range or heavy duty truck itself without trailer. So total weights suit to middle-sized truck engines which has wider torque peak and speed range than larger engines. This means that larger gear steps of 9-speed transmission are not a problem. But higher total weights in truck and trailer use means you need larger engines and more gears with smaller steps to optimize performance. Close ratio versions of 9-speeders are typically used in lighter hauling like delivery and wide ratio versions in vocational duties like dump trucks. To improve wide ratio versions’ performance in higher speeds they usually make top gear step 7-8 (also step 3-4 due to range-change unit) smaller than other steps or alternately slightly progressive gear steps in main gearbox. In lego designs version I has basic setup with geometrical gear steps and alternative ratio copy setup with slight progression. Also version II has now slight progression. Version III has significantly smaller top step 7-8. More info about this smaller top gear step is at the end of chapter O.10. 8-speed version II. These lego transmissions are inspired by Eaton Fuller, ZF Ecomid, Volvo and Scania but at least also Mercedes has own designs of 9-speed transmissions. D.1. Version I, 2 reverse gears, overall gear ratios 20,00 & 16,93: Range + main gearbox Inspirer: Eaton Fuller 9-speed B ratio (like RTX-14609B in Eaton Transmission Specifications Catalog)
These 9-speed version I remake & alternative setup are inspired by older Eaton Fuller 9-speed transmissions and their large gear step B ratio set. So, these lego setups are wide ratio transmissions for trucks without trailer like dump trucks and other vocational duties, especially for lego American trucks. Remake is very simple and compact version with basic lego ratio set and alternative setup is larger and more complex ratio copy of 9-speed Fuller B ratio. Remake has several improvements compared to original version which is moved to page Junkyard if you want to check it. So, original underdrive version with sliding axle auxiliary is changed to full synchro direct drive version. As an optional overdrive version for low speed lego motor you can take output from right axle under synchro axles. Despite the new synchro auxiliary design is even shorter so this remake is the most compact inline setup in my heavy duty truck transmissions. With motor total length is still only 18 studs together with 8 stud width. Design is also modernized so it uses new 28 teeth double bevel gear instead of old 14 teeth thin bevel gears. This change also gives better ratio set although top step 7-8 (and step 3-4 due to range-change unit) is still too large 1,40 while in Fullers it’s 1,37 or less. Alternative setup is longer and more complex design with lots of old 14 teeth thin bevel gears. But it’s very accurate ratio copy of Fuller’s design including slight progression in main gearbox, accurate step 1,37 (rare with legos) between two top gears and slightly slower reverse gear than crawler gear. You can check ratio and gear steps differences between lego setups and Fuller transmission from picture ratio comparison. So, here is two setups for heavy duty trucks without trailer: remake is small and simple lego design and alternative setup has very accurate ratio set for reality seekers. D.2. Version II, 1 reverse gear, overall gear ratio 12,60 REMAKE: Main gearbox + range Inspirer: ZF Ecomid & Eaton synchromesh 9-speed
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.
This lego design is remake with better ratio set and design. New ratio set is closer to ZF Ecomid with some progression but Eaton’s synchromesh 9-speed is not far away either. You can check differences from picture Ratio comparison. Lego design is improved so that both main gearbox and range-change unit are longitudinal and range change’s shifting system transfers transversal shift lever movement to longitudinal axle movement. Original design was problematical while it had geometrical wide ratio ratio set and transversal range-change unit. Also shifting system was not very optimized. But original design is still available on page Junkyard if you want to check it. 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 operating 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. Double H shift pattern gives driver illusion that he/she shifts single 9-speed main gearbox although main gearbox is shifted through twice, first in low range and then in high range. With double H shift pattern you get very simple and logical operating but price is that you lose high range reverse gear. D.3. Version III, 2 reverse gears, overall gear ratio 17,01: Main gearbox + range Inspirer: Volvo VT2009B & Scania GR905
Here is one more 9-speed transmission that has 4-speed main gearbox with crawler gear and range-change unit. There are also two reverse gears. This time main gearbox and range-change unit are located parallel. So this lego transmission is short and flat but wide. And if necessary you can still shorten this transmission by one stud: move most front Su(12)-Mu(20) gear pair inside frame behind synchro parts, there is enough space where bushes are.
Gear step 7-8 (also 3-4) is smaller than other steps of main gearbox and this feature is copied from Volvo’s and Scania’s transmissions. This smaller step makes transmission more usable in high speeds. More info about this is at the end of chapter O.10. 8-speed version II. On the other hand gear step C-1 is larger than main steps. Gear steps and overall gear ratio of lego version are close to Volvo’s transmission but ratios are all different while lego version is overdrive and Volvo’s transmission direct drive. Other notable thing is that how close Scania’s and Volvo’s ratios and gear steps are to each other. Check picture called Ratio comparison. In lego version three transmission driving rings (synchro parts) on the left belong to main gearbox and the last one on the right is for range-change unit. It’s a little bit tricky to get shift levers for these gearboxes but here is how you can do it: First put longitudinal brick with holes between gearboxes and shift lever axles only half studs inside it. Then on the other end of the axles use bushes on the both sides of the longitudinal bricks. This way you can lock axles on their positions. I would have used horizontal shift lever for range-change unit but one of the low range’s axles is on the way so you couldn’t do it. For more compact design you can also try this: Use 8 studs axle for main gearbox’s shift lever and put bush on the right side of the left brick. This prevents axle to slide to left. On the right side use only brick without bushes. Then use axle pin for range-change unit’s shift lever and put 3rd brick on the right side of this range lever. While range lever is between two bricks it’s well supported. Range lever also prevents main gearbox’s shift lever axle to slide to right. 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. E. 18-speed Transmissions: In these 18-speed transmissions version I & version II are inspired by Eaton Fuller 18-speed manual transmission, professional extreme trucker’s only choice. This design is 2x4x2+2 meaning 4-speed main gearbox with crawler gear (C) plus splitter (L & H) and range-change unit, and altogether there are 4 reverse gears. So, forward gears are: CL-CH-1L-1H-2L-2H-3L-3H-4L-4H-range_change-5L-5H-6L-6H-7L-7H-8L-8H. Version III is inspired by Eaton Endurant XD, automated 18-speed transmission. Its design is 2x3x3 meaning 3-speed main gearbox, 3-speed splitter and range-change unit, altogether you got 6 reverse gears. In lego version notation goes so that main gears in low range are 1-3 and in high range 4-6, and splitter gears are I-III. E.1. Version I, 4 reverse gears, overall gear ratio 20,57: Main gearbox + range + splitter Inspirer: Eaton Fuller 18-speed transmission
As described earlier this lego version I is 2x4x2+2 design. It’s also underdrive version for high speed lego motor and old school version using 14 teeth thin bevel gears but without new 28 teeth double bevel gear or 20 teeth clutch gear.
This lego version is remake in which parallel mounted range-change unit and splitter give shorter design, also shift levers are better placed giving better usability. Range-change unit is the only sliding axle design to maximize easy synchro shifts, but few sliding axle shifts should also be easier while there is double bevel gear in all range-change unit’s gear pairs. Original design is still available on page Junkyard if you want to check it. E.2. Version II, 4 reverse gears, overall gear ratio 20,00: Splitter + range + main gearbox Inspirer: Eaton Fuller 18-speed transmission
Also this version II is 2x4x2+2 design and inspired by Eaton Fuller 18-speed manual transmission. This lego version is overdrive design for low speed lego motor. Parallel mounted splitter and range-change unit gives quite compact design with well placed shift levers. Also this version has synchro main gearbox and splitter and only range-change unit is sliding axle design. And range-change unit has double bevel gear in all gear pairs so shifting should be always easy in this lego transmission.
This lego version mixes old school 14 teeth thin bevel gears and modern 28 teeth double bevel gear (ML, medium large in my notation). This mixing gives lego version quite accurate ratio set. Major difference is that lego version has only one overdrive gear while Eaton Fuller is double overdrive. Gear steps have minor differences like that lego version doesn’t have Fuller’s slight progression. You can check differences from picture Ratio comparison. If you have 20 teeth double bevel clutch gear you can use it in reverse gear and take power directly to output axle via 20 teeth double bevel gear. This way you get rid of lower reverse gear axle and 8 teeth gears. Conversion doesn’t change ratios but gives simpler design with better efficiency. E.3. Version III, 6 reverse gears, overall gear ratio 21,60: Main gearbox + splitter + range Inspirer: Eaton Endurant XD
This 18-speed version III is completely different kind of transmission: it’s 2x3x3 design inspired by Eaton Endurant XD, automated 18-speed transmission. While both main gearbox and splitter are 3-speed designs lego notation differs from versions I & II. Low range main gears are 1-3, high range main gears 4-6 and splitter gears I-III. This design also gives 6 reverse gears.
In lego construction main gearbox is on the front right and range-change unit rear right. They are connected with long inline splitter on the left. Parallel design gives some shortcuts in power flow between main gearbox and splitter via clutch gears. Lego version’s ratio set is pretty realistic: major difference is that lego version has one overdrive gear but Eaton Endurant is double overdrive. Gear steps and overall gear ratio have only small differences. Endurant’s gear steps are all 1,19-1,20 while in lego version they vary between 1,16-1,22 but being mainly 1,20 due to splitter. You can check differences from picture Ratio comparison. Building note: it’s not clearly shown in pictures but there are only two bricks per axle. Eaton’s 12-speed Endurant HD and 18-speed Endurant XD are sister transmissions with identical main gearbox and range-change unit. Only difference is that HD has 2-speed splitter with larger gear steps while XD’s splitter is 3-speed with smaller gear steps. Also this lego version has sister design: for 12-speed little sister check chapter B.2. 12-speed version II. F. 15-speed Transmissions, 3 reverse gears: 3-speed aux + main gearbox Inspirer: Eaton Fuller Versatile 15-speed (like RT-14915 in Eaton Transmission Specifications Catalog) These gearboxes are based on 10-speed transmission with 5-speed main gearbox and a range-change unit. In this case you have not only low and high range but also a deep reduction range. So you’ve got 10 road speeds and 5 deep reduction gears. One notable thing is that low range (gears 1-5) and deep reduction range (gears L1-L5) overlap each other. In version I you shift two gears down in main gearbox when shifting from deep reduction range to low range (for example from gear L3 to 1st gear). Altogether you’ve got 13 progressive speeds. In versions II-IV and Eaton’s transmission you shift only one gear down in main gearbox when shifting from deep reduction range to low range so they have 12 progressive speeds. And I recently found out that 15-speed Fullers have same ratio set in low and high range as older close ratio 10-speed Fullers. This relationship can be copied to these 15-speed lego designs and make 10-speed conversions by removing deep reduction range. 15-speed version III & IV have shorter 10-speed conversions as an example of these Eaton’s modular designs. For lego builders I recommend version III as basic lego design and version IV as advanced ratio copy of real Fuller. F.1. Version I, overall gear ratio 19,44:
Here is my original design. While it has quite long auxiliary gearbox I tried to rearrange auxiliary’s gear pairs and got alternative setup, which is 4 studs shorter. There is also complete shift lever for auxiliary. Only change in main gearbox is that front bearing point of first synchro axle is changed. While both versions have same gear pairs modification doesn’t affect to ratios or gear steps.
In this version I & alternative setup you shift two gears down in main gearbox when shifting from deep reduction range to low range. So you have 13 progressive speeds. Check Jumps in picture Ratios to see all shifting possibilities. F.2. Version II, overall gear ratio 16,67:
Also in this version II you have overlapping deep reduction and low range. Now you shift one gear down in main gearbox when shifting from deep reduction range to low range so you have 12 progressive speeds. Check Jumps in picture Ratios to see all shifting possibilities. Other modifications in this version II are synchromesh auxiliary and faster reverse gears.
You may notice that auxiliary’s deep reduction range could be arranged simpler: first you take input from low range’s 16 teeth clutch gear to deep reduction clutch gear and then use Su(12)-Mu(20) gear pair to get in main gearbox’s input axle. Problem is that it gives gear step 1,67 which is same as in main gearbox so you will have some same ratios in deep reduction and low range. Present more complicated arrangement gives gear step 1,71 so some ratios in deep reduction and low range are close to each other but not same, just like in Eaton’s transmission. Nowadays this 15-speed version II is not my best design, next modified versions III & IV has same ratio set except reverse gear but in smaller size. F.3. Version III, overall gear ratio 16,67: Also 10-speed conversion
This 15-speed version III is upgrade for previous version II offering same ratio set with more compact construction. Auxiliary has now inline shift levers giving few studs more narrow gearbox and new reverse gear makes design one stud shorter. Price is that auxiliary needs two shift levers and slower reverse gear is less realistic for this transmission. Again design has 5x2+2=12 progressive speeds so you shift one main gear down when shifting from deep reduction range to low range.
I found out some time ago that old close ratio 10-speed and 15-speed Fuller are sisters with one difference: 10-speed has shorter 2-speed auxiliary with low and high range and 15-speed 3-speed auxiliary with additional deep reduction range. Their ratio sets are identical except that additional deep reduction range. So here is also 10-speed lego conversion in which removed deep reduction range shortens design three studs. If you don’t have old 14 teeth thin bevel gears but new 28 teeth gear (ML, medium large in my notations) instead there is a simple modernization in auxiliary for 10-speeder without ratio changes: replace XS(8)-M(24) and Su(12)-Th(14) gear pairs with XS(8)-XS(8)-ML(28) gear train. One notable thing in 15-speeder is that there is a long multi-piece axle from auxiliary to main gearbox. So it’s possible that it bends too much under high load and middle gear pairs lose their mesh. If problem occurs you can use same High torque kit as 15-speed version IV. Basic lego design causes that gear steps vary quite a lot in these transmissions. But they are alternately too low and too high so in average ratios and overall gear ratio follow quite well real Eaton’s transmission. Check picture Ratio comparison (10-speed without deep reduction gears L1-L5 and RLL). So, here is two usable and realistic lego transmissions for older American trucks: simple and compact 10-speed or more versatile 15-speed. F.4. Version IV, overall gear ratio 16,67: Also 10-speed conversion
This 15-speed version IV is pretty much same as version III but with two improvements. Auxiliary is rearranged so shift lever of high and low range is closer to main gearbox. In main gearbox new gear pairs after synchro parts give that gear steps don’t vary so much as in version III. So you can say this is almost a ratio copy of real 15-speed Fuller, you can check differences between lego versions and real Fuller from picture Ratio comparison 15-speed.
Again design has 5x2+2=12 progressive speeds so you shift one main gear down when shifting from deep reduction range to low range. For more info check Jumps in picture Ratios 15-speed. But main idea is to enjoy simple operating as 10-speed transmission on highway duties but when on/off highway versatility is needed you have slow gears offered by deep reduction range. Also this 15-speed has 10-speed conversion that has no deep reduction range (gears L1-L5 & RLL). It suits to older trucks with linehaul or medium duties. This 10-speed is not so simple as previous 10-speed conversion but it’s still very compact and offers better and very realistic ratio set. Both lego conversion and older close ratio 10-speed Fuller are identical with 15-speeder’s low and high range so you can compare ratios from picture Ratio comparison 15-speed by ignoring gears L1-L5 & RLL. Also this 15-speed has a long multi-piece axle from auxiliary to main gearbox. So under high load is possible that axle bends too much and middle gear pairs lose their mesh. If problem occurs check picture High torque kit for fine tuning. F.5. More about 15-speed transmissions: In real world 15-speed transmission is enlarged version of older 10-speed close ratio linehaul and medium duty transmission. 15-speed gives versatility for on/off highway situations by giving slow gears without losing small gear steps of close ratio 10-speed. This versatility comes handy when you need to drive slow and speed up and slow down very often. In certain speed changes you end up to change range all the time and 15-speed transmission prevents this range shifting in two ways. While 1st gear (in low range) is not slowest gear you can have smaller gear steps and overall gear ratio so low range is faster than in wider ratio 10-speed transmission. So you can drive a little bit faster without changing to high range. Other thing is overlapping deep reduction and low range so there is a large speed range where you can choose either deep reduction or low range. In very rough situations you can drive with deep reduction range and on easier terrains with low range and have lots of speed changes without need to change range. On the other hand, if you can skip gears you there is a completely different approach you can try. You can do easy button shifts without using main shift lever by shifting between low and deep reduction range (for example L3-3). If you can use this larger gear step and need only two gears there is quite large speed range where you don’t need to shift main gearbox at all: just choose suitable move off gear in deep reduction range and drive with same main gear in low range. Three ranges give also three reverse gears: two slow and one very fast. Eaton’s modern 10-speed transmissions has also very fast high range reverse gear but in 15-speed transmission (and older close ratio 10-speed) high reverse is even faster. Too complicated? Here is simplified using idea: -On highway 10 speeds with low range (gears 1-5) and high range (gears 6-10) with simple operating -Off highway 5 speeds with deep reduction range (gears L1-L5)
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