ALL POSTS - motor whine or "HUM" (Milling Sound)

[TonyWilliams]

http://www.youtube.com/watch?v=8LiI5xmDRbw

 

[doug401]

Ok just listened to it twice... Thanks for recording that. I'm sure I'll listen to it many more times in the future if/when the need arises. Good to have it documented.
Root Cause. That's the question. I learned from your video that the motor assembly and gear box assembly are all one assembly, making it more difficult to determine. Here are my guesses

Bearings... their tolerances or lube. Either the motor bearings or gear bearings.

Alignment... The motor shaft, or maybe reduction gears. This could support the heat vs noise variation.

Gear surfaces... Galling. Perhaps not machined to tolerance, or not hardened correctly. Lube... Lube is very specific nowadays.

Design... I hope not

But I am not worried. It's mechanical. Sure, it's an EV, but the E doesn't have anything to do with it. It has to do with the V part. No need for the Software Engineers, the Electrical Engineers can go home too. The Mechanical Engineers at Tesla are probably thriving on this type of trouble shooting. They live for it. I would love to see a illustrated parts breakdown of the motor gearbox assembly. It's probably proprietary. There are huge loads inside it. I have complete confidence in Tesla and Toyota.

 

[cwerdna]

http://www.youtube.com/watch?v=8LiI5xmDRbw

Wow! Interesting...

I was thinking it was possibly tire noise as well. But, if the motor replacement fixes it, we'll know it's not the tires.

 

[Dsinned]

No offense to anyone, but the noise (under hard acceleration) I heard in Tony's underhood You tube video recording actually sounds sorta like a high performance sports car at full throttle. IOW, it sounds kinda cool! :mrgreen: If my car made that noise, quite frankly, I might prefer to keep it that way instead of taking a risk on a major warranty repair which will likely be done by a Toyota automotive technician who never worked on a RAV4 EV before. On the other hand if it makes that noise at steady throttle, or while on CC, while I was listening to the stereo, I would probably be next in line for the same R&R at the dealer.

For those having this problem is it only happening under heavy throttle, or at higher drivetrain rpm, or all the time???

 

[occ]

http://www.youtube.com/watch?v=8LiI5xmDRbw

Thanks Tony, this is exactly the documentation we need for those of us who might be trying to convince Toyota to look at our own situation.

The hum is definitely what I'm hearing in my rav, but not that loud (or as loud in the cabin). I don't think that is tire noise, as reducing the power reduces the frequency and level immediately while vehicle speed does not slow down that quickly to change the hum like that...although tire/rd noise is prob a component of what is recorded. It's hard for most to tell whether this is normal since the mic is right next to the motor. I think the real test is for owners to see whether they hear this hum over road/wind noise from inside the cabin. I will also add that in my rav, the hum is louder at 55F than at 75F, so I think there's a temperature dependence here as well.

I've met up with yblaser, and driven in his rav (thanks yblaser!), and I can say that his motor hum was barely noticeable, where I had to be quite attentive to hear it (we had turned all cc/radio/etc off).

 

[occ]

No offense to anyone, but the noise (under hard acceleration) I heard in Tony's underhood You tube video recording actually sounds sorta like a high performance sports car at full throttle. IOW, it sounds kinda cool! :mrgreen: If my car made that noise, quite frankly, I might prefer to keep it that way instead of taking a risk on a major warranty repair which will likely be done by a Toyota automotive technician who never worked on a RAV4 EV before. On the other hand if it makes that noise at steady throttle, or while on CC, while I was listening to the stereo, I would probably be next in line for the same R&R at the dealer.

For those having this problem is it only happening under heavy throttle, or at higher drivetrain rpm, or all the time???

LOL That's what I thought too!...wow, it sounds like a well-tuned engine!

I would say mine always makes the hum under throttle, usually louder with more power applied. Most of the time I can make it go away by reducing to no power (like coasting). I would say if you're on CC, and power is applied to keep the constant speed and you would hear the hum constantly. Someone described it as a bunch of bees around you...annoying when it's loud.

 

[TonyWilliams]

It's not a pleasant sound at all, and just growls while sending a nice vibration through the whole car. The audio doesn't do it justice. It actually interferes with peaceful radio listening.

Anyway, ya, that's what I'm talking about.

 

[doug401]

a nice vibration through the whole car.

This is the first time I've read it being described as "felt", not just "heard"

My Sunday afternoon 2 beer analysis left out harmonics as a possible cause. But if you can feel it, scratch that one. Tony... When your dealer is done with the parts change, could you see what the labor hours are. I'm assuming it's dropped from underneath while on a lift. I would think this is a very simple swap out.

You also mentioned 9 to 1 reduction. That is more than I would have guessed. But that is where all that great torque comes from. Still... it's a vastly simpler transmission compared to an ICE. Maybe 3 or 4 gears, and all fixed in position.

 

[moderate]

Very interesting... Before I purchased the RAV4, I was a Model S reservation holder. We test-drove at the factory in Fremont last summer, and again around Thanks Giving. For the first drive, I was driver. For the second, I was in the back. On the second drive, I could hear the motor when my wife was pressing the accelerator. It sounded like a Rice Rocket was behind us, itching to pass. I asked my wife if she heard it up front, she didn't. I asked her if she'd noticed it when she was in the back on the first drive. She didn't remember it.

This was the sound the car was making.

That sound was part of the reason I gave up my reservation and got the RAV4 (part, mind you).

Interesting that they were giving a demo with a defective car. Wonder if they knew?

Anyway, glad I made the decision I did.... so far.

 

[Kohler Controller]

I believe mine is starting to "hum" (1400 miles on the odometer), just as OCC has described in his. This is not the traditional AC Induction motor whine, rather more like road noise from the tires, except that it goes away if you remove the load from the motor. If it was tire road noise, it would be there regardless. I'm wondering if this is a gear reduction issue (mechanical) instead of a motor one (electronic). I'll be trying to notice if it gets louder. That's tough because I drive it every day and subtle changes may not be immediately observed, like a gradual loss of hearing. The true test will be when my wife drives it (about every other week) and if she says something, then I know it's happening. She doesn't know about the "hum" so shouldn't be influenced by the suggestion.

Tony, did you put the audio file on youtube? What is the update with your motor/drivetrain replacement?

 

[occ]

Yep, here:

http://www.youtube.com/watch?v=8LiI5xmDRbw

Or if I didn't link that right, this thread has Tony's recorded humming link:

http://www.myrav4ev.com/forum/viewtopic.php?f=8&t=251

 

[qwk]

I believe mine is starting to "hum" (1400 miles on the odometer), just as OCC has described in his. This is not the traditional AC Induction motor whine, rather more like road noise from the tires, except that it goes away if you remove the load from the motor. If it was tire road noise, it would be there regardless. I'm wondering if this is a gear reduction issue (mechanical) instead of a motor one (electronic). I'll be trying to notice if it gets louder. That's tough because I drive it every day and subtle changes may not be immediately observed, like a gradual loss of hearing. The true test will be when my wife drives it (about every other week) and if she says something, then I know it's happening. She doesn't know about the "hum" so shouldn't be influenced by the suggestion.

Tony, did you put the audio file on youtube? What is the update with your motor/drivetrain replacement?

That sounds like an inverter noise. My Model S has this noise and it really doesn't bother me. I can see how this would be louder in a rav4, since the motor is in the front. It is not a constant noise that varies with speed(gear noise), but a slight whine that is most prominent at about 20kw of acceleration or regen(inverter). From reading on TMC, the inverter noise is very common.

 

[doug401]

Tony,
I read on the "New Member" thread that you are getting the swap out today? and the Tesla and Toyota reps will be present? Since we have our best man on the job, I don't need to ask you to pump them for information. Root cause, they know, but will they say? Is the new assembly "fixed", or is it another vib waiting to happen? Is a recall in the future? Looking forward to hearing something substantial on this, as it seems it's the only dark cloud over the Rav4 EV, besides the charge timing issues, which is more of a stalled warm front. Weather analogies?... it's very early this morning

 

[occ]

Good heads up doug401. Please Tony, do pick on them for any in depth of info about the hum, and mention others "may" be having the same issue. Toyota is receptive, but currently not admitting that my particular car has any problem. Still working it with them, but it will be slow and agonizing (I'm not much of a squeaky wheel). We still need to know what "normal" is, objectively if possible. From a few samples of rav4ev owners on this forum, this doesn't sound normal, but by a varying degree.

I give lots of test drives in my LEAF, but lately I don't want to put people off about EVs in general so I'm holding off giving test drives in my rav4ev.

 

[AvLegends]

I can hear a slight whine that changes in pitch with acceleration/deceleration. Not sure if it is the motor or the inverter. My car is still pretty new with under 1k on it and 3 weeks old but I am very attuned to the sounds that it is making for obvious reasons discussed here.

I had, and traded in a 2012 PiP that had a very noticeable high pitched inverter whine when in EV... not real loud but noticeable. The Rav does not sound like this at all. The Prius whine was almost like a very high pitched "whistle". The Rav4 EV whine is loud enough and noticeable even with the radio turned down low. I don't know if my Rav is making noises loud enough to take in to the dealer at this point but I am going in if/when it gets louder. We'll see!

 

[AvLegends]

Good heads up doug401.
I give lots of test drives in my LEAF, but lately I don't want to put people off about EVs in general so I'm holding off giving test drives in my rav4ev.

Yes... gave my father-in-law a test drive last weekend and the first thing his girlfriend (yes, at 82 he has a girlfriend! ) said was "what's that noise"? I blew it off as the electric motor... but she heard it right off the bat none the less...

 

[occ]

I can hear a slight whine that changes in pitch with acceleration/deceleration. Not sure if it is the motor or the inverter. My car is still pretty new with under 1k on it and 3 weeks old but I am very attuned to the sounds that it is making for obvious reasons discussed here.

I had, and traded in a 2012 PiP that had a very noticeable high pitched inverter whine when in EV... not real loud but noticeable. The Rav does not sound like this at all. The Prius whine was almost like a very high pitched "whistle". The Rav4 EV whine is loud enough and noticeable even with the radio turned down low. I don't know if my Rav is making noises loud enough to take in to the dealer at this point but I am going in if/when it gets louder. We'll see!

That slight whine during acceleration/deceleration to me is a normal EV characteristic motor upwhine/downwhine (although louder in the Rav than my LEAF). That sound very short duration, usually not more than 1-2 sec as you start your acceleration from stop, or just about to stop on your deceleration. The "hum" that "I THINK" is abnormal is a constant hum during constant power application to keep constant speeds of 65mph.

Try this experiment...get going at freeway speed (60mph+), and keep applying power. Note ambient sounds. Then let off on the accelerator until you stop applying power (basically coast at the same speed), and note any different in ambient sound. Mine makes a very noticeable "hum" difference.

Edit: need to qualify the "hum" difference. If you can hear the "difference" ABOVE road/wind noise, then I think it's not normal, as I have test driven in other rav4ev's where this difference is just not loud above road/wind noise. Even mine is louder than road/wind noise usually when weather is cold. In warmer weather, it *seems* just above road/wind to be barely noticeable.

 

[AvLegends]

Thanks! I will give that a try and report back...

 

[ToddR]

I noticed mine has an audible motor hum between 63-67 mhp. It seems strictly related to velocity, and unrelated to acceleration/deceleration. When I have a chance, I will have my wife drive and try to use a sound level meter and spectrum analyzer to get a breakdown of the noise, but I guess its some harmonic of the motor.

At least in my case the noise is not that bad, and easily lost in background road noise.

 

[TonyWilliams]

I should have my car back tomorrow.