Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

H-pattern to sequential shifter

  1. Dec 29, 2011 #1
    Hi everyone, :smile:
    I am working on a project that involves converting H-pattern gear shifter(like any road car with manual gearbox) of Maruti Suzuki-800 into a sequential shifting system. I came up with a design that uses 4 linear hydraulic actuators to provide motion to the gear-stick in 2 perpendicular directions in a plane, thus, achieving the gear shifting. But now the problem is I can't use electronics to control the open/close sequence of the actuators, I only can control them mechanically. I can't think of any such mechanical mechanism to control them, please suggest some mechanism.
    You can also suggest an entirely different system for sequential shifting, but that should be purely mechanical.
    Waiting for advices...:uhh:
     
  2. jcsd
  3. Dec 30, 2011 #2
    http://www.ikeya-f.co.jp/en/product_notice/sequen_shifter.html [Broken]
     
    Last edited by a moderator: May 5, 2017
  4. Dec 31, 2011 #3
    Ya I can use their stuff but the thing is that all the professional sequential shifter makers use electronics in their shifters & the rules don't allow me to use any FLY BY WIRE. :cry: And if I'm not wrong most of these are for transmissions with 3 shifter rods but mine on the contrary has just one rod( which needs to be given in/out & rotary motion) as you can see in my previous post. Perhaps that's why I was thinking of making one rather than purchasing. But I don't have enough experience & knowledge to do it & need some guidance to design a completely MECHANICAL mechanism...NO electronics!!
     
    Last edited by a moderator: May 5, 2017
  5. Dec 31, 2011 #4
    Manual gearboxes and sequential gearboxes work in very different ways. You can't simply make a manual into a sequential without fundamental changes to the design. The gears are actuated very differently in the gearbox. (eg Three seperate rods and forks vs a barrel cam.)

    What you are suggesting in the OP is a fully mechanical robot that bolts on to the gear stick and does a manual gear change for you. From a driving aspect seems a total waste of time, money and effort. As you are increasing weight and complexity for no reduction in shift time, the lack of ability to skip damaged gears and you still have to manually control the clutch yourself.

    Basically lots of cons and no pros at all.
    It'd be much easier to fit a bike engine and gearbox, thus getting you a sequential shift (and probably more power than an old Suzuki Alto)


    Why are you trying to do this?
     
    Last edited: Dec 31, 2011
  6. Dec 31, 2011 #5

    turbo

    User Avatar
    Gold Member

    Ever seen Lenco trannies in action?

    http://www.bangshift.com/blog/Gear-Bangin-Video-Steve-Clukey-Pulls-Levers-and-Adjusts-the-Rear-View-At-140mph.html [Broken]
     
    Last edited by a moderator: May 5, 2017
  7. Dec 31, 2011 #6

    Ya it's bit difficult but I'm trying if anything can be done...someone told that it might be done with some ratcheting cams or drum..

    I am doing this for my car participating in SUPRA FSAE 2012...the rules forbid me to even look at the gearbox, leave alone making some changes in it & you are talking about changing the entire gearbox :eek:. I have to use the provided powertrain(with manual gearbox) of Maruti 800 as it is.

    Here's the shift pattern..
    http://www.acmejeepparts.com/Assets/Images/15445/15445-md.jpg

    & this is the shifter assembly..
    http://tis.spaghetticoder.org/images/1/02/24/56.jpg
    1=Shift arm 6=Support bearing (shift arm bearing)
    7=Shift lever
    2=Ball socket (shift lever bearing) 8=Shift rod
    3=Shift lever cover (gaiter) 9=Shift rod joint
    4=Shift lever knob 10=Bearing bush
    5=U-gaiter

    It has just one single rod instead of 3, so perhaps it might simplify the things..
     
  8. Dec 31, 2011 #7
    Then you'll have to come up with a mechanism that operates in two planes to "stir" the shifter to get a H-pattern shifting action from a single plane (fore and aft) motion.

    Easiest way might be to use somewhat the same principle that a motorcycle shifter uses (barrel cam). Cut a zig-zag groove (\/\/) in the barrel cam to operate the fore and aft action and another groove that steps to the side to move between the 1-2 and 3-4 gates. Use a ratchet to move the barrel cam. Maybe use a separate lever to operate reverse.
     
  9. Jan 1, 2012 #8
    maybe this is the kind of profile i'll be needing...

    http://img56.imageshack.us/img56/9871/seqextconversion8dg.jpg [Broken]

    of course its for a 6-speed gearbox & mine is 5-speed...i mistakenly said before that it was 4-speed :tongue:...but still the pattern is same..

    http://t1.gstatic.com/images?q=tbn:ANd9GcRf1GkZGkPg19yqZefrxcWtxabawqAyozHrH3PIOol_zIC5vqR0jhH5NLnixQ [Broken]

    however, I can't understand the ratcheting part...& if we go like 1/2/3/4/5 shifts..how to move in opposite direction..like 5/4/3/2/1 ??? is somehow the ratchet gonna reverse or what..:confused::confused::confused:
     
    Last edited by a moderator: May 5, 2017
  10. Jan 1, 2012 #9
    Last edited: Jan 1, 2012
  11. Jan 1, 2012 #10
    hey now I understood the ratcheting concept..the one like in bike gearboxes..but the last thing remaining in the design which I can't get is the one i stated in my previous post...HOW TO GET THE 2 PROFILES(RED & BLUE)..in graph from my previous post..ON THE SAME CAM TOGETHER & HOW THE 2 FOLLOWERS WILL BE CONNECTED TO THE SHIFTER ROD :confused::confused:..please just explain(if possible)with a drawing how can it be done...
    its the last thing to be done in the design..so can't wait.. :bugeye:
     
  12. Jan 1, 2012 #11
    To get both profiles on one cam all you do is take your graph of the two profiles and roll it into a cylinder. Several of the mechanisms in that last link have exactly that; have another look at this one:
    http://www.dansmc.com/suzy_re5_shifter.gif

    Part #4 is the barrel cam and shows three grooves on the same barrel; you only need two grooves.

    To get left and right motion (the red stepwise profile) you just need a lever that connects the groove in the cam on one end and the shifter on the other. The fore and aft (the blue zig-zag profile) isn't much different but would have a 90 degree bellcrank instead of a straight lever; that changes the direction of motion - and that's how you output two planes of motion from a single plane input.

    http://www.google.ca/imgres?imgurl=...8AT7COE6nv0gHr7JiBAg&ved=0CC0Q9QEwAQ&dur=1207
     
    Last edited: Jan 1, 2012
  13. Jan 5, 2012 #12
    the left-right movement gonna be easy, but although the bell crank would do the job for fore-aft movement...don't you think for every fore/aft movement..the lever(used for connecting the shifter & the cam for left-right motion) will also move fore/aft as its connected to the fore/aft moving shifter...& will part from the cam..how to deal with that?? splined hollow rod like in propeller shaft or something more easy & practical you suggest here...
     
  14. Jan 5, 2012 #13
    any ideas about how to calculate the radiator size needed for the cooling...mine is MARUTI 800---796cc, 37bhp @ 5000rpm, 3 cylinder petrol engine...
    i was thinking of installing 2 radiators on either sides of the car..
     
  15. Jan 5, 2012 #14
    Why do you want 2 radiators? One tiny, one will cool that thing.
    Pumping the extra water through the added plumbing will sap 99.9% of the total power of the engine.
    You could open the bonnet and blow on the block and it'd be sufficient cooling.

    In all seriousness, why not just look at the existing size of the radiator and look at it's rated cooling capacity.

    A lesson needs to be learned here as this is engineering.
    It's sort of the golden rule. Keep it as simple as you possibly can.
     
    Last edited: Jan 5, 2012
  16. Jan 5, 2012 #15
    funny!! :biggrin::biggrin:
    would it be enough if i use 2 bike radiators??...maybe honda cbr250r's...or any bike u suggest..:uhh:
     
  17. Jan 5, 2012 #16
    one more thing...if i install 2 radiators on both sides...would it be better to have pumping in both the radiators in parallel or series configuration??
     
  18. Jan 5, 2012 #17

    turbo

    User Avatar
    Gold Member

    Radiators work most efficiently when there is a large temperature differential between the coolant in the tubes and the air passing through the fins. If you go with series configuration, the first radiator will be the most efficient, and the second will be much less so. I haven't crunched any numbers, but intuitively, running them in parallel should put both of them to the best use.
     
  19. Jan 5, 2012 #18
    I'm not so sure about that, in theory yes, in practice testing is the only way to really know.

    I remember Mike had a single seater that had 2 radiators. We had a similar discussion back then, in the end I think they were plumbed in in series. flushed system with, deionised water and water wetter probabl make the biggest difference though.

    edit, found it:
    https://www.physicsforums.com/showthread.php?t=363502


    2 radiators are still majorly overkill for an 800cc engine that's putting out less power than a twisted rubber band. Overcooling is just as band as undercooling.
     
  20. Jan 7, 2012 #19
    someone plz solve this problem too..both the followers being attached to the same shift lever gonna move left/right or fore/aft accordingly with the other follower...how to deal with that???:confused:
     
  21. Jan 7, 2012 #20
    You could use a slot type arrangement that allows free movement in the other plane without losing the control in the desired plane. The splined shaft you mentioned would work as would a few other methods.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: H-pattern to sequential shifter
  1. He and H escape rates (Replies: 1)

  2. FET H-Bridge (Replies: 8)

Loading...