But the dynamics of an ICE automotive application are entirely different.We build racecars with that type of splined coupling all over the place and some of them are 30 years old and still going no problem. So is almost every clutch plate in existance. It's not an issue with the right design. And anti-fretting pastes.
In the early days of EV's Aviva Engineering and the IRTE did a study into why adding EV's to a vehicle fleet/pool was causing increased maintenance costs.Also that in an EV vehicle instant torque isn't really a thing, the delay for most people just actuating the accelerator alone from shut to open is probably half a second, and pedals certainly aren't mapped anywhere near linearly.
This is a fair point, although I would argue that given the different powertrain, the vehicle is inherently more vulnerable to those sorts of design inadequacies.The very fact that one side of the coupler is fine and one side is worn tells you it's not an inherent torque or shock loading issue, but a tolerance/sizing/tribology one.
A bit like people driving turbo diesels then?In the early days of EV's Aviva Engineering and the IRTE did a study into why adding EV's to a vehicle fleet/pool was causing increased maintenance costs.
The conclusion was basically "bad driving", with telemetry showing EV users routinely applying maximum acceleration and then breaking very harshly, especially in stop-start conditions, to an extent well beyond anything seen in any ICE user group.
Apparently statistically much worse, but the same principle of taking full advantage of having low down torque and letting the vehicle suffer for their sins.A bit like people driving turbo diesels then?
So is almost every clutch plate in existance.
Using the top grade Studlock during assembly helps take out any micro vibrations . On the Mk1 Mighty Antar we managed 20 thou clearance take out on six inch dia bearings without mishap.Fretting is usually the cause of such wear, small cyclic movements over time
"Curvic Coupling"Clutch plates on splines, CV joints, prop shafts, etc. aren't the same issue - in those the spline only has to deal with pure torque and sliding movement; there's no side loading on it. If the shafts are free to align themselves with each other (e.g. one of them is relatively long) then it isn't a significant issue. However, when you stick a splined sleeve over two short, stiff shafts, any misalignment puts a side load on it. If there is *any* clearance between the shafts and the sleeve (there will be), the sleeve will run at a slight angle between the shafts. With every revolution, each individual spline will move slightly backwards and forwards within the angled sleeve (a similar sort of movement to a rotary broach) causing fretting wear.
Sometimes shafts can have crowned splines (and are appropriately lubricated) to accommodate this sort of movement, but it doesn't *look* like they are in the OP's case.
I'm confused by this. My limited understanding was that there was a logic circuit in the control between the pedal and the motor. Why wasn't there a more gentle application of power built in? Afterall it's NOT a turbo diesel, which can only do what it does.Apparently statistically much worse, but the same principle of taking full advantage of having low down torque and letting the vehicle suffer for their sins.
Most all high powered motorcycles have several power modes that can be selected, so you’d think EVs would too.I'm confused by this. My limited understanding was that there was a logic circuit in the control between the pedal and the motor. Why wasn't there a more gentle application of power built in? Afterall it's NOT a turbo diesel, which can only do what it does.
Oldham coupling would work better, with slightly misaligned shafts."Curvic Coupling"
The Aviva/IRTE study was based on how people chose to operate the vehicle, not the inherent design decisions.I'm confused by this. My limited understanding was that there was a logic circuit in the control between the pedal and the motor. Why wasn't there a more gentle application of power built in? Afterall it's NOT a turbo diesel, which can only do what it does.
Yes, here is multiple solutions:Oldham coupling would work better, with slightly misaligned shafts.
The driveshaft on my old Yamaha XJ has a curved splined coupling at the bevel gear end - the only one I've seen."Curvic Coupling"
Clutch plates on splines, CV joints, prop shafts, etc. aren't the same issue - in those the spline only has to deal with pure torque and sliding movement; there's no side loading on it. If the shafts are free to align themselves with each other (e.g. one of them is relatively long) then it isn't a significant issue. However, when you stick a splined sleeve over two short, stiff shafts, any misalignment puts a side load on it. If there is *any* clearance between the shafts and the sleeve (there will be), the sleeve will run at a slight angle between the shafts. With every revolution, each individual spline will move slightly backwards and forwards within the angled sleeve (a similar sort of movement to a rotary broach) causing fretting wear.
Sometimes shafts can have crowned splines (and are appropriately lubricated) to accommodate this sort of movement, but it doesn't *look* like they are in the OP's case.
You can fix it in the software.There is normally some form of shock damping built into most drive trains, if there isnt a sprung hub in the clutch or flywheel there will be rubber dougnuts in the driveline.Designers of these leccy jobs seem to have missed a trick, I would have thought its getting equally hammered in both acceleration and in power recovery deaccelerating.
Bob
Stripped gearbox input splines is a bit of a problem on certain models of BMW bike. Everybody reckoned it’s because the bike isn’t stripped in half and the splines greased every couple of years.
But, research was done and apparently a certain quantity of gearboxes were manufactured incorrectly with the locating dowels offset by 0.5mm or so, which means the spline is continually being loaded eccentrically.
Maybe someone could look into this particular EV gearbox for some similar mass production cock up?