# coupler max rpm?



## EVfun (Mar 14, 2010)

I am using this Ruland shaft coupler (CLC-18-18-F) on my EV Buggy. It has been subjected to dumping 120 volts worth of Optimas through a shorted controller into a Prestolite motor and survived. Ruland lists the maximum rpm as 4000 but I have had mine to 7000 without any issues.


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## rwaudio (May 22, 2008)

Newbiee said:


> Hi i am currently at the step in my conversion where i need to make the coupler. Looking over the forums for a while, i decided to go with the set screw coupling because of my specific application. However i noticed the specifications for these couplers say 4000 rpm max if they say anything at all. I purchased the fb1-4001 motor and am thinking the max rpms for this motor are a bit higher than 4000 and at 144v i may very well be using it past 4000 rpm so i am hesitant to purchase the coupler. The torque range specifications appear fine and i am wondering if the rpm range is truly a problem or if anyone knows where i can find a higher max rpm set screw coupler say in the 6000s? or is it just fine to use the 4000 rpm max couplers? i dont have any experience as you can see and am learning as i go
> if this link works this is the coupler i was planning on purchasing it is a bit expensive at 66$, i have seen some the same size for 15$ but without any specifications which worries me on the integrity, so all advice is welcome here!
> 
> http://www.grainger.com/Grainger/RULAND-MANUFACTURING-Rigid-Shaft-Coupling-2ARD7?Pid=search


I don't know about the RPM's however the rated torque is 100ft-lbs, I'm sure you could easily exceed that with with even a 500A controller. Be careful!


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## EVfun (Mar 14, 2010)

That is why I chose the split clamp type Ruland shaft coupler. It's rated for 360 ft-lbs of torque.


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## Newbiee (Feb 16, 2011)

i was looking at the split clamp coupler also, did u have any problems welding the clutch spline in it? the ft lbs of torque for the fb1 is more than 100 at 144 volts and 400 amps?


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## EVfun (Mar 14, 2010)

I did not weld the clutch spline into it. I used a VW Bus reverse gear, which has the same spline as the Bug clutch, and had it machined to 1.125 inches in diameter with a 1/4 inch keyway cut into it. 

Does your tranny have a pilot shaft sticking out past the clutch splines? If so, does it need to be supported? I know most RWD cars must have pilot shaft support as the splines alone are not tight enough to keep the front tranny bearing alive. I don't know much about transverse FWD transaxles (except the Rabbit didn't have a pilot shaft.) The VW aircooled Beetle doesn't require a pilot bearing, so I cut off that part of the input shaft to reduce coupler length.

The FB-1 motor makes 100 ft-lbs of torque at about 500 amps.


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## Newbiee (Feb 16, 2011)

Sorry i dont really know about the pilot shaft, i do know that the transmission shaft starts off splined and extends past the bell housing frame so i would need to cut the transmission shaft shorter. The tip of the shaft does not have the spline and that is where i will be cutting. I figured i have no choice to cut the transmission shaft shorter because the thickness of the adapter plate will not be enough to mate the motor and trans together without hitting shafts first. My car used to be an automatic, i picked up the manual transmission from the same car in a junkyard, so this is going to be clutchless, i dont have a 3rd peddle or a flywheel all i have is the clutch disk spline and my plan is to have it welded into the set screw coupler. Is all of this a bad idea?


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## EVfun (Mar 14, 2010)

I suspect that welding near the splines is a bad idea as it will remove the heat treatment that hardens them. If that happens the splines are likely to fail after a few thousand miles. 

You are talking about cutting off the pilot shaft. Since the 240 is a RWD car the pilot shaft is required and must be supported. Without that the input shaft is only located by a single bearing at the other end and that bearing will fail. The splines are not a tight enough fit to provide positive location. Of course you won't need a bearing, since you are clutchless, but it does need a snug fitting locating hole to essentially let the motors rear bearing locate that end of the input shaft.

What you had proposed is a bad idea, sorry. You are going to have to redesign your solution.


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## rwaudio (May 22, 2008)

It may cost a bit more than your cheap solution from Grainger, but I would recommend contacting Charlie at www.evcouplerconnection.com he designed a clutchless coupler for my 944 that has a brass bushing to center the pilot shaft of the transmission and it should outlast most other parts of the car. Definatially worth it in the long run.


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## Newbiee (Feb 16, 2011)

shucks.. would you be able to simplify that for me lol.
I got the idea from reading how a few other people do it, i will try to attach a picture i saved from the net of what i was trying to mimic. 
Also if i am not allowed to cut the transmission shaft shorter am i allowed to go further out of the "critical distance" i read about in bob brants book about the distance of the removed ICE engine to the flywheel that i am supposed to reproduce?


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## EVfun (Mar 14, 2010)

The "magic number" changes meaning somewhat if you are not putting the flywheel back in place. What you want is to make the back of the electric motor mimic the back of the gas engine. The first part of that is the adapter plate that allows you to bolt the motor to the transmission. Then you want to locate the clutch splines the same distance behind that face on your electric motor as they where on the gas engine. That way, when you bolt the motor and adapter to the transmission they clutch splines will be in their original location, which we already know will properly engage the spines on the transmission input shaft. 

You can certainly space the motor forward on the adapter plate to have room to put the clutch splines in the correct place and leave room for the pilot shaft. If you look at a lot of conversions out there you will notice that a spacer ring is very often a part of the adapter. Even in the picture you attached the motor is clearly spaced well forward.


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## Snakub (Sep 8, 2008)

What's wrong with going with the car's original clutch? I have direct drive right now but wish I had a clutch and I have purchased a mini clutch right now that I will be installing soon I think you will like the acceleration much better. Btw does anyone know if they sell a cvt transmission relatively cheap?Maybe there is some sort of conversion kit


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## Newbiee (Feb 16, 2011)

ahhh i get it thanks! good thing i did not purchase any coupler or adapter plate and cut off the transmission shaft already lol ouch thank goodness i spoke to you first! 
haha another question! for the pilot shaft you mentioned it needs a support still right? How would i be able to support the pilot shaft or how do others with similar setups support the pilot shaft? and the image i attached with the spline welded to the coupler is that a representation of what would probably fail after a few thousand miles?


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## rfhendrix (Jan 24, 2011)

Look at post #9 again. Charlie did a good job for me as well. The pilot bearing is supported by the coupler that Charlie (or whoever) makes for you. The coupler of course is supported by the motor and the motor is bolted to you adapter plate and the adapter plate (including the necessary spacer) is bolted to the transmission bell housing.


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## EVfun (Mar 14, 2010)

Newbiee said:


> for the pilot shaft you mentioned it needs a support still right? How would i be able to support the pilot shaft or how do others with similar setups support the pilot shaft?


Yes, the pilot shaft still needs support because the splines don't locate the input shaft tightly enough. This support is generally part of the adapter. For a clutchless setup I would recommend a coupler where the part that fits into the Ruland shaft coupler has a hole sized to fit the pilot shaft. The part that sticks out should have a small flange with a bolt pattern to allow you to attach the center section (splined part) from a clutch disc. This adapter can be machined out of aluminum (generally cheaper) because the pilot shaft doesn't rotate relative to the motor shaft and adapter. For a clutched adapter you would need to fit a bearing or Oilite bronze bushing for the pilot shaft to rotate against.


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## Coley (Jul 26, 2007)

Quote:
"I suspect that welding near the splines is a bad idea as it will remove the heat treatment that hardens them. If that happens the splines are likely to fail after a few thousand miles."

What I have found is that most clutch disc hubs are NOT hardened.
Welding mine didn't harm it at all.

After 13,000+ miles it shows no wear.


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## Newbiee (Feb 16, 2011)

Ok Evfun thanks so much i think i have an idea of what you are talking about now lol. 
For the clutch-less model which is what i have to make do with because of the circumstances, does the hole for the pilot shaft in the adapter piece between the coupler and the clutch disk spline need to be very tight on the pilot shaft right.. oh i think you mentioned that earlier! so now all i have to do is get these measurements for this new coupling and bring them to a machinist right? also i am not experienced with anything ev or automotive im still very young -_- 
so for the set screw coupler i notice from the pictures on grainger they have 2 set screws on the top, are both of those set screws supposed to land on the electric motor's shaft or only 1 on the motor shaft and 1 on the adapter in between ? it seems a bit weird that the motor shaft is less than 2" and the coupler is 3" and that both of those set screws would land on the motor shaft!


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## Coley (Jul 26, 2007)

Only one for the motor. One for the input shaft.


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## EVfun (Mar 14, 2010)

Newbiee said:


> does the hole for the pilot shaft in the adapter piece between the coupler and the clutch disk spline need to be very tight on the pilot shaft


It should be fit like the bushing would. It shouldn't actually be tight because any time you have something suspended between 2 bearings one of them needs to allow for slight length changes that are a part of heating and cooling. The hole will be a few thousandths of an inch larger than the pilot shaft.


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## Newbiee (Feb 16, 2011)

I notice that the pilot shaft and the splines on the transmission shaft are a one piece combo so they turn together, does this change anything?


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## EVfun (Mar 14, 2010)

No, that's normal. The splines don't fit tight enough in the clutch disc hub to stabilize the input shaft. They are designed for a rather sloppy fit to allow very free movement without lubrication. The pilot section is there to support the input shaft.


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## Newbiee (Feb 16, 2011)

OK here is my new plan hahaha.. btw EVfun you are my best friend lol im really sorry for all my annoying noob questions i threw at you i really appreciate your help! Thanks Coley too! you are a legend!

i will buy the pilot bushing from oreilley auto parts for $2 and cut a hole in a piece of steel sized to fit that bushing in the center of the steel piece, and weld the bushing into the hole. Then weld the steel sheet with the pilot bushing center to the coupler (the thickness of the steel sheet will vary depending which coupler) and finally, weld the clutch disk frame to the opposite side of the steel sheet! here is a uhhhh drawing? lol is this dumb too?  only thing i find a bit weird is that the pilot shaft nose is 1.75" in length and according to oreilley auto parts the pilot bushing is only 0.689"  would the bushing by itself be enough support, or would i need to wrap the entire 1.75" ?


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## rfhendrix (Jan 24, 2011)

Cut the nose off to fit the bushing. It won't hurt anything, also it will bring your motor an inch closer which is good.


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## EVfun (Mar 14, 2010)

I doubt you will be doing any welding to the bushing. It is almost certainly made of bronze and won't weld (it will turn to liquid before the steel starts to melt.) Hitting bronze with an arc welder is one way to get rid of it!

You are going to have to machine this part. It needs to locate the input shaft accurately within a few thousandths of an inch. That is why the fit of the splines isn't good enough --to many thousandths of an inch of free movement. You could locate the input shaft with a hole in just a piece of 1/8 inch steel or aluminum because it isn't rotating relative to the rest of the coupler so it won't wear on this surface. For this same reason you may be able to shorten the pilot shaft some, however, since you have to retain at least part of it you may as well keep all of it and just have the motor spacer a little thicker. 

I would use a Ruland coupler (the clamp type that I used) and have an aluminum coupler machined to fit in it. The outside diameter of the one end would be 1.125 inch in diameter with a 1/4 inch keyway with an inside diameter that fits the pilot shaft. The other end of this would be a little larger in diameter with a locating ring and some threaded holes to fit the hub of a clutch disc while allowing it to be bolted on using the original rivet holes. Being small in diameter it should minimize shifting effort.


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## BandDButton (Oct 15, 2009)

The output shaft on a Warp 9 motor is drilled with a pilot hole. Does anyone know how deep it is?


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## Newbiee (Feb 16, 2011)

hmmm i am thinking that a machined aluminium coupler of 1-1/8 outside diameter inserted into a ruland coupler of 1-1/8 bore would transfer all the torque onto the 1-1/8th smaller coupler and i would go from 1200 in-lbs of capable torque from the ruland coupler of 2" outside diameter, to a much lower 240 in-lbs of capable torque because of a transfer of torque to a smaller coupler, (the 240 in-lbs i just took from a ruland 1-1/8th outside diameter coupler) but i am no engineer so please correct me!

I don't think i can afford to sacrifice a 100 ft lbs of capable torque so should i go with an entirely machined 1 piece coupler that i can just screw on the clutch disk to? It would have to look something like this, would a machinist build this for me if i gave him this schematic? Sorry i have never went to a machinist lol -_-


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## EVfun (Mar 14, 2010)

Huh?? I don't follow, "a machined aluminium coupler of 1-1/8 outside diameter inserted into a ruland coupler of 1-1/8 bore would transfer all the torque..." In my scenario it would transfer all that torque into the Ruland coupler CLC-18-18-F and that in turn would transfer it into the 1-1/8 motor shaft. This should all take the full torque the Ruland is rated for. 

The machined aluminum coupler is only a shaft at one end, the other end being the flange to attach the clutch disc hub. The pilot end of the transmissions input shaft could rest inside the Ruland coupler if it is the 5/8 inch diameter that your drawing seems to indicate. That leaves a 1/4 inch wall, less where the key is located, that makes me want to consider steel instead of aluminum.

I've used set screw hubs in a couple of my EVs, they can work just fine. It does allow you to machine the thing from a single piece of metal and not run through a Ruland coupler. Given an easy choice I avoid set screw hubs because they are generally not rated for the torque you can get from the motor (but once again, I have used them and so have many other people.) 

I could see your design being simplified with a 1-1/8 inch bore all the way through, with the 1-5/8 step at one end (for the clutch disc hub I'm guessing.) Then the pilot support would be a pressed in bushing, but it could be aluminum because it won't be functioning as a bearing in a clutchless design. That is similar to what the machinist suggested to me for the Datsun hub, the key difference is I was keeping the flywheel and clutch so the bushing had to be oillite bronze.

You would need to clean up your drawing a little and discuss it with your machinist. They often have recommendations based on what is easier to do (read, cheaper for you.) Plus, you need to make sure both of you understand what dimensions are key and what tolerances are allowed.


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## rfhendrix (Jan 24, 2011)

BandDButton said:


> The output shaft on a Warp 9 motor is drilled with a pilot hole. Does anyone know how deep it is?


It is about 2 1/8 inches from the face to the bottom of the threads. Only the bottom 1 1/4 of the hole is threaded leaving 7/8 un-threaded. This is on a new motor. I understand that the older ones are drilled differently.


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## Newbiee (Feb 16, 2011)

Lol you're right that does simplify things quite a bit! I drew a new model lol if you can see it, tell me if that is what you're referring to. And you're right again that step at one end is for the clutch disk hub, but don't worry the plan is to have it screwed on the coupler some how and not welded, that will be better also just in case i need to replace the spline i won't have to trash the whole coupler! I also made another step on the opposite end to fit inside the electric motors step so that way it wont grind on anything.


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## EVfun (Mar 14, 2010)

That looks like what I had in mind. I recognize the step at the motor end because the Datsun coupler has one of those too.  I added one additional small step to the step with an outside diameter 1.3 inches (inside 1.125 inches) so the coupler would rest safely against the motor's bearing race with no chance of the back face taking out the bearing seal. 

I like your idea of having an actual step to pickup up the clutch disc hub. Clutch hubs generally have a accurately centered step on one side because that is usually how they are located in the very center of the disc. No reason to hunt center down a second time if the clutch disc maker already did it for you.


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## Newbiee (Feb 16, 2011)

uhhmm i was just going to have the centre of the clutch disk hub land onto the centre of the transmissions spline. But i am probably wrong to do that again, what is the correct way or placement for the clutch disk hub on the transmissions splined shaft? basically how do i go about choosing where the clutch disk hub will land on the transmission's shaft lol. Does it have to be within some kind of specification?


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## Jimdear2 (Oct 12, 2008)

Newbiee said:


> uhhmm i was just going to have the centre of the clutch disk hub land onto the centre of the transmissions spline. But i am probably wrong to do that again, what is the correct way or placement for the clutch disk hub on the transmissions splined shaft? basically how do i go about choosing where the clutch disk hub will land on the transmission's shaft lol. Does it have to be within some kind of specification?


Newbiee,

If you are not using the clutch, just make sure that the clutch hub spline is fully engaged onto the transmission shaft spline. Beyond that no specific position.

If you are planning on using the clutch, the position is determined by the position of the flywheel, which MUST be located in the exact position in relation to the trans that it was in when still mounted to the ICE. 

Jim


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