[skubajon]

Well I think I'm about to throw in the towel on my pulley system and go with straight lovejoy type couplers.

I get tons of noise when the belts are tight enough for minimal backlash, and way to loose to quiet them up. Alignment is pretty tricky too.

I can't remember the type off the top of my head but they are a 15mm wide belt, 5mm pitch (90percent sure without looking) trapezoidal type designed for precise motion and power trans.

So I've been thinking about the lovejoy L075 or L095 hubs. The 19mm motor end has a 6mm keyway which I can find everywhere for a good price.. the ball screw end though I'm concerned with

Its a 15mm shaft end with no keyway etc. Looking at the lovejoy hubs I see they just have the 2 set screws. Other Chinese couplers have a clamping style.

So my question. With 750w ac servos, am I going to be OK with lovejoy set screws, or do I need to look into bushings etc.

My other question is my motors are rated for 3000 rpm and my balls crews probably won't handle much more than say 1500 to 1800 rpm. Currently I'm using a 2 to 1 belt system for this. Am I going to have any issues running motors at half rpm?

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[steryd]

U can for peace of mind use some anareobic glue.
If U will be using motors with low rpm momentus and power will also be lower than nominal. Espacially power.

[skubajon]

Ahh, so if I run my ac servos say half rpm, I'm going to lose some of my power rating? I don't know much about electrical motors

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[awerby]

If you use set-screws, provide flats on your shaft for them, or they'll dig themselves in and be very difficult to deal with. Or you can get 15mm clamp-style couplers: MJC41-15-A, 15mm Jaw Coupling Hub, Aluminum | Ruland which I like better than the set-screw type. Your motors shouldn't have any problem running at half their potential speed; most of what you'll be doing will be considerably slower than that.

[skubajon]

OK so I can either go with Ryland style spider jaw coupling or Disc type coupling for about 1.5 times the price. I'm OK with price difference but want probably what's best.

So spider jaw or disc type coupler?

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[wizard]

Well I think I'm about to throw in the towel on my pulley system and go with straight lovejoy type couplers.

Interesting as I would tend to prefer a belt drive over a Lovejoy type coupler.

I get tons of noise when the belts are tight enough for minimal backlash, and way to loose to quiet them up. Alignment is pretty tricky too.

This might be indicating other issues, belt drives are generally pretty quiet. It would be interesting to see a video to understand this noise a bit better. Generally I don't hear the belts themselves over background noise, in almost every case the ball nuts will make more noise than the belts.

I can't remember the type off the top of my head but they are a 15mm wide belt, 5mm pitch (90percent sure without looking) trapezoidal type designed for precise motion and power trans.

So I've been thinking about the lovejoy L075 or L095 hubs. The 19mm motor end has a 6mm keyway which I can find everywhere for a good price.. the ball screw end though I'm concerned with

Its a 15mm shaft end with no keyway etc. Looking at the lovejoy hubs I see they just have the 2 set screws. Other Chinese couplers have a clamping style.

The biggest issue with Lovejoy style couplings is using the right spider. The compressible ones are obviously a problem but harder spiders imply tighter alignment.

The more demanding your system the less likely you will be happy with set screw couplings. This especially if you do a lot of back and forth with the motor hammering the couplings back and forth. You can get fairly good results out of set screw based couplings if you have a keyway and relatively large set screws and a willingness to torque those screws down tight. As mentioned above a form of Loctite can do wonders. At least one of those setscrews needs to bear on the key and the other ideally on a flat.

The biggest problem I see is that real servo grade couplings are expensive, especially if you go for a taper locking coupling. I'd also consider Oldham style couplings or other similar couplings directed at the motion control field. Generally I think of Lovejoy couplings as something to connect a pump to a motor.

So my question. With 750w ac servos, am I going to be OK with lovejoy set screws, or do I need to look into bushings etc.

It depends. Most modern machines tend to put clamping couplings on the servo motors. Many of those servo motors don't even come with keyways, the expectation being a high end coupling that will lock to the shaft.

My other question is my motors are rated for 3000 rpm and my balls crews probably won't handle much more than say 1500 to 1800 rpm. Currently I'm using a 2 to 1 belt system for this. Am I going to have any issues running motors at half rpm?

Certainly! The question is will they be an issue for you. The first thing to realize is that you will loose half the servos capability running it at half speed. You also run the risk of accidents over roving the lead screws if the servo drive isn't set up right. You may get the machine to run but you need to understand that you won't be getting optimal use out of the servo. Generally when you have a servo motor that can run at much higher speed than the linear components it is driving you want to "gear" down to be able to harness the full capacity of the servo. Your other option would be to forget the belt drive and to add a gear box to the servo motor though an anti backlash gear box adds considerable expense over a belt drive.

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What no iPhone?

[skubajon]

Interesting as I would tend to prefer a belt drive over a Lovejoy type coupler.

This might be indicating other issues, belt drives are generally pretty quiet. It would be interesting to see a video to understand this noise a bit better. Generally I don't hear the belts themselves over background noise, in almost every case the ball nuts will make more noise than the belts.

The biggest issue with Lovejoy style couplings is using the right spider. The compressible ones are obviously a problem but harder spiders imply tighter alignment.

The more demanding your system the less likely you will be happy with set screw couplings. This especially if you do a lot of back and forth with the motor hammering the couplings back and forth. You can get fairly good results out of set screw based couplings if you have a keyway and relatively large set screws and a willingness to torque those screws down tight. As mentioned above a form of Loctite can do wonders. At least one of those setscrews needs to bear on the key and the other ideally on a flat.

The biggest problem I see is that real servo grade couplings are expensive, especially if you go for a taper locking coupling. I'd also consider Oldham style couplings or other similar couplings directed at the motion control field. Generally I think of Lovejoy couplings as something to connect a pump to a motor.

It depends. Most modern machines tend to put clamping couplings on the servo motors. Many of those servo motors don't even come with keyways, the expectation being a high end coupling that will lock to the shaft.

Certainly! The question is will they be an issue for you. The first thing to realize is that you will loose half the servos capability running it at half speed. You also run the risk of accidents over roving the lead screws if the servo drive isn't set up right. You may get the machine to run but you need to understand that you won't be getting optimal use out of the servo. Generally when you have a servo motor that can run at much higher speed than the linear components it is driving you want to "gear" down to be able to harness the full capacity of the servo. Your other option would be to forget the belt drive and to add a gear box to the servo motor though an anti backlash gear box adds considerable expense over a belt drive.


What no iPhone?

No iphone...I believe in technology advancement

Well the 2 types of couplers I was looking at were 1, the jaw type and 2 the disc type offered by misumi. Dual disc to be exact.

I definitely think I have power to spare as my Y axis is dual AC servos at 750w each and x is a single.

The belts tight with minimal play are very loud. Like nails on a chalkboard sounding loud. Loosen them up and they are quiet enough to not hear when spindle is running. Problem with that is when I do small small movements like .0001 I can watch the belt flex in either direction. I do have to run about .0016 backlash comp to correct. Now this is with belts extremely tight, like .25 play in center of belt or so. Also very loud lol



I'm using t5 belts. Would idlers help with backlash?

Interesting as I would tend to prefer a belt drive over a Lovejoy type coupler.

This might be indicating other issues, belt drives are generally pretty quiet. It would be interesting to see a video to understand this noise a bit better. Generally I don't hear the belts themselves over background noise, in almost every case the ball nuts will make more noise than the belts.

The biggest issue with Lovejoy style couplings is using the right spider. The compressible ones are obviously a problem but harder spiders imply tighter alignment.

The more demanding your system the less likely you will be happy with set screw couplings. This especially if you do a lot of back and forth with the motor hammering the couplings back and forth. You can get fairly good results out of set screw based couplings if you have a keyway and relatively large set screws and a willingness to torque those screws down tight. As mentioned above a form of Loctite can do wonders. At least one of those setscrews needs to bear on the key and the other ideally on a flat.

The biggest problem I see is that real servo grade couplings are expensive, especially if you go for a taper locking coupling. I'd also consider Oldham style couplings or other similar couplings directed at the motion control field. Generally I think of Lovejoy couplings as something to connect a pump to a motor.

It depends. Most modern machines tend to put clamping couplings on the servo motors. Many of those servo motors don't even come with keyways, the expectation being a high end coupling that will lock to the shaft.

Certainly! The question is will they be an issue for you. The first thing to realize is that you will loose half the servos capability running it at half speed. You also run the risk of accidents over roving the lead screws if the servo drive isn't set up right. You may get the machine to run but you need to understand that you won't be getting optimal use out of the servo. Generally when you have a servo motor that can run at much higher speed than the linear components it is driving you want to "gear" down to be able to harness the full capacity of the servo. Your other option would be to forget the belt drive and to add a gear box to the servo motor though an anti backlash gear box adds considerable expense over a belt drive.


What no iPhone?

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[skubajon]

Another idea while searching world wide Web lol

If I upgrade to an AT5 belt system, (is it a lot better than htd5 or t5 which is my current), I'm not finding any type of pulleys that are clamp type which I have. So taper lock is what is ideal for me.. all the taper locks I can find have keyway and my balls crew shafts don't have keys.

Is that going to be an issue not using a key? The keyless hubs are just too expensive lol. I'll try to make some worst case if not

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