West Coast Drive: Output "shifting" shaft

[Adam.garcia]

Alright, so I understand that if we do not want to use a stroke limiting spacer, the center distance should be >1/2". How much greater? And would it be possible to simply keep the spacing at 1/2"? The width of the teeth on the dog is .45", so wouldn't that allow the dog to fully disengage between strokes?

[AdamHeard]

As Travis touched on, we mechanically limit the motion of the shifting action by limiting how far the external shift block can move (the block threaded onto the cylinder that interfaces to the small internal shaft via bearings).

I have a personal obsession with trying to make things smaller, and doing this allows us to shave the maximum amount of length off the gearbox by reducing the space between the gears (where the dog is), and minimizing how much the cylinder sticks out in the rear.

[Adam.garcia]

Originally Posted by AdamHeard

As Travis touched on, we mechanically limit the motion of the shifting action by limiting how far the external shift block can move (the block threaded onto the cylinder that interfaces to the small internal shaft via bearings).

I have a personal obsession with trying to make things smaller, and doing this allows us to shave the maximum amount of length off the gearbox by reducing the space between the gears (where the dog is), and minimizing how much the cylinder sticks out in the rear.

I have very little experience with pneumatics, so this may be a fairly trivial question. But, from what I gather, when the piston is extended (or retracted) and hits a gear before it completely extends or retracts, the piston will remain locked into that position.

Adam. If the center distance is shorter than the stroke length, will a problem arise of the system jamming or the free spinning dog gears being pushed out of place?

What engineering thought should go into the dimension for those center distances?

[Cory]

Originally Posted by Adam.garcia

I have very little experience with pneumatics, so this may be a fairly trivial question. But, from what I gather, when the piston is extended (or retracted) and hits a gear before it completely extends or retracts, the piston will remain locked into that position.

Adam. If the center distance is shorter than the stroke length, will a problem arise of the system jamming or the free spinning dog gears being pushed out of place?

What engineering thought should go into the dimension for those center distances?

The system won't jam but you will greatly increase your odds of shearing the pin that links the dog to the shifter shaft.

[akoscielski3]

Originally Posted by Cory

The system won't jam but you will greatly increase your odds of shearing the pin that links the dog to the shifter shaft.

DO NOT SHEAR THAT PIN! they suck to get back in, or get one out (especially if it snapped inside). unless you have a tool to do it (we dont), and i have no idea if there even is a tool.

[Adam.garcia]

Since I'm just entering into Mechanical Engineering as an Undergraduate next year at UCLA, I am unfamiliar with the engineering principles and guiding formulas to test shear stress applied at certain conditions, and the shear stress that a screw (I'm thinking #4-40) will withstand before succumbing to failure.

Can anybody please enlighten me, or is this not worth calculating?

[PAR_WIG1350]

Originally Posted by Adam.garcia

Since I'm just entering into Mechanical Engineering as an Undergraduate next year at UCLA, I am unfamiliar with the engineering principles and guiding formulas to test shear stress applied at certain conditions, and the shear stress that a screw (I'm thinking #4-40) will withstand before succumbing to failure.

Can anybody please enlighten me, or is this not worth calculating?

screws don't like shear, also, 4-40 is rather small, the amount of shear force the cylinder would apply would be equal to the force the cylinder applies (as in all of the load applied to the screw by the cylinder are shear forces) so that would be (one half of the bore) squared times pi times the system gauge pressure

there may be some additional forces on the screw from the transmission itself, but the shaft should take most of this so it should be negligible.

NOTE: I believe in 2010 AM tried using screws in their shifters and found that they broke a lot more often then pins did.

[Adam.garcia]

Ahhh, yes, this is just simple physics. I was over thinking the problem.

Thanks