displacement in a master cylinder

[bobcat32]

I need help measuring the displacement for the of the master cylinder. I know the pressure input going into the caliper and the master cylinder. I tried equating the volume displacement of the master cylinder and the caliper, but I was getting .05", which is way too small.

[PatClarke]

pi r squared H

Pat

[bobcat32]

Is H the stroke distance because that is essentially what I used.

[PatClarke]

Yep, H is the stroke distance (or height of the cylinder).
Just basic math!

Pat

[bobcat32]

Alright, thanks

[bobcat32]

I should have clarified. I am actually looking for the stroke distance in the master cylinder. Do I just equate the caliper displacement with the master cylinder displacement?

[PatClarke]

Are you Indian?

Pat

[bobcat32]

no

[Buckingham]

but I was getting .05", which is way too small.

Why is it too small?

[onemaniac]

Originally posted by bobcat32:
I should have clarified. I am actually looking for the stroke distance in the master cylinder. Do I just equate the caliper displacement with the master cylinder displacement?

I strongly suggest that you actually read a book about brake system. Or even googling it will give you the answer. I'm no genius at designing brakes but the calculation you're looking for is the very first thing you should know. Go find a book and study.
If you want a quick answer just to put some parts together, you're in the wrong place. I honestly hate seeing some FSAE members just trying to build a car instead of trying to learn about design. It's a engineering design competition, so engineer and design!

[Kenneth]

Originally posted by PatClarke:
Are you Indian?

Pat

Yikes, I think that is out of line.


And when dealing with cylinders, don't forget to take into account for the volume the rod will take up.

[PatClarke]

And when dealing with cylinders, don't forget to take into account for the volume the rod will take up.

There is no rod volume on the working side of a master cylinder.

Pat

[Xeilos]

Bobcat:

Some more information regarding your setup is necessary.

-Sizing of MC Bore
-Sizing of Caliper bore
-Push/Pull type MC
-etc

If you do not want to share your numbers/information so we probably cannot help you. I would avail you to find Brake Handbook by Fred Puhn or a brakes book by Rudolph Limper(?).

[Owen Thomas]

I am actually going through the same process right now. The issue I'm personally having is deciding exactly how much my caliper pistons are displacing.

Assuming a negligible distance of the pads from the rotor surface (just rubbing) and an incompressible fluid, I'm guessing around 1mm total displacement(.5mm per opposing piston). If anyone thinks I'm out to lunch with this estimate please feel free to provide input.

[BMH]

Fred Puhn wrote a book about brake design, called the "Brake Design Handbook." I highly suggest you reading it before you get further along in your design. There are some other good brake design related books out there as well, so pick one, but the one by Fred Puhn is a good book and a good place to start (Its less that $20 bucks from Amazon if I remember correctly).

If you have questions after you read some literature for yourself, we will be happy to help you, however, at the moment, it is obvious that you need to do some more research.

Good luck!

[bobcat32]

Do you have any suggestions about any websites to look at? I have googled it but haven't really found anything useful

[Adambomb]

Here you go. It was the top result from google. It's for 9th grade math, so it shouldn't be too hard to understand.

Volume of a cylinder (http://www.mathsteacher.com.au/year9/ch14_measurement/18_cylinder/cylinder.htm)

[Big Mo]

Dont forget deflection of the brake pad...but good luck finding Young's...some companies don't like to share it.