Topic: Caliper animation

[SohRon]

Every year we take off into the mountains for a week or so and live as primitively as possible. Seems like something semi-tragic manages to happen each time; once, while we were gone lightning hit the house and took out my computer, for instance.

Well this time I managed to break my foot (don't ask how    ), so I'm laid up here unable to move and wondering what to do. Seemed like the time to fool around with the computer, so I made this little gif file showing the action of the front caliper. I had a sectioned caliper handy, so I set it on the copier and got the basic shapes, then went from there. I hope you find it interesting, if not informative!

This shows the braking sequence from rest to full braking action. Note that the moving pad connects first which then forces the caliper to move, activating the fixed pad. Also, note that the piston seal distorts with the movement of the piston, then drags the piston back when pressure is released. The arrows indicate application and release of the brake lever.

All of the gaps and motions are exaggerated in this gif to make things a bit more clear; the total movement of the piston is actually in the .012" range, which would be hard to see in this vid. (EDIT: See post #18 below for a better version of this if you want a copy)

[TwoTired]

Nicely Done!

[dave500]

yeah bloody beautifull,now do a 550 transmission please.

[flatlander]

neat, and very clear!

[70CB750]

Great job!  Do you mind if I grab a copy?

[SohRon]

I have better versions available if you want a copy. Check back tomorrow and I'll try to post something.

Thanks to all for your kind comments.

[dave500]

do one of your broken foot,get better soon!

[75CBCafe]

I never realized that the seal acted as a return spring. Yes, very nicely done

[bwaller]

do one of your broken foot,get better soon!

Dave, you're a riot man!

I hope your foot heals quickly, are you wearing a "boot"?

[evanphi]

Nicely done!

[Stev-o]

At first, thought maybe you cut the caliper n half with your bandsaw (like the plug cap), this is much better.

Guessing the accident may be a bit embarrassing since you don't want to give details!

[Bob Wessner]

Nicely Done!

+1

Out of curiosity, what software did you use?

[754]

Nice, if that wont explain it, they will never get it.
 Can you get the rotor to turn slowly, or slow to a stop ?

[flybox1]

well played.  needs to go in the Brake FAQ section for sure.

[Powderman]

I never realized that the seal acted as a return spring. Yes, very nicely done

When I ran the caliper department at Rebco Racing Enterprises I built all the calipers with a square o-ring seal. When the racers complained about brake drag when the brakes got hot I would rebuild them caliper using round o-ring seals. The round seal allowed for more retraction of the piston eliminating the hot drag condition.The seal is the only thing that retracts the piston.

[TwoTired]

I never realized that the seal acted as a return spring. Yes, very nicely done

The seal is the only thing that retracts the piston.

The seal only does half the job of retraction.  The other half of the job is the caliper arm spring around the adjustment bolt and incidental contact of the rotor to the piston side brake pad.

I don't see how a round seal would work at all for retraction, unless it was deformed enough to form a square section.  Perhaps if a different material was used...

[754]

Dont think of it as a round seal, think more like double D shape.like a steering shaft in a car. Ie a shaft with a flat on 2 sides is an example

[brewsky]

Great job!
How about adding a little vibration and a loud screeching soundtrack to make it even more realistic?

[SohRon]

Thanks for the comments, guys, and for the sympathy for the foot. I'll try to answer your questions all at once.

Stev-o, you must have missed the part where I mentioned a "sectioned" caliper, which means I cut it apart - actually a couple of years ago, now. The bleeder screw was frozen solid and nothing I (or the guys down at the shop) did could free it. The shop crew offered to mill it out for me. but I decided (the caliper being from a "Box-O-Bolts auction on ebay - $25 for a box of parts) I'd just as well see how it ticks and so I hit the band saw. After all, my motto is: "If You Have Access To A Band Saw - Use It!"

As for the foot... Let's just say it involved a rock, a fire, and possibly just a smidge too much "Jackie Dee" and leave it at that...

Here's the original raw footage, so to speak:









I processed the scans and created the artwork in Photoshop, then exported them into Adobe's "Image Ready" to create the animation and .MOV files, then converted that to .GIF in AVS Video Converter. The rather poor video in the GIF is due to its limit of 256 colors. Here's a better version on Youtube:

CB Caliper

And theres a link at the bottom of this post you can use to save a version for your very own, if you're so inclined...

I thought about rotating the disc and showing the return spring... maybe I'll get to that in another version. I'm actually working on an essay covering the brakes; this is just kind of a test to see how the process works. Next up will be the Master Cylinder.

Now, where is that band saw?

[flybox1]

anyone notice during a cleaning that the o-ring groove is not square    cross section clearly shows it.
how about a nice closeup gif of the piston to piston o-ring interface, so all can see how it 'rolls up on edge' because of the off-square groove it sits in. 

[brewsky]

anyone notice during a cleaning that the o-ring groove is not square    cross section clearly shows it.
how about a nice closeup gif of the piston to piston o-ring interface, so all can see how it 'rolls up on edge' because of the off-square groove it sits in. 

+1...........you beat me to it....I thought I was not able to get the corners completely cleaned out!

[mono]

Well done!  seriously impressive

[flybox1]

anyone notice during a cleaning that the o-ring groove is not square    cross section clearly shows it.
how about a nice closeup gif of the piston to piston o-ring interface, so all can see how it 'rolls up on edge' because of the off-square groove it sits in. 

+1...........you beat me to it....I thought I was not able to get the corners completely cleaned out!

Yes. at rest, piston-facing side of the seal sits flush with the piston, with enough pressure to prevent leaks(good condition piston assumed), but when fluid pressure increases behind the piston and it moves, only the posterior edge of the seal rides/rolls up on the edge on the piston, increasing the pressure in the groove and tightening the seal.
good stuff.

[Bob Wessner]

A copy of the animation has been posted to the Brake thread within the FAQ's. Thanks, SohRon.

[Deltarider]

yeah bloody beautifull,now do a 550 transmission please.