# Coupler ideas?



## Guest (Feb 3, 2009)

Got a picture of your's. The Electric Lemon coupler is a damn good one. I have looked at that many times. Thinking of doing that for my Kostov to Buggy connection.


----------



## DIYguy (Sep 18, 2008)

Personally, I'm not a fan of a straight bore with key and set screw. I believe in taper locking. There is little to stop the movement/sliding. Also, if the original clutch used only 3 screws to connect, there should be no reason that this wouldn't work for your electric motor connection.... unless the torque is significantly more. 

I wanted to use the inner clutch with springs, but my design made that pretty much impossible... so... I just used the centre hub from the clutch and welded it up. I have details in my thread, I think RKM (Rob) did something similar also.

cheers.


----------



## JRP3 (Mar 7, 2008)

DIYguy said:


> Personally, I'm not a fan of a straight bore with key and set screw. I believe in taper locking. There is little to stop the movement/sliding. Also, if the original clutch used only 3 screws to connect, there should be no reason that this wouldn't work for your electric motor connection.... unless the torque is significantly more.


Here's where I see the problem. In the original application the 3 or 4 bolts, (actually rivets), are only there to hold the springs and spline together as a sandwich, the actual load is transfered from the spline, through the springs, to the clutch disk. In this design the rivets are replaced with bolts that are tapped into the motor hub, so now the force is transfered through the bolts. I guess I should check the torque rating for 1/4 inch bolts, I don't think there is enough material to bore out for larger ones. Another way to go would be to use all the small holes that the clutch disc was riveted to and use many small bolts. That would keep the springs in the mix as they were originally.
I also don't like the straight taper with set screw and would like to find a taper lock hub with flange to bolt to.


----------



## Twilly (Jan 22, 2008)

1 1/8th coupler + spline from center of clutch disk + a day at the machine shop = Coupler


----------



## ruspert (Jun 16, 2008)

JRP3 said:


> Here's where I see the problem. In the original application the 3 or 4 bolts, (actually rivets), are only there to hold the springs and spline together as a sandwich, the actual load is transfered from the spline, through the springs, to the clutch disk. In this design the rivets are replaced with bolts that are tapped into the motor hub, so now the force is transfered through the bolts. I guess I should check the torque rating for 1/4 inch bolts, I don't think there is enough material to bore out for larger ones. Another way to go would be to use all the small holes that the clutch disc was riveted to and use many small bolts. That would keep the springs in the mix as they were originally.
> I also don't like the straight taper with set screw and would like to find a taper lock hub with flange to bolt to.


The hub that connects to the motor shaft has 2 set screws 90 degrees apart. The splined hub is fastened solid to the center plate and coupled to the two outer pates through the springs. The motor torque is cushioned by the springs from the outer 2 plates to the center plate plate that transfers the torque to the transmission shaft.
I have made the same type of coupler.


----------



## JRP3 (Mar 7, 2008)

ruspert said:


> The hub that connects to the motor shaft has 2 set screws 90 degrees apart. The splined hub is fastened solid to the center plate and coupled to the two outer pates through the springs. The motor torque is cushioned by the springs from the outer 2 plates to the center plate plate that transfers the torque to the transmission shaft.
> I have made the same type of coupler.


But the motor torque is still transfered from the motor hub to the outer plates by the 4 bolts, (in my case 3 bolts), where in the original setup it's transfered through 16 rivets in my clutch. If I can find a large enough flange I could use those same rivet holes with bolts.


----------



## JRP3 (Mar 7, 2008)

Twilly said:


> 1 1/8th coupler + spline from center of clutch disk + a day at the machine shop = Coupler


That looks nice but I don't have access to a machine shop.


----------



## JRP3 (Mar 7, 2008)

Each flange actually has an extra hole that wasn't used so I could potentially have 24 bolts, which is probably overkill


----------



## piotrsko (Dec 9, 2007)

shear force to pop a 1/4 aircraft bolt is about 10,000 KSI. Those look to be grade 9 so the shear goes up to about 25,000 each. shear is different than stretch.

you have 3 so that gets to an ultimate of better than 30k, but I'm at a loss as to how much force is required on parallel plates to shear. I think we used to shear 1/4 cold roll in a 3 ton punch press. with the springs I don't figure you will be near to shearing anything. 

things to watch for: if a bolt elongates, because they are not in solid stock, it will aggravate the shear process. a spacer on the bolts where it attaches the adapter to clutch disk would help loads. get them really tight, and use a thread locker.

If it breaks, well, you weren't sure about it anyways. However, looks like a nice way to build it to me.


----------



## JRP3 (Mar 7, 2008)

The one with 4 bolts isn't mine, it's an example of what I was thinking of using. Mine is the one with 3 rivets, which would give me 3 bolts, but if your shear strength ratings are accurate would still be plenty. I'd hate to have it shear off in traffic though


----------



## piotrsko (Dec 9, 2007)

I amended my last post because of old age and old age. saw you said 3 after I said send. 3 should still work. punch it hard on the driveway first time out. if it don't break then, might never will.

try drilling between the other ends of the spring for 6, IMHO: overkill after 4.


----------



## JRP3 (Mar 7, 2008)

piotrsko said:


> try drilling between the other ends of the spring for 6, IMHO: overkill after 4.


That's not a bad idea as long as I can over size the holes in the center plate to allow room around the bolts so the center plate can still move when the springs flex.


----------



## ruspert (Jun 16, 2008)

JRP3 said:


> But the motor torque is still transfered from the motor hub to the outer plates by the 4 bolts, (in my case 3 bolts), where in the original setup it's transfered through 16 rivets in my clutch. If I can find a large enough flange I could use those same rivet holes with bolts.


 

In the normal ICE application, the clutch disk is fastened to one of the outer plates by the small rivets and the torque then is transfered from the flywheel to one of the outer plates and it is then coupled to the second outer plate by way of spacers and rivets that is then coupled through the springs to the inner plate that is fastened to the splined shaft which applies the torque to the transmission shaft. The outer plates are free to rotate to the limits of the springs in both directions. In the EV application, the torque force is being applied to the four bolts, but no more force than would be applied to the four rivets that the bolts and spacers replaced..


----------



## JRP3 (Mar 7, 2008)

Maybe I'm over thinking it but the way I see it the outer plate with the clutch riveted to it applies most of the load to the springs where they contact the plate, and the other outer plate is basically just along for the ride to hold the sandwich together. So main power transfer is clutch->outer plate->springs ->center plate->spline->trans shaft.
If you could imagine the outer plate and center plate staying together without the rivets and second outer plate the springs would still transfer the power between the two, without any rivets involved.


----------



## Coley (Jul 26, 2007)

I am still wondering why the sprung center is supposed to be used!

There really is no need for it. There is enough springyness in the rest of the drive train to take up any need for the clutch center spring setup.

An electric motor is smooth on the application of torque and it is steady torque.

An ICE on the other hand, has pulses from each cylinder's firing that makes the springs necessary.

A simple connector will do the job much cheaper and more reliable. NO bolts to shear etc.

The simple keyed motor end will stay where it needs to be without coming loose. Running a transmission, you only turn the motor in one direction.
How is this supposed to come loose?

The adapter I made is tough enough to run large machinery without a problem and cost almost nothing in comparison.

Why complicate a conversion.....


----------



## Twilly (Jan 22, 2008)

If you are planning on doing this without a machine shop, just keep this in mind... That coupler will be spinning at 5000 rpm... And the larger ( more mass ) you have there, the more likely you are to be out of balance. This can cause problems like premature wear on the motor and transmission input bearings and could cause the coupler to come apart.


----------



## JRP3 (Mar 7, 2008)

Coley said:


> I am still wondering why the sprung center is supposed to be used!


I need a spline to connect to my transmission, the clutch has one so I'd like to use it.


> There really is no need for it. There is enough springyness in the rest of the drive train to take up any need for the clutch center spring setup.
> 
> An electric motor is smooth on the application of torque and it is steady torque.
> 
> An ICE on the other hand, has pulses from each cylinder's firing that makes the springs necessary.


Actually I think the springs are there to take up the initial shock of clutch engagement and hard acceleration. I do agree that the springs are probably not necessary but I don't see a way to hook up to my transmission spline without a lot of machining.


> A simple connector will do the job much cheaper and more reliable. NO bolts to shear etc.
> 
> The simple keyed motor end will stay where it needs to be without coming loose. Running a transmission, you only turn the motor in one direction.
> How is this supposed to come loose?


Vibration and temperature changes can loosen the hold of the setscrew on the shaft, that's why taper locks were developed. I've had keyed hubs come loose in other applications even though they were thread locked.


> The adapter I made is tough enough to run large machinery without a problem and cost almost nothing in comparison.
> 
> Why complicate a conversion.....


I'm actually trying to keep it cheap and simple buy using parts I already have and trying to attach them to a taper lock hub. Most professional couplers use taper lock hubs, probably for a good reason.
http://ev-solutions.net/store/index..._id=14&zenid=cc2cbb09ef82643ddfd0ad96ed3f8eae
http://canev.com/KitsComp/Components/S10AdpKit.html


----------



## JRP3 (Mar 7, 2008)

Twilly said:


> If you are planning on doing this without a machine shop, just keep this in mind... That coupler will be spinning at 5000 rpm... And the larger ( more mass ) you have there, the more likely you are to be out of balance. This can cause problems like premature wear on the motor and transmission input bearings and could cause the coupler to come apart.


Good point.


----------



## piotrsko (Dec 9, 2007)

my $.02 (again needed or not)

Lately, they stuff I am getting out of "precision" machine shops could be beaten by an amateur with a dull bit and a center punch.

shove a broom handle in it, pace it on a level, flat parallel set of uprights and balance it by drilling the coupling's heavy side.

if the clutch hub is apart, should be easy to make the extra spring holes larger.

BTW the springs also allow for a slight (<.010) mismatch between the theoretical shaft centers.


----------



## JRP3 (Mar 7, 2008)

piotrsko said:


> Lately, they stuff I am getting out of "precision" machine shops could be beaten by an amateur with a dull bit and a center punch.
> 
> shove a broom handle in it, pace it on a level, flat parallel set of uprights and balance it by drilling the coupling's heavy side.


Sounds like my kind of machine work. I'll see what I can come up with.


----------



## JRP3 (Mar 7, 2008)

Coley said:


> The simple keyed motor end will stay where it needs to be without coming loose. Running a transmission, you only turn the motor in one direction.
> How is this supposed to come loose?





> We do not use setscrews. Setscrews hubs will fail catastrophically, regardless of Loctite. Heatshrink fit hubs are nearly impossible to position with the necessary accuracy, and nearly impossible to remove once in place.


http://www.electroauto.com/catalog/adaptors.shtml

I've heard others say similar things so I'm not comfortable with setscrews.


----------



## Coley (Jul 26, 2007)

If your key and sprocket/adapter are fit properly and have a couple set screws, there is a stronger bond than the taperlocks that do not always run true.

Machinery with a lot more torque, than we are involved with in our EVs, run for years and not have a problem. 

But that is only my 50 years of machine/mechanical work experience......


----------



## JRP3 (Mar 7, 2008)

Coley said:


> If your key and sprocket/adapter are fit properly and have a couple set screws, there is a stronger bond than the taperlocks that do not always run true.


 Well that's not really a fair comparison, a properly fit unit verses one that is not. I do agree that whatever the product it has to be properly fit. I found this thread which is relevant: http://www.diyelectriccar.com/forums/showthread.php/taper-lock-bushing-info-25113.html
I wonder if they've continued the testing? I'll check.


> Machinery with a lot more torque, than we are involved with in our EVs, run for years and not have a problem.
> 
> But that is only my 50 years of machine/mechanical work experience......


I appreciate that experience and I too have seen straight keyed shafts work fine for years. I'm sure it could work fine in my application, but I'm not sure it's the best setup. I'm not the only person who thinks taper locks are a better solution and I'm trying to find out if that's accurate or not.


----------



## DIYguy (Sep 18, 2008)

Coley said:


> If your key and sprocket/adapter are fit properly and have a couple set screws, there is a stronger bond than the taperlocks that do not always run true.


I would disagree with this statement. The industry standard for rotating items like sheaves, pulleys and sprocket connections is taper lock. BTW, most taper lock bushings also employ a set screw onto the key itself. The force of one or more set screws on a through bore, cannot be compared to the lock that can be achieved with a taper lock bushing arrangement. Yes, three screws are better than two, and the tightening method is also important. Connections that are subject to vibration and repetitive load/unload particularly with shock, as well as significant temperature changes benefit from the added fastening capability of a taper lock bushing and hub.

Hey, it's a free country.... use whatever you like...  Just make sure YOUR shaft is secure...


----------



## Twilly (Jan 22, 2008)

I personally dont see the set screws as the issue... My coupler does not have anywhere to ge.... Even if I removed the set screws, the key cannot move in either direction, and the entire coupler cannot move more than a quarter inch. I will post a picture of the coupler taken from the clutch observation hole.


----------



## JRP3 (Mar 7, 2008)

Yes but even if it's only moving a quarter inch or so that means it's no longer tight to the shaft and spline, and that play of the moving coupler will eventually wear the spline and the shaft causing vibration and slop, possibly leading to breakage.


----------



## piotrsko (Dec 9, 2007)

OK the only issue I would have with your installation is whether or not the "woodruff key" is full length of the coupler or a bunch of short pieces. if it is full length, then in order for the coupling to have problems, the key has to remove itself the full length and bash about the bell housing. 

If you had to warm the coupling up a wee bit to get it to fit, even better, it might outlast the car it is in.

you bought a nice piece of keyway material and not 1/4 X 1/4 Home depot cold roll right?

once again, nice work. I don't forsee any problems


----------



## JRP3 (Mar 7, 2008)

Even with the key still in place you can't see a problem with the hub sliding back and forth along the shaft for thousands of miles?


----------



## Twilly (Jan 22, 2008)

It would not be good for the coupler to be sliding back and forth, but I still would not forsee a major problem. The coupler should be tight to the motor shaft, but the spline side was made to slide back and forth as you engage/disengage the clutch


----------



## Coley (Jul 26, 2007)

I can see where the coupling end on the motor should be tight and not move.

I have an inspection hole in my bellhousing and check the set screws at 2000 mile intervals. Nothing has come loose yet.

Now, what about the wear on the clutch hub center and the trans input shaft?

They are not tight and yet that is the other end of the connection.

I put a drop or two of oil on the chain connector and the clutch hub, in mine, @ 1000 mile intervals.

Not seen a clutch center wear out yet......on anything.....


----------



## JRP3 (Mar 7, 2008)

I don't want to ever even look at my coupler, I just want to "set it and forget it". I'll probably be checking it obsessively at first so I guess I better design some sort of inspection hole into the adapter, whatever I use. Apparently it all depends on machining and installation of whatever method is used:


> Manufacturing an accurate set screw style coupler still requires sound machining methods, but is easier than machining a taper. A good set screw style coupler is all about the shaft bore. We try to hold the shaft to bore clearance from .0003" to .0005". (that's three ten-thousandths to five ten-thousandths of an inch) Any tighter is pushing an interference fit, any looser is well, just looser. It can be cut close with either an indexable drill or a boring bar, but the final sizing has to be done with a reamer. Pretty standard machining.
> 
> So back to my opinion. I think both styles will work great if care and attention is paid to manufacturing methods as well as installation. I know that the most carefully machined taper lock can easily become a wobbler if it isn't installed very carefully and then tested. I also know that an "easy to install" setscrew style coupler can possibly fail if it's not machined to exacting tolerances. Personally, I think the setscrew style coupler is simpler, and that's mostly what we've been producing lately.


http://www.diyelectriccar.com/forums/showthread.php/taper-lock-bushing-info-p100583.html#post100583


----------



## slurryguy (Dec 16, 2008)

DIYguy said:


> I would disagree with this statement. The industry standard for rotating items like sheaves, pulleys and sprocket connections is taper lock.


I'm not trying to be a pain in the butt. I can see the value of using taper locks...however...

It seems to me that if we are going to discuss "industry standard" that we should look at how these types of motors are typically coupled in industry applications. FORKLIFTS! More forklifts in one average state use these types of motors than probably all EV Conversions in the entire United States combined. (No... I don't have the data to back that up, but I bet I'm right.)

I confess that I'm not an expert, but with the hundreds of different conversions I've been reading about, I've never seen ONE forklift disassembled that used a taperlock INSIDE THE FORKLIFT on the motor. NOT ONE! I've seen a lot of ripped apart forklift pictures in my reading. While there may be some out there that I haven't seen, it appears that taperlocks on motor shafts are very very rare inside forklifts.

I don't have data to prove popularity, just my subjective impressions based upon internet reading, but Forklifts seem to like the splined shafts the most. Keyed shafts are a popular second.

Transmissions on cars like splined shafts almost exclusively. If a transmission input shaft isn't an industry standard, what is for this application?

My point is that industry standard in the type of application we are discussing, is SPLINED shafts.


I understand why splined shafts are a pain in the butt... it's difficult and expensive to machine an adapter with splines in it to match a splined motor shaft. (unless you have an appropriately splined donor hub of some kind to start with.) This is particularly impractical for most DIY builds. I get that. I also realize that most EV specific motor manufacturers don't supply spline shafted motors probably for this exact reason. 

All that said, (and I've rambled more than I intended to), even if splined is more "industry standard" than anything else, (and in my humble opinion it is), the motor being used for the particular coupler being designed in this thread doesn't have a splined shaft, so it's a moot discussion and I just wasted a bunch of text and bored everyone with a pointless argument.

My apologies.... back to your regular programming. I'll shut up now.


----------



## JRP3 (Mar 7, 2008)

The following is exactly what concerns me:


> One piece of advice-put a spacer on the transmission shaft so that the coupler can't slide toward the transmission. No matter how tight you get the set screw on the motor shaft, it will slide toward the tranny. I got the first coupler repaired by Wildy ev, the second one cost $365. They both slid up and sheared the splines within a month.


http://www.diyelectriccar.com/forum...lled-my-wilderness-ev-motor-righti-23816.html


----------



## peggus (Feb 18, 2008)

For what it's worth: 

I've been running that coupler pictured in the first post for a couple of weeks now. I haven't sheared the bolts despite punching it as hard as my Curtis controller will allow. I did calculate the shear forces and came to the conclusion that there is plenty of margin, though I am not an ME.

I have no idea how it will hold up in the long run. I'll let you know if it fails.

There is a spacer between motor shaft and transmission shaft that prevents the coupler from sliding more than a 1/4 inch if the set screws come loose. The spacer also centers the transmission shaft.

I built it that way because I have access to a lathe and mill but no welding equipment. The springs cushioning the torque in the coupler may not be needed but they can't hurt much either, Fiat transmissions are not exactly known for their robustness.


----------



## rsisson (Feb 5, 2009)

Odd question...is there ANY chance that the holes in the clutch plate would line up with a STOCK taperlock hub adapter? That would just be too easy?

I may go out a find a used clutch for my target vehicle (I don't need the friction plate after all) and see what the spacing of the holes are...

That would be just too easy...

PS..in case you have any info, my target is a 1999 Toyota Corolla....


----------



## DIYguy (Sep 18, 2008)

slurryguy said:


> I'm not trying to be a pain in the butt. I can see the value of using taper locks...however... no pain here.... let's see if we can clarify the differences...
> 
> It seems to me that if we are going to discuss "industry standard" that we should look at how these types of motors are typically coupled in industry applications. FORKLIFTS! More forklifts in one average state use these types of motors than probably all EV Conversions in the entire United States combined. (No... I don't have the data to back that up, but I bet I'm right.)
> 
> ...


 No apologies required...it's all good...


----------



## JRP3 (Mar 7, 2008)

Interestingly enough, the Solectria/Azure AC55 uses a splined shaft with a taper lock hub, not sure how that works 








http://www.electroauto.com/catalog/acmotors.shtml


----------



## the gas wizard (Apr 19, 2008)

i just used a clutch centre with 6 cap screws and it was then pressed into the solid coupler. it works a treat. i'll post a vidoeo of it on youtube tomorrow at

http://www.youtube.com/user/lpgas1


cheers
blair


----------



## JRP3 (Mar 7, 2008)

What's holding the coupler to the motor shaft? Is that a taperlock?


----------



## the gas wizard (Apr 19, 2008)

no just a straight keyway and grub screws. the coupler had to be warmed in an oven and to press it on though! it works awesome!


----------



## ga2500ev (Apr 20, 2008)

I just wanted to add to the discussion. A couple of guys over at ecomodder.com are doing a video series on building an EV. They have an excellent video on using lovejoy couplings:

http://ecomodder.com/forum/showthread.php/ev-dodge-neon-conversion-5869.html

My question is are there coupling adaptors for splined shafts. I have a motor with a splined shaft and a splined coupling. I'm trying to figure out if there are lovejoys with splined fittings that I can use with the motor.

Also any ideas on how to turn the clutch plate so that it can be inserted into the other half of the coupling?

Thanks for any ideas,

ga2500ev


----------



## the gas wizard (Apr 19, 2008)

hi, love joy couplers are a really really bad idea! the union between motor and g/box needs to be solid otherwise there is nothing supporting the nose of the gearbox input shaft. most gearbox's run a pilot of spigot bearing in the rear of the crank shaft of the ICE to support the input shaft. if you run a love joy/ dog clutch the electric motor can not support the input of the gearbox and you will have premature input shaft bearing wear!


----------



## JRP3 (Mar 7, 2008)

I wonder if that depends on the transmission used. My trans input shaft has no play in it that I can see and the shaft doesn't have the little machined end that would fit into a bearing, unlike others I've seen.


----------



## Carroll_1 (Dec 18, 2007)

JRP3 said:


> I wonder if that depends on the transmission used. My trans input shaft has no play in it that I can see and the shaft doesn't have the little machined end that would fit into a bearing, unlike others I've seen.


You are correct. In documenting about a dozen transmissions/transaxles over the last few months, at least 50% of the models don't utilize a pilot shaft or pilot bearing.


----------



## JRP3 (Mar 7, 2008)

Broken lovejoy coupler. He blames poor alignment due to mounting the motor to the trans in the car but I'd think if the adapter plate is made properly that should align the coupler no matter where you assemble them.

http://greencarvideos.blogspot.com/2008/11/electro-metro-coupler-broke.html


----------

