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Ari Holopainen / tractor2 | |
| T. Tractor Transmissions Part II: Here is tractor transmissions part II. For universal tractor info check beginning of the previous section S. Tractor Transmissions Part I. T.1. 12+3R-speed, overall gear ratio 39,68: Original setup: 4-speed main gearbox + 3-speed range Alternative setups I & II: 3-speed range + 4-speed main gearbox Inspirer: Lamborghini Rekord 75 (TractorData)
“If anyone of you have 12 gears in your Lamborghini raise your hand. So, you are Italian farmers, right?” Lamborghini Rekord is not a super car, it’s a small tractor. :-) Its transmission contains 12 forward and 3 reverse gears and it’s done by 4-speed main gearbox with reverse gear and 3-speed range unit with ranges low (L), medium (M) and high (H). Available is three lego setups. In original setup main gearbox is before range unit but in alternative setups they are located vice versa. Idea in alternative setups is that you hide seldom used range unit into tractor’s engine bay with lego motor and locate more used main gearbox into cabin. In alternative setup I you get lego motor centered if you use Mu(20)-Mu(20) or S(16)-M(24) gear pair as pre ratio (move 1,5 studs right and 2 studs down from motor to range input). Alternative setup II is upgraded version of alter I with two changes: 4th main gear uses new 20 teeth double bevel clutch gear and reverse gear’s XS(8)-XS(8)-XS(8) gear train is replaced with XS(8)-S(16)-XS(8) due to relocation. These improvements give simpler and two studs shorter design so this alternative setup II recommended setup for lego builders. And you get lego motor centered by adding XS(8)-XS(8) gear pair between motor and input axle under front Su(12)-Mu(20) gear pair. You may notice in lego design that main gearbox is not the simplest structure and its gear steps are not geometrical. Ratios are chosen so that gear steps are close to Rekord’s ones. Despite the complexity this lego transmission is still quite compact design. While gear steps are quite large and ranges overlap only a little this transmission has large overall gear ratio. So you can call the lowest range as creeper range. And like in typical tractor transmissions ratio of the reverse gear is near to ratio of 2nd forward gear. Check picture Speed comparison. And as unnecessary note if you want to build Lamborghini Crono tractor you can check later chapter T.7. 15+15R-speed. T.2. 6+2R-speed version II, overall gear ratio 12,00: Main gearbox + range Inspirer: Ford 3600 (TractorData)
This 6+2R-speed version II is tractor transmission inspired by old Ford 3600. It has 3-speed main gearbox with reverse gear together with range unit. Design seems to be quite basic but we need to take a closer look.
Gear steps in main gearbox are large which means that you can start in high range for transportation even when need to move off on difficult terrain. But the greatest idea in this transmission is swapped 3rd and 4th gear in shift pattern. This swap creates smaller gear steps in middle gears to help working speed control. So there are as much as four gears of six that suit to field working speeds 4-12 km/h. 1st gear is for low speed operation and 6th gear for transportation. All in all this is quite versatile transmission for farm tractor despite the fact that it has only six forward gears. You can notice that lego design is not the simplest and smallest. Reason for complex design is that ratios and shift pattern are copied from real Ford’s transmission. For simpler design check earlier basic 6+2R-speed version I (inspired by old Massey Ferguson 150) or later 6+2R-speed version III (inspired by old Valmet 602). It needs some attention to get simple shift levers for both main gearbox and range unit. One example is available in YouTube clip Building example. T.3. 12+4R-speed version III, overall gear ratio 20,00: Main gearbox + range Inspirer: Ford 4430 (TractorData)
This 12+4R-speed version III (12-speed tractor version VIII) is not a cousin of earlier 12+4R-speed designs but big brother of 8+4R-speed transmission. It contains 4-speed main gearbox and 4-speed range unit with ranges high (H), medium (M), low (L) and reverse (R). So now there is reverse range with four main gears, not one reverse gear in four ranges. Reverse range is about as fast as medium range.
Ratios of lego transmission follow quite accurately Ford’s transmission. Main steps vary quite a lot so that steps 1-2 and 3-4 are 1,60 but step 2-3 is only 1,25. This design sounds weird but there is clever logic behind it. Those larger steps ensure that speed range in reverse is high enough. They also help to move off in high range while gear H1 is slower. But clever idea is in overlapping ranges: for example gear M1 fits right between gears L3 and L4. When you sort gears by ratios you can see there are good small gear steps in middle gears through whole speed range, only steps L1-L2 and H3-H4 are larger. This gives good selection of gears for working speed control. Check table Ratios sorted in picture Ratios. This transmission uses same idea of overlapping ranges as John Deere’s 16+16R-speed transmission. All in all lego design is narrow and not very long for being an inline setup. One possible issue can be efficiency problems in some gears. 4th gear in main gearbox is overdrive in which used gear pair S(16)-XS(8) can be problematic. And in range unit low and reverse range has ratio 2,50 after synchro parts which means fast spinning clutch gears S’(16C) when higher ranges are used. So, if this transmission doesn’t fail efficiency test drive it’s quite good choice for lego builders. This lego transmission is inspired by Ford 4430 but same tractor has also been sold as New Holland and Fiat. T.4. 6+2R-speed version III, overall gear ratio 8,33: Main gearbox + range Inspirer: Valmet 602 (TractorData)
This 6+2R-speed version III is another simple and compact tractor transmission, this time inspired by old Valmet 602. Design has again 3-speed main gearbox with reverse gear plus range unit. Main gearbox and range unit are parallel, and two transmission driving rings on the left belong to main gearbox and last one on the right to range unit. My goal was to design realistic lego transmission including real shift pattern and ratio set but it turned out to be very small and simple lego design as well.
Like in 6+2R-speed version II we need to notice that 3rd and 4th gear are swapped in shift pattern. There are two reasons for that. First advantage is slower starting gear in high range so you can start transportation even on rougher terrain without need for range change. But major reason for this swap is smaller gear steps in middle gears so you can squeeze as much as four gears suitable for field working speeds 4-12 km/h. So 1st gear is for low speeds, gears 2-5 for major working speeds and 6th gear for transportation. So, if you fancy simple and compact lego transmission for old tractor this one is very realistic design to use for. T.5. 18+6R-speed & 24+6R-speed, overall gear ratios 13,89 & 55,56: 18+6R-speed: 3+R-speed auxiliary + 6-speed main gearbox 24+6R-speed: 4+R-speed auxiliary + 6-speed main gearbox Inspirer: Deutz-Fahr DX 86
These 18+6R-speed and 24+6R-speed tractor transmissions are inspired by Deutz-Fahr DX 86 but design is related to basic 8+4R-speed which contains 4 main gears plus ranges high, low and reverse. Now we have more gears in both auxiliary and main gearbox: 18+6R-speed has 6-speed main gearbox with ranges high (H), medium (M), low (L) & reverse (R). 24+6R-speed is otherwise same design but it has additional creeper (LL) range. 18+6R-speed is new design but 24+6R-speed is remake with several improvements. Remade 24+6R-speed has smaller design, better ratio set and accurate shift pattern in auxiliary without possible efficiency problems made by large overdrive situations in some gears. Auxiliary’s shift pattern is really confusing but it’s copied from real Deutz-Fahr’s transmission. Earlier setups are still available on page Junkyard if you want to check them. In 18+6R-speed design lego motor and auxiliary can be located into 6 studs wide engine bay while 8 studs wide main gearbox is designed to locate inside cabin. 24+6R-speed design needs 8 studs wide engine bay in your lego tractor if only main gearbox fits inside cabin. In 24+6R-speed creeper range adds fifth position in shift pattern and needs many gear pairs in bottom layer due to high ratio so auxiliary needs more space than in 18+6R-speed. So if you can fit only 6 studs wide auxiliary into lego tractor’s engine bay your choice is basic 18+6R-speed but otherwise I recommend to use 24+6R-speed with all its goodies. These transmission setups concentrate on forward gears: After low range’s top gear (L6) you could shift direct to high range’s 1st gear (H1) but overlapping medium range gives versatility in driving in many different ways. For example you need less compound auxiliary and main gearbox shifts and there are more gears for field working speeds (4-12 km/h). And in front loader working you can choose suitable main gear and then use only auxiliary: for about same speed in both directions you shift between medium and reverse range and for slower forward speed than reverse speed you can shift between ranges low and reverse. But reverse gears are weak point in these transmission setups. Reverse range is slightly slower than medium range so there are only middle speed reverse gears. Lack of fast reverse gears is not a problem but especially in 24+6R-speed only creeping speed direction is forward. Usually creeper speeds are only needed in forward but lack of creeper speeds in reverse can be problem in this transmission. If you want creeper speeds also in reverse in your lego tractor I recommend to check below 15+15R-speed (basic 5x3), 30+15R-speed (forward gears splitted) and 45+45R-speed (3-speed powershift) tractor transmissions. T.6. 30+15R-speed, overall gear ratio 126,00: 5-speed main gearbox + 3-speed range + 2+R-speed split/reverse Inspirer: Deutz-Fahr Agroplus
This tractor transmission has 5-speed main gearbox, 3-speed range unit and 2+R-speed split/reverse auxiliary. So in this transmission reverse gear is combined with splitter, not with range unit like in earlier introduced 2+R-speed auxiliaries. Altogether you have 30 forward and 15 reverse gears in this transmission so in forward number of gears is doubled and gear steps are halved compared to reverse.
Available is now remake with much more compact design and simpler reverse gear. In original design sliding axle range unit adds too much length and width for easy lego tractor use. With some testing I found a way to relocate range unit so front part has only main gearbox’s width and parallel located range unit and split/reverse are not much wider. If you want to check original design it’s located on page Junkyard. Idea in this transmission is that you can split forward gears to get more accurate working speed control but in upshifting procedure splitting is not useful while you will need also difficult two stick shifts. So in upshifting you start with low split, shift first only main gearbox and as last upshift shift to high split. In reverse you have only main gear steps but 15 reverse gears cover the whole speed range so you have also fast reverse gears. Range unit have not only low and high range but also creeper range and ranges don’t overlap which makes overall gear ratio very large and allows also very low speed driving. All in all this is pure mechanical tractor transmission which gives maximum number of gears without overlapping ratios. This transmission gives 45 different gears but you can still have more gears so check big brother of this transmission, later shown 45+45R-speed version II with 3-speed powershift. T.7. 15+15R-speed, overall gear ratio 120,00: 5-speed main gearbox + 3-speed range + shuttle Inspirer: Lamborghini Crono 75
This 15+15R-speed is quite basic tractor transmission with very large overall gear ratio. It contains 5-speed main gearbox, 3-speed range unit and shuttle (fwd/rev). This transmission is inspired by small Lamborghini Crono tractor but it’s also cousin of Deutz-Fahr’s basic 10+10R-speed (no creeper range), 30+15R-speed (splitted forward gears) and 45+45R-speed (3-speed powershift) transmissions.
This 15+15R-speed replaces outdated 45+45R-speed version I (3x5x3, range + main gearbox + splitter), which is moved to page Junkyard if you want to check it. Old 45+45R-speed has 3-speed splitter representing powershift but I already have lego powershift designs available. In 15+15R-speed splitter is removed but redesigned construction is also more compact than 45+45R-speed without splitter. While there is three transmission driving rings and clutch gears in a row in power flow this lego transmission has potential backlash problem, which means bad response when changing driving direction especially in low range gears. This 15+15R-speed lego transmission is quite compact but it requires 8 stud wide engine bay in your lego tractor. If that is acceptable this one is good choice for both small Lamborghini Crono and as universal tractor transmission with large overall gear ratio. If you fancy awful lot of gears for your lego tractor there are several transmissions available: With 3-speed powershift you can choose later shown Deutz-Fahr inspired 45+45R-speed version II or Valtra inspired 36+36R-speed. For pure mechanical designs you can check earlier Deutz-Fahr inspired 24+6R-speed and 30+15R-speed. T.8. 45+45R-speed version II, overall gear ratio 150,00: 3-speed powershift + 5-speed main gearbox + 3-speed range Inspirer: Deutz-Fahr Agroplus
Here is upgraded version of lego 45+45R-speed tractor transmission. This version II has true 3-speed lego powershift (Low, Medium and High), 5-speed main gearbox and 3-speed range unit (creeper LL, low L and high H).
Lego powershift is done by two motors and a planetary gear. For simple use you need extra forward-stop-reverse switch (pole reverser) and picture Wiring shows how to wire this switch, battery box and two motors together. Using this powershift unit is easy: you choose driving direction with battery box’s switches and powershift’s stage with that forward-stop-reverse switch (picture Battery box). For more information about this powershift you can check original C.7. 3-speed powershift for tractor version II in Planetary gears. Building tip: Leave small gap between planet carrier’s axle joiner and first gear wheel of main gearbox’s input axle. It’s possible while 8 teeth gear of motor 1 goes a little bit inside planet carrier. This is to prevent possible collision problems between planet carrier and idler gear of motor 2. So this powershift allows you to shift your lego tractor remotely while moving and under load. Although powershift covers only small speed range 5 main gears with 3 ranges give very large speed range where you can use these powershift’s small speed changes. In typical use you first choose desired speed range with main gearbox and range unit. (In real tractor you will need also main gearbox shifting when driving in high range.) When you move off powershift is in low and then you add more speed by shifting remotely powershift to medium and high. If driving resistance gets too high or you need to slow down a little you can downshift with powershift. So, all in all this transmission gives awful lot of gears with partial powershift and very large overall gear ratio. If you have two identical motors and forward-stop-reverse switch and you are going to build large lego tractor this transmission is one choice for you. To get more powershift gears with legos you will need 3 motors and 2 planetary gears like in later shown 30+30R-speed with 5-speed powershift. T.9. 36+36R-speed, overall gear ratio 57,14: 3-speed powershift + 4-speed main gearbox + 3-speed range Inspirer: Valtra T121 Classic
This 36+36R-speed transmission is inspired by Valtra and it has 3-speed powershift (Low, Medium and High), 4-speed main gearbox and 3-speed range unit (creeper LL, low L and high H). Lego design is close to previous 45+45R-speed version II but only 4 main gears makes design more compact. Available is long and narrow original setup and shorter alternative setup with parallel located main gearbox and range unit.
Basic use is that you first choose desired ratio with main gearbox and range unit to be used with powershift stage high. But you move off with powershift in low and then add speed with stages medium and high, remote shift design allows you to do this during driving. So, if driving resistance gets too high or you need to slow down you can simply downshift with powershift. Main gearbox and range unit allow very large speed range where these small step powershifts can be done. Again lego powershift is done by two identical motors and a planetary gear. For simple use you need extra forward-stop-reverse switch (pole reverser) and picture Wiring shows how to wire this switch, battery box and two motors together. Using this powershift unit is easy: you choose driving direction with battery box’s switches and powershift’s stage with that forward-stop-reverse switch (picture Battery box). For more information about this powershift you can check original C.7. 3-speed powershift for tractor version II in Planetary gears. For example there you can find enforced planetary gear for low speed motors. Building tip: Leave small gap between planet carrier’s axle joiner and first gear wheel of main gearbox’s input axle. It’s possible while 8 teeth gear of motor 1 goes a little bit inside planet carrier. This is to prevent possible collision problems between planet carrier and idler gear of motor 2. So, if you can build this powershift design, here is two quite compact and useful setups to build. Depending on your tractor design you can choose narrow inline design or short parallel design. T.10. 30+30R-speed, overall gear ratio 79,20: 5-speed powershift + 6-speed range Inspirer: Valtra N104 HiTech
This lego 30+30R-speed tractor transmission has 5-speed powershift and 6-speed range unit (ranges LA, LB, A, B, C and D). 5-speed powershift contains 3 identical motors and 2 planetary gear version III:s and is introduced in C.8. 5-speed powershift for tractor on page Planetary gears. So visit there for more info about this 5-speed powershift remake. You need a battery box and two forward-stop-reverse switches (pole reversers) to operate this system. Check pictures Ratios and Control unit.
This 30+30R-speed design is remake that replaces old 20+20R-speed with two improvements: 5-speed powershift is now in usable size and range unit has two creeper ranges. Original design is available on page Junkyard if you want to check it. But if you don’t need two creeper ranges and 20+20R-speed design is enough best way to build it is to combine C.8. 5-speed powershift for tractor remake (page Planetary gears) and A.4. 4-speed range unit for tractor (page Basic & special designs). Idea in this lego transmission is that you first choose suitable speed range with range unit. After move off you can enjoy powershiftable, remote controlled shifting with no need to stop for shifting and no H shift patterned shift lever. All you need is to choose driving direction with battery box’s switches and adjust speed with 2 switches. Idea for this transmission is taken from Valtra’s HiTech transmission which has 5-speed powershift, 4-speed range unit (optional equipment 2 creeper ranges) and powershuttle. It has no normal main gearbox or no shift lever with H shift pattern, all shifts are done by up & down buttons or automatic. When you change range while driving powershift shifts automatically most suitable powershift gear. You can choose automatic shifting even so that there is automatic shifting between ranges C and D, not only in powershift gears. There is also a driving mode in which you can adjust engine rpm:s where up- and downshiftings happen. I found these features in Valtra’s manuals but these are not all incredible features in Valtra tractors. All in all you can say today’s tractor transmissions are very hitech systems, not only just Valtra’s transmissions.
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