Creating a clutch activator

Thread Starter

pyroartist

Joined Oct 9, 2015
88
I'm looking for a small 12V powered device that will generate up to 80psi of hydraulic pressure. It will replace (or connect to) the foot operated hydraulic master cylinder in a typical standard transmission vehicle. Here is a picture of the device I am looking for, https://www.epartrade.com/product/70fd6e1b-eclutch-actuator-oem
but I cannot find anywhere to purchase something like this. I see that the electro-mechanical portion of this is rather small but I don't know what is in there.
It has to be controllable so you can engage the clutch slowly from a standing start yet it has to move rapidly too in the case of shifting gears. Would this be an electric jack screw operating a piston or a rotating motor operating a gear train and lever arm to the piston? Has anyone seen something like this? Would be nice to find one in a surplus store online but no luck yet. I did look at linear actuators at https://www.surpluscenter.com/Linear-Actuators/DC-Linear-Actuators/ and they have enough force and are priced well but they might be too slow. I have seen specs that say it should move fully within 200 ms. An alternative might be an actuator that pulls down the clutch pedal via a steel cable. That would allow normal foot operation. Thanks for any thoughts on this.
 

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shortbus

Joined Sep 30, 2009
7,940
You didn't say what make of car/truck you have. Does your vehicle already have a hydraulic clutch in it, almost all built from around the late 1990's have one. Does this still need to allow the foot pedal to work the clutch? Years ago I built a hand clutch for a guy but it was a manual clutch system. Instead of an electric motor and hydraulic master cylinder, I used a power brake vacuum booster to move the clutch throw out lever.

https://grassrootsmotorsports.com/forum/grm/push-button-clutch-grm-style-aka-home-made/16498/page1/

https://grassrootsmotorsports.com/forum/grm/making-a-push-button-clutch/59246/page1/

This guy has a few Youtube videos about using one from a new Jeep, this is just one of them;
 
I would imagine it is some sort of jack screw operating a piston. The motor itself is probably a brushless motor with some form of encoder to read position. I can't say for sure, but I would think Formula 1 cars, Ferrari, Lamborghini, and the like are where you would find something like this. The ECU would track where the clutch engages and only move the fork enough to make the clutch work plus a little to allow for wear, heat, or whatever other variables to account for. I know truck transmissions work along those lines and would think that a car type one would work the same.
 
I poked around online myself out of curiosity and found I really don't know where you would find something like your picture. My apologies for bad guessing. I do know there are forms of manual type transmissions that are automated versus a typical fluid driven automatic, but what I could find all looked to have all the details built in.
 

Thread Starter

pyroartist

Joined Oct 9, 2015
88
Thanks for looking. I am still searching myself. Found a promising electro-hydraulic actuator but the company website has no information on it so I have emailed them. The most difficult spec seems to be the speed. Most jack screw actuators are too slow. Ideas still welcome.
 

butch28

Joined Oct 14, 2020
12
i am a hydraulic engineer!
give the reason why you want to do the job and not do it by foot?
my guess is you can not push the pedal!
next give me how you will shift the gears is it on the floor or column?
i can show you many ways to do it! air or hydraulic
 

Thread Starter

pyroartist

Joined Oct 9, 2015
88
Thanks all for the comments. I did buy the performance car and as expected it has a "heavy" clutch pedal pressure because of the high performance clutch. However I have learned that I can actuate it smoothly with just a little practice. I have a weak left leg due to an old accident but it is working well enough if I concentrate on the task. The hardest part is slipping it slowly from a dead stop. If I am nervous, like at a traffic light with someone behind me, I sometimes stall it. But in general it is working out OK. I have received some detailed information from an installer of hand clutches for handicapped people. He told me that he is not happy with the ones on the market today. They are too slow and difficult to install. He also said they are only for light duty clutches such as found on basic model smaller cars.
 

shortbus

Joined Sep 30, 2009
7,940
Or switch to a twin disc clutch. They use two discs with a floater and a standard duty pressure plate to get the needed torque handling without a high pedal load. Many owners of new Mustangs are going to them.
 

Thread Starter

pyroartist

Joined Oct 9, 2015
88
Thanks. Never knew what a twin disc clutch was. So it doubles the friction area but keeps the plate pressure the same? Does it require a special flywheel or longer transmission shaft? I am having a hard time visualizing how this could work.
 

Thread Starter

pyroartist

Joined Oct 9, 2015
88
I just looked up a Yonka twin disc clutch and it says "Heavier than stock pedal feel and some chatter at low RPM are to be expected with all extreme performance clutches." So the pedal is still heavy? Is it less then single disc performance clutches?
 

shortbus

Joined Sep 30, 2009
7,940
Look at McLeod clutches. I don't know about the Yonka clutches. The very high end cars, McLaren's . Lamborghini's and such use them and don't think they would allow a high pedal load or chatter for their customers.

I'm assuming that the Yonka is fro racing only so probably has a full size disc and pressure plate, where one for a road car uses smaller lighter components. More on the order of what a twin disc in a circle track car uses.

https://www.mcleodracing.com/
 
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