[cricketo]

This is just connected to a hydraulic pump. Busted off the teeth. Do a search for Lovejoy here on this site. It is very much recommended to NOT use them in an EV.

There seems to be a grainy structure in the break - are they made by casting ?

 

[57Chevy]

Definitely cast of some sort. Looks to be worth about $27.50.

The problem with rating a coupling on steady-state torque is that doesn't consider any resonant energy transfer between the driver and driven parts. If there is an exciting force that matches the natural frequency of the system then the peak loading could be many times the motor rating. A little bit of torque ripple at a critical frequency and broken coupling.

 

[sifawangiaEV]

The teeth of the love joy, 3 per side is a weak point as well as the rubber center. Constant stop and go will eventually cause the center rubber piece to be slowly crushed and as the gap increases the degradation happens faster. The teeth of the Lovejoy are also a shape that can fail due to fatigue of the edges. They are not designed for constant stop and go hard torque situations. They are designed for light duty or for constant speed and use. So a motor that is always moving without high torque applications constantly beating it to death will last much longer. I think you might be underestimating the power of the torque from these motors. Im sure some Lovejoy couplers might work but using the original vehicles means to couple things together with a clutch or auto trans is best. The solid couplers are best. I chose to use my VW's clutch and pressure plate. I'll be putting in two induction motors for a 167 hp and 173 ft/lb torque at the motor but much more at the wheel. I want to be sure it all holds together. My flywheel will have two clutch discs and a floater plate for the clutch so a stock pressure plate will suffice for the pressure and double the surface area of the clutch disk. 144v and up to 1000 amps combined.

I don't know any who actually had any long term success with them.

Thank you for your input. I see the problems with a Lovejoy being used on an on road vehicle and I definitely do not want to deal with that. I've come up with two alternatives after a bit of thought:

1) Remove the spider from an L150 Lovejoy coupler and have a machine shop weld the two parts together including filling in the middle so that it's just one solid structure. Would this work or no?

https://www.mcmaster.com/shaft-couplings/high-torque-set-screw-flexible-shaft-couplings-10/

2) I clicked on this link and found a coupler that works great with misalignment issues and is made for forward/backward and starting and stopping motion. It's also has a 2,075 lbs.-in torque capability and can go up to 9,000rpm. What do you think about using this coupler for my conversion? Is it up to take the abuse of an on road EV?

Out of option 1 and 2, which one do you recommend?

 

[onegreenev]

Question, Does your vehicle use a clutch? If so why are you so reluctant to utilize that and just get an adapter plate and coupler so you can bolt your flywheel to that and set it up as it was originally intended? I get you are trying real hard to save a buck or two. I get it. Shop around and look for good used parts from those that have abandoned a vehicle or have upgraded to better. I'd say no to both ideas. Unless your welder is top notch and can assure perfect alignment and a super solid connection then I'd say no and to afford someone like that defeats the purpose of saving a buck. Also I found out from my deep diving into building electric cars many slip on couplers or situations allow slop and it doesn't take much to start pounding away at things. It may run for a few years but will eventually pound out. A good type of coupler is a solid taper lock that can be really torqued down or better and interference fit coupler that must be heated before installation but it will be a one shot deal or you have to cut it off if you muck it up. They are the best and assure a solid connection from shaft to flywheel or transmission. I highly recommend using the vehicles stock clutch flywheel setup or auto transmission. Just being practical here. Im not a super fan of taper lock because they can be installed crooked but they can be removed and adjusted until you have it just right.

 

[onegreenev]

There seems to be a grainy structure in the break - are they made by casting ?

It is likely cast. Forged would be way stronger but they would also be very expensive.

 

[sifawangiaEV]

Question, Does your vehicle use a clutch?

I'm not using a clutch for this conversion, so it's going to be clutch-less.

Unless your welder is top notch and can assure perfect alignment and a super solid connection then I'd say no and to afford someone like that defeats the purpose of saving a buck.

I think I'll go to the machine shop and see if they can give me a quote for welding the Lovejoy together with perfect alignment and a solid connection because I think that this may be the best option.

 

[cricketo]

I'm not using a clutch for this conversion, so it's going to be clutch-less.

I think I'll go to the machine shop and see if they can give me a quote for welding the Lovejoy together with perfect alignment and a solid connection because I think that this may be the best option.

maybe I misunderstood the idea, but if you're welding the two halves together, isn't it easier just to machine a solid shaft coupler to begin with ?

To add, alignment on welded parts is never to machining tolerances. When a part is intended to be welded out of subcomponents, dimensions are left under/oversize to allow for finishing post-welding. So connecting two finished parts by welding is never a good idea.

 

[sifawangiaEV]

maybe I misunderstood the idea, but if you're welding the two halves together, isn't it easier just to machine a solid shaft coupler to begin with ?

It probably is but I have no clue how to do that and do it right at that. Do I just give the machine shop the clutch plate with and the motor shaft dimensions, tell them to make a coupling and leave it at that?

 

[onegreenev]

It probably is but I have no clue how to do that and do it right at that. Do I just give the machine shop the clutch plate with and the motor shaft dimensions, tell them to make a coupling and leave it at that?

So once you have it made please post pictures and then do what you will but after some time keep posting updates and if there is a failure please learn from it and post what happened so others don't have to do the same thing. But because others have done these sorts of things and the outcome was not so good it doesn't make sense that you don't listen to what others are saying. Many who do experience failures never post them. Oh well. I tried. My power of persuasion has apparently not been so good.

 

[onegreenev]

maybe I misunderstood the idea, but if you're welding the two halves together, isn't it easier just to machine a solid shaft coupler to begin with ?

To add, alignment on welded parts is never to machining tolerances. When a part is intended to be welded out of subcomponents, dimensions are left under/oversize to allow for finishing post-welding. So connecting two finished parts by welding is never a good idea.

I agree with you here. If you are going to do a solid coupler buy one for that purpose.

 

[cricketo]

I agree with you here. If you are going to do a solid coupler buy one for that purpose.

if these couplers exist and don't require modifications, I would recommend to the OP to do the same - buy one. Custom fabrication, including machining, is rarely cheaper than a part produced in numbers. The only way to get one cheaper than that is to have a friend who can make it, but even then their time is still quite expensive just donated.

 

[sifawangiaEV]

I agree with you here. If you are going to do a solid coupler buy one for that purpose.

I agree with that as well. I am asking how I can get one made. That's what my last post was asking. How can I get a solid coupler made? What do I need to provide the machine shop with so that they can make one? Please know that I am learning and I am very apt to change and persuasion because I am new to this. I have listened to what others have said which is why I am asking how I can do what is being recommended: get a solid coupler made specifically for my vehicle. Please let me know if you can help me answer this question and how I can get the job done right.

 

[cricketo]

I agree with that as well. I am asking how I can get one made. That's what my last post was asking. How can I get a solid coupler made? What do I need to provide the machine shop with so that they can make one? Please know that I am learning and I am very apt to change and persuasion because I am new to this. I have listened to what others have said which is why I am asking how I can do what is being recommended: get a solid coupler made specifically for my vehicle. Please let me know if you can help me answer this question and how I can get the job done right.

So others may be able to point you to an existing product. If you decide to have one made you have two choices - bring the parts that need to be mated to the machine shop, or sketch it up in CAD and bring them the drawing. If you draw it up in CAD you will be able to get quotes from shops that take orders online too.

 

[sifawangiaEV]

So others may be able to point you to an existing product.

Does anyone have a link to this existing product?

sketch it up in CAD and bring them the drawing. If you draw it up in CAD you will be able to get quotes from shops that take orders online too.

I think I might try my hand at making a CAD file of the coupler. I'll make a new thread for that and include the link to it here.

 

[sifawangiaEV]

I'm thinking of using an existing product for my coupling to make things more reliable and easier.
I made a new thread here: Finding a Good Coupler.

 

[cejota3]

First a caveat, I skipped probably the last 15 or 20 posts to just get to the end of this thread and add my 2 cents, so if this has already been settled or whatever, please excuse.

I highly recommend not using a LoveJoy coupling in (most) EV conversion applications. How do I know? Because I tried it myself, and it ended bad. I'll spare a lot of details, even though I know details matter in such things, but the long and the short of it is that LoveJoys are very good at lower RPMs and torque loads that rise gradually (relatively speaking). In real world conditions of an EV, you've got neither of those, and the pliable center "spider" just eventually gets chewed up. Additionally, the little bit of "play" that you get with a LoveJoy that is seen as one of its advantages in many of its applications turns out to not necessarily be to your advantage, again, in a typical EV conversion. You end up with unwanted unbalance. A solid coupling between your motor and tranny is most desirable. Think about it like this, if a LoveJoy-like connection was what was best between a motor and transmission, then automakers would have been using them (or again, something like them) for a long time now.

These I've found to be great:

Climax Part CC-112-112-KW Mild Steel, Black Oxide Plating Clamping Coupling, 1 1/8 inch X 1 1/8 inch bore, 2 1/8 inch OD, 3 1/4 inch Length, 1/4-28 x 3/4 Set Screw: Industrial Products: Amazon.com: Industrial & Scientific

Climax Part CC-112-112-KW Mild Steel, Black Oxide Plating Clamping Coupling, 1 1/8 inch X 1 1/8 inch bore, 2 1/8 inch OD, 3 1/4 inch Length, 1/4-28 x 3/4 Set Screw: Industrial Products: Amazon.com: Industrial & Scientific

www.amazon.com

(Not getting any kickback from Amazon or anything like that, this was just the quickest link I could find)

Good luck!

 

[brian_]

... the long and the short of it is that LoveJoys are very good at lower RPMs and torque loads that rise gradually (relatively speaking). In real world conditions of an EV, you've got neither of those, and the pliable center "spider" just eventually gets chewed up. Additionally, the little bit of "play" that you get with a LoveJoy that is seen as one of its advantages in many of its applications turns out to not necessarily be to your advantage, again, in a typical EV conversion. You end up with unwanted unbalance. A solid coupling between your motor and tranny is most desirable. Think about it like this, if a LoveJoy-like connection was what was best between a motor and transmission, then automakers would have been using them (or again, something like them) for a long time now.

There's no need for a compliant coupling between an engine and a transmission bolted to it, but in the propeller shaft (the drive shaft from a transmission in the front to a final drive in the back) many cars still use "giubo" or flexible disk couplings, which is like a traditional Lovejoy with the rubber part bolted to the yokes. It can work, but it's not a desirable thing, especially where compliance is not needed.

 

[sifawangiaEV]

First a caveat, I skipped probably the last 15 or 20 posts to just get to the end of this thread and add my 2 cents, so if this has already been settled or whatever, please excuse.

I highly recommend not using a LoveJoy coupling in (most) EV conversion applications. How do I know? Because I tried it myself, and it ended bad. I'll spare a lot of details, even though I know details matter in such things, but the long and the short of it is that LoveJoys are very good at lower RPMs and torque loads that rise gradually (relatively speaking). In real world conditions of an EV, you've got neither of those, and the pliable center "spider" just eventually gets chewed up. Additionally, the little bit of "play" that you get with a LoveJoy that is seen as one of its advantages in many of its applications turns out to not necessarily be to your advantage, again, in a typical EV conversion. You end up with unwanted unbalance. A solid coupling between your motor and tranny is most desirable. Think about it like this, if a LoveJoy-like connection was what was best between a motor and transmission, then automakers would have been using them (or again, something like them) for a long time now.

These I've found to be great:

Climax Part CC-112-112-KW Mild Steel, Black Oxide Plating Clamping Coupling, 1 1/8 inch X 1 1/8 inch bore, 2 1/8 inch OD, 3 1/4 inch Length, 1/4-28 x 3/4 Set Screw: Industrial Products: Amazon.com: Industrial & Scientific

Climax Part CC-112-112-KW Mild Steel, Black Oxide Plating Clamping Coupling, 1 1/8 inch X 1 1/8 inch bore, 2 1/8 inch OD, 3 1/4 inch Length, 1/4-28 x 3/4 Set Screw: Industrial Products: Amazon.com: Industrial & Scientific

www.amazon.com

(Not getting any kickback from Amazon or anything like that, this was just the quickest link I could find)

Good luck!

Thank you for the feedback! I decided that a LoveJoy coupling wouldn't be reliable but now I'm stuck between getting a rigid coupling like the one you linked to or a flexible shaft coupling. Quick note: I will be driving clutchless so I need the best coupling for a clutchless application.

Some drawbacks to the rigid coupling is the fact that I'll have to get it perfectly aligned with the motor and transmission shafts and I don't know if know if I have the tools for it. 57Chevy said this in my other thread about couplers:

if you make it rigid then your alignment needs to be absolutely perfect and you need to 'clock' the shafts to each other first by putting a DTI on one shaft and rotating it around the other in several places to ensure it is both parallel and concentric. This is not an easy task if your coupling lives hidden inside a bellhousing and even harder if you don't have a shimming/adjustment system. The jaw couplings allow easy assembly plus have a stated acceptable misalignment amount. Any misalignment in the shaft that is forced into alignment by tightening a rigid coupling will cause extra stresses and lead to something failing.

How did this process work for you? Was it easier?

My other option, the flexible shaft coupling, seems like it might work well. Here's the link to it: McMaster-Carr. What do you think of this option (specifically the one rated for 2075 in-lb of torque?

 

[cejota3]

Thank you for the feedback! I decided that a LoveJoy coupling wouldn't be reliable but now I'm stuck between getting a rigid coupling like the one you linked to or a flexible shaft coupling. Quick note: I will be driving clutchless so I need the best coupling for a clutchless application.

Some drawbacks to the rigid coupling is the fact that I'll have to get it perfectly aligned with the motor and transmission shafts and I don't know if know if I have the tools for it. 57Chevy said this in my other thread about couplers:

How did this process work for you? Was it easier?

My other option, the flexible shaft coupling, seems like it might work well. Here's the link to it: McMaster-Carr. What do you think of this option (specifically the one rated for 2075 in-lb of torque?

I've not seen that other flexible shaft coupler, but it does look a bit more stout than the LoveJoy. (And again, LoveJoy's are great, just not the best for this application IMHO.) That someone has used it successfully in an EV conversion is promising.
With all of that being said, I'd still lean pretty heavily towards a rigid coupling. Yes, it is definitely correct that the alignment needs to be very, very tight (and that is not only the X and Y axis, but also the Z). And I hear that you're going clutchless, but there are approaches to getting that alignment to where you need it. And finally, again, sorry I didn't read all the posts, just don't have the time right now, but for all of the reasons to go clutchless, in the end, overall, I fall in the camp of generally keeping a clutch. Yes, you loose some efficiency with the flywheel, but it really isn't as much as many make it out to be. And even though you end up using the clutch very little (compared to the ICE setup), it does make a few situations much easier when you have it; and the alignment issue becomes easier with a clutch setup (not "easy", but "easier").
Not trying to talk you out of your approach, as we've all got to pull these together our own ways; just letting you know my experiences.
Good luck!

 

[sifawangiaEV]

I've not seen that other flexible shaft coupler, but it does look a bit more stout than the LoveJoy. (And again, LoveJoy's are great, just not the best for this application IMHO.) That someone has used it successfully in an EV conversion is promising.
With all of that being said, I'd still lean pretty heavily towards a rigid coupling. Yes, it is definitely correct that the alignment needs to be very, very tight (and that is not only the X and Y axis, but also the Z). And I hear that you're going clutchless, but there are approaches to getting that alignment to where you need it. And finally, again, sorry I didn't read all the posts, just don't have the time right now, but for all of the reasons to go clutchless, in the end, overall, I fall in the camp of generally keeping a clutch. Yes, you loose some efficiency with the flywheel, but it really isn't as much as many make it out to be. And even though you end up using the clutch very little (compared to the ICE setup), it does make a few situations much easier when you have it; and the alignment issue becomes easier with a clutch setup (not "easy", but "easier").
Not trying to talk you out of your approach, as we've all got to pull these together our own ways; just letting you know my experiences.
Good luck!

I’m pretty set on going clutchless but I would like to try using a rigid coupling. How might I go about doing that right? Could I just send my motor and transmission and coupling to a machine shop and have them do it? What are your recommendations?