Building my rally vocab
Posted by darkknight9
Kirk Coughlin Mega Moderator Location: Saint Paul, MN Join Date: 01/08/2006 Age: Possibly Wise Posts: 493 Rally Car: Dreaming of escorts and xrats |
Ted Andkilde Godlike Moderator Location: Windsor, ON, Canada Join Date: 04/30/2006 Age: Possibly Wise Posts: 329 Rally Car: 1968 Mini |
John Vanlandingham Junior Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
Eeeerr , no.
Here's from a place I go for fun answers: http://www.answers.com/topic/dog-mechanics?method=22 dog Wikipedia dog (mechanics) In mechanical engineering, a dog is a protrusion on a shaft or other component for the purposes of correct orientation and for transmitting torque. For example, a dog clutch is a means to couple two rotating shafts and is widely used in automotive transmissions. Some threaded engineering components have cutouts and are fitted with a wrench carrying matching dogs. An example would be the lockring on a fixed wheel sprocket for a bicycle. This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer) *************************************************************************** In short there are on the sude if a gear say 3-5-6 herking big blockie things sticking out the side, the gear is sitting on a sleeve or needle bearing and spins freely on the sahft it sits on. When you select a gear by moving the stick, eventually, somehow its trasmitted to a "shift-fork" which slides a matching "dog ring, which is internally splined and therefor sorta attached to the shaft, over which bashes into the "dogs" sticking out and as one or the other rotates, the slots in the side of the dog ring eventually line up, and the dog ring engages the gear and is drawn in by the rotational force. How drawn in should be your nezt question. The leading edge of the dogs are not square or perpendicular to the shaft, the have a slight undercut which can vary from "very nearly zero" to about 5 degree undercut on some boxes, say Japanese trailbike gearboxes. Don't got it? well stink of the opposite : if the dogs had leading edges which sloped away, when they engaged the squareish slots, they'd just slide apart. A little undercut and the rotation pulls them in, too much and you have to de-clutch too much and the shift is slow. So the "DETENT" holds the shift mechanism (shaft or fork or) in postition, which keeps the fork in the right place, the undercut keeps the gear locked to the hub which is splined to the shaft which now turns. Now the reason everybody yakks about them is is cause they WANT TO pretend like they "NEED" a box which they can do clutchless shifts so they can waste lots of time dragging their brakes in every fuckin turn and imagine they are driving "at 10/10ths, but 90% of the faster and easier shifts is from the fact that the actual gear ratios have, on 95% of dog boxes, much closer ratios, so the speed of ratation isn't a lot different and so shifts are quicker. My box is fairly close ratio: 2.45 first and 0.92 top and I use it synchro and it shift fast enough that some co-drivers have claimed they can only barely hear the shifts. But think of motorcycle trannies cause they are all dog boxes and by car standards, are all close, and if I think back to some of my moto-cross boxes, they started at about 2.2 for 1st and had maybe .86 for top and 6 gears between so very small steps, and thats why the shifts could be fast and low stress and the box last for eternity compared with shit boxes on cars. Here's perfect photo: 
Contrast that with: 
from: http://www.singster.co.uk/mascot%20mar-apr%202003%20(4).html This help? John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
Derek Bottles Professional Moderator Location: Lopez Island/ Seattle WA Join Date: 12/20/2005 Age: Possibly Wise Posts: 853 Rally Car: Past: 323, RX2, GTI. Next up M3 ? |
Kirk Coughlin Mega Moderator Location: Saint Paul, MN Join Date: 01/08/2006 Age: Possibly Wise Posts: 493 Rally Car: Dreaming of escorts and xrats |
Kirk Coughlin Mega Moderator Location: Saint Paul, MN Join Date: 01/08/2006 Age: Possibly Wise Posts: 493 Rally Car: Dreaming of escorts and xrats |
Eric Burmeister Elite Moderator Location: Michigan Join Date: 02/14/2006 Age: Possibly Wise Posts: 307 Rally Car: Mazdaspeed3 and Mazda Protege |
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